风电场并网联络线的自适应电流保护研究

针对现有联络线源侧大多使用定值保护方案因而容易受风电特性影响而误动的现状,分析了风力发电机短路电流特性,得出了双馈型风力发电机的故障电流与电网故障发生时刻、故障类型、撬棒电路动作情况、故障后电压的跌落深度等密切相关的结论,并在此基础上提出了综合电流、电压信息的风电场联络线自适应速断保护原理与算法。该保护方法以某示范性分布式风电场并网进行DIgSILENT软件的仿真测试,结果验证了所提保护配置方案的自适应性和有效性。

Research on Adaptive Current Protection for Wind Farm Tie-Line

With an aim at the existing tie-line resource side with fixed value protection schemes,resulting in mal-operating situation because of being subject to the wind power characteristics,this paper analyzes the short circuit current behavior of the wind power generators,whereby such conclusions are obtained as defect types,crowbar circuit action,and fault-induced voltage sag level which are closely related to the occurrences of fault current of double-fed induction generator and the power grid fault,on the basis of which the new relay adaptive protection principle and algorithm for comprehensive electric current and voltage information for the tie-line in the wind farm are suggested.Finally,this protection scheme is tested on a certain exemplary distributed wind farm by the DIgSILENT simulation software.The test results show that the proposed protection scheme is adaptive and able to distinguish the internal or external faults effectively.