Coordinated Reactive Power Margin Management of Multiple Photovoltaic Inverters for Voltage Regulation in Distribution Networks

With the increase of photovoltaic (PV) penetration, the power beyond the demand may cause the voltage violation problem in distribution networks. On the other hand, due to the regulation ability of reactive power to voltage, this problem can be solved based on PV residual capacity. However, as long as one single PV inverter reaches the upper limit of power capacity, although other PV inverters have reactive power margin, the grid will still have the problem of voltage violation. Therefore, a reactive power margin management method of multiple PV inverters is proposed to comprehensively improve the effect of voltage regulation. Firstly, a high PV penetration distribution network model is built to analyze the relationship between PV reactive power margin and power flow. Then, the local PV control method and the reactive power margin optimization method are combined to realize voltage regulation. Finally, a five-bus distribution network is built in simulation and the results verify the rationality of reactive power margin management and the effectiveness of voltage regulation.