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Special Issue "Electric Power Systems Research 2017"

A special issue of Energies (ISSN 1996-1073).

Deadline for manuscript submissions: closed (28 February 2017).

Special Issue Editor

Guest Editor
Prof. Dr. Ying-Yi Hong

Department of Electrical Engineering, Chung Yuan Christian University, Taoyuan City, Taiwan
Website | E-Mail
Interests: smart grid; control and planning for microgrid; intelligent methods applied to power systems

Special Issue Information

Dear Colleagues,

People request that power grid utilities deliver electric power in a stable, reliable, secure, and sustainable manner, from the generation system through transmission and distribution systems to end-users. Consequently, the development of advanced technologies and novel methods applied to the modern power system is crucial. Especially, distributed generation resources, energy storage system, advanced control, demand response program, power market, and power quality are addressed in a modern power system.

“Electric Power Systems Research” is a Special Issue in Energies for those who would like to publish original papers about the generation, transmission, distribution and utilization of electrical energy. This Special Issue aims at presenting important results of work in power systems. The works can be applied research, development of new procedures or components, original application of existing knowledge or new design approaches.

Papers in the relevant area of “Electric Power Systems Research”, including but not limited to, the following are invited:

  1. power system stability
  2. power system reliability
  3. facts applied to power systems
  4. power system optimization
  5. intelligent methods applied to power system studies
  6. power market and demand response program
  7. control, operation and planning of distributed generation resources
  8. smart community with energy management systems
  9. microgrid and virtual power plant
  10. active distribution network
  11. harmonics/voltage power quality

Ying-Yi Hong, Ph.D., IET Fellow
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • stability
  • reliability
  • sustainability
  • security

Related Special Issue

Published Papers (30 papers)

