Fault Current Limiters in Power Systems: A Comprehensive Review

: Power systems are becoming more and more complex in nature due to the integration of several power electronic devices. Protection of such systems and augmentation of reliability as well as stability highly depend on limiting the fault currents. Several fault current limiters (FCLs) have been applied in power systems as they provide rapid and efﬁcient fault current limitation. This paper presents a comprehensive literature review of the application of different types of FCLs in power systems. Applications of superconducting and non-superconducting FCLs are categorized as: (1) application in generation, transmission and distribution networks; (2) application in alternating current (AC)/direct current (DC) systems; (3) application in renewable energy resources integration; (4) application in distributed generation (DG); and (5) application for reliability, stability and fault ride through capability enhancement. Modeling, impact and control strategies of several FCLs in power systems are presented with practical implementation cases in different countries. Recommendations are provided to improve the performance of the FCLs in power systems with modiﬁcation of its structures, optimal placement and proper control design. This review paper will be a good foundation for researchers working in power system stability issues and for industry to implement the ongoing research advancement in real systems. paper provides a broad view of the applications of several superconducting and non-superconducting FCLs in different branches of power networks. Structure and control techniques for several FCLs are discussed. Several optimal parameter selection and optimal placement techniques for FCLs are provided. Practical implementation cases in different countries with field tests are discussed. Lastly, current challenges for FCL application are addressed and future works are recommended.


Introduction
Nowadays, the transmission lines of power systems are being stressed to transfer larger amounts of power, much closer to their thermal limit, than were considered when built. Power resources are limited and are increasingly more uncertain and variable. The integration of several renewable energy resources, including large-scale wind farms, into the existing grid is a great challenge for power system researchers. It increases the complexity of the electric networks with an inherently high short circuit rate. Generally, the electric networks are vulnerable to AC/DC faults and sophisticated protection apparatus and procedures need to be developed to avoid costly or even irremediable damage. Current limiting reactors are used in power systems for limiting short circuit currents and avoiding damage to the power system due to excessive fault currents. However, current limiting reactors have impedance during normal operation of the system [1].
The stability and security of electric power systems has become increasingly significant due to their complex nature. The application of a fault current limiter is one of the promising solutions to the stability and security issues of power systems. Different kinds of fault current limiters, such as resistive, inductive, superconducting, non-superconducting, flux-lock, DC reactor and resonance FCL, have been offered for limiting fault currents and improving the dynamic stability of power systems [2][3][4][5][6]. Resistive-type and inductive-type FCLs provide nearly zero impedance under normal operating conditions, whereas they provide high-impedance resistors or inductors in faulty conditions. Recently, a number of practical superconducting fault current limiter (SFCL) devices have been effectively developed and verified by in-grid tests. The present focus on applied superconductivity technology to build SFCL devices has been moving from the 10-kV distribution level [7,8] to the 100-kV transmission level [8,9].
This paper provides a broad view of the applications of several superconducting and non-superconducting FCLs in different branches of power networks. Structure and control techniques for several FCLs are discussed. Several optimal parameter selection and optimal placement techniques for FCLs are provided. Practical implementation cases in different countries with field tests are discussed. Lastly, current challenges for FCL application are addressed and future works are recommended.
The paper is organized as follows: Section 2 provides a general overview of the application of FCLs in several branches of power systems; the structure and working principles of superconducting and non-superconducting FCLs are discussed in Sections 3 and 4 respectively; optimal placement techniques for FCLs are provided in Section 5; the practical implementation issues for FCLs in different countries and field-testing results are discussed in Section 6; stability augmentation in different branches of power systems with FCLs are presented in Section 7; current challenges for FCLs application and some future works are recommended in Section 8; and finally, Section 9 highlights the major conclusions of this survey.

Superconducting FCL
Non-superconducting FCL Transmission Line [20][21][22] Distributed Generation [18,23,24] Distribution Network [28][29][30] Renewable Energy [25][26][27] Transmission Line [31] Distributed Generation [32,33] Distribution Network [35] Renewable Energy [10,12,34]  Both superconducting FCL and non-superconducting FCL have been extensively applied in transmission and distribution networks and renewable energy systems for different purposes such as stability enhancement, protection improvement, fault current reduction and fault ride through capability enhancement. Main advantages and disadvantages of superconducting and non-superconducting FCLs are summarized in Table 1. Both superconducting FCL and non-superconducting FCL have been extensively applied in transmission and distribution networks and renewable energy systems for different purposes such as stability enhancement, protection improvement, fault current reduction and fault ride through capability enhancement. Main advantages and disadvantages of superconducting and non-superconducting FCLs are summarized in Table 1.

Items Superconducting FCL Non-Superconducting FCL References
Size and weight Big size and heavy weight. Small in size and less weight. [36,37] Cost As the required inductor and resistor are superconducting nature, it has high implantation cost.
Less cost due to non-superconducting nature of required inductor and resistor.
It has loss in normal operation of the system. [42][43][44][45] Implementation status Some of them like saturated iron core, hybrid and resistive SFCL have been practically implemented in power systems in some countries. Table 1. Comparisons of superconducting and non-superconducting FCLs.

Items Superconducting FCL Non-Superconducting FCL References
Size and weight Big size and heavy weight. Small in size and less weight. [36,37] Cost As the required inductor and resistor are superconducting nature, it has high implantation cost.
Less cost due to non-superconducting nature of required inductor and resistor.

Superconducting FCLs
Depending on the structure and operating principle, superconducting fault current limiters (SFCLs) can be categorized as different types: Non-inductive reactor, inductive, transformer, resistive, hybrid, flux-lock and magnetic-shield.

Non-Inductive Type SFCL
A schematic diagram of non-inductive type SFCL is shown in Figure 2, which is made of two superconducting coils [60].   During the steady state mode of the power system, nearly zero impedance is shown by inductive SFCL as the zero impedance of the secondary superconducting winding is reflected to the primary. However, during system contingencies, resistance in the secondary is reflected in the primary circuits to limit the fault currents.

Transformer Type SFCL
Enhancement of supply reliability and power system stability have been observed with the transformer type SFCL [52,[62][63][64][65][66][67][68]. The primary side of the transformer type SFCL is connected in series with the load whereas the secondary side is connected in series with superconductors. The transformer type fault current limiter with vacuum interrupter is shown in the Figure 4. In Figure 4, L1 and L2 are the inductance in primary and secondary respectively. M is the mutual inductance between the primary and secondary coils of the transformer.  During the steady state mode of the power system, nearly zero impedance is shown by inductive SFCL as the zero impedance of the secondary superconducting winding is reflected to the primary. However, during system contingencies, resistance in the secondary is reflected in the primary circuits to limit the fault currents.

Transformer Type SFCL
Enhancement of supply reliability and power system stability have been observed with the transformer type SFCL [52,[62][63][64][65][66][67][68]. The primary side of the transformer type SFCL is connected in series with the load whereas the secondary side is connected in series with superconductors. The transformer type fault current limiter with vacuum interrupter is shown in the Figure 4. In Figure 4, L 1 and L 2 are the inductance in primary and secondary respectively. M is the mutual inductance between the primary and secondary coils of the transformer. A current limiting coil and a trigger coil are connected in anti-parallel and are magnetically coupled well. Different types of configurations like a coaxial coil arrangement and a bifilar winding arrangement were compared. The bifilar winding arrangement was found to be superior to have a high impedance ratio [60].

Inductive Type SFCL
Inductive type SFCL has two coaxial windings and an optional magnetic core [61]. Primary winding is made up of copper (Cu), whereas secondary winding is made up of a high temperature superconductor (HTS). The SFCL is cooled in a liquid nitrogen bath. The electrical connection diagram of inductive SFCL is shown in Figure 3. During the steady state mode of the power system, nearly zero impedance is shown by inductive SFCL as the zero impedance of the secondary superconducting winding is reflected to the primary. However, during system contingencies, resistance in the secondary is reflected in the primary circuits to limit the fault currents.

Transformer Type SFCL
Enhancement of supply reliability and power system stability have been observed with the transformer type SFCL [52,[62][63][64][65][66][67][68]. The primary side of the transformer type SFCL is connected in series with the load whereas the secondary side is connected in series with superconductors. The transformer type fault current limiter with vacuum interrupter is shown in the Figure 4. In Figure 4, L1 and L2 are the inductance in primary and secondary respectively. M is the mutual inductance between the primary and secondary coils of the transformer.  Upon the occurrence of faults, superconductors in the secondary side of the transformer are quenched, consequently, fault current in the secondary is limited to a lower value. Due to the current limiting in the secondary, fault current in the primary side is limited as well.

Resistive Type SFCL
Resistive type SFCL can improve the transient stability of the power system by suppressing the level of fault currents in a quick and efficient manner [5,[69][70][71][72][73][74][75][76][77][78][79]. A very simple structure of resistive SFCL is shown in Figure 5 consisting of nth units of stabilizing and superconducting resistances in parallel [5]. Coil inductance with nth units is connected in series with the parallel resistive branch.
Energies 2018, 11, x FOR PEER REVIEW 5 of 25 Upon the occurrence of faults, superconductors in the secondary side of the transformer are quenched, consequently, fault current in the secondary is limited to a lower value. Due to the current limiting in the secondary, fault current in the primary side is limited as well.

