The Influence And Countermeasure Of Wind Turbine Generator To Distribution Network On Relay Protection

As a new generation technology,distributed generation had been developed and applied in recent years because of its advantages of flexibility,environmental protection and economy.When the distributed generation was connected to the distribution network,the structure of the distribution network changed.The simple distribution network of the unidirectional power flow had become a complex distribution network.The protection device on the distribution network would be affected,which will brought the test to the safe operation of the distribution network.After the distributed generation was connected to the grid,the traditional current protection could not meet the requirements of the relay protection,so it was necessary to improve the inherent protection and find more effective methods.Based on the analysis of distributed power supply technology,a simulation model of 10kV distribution network with wind turbine was established.In this paper,the influence of wind turbine on the protection of distribution network is studied from the aspects of fan capacity,access location and fault location.Get conclusion:Located at the downstream of the fan,the wind can provide a large short-circuit current to the fault point,resulting in the downstream protection scope to expand and thus lose the selectivity.Located in the upper reaches of the fan protection,the wind to the fault point to provide a reverse short-circuit current,resulting in the loss of directional protection upstream.The analytical results are confirmed by MATLAB simulation.Considering that the traditional protection could not adapt to the change of the distributed power access to the distribution network,it had a great impact on the safe operation of the distribution network.This paper studies the application of adaptive current protection technology,putting forward a new method for solving the equivalent impedance.It was based on the data measured before and after the fault protection device,using the symmetrical component method to extract the positive sequence component to solve the problem.The performance of the adaptive current protection was better than that of the traditional protection,which could meet the requirements of the wind power unit in the distribution network,and it was reliable in the scope of protection.The feasibility of the algorithm was verified by MATLAB simulation.