# Optimal Operation and Management of Smart Grid System with LPC and BESS in Fault Conditions

^{*}

^{†}

## Abstract

**:**

## 1. Introduction

- Case 1: BESS management is provided; the simulation can be divided into two operation modes. One operation is the normal operation, which is optimized from the loss reduction aspects. The second mode provides continuous power supply in a disconnected fault situation.
- Case 2: An LPC reconfiguration system is proven to supply energy in an outage. In terms of a fault, electrical power is supplied from the installed DGs, and an optimized reconfiguration is demonstrated in some configurations.
- Case 3: The smart grid with the adopted LPC can be seen as an active smart grid system; the active smart grid is reconstituted in order to minimize distribution losses in real time.

## 2. Reliability and Stable Power Supply

## 3. Control Devices and Configuration

#### 3.1. LRT and SVRs

#### 3.2. BESS

#### 3.3. PV System

#### 3.4. LPC

#### 3.5. Home BESS

## 4. Formulation of the Modeling and Optimization Method

#### 4.1. Modeling of the Distribution System

#### 4.1.1. The Objective Function and Constraints

#### Objective Function

#### Constraints

## 5. Adaptive Inertia Weight PSO Method for the Decision Making of the Optimal Operation Schedule

#### 5.1. Particle Swarm Optimization

- Step 1:
- Generate an initial searching point for each swarm.
- Step 2:
- Evaluate the objective function using each swarm’s searching point.
- Step 3:
- Finish searching if the stopping conditions are satisfied. If not, go to Step 4.
- Step 4:
- Search the next point considering the best of the current swarm’s searching points, as well as each swarm’s best searching point. Go to Step 2.

#### 5.2. Flexible Inertia Strategy of PSO

#### 5.3. Scheduling Method for Reconfiguration

## 6. Simulation Results

#### 6.1. Simulation Model

- Case 1:
- BESS 1 is installed at the interconnection point to protect the upper high voltage system from reverse power flow. BESS 2 is installed in a branched office area as an emergency energy storage. In this case, BESS management is simulated in two modes of operation: operation Mode 1 is normal operation without a fault. On the other hand, when a disconnection fault occurs in the office area of Figure 6, islanding is applied by using BESS 2 as a power supply. As control devices for active and reactive power supply, BESS 1, BESS 2, LRT, SVR, SVC and inverters interfacing with the PVs are used. The results of each mode in Case 1 are provided in Figure 7 and Figure 8.
- Case 2:
- In this case, LPCs are installed instead of BESSs in a fault situation. Moreover, the home BESS is introduced in DG nodes to supply reactive power. A three line disconnection fault will be considered. The fault locations and some examples of active smart grid configurations are shown in Figure 9 and Figure 10, respectively. The comparison of active smart grid is presented as Figure 11, Figure 12, and Table 3. To note this case, LPCs run only in fault conditions.
- Case 3:
- The six LPCs are installed in the smart grid system as shown in Figure 13. Case 3 is different from Case 2 in that the system configuration will be changed in real time as a one-hour step. A reconfiguration operation of the active smart grid is optimized to minimize distribution losses. In order to solve the complex optimization including CP, a dual scheduling method is applied to the system.

#### 6.2. Case Studies

#### 6.2.1. Case 1: BESSs Management

#### 6.2.2. Case 2: Prevention of Local Outage by LPC Operation

#### 6.2.3. Case 3: Optimal Active Smart Grid System Design Using LPCs

## 7. Conclusions

## Author Contributions

## Conflicts of Interest

## Nomenclature

AIW | Adaptive inertia weight |

BESS | Battery energy storage system |

CP | Combinatorial problem |

DG | Distributed generator |

DisCo | Distribution company |

EV | Electric vehicle |

LRT | Load ratio transformer |

MPPT | Maximum power point tracking |

NAS | Liquid sodium (Na) and sulfur (S) |

PSO | Particle swarm optimization |

PV | Photovoltaic |

RES | Renewable energy source |

SOC | State of charge |

SVC | Static var compensator |

SVR | Step voltage regulator |

WG | Wind turbine generator |

η | Charging and discharging efficiency of large BESS. |

$\mathbb{L}$ | LPCs connection set. |

ζ | SOC of house BESSs, BESS and EVs. |

${B}_{ki}$ | Imaginary part of admittance ${Y}_{ki}$. |

${c}_{1}$ | Weight for the position of the current best particle. |

${c}_{2}$ | Weight for the best position of the particle swarm. |

${C}_{LB}$ | Capacity of large BESS. |

${G}_{ki}$ | Real part of admittance ${Y}_{ki}$. |

$gbest$ | Best position of the particle swarm. |

${m}_{i}$ | Adjustment value of the inertia weight at generation h. |

${n}_{h}$ | Particle number n at generation h. |

${N}_{node}$ | Node number of the distribution system. |

${P}_{f}$ | Active power flow at the interconnection point. |

${P}_{f}^{min},{P}_{f}^{max}$ | Lower and upper limit of the active power flow at the interconnection point. |