Resistive Type SFCL
Resistive type SFCL can improve the transient stability of the power system by suppressing the level of fault currents in a quick and efficient manner [5,[69][70][71][72][73][74][75][76][77][78][79]. A very simple structure of resistive SFCL is shown in Figure 5 consisting of nth units of stabilizing and superconducting resistances in parallel [5]. Coil inductance with nth units is connected in series with the parallel resistive branch. R nc (t) R ns (t) Figure 5. A simple structure of resistive SFCL.
In the normal steady state condition, the values of stabilizing (Rns) and superconducting (Rnc) resistances are zero. However, during fault conditions, these resistances become nonzero time-varying parameters to maintain superconducting states according to their unique characteristics. The value of the coil inductance is kept as small as possible in order to have minimal AC loss during normal operation. Therefore, the effect of the inductor during steady state operation is ignored.
A long length of the superconductor is needed to make a high voltage and high current system in case of resistive and inductive type SFCLs. However, this required length is significantly reduced in hybrid SFCL, which makes it commercially applicable [80].

Hybrid SFCL
Due to the slight critical current differences between the several units, resistive SFCL faces difficulty in quenching simultaneously between the units; however, this problem can be solved with hybrid SFCL [81]. Hybrid SFCL is proposed for limiting fault current and improving dynamic performance of power system [80][81][82][83]. A hybrid type SFCL has a primary winding and several secondary windings as shown in Figure 6 [81]. Each of the secondary windings is connected in series with a superconducting resistive unit. In Figure 6, LP is inductance in the primary winding of the transformer and LSA, LSB, LSC and ISA, ISB, ISB are the inductances and currents of secondary windings A, B and C respectively.  In the normal steady state condition, the values of stabilizing (R ns ) and superconducting (R nc ) resistances are zero. However, during fault conditions, these resistances become nonzero time-varying parameters to maintain superconducting states according to their unique characteristics. The value of the coil inductance is kept as small as possible in order to have minimal AC loss during normal operation. Therefore, the effect of the inductor during steady state operation is ignored.
A long length of the superconductor is needed to make a high voltage and high current system in case of resistive and inductive type SFCLs. However, this required length is significantly reduced in hybrid SFCL, which makes it commercially applicable [80].

Hybrid SFCL
Due to the slight critical current differences between the several units, resistive SFCL faces difficulty in quenching simultaneously between the units; however, this problem can be solved with hybrid SFCL [81]. Hybrid SFCL is proposed for limiting fault current and improving dynamic performance of power system [80][81][82][83]. A hybrid type SFCL has a primary winding and several secondary windings as shown in Figure 6 [81]. Each of the secondary windings is connected in series with a superconducting resistive unit. In Figure 6, L P is inductance in the primary winding of the transformer and L SA , L SB , L SC and I SA , I SB , I SB are the inductances and currents of secondary windings A, B and C respectively. Upon the occurrence of faults, superconductors in the secondary side of the transformer are quenched, consequently, fault current in the secondary is limited to a lower value. Due to the current limiting in the secondary, fault current in the primary side is limited as well.

Resistive Type SFCL
Resistive type SFCL can improve the transient stability of the power system by suppressing the level of fault currents in a quick and efficient manner [5,[69][70][71][72][73][74][75][76][77][78][79]. A very simple structure of resistive SFCL is shown in Figure 5 consisting of nth units of stabilizing and superconducting resistances in parallel [5]. Coil inductance with nth units is connected in series with the parallel resistive branch.
In the normal steady state condition, the values of stabilizing (Rns) and superconducting (Rnc) resistances are zero. However, during fault conditions, these resistances become nonzero time-varying parameters to maintain superconducting states according to their unique characteristics. The value of the coil inductance is kept as small as possible in order to have minimal AC loss during normal operation. Therefore, the effect of the inductor during steady state operation is ignored.
A long length of the superconductor is needed to make a high voltage and high current system in case of resistive and inductive type SFCLs. However, this required length is significantly reduced in hybrid SFCL, which makes it commercially applicable [80].

Hybrid SFCL
Due to the slight critical current differences between the several units, resistive SFCL faces difficulty in quenching simultaneously between the units; however, this problem can be solved with hybrid SFCL [81]. Hybrid SFCL is proposed for limiting fault current and improving dynamic performance of power system [80][81][82][83]. A hybrid type SFCL has a primary winding and several secondary windings as shown in Figure 6 [81]. Each of the secondary windings is connected in series with a superconducting resistive unit. In Figure 6, LP is inductance in the primary winding of the transformer and LSA, LSB, LSC and ISA, ISB, ISB are the inductances and currents of secondary windings A, B and C respectively.  During normal operation, resistance of the superconducting units connected in series with the secondary windings is zero. Therefore, current (I P ) flows through the power system without any loss. When fault appears on the system, superconducting unit is quenched and fault current is limited. In this way, hybrid SFCL has almost no effect on the system performance during normal operation and limits fault current during contingencies.

Flux-Lock Type SFCL
Among several of the SFCLs, the flux-lock type SFCL has less power burden of the high temperature superconducting (HTSC) element [53]. Short circuit current in power system can be limited with the flux-lock type fault current limiter during different contingencies [36,41,53,[84][85][86][87][88]. The configuration of the flux-lock type SFCL with over current relay is shown in the Figure 7 where N 1 , N 2 , N 3 and i 1 , i 2 , i 3 represent coil-1, coil-2 and coil-3 and their currents, respectively. ORC stands for over current relay. During normal operation, resistance of the superconducting units connected in series with the secondary windings is zero. Therefore, current (IP) flows through the power system without any loss. When fault appears on the system, superconducting unit is quenched and fault current is limited. In this way, hybrid SFCL has almost no effect on the system performance during normal operation and limits fault current during contingencies.

Flux-Lock Type SFCL
Among several of the SFCLs, the flux-lock type SFCL has less power burden of the high temperature superconducting (HTSC) element [53]. Short circuit current in power system can be limited with the flux-lock type fault current limiter during different contingencies [36,41,53,[84][85][86][87][88]. The configuration of the flux-lock type SFCL with over current relay is shown in the Figure 7 where N1, N2, N3 and i1, i2, i3 represent coil-1, coil-2 and coil-3 and their currents, respectively. ORC stands for over current relay.
Circuit Breaker Figure 7. Configuration of the flux-lock type SFCL.
As shown in Figure 7, the flux-lock type SFCL has two main parts-the current limiting part and the current interrupting part. The current limiting part consists of two parallel-connected coils and a high temperature superconductor (HTSC) connected in series with one of the coils. The current interrupting part consists of an over current relay driven by one of the parallel coils and a circuit breaker. During normal operation, zero voltage is induced across the coil as the magnetic fluxes generated in two coils are cancelled out. In faulty conditions, fault current is limited by the voltage generations across the coils.

Magnetic Shield Type SFCL
Magnetic shield type SFCLs have been reported in References [50,51,89,[90][91][92][93][94]. They consist of a primary copper coil and secondary high temperature superconductor (HTS) tube wound around a magnetic iron core [93] as shown in Figure 8. In the magnetic shield SFCL, screen currents thwart flux penetration into the iron core during standard operation as the HTS tube is fixed in between the primary copper winding and the magnetic core. As shown in Figure 7, the flux-lock type SFCL has two main parts-the current limiting part and the current interrupting part. The current limiting part consists of two parallel-connected coils and a high temperature superconductor (HTSC) connected in series with one of the coils. The current interrupting part consists of an over current relay driven by one of the parallel coils and a circuit breaker. During normal operation, zero voltage is induced across the coil as the magnetic fluxes generated in two coils are cancelled out. In faulty conditions, fault current is limited by the voltage generations across the coils.

Magnetic Shield Type SFCL
Magnetic shield type SFCLs have been reported in References [50,51,[89][90][91][92][93][94]. They consist of a primary copper coil and secondary high temperature superconductor (HTS) tube wound around a magnetic iron core [93] as shown in Figure 8. In the magnetic shield SFCL, screen currents thwart flux penetration into the iron core during standard operation as the HTS tube is fixed in between the primary copper winding and the magnetic core. During fault conditions, superconducting to a normal transition value is increased as the current exceeds critical value of HTS elements. Therefore, the resistance of the HTS tube is replicated in the primary circuit and magnetic flux infiltrates into the iron core augmenting impedance of the limiter. Table 2 summarizes superconducting FCLs in terms of cost, advantages, limitation and applications and so forth.  During fault conditions, superconducting to a normal transition value is increased as the current exceeds critical value of HTS elements. Therefore, the resistance of the HTS tube is replicated in the primary circuit and magnetic flux infiltrates into the iron core augmenting impedance of the limiter. Table 2 summarizes superconducting FCLs in terms of cost, advantages, limitation and applications and so forth. Table 2. Comparisons of different SFCLs in terms application, cost, pros and cons.