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Research

Open AccessArticle
A Hybrid Reliability Evaluation Method for Meshed VSC-HVDC Grids
Energies 2017, 10(7), 895; https://doi.org/10.3390/en10070895
Received: 28 February 2017 / Revised: 7 June 2017 / Accepted: 28 June 2017 / Published: 1 July 2017
Cited by 4 | PDF Full-text (5638 KB) | HTML Full-text | XML Full-text
Abstract
High-voltage direct current (HVDC) grids are emerging, and their reliability has been an increasing concern for the utilities. HVDC grids are different from typical two-terminal HVDC transmission systems due to the loops in their topology, which makes it difficult to evaluate the reliability [...] Read more.
High-voltage direct current (HVDC) grids are emerging, and their reliability has been an increasing concern for the utilities. HVDC grids are different from typical two-terminal HVDC transmission systems due to the loops in their topology, which makes it difficult to evaluate the reliability by conventional analytical methods. This paper proposes an innovative hybrid method to evaluate the reliability of meshed HVDC grids. First, steady-state models and reliability models are established for the components in HVDC grids, especially for converters and power flow controllers. In the models, virtual buses are introduced to represent the external AC connections to the HVDC grid. Then a hybrid reliability evaluation method is proposed based on an analytical approach and Monte Carlo simulation. One innovation of the paper is the application of an analytical analysis method to accelerate state evaluation in Monte Carlo simulation by skipping unnecessary optimization. The proposed models and methods are verified on two HVDC grids. Test results show that HVDC grids under most failure states (approximately 70%) tend to shed no load except on buses connected to faulted converters, and the application of the analytical method could promote evaluation efficiency significantly. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
An Improved Droop Control Method for Multi-Terminal VSC-HVDC Converter Stations
Energies 2017, 10(7), 843; https://doi.org/10.3390/en10070843
Received: 1 March 2017 / Revised: 11 June 2017 / Accepted: 19 June 2017 / Published: 23 June 2017
Cited by 4 | PDF Full-text (2173 KB) | HTML Full-text | XML Full-text
Abstract
Multi-terminal high voltage direct current transmission based on voltage source converter (VSC-HVDC) grids can connect non-synchronous alternating current (AC) grids to a hybrid alternating current and direct current (AC/DC) power system, which is one of the key technologies in the construction of smart [...] Read more.
Multi-terminal high voltage direct current transmission based on voltage source converter (VSC-HVDC) grids can connect non-synchronous alternating current (AC) grids to a hybrid alternating current and direct current (AC/DC) power system, which is one of the key technologies in the construction of smart grids. However, it is still a problem to control the converter to achieve the function of each AC system sharing the reserve capacity of the entire network. This paper proposes an improved control strategy based on the slope control of the DC voltage and AC frequency (V–f slope control), in which the virtual inertia is introduced. This method can ensure that each AC sub-system shares the primary frequency control function. Additionally, with the new control method, it is easy to apply the secondary frequency control method of traditional AC systems to AC/DC hybrid systems to achieve the steady control of the DC voltage and AC frequency of the whole system. Most importantly, the new control method is better than the traditional control method in terms of dynamic performance. In this paper, a new control method is proposed, and the simulation model has been established in Matlab/Simulink to verify the effectiveness of the proposed control method. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Optimal Placement and Sizing of Renewable Distributed Generations and Capacitor Banks into Radial Distribution Systems
Energies 2017, 10(6), 811; https://doi.org/10.3390/en10060811
Received: 31 January 2017 / Revised: 9 June 2017 / Accepted: 11 June 2017 / Published: 14 June 2017
Cited by 9 | PDF Full-text (2569 KB) | HTML Full-text | XML Full-text
Abstract
In recent years, renewable types of distributed generation in the distribution system have been much appreciated due to their enormous technical and environmental advantages. This paper proposes a methodology for optimal placement and sizing of renewable distributed generation(s) (i.e., wind, solar and biomass) [...] Read more.
In recent years, renewable types of distributed generation in the distribution system have been much appreciated due to their enormous technical and environmental advantages. This paper proposes a methodology for optimal placement and sizing of renewable distributed generation(s) (i.e., wind, solar and biomass) and capacitor banks into a radial distribution system. The intermittency of wind speed and solar irradiance are handled with multi-state modeling using suitable probability distribution functions. The three objective functions, i.e., power loss reduction, voltage stability improvement, and voltage deviation minimization are optimized using advanced Pareto-front non-dominated sorting multi-objective particle swarm optimization method. First a set of non-dominated Pareto-front data are called from the algorithm. Later, a fuzzy decision technique is applied to extract the trade-off solution set. The effectiveness of the proposed methodology is tested on the standard IEEE 33 test system. The overall results reveal that combination of renewable distributed generations and capacitor banks are dominant in power loss reduction, voltage stability and voltage profile improvement. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Design of Nonlinear Robust Damping Controller for Power Oscillations Suppressing Based on Backstepping-Fractional Order Sliding Mode
Energies 2017, 10(5), 676; https://doi.org/10.3390/en10050676
Received: 25 February 2017 / Revised: 1 May 2017 / Accepted: 8 May 2017 / Published: 15 May 2017
Cited by 4 | PDF Full-text (1929 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, a novel nonlinear robust damping controller is proposed to suppress power oscillation in interconnected power systems. The proposed power oscillation damping controller exhibits good nonlinearity and robustness. It can consider the strong nonlinearity of power oscillation and uncertainty of its [...] Read more.
In this paper, a novel nonlinear robust damping controller is proposed to suppress power oscillation in interconnected power systems. The proposed power oscillation damping controller exhibits good nonlinearity and robustness. It can consider the strong nonlinearity of power oscillation and uncertainty of its model. First, through differential homeomorphic mapping, a mathematical model of the system can be transformed into the Brunovsky standard. Next, an extended state observer (ESO) estimated and compensated for model errors and external disturbances as well as uncertain factors to achieve dynamic linearization of the nonlinear model. A power oscillation damping controller for interconnected power systems was designed on a backstepping-fractional order sliding mode variable structure control theory (BFSMC). Compared with traditional methods, the controller exhibits good dynamic performance and strong robustness. Simulations involving a four-generator two-area and partial test system of Northeast China were conducted under various disturbances to prove the effectiveness and robustness of the proposed damping control method. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
A Network Reconfiguration Method Considering Data Uncertainties in Smart Distribution Networks
Energies 2017, 10(5), 618; https://doi.org/10.3390/en10050618
Received: 29 January 2017 / Revised: 25 April 2017 / Accepted: 26 April 2017 / Published: 2 May 2017
Cited by 5 | PDF Full-text (1620 KB) | HTML Full-text | XML Full-text
Abstract
This work presents a method for distribution network reconfiguration with the simultaneous consideration of distributed generation (DG) allocation. The uncertainties of load fluctuation before the network reconfiguration are also considered. Three optimal objectives, including minimal line loss cost, minimum Expected Energy Not Supplied, [...] Read more.
