当发电机回路发生单相接地，电流大于规定值时，有可能产生弧光接地过电压，而发电机耐压水平较弱，绝缘容易损坏。如果接地电流过大，还会造成发电机铁芯灼伤及烧结。
When the single-phase grounding occurs in the generator circuit and the current is greater than the prescribed value, the arc grounding overvoltage may occur, while the voltage withstanding level of the generator is weak and the insulation is easily damaged. If the grounding current is too large, it will cause burns and sintering of the generator core.
通常在发电机中性点采用高电阻接地方式，以限制弧光接地过电压，减少对铁芯的灼伤，同时可提高继电保护的灵敏度，作用于跳闸使过电压限制在相电压的2.6倍以内，限制电弧的重燃，防止弧光间隙过电压损坏主设备，同时抑制铁磁谐振过电压，从而保证发电机的运行安全。
In order to limit arc grounding overvoltage and reduce burning to iron core, high resistance grounding method is usually adopted at neutral point of generator. At the same time, the sensitivity of relay protection can be improved. The overvoltage can be limited to 2.6 times of phase voltage by tripping, the reburning of arc can be restricted, and the main equipment can be prevented from being damaged by arc gap overvoltage. Suppression of ferroresonance overvoltage ensures the safety of generator operation.