SFCL Types Advantages Disadvantages References
Non-inductive Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis.  Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis.  Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis. Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.

Less AC losses
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis.  Starbucks Company is the most widely prolific marketer and company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were: By applying our proposed model to Starbucks Company, selection of different strategies was anticipated to become simpler Step 1 Perform SWOT analysis.  Starbucks Company is the most widely prolific marketer and company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were:  Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis.
Weight and device size can be significantly reduced due to coreless construction Starbucks Company is the most widely prolific marketer and company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were: By applying our proposed model to Starbucks Company, selection of different strategies was anticipated to become simpler Step 1 Perform SWOT analysis.  Starbucks Company is the most widely prolific marketer and company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were: By applying our proposed model to Starbucks Company, selection of different strategies was anticipated to become simpler Step 1 Perform SWOT analysis.
Conventional circuit breaker is needed in order to switch off short circuit to avoid maximum HTS winding temperature.  Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis.
It can regulate fault current limiting range according to impedance ratio of transformer and hence applicable in the cases of wide range of current limiting process in detail.
The phases for implementing a N-AHP in SWOT analysis are shown in Figure 4. Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis.  Starbucks Company is the most widely prolific marketer and company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were: By applying our proposed model to Starbucks Company, selection of different strategies was anticipated to become simpler Step 1 Perform SWOT analysis.  Starbucks Company is the most widely prolific marketer and company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were: By applying our proposed model to Starbucks Company, selection of different strategies was anticipated to become simpler Step 1 Perform SWOT analysis.
Power burden of SFCL is higher [65] Resistive Symmetry 2018, 10, x FOR PEER REVIEW 8 o in order to measure its presumptive success. A company can appraise itself honestly and effectiv by performing SWOT analysis, which will help it examine its performance by analyzing internal a external factors. Once SWOT analysis is complete, a company will gain more information about capabilities. For the evaluation process, a multi-criteria decision-making technique should be use In this research, we used a neutrosophic AHP. A case study is offered in this section to illustrate t process in detail.
The phases for implementing a N-AHP in SWOT analysis are shown in Figure 4. Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis. in order to measure its presumptive success. A company can appraise itself honestly and effectiv by performing SWOT analysis, which will help it examine its performance by analyzing internal a external factors. Once SWOT analysis is complete, a company will gain more information about capabilities. For the evaluation process, a multi-criteria decision-making technique should be use In this research, we used a neutrosophic AHP. A case study is offered in this section to illustrate t process in detail.
The phases for implementing a N-AHP in SWOT analysis are shown in Figure 4. Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis.
Smaller in size, less costly and very simple structure by performing SWOT analysis, which will help it examine its perfo external factors. Once SWOT analysis is complete, a company wil capabilities. For the evaluation process, a multi-criteria decision-m In this research, we used a neutrosophic AHP. A case study is offe process in detail.
The phases for implementing a N-AHP in SWOT analysis are Starbucks Company is the most widely prolific marketer and company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were: By applying our proposed model to Starbucks Company, selection of different strategies was anticipated to become simpler Step 1 Perform SWOT analysis.
Long length of superconductor is required for high voltage application in order to measure its presumptive success. A company can appr by performing SWOT analysis, which will help it examine its perfo external factors. Once SWOT analysis is complete, a company wil capabilities. For the evaluation process, a multi-criteria decision-m In this research, we used a neutrosophic AHP. A case study is offe process in detail.
The phases for implementing a N-AHP in SWOT analysis are Starbucks Company is the most widely prolific marketer and company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were: By applying our proposed model to Starbucks Company, selection of different strategies was anticipated to become simpler Step 1 Perform SWOT analysis.
Large dissipated power and long recovery time Symmetry 2018, 10, x FOR PEER REVIEW in order to measure its presumptive success. A company can appr by performing SWOT analysis, which will help it examine its perfo external factors. Once SWOT analysis is complete, a company wil capabilities. For the evaluation process, a multi-criteria decision-m In this research, we used a neutrosophic AHP. A case study is offe process in detail.
The phases for implementing a N-AHP in SWOT analysis are Starbucks Company is the most widely prolific marketer and company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were: By applying our proposed model to Starbucks Company, selection of different strategies was anticipated to become simpler Step 1 Perform SWOT analysis.
Shortest recovery time could not be achieved even with neutral lines Symmetry 2018, 10, x FOR PEER REVIEW in order to measure its presumptive success. A company can appr by performing SWOT analysis, which will help it examine its perfo external factors. Once SWOT analysis is complete, a company wil capabilities. For the evaluation process, a multi-criteria decision-m In this research, we used a neutrosophic AHP. A case study is offe process in detail.
The phases for implementing a N-AHP in SWOT analysis are Starbucks Company is the most widely prolific marketer and company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were: By applying our proposed model to Starbucks Company, selection of different strategies was anticipated to become simpler Step 1 Perform SWOT analysis.
Simultaneous quenching is not possible due to critical current difference between several units [5,[69][70][71][72][73][74][75][76][77][78][79][80]97] Hybrid Symmetry 2018, 10, x FOR PEER REVIEW 8 o in order to measure its presumptive success. A company can appraise itself honestly and effectiv by performing SWOT analysis, which will help it examine its performance by analyzing internal a external factors. Once SWOT analysis is complete, a company will gain more information about capabilities. For the evaluation process, a multi-criteria decision-making technique should be use In this research, we used a neutrosophic AHP. A case study is offered in this section to illustrate t process in detail.
The phases for implementing a N-AHP in SWOT analysis are shown in Figure 4. Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis. in order to measure its presumptive success. A company can appraise itself honestly and effectiv by performing SWOT analysis, which will help it examine its performance by analyzing internal a external factors. Once SWOT analysis is complete, a company will gain more information about capabilities. For the evaluation process, a multi-criteria decision-making technique should be use In this research, we used a neutrosophic AHP. A case study is offered in this section to illustrate t process in detail.
The phases for implementing a N-AHP in SWOT analysis are shown in Figure 4. Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: in order to measure its presumptive success. A company can appr by performing SWOT analysis, which will help it examine its perfo external factors. Once SWOT analysis is complete, a company wil capabilities. For the evaluation process, a multi-criteria decision-m In this research, we used a neutrosophic AHP. A case study is offe process in detail.
The phases for implementing a N-AHP in SWOT analysis are Starbucks Company is the most widely prolific marketer and company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were:

SFCL Types Advantages Disadvantages References
Flux-lock different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators. These strategies were:  SO strategies  Amplifying global stores  Seeking higher growth markets  WO strategies  Adding different forms, new categories and diverse channels of products  Trying to minimize the coffee price  ST strategies  Taking precautions to mitigate economic crises and maintain profitability  WT strategies  Competing with other companies by offering different coffee and creating brand loyalty  Diversifying stores around the world and minimizing raw materials prices By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis.
Operational current could be varied company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis.
Less power burden on superconducting modules company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were: By applying our proposed model to Starbucks Company, selection of different strategies was anticipated to become simpler Step 1 Perform SWOT analysis.
Big size, heavy weight and high cost. [36,41,86,99] Magnetic Shield Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis.  Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis.
It has greater design flexibility due to turn ratio Starbucks Company is the most widely prolific marketer and retailer of coffee in the world. T company has branches in 75 countries, with more than 254,000 employees. The company also se different types of coffee and tea products and has a licensed trademark. The company offers food, addition to coffee, and this makes it an attractive spot for snacks and breakfast. The company h different competitors, such as Caribou Coffee Company, Costa Coffee, Green Mountain Cof Roasters and many others. To face competition, a group of experts perform Starbucks SWOT analys as shown in Figure 5. Depending on the SWOT factors and sub-factors, a set of alternatives strateg is developed. Our aim was to prioritize the strategies suggested by company indicators.
These strategies were: By applying our proposed model to Starbucks Company, the evaluation process and t selection of different strategies was anticipated to become simpler and more valuable.
Step 1 Perform SWOT analysis.
It provides isolation between SFCL and power network Starbucks Company is the most widely prolific marketer and company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were:  Starbucks Company is the most widely prolific marketer and company has branches in 75 countries, with more than 254,000 em different types of coffee and tea products and has a licensed tradem addition to coffee, and this makes it an attractive spot for snacks different competitors, such as Caribou Coffee Company, Costa Roasters and many others. To face competition, a group of experts p as shown in Figure 5. Depending on the SWOT factors and sub-fac is developed. Our aim was to prioritize the strategies suggested by These strategies were:  SO strategies By applying our proposed model to Starbucks Company, selection of different strategies was anticipated to become simpler Step 1 Perform SWOT analysis.
It has magnetic field interference which affects the operation of nearby sensitive devices [91,93,100,101]

Non-Superconducting FCLs
Generally, superconducting fault current limiters have been extensively used in power systems. However, non-superconducting fault current limiters could play an important role in reducing fault current and improving the dynamic stability of power systems with minimal cost compared to superconducting fault current limiters [10,34,97]. There are several types of non-superconducting fault current limiters as follows.

