Application Of Adaptive Distance Protection In Distributed Network With Distributed Power

In recent years,China’s energy and environmental problems have become increasingly prominent-traditional energy sources have limited reserves and serious pollution.At the same time,the traditional power supplied modes(large units,large power grids,and high voltages)also show various problems as the grid becomes increasingly complex.In order to solve these problems,people began to turn their attention to the new energy field.At this time,as a supplement to the large-scale power grid,distributed generation(DG)has received great attention due to its flexibility,environmental protection,and economy,and has been rapidly developed.Fist,we introduced the DG that is currently widely used and introduced the development of wind power in Daqing.This paper makes a detailed analysis of the working principle and response characteristics of the above-mentioned inverter DG,and determines the model of the inverter distributed power and its control method,and decides to adopt PQ of constant power controlled mode to output stable active and reactive power.this paper analyzes the influence of DG access distribution network protection based on the Daqing oilfield distribution network.The analysis shows that the DG accessing will have a greater impact on the upstream and downstream sides: It will reduce the sensitive sensitivity of the current protection of the upstream protection,reduce the protection scope,and may refusal to move;it will increase the sensitivity of the current protection of the downstream protection,and the protection scope extending to the next line,so that lossing of coordination between protections may result in misoperationThen,this paper applies the longitudinal phase differential protection to Daqing distribution network and solves the problem of refusal and misoperation through sensitive all-line pilot protection.At the same time,the phase sequence component was introduced to solve the problem of dead-zone short circuit near the DG access point.Considering the complexity of multiple distributed power accesses,it was decided to combine adaptive distance protection for economic reasons.The adaptive distance protection used introduces quasi-quadrilateral characteristics and performs detailed analysis in the impedance complex plane.The combination of the two guarantees the economics of the operation and guarantees important aspects,such as the safety of large-capacity transformers.The parameters of Daqing distribution network were simulated by simulation software PSCAD to verify the effectiveness of the above method.Finally,for the actual project---photovoltaic grid in an industrial park and Daqing oil field distribution network.Photovoltaic chose six photovoltaic grid-connected companies in an industrial park in Shanghai,and made further improvements in the protection configuration in terms of their protection status.Through the simulation analysis of PSCAD software,the scheme was effective and effective;Wind power combined with Daqing oil field distribution network and Daqing Taiping wind farm,first analyze the impact of wind power may be to the traditional distribution network,and then focuses on the main protection configuration problems,and finally through the PSCAD software based on the actual distribution parameters for simulation verification,the results show that accurate effective.