${P}_{k}^{G}$ | Active power from the k node generator. |

${P}_{k}^{L}$ | Load demand at the k node. |

${P}_{LBinv}^{*}$ | Order value of the active power output of BESS from DisCo. |

${P}_{LBinv}^{min},{P}_{LBinv}^{max}$ | Lower and upper limit of the active power of large BESS inverter. |

${P}_{LB}$ | Active power output of large BESS. |

${P}_{Li}$ | Distribution loss at node i. |

${P}_{Loss,i}$ | Active power loss of node i. |

${P}_{PVinv}$ | Active power output from the PV generator system. |

${P}_{PV}$ | Active power output from the PV panel. |

$pbest$ | Position of the current best particle. |

${Q}_{DRm}$ | Reactive power output of inverters interfaced with home BESS. |

${Q}_{DRm}^{min},{Q}_{DRm}^{max}$ | Lower and upper limit of the home battery inverter regarding reactive power output. |

${Q}_{f}$ | Reactive power flow at the interconnection point. |

${Q}_{f}^{min},{Q}_{f}^{max}$ | Lower and upper limit of the reactive power flow at the interconnection point. |

${Q}_{k}^{G}$ | Reactive power from the k node generator. |

${Q}_{k}^{L}$ | Load demand at the k node. |

${Q}_{LBinv}$ | Reactive power output of large BESS. |

${Q}_{LBinv}^{*}$ | Order value of the reactive power output of BESS from DisCo. |

${Q}_{LBinv}^{min},{Q}_{LBinv}^{max}$ | Lower and upper limit of the reactive power output of large BESS inverter. |

${Q}_{PVinv}$ | Reactive power output of inverters interfaced with PV. |

${Q}_{PVinv}^{*}$ | Order value of reactive power. |

${Q}_{PVinv}^{min},{Q}_{PVinv}^{max}$ | Lower and upper limit of the PV inverter regarding reactive power output. |

