对称电压跌落条件下双馈风电机群馈出电流与线路电流保护的交互影响  

Study for Reciprocal Effect Between Overcurrent Protection and Doubly-fed Induction Generator Feeding Current Under the Condition of Symmetrical Voltage Sag

作　　者：童宁[1] 林湘宁[1] 李正天[1] 张锐[1] 

机构地区：[1]强电磁工程与新技术国家重点实验室(华中科技大学),湖北省武汉市430074

出　　处：《中国电机工程学报》2014年第22期3806-3814,共9页Proceedings of the CSEE

基　　金：国家重点基础研究发展计划项目(973项目)(2012CB215100);国家自然科学基金项目(51207064)~~

摘　　要：随着风电机组低电压穿越能力的加强和风电场规模的扩大,风机提供的短路电流变得不可忽视,对现有的风电场保护配置形成了挑战。首先介绍了大量含有双馈异步风电机组的酒泉风电场结构及保护配置,理论推导并仿真研究了单一风机对称电压跌落条件下定子电流的时频域特征,进而针对保护能够感受到的工频交流分量,研究不同风机侧及网侧参数条件下的风电集群馈出电流与集电线路电流保护的交互影响,并指出保护可能存在的误动风险。研究结果表明,中压集电线路故障可能引发邻近线路电流保护的误动,而合理的Crowbar电阻阻值及风电场资源配置可降低其误动风险。加装方向元件可在上述参数无法形成有效配合时避免电流保护误动,从而能够增强风电场的故障穿越能力。With the enhancement of LVRT capacity of wind generators and the enlarging scale of wind farms, feeding currents of wind generators can no longer be ignored in many cases. This scenario may result in challenge to existing protection configuration in wind farms. In this paper, the structure of Jiuquan wind farm and protection arrangement was introduced. For a single generator, the characteristics of stator currents in time-frequency domain for symmetry voltage sags were analyzed and simulated. The power frequency components of currents detected by relay protections were analyzed to study the interaction between the feeding currents of wind farm cluster and over-current protection under different lengths of feeder and crowbar resistances, and it was pointed out that the protections may maloperate. Research results show that the faults in medium voltage feeder cable may result in maloperation of over-current protections of adjacent feeders. Reasonable Crowbar resistances and allocation of wind farm can reduce the maloperation risk of protections. If above countermeasures are not available and the possibility of mal-operation of over-current protection exists, directional element must be configured for the existing protection.

关 键 词：双馈异步风机 短路电流 时频域分析 电流保护 

分 类 号：TM614[电气工程—电力系统及自动化] TM773