风力发电系统短路故障特征分析及对保护的影响

Analysis of characteristics of short circuit fault of wind power system and the impact on the protection

为了进一步掌握风力发电系统短路故障特征并分析其对继电保护的影响,建立了双馈和直驱风电系统电磁暂态模型。通过电磁暂态仿真研究了风电系统短路电流及系统正负序阻抗的特征,得出了风电系统提供短路电流能力较常规电源弱和风电系统正负序阻抗不一致且随时间波动的结论。研究了常用输电线路继电保护原理对风力发电系统的适应性,得出了输电线路距离保护和选相元件受风力发电系统故障特征影响较大,可能发生不正确动作的结论。利用现场录波数据验证了故障特征及保护适应行分析的正确性,相关结论对继电保护的配置具有一定的借鉴意义。

Simulation models of double-fed induction generator and permanent magnet direct driven wind generator are built based on PSCAD/EMTDC software. The fault characteristics of wind generation system are studied, and the performances of relays in power systems with wind farm integration are analyzed. It can be concluded that the fault currents fed by wind generation are limited comparing with conventional synchronous generators. And the positive and negative sequence impedance of wind farm is not equal which is different from conventional power transmission system. Some widely used protection principles are studied and it is found that the distance relay and fault phase selector will be influenced by wind farm integration. Finally, some field fault data from recorder are used to verify the studies and analysis. The results show that the study and analysis conducted will be useful for the protection system setting and operation in power system with wind farm integration.