This work presents a method for distribution network reconfiguration with the simultaneous consideration of distributed generation (DG) allocation. The uncertainties of load fluctuation before the network reconfiguration are also considered. Three optimal objectives, including minimal line loss cost, minimum Expected Energy Not Supplied, and minimum switch operation cost, are investigated. The multi-objective optimization problem is further transformed into a single-objective optimization problem by utilizing weighting factors. The proposed network reconfiguration method includes two periods. The first period is to create a feasible topology network by using binary particle swarm optimization (BPSO). Then the DG allocation problem is solved by utilizing sensitivity analysis and a Harmony Search algorithm (HSA). In the meanwhile, interval analysis is applied to deal with the uncertainties of load and devices parameters. Test cases are studied using the standard IEEE 33-bus and PG&E 69-bus systems. Different scenarios and comparisons are analyzed in the experiments. The results show the applicability of the proposed method. The performance analysis of the proposed method is also investigated. The computational results indicate that the proposed network reconfiguration algorithm is feasible. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Statistical Feature Extraction for Fault Locations in Nonintrusive Fault Detection of Low Voltage Distribution Systems
Energies 2017, 10(5), 611; https://doi.org/10.3390/en10050611
Received: 25 February 2017 / Revised: 21 April 2017 / Accepted: 25 April 2017 / Published: 29 April 2017
Cited by 3 | PDF Full-text (2052 KB) | HTML Full-text | XML Full-text
Abstract
This paper proposes statistical feature extraction methods combined with artificial intelligence (AI) approaches for fault locations in non-intrusive single-line-to-ground fault (SLGF) detection of low voltage distribution systems. The input features of the AI algorithms are extracted using statistical moment transformation for reducing the [...] Read more.
This paper proposes statistical feature extraction methods combined with artificial intelligence (AI) approaches for fault locations in non-intrusive single-line-to-ground fault (SLGF) detection of low voltage distribution systems. The input features of the AI algorithms are extracted using statistical moment transformation for reducing the dimensions of the power signature inputs measured by using non-intrusive fault monitoring (NIFM) techniques. The data required to develop the network are generated by simulating SLGF using the Electromagnetic Transient Program (EMTP) in a test system. To enhance the identification accuracy, these features after normalization are given to AI algorithms for presenting and evaluating in this paper. Different AI techniques are then utilized to compare which identification algorithms are suitable to diagnose the SLGF for various power signatures in a NIFM system. The simulation results show that the proposed method is effective and can identify the fault locations by using non-intrusive monitoring techniques for low voltage distribution systems. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Unsynchronized Phasor-Based Protection Method for Single Line-to-Ground Faults in an Ungrounded Offshore Wind Farm with Fully-Rated Converters-Based Wind Turbines
Energies 2017, 10(4), 526; https://doi.org/10.3390/en10040526
Received: 12 December 2016 / Revised: 14 March 2017 / Accepted: 10 April 2017 / Published: 13 April 2017
Cited by 1 | PDF Full-text (3654 KB) | HTML Full-text | XML Full-text
Abstract
This paper proposes a protection method for single line-to-ground (SLG) faults in an ungrounded offshore wind farm with fully-rated converter-based wind turbines. The proposed method uses the unsynchronized current phasors measured by unit protections installed at the connection point of the fully-rated converter [...] Read more.
This paper proposes a protection method for single line-to-ground (SLG) faults in an ungrounded offshore wind farm with fully-rated converter-based wind turbines. The proposed method uses the unsynchronized current phasors measured by unit protections installed at the connection point of the fully-rated converter (FRC)-based wind turbines (WTs). Each unit protection collects the unsynchronized current phasors from two adjacent nodes and synchronizes them by aligning the positive-sequence current to the same phase angle. The faulted section is identified by comparing the phase angles of the synchronized zero-sequence currents from adjacent nodes. Simulations of an ungrounded offshore wind farm with relay models were carried out using power system computer-aided design (PSCAD)/ electromagnetic transients including direct current (EMTDC). Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Research on Stochastic Optimal Operation Strategy of Active Distribution Network Considering Intermittent Energy
Energies 2017, 10(4), 522; https://doi.org/10.3390/en10040522
Received: 30 January 2017 / Revised: 28 March 2017 / Accepted: 30 March 2017 / Published: 12 April 2017
Cited by 8 | PDF Full-text (16385 KB) | HTML Full-text | XML Full-text
Abstract
Active distribution networks characterized by high flexibility and controllability are an important development mode of future smart grids to be interconnected with large scale distributed generation sources including intermittent energies. However, the uncertainty of intermittent energy and the diversity of controllable devices make [...] Read more.
Active distribution networks characterized by high flexibility and controllability are an important development mode of future smart grids to be interconnected with large scale distributed generation sources including intermittent energies. However, the uncertainty of intermittent energy and the diversity of controllable devices make the optimal operation of distribution network a challenging issue. In this paper, we propose a stochastic optimal operation strategy for distribution networks with the objective function considering the operation state of the distribution network. Both distributed generations and flexible loads are taken into consideration in our strategy. The uncertainty of the intermittent energy is considered in this paper to obtain an optimized operation and an efficient utilization of intermittent energy under the worst scenario. Then, Benders decomposition is used in this paper to solve the two-stage max-min problem for stochastic optimal operation. Finally, we test the effectiveness of our strategy under different scenarios of the demonstration project of active distribution network located in Guizhou, China. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
EMTP Model of a Bidirectional Cascaded Multilevel Solid State Transformer for Distribution System Studies
Energies 2017, 10(4), 521; https://doi.org/10.3390/en10040521
Received: 30 January 2017 / Revised: 10 March 2017 / Accepted: 10 April 2017 / Published: 12 April 2017
Cited by 5 | PDF Full-text (11762 KB) | HTML Full-text | XML Full-text
Abstract
Abstract: This paper presents a time-domain model of a MV/LV bidirectional solid state transformer (SST). A multilevel converter configuration of the SST MV side is obtained by cascading a single-phase cell made of the series connection of an H bridge and a [...] Read more.
Abstract: This paper presents a time-domain model of a MV/LV bidirectional solid state transformer (SST). A multilevel converter configuration of the SST MV side is obtained by cascading a single-phase cell made of the series connection of an H bridge and a dual active bridge (dc-dc converter); the aim is to configure a realistic SST design suitable for MV levels. A three-phase four-wire converter has been used for the LV side, allowing the connection of both load/generation. The SST model, including the corresponding controllers, has been built and encapsulated as a custom-made model in the ATP version of the EMTP for application in distribution system studies. Several case studies have been carried out in order to evaluate the behavior of the proposed SST design under different operating conditions and check its impact on power quality. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
A Highly Relevant Method for Incorporation of Shunt Connected FACTS Device into Multi-Machine Power System to Dampen Electromechanical Oscillations
Energies 2017, 10(4), 482; https://doi.org/10.3390/en10040482
Received: 18 January 2017 / Revised: 26 March 2017 / Accepted: 29 March 2017 / Published: 4 April 2017
Cited by 2 | PDF Full-text (3493 KB) | HTML Full-text | XML Full-text
Abstract