${R}_{ki}$ | Resistance between node k and i. |

$ran{d}_{1}$ | Uniform random numbers from 0–1. |

${S}_{h+1}$ | Search position of the i-th particle in the h-th search. |

${S}_{LBinv}$ | Inverter capacity of large BESS. |

${S}_{PVinv}$ | Inverter capacity of the PV inverter. |

t | Time step at optimization. |

${T}_{k}$ | Tap positions of LRT and SVR. |

${T}_{k}^{min},{T}_{k}^{max}$ | Lower and upper tap limit of LRT and SVRs. |

${V}_{h+1}\left(i\right)$ | i-th particle velocity in the $h+1$-th search. |

${V}_{min},{V}_{max}$ | Minimum and maximum of the voltage constraints. |

${V}_{m}$ | Node voltage at node m. |

w | Weight of inertia. |

${w}_{i}$ | Updated inertia weight value. |

## References

- Han, J.; Sic Choi, C.; Park, W.-K.; Lee, I.; Kim, S.-H. Smart home energy management system including renewable energy based on zigbee and plc. IEEE Trans. Consum. Electron.
**2014**, 60, 198–202. [Google Scholar] [CrossRef] - Smith, J.; Sunderman, W.; Dugan, R.; Seal, B. Smart inverter volt/var control functions for high penetration of pv on distribution systems. In Proceedings of the 2011 IEEE/PES Power Systems Conference and Exposition (PSCE), Phoenix, AZ, USA, 20–23 March 2011; pp. 1–6.
- Tsubasa, S.; Hayato, T.; Hidehito, M.; Atsushi, Y.; Tomonobu, S. Comparison and Validation of Operational Cost in Smart Houses with the Introduction of a Heat Pump or a Gas Engine. Int. J. Emerg. Electr. Power Syst.
**2015**, 16, 59–74. [Google Scholar] - Shimoji, T.; Tahara, H.; Matayoshi, H.; Yona, A.; Senjyu, T. Optimal Scheduling Method of Controllable Loads in DC Smart Apartment Building. Int. J. Emerg. Electr. Power Syst.
**2015**, 16, 579–589. [Google Scholar] [CrossRef] - Howlader, H.O.R.; Matayoshi, H.; Senjyu, T. Thermal Units Commitment Integrated with Reactive Power Scheduling for the Smart Grid Considering Voltage Constraints. Int. J. Emerg. Electr. Power Syst.
**2015**, 16, 323–330. [Google Scholar] [CrossRef] - Woyte, A.; van Thong, V.; Belmans, R.; Nijs, J. Voltage fluctuations on distribution level introduced by photovoltaic systems. IEEE Trans. Energy Convers.
**2006**, 21, 202–209. [Google Scholar] [CrossRef] - Iyer, S.V.; Wu, B.; Li, Y.; Singh, B. A Mathematical Model to Predict Voltage Fluctuations in a Distribution System with Renewable Energy Sources. Int. J. Emerg. Electr. Power Syst.
**2015**, 16, 549–557. [Google Scholar] [CrossRef] - Rao, B.N.; Abhyankar, A.R.; Nilanjan, S. DG Planning with Amalgamation of Operational and Reliability Considerations. Int. J. Emerg. Electr. Power Syst.
**2016**, 17, 131–141. [Google Scholar] - Hojo, M.; Hatano, H.; Fuwa, Y. Voltage rise suppression by reactive power control with cooperating photovoltaic generation systems. In Proceedings of the 20th International Conference and Exhibition on Electricity Distribution—Part 2, CIRED 2009, Prague, Czech, 8–11 June 2009; p. 1.
- Hatta, H.; Uemura, S.; Kobayashi, H. Cooperative control of distribution system with customer equipments to reduce reverse power flow from distributed generation. In Proceedings of the 2010 IEEE Power and Energy Society General Meeting, Detroit, MI, USA, 24–28 July 2010; pp. 1–6.
- Ziadi, Z.; Taira, S.; Oshiro, M.; Funabashi, T. Optimal power scheduling for smart grids considering controllable loads and high penetration of photovoltaic generation. IEEE Trans. Smart Grid
**2014**, 5, 2350–2359. [Google Scholar] [CrossRef] - Zhang, M.; Chen, J. The energy management and optimized operation of electric vehicles based on microgrid. IEEE Trans. Power Deliv.
**2014**, 29, 1427–1435. [Google Scholar] [CrossRef] - Choudar, A.; Boukhetala, D.; Barkat, S.; Brucker, J.-M. A local energy management of a hybrid pv-storage based distributed generation for microgrids. Energy Convers. Manag.
**2015**, 90, 21–33. [Google Scholar] [CrossRef] - Momoh, J.A.; Reddy, S.S. Feasibility of Stochastic Voltage/VAr Optimization Considering Renewable Energy Resources for Smart Grid. Int. J. Emerg. Electr. Power Syst.
**2016**, 17, 287–300. [Google Scholar] [CrossRef] - Khederzadeh, M.; Khalili, M. High Penetration of Electrical Vehicles in Microgrids: Threats and Opportunities. Int. J. Emerg. Electr. Power Syst.
**2014**, 15, 457–469. [Google Scholar] [CrossRef] - Minh, B.D.; Shi-Lin, C.; Keng-Yu, L.; Jheng-Lun, J. A Generalised Fault Protection Structure Proposed for Uni-grounded Low-Voltage AC Microgrids. Int. J. Emerg. Electr. Power Syst.
**2016**, 17, 69–89. [Google Scholar] - Karan, S.; Bhalja, B.R.; Prakash, M.R. Evaluation of Superimposed Sequence Components of Currents based Islanding Detection Scheme during DG Interconnections. Int. J. Emerg. Electr. Power Syst.
**2016**, 17, 1–14. [Google Scholar] - Okada, N.; Kobayashi, H.; Takigawa, K.; Ichikawa, M.; Kurokawa, K. Loop power flow control and voltage characteristics of distribution system for distributed generation including pv system. In Proceedings of 3rd World Conference on Photovoltaic Energy Conversion, Osaka, Japan, 11–18 May 2003; Volume 3, pp. 2284–2287.
- Thatte, A.; Ilic, M. An assessment of reactive power/voltage control devices in distribution networks. In Proceedings of 2006 IEEE Power Engineering Society General Meeting, Montreal, QC, Canada, 18–22 June 2006; p. 8.
- Han, X.; Sandels, C.; Zhu, K.; Nordström, L. Modelling framework and the quantitative analysis of distributed energy resources in future distribution networks. Int. J. Emerg. Electr. Power Syst.
**2013**, 14, 421–431. [Google Scholar] [CrossRef][Green Version] - Reddy, S.S.; Hwan, L.Y. Optimum Location of Voltage Regulators in the Radial Distribution Systems. Int. J. Emerg. Electr. Power Syst.
**2016**, 17, 351–361. [Google Scholar] - Ryuto, S.; Samim, N.A.; Cirio, M.; Atsushi, Y.; Tomonobu, S. Optimal Operation and Management for Smart Grid Subsumed High Penetration of Renewable Energy, Electric Vehicle, and Battery Energy Storage System. Int. J. Emerg. Electr. Power Syst.
**2016**, 17, 173–189. [Google Scholar] - Wang, J.-C.; Chiang, H.-D.; Miu, K.; Darling, G. Capacitor placement and real time control in large-scale unbalanced distribution systems: loss reduction formula, problem formulation, solution methodology and mathematical justification. In Proceedings of the 1996 IEEE Transmission and Distribution Conference, Los Angeles, CA, USA, 15–20 September 1996; pp. 236–241.
- Roy, P.; Ghoshal, S.; Thakur, S. Optimal var control for improvements in voltage profiles and for real power loss minimization using biogeography based optimization. Int. J. Electr. Power Energy Syst.
**2012**, 43, 830–838. [Google Scholar] [CrossRef] - Song, I.-K.; Jung, W.-W.; Kim, J.-Y.; Yun, S.-Y.; Choi, J.-H.; Ahn, S.-J. Operation schemes of smart distribution networks with distributed energy resources for loss reduction and service restoration. IEEE Trans. Smart Grid
**2013**, 4, 367–374. [Google Scholar] [CrossRef] - Tomic, S. Economic effects of trading watts and negawatts by agile customers in hierarchic energy markets. In Proceedings of the 2012 9th International Conference on the European Energy Market (EEM), Florence, Italy, 10–12 May 2012; pp. 1–6.
- Mostafa, H.E.; El-Sharkawy, M.A.; Emary, A.A.; Yassin, K. Design and allocation of power system stabilizers using the particle swarm optimization technique for an interconnected power system. Int. J. Electr. Power Energy Syst.
**2012**, 34, 57–65. [Google Scholar] [CrossRef] - Al-Saedi, W.; Lachowicz, S.W.; Habibi, D.; Bass, O. Power quality enhancement in autonomous microgrid operation using particle swarm optimization. Int. J. Electr. Power Energy Syst.
**2012**, 42, 139–149. [Google Scholar] [CrossRef]