Series Dynamic Braking Resistor (SDBR)
SDBR is a non-superconducting FCL that has been extensively used in power systems, especially for the fault ride through capability enhancement of wind farms [54][55][56][57][58][59]. SDBR consists of a resistor in parallel with a switch. The switch is turned on and off based on the occurrence of a fault in the system. Due to fast response, IGBT is used as a switch as shown in Figure 9. During normal operation, IGBT is turned on and the braking resistor is bypassed. Therefore, the SDBR has no effect on the system during normal condition of the grid. At the inception of grid fault, voltage at the point of common coupling (Vpcc) decreases and becomes lower than the predefined reference voltage (Vref). IGBT is turned off at this condition and braking resistor comes in series with the line to limit the sharp increase in line current. Braking resistor continues to be in series with the line until Vpcc becomes greater than Vref. When Vpcc surpasses Vref, IGBT is turned on and system returns to its normal operation.

Bridge Type Fault Current Limiter (BFCL)
BFCL has two main parts-the bridge part and the shunt branch [102,103], as shown in Figure 10. During normal operation, IGBT is turned on and the braking resistor is bypassed. Therefore, the SDBR has no effect on the system during normal condition of the grid. At the inception of grid fault, voltage at the point of common coupling (V pcc ) decreases and becomes lower than the predefined reference voltage (V ref ). IGBT is turned off at this condition and braking resistor comes in series with the line to limit the sharp increase in line current. Braking resistor continues to be in series with the

Bridge Type Fault Current Limiter (BFCL)
BFCL has two main parts-the bridge part and the shunt branch [102,103], as shown in Figure 10. During normal operation, IGBT is turned on and the braking resistor is bypassed. Therefore, the SDBR has no effect on the system during normal condition of the grid. At the inception of grid fault, voltage at the point of common coupling (Vpcc) decreases and becomes lower than the predefined reference voltage (Vref). IGBT is turned off at this condition and braking resistor comes in series with the line to limit the sharp increase in line current. Braking resistor continues to be in series with the line until Vpcc becomes greater than Vref. When Vpcc surpasses Vref, IGBT is turned on and system returns to its normal operation.

Bridge Type Fault Current Limiter (BFCL)
BFCL has two main parts-the bridge part and the shunt branch [102,103], as shown in Figure 10. The main function of BFCL is to insert resistance and induction at the inception of a fault. It does not require superconductive characteristics for its operation, thus it has less application costs compared to other fault current limiting devices. The bridge part is composed of a diode rectifier, a very small dc limiting reactor (LDC), a small DC resistance (RDC), a commercially available semiconductor (IGBT) switch (CM200HG-130H) and a freewheeling diode. The main shunt branch is connected in parallel with the bridge part. It consists of a series of connected resistance and reactance (Rsh + jωLsh).
During normal operation, the IGBT switch is turned on and current flows through the path D1-LDC-RDC-D4 for positive half cycle of the signal. Then, current conducts through the path D2-LDC-RDC -D3 for negative half cycle of the signal. As the current through the LDC has unified direction during this normal operating condition LDC is charged to the peak of the line current and essentially behaves like short circuit and it has negligible voltage drop. Consequently, BFCL has no impact on the system in normal operating conditions. During contingencies, the IGBT switch is turned off and essentially the bridge behaves like an open circuit. So, the shunt path of the BFCL comes into operation and limits the fault current. At the same time, the freewheeling diode provides a discharge The main function of BFCL is to insert resistance and induction at the inception of a fault. It does not require superconductive characteristics for its operation, thus it has less application costs compared to other fault current limiting devices. The bridge part is composed of a diode rectifier, a very small dc limiting reactor (L DC ), a small DC resistance (R DC ), a commercially available semiconductor (IGBT) switch (CM200HG-130H) and a freewheeling diode. The main shunt branch is connected in parallel with the bridge part. It consists of a series of connected resistance and reactance (R sh + jωL sh ).
During normal operation, the IGBT switch is turned on and current flows through the path D 1 -L DC -R DC -D 4 for positive half cycle of the signal. Then, current conducts through the path D 2 -L DC -R DC -D 3 for negative half cycle of the signal. As the current through the L DC has unified direction during this normal operating condition L DC is charged to the peak of the line current and essentially behaves like short circuit and it has negligible voltage drop. Consequently, BFCL has no impact on the system in normal operating conditions. During contingencies, the IGBT switch is turned off and essentially the bridge behaves like an open circuit. So, the shunt path of the BFCL comes into operation and limits the fault current. At the same time, the freewheeling diode provides a discharge path for reactor (L DC ). It is worth mentioning that during fault initiation L DC the line current tends to increase drastically; however, L DC limits this current. Therefore, the IGBT switch is saved from high di/dt.

Modified Bridge Type Fault Current Limiter (MBFCL)
The structure of the bridge of the fault current limiter is rearranged to enhance low voltage ride through the capability of fixed speed and variable speed wind farms [49,104]. This new topology is named a modified bridge type fault current limiter (MBFCL). In BFCL shunt path consists of a series connected resistor and inductor. However, an inductor is omitted in MBFCL because it discharges when the shunt path is disconnected. During normal operation, MBFCL bridge is short-circuited as the IGBT gate signal is high, thus shunt branch resistance is bypassed. When a fault appears on the system, the IGBT gate signal becomes low by proper control action, the bridge part of the MBFCL is eventually open and shunt resistance is inserted in the line to limit the fault current.

DC Link Fault Current Limiter (DLFCL)
The DC link fault current limiter is proposed for fault ride through capability enhancement of an inverter based distributed generation system [32]. The non-superconducting DTFCL module is composed of a diode bridge and an inductive coil that has an inductor L d and very small resistance R d as shown in Figure 11. named a modified bridge type fault current limiter (MBFCL). In BFCL shunt path consists of a series connected resistor and inductor. However, an inductor is omitted in MBFCL because it discharges when the shunt path is disconnected. During normal operation, MBFCL bridge is short-circuited as the IGBT gate signal is high, thus shunt branch resistance is bypassed. When a fault appears on the system, the IGBT gate signal becomes low by proper control action, the bridge part of the MBFCL is eventually open and shunt resistance is inserted in the line to limit the fault current.

DC Link Fault Current Limiter (DLFCL)
The DC link fault current limiter is proposed for fault ride through capability enhancement of an inverter based distributed generation system [32]. The non-superconducting DTFCL module is composed of a diode bridge and an inductive coil that has an inductor Ld and very small resistance Rd as shown in Figure 11. During normal operation, the DC reactor has a negligible impact. However, the reactor can effectively suppress severe di/dt and it can limit fault current successfully over the fault duration.

Transformer Coupled BFCL
A transformer coupled bridge type fault current limiter is presented [105] for low voltage ride through (LVRT) capability enhancement of a doubly fed induction generator (DFIG). The schematic diagram of the fault current limiter is shown in Figure 12. A bypass resistor (Rb) is used to absorb the majority of the current harmonics during normal operation and to reduce voltage spikes. During normal operation, the DC reactor has a negligible impact. However, the reactor can effectively suppress severe di/dt and it can limit fault current successfully over the fault duration.

Transformer Coupled BFCL
A transformer coupled bridge type fault current limiter is presented [105] for low voltage ride through (LVRT) capability enhancement of a doubly fed induction generator (DFIG). The schematic diagram of the fault current limiter is shown in Figure 12. A bypass resistor (R b ) is used to absorb the majority of the current harmonics during normal operation and to reduce voltage spikes. In a steady state system, all the thyristors are kept turned on and limiting reactors are bypassed. During system disturbances, gate signals of the thyristors are removed and a limiting reactor is inserted to limit fault current. Table 3 summarizes different types of non-superconducting fault current limiters.  In a steady state system, all the thyristors are kept turned on and limiting reactors are bypassed. During system disturbances, gate signals of the thyristors are removed and a limiting reactor is inserted to limit fault current. Table 3 summarizes different types of non-superconducting fault current limiters.