A number of techniques have been proposed to dampen the power system oscillations in the electric power systems. Flexible alternating current transmission system (FACTS) devices are becoming one of them. Among the FACTS family, the static synchronous compensator (STATCOM), a shunt connected FACTS [...] Read more.
A number of techniques have been proposed to dampen the power system oscillations in the electric power systems. Flexible alternating current transmission system (FACTS) devices are becoming one of them. Among the FACTS family, the static synchronous compensator (STATCOM), a shunt connected FACTS device, has been widely used to provide smooth and rapid steady state, limit transient voltage, and improve the power system stability and performance by absorbing or injecting reactive power. However, the influence ability depends on its placement, control signal, and place of receiving-signal in the network. In order to satisfy these issues, this paper proposes a method for optimal setting and signal position of the STATCOM into the multi-machine power systems with the aim for damping the electromechanical oscillations. This method is developed from the energy approach based on Gramian matrices considering multiple tasks on the Lyapunov equation, in which the observability Gramian matrix is used to seek an optimal location for STATCOM placement. The another is the controllability one used to determine the best local input signal placement that is chosen as a feedback signal for the power oscillation damping (POD) of STATCOM. In addition, the Krylov-based model reduction method is introduced to shorten the calculation time. The proposed method has been verified on the IEEE 24-bus system by analyzing the small-signal stability to search several feasible placements, and then the transient stability is analyzed to compare and determine an optimal placement through testing various cases. The obtained result is also compared with other optimal method. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Measurement of Line-to-Ground Capacitance in Distribution Network Considering Magnetizing Impedance’s Frequency Characteristic
Energies 2017, 10(4), 477; https://doi.org/10.3390/en10040477
Received: 1 February 2017 / Revised: 21 March 2017 / Accepted: 27 March 2017 / Published: 3 April 2017
Cited by 1 | PDF Full-text (2443 KB) | HTML Full-text | XML Full-text
Abstract
Signal injection method (SIM) is widely applied to the insulation parameters’ measurement in distribution network for its convenience and safety. It can be divided into two kinds of patterns: injecting a specific frequency signal or several frequencies’ groups, and scanning frequency in a [...] Read more.
Signal injection method (SIM) is widely applied to the insulation parameters’ measurement in distribution network for its convenience and safety. It can be divided into two kinds of patterns: injecting a specific frequency signal or several frequencies’ groups, and scanning frequency in a scheduled frequency scope. In order to avoid the disadvantages in related researches, improved signal injection method (ISIM), in which the frequency characteristic of the transformer magnetizing impedance is taken into consideration, is proposed. In addition, optimization for signal injection position has been accomplished, and the corresponding three calculation methods of line-to-ground capacitance has been derived. Calculations are carried out through the vector information (vector calculation method), the amplitude information (amplitude calculation method), the phase information (phase calculation method) of voltage and current in signal injecting port, respectively. The line-to-ground capacitance is represented by lumped parameter capacitances in high-voltage simulation test. Eight different sinusoidal signals are injected into zero-sequence circuit, and then line-to-ground capacitance is calculated with the above-mentioned vector calculation method based on the voltage and the current data of the injecting port. The results obtained by the vector calculation method show that ISIM has a wider application frequency range compared with signal injection method with rated parameters (RSIM) and SIM. The RSIM is calculated with the rated transformer parameters of magnetizing impedance, and the SIM based on the ideal transformer model, and the relative errors of calculation results of ISIM are smaller than that for other methods in general. The six groups of two-frequency set are chosen in a specific scope which is recommended by vector calculation results. Based on ISIM, the line-to-ground capacitance calculations through the amplitude calculation method and phase calculation method are compared, and then its application frequency range, which can work as a guidance for line-to-ground capacitance measurement, is concluded. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Comparison of Impulse Wave and Sweep Frequency Response Analysis Methods for Diagnosis of Transformer Winding Faults
Energies 2017, 10(4), 431; https://doi.org/10.3390/en10040431
Received: 27 January 2017 / Revised: 13 March 2017 / Accepted: 20 March 2017 / Published: 28 March 2017
Cited by 7 | PDF Full-text (5569 KB) | HTML Full-text | XML Full-text
Abstract
Monitoring of winding faults is the most important item used to determine the maintenance status of a transformer. Commonly used methods for winding-fault diagnosis require the transformer to exit operation before testing and an external exciting signal, whether the transformer is malfunctioning or [...] Read more.
Monitoring of winding faults is the most important item used to determine the maintenance status of a transformer. Commonly used methods for winding-fault diagnosis require the transformer to exit operation before testing and an external exciting signal, whether the transformer is malfunctioning or not. However, if an overvoltage signal can be regarded as a broadband excitation source for fault diagnosis, then the interference caused by signal injection can be eliminated without the need for additional pulse or impulse signals. In this paper, a tapped transformer is designed and test platforms are built to compare winding diagnoses using the impulse wave and sweep frequency response analysis methods by recording voltage responses on both the high- and low-voltage sides and calculating the respective transfer functions. Based on comparison of statistical indicators, it is found that the sensitivities of both methods are similar for detecting conditions of winding-ground and winding-interlayer short circuits. It is concluded that it is feasible to use a transient overvoltage monitoring system for winding-fault diagnosis. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessEditor’s ChoiceArticle
Neuro-Fuzzy Wavelet Based Adaptive MPPT Algorithm for Photovoltaic Systems
Energies 2017, 10(3), 394; https://doi.org/10.3390/en10030394
Received: 2 February 2017 / Revised: 6 March 2017 / Accepted: 10 March 2017 / Published: 20 March 2017
Cited by 13 | PDF Full-text (5202 KB) | HTML Full-text | XML Full-text
Abstract
An intelligent control of photovoltaics is necessary to ensure fast response and high efficiency under different weather conditions. This is often arduous to accomplish using traditional linear controllers, as photovoltaic systems are nonlinear and contain several uncertainties. Based on the analysis of the [...] Read more.
An intelligent control of photovoltaics is necessary to ensure fast response and high efficiency under different weather conditions. This is often arduous to accomplish using traditional linear controllers, as photovoltaic systems are nonlinear and contain several uncertainties. Based on the analysis of the existing literature of Maximum Power Point Tracking (MPPT) techniques, a high performance neuro-fuzzy indirect wavelet-based adaptive MPPT control is developed in this work. The proposed controller combines the reasoning capability of fuzzy logic, the learning capability of neural networks and the localization properties of wavelets. In the proposed system, the Hermite Wavelet-embedded Neural Fuzzy (HWNF)-based gradient estimator is adopted to estimate the gradient term and makes the controller indirect. The performance of the proposed controller is compared with different conventional and intelligent MPPT control techniques. MATLAB results show the superiority over other existing techniques in terms of fast response, power quality and efficiency. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Stochastic Residential Harmonic Source Modeling for Grid Impact Studies
Energies 2017, 10(3), 372; https://doi.org/10.3390/en10030372
