Eiji Kamiya

Voltage regulation in distribution system utilizing electric vehicles and communication

Challenges for the low carbon society has brought a spread of electric vehicles (EVs). Most of EVs could be charged at night simultaneously. That could cause severe voltage drop along the feeder. On the other hand, EVs are able to inject/absorb reactive power by using interfacing inverter in principle. This paper proposes active and reactive power management which can regulate feeder voltages in the distribution system avoiding short in charged energy. This paper also proposes a communication scheme among EVs and distribution system operators to realize more effective voltage regulation in the distribution system.

Centralized voltage control method of load ratio control transformer and step voltage regulator for bank fault restoration

This paper presents and verifies a method for centralized voltage control of load ratio control transformers and step voltage regulators for bank fault restoration. In conventional methods, voltage control in distribution systems primarily serves to alleviate voltage violations. Conventional methods remain imperfect, however, so it is necessary to evaluate how to minimize the number of violations during bank fault restoration. Thus, the proposed method adjusts the tap position of voltage regulators to minimize the number of affected customers in consideration of the power factor control of photovoltaic generation systems. We perform numerical simulations of bank fault restoration to verify the effectiveness of the proposed method, and visually compare the results with those of the conventional method.

Study on Voltage Regulation in a Distribution System Using Electric Vehicles - Optimal Real and Reactive Power Dispatch by Centralized Control -

A surge of needs for the low carbon society promotes a spread of electric vehicle (EV). EVs could be charged at night simultaneously. That could cause severe voltage drop. Typical charger for EV employs the self-commutated inverter, which can control both active and reactive powers in principle. The authors have investigated potential availability of EVs for the distribution system operation qualitatively, and have concluded that the utilization of reactive power from EV charger could provide great potential for voltage regulation in the distribution system without loss of EV owners convenience. The authors have proposed some voltage regulation algorithms using EVs. This paper proposes a new algorithm - a centralized control method in which the distribution system operator collects information of each EV in the distribution system and controls them.

Development of three-phase to single-phase matrix converter for improvement of three-phase voltage unbalance in distribution system

In this paper, a distribution transformer using three-phase to single-phase matrix converter with an AC inductor is proposed to suppress three-phase voltage unbalance. The AC inductor is used for compensation of single-phase power pulsation at any load conditions. Control strategy and simulation results are shown in this paper. The effect of proposed method is confirmed by the simulation with MATLAB/SIMULINK.

Validation of voltage regulation method in distribution system utilizing electric vehicles

A surge of needs for the low carbon society promotes a spread of electric vehicle (EV). EVs could be charged at night simultaneously, as a result, severe voltage drop may happen. Typical charger for EV employs the self-commutated inverter, which can control both active and reactive powers in principle. The authors are investigating the availability of EVs for the distribution system operation qualitatively, and have proposed voltage regulation algorithms using EVs. This paper validates the performance of proposed algorithms from the practical points of view based on the Monte Carlo simulation.

Method of Optimal Allocation of SVR in Distribution Feeders with Renewable Energy Sources

Abstract – In this paper, the authors propose a determination method of optimal allocation and transfer of step voltage regulators (SVRs) in distribution feeders with renewable energy sources (RES). The feature of the proposed method is to determine optimal allocation and transfer of SVRs based on the forecasted amount of PV introduced to distribution feeders a few years later and cooperative controlling of SVRs and LRT. In the proposed method, voltage margin is maximized under a constraint that all the node voltages are controlled within the proper range for a certain period of years. In order to verify the validity of the proposed method, the optimal allocation and transfer of SVRs obtained by the proposed method is compared with the optimal one of the conventional approach. In the numerical simulation results, the number of transfer and install of SVR with the proposed method is reduced from those of conventional method. Keywords : Optimal allocation, SVR, Distribution system, Voltage control, Renewable Energy Sources