Voltage Regulation of Distribution Feeders by Distributed Energy Resources Coordination Control in Microgrid

Driven by the rising awareness of environment protection and energy policies, distributed energy resource (DER) has become one of the important technologies for future power system applications. When a large of photovoltaic (PV) is integrated into the power system, the problem of voltage fluctuation that affects the safety and stability on system operations may be met. It is thus necessary to seek useful manners for the mitigation and improvement of this problem. In this paper, a AC microgrid system operates in a 11.4 kV distribution feeder is studied. A coordination control strategy based on the implementations of on-load tap changer (OLTC) transformer and PV inverter (PVI) in microgrid will be proposed for the voltage regulation of the studied distribution feeder. In proposed method, local voltage level (LVL) method and voltage/var control (VVC) method will be separately used for OLTC transformer and PV inverter, and MATLAB/Simulink will be used to carry out the proposed method and to perform simulation test. Finally, simulations under un-coordination and coordination controls will be compared to verify the proposed voltage regulation method.