Received: 5 December 2016 / Revised: 19 February 2017 / Accepted: 7 March 2017 / Published: 17 March 2017
Cited by 2 | PDF Full-text (4859 KB) | HTML Full-text | XML Full-text
Abstract
With the introduction of more non-linear loads, e.g., compact fluorescent lamps, electric vehicles, photovoltaics, etc., the need to determine the harmonic impact of the residential load is rising, illustrated by the many studies performed on their harmonic impact. Traditionally, these studies are performed [...] Read more.
With the introduction of more non-linear loads, e.g., compact fluorescent lamps, electric vehicles, photovoltaics, etc., the need to determine the harmonic impact of the residential load is rising, illustrated by the many studies performed on their harmonic impact. Traditionally, these studies are performed for a single new device and single penetration level, neglecting the harmonic interaction between new types of devices, as well as giving little information at which moment in time possible problems may arise. A composite approach to access the impact of harmonic sources on the distribution network is therefore proposed. This method combines a bottom-up stochastic modeling of the residential load with harmonic measurement data and harmonic load-flows all based on a scenario analysis. The method is validated with measurement data and shows a good prediction of the current level of harmonics in a residential neighborhood for the current situation. To demonstrate the applicability of the proposed method, case studies are performed on the IEEE European Low Voltage Test Feeder. These case studies show a marked difference between applying individual device-based models and a composite modeling approach, demonstrating why the proposed approach is an adequate method for the determination of the impact of new devices on the harmonics. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Comprehensive Analysis of LCL Filter Interfaced Cascaded H-Bridge Multilevel Inverter-Based DSTATCOM
Energies 2017, 10(3), 346; https://doi.org/10.3390/en10030346
Received: 14 January 2017 / Revised: 28 February 2017 / Accepted: 7 March 2017 / Published: 12 March 2017
Cited by 5 | PDF Full-text (12209 KB) | HTML Full-text | XML Full-text
Abstract
Three-phase two-level voltage source converters are used for distribution static compensator (DSTATCOM) applications and can be replaced by a multilevel inverter. In this paper, an LCL filter interfaced cascaded H-bridge multilevel inverter-based (CHBMLI) DSTATCOM is simulated and its performance is analyzed considering the [...] Read more.
Three-phase two-level voltage source converters are used for distribution static compensator (DSTATCOM) applications and can be replaced by a multilevel inverter. In this paper, an LCL filter interfaced cascaded H-bridge multilevel inverter-based (CHBMLI) DSTATCOM is simulated and its performance is analyzed considering the system parameters. The analysis considers factors including the switching frequency, modulation index, and filter parameters of a DSTATCOM system. The LCL filter design and analysis for the low switching frequency operation of CHBMLI is proposed in this paper. Phase shift pulse-width modulation is used for the generation of switching signals. The reference current is generated using synchronous reference frame theory (SRFT) for reactive power and harmonic compensations. The simulation model of the CHBMLI-based DSTATCOM system is developed in MATLAB Simulink. The results are demonstrated for a linear/non-linear load under unbalanced conditions, considering the voltage sag and swell in the system due to a disturbance in the load. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Assessment of an Adaptive Load Forecasting Methodology in a Smart Grid Demonstration Project
Energies 2017, 10(2), 190; https://doi.org/10.3390/en10020190
Received: 23 November 2016 / Revised: 13 January 2017 / Accepted: 19 January 2017 / Published: 8 February 2017
Cited by 5 | PDF Full-text (3554 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents the implementation of an adaptive load forecasting methodology in two different power networks from a smart grid demonstration project deployed in the region of Madrid, Spain. The paper contains an exhaustive comparative study of different short-term load forecast methodologies, addressing [...] Read more.
This paper presents the implementation of an adaptive load forecasting methodology in two different power networks from a smart grid demonstration project deployed in the region of Madrid, Spain. The paper contains an exhaustive comparative study of different short-term load forecast methodologies, addressing the methods and variables that are more relevant to be applied for the smart grid deployment. The evaluation followed in this paper suggests that the performance of the different methods depends on the conditions of the site in which the smart grid is implemented. It is shown that some non-linear methods, such as support vector machine with a radial basis function kernel and extremely randomized forest offer good performance using only 24 lagged load hourly values, which could be useful when the amount of data available is limited due to communication problems in the smart grid monitoring system. However, it has to be highlighted that, in general, the behavior of different short-term load forecast methodologies is not stable when they are applied to different power networks and that when there is a considerable variability throughout the whole testing period, some methods offer good performance in some situations, but they fail in others. In this paper, an adaptive load forecasting methodology is proposed to address this issue improving the forecasting performance through iterative optimization: in each specific situation, the best short-term load forecast methodology is chosen, resulting in minimum prediction errors. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Contribution Determination for Multiple Unbalanced Sources at the Point of Common Coupling
Energies 2017, 10(2), 171; https://doi.org/10.3390/en10020171
Received: 8 December 2016 / Revised: 20 January 2017 / Accepted: 20 January 2017 / Published: 4 February 2017
Cited by 4 | PDF Full-text (1971 KB) | HTML Full-text | XML Full-text
Abstract
Three-phase unbalance is an important power quality issue that can cause many negative effects to the power system. Effective mitigation and management of voltage unbalance will benefit from the knowledge of how the unbalanced sources contribute to the voltage asymmetry at the point [...] Read more.
Three-phase unbalance is an important power quality issue that can cause many negative effects to the power system. Effective mitigation and management of voltage unbalance will benefit from the knowledge of how the unbalanced sources contribute to the voltage asymmetry at the point of evaluation (POE). In this paper, a method is proposed to assess the overall unbalance contribution of the multiple unbalanced sources at the point of common coupling (PCC). Firstly, the equivalent circuit for analysis is established and the unbalance contribution indices are proposed. Then a method is proposed to determine whether the dominant unbalanced polluter is at the upstream or downstream of POE. If the main unbalanced source is identified to be downstream of POE, a procedure is further proposed to determine the individual contribution of the multiple unbalanced sources. Moreover, for the multiple unbalanced source condition, the current flowing in each feeder is proposed to be used for the contribution estimation instead of the current actually emitted by the unbalanced source. Finally, a method is proposed to estimate the equivalent negative sequence impedance of the aggregate loads. Simulation and field analysis results validate the effectiveness and accuracy of the method. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
A Methodological Approach to Assess the Impact of Smarting Action on Electricity Transmission and Distribution Networks Related to Europe 2020 Targets
Energies 2017, 10(2), 155; https://doi.org/10.3390/en10020155
Received: 14 December 2016 / Revised: 13 January 2017 / Accepted: 19 January 2017 / Published: 26 January 2017
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Abstract
The achievement of the so-called 2020 targets requested by the European Union (EU) has determined a significant growth of proposals of solutions and of technical projects aiming at reducing the CO2 emissions and increasing the energy efficiency, as well as the penetration [...] Read more.
