Photovoltaic Power Generation Modeling And Impact Analysis For Distribution Network Protection

With shortages of energy and electricity restructuring, the power supply that the large grids are combined with the distributed generation is considered as the main method to improve system security, reliability and flexibility. Because of the capacity constraints, the distributed generation is generally access of radiant network. It makes the distribution network with a single power supply into a more complex network, which changes the power flow, which changes the value, direction and distribution of the short circuit when the short circuit faults happen. It will have a negative impact to original protection and automatic devices of the original system. With variation of the type, capacity and position of distributed power, the impact will be greatly different. Using the data from PV in Binhai New Area, Tianjin, this paper establishes the accurate PV model and analyses on the line and automatic devices when the distributed generation is access to the different positions of the network.In aspects of PV model structures: based on the study of voltage and current relationship, the paper applies a method approaching to solve the key issues of photovoltaic energy conversion - maximum power tracking control. The method combines the particle swarm optimization with BP neural network. In the part of photovoltaic inverter control, the PQ control strategy is applied to achieve the transformation of DC and AC. Finally, the paper establishes the model of photovoltaic and network which the PV has been access to with the simulation software-DIGSILENT.The impact on protection: According to the relative relation of the feeder and photovoltaic power, the paper quantitatively analysis the power assisted and diffluence of distributed power, calculates the changes of sensitivity in current protection of different lines, studies the error activities and other issues which the feeder protection of distribution network may occur.The impact on automatic devices: According to the different location of photovoltaic power generation, The paper analysis the failure determination and fault location of FTU automatic. the paper also analysis the photovoltaic power generation impact on the recloser in the theoretical.