大型发电机注入式定子接地保护的现场应用及分析

Field Application and Analysis of the Stator Earth Fault Protection with Voltage Injection for Large-sized Generator

近年来越来越多的大型发电机装设100%注入式定子接地保护。文中总结了注入式定子接地保护现场调试方法,给出了试验结果。试验结果验证了保护装置检测接地过渡电阻的准确性(相对误差不超过±5%)。另外,通过分析电压回路两点接地故障引起的定子接地保护告警,给出了若干建议。

More and more large-sized generators are installed 100% stator earth fault protection with low-frequency alternating-voltage injection. The field adjustment methods of the voltage injection scheme against the stator earth fault protection are summarized and the experimental results are given. The equipment measuring accuracy （relative error is not greater than ±5%） of the earth fault resistors is verified by the experimental results. Moreover, some suggestions are given by analyzing a two-point earth fault in potential transformers circuit, which can cause stator earth fault protection warning.