The achievement of the so-called 2020 targets requested by the European Union (EU) has determined a significant growth of proposals of solutions and of technical projects aiming at reducing the CO2 emissions and increasing the energy efficiency, as well as the penetration of Renewable Energy Sources (RES) in the electric network. As many of them ask for funding from the EU itself, there is the necessity to define a methodology to rank them and decide which projects should be sponsored to obtain the maximum effect on the EU 2020 targets. The present paper aims at (i) defining a set of Key Performance Indicators (KPIs) to compare different proposals, (ii) proposing an analytical methodology to evaluate the defined KPIs and (iii) evaluating the maximum impact that the considered action is capable of producing. The proposed methodology is applied to a set of possible interventions performed on a benchmark transmission network test case, in order to show that the defined indicators can be either calculated or measured and that they are useful to rank different “smarting actions”. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Energy Management Strategy Based on Multiple Operating States for a Photovoltaic/Fuel Cell/Energy Storage DC Microgrid
Energies 2017, 10(1), 136; https://doi.org/10.3390/en10010136
Received: 10 September 2016 / Revised: 2 January 2017 / Accepted: 13 January 2017 / Published: 21 January 2017
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Abstract
It is a great challenge for DC microgrids with stochastic renewable sources and volatility loads to achieve better operation performance. This study proposes an energy management strategy based on multiple operating states for a DC microgrid, which is comprised of a photovoltaic (PV) [...] Read more.
It is a great challenge for DC microgrids with stochastic renewable sources and volatility loads to achieve better operation performance. This study proposes an energy management strategy based on multiple operating states for a DC microgrid, which is comprised of a photovoltaic (PV) array, a proton exchange membrane fuel cell (PEMFC) system, and a battery bank. This proposed strategy can share the power properly and keep the bus voltage steady under different operating states (the state of charge (SOC) of the battery bank, loading conditions, and PV array output power). In addition, a microgrids test platform is established. In order to verify the effectiveness of the proposed energy management strategy, the strategy is implemented in a hardware system and experimentally tested under different operating states. The experimental results illustrate the good performance of the proposed control strategy for the DC microgrid under different scenarios of power generation and load demand. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
A Frequency Control Approach for Hybrid Power System Using Multi-Objective Optimization
Energies 2017, 10(1), 80; https://doi.org/10.3390/en10010080
Received: 9 November 2016 / Revised: 25 December 2016 / Accepted: 29 December 2016 / Published: 11 January 2017
Cited by 16 | PDF Full-text (2676 KB) | HTML Full-text | XML Full-text
Abstract
A hybrid power system uses many wind turbine generators (WTG) and solar photovoltaics (PV) in isolated small areas. However, the output power of these renewable sources is not constant and can diverge quickly, which has a serious effect on system frequency and the [...] Read more.
A hybrid power system uses many wind turbine generators (WTG) and solar photovoltaics (PV) in isolated small areas. However, the output power of these renewable sources is not constant and can diverge quickly, which has a serious effect on system frequency and the continuity of demand supply. In order to solve this problem, this paper presents a new frequency control scheme for a hybrid power system to ensure supplying a high-quality power in isolated areas. The proposed power system consists of a WTG, PV, aqua-electrolyzer (AE), fuel cell (FC), battery energy storage system (BESS), flywheel (FW) and diesel engine generator (DEG). Furthermore, plug-in hybrid electric vehicles (EVs) are implemented at the customer side. A full-order observer is utilized to estimate the supply error. Then, the estimated supply error is considered in a frequency domain. The high-frequency component is reduced by BESS and FW; while the low-frequency component of supply error is mitigated using FC, EV and DEG. Two PI controllers are implemented in the proposed system to control the system frequency and reduce the supply error. The epsilon multi-objective genetic algorithm ( ε -MOGA) is applied to optimize the controllers’ parameters. The performance of the proposed control scheme is compared with that of recent well-established techniques, such as a PID controller tuned by the quasi-oppositional harmony search algorithm (QOHSA). The effectiveness and robustness of the hybrid power system are investigated under various operating conditions. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
A Transient Fault Recognition Method for an AC-DC Hybrid Transmission System Based on MMC Information Fusion
Energies 2017, 10(1), 23; https://doi.org/10.3390/en10010023
Received: 29 August 2016 / Revised: 2 December 2016 / Accepted: 19 December 2016 / Published: 26 December 2016
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Abstract
At present, the research is still in the primary stage in the process of fault disturbance energy transfer in the multilevel modular converter based high voltage direct current (HVDC-MMC). An urgent problem is how to extract and analyze the fault features hidden in [...] Read more.
At present, the research is still in the primary stage in the process of fault disturbance energy transfer in the multilevel modular converter based high voltage direct current (HVDC-MMC). An urgent problem is how to extract and analyze the fault features hidden in MMC electrical information in further studies on the HVDC system. Aiming at the above, this article analyzes the influence of AC transient disturbance on electrical signals of MMC. At the same time, it is found that the energy distribution of electrical signals in MMC is different for different arms in the same frequency bands after the discrete wavelet packet transformation (DWPT). Renyi wavelet packet energy entropy (RWPEE) and Renyi wavelet packet time entropy (RWPTE) are proposed and applied to AC transient fault feature extraction from electrical signals in MMC. Using the feature extraction results of Renyi wavelet packet entropy (RWPE), a novel recognition method is put forward to recognize AC transient faults using the information fusion technology. Theoretical analysis and experimental results show that the proposed method is available to recognize transient AC faults. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Hybrid Short Term Wind Speed Forecasting Using Variational Mode Decomposition and a Weighted Regularized Extreme Learning Machine
Energies 2016, 9(12), 989; https://doi.org/10.3390/en9120989
Received: 3 August 2016 / Revised: 20 November 2016 / Accepted: 22 November 2016 / Published: 25 November 2016
Cited by 10 | PDF Full-text (6347 KB) | HTML Full-text | XML Full-text
Abstract
Accurate wind speed forecasting is a fundamental element of wind power prediction. Thus, a new hybrid wind speed forecasting model, using variational mode decomposition (VMD), the partial autocorrelation function (PACF), and weighted regularized extreme learning machine (WRELM), is proposed to improve the accuracy [...] Read more.
Accurate wind speed forecasting is a fundamental element of wind power prediction. Thus, a new hybrid wind speed forecasting model, using variational mode decomposition (VMD), the partial autocorrelation function (PACF), and weighted regularized extreme learning machine (WRELM), is proposed to improve the accuracy of wind speed forecasting. First, the historic wind speed time series is decomposed into several intrinsic mode functions (IMFs). Second, the partial correlation of each IMF sequence is analyzed using PACF to select the optimal subfeature set for particular predictors of each IMF. Then, the predictors of each IMF are constructed in order to enhance its strength using WRELM. Finally, wind speed is obtained by adding up all the predictors. The experiment, using real wind speed data, verified the effectiveness and advancement of the new approach. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Scenario Analysis of Carbon Emissions of China’s Electric Power Industry Up to 2030
Energies 2016, 9(12), 988; https://doi.org/10.3390/en9120988
