电刷接触不良对发电机旋转励磁回路接地保护性能的影响  

Impacts of Brush's Bad Contact on the Performance of Grounding Protection of Generator Rotating Excitation Loop

作　　者：郑茂然[1] 陈建玉[1] 吴崇昊[1] 

机构地区：[1]国电南瑞科技股份有限公司,江苏省南京市210003

出　　处：《电力系统自动化》2007年第20期94-97,共4页Automation of Electric Power Systems

摘　　要：针对电刷与滑环间接触不良会对旋转励磁式发电机励磁回路接地电阻的正确测量产生影响的问题,提出了励磁回路接地保护的统一模型。利用该统一模型,分析了外加直流电压法、外加交流电压法、乒乓切换法中电刷接触电阻对励磁绕组接地电阻测量值的影响和危害。得出如下结论:对于外加直流电压法,电刷接触不良使接地电阻的测量值增大,可能导致继电器拒动;对于外加交流电压法,电刷接触不良使接地电阻测量值或减少或增大,可能导致继电器误动或拒动;对于乒乓切换法,电刷接触不良对保护性能的影响与接地位置有关。Because the brush＇s bad contact has some impacts on the correct measurement for the excitation loop grounding resistance of the rotating excitation generator,this paper sets up a uniform model to the excitation loop grounding protection.Based on this model,this paper analyzes the impacts of the brush touching resistance on the measurement of the grounding resistance when the impressed DC voltage method,the impressed AC voltage method and the Ping-Pang switch method are adopted respectively,obtaining the following conclusions：for the impressed DC voltage method,the measurement value of the grounding resistance will ascend,which may cause relay failure to operate;for the impressed AC voltage method,the measurement value of the grounding resistance will firstly descend,and then ascend,which may cause relay misoperation firstly,and then failure to operate;for the Ping-Pang switch method,the measurement value of grounding resistance is related to the grounding position and is uncertain.

关 键 词：旋转励磁发电机 电刷接触电阻 励磁回路接地保护 外加直流电压法 外加交流电压法 乒乓切换法 

分 类 号：TM31[电气工程—电机] TM862