基于双端直流注入切换采样原理的发电机转子接地保护

为提高发电机转子接地保护的可靠性，降低保护装置成本，提出了一种基于双端直流注入切换采样原理的改进转子接地保护方案。该方案在计算转子接地电阻时取消了转子电压保持不变的假定条件。利用转子直流漏电流等电气量信息进行转子接地保护回路异常的判别，并针对转子回路过电压问题给出了几种工程解决方案。试验结果表明，基于双端直流注入切换采样原理的改进转子接地保护可靠性高、动态测量性能好。

Earth Fault Protection for Generator Rotor Based on Switching Sampling Principle with Double-end DC Injection

In order to improve the reliability of earth fault protection for the generator rotor and reduce the cost of the protection device, an improved rotor earth fault protection scheme based on the switching sampling principle with double-end DC injection is proposed. In this scheme, the assumption that the rotor voltage remains unchanged is cancelled when the rotor earth resistance is calculated. The DC leakage current of the rotor and other electrical information are used to identify the abnormality of circuit for earth fault protection for the generator rotor. Several engineering solutions are proposed for overvoltage problem of the rotor circuit. The test results show that the improved earth fault protection based on switching sampling principle with the double-end DC injection has high reliability and good dynamic measurement performance.