Received: 28 October 2016 / Revised: 20 November 2016 / Accepted: 22 November 2016 / Published: 25 November 2016
Cited by 9 | PDF Full-text (1166 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, the Long-range Energy Alternatives Planning (LEAP) model is constructed to simulate six scenarios for forecasting national electricity demand in China. The results show that in 2020 the total electricity demand will reach 6407.9~7491.0 billion KWh, and will be 6779.9~10,313.5 billion [...] Read more.
In this paper, the Long-range Energy Alternatives Planning (LEAP) model is constructed to simulate six scenarios for forecasting national electricity demand in China. The results show that in 2020 the total electricity demand will reach 6407.9~7491.0 billion KWh, and will be 6779.9~10,313.5 billion KWh in 2030. Moreover, under the assumption of power production just meeting the social demand and considering the changes in the scale and technical structure of power industry, this paper simulates two scenarios to estimate carbon emissions and carbon intensity till 2030, with 2012 as the baseline year. The results indicate that the emissions intervals are 4074.16~4692.52 million tCO2 in 2020 and 3948.43~5812.28 million tCO2 in 2030, respectively. Carbon intensity is 0.63~0.64 kg CO2/KWh in 2020 and 0.56~0.58 kg CO2/KWh in 2030. In order to accelerate carbon reduction, the future work should focus on making a more stringent criterion on the intensity of industrial power consumption and expanding the proportion of power generation using clean energy, large capacity, and high efficiency units. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Analysis of Power Network for Line Reactance Variation to Improve Total Transmission Capacity
Energies 2016, 9(11), 936; https://doi.org/10.3390/en9110936
Received: 25 July 2016 / Revised: 29 September 2016 / Accepted: 2 November 2016 / Published: 10 November 2016
Cited by 4 | PDF Full-text (3349 KB) | HTML Full-text | XML Full-text
Abstract
The increasing growth in power demand and the penetration of renewable distributed generations in competitive electricity market demands large and flexible capacity from the transmission grid to reduce transmission bottlenecks. The bottlenecks cause transmission congestion, reliability problems, restrict competition, and limit the maximum [...] Read more.
The increasing growth in power demand and the penetration of renewable distributed generations in competitive electricity market demands large and flexible capacity from the transmission grid to reduce transmission bottlenecks. The bottlenecks cause transmission congestion, reliability problems, restrict competition, and limit the maximum dispatch of low cost generations in the network. The electricity system requires efficient utilization of the current transmission capability to improve the Available Transfer Capability (ATC). To improve the ATC, power flow among the lines can be managed by using Flexible AC Transmission System (FACTS) devices as power flow controllers, which alter the parameters of power lines. It is important to place FACTS devices on suitable lines to vary the reactance for improving Total Transmission Capacity (TTC) of the network and provide flexibility in the power flow. In this paper a transmission network is analyzed based on line parameters variation to improve TTC of the interconnected system. Lines are selected for placing FACTS devices based on real power flow Performance Index (PI) sensitivity factors. TTC is computed using the Repeated Power Flow (RPF) method using the constraints of lines thermal limits, bus voltage limits and generator limits. The reactance of suitable lines, selected on the basis of PI sensitivity factors are changed to divert the power flow to other lines with enough transfer capacity available. The improvement of TTC using line reactance variation is demonstrated with three IEEE test systems with multi-area networks. The results show the variation of the selected lines’ reactance in improving TTC for all the test networks with defined contingency cases. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
New Requirements of the Voltage/VAR Function for Smart Inverter in Distributed Generation Control
Energies 2016, 9(11), 929; https://doi.org/10.3390/en9110929
Received: 19 July 2016 / Revised: 19 October 2016 / Accepted: 4 November 2016 / Published: 9 November 2016
Cited by 6 | PDF Full-text (2527 KB) | HTML Full-text | XML Full-text
Abstract
International Electronical Committee (IEC) 61850-90-7 is a part of the IEC 61850 series which specifies the advanced functions and object models for power converter based Distributed Energy Resources (DERs). One of its functions, the Voltage/VAR (V/V) control function, is used to enhance the [...] Read more.
International Electronical Committee (IEC) 61850-90-7 is a part of the IEC 61850 series which specifies the advanced functions and object models for power converter based Distributed Energy Resources (DERs). One of its functions, the Voltage/VAR (V/V) control function, is used to enhance the stability and the reliability of the voltage in the distribution system. The conventional V/V function acts mainly for flattening the voltage profile as for a basic grid support function. Currently, other objectives such as the minimization of line loss and the operational costs reduction are coming into the spotlight. In order to attain these objectives, the V/V function and hence the DER units shall actively respond to the change of distribution system conditions. In this paper, the modification of V/V function and new requirements are proposed. To derive new requirements of V/V function, loss minimization is applied to a particle swarm optimization (PSO) algorithm where the condition of voltage constraint is considered not to deteriorate the voltage stability of the distribution system. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Using Trajectory Clusters to Define the Most Relevant Features for Transient Stability Prediction Based on Machine Learning Method
Energies 2016, 9(11), 898; https://doi.org/10.3390/en9110898
Received: 28 July 2016 / Revised: 25 October 2016 / Accepted: 25 October 2016 / Published: 1 November 2016
Cited by 7 | PDF Full-text (3691 KB) | HTML Full-text | XML Full-text
Abstract
To achieve rapid real-time transient stability prediction, a power system transient stability prediction method based on the extraction of the post-fault trajectory cluster features of generators is proposed. This approach is conducted using data-mining techniques and support vector machine (SVM) models. First, the [...] Read more.
To achieve rapid real-time transient stability prediction, a power system transient stability prediction method based on the extraction of the post-fault trajectory cluster features of generators is proposed. This approach is conducted using data-mining techniques and support vector machine (SVM) models. First, the post-fault rotor angles and generator terminal voltage magnitudes are considered as the input vectors. Second, we construct a high-confidence dataset by extracting the 27 trajectory cluster features obtained from the chosen databases. Then, by applying a filter–wrapper algorithm for feature selection, we obtain the final feature set composed of the eight most relevant features for transient stability prediction, called the global trajectory clusters feature subset (GTCFS), which are validated by receiver operating characteristic (ROC) analysis. Comprehensive simulations are conducted on a New England 39-bus system under various operating conditions, load levels and topologies, and the transient stability predicting capability of the SVM model based on the GTCFS is extensively tested. The experimental results show that the selected GTCFS features improve the prediction accuracy with high computational efficiency. The proposed method has distinct advantages for transient stability prediction when faced with incomplete Wide Area Measurement System (WAMS) information, unknown operating conditions and unknown topologies and significantly improves the robustness of the transient stability prediction system. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Nonlinear Coupled Dynamics of a Rod Fastening Rotor under Rub-Impact and Initial Permanent Deflection
Energies 2016, 9(11), 883; https://doi.org/10.3390/en9110883
Received: 22 August 2016 / Revised: 18 October 2016 / Accepted: 24 October 2016 / Published: 28 October 2016
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Abstract
