直接并网的中小型发电机定子接地保护

Stator Ground Fault Protection of Direct Generator-Bus Connection

指出了现有中小型发电机定子接地保护原理的不足。详细阐述了在发电机中性点不接地和经消弧线圈接地2种情况下,分别在系统侧单相接地和定子接地时机端零序电流和零序电压的方向关系。提出了基于零序电流与零序电压方向关系以及基于零序差流与零序电压方向关系的新型的定子接地保护原理。通过试验和现场运行情况表明了该保护原理的可行性。

The drawbacks of present stator ground fault protection principle for the small and medium sized generators are pointed out. Then the characteristics of direction relation between zero sequence current and zero sequence voltage are discussed when system single-phase ground fault or stator ground fault occurs under the circumstances of neutral ground via Petersen coil or neutral non-ground. A new stator ground protection principle is proposed based on the direction relation between zero sequence current and zero sequence voltage as well as the direction relation between zero-sequence differential current and zero sequence voltage. Tests and field operation demonstrate the feasibility of the principle proposed.