双馈异步风力发电机(DFIG)作为分布式电源接入配电网,能将辐射状的单电源系统变为双电源系统,改变配电网的拓扑结构.当配电网发生短路故障时,配电网的短路电流会受到风力发电接入的影响.针对DFIG作为分布式电源接入配电网,配电网中不同点发生三相短路故障时短路电流受到风力机接入容量及接入点位置影响的问题,结合DFIG的控制策略进行理论推导和仿真分析.首先,从理论上推导含风力发电的配电网短路故障电流关系式,对风力机提供的短路电流进行分析.然后,引入模型预测控制,与经典的矢量控制进行对比分析得出不同控制策略对短路电流的影响,并在此基础上分析配电网在不同点发生三相短路故障时,短路电流随风力机接入容量及位置的变化情况,分析总结DFIG对配电网短路电流及电流保护的影响.

The doubly-fed induction generator (DFIG) is connected to the distribution network as a distributed power source, which turns a radial single power supply system into a dual power supply system and changes the topology of the distribution network. When a short-circuit fault occurs in the distribution network, the short-circuit current of the distribution network will be affected by the access to wind power. Aimed at the problem that the short-circuit current is affected by the access capacity of the wind turbine and the location of the access point when DFIG is connected to the distribution network by distributed power sources and a three-phase short-circuit fault occurs at different points in the distribution network, a theoretical derivation and a simulation analysis are conducted by combining the control strategy of DFIG. First, relational expression of short-circuit fault current of the distribution network including wind power is theoretically derived, and the short-circuit current provided by the wind turbine is analyzed. Then, model predictive control is introduced to be compared with classical vector control to analyze the impact of different control strategies on the short-circuit current. The changes in access capacity and location are analyzed when a three-phase short-circuit fault occurs at different points in the distribution network, and the impact of DFIG on the short-circuit current of the distribution network is summarized.