A nonlinear coupled dynamic model of a rod fastening rotor under rub-impact and initial permanent deflection was developed in this paper. The governing motion equation was derived by the D’Alembert principle considering the contact characteristic between disks, nonlinear oil-film force, rub-impact force, unbalance [...] Read more.
A nonlinear coupled dynamic model of a rod fastening rotor under rub-impact and initial permanent deflection was developed in this paper. The governing motion equation was derived by the D’Alembert principle considering the contact characteristic between disks, nonlinear oil-film force, rub-impact force, unbalance mass, etc. The contact effects between disks was modeled as a flexural spring with cubical nonlinear stiffness. The coupled nonlinear dynamic phenomena of the rub-impact rod fastening rotor bearing system with initial permanent deflection were investigated by the fourth-order Runge-Kutta method. Bifurcation diagram, vibration waveform, frequency spectrum, shaft orbit and Poincaré map are used to illustrate the rich diversity of the system response with complicated dynamics. The studies indicate that the coupled dynamic responses of the rod fastening rotor bearing system under rub-impact and initial permanent deflection exhibit a rich nonlinear dynamic diversity, synchronous periodic-1 motion, multiple periodic motion, quasi-periodic motion and chaotic motion can be observed under certain conditions. Larger radial stiffness of the stator will simplify the system motion and make the oil whirl weaker or even disappear at a certain rotating speed. With the increase of initial permanent deflection length, the instability speed of the system gradually rises, and the chaotic motion region gets smaller and smaller. The corresponding results can provide guidance for the fault diagnosis of a rub-impact rod fastening rotor with initial permanent deflection and contribute to the further understanding of the nonlinear dynamic characteristics of the rod fastening rotor bearing system. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Accuracy Enhancement of Mixed Power Flow Analysis Using a Modified DC Model
Energies 2016, 9(10), 776; https://doi.org/10.3390/en9100776
Received: 1 August 2016 / Revised: 9 September 2016 / Accepted: 22 September 2016 / Published: 26 September 2016
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Abstract
The mixed power flow analysis method decreases the computational complexity and achieves a high level of simulation accuracy. The mixed approach combines the ac with the dc power flow models, depending on the area of interest. The accurate ac model is used in [...] Read more.
The mixed power flow analysis method decreases the computational complexity and achieves a high level of simulation accuracy. The mixed approach combines the ac with the dc power flow models, depending on the area of interest. The accurate ac model is used in the study area of interest to obtain high simulation accuracy, while the approximate dc model is used in the remainder of the system to reduce the required computations. In the original mixed approach, the errors originating from the use of the dc model may propagate to the area of interest where accurate simulation outcomes are required; thus, the simulation accuracy might not be satisfactory. This paper presents a new method of enhancing the simulation accuracy of the mixed power flow analysis using available information. In the proposed approach, a modified dc model is used instead of the traditional one and is constructed from an initial base-case ac solution. The new dc model compensates for the errors originating from the neglect of the real power losses and the assumption of a flat voltage magnitude in the conventional dc model. Thus, the proposed method can improve the simulation accuracy in the area of interest. The superior computational benefits can also be preserved by maintaining linear characteristics of the dc model. Case studies with the IEEE 118-bus system are provided to validate the enhanced accuracy of the proposed method. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
Optimal Power Flow Using the Jaya Algorithm
Energies 2016, 9(9), 678; https://doi.org/10.3390/en9090678
Received: 7 July 2016 / Revised: 7 August 2016 / Accepted: 19 August 2016 / Published: 25 August 2016
Cited by 32 | PDF Full-text (3298 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents application of a new effective metaheuristic optimization method namely, the Jaya algorithm to deal with different optimum power flow (OPF) problems. Unlike other population-based optimization methods, no algorithm-particular controlling parameters are required for this algorithm. In this work, three goal [...] Read more.
This paper presents application of a new effective metaheuristic optimization method namely, the Jaya algorithm to deal with different optimum power flow (OPF) problems. Unlike other population-based optimization methods, no algorithm-particular controlling parameters are required for this algorithm. In this work, three goal functions are considered for the OPF solution: generation cost minimization, real power loss reduction, and voltage stability improvement. In addition, the effect of distributed generation (DG) is incorporated into the OPF problem using a modified formulation. For best allocation of DG unit(s), a sensitivity-based procedure is introduced. Simulations are carried out on the modified IEEE 30-bus and IEEE 118-bus networks to determine the effectiveness of the Jaya algorithm. The single objective optimization cases are performed both with and without DG. For all considered cases, results demonstrate that Jaya algorithm can produce an optimum solution with rapid convergence. Statistical analysis is also carried out to check the reliability of the Jaya algorithm. The optimal solution obtained by the Jaya algorithm is compared with different stochastic algorithms, and demonstrably outperforms them in terms of solution optimality and solution feasibility, proving its effectiveness and potential. Notably, optimal placement of DGs results in even better solutions. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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Open AccessArticle
DC-Link Capacitor Voltage Regulation for Three-Phase Three-Level Inverter-Based Shunt Active Power Filter with Inverted Error Deviation Control
Energies 2016, 9(7), 533; https://doi.org/10.3390/en9070533
Received: 16 May 2016 / Revised: 16 June 2016 / Accepted: 4 July 2016 / Published: 12 July 2016
Cited by 16 | PDF Full-text (10208 KB) | HTML Full-text | XML Full-text
Abstract
A new control technique known as inverted error deviation (IED) control is incorporated into the main DC-link capacitor voltage regulation algorithm of a three-level neutral-point diode clamped (NPC) inverter-based shunt active power filter (SAPF) to enhance its performance in overall DC-link voltage regulation [...] Read more.
A new control technique known as inverted error deviation (IED) control is incorporated into the main DC-link capacitor voltage regulation algorithm of a three-level neutral-point diode clamped (NPC) inverter-based shunt active power filter (SAPF) to enhance its performance in overall DC-link voltage regulation so as to improve its harmonics mitigation performances. In the SAPF controller, DC-link capacitor voltage regulation algorithms with either the proportional-integral (PI) or fuzzy logic control (FLC) technique have played a significant role in maintaining a constant DC-link voltage across the DC-link capacitors. However, both techniques are mostly operated based on a direct voltage error manipulation approach which is insufficient to address the severe DC-link voltage deviation that occurs during dynamic-state conditions. As a result, the conventional algorithms perform poorly with large overshoot, undershoot, and slow response time. Therefore, the IED control technique is proposed to precisely address the DC-link voltage deviation. To validate effectiveness and feasibility of the proposed algorithm, simulation work in MATLAB-Simulink and experimental implementation utilizing a TMS320F28335 Digital Signal Processor (DSP) are performed. Moreover, conventional algorithms with PI and FLC techniques are tested too for comparison purposes. Both simulation and experimental results are presented, confirming the improvement achieved by the proposed algorithm in terms of accuracy and dynamic response in comparison to the conventional algorithms. Full article
(This article belongs to the Special Issue Electric Power Systems Research 2017)
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