Optimal Parameters and Placement of Fault Current Limiters
The optimal location for FCLs in a power network has several potential benefits. These include enhancing the system reliability and security, reducing fault current and voltage sag, improving fault ride through capability and increasing the interconnection of renewable energy. Several optimal placement techniques have been reported in the literature [14,18,23,[106][107][108][109][110][111][112][113]. Number of FCLs units, optimal parameters and optimal positions are considered for the placement of the FCLs in power system with several objectives like fault current reduction, reliability and stability improvement, FCL cost reduction and optimization of operating time of the over current relays. Some of the works focused on optimal placement mainly with single objective function as either fault current reduction [114,115] or stability enhancement [113]. Since there is the tradeoff among several objectives, enhancing one of them might lead to the deterioration of the others. Multiobjective optimization techniques [18,23,107,116] have been reported to solve the above mentioned problem. However, most of the optimal placement techniques do not take into account uncertainties in power systems, especially the unpredictable variations in the status of a DG, wind and PV systems when determining the best location for SFCL [14]. New placement algorithms can be developed considering several networks uncertainties for better performance. Table 4 summarizes optimal placement parameter selection techniques for different superconducting FCLs. in order to measure its presumptive success. A company ca by performing SWOT analysis, which will help it examine it external factors. Once SWOT analysis is complete, a compa capabilities. For the evaluation process, a multi-criteria dec In this research, we used a neutrosophic AHP. A case study process in detail.
The phases for implementing a N-AHP in SWOT analy Starbucks Company is the most widely prolific market company has branches in 75 countries, with more than 254 different types of coffee and tea products and has a licensed addition to coffee, and this makes it an attractive spot for different competitors, such as Caribou Coffee Company, Roasters and many others. To face competition, a group of ex as shown in Figure 5. Depending on the SWOT factors and s is developed. Our aim was to prioritize the strategies sugge These strategies were: By applying our proposed model to Starbucks Com selection of different strategies was anticipated to become s Step 1 Perform SWOT analysis.
Location and size can be obtained without any pre-assumptions.
Symmetry 2018, 10, x FOR PEER REVIEW in order to measure its presumptive success. A company ca by performing SWOT analysis, which will help it examine it external factors. Once SWOT analysis is complete, a compa capabilities. For the evaluation process, a multi-criteria dec In this research, we used a neutrosophic AHP. A case study process in detail.
The phases for implementing a N-AHP in SWOT analy Starbucks Company is the most widely prolific market company has branches in 75 countries, with more than 254 different types of coffee and tea products and has a licensed addition to coffee, and this makes it an attractive spot for different competitors, such as Caribou Coffee Company, Roasters and many others. To face competition, a group of ex as shown in Figure 5. Depending on the SWOT factors and s is developed. Our aim was to prioritize the strategies sugge These strategies were: in order to measure its presumptive success. A company ca by performing SWOT analysis, which will help it examine it external factors. Once SWOT analysis is complete, a compa capabilities. For the evaluation process, a multi-criteria dec In this research, we used a neutrosophic AHP. A case study process in detail.
The phases for implementing a N-AHP in SWOT analy Starbucks Company is the most widely prolific market company has branches in 75 countries, with more than 254 different types of coffee and tea products and has a licensed addition to coffee, and this makes it an attractive spot for different competitors, such as Caribou Coffee Company, Roasters and many others. To face competition, a group of ex as shown in Figure 5. Depending on the SWOT factors and s is developed. Our aim was to prioritize the strategies sugge These strategies were: in order to measure its presumptive success. A company ca by performing SWOT analysis, which will help it examine it external factors. Once SWOT analysis is complete, a compa capabilities. For the evaluation process, a multi-criteria dec In this research, we used a neutrosophic AHP. A case study process in detail.
The phases for implementing a N-AHP in SWOT analy Starbucks Company is the most widely prolific market company has branches in 75 countries, with more than 254 different types of coffee and tea products and has a licensed addition to coffee, and this makes it an attractive spot for different competitors, such as Caribou Coffee Company, Roasters and many others. To face competition, a group of ex as shown in Figure 5. Depending on the SWOT factors and s is developed. Our aim was to prioritize the strategies sugge These strategies were:  company has branches in 75 countries, with more than 254 different types of coffee and tea products and has a licensed addition to coffee, and this makes it an attractive spot for different competitors, such as Caribou Coffee Company, Roasters and many others. To face competition, a group of ex as shown in Figure 5. Depending on the SWOT factors and s is developed. Our aim was to prioritize the strategies sugge These strategies were:  Starbucks Company is the most widely prolific market company has branches in 75 countries, with more than 254 different types of coffee and tea products and has a licensed addition to coffee, and this makes it an attractive spot for different competitors, such as Caribou Coffee Company, Roasters and many others. To face competition, a group of ex as shown in Figure 5. Depending on the SWOT factors and s is developed. Our aim was to prioritize the strategies sugge These strategies were:

Diversifying stores around the world and minimi
By applying our proposed model to Starbucks Com selection of different strategies was anticipated to become s Step 1 Perform SWOT analysis.  Starbucks Company is the most widely prolific market company has branches in 75 countries, with more than 254 different types of coffee and tea products and has a licensed addition to coffee, and this makes it an attractive spot for different competitors, such as Caribou Coffee Company, Roasters and many others. To face competition, a group of ex as shown in Figure 5. Depending on the SWOT factors and s is developed. Our aim was to prioritize the strategies sugge These strategies were:

Diversifying stores around the world and minimi
By applying our proposed model to Starbucks Com selection of different strategies was anticipated to become s Step 1 Perform SWOT analysis.   Step 1 Perform SWOT analysis.
Method is straightforward and can be applied for any mesh network [107] Minimization of angular deviations between the rotors of the synchronous machines Transient stability index method Resistive SFCL IEEE benchmarked four-machine two-area test system  The phases for implementing a N-AHP in SWOT analy  The phases for implementing a N-AHP in SWOT analy  The phases for implementing a N-AHP in SWOT analy  The phases for implementing a N-AHP in SWOT analy  The phases for implementing a N-AHP in SWOT analy  Step 1 Perform SWOT analysis.
Sensitivity factor is introduced in the proposed method to reduce search space [110] Energies 2018, 11, 1025

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Some of the non-superconducting FCLs parameters design techniques have been presented in the literatures [104,117]. However, to the best of authors' knowledge, no optimization technique has been applied for either optimal parameter selection or optimal placement of non-superconducting FCLs.

Field Tests of FCLs
Although short circuit tests can be conducted to demonstrate current limiting capability of any developed SFCL, a field test is necessary to validate the performance and reliability. SFCL practical installing issues and field tests have been reported [17,[46][47][48][118][119][120][121][122][123]. In many countries FCLs have been practically installed and field tests have been done with results and recommendations for further study. Table 5 below shows field test results from different countries.  [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.

FCLs in Stability and Fault Ride Through Capability Enhancement
Due to the increased electrical power demand the fault levels in power systems increase causing severe damage to power system equipment. One of the main ways of enhancing power system stability and reliability is to interconnect the power systems for exchanging power among each other [124][125][126][127]. However, when fault occurs in the system, fault current is contributed to the fault point from all the interconnected parts which restrict interconnection to a certain extent so that the fault current could be kept within the breaking capability of the circuit breakers. Another feasible way is to employ fault current limiters in order to enhance reliability and stability of the interconnected power systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been reported [145,146] for limiting fault current as well as improving stability of active distribution network by reducing impact on circuit breaker. In [145], different types of SFCLs have been applied in a medium voltage active distribution network in order to investigate their impact on transient recovery voltage of circuit breaker. This investigation shows the capability of SFCLs in reducing both the magnitude and rate of rise of transient recovery voltage on circuit breaker which in turn improves system stability. Stability enhancement of microgrids, smart grids, multimachine systems, PV systems, high voltage direct current (HVDC) and wind systems has been observed with different fault current limiters such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard iron core FCL as shown in Figure 13. As clearly visualized in the Figure 13, [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.

FCLs in Stability and Fault Ride Through Capability Enhancement
Due to the increased electrical power demand the fault levels in power systems increase causing severe damage to power system equipment. One of the main ways of enhancing power system stability and reliability is to interconnect the power systems for exchanging power among each other [124][125][126][127]. However, when fault occurs in the system, fault current is contributed to the fault point from all the interconnected parts which restrict interconnection to a certain extent so that the fault current could be kept within the breaking capability of the circuit breakers. Another feasible way is to employ fault current limiters in order to enhance reliability and stability of the interconnected power systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been reported [145,146] for limiting fault current as well as improving stability of active distribution network by reducing impact on circuit breaker. In [145], different types of SFCLs have been applied in a medium voltage active distribution network in order to investigate their impact on transient recovery voltage of circuit breaker. This investigation shows the capability of SFCLs in reducing both the magnitude and rate of rise of transient recovery voltage on circuit breaker which in turn improves system stability. Stability enhancement of microgrids, smart grids, multimachine systems, PV systems, high voltage direct current (HVDC) and wind systems has been observed with different fault current limiters such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard iron core FCL as shown in Figure 13. As clearly visualized in the Figure 13, the superconducting Lightning partial discharge tests  [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.