**Figure 7.**Simulation results of Case 1 without fault (operation Mode 1); all control devices’ operations are listed as: (

**a**) node voltage; (

**b**) reactive power output by inverters interfacing the PV; (

**c**) active power flow at the interconnection point; (

**d**) reactive power flow at the interconnection point; (

**e**) active power output of each large BESS; (

**f**) states of charge of each large BESS; (

**g**) reactive power output of BESS 1; (

**h**) reactive power output of BESS 2; and (

**i**) tap positions of the LRTs and SVRs.

**Figure 8.**Simulation results during fault in Case 1: (

**a**) node voltage; (

**b**) reactive power output of inverters interfacing the PVs; (

**c**) active power flow at the interconnection point; (

**d**) reactive power flow at the interconnection point; (

**e**) active power output of each large BESS; (

**f**) states of charge of each large BESS; (

**g**) reactive power output of BESS1; (

**h**) reactive power output of BESS2; and (

**i**) tap positions of LRT and SVRs.

**Figure 10.**Examples of the active smart grid system: (

**a**) end Node 16 is connected to end Node 35 in Case 2 (i); and (

**b**) end Node 16 is connected to end Node 24 of the office area in Case 2 (v).

**Figure 11.**Simulation results of Case 2 (0): (

**a**) node voltages; (

**b**) reactive power outputs from interfacing inverter of the PV; (

**c**) reactive power output by demand response; and (

**d**) tap positions of LRT and SVRs.

**Figure 12.**Simulation results considering a line fault in Case 2 (v): (

**a**) node voltages; (

**b**) reactive power output from the inverter interfacing the PV; (

**c**) reactive power output by demand response; (

**d**) tap position of LRT and SVRs; and (

**e**) comparison of distribution losses.

**Figure 14.**Examples of the distribution system configuration in Case 3 illustrated as: (

**a**) the reconstructed distribution model of Case 3 (i); and (

**b**) the reconstructed distribution model of Case 3 (vi) listed in Table 4.

**Figure 15.**Simulation results of Case 3 (vi): (

**a**) node voltages; (

**b**) reactive power output from the inverter interfacing the PV; (

**c**) reactive power output by demand response; and (

**d**) tap positions of LRT and SVRs. Note that the reconstruction distribution system of Case 3 (vi) represents the most reduced distribution losses.

