Distributed Photovoltaic Power Generation Impactonrelay Protection

In the rapid economic developmental today's society,people will pay their attention to the photovoltaic power generation which is the representative of the new energy industry in order to meet growing energy needs and reduce environmental pollution of nature.But a growing number of distributed photovoltaic power generation bring extreme pressure to the original grid operation.This article aims to analyze the impact of distributed photovoltaic power generation on relay protection.First,this paper describes the background of this research and the status of each country and distributed photovoltaic power generation and some of the current industry technical standards. For green energy, many countries are seeking to develop distributed photovoltaic power generation.Secend,the article describes the types of photovoltaic power generation,and leads to the type of distributed photovoltaic power generation from the principle of photovoltaic power generation. Distributed photovoltaic power generation will bring some negative impact on the existing power grid, in order to ensure the safe operation of power grids, the internal of PV systems will take some appropriate protective measures,for example,anti-discharge protection, reverse polarity protection and overvoltage protection on DC side.In analyzing the impact of the distributed photovoltaic which incorporates into power grid effects on the relay of the power distribution network, take common three-current protection, distance protection and reclosing protection for example,the paper detailed analysis the sequence of actions and the scope of the relay when a fault occurs in the existing distribution network.The effects of distributed photovoltaic power incorporates into the distribution network about the three-current protection, line distance protection and automatic reclosing are discussed.It will make the existing grid relay malfunction or refuse to move.Finally this paper discusses the impact on the anti-islanding detection of grid configuration when distributed photovoltaic power incorporates into the grid. Existing anti-islanding detection is divided into two types of passive detection and proactive detection. Passive detection doesn't need to add disturbance so it will not affect the quality of the current. Active detection requires adding a small perturbation,it has high precision and small blind. Generally, using passive detection and proactive detection in the same time to increase reliability and reduce blind spots.When distributed photovoltaic systems incorporate into grid, several inverters in parallel may enlarge blind spots and reduce the accuracy of detection.Then,the article analyses the detective effects of combined three different detection methods.To prove the situations about a single inverter and two inverters in parallel,I use MATLAB/SUMILINK software.