FCLs in Stability and Fault Ride Through Capability Enhancement
Due to the increased electrical power demand the fault levels in power systems increase causing severe damage to power system equipment. One of the main ways of enhancing power system stability and reliability is to interconnect the power systems for exchanging power among each other [124][125][126][127]. However, when fault occurs in the system, fault current is contributed to the fault point from all the interconnected parts which restrict interconnection to a certain extent so that the fault current could be kept within the breaking capability of the circuit breakers. Another feasible way is to employ fault current limiters in order to enhance reliability and stability of the interconnected power systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been reported [145,146] for limiting fault current as well as improving stability of active distribution network by reducing impact on circuit breaker. In [145], different types of SFCLs have been applied in a medium voltage active distribution network in order to investigate their impact on transient recovery voltage of circuit breaker. This investigation shows the capability of SFCLs in reducing both the magnitude and rate of rise of transient recovery voltage on circuit breaker which in turn improves system stability. Stability enhancement of microgrids, smart grids, multimachine systems, PV systems, high voltage direct current (HVDC) and wind systems has been observed with different fault current limiters such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard iron core FCL as shown in Figure 13. As clearly visualized in the Figure 13, the superconducting  [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.

FCLs in Stability and Fault Ride Through Capability Enhancement
Due to the increased electrical power demand the fault levels in power systems increase causing severe damage to power system equipment. One of the main ways of enhancing power system stability and reliability is to interconnect the power systems for exchanging power among each other [124][125][126][127]. However, when fault occurs in the system, fault current is contributed to the fault point from all the interconnected parts which restrict interconnection to a certain extent so that the fault current could be kept within the breaking capability of the circuit breakers. Another feasible way is to employ fault current limiters in order to enhance reliability and stability of the interconnected power systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been reported [145,146] for limiting fault current as well as improving stability of active distribution network by reducing impact on circuit breaker. In [145], different types of SFCLs have been applied in a medium voltage active distribution network in order to investigate their impact on transient recovery voltage of circuit breaker. This investigation shows the capability of SFCLs in reducing both the magnitude and rate of rise of transient recovery voltage on circuit breaker which in turn improves system stability. Stability enhancement of microgrids, smart grids, multimachine systems, PV systems, high voltage direct current (HVDC) and wind systems has been observed with different fault current limiters such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard iron core FCL as shown in Figure 13. As clearly visualized in the Figure 13, the superconducting DC resistances and insulation resistances of the coils  [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.

FCLs in Stability and Fault Ride Through Capability Enhancement
Due to the increased electrical power demand the fault levels in power systems increase causing severe damage to power system equipment. One of the main ways of enhancing power system stability and reliability is to interconnect the power systems for exchanging power among each other [124][125][126][127]. However, when fault occurs in the system, fault current is contributed to the fault point from all the interconnected parts which restrict interconnection to a certain extent so that the fault current could be kept within the breaking capability of the circuit breakers. Another feasible way is to employ fault current limiters in order to enhance reliability and stability of the interconnected power systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been reported [145,146] for limiting fault current as well as improving stability of active distribution network by reducing impact on circuit breaker. In [145], different types of SFCLs have been applied in a medium voltage active distribution network in order to investigate their impact on transient recovery voltage of circuit breaker. This investigation shows the capability of SFCLs in reducing both the magnitude and rate of rise of transient recovery voltage on circuit breaker which in turn improves system stability. Stability enhancement of microgrids, smart grids, multimachine systems, PV systems, high voltage direct current (HVDC) and wind systems has been observed with different fault current limiters such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard iron core FCL as shown in Figure 13. As clearly visualized in the Figure 13, the superconducting  [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.

FCLs in Stability and Fault Ride Through Capability Enhancement
Due to the increased electrical power demand the fault levels in power systems increase causing severe damage to power system equipment. One of the main ways of enhancing power system stability and reliability is to interconnect the power systems for exchanging power among each other [124][125][126][127]. However, when fault occurs in the system, fault current is contributed to the fault point from all the interconnected parts which restrict interconnection to a certain extent so that the fault current could be kept within the breaking capability of the circuit breakers. Another feasible way is to employ fault current limiters in order to enhance reliability and stability of the interconnected power systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been reported [145,146] for limiting fault current as well as improving stability of active distribution network by reducing impact on circuit breaker. In [145], different types of SFCLs have been applied in a medium voltage active distribution network in order to investigate their impact on transient recovery voltage of circuit breaker. This investigation shows the capability of SFCLs in reducing both the magnitude and rate of rise of transient recovery voltage on circuit breaker which in turn improves system stability. Stability enhancement of microgrids, smart grids, multimachine systems, PV systems, high voltage direct current (HVDC) and wind systems has been observed with different  [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.

FCLs in Stability and Fault Ride Through Capability Enhancement
Due to the increased electrical power demand the fault levels in power systems increase causing severe damage to power system equipment. One of the main ways of enhancing power system stability and reliability is to interconnect the power systems for exchanging power among each other [124][125][126][127]. However, when fault occurs in the system, fault current is contributed to the fault point from all the interconnected parts which restrict interconnection to a certain extent so that the fault current could be kept within the breaking capability of the circuit breakers. Another feasible way is to employ fault current limiters in order to enhance reliability and stability of the interconnected power systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been reported [145,146] for limiting fault current as well as improving stability of active distribution network by reducing impact on circuit breaker. In [145], different types of SFCLs have been applied in a medium voltage active distribution network in order to investigate their impact on transient recovery voltage of circuit breaker. This investigation shows the capability of SFCLs in reducing both the magnitude and rate of rise of transient recovery voltage on circuit breaker which in turn improves system stability. Stability enhancement of microgrids, smart grids, multimachine systems,  [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.

FCLs in Stability and Fault Ride Through Capability Enhancement
Due to the increased electrical power demand the fault levels in power systems increase causing severe damage to power system equipment. One of the main ways of enhancing power system stability and reliability is to interconnect the power systems for exchanging power among each other [124][125][126][127]. However, when fault occurs in the system, fault current is contributed to the fault point from all the interconnected parts which restrict interconnection to a certain extent so that the fault current could be kept within the breaking capability of the circuit breakers. Another feasible way is to employ fault current limiters in order to enhance reliability and stability of the interconnected power systems [ [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.

FCLs in Stability and Fault Ride Through Capability Enhancement
Due to the increased electrical power demand the fault levels in power systems increase causing severe damage to power system equipment. One of the main ways of enhancing power system stability and reliability is to interconnect the power systems for exchanging power among each other [124][125][126][127]. However, when fault occurs in the system, fault current is contributed to the fault point from all the interconnected parts which restrict interconnection to a certain extent so that the fault current could be kept within the breaking capability of the circuit breakers. Another feasible way is to employ fault current limiters in order to enhance reliability and stability of the interconnected power systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been reported [145,146] for limiting fault current as well as improving stability of active distribution network by reducing impact on circuit breaker. In [145], different types of SFCLs have been applied  [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.

FCLs in Stability and Fault Ride Through Capability Enhancement
Due to the increased electrical power demand the fault levels in power systems increase causing severe damage to power system equipment. One of the main ways of enhancing power system stability and reliability is to interconnect the power systems for exchanging power among each other [124][125][126][127]. However, when fault occurs in the system, fault current is contributed to the fault point from all the interconnected parts which restrict interconnection to a certain extent so that the fault current could be kept within the breaking capability of the circuit breakers. Another feasible way is to employ fault current limiters in order to enhance reliability and stability of the interconnected power systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been reported [145,146] [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.

FCLs in Stability and Fault Ride Through Capability Enhancement
Due to the increased electrical power demand the fault levels in power systems increase causing severe damage to power system equipment. One of the main ways of enhancing power system stability and reliability is to interconnect the power systems for exchanging power among  [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.

FCLs in Stability and Fault Ride Through Capability Enhancement
Due to the increased electrical power demand the fault levels in power systems increase causing severe damage to power system equipment. One of the main ways of enhancing power  [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.  [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and Short circuit current test SFCL behavior for 24 h test duration in grid shows promising results [121,123] Long term operational tests have been performed in majority of the field tests to guarantee the reliability and performance of the SFCL devices. For example, the device temperature test to check whether it is within or above the tolerance value [47]. Determination of operational cost by measuring power consumption is one of the main requirements during long term operation tests of SFCL. However, only operational cost of hybrid SFCL [1,47] has been determined and compared with circuit breaker replacement cost and other damages to the power system equipment due to high fault currents. More discussion and feasibility analysis of other types of SFCLs are required with rigorous filed tests. Furthermore, non-superconducting solid state FCLs grid operation and field tests with feasibility analysis should be done in future work before real time grid integration.

