浅谈小浪底水电厂发电机定子单相接地保护

Discussions on the protection of single phase earthing of the generator's stator in Xiaolangdi Hydropower Plant

定子绕组的单相接地是发电机最常见的故障之一,为此,小浪底水力发电厂发电机定子单相接地保护采用了双频式保护,即用基波零序电压原理保护距机端约80%的定子绕组,而用3次谐波电压原理保护中性点附近的定子绕组。但经实践后证明,这种定子接地保护配置还不很完善,难以满足可靠性和灵敏性的要求,相信随着运行经验的积累和科学技术的发展,水力发电厂的定子接地保护会日臻完善。

The faults of single phase earthing of stator winding is one of the most frequent faults. For this reason, double-frequency protection is adopted in the single phase earthing protection, that is, it used the base-wave zero sequence voltage principle is used to protect approximately 80% winding of the stator and the 3-time harmonic wave voltage principle to protect the stator's winding section around the generator's neutral point. According to practical operation experience, such kind of configuration of the protection of single phase earthing is not perfect, it can't meet the requirements of the reliability and sensitivity .It is convinced that the protection of single phase earthing protection of generator's stator will be improved greatly with the accumulation of operation experience and the development of technology.