**Figure 16.**Simulation results of the proposed method of Case 3: (

**a**) node voltages; (

**b**) reactive power output from inverter interfacing the PV; (

**c**) reactive power output by demand response; (

**d**) tap positions of LRT and SVRs; and (

**e**) comparison of distribution losses.

System or Installed Devices | Capacities |
---|---|

Line impedance at each section | $0.04+j0.04$ pu |

Rated capacity of PV nodes | $0.08$ pu (400 kW) |

Rated capacity of the inverter interfacing with the PV | $0.08$ pu (400 kW) |

Capacity of BESSs 1 and 2 | $5.0$ pu (25 MWh) |

Rated capacity of the inverter interfacing BESS 1 and BESS 2 | $0.4$ pu (2 MW) |

Simulation Contents | |
---|---|

Case 1 | BESS management in normal operation mode without fault (operation Mode 1). |

BESS management of emergency operation mode with disconnection fault (operation Mode 2). | |

Case 2 | Distribution loss analysis of local outage by disconnection fault. |

(LPCs are operated when an outage happens) | |

Case 3 | Reconfiguration management of active smart grid using LPCs. |

Make the decision of optimal operation throughout whole day. |

Simulation | Disconnected | Connecting Nodes | Time of Fault | Distribution Losses |
---|---|---|---|---|

Pattern | Area | by LPC | Occurrence | (kWh) |

Case 2 (0) | - | - | - | 652.2 |

Case 2 (i) | Nodes 14–31 | Nodes 16–35 | 14 o’clock | 1040 |

Case 2 (ii) | Nodes 24–35 | 1047 | ||

Case 2 (iii) | Nodes 12–21 | Nodes 16–24 | 707.5 | |

Case 2 (iv) | Nodes 35–24 | 631.8 | ||

Case 2 (v) | Nodes 12–13 | Nodes 16–24 | 438.5 | |

Case 2 (vi) | Nodes 35–24 | 603.5 | ||

Case 2 (vii) | Nodes 14–31 | Nodes 16–35 | 11 o’clock | 961.9 |

Case 2 (viii) | Nodes 24–35 | 993.6 | ||

Case 2 (ix) | Nodes 12–21 | Nodes 16–24 | 763.4 | |

Case 2 (x) | Nodes 35–24 | 893.9 | ||

Case 2 (xi) | Nodes 12–13 | Nodes 16–24 | 450.8 | |

Case 2 (xii) | Nodes 35–24 | 624.6 |

Simulation Pattern | Connecting LPCs | Distribution Losses (kWh) |
---|---|---|

Case 3 (i) | 1, 2, 3 | 652 |

Case 3 (ii) | 1, 2, 5 | 1343 |

Case 3 (iii) | 1, 2, 6 | 1490 |

Case 3 (iv) | 2, 3, 4 | 1128 |

Case 3 (v) | 2, 3, 6 | 1617 |

Case 3 (vi) | 1, 3, 4 | 450 |

Case 3 (vii) | 1, 3, 6 | 1116 |

Optimal reconfiguration schedule of active smart grid | |||||||||
---|---|---|---|---|---|---|---|---|---|

Time | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |

Distribution construction | (vi) | (i) | (i) | (i) | (i) | (vi) | (vi) | (i) | (i) |

Time | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 |

Distribution construction | (vi) | (vi) | (iv) | (vi) | (vi) | (iv) | (vi) | (vii) | (i) |

Time | 19 | 20 | 21 | 22 | 23 | 24 | Distribution losses | ||

Distribution construction | (vii) | (vii) | (vii) | (vii) | (vii) | (vii) | 412.7 kWh |

© 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Shigenobu, R.; Noorzad, A.S.; Muarapaz, C.; Yona, A.; Senjyu, T. Optimal Operation and Management of Smart Grid System with LPC and BESS in Fault Conditions. *Sustainability* **2016**, *8*, 1282.
https://doi.org/10.3390/su8121282

**AMA Style**

Shigenobu R, Noorzad AS, Muarapaz C, Yona A, Senjyu T. Optimal Operation and Management of Smart Grid System with LPC and BESS in Fault Conditions. *Sustainability*. 2016; 8(12):1282.
https://doi.org/10.3390/su8121282

**Chicago/Turabian Style**

Shigenobu, Ryuto, Ahmad Samim Noorzad, Cirio Muarapaz, Atsushi Yona, and Tomonobu Senjyu. 2016. "Optimal Operation and Management of Smart Grid System with LPC and BESS in Fault Conditions" *Sustainability* 8, no. 12: 1282.
https://doi.org/10.3390/su8121282