FCLs in Stability and Fault Ride Through Capability Enhancement
Due to the increased electrical power demand the fault levels in power systems increase causing severe damage to power system equipment. One of the main ways of enhancing power system stability and reliability is to interconnect the power systems for exchanging power among each other [124][125][126][127]. However, when fault occurs in the system, fault current is contributed to the fault point from all the interconnected parts which restrict interconnection to a certain extent so that the fault current could be kept within the breaking capability of the circuit breakers. Another feasible way is to employ fault current limiters in order to enhance reliability and stability of the interconnected power systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been reported [145,146] for limiting fault current as well as improving stability of active distribution network by reducing impact on circuit breaker. In [145], different types of SFCLs have been applied in a medium voltage active distribution network in order to investigate their impact on transient recovery voltage of circuit breaker. This investigation shows the capability of SFCLs in reducing both the magnitude and rate of rise of transient recovery voltage on circuit breaker which in turn improves system stability. Stability enhancement of microgrids, smart grids, multimachine systems, PV systems, high voltage direct current (HVDC) and wind systems has been observed with different fault current limiters such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard iron core FCL as shown in Figure 13. As clearly visualized in the Figure 13, the superconducting FCLs have been examined with many branches of power system. However, non-superconducting FCL have been applied in few branches of power system. FCLs have been examined with many branches of power system. However, non-superconducting FCL have been applied in few branches of power system.  Different types of non-superconducting FCLs like bridge type fault current limiter (BFCL), parallel resonance bridge type fault current limiter (PRBFCL) have been examined in DFIG based wind integration, multimachine system and fixed speed wind system. Application of these non-superconducting FCL could be investigated in HVDC, smart grid, microgrid and multi-terminal HVDC (MTDC). Till date, some of the SFCLs have been practically implemented in some power systems in the world. However, non-superconducting fault current are yet to be implemented in real power system. Diodes and IGBT switches are mainly required for non-superconducting FCLs which can be implemented easily [104]. Moreover, required inductor and resistor for current limiting part  Different types of non-superconducting FCLs like bridge type fault current limiter (BFCL), parallel resonance bridge type fault current limiter (PRBFCL) have been examined in DFIG based wind integration, multimachine system and fixed speed wind system. Application of these non-superconducting FCL could be investigated in HVDC, smart grid, microgrid and multi-terminal HVDC (MTDC). Till date, some of the SFCLs have been practically implemented in some power systems in the world. However, non-superconducting fault current are yet to be implemented in real power system. Diodes and IGBT switches are mainly required for non-superconducting FCLs which can be implemented easily [104]. Moreover, required inductor and resistor for current limiting part are non-superconducting in nature which will reduce implementation cost excessively compared to superconducting fault current limiter for future in power system.

Industry Practices/Practical Implementation
Several experiments at industry levels or laboratory are performed prior to practical implementation of superconducting fault current limiters (SFCLs) in real system, especially for high voltage application of SFCL. To establish the winding technique of the largest high temperature superconductor (HTS) coil and build up the superconducting magnet system for high voltage application, for instance, 500 kV SFCL, short sample test of HTS wire and tension test of double pancake coil are performed in [147].
In [148], no-insulation (NI) coil is firstly applied in an inductive SFCL prototype as the secondary winding, which is magnetically coupled with the primary winding. A two-winding structure air-core prototype was developed with copper wire in primary winding and NI coils in secondary winding and this developed structure was brought under different experiments like short circuit test and impedance variation test which are needed before large-scale industrial production.
In South Korea, most of the power plants are located in the southern regions, while 40% of the loads are in northern regions. And, due to social and environmental constraints, installing additional power plant in southern region is difficult; as a result, more generators are added in the existing sites which cause more fault currents and instability in the systems. To resolve this issue, in [118], a novel hybrid type SFCL is presented. Although, in Korea, 22.9 kV hybrid SFCL was installed before, voltage level is still not as expected and recovery time is larger. This newly developed hybrid SFCL solves these problems.
In the framework of development of HTS based SFCL, Italian power system planners have done significant tests. After successful demonstration of techno-economic feasibility, 9 kV/3.4 MVA SFCL were installed. Second phase of Italian project for installation of 9 kV/15.6 MVA has been started [120] in the distribution grid of Milano region. This phase mainly focuses thermo-fluid dynamic behavior of cryogenic coolant flowing in forced convection through the superconducting cables.

Current Challenges and Future Works
Nowadays, high penetration of distributed generation in the form of PV, wind and energy storage interfaced with power electronic converters causes several technical issues especially high level of fault current. Moreover, power systems are becoming more complex with advances towards a smart grid consisting of control, computers, automation and new technology and equipment working together. It is a great challenge for power system researcher to secure stability of such system from high level of fault current. In order to reduce the stress on circuit breaker and other protective devices, fault current limiters are to be installed to keep fault current within permissible limit. However, their application, control, placement, field test, optimal parameter design are important and need further research. Although FCLs have been extensively studied and applied in AC system; their applications are quite limited in systems with HVDC. Multiterminal HVDC (MTDC) is evolving, where several converters are connected together to form a high voltage DC grid. Such system is more vulnerable to AC/DC faults. Coordination of superconducting and non-superconducting FCLs can be a better solution for MTDC. Still, a lot of challenges are there in developing and testing of non-superconducting FCLs in power system. From this comprehensive review, it is recommended that further research should be conducted to fill up the following gaps for FCLs application in power systems.  [121,123] ational tests have been performed in majority of the field tests to guarantee the rmance of the SFCL devices. For example, the device temperature test to check n or above the tolerance value [47]. Determination of operational cost by nsumption is one of the main requirements during long term operation tests of ly operational cost of hybrid SFCL [1,47] has been determined and compared replacement cost and other damages to the power system equipment due to More discussion and feasibility analysis of other types of SFCLs are required tests. Furthermore, non-superconducting solid state FCLs grid operation and bility analysis should be done in future work before real time grid integration.

and Fault Ride Through Capability Enhancement
reased electrical power demand the fault levels in power systems increase age to power system equipment. One of the main ways of enhancing power reliability is to interconnect the power systems for exchanging power among ]. However, when fault occurs in the system, fault current is contributed to the he interconnected parts which restrict interconnection to a certain extent so that ld be kept within the breaking capability of the circuit breakers. Another feasible fault current limiters in order to enhance reliability and stability of the er systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been or limiting fault current as well as improving stability of active distribution impact on circuit breaker. In [145], different types of SFCLs have been applied e active distribution network in order to investigate their impact on transient circuit breaker. This investigation shows the capability of SFCLs in reducing and rate of rise of transient recovery voltage on circuit breaker which in turn bility. Stability enhancement of microgrids, smart grids, multimachine systems, ltage direct current (HVDC) and wind systems has been observed with different s such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard own in Figure 13. As clearly visualized in the Figure 13, the superconducting  [121,123] ational tests have been performed in majority of the field tests to guarantee the rmance of the SFCL devices. For example, the device temperature test to check n or above the tolerance value [47]. Determination of operational cost by nsumption is one of the main requirements during long term operation tests of ly operational cost of hybrid SFCL [1,47] has been determined and compared replacement cost and other damages to the power system equipment due to More discussion and feasibility analysis of other types of SFCLs are required tests. Furthermore, non-superconducting solid state FCLs grid operation and bility analysis should be done in future work before real time grid integration.

