扩大单元接线发电机组定子接地保护的选择性研究  

Research on the Selectivity of Stator-ground Fault Protection for Generators in Expanded Unit Connection

作　　者：贾文超 黄少锋[1] 

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),河北省保定市071003

出　　处：《中国电机工程学报》2014年第28期4941-4949,共9页Proceedings of the CSEE

摘　　要：为了解决目前扩大单元接线发电机组定子接地保护无选择性的问题,提出了利用导纳不对称度与接地测量电阻作为选择元件的100%选择性定子接地保护方案。导纳不对称度参数综合考虑了工频零序分量信号和注入信号,可表征发电机对地导纳的三相不对称程度。理论分析、仿真及测试结果表明:故障发电机的导纳不对称度远大于非故障机组。应用该方法可实现:发电机区内故障时保护可靠动作,区外故障时保护可靠不动作;且该方法在各种中性点接地方式下保护均具有较高的灵敏性。该方案灵敏度高,性能稳定,能满足高阻接地故障时保护的要求,仿真和测试结果验证了该方案的可行性。At present the stator ground fault protection has no selectivity when it is used for generators in expanded unit connection, to solve this problem, a new 100% stator ground fault protection which uses the admittance asymmetry parameter and grounding resistance as the select element was proposed. Admittance asymmetry parameter, considering the zero-sequence component with power frequency and the injected signal, can describe the asymmetry degree of the three phase-ground admittances. The theoretical analysis, simulation and test results show that： the admittance asymmetry of faulty generator is much larger than that of non-faulty generators. The protection can operate reliably for internal faults, and be blocked for external fault by using this method; and it is sensitive for all neutral grounding modes. The protection scheme is very sensitive and stable, and can be used to detect high impedance grounding fault, simulation and test results show that it is feasible.

关 键 词：电力系统 发电机 扩大单元接线 定子接地保护 导纳不对称 注入信号 

分 类 号：TM77[电气工程—电力系统及自动化]