交流励磁发电机转子绕组一点接地保护

交流励磁发电机（ACEG）转子采用对称三相交流电励磁，能够实现有功、无功和转速的独立调节，在改善超高压电力系统的稳定性及变速恒频发电等领域有着广泛的应用前景。转子绕组一点接地是交流励磁发电机常见的一种故障，提出了采用外加直流电源的方法来检测三相励磁的交流励磁发电机转子一点接地，并分析了外加电源对原有励磁系统的影响。由于采用外加直流电源，所以此方法检测结果不受发电机运行状态的影响，可以对转子一点接地进行100％的保护，且灵敏度与接地位置无关。

Rotor winding one point to ground fault protection for AC-excited generators

There is a broad prospect for Alternating Current Excitation Generator (ACEG) in improving the stabilities of extra-high voltage power system and in constant frequency generation with variable speed, by using the three-phase alternating current excitation and realizing independent regulation of active power, reactive power and rotate speed. Rotor one point to ground fault is a common kind of faults of ACEG. This paper uses 100% rotor earth fault protection with DC voltage injection and analyses the influence of DC voltage injection on AC-excited system. By adopting DC voltage injection, the result of this scheme is free of operation state of the generator. The scheme can protect the 100% coverage generator rotor one point earth fault and the sensitivity has no relationship with the fault location.