and Fault Ride Through Capability Enhancement
reased electrical power demand the fault levels in power systems increase age to power system equipment. One of the main ways of enhancing power reliability is to interconnect the power systems for exchanging power among ]. However, when fault occurs in the system, fault current is contributed to the he interconnected parts which restrict interconnection to a certain extent so that ld be kept within the breaking capability of the circuit breakers. Another feasible fault current limiters in order to enhance reliability and stability of the er systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been or limiting fault current as well as improving stability of active distribution impact on circuit breaker. In [145], different types of SFCLs have been applied e active distribution network in order to investigate their impact on transient circuit breaker. This investigation shows the capability of SFCLs in reducing and rate of rise of transient recovery voltage on circuit breaker which in turn bility. Stability enhancement of microgrids, smart grids, multimachine systems, ltage direct current (HVDC) and wind systems has been observed with different s such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard own in Figure 13. As clearly visualized in the Figure 13, [121,123] ational tests have been performed in majority of the field tests to guarantee the rmance of the SFCL devices. For example, the device temperature test to check n or above the tolerance value [47]. Determination of operational cost by nsumption is one of the main requirements during long term operation tests of ly operational cost of hybrid SFCL [1,47] has been determined and compared replacement cost and other damages to the power system equipment due to More discussion and feasibility analysis of other types of SFCLs are required tests. Furthermore, non-superconducting solid state FCLs grid operation and bility analysis should be done in future work before real time grid integration. and Fault Ride Through Capability Enhancement reased electrical power demand the fault levels in power systems increase age to power system equipment. One of the main ways of enhancing power reliability is to interconnect the power systems for exchanging power among ]. However, when fault occurs in the system, fault current is contributed to the he interconnected parts which restrict interconnection to a certain extent so that ld be kept within the breaking capability of the circuit breakers. Another feasible fault current limiters in order to enhance reliability and stability of the er systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been or limiting fault current as well as improving stability of active distribution impact on circuit breaker. In [145], different types of SFCLs have been applied e active distribution network in order to investigate their impact on transient circuit breaker. This investigation shows the capability of SFCLs in reducing and rate of rise of transient recovery voltage on circuit breaker which in turn bility. Stability enhancement of microgrids, smart grids, multimachine systems, ltage direct current (HVDC) and wind systems has been observed with different s such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard own in Figure 13. As clearly visualized in the Figure 13, the superconducting Analysis, application and feasibility studies of non-superconducting FCLs in HVDC and MTDC systems in order to reduce vulnerability of system with AC/DC faults.  [121,123] ational tests have been performed in majority of the field tests to guarantee the rmance of the SFCL devices. For example, the device temperature test to check n or above the tolerance value [47]. Determination of operational cost by nsumption is one of the main requirements during long term operation tests of ly operational cost of hybrid SFCL [1,47] has been determined and compared replacement cost and other damages to the power system equipment due to More discussion and feasibility analysis of other types of SFCLs are required tests. Furthermore, non-superconducting solid state FCLs grid operation and bility analysis should be done in future work before real time grid integration. and Fault Ride Through Capability Enhancement reased electrical power demand the fault levels in power systems increase age to power system equipment. One of the main ways of enhancing power reliability is to interconnect the power systems for exchanging power among ]. However, when fault occurs in the system, fault current is contributed to the he interconnected parts which restrict interconnection to a certain extent so that ld be kept within the breaking capability of the circuit breakers. Another feasible fault current limiters in order to enhance reliability and stability of the er systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been or limiting fault current as well as improving stability of active distribution impact on circuit breaker. In [145], different types of SFCLs have been applied e active distribution network in order to investigate their impact on transient circuit breaker. This investigation shows the capability of SFCLs in reducing and rate of rise of transient recovery voltage on circuit breaker which in turn bility. Stability enhancement of microgrids, smart grids, multimachine systems, ltage direct current (HVDC) and wind systems has been observed with different s such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard own in Figure 13. As clearly visualized in the Figure 13, the superconducting Examining application FCLs for DFIG and or PMSG based large scale wind integrated VSC-HVDC system.  [121,123] ational tests have been performed in majority of the field tests to guarantee the rmance of the SFCL devices. For example, the device temperature test to check n or above the tolerance value [47]. Determination of operational cost by nsumption is one of the main requirements during long term operation tests of ly operational cost of hybrid SFCL [1,47] has been determined and compared replacement cost and other damages to the power system equipment due to More discussion and feasibility analysis of other types of SFCLs are required tests. Furthermore, non-superconducting solid state FCLs grid operation and bility analysis should be done in future work before real time grid integration. and Fault Ride Through Capability Enhancement reased electrical power demand the fault levels in power systems increase age to power system equipment. One of the main ways of enhancing power reliability is to interconnect the power systems for exchanging power among ]. However, when fault occurs in the system, fault current is contributed to the he interconnected parts which restrict interconnection to a certain extent so that ld be kept within the breaking capability of the circuit breakers. Another feasible fault current limiters in order to enhance reliability and stability of the er systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been or limiting fault current as well as improving stability of active distribution impact on circuit breaker. In [145], different types of SFCLs have been applied e active distribution network in order to investigate their impact on transient circuit breaker. This investigation shows the capability of SFCLs in reducing and rate of rise of transient recovery voltage on circuit breaker which in turn bility. Stability enhancement of microgrids, smart grids, multimachine systems, ltage direct current (HVDC) and wind systems has been observed with different s such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard own in Figure 13. As clearly visualized in the Figure 13, the superconducting Comparative studies of superconducting and non-superconducting FCLs in terms of economic aspects and performance analysis.  [121,123] ational tests have been performed in majority of the field tests to guarantee the rmance of the SFCL devices. For example, the device temperature test to check n or above the tolerance value [47]. Determination of operational cost by nsumption is one of the main requirements during long term operation tests of ly operational cost of hybrid SFCL [1,47] has been determined and compared replacement cost and other damages to the power system equipment due to More discussion and feasibility analysis of other types of SFCLs are required tests. Furthermore, non-superconducting solid state FCLs grid operation and bility analysis should be done in future work before real time grid integration. and Fault Ride Through Capability Enhancement reased electrical power demand the fault levels in power systems increase age to power system equipment. One of the main ways of enhancing power reliability is to interconnect the power systems for exchanging power among ]. However, when fault occurs in the system, fault current is contributed to the he interconnected parts which restrict interconnection to a certain extent so that ld be kept within the breaking capability of the circuit breakers. Another feasible fault current limiters in order to enhance reliability and stability of the er systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been or limiting fault current as well as improving stability of active distribution impact on circuit breaker. In [145], different types of SFCLs have been applied e active distribution network in order to investigate their impact on transient circuit breaker. This investigation shows the capability of SFCLs in reducing and rate of rise of transient recovery voltage on circuit breaker which in turn bility. Stability enhancement of microgrids, smart grids, multimachine systems, ltage direct current (HVDC) and wind systems has been observed with different s such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard own in Figure 13. As clearly visualized in the Figure 13, the superconducting Development of non-superconducting FCLs and conducting their field tests for real grid integration.  [121,123] ational tests have been performed in majority of the field tests to guarantee the rmance of the SFCL devices. For example, the device temperature test to check n or above the tolerance value [47]. Determination of operational cost by nsumption is one of the main requirements during long term operation tests of ly operational cost of hybrid SFCL [1,47] has been determined and compared replacement cost and other damages to the power system equipment due to More discussion and feasibility analysis of other types of SFCLs are required tests. Furthermore, non-superconducting solid state FCLs grid operation and bility analysis should be done in future work before real time grid integration. and Fault Ride Through Capability Enhancement reased electrical power demand the fault levels in power systems increase age to power system equipment. One of the main ways of enhancing power reliability is to interconnect the power systems for exchanging power among ]. However, when fault occurs in the system, fault current is contributed to the he interconnected parts which restrict interconnection to a certain extent so that ld be kept within the breaking capability of the circuit breakers. Another feasible fault current limiters in order to enhance reliability and stability of the er systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been or limiting fault current as well as improving stability of active distribution impact on circuit breaker. In [145], different types of SFCLs have been applied e active distribution network in order to investigate their impact on transient circuit breaker. This investigation shows the capability of SFCLs in reducing and rate of rise of transient recovery voltage on circuit breaker which in turn bility. Stability enhancement of microgrids, smart grids, multimachine systems, ltage direct current (HVDC) and wind systems has been observed with different s such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard own in Figure 13. As clearly visualized in the Figure 13, the superconducting Coordinated control strategy can be developed between flexible AC transmission system (FACTS) devices and FCLs.  [121,123] ational tests have been performed in majority of the field tests to guarantee the rmance of the SFCL devices. For example, the device temperature test to check n or above the tolerance value [47]. Determination of operational cost by nsumption is one of the main requirements during long term operation tests of ly operational cost of hybrid SFCL [1,47] has been determined and compared replacement cost and other damages to the power system equipment due to More discussion and feasibility analysis of other types of SFCLs are required tests. Furthermore, non-superconducting solid state FCLs grid operation and bility analysis should be done in future work before real time grid integration. and Fault Ride Through Capability Enhancement reased electrical power demand the fault levels in power systems increase age to power system equipment. One of the main ways of enhancing power reliability is to interconnect the power systems for exchanging power among ]. However, when fault occurs in the system, fault current is contributed to the he interconnected parts which restrict interconnection to a certain extent so that ld be kept within the breaking capability of the circuit breakers. Another feasible fault current limiters in order to enhance reliability and stability of the er systems [19,33,34,54,104,[128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144]. Implementation of SFCLs has been or limiting fault current as well as improving stability of active distribution impact on circuit breaker. In [145], different types of SFCLs have been applied e active distribution network in order to investigate their impact on transient circuit breaker. This investigation shows the capability of SFCLs in reducing and rate of rise of transient recovery voltage on circuit breaker which in turn bility. Stability enhancement of microgrids, smart grids, multimachine systems, ltage direct current (HVDC) and wind systems has been observed with different s such as SFCL, BFCL, DC link FCL, super capacitor switch FCL and standard own in Figure 13. As clearly visualized in the Figure 13, the superconducting Linearized model can be developed for the system comprising FCLs to conduct small signal stability analysis and design FCLs parameters.

Conclusions
The aim of this research is to offer a detailed and in-depth review of fault current limiters in power system. Application of FCLs in different branches of power systems like generation, transmission and distribution networks, AC/DC systems, renewable energy resources integration, distributed generation is reviewed and documented. The key discussion is divided into several parts, such as application of FCLs in several branches of power systems, categorizing and discussing the structure of several FCLs, pros and cons of different FCLs, real grid operation and testing of FCLs, optimal placement and parameter design and stability and fault ride through capability augmentation employing different FCLs. It is realized from the literature review that the FCLs placement is important in limiting fault current and augmenting stability of power system. However, a lot of challenges still are there in applying FCLs in power system such as minimizing interference with neighboring communication line, minimizing loss in normal operation, designing optimal parameters, coordinated control design between FCL and other protective devices, feasibility analysis, field test and real grid operation. Several gaps are presented in this review as challenges to FCL application and control in power systems, which are interesting topics for power system researchers.
Author Contributions: All authors contributed to this work by collaboration. Md Shafiul Alam is the first author in this manuscript. All authors revised and approved for the publication.