Discussion on setting scheme of collecting line relay protection in wind farm based on a DFIG short-circuit characteristic

At present, a wind farm is often used as a load or conventional power source for analysis and calculation in a fixed value setting. This has led to a number of accidents. Therefore, it is very important to study in detail the fault characteristics of the wind farm and its impact on system relay protection. First, on the basis of a DFIG short-circuit equivalent parameter model, this paper studies the turbine generator short circuit characteristics of collecting line protection and the collecting line relay protection setting method. Then, it takes the influence of the turbine generator short circuit fault current into account, and puts forward a set of complete relay protection setting methods for the collecting line system. This method analyzes the three-phase short-circuit current and two-phase short-circuit current, and presents the setting principle and calculation process of collecting line inter-phase overcurrent protection and zero-sequence current protection of a collecting line ground fault. This strategy avoids the impact and mis-operation of the relay protection device of the downstream collecting line caused by the overcurrent of a turbine generator fault. It has been applied in a real wind power plant, verifying the effectiveness of the method. © 2020, Power System Protection and Control Press. All right reserved.