主变压器中性点间隙击穿引起的跳闸故障分析

Trip Fault Analysis on Neutral Point Gap Breakdown of Main Transformer

针对一起线路单相故障引起主变压器中性点间隙击穿故障,分析故障发生时主变压器中性点暂态过电压和零序保护整定值,提出增大中性点间隙大小和调整保护动作时间的建议,使有效接地系统非全相运行时保护不动作,保护主变压器中性点绝缘免受雷击损坏。

Aiming at the primary-neutral point gap breakdown accident caused by single-phase fault of a line, we analyze the transient over-voltage and zero-sequence protection setting of the main transformer neutral point when the fault occurs, after that we propose to increase the neutral point gap size and suggest adjusting the protection action time, so that the protection of the active grounding system is not working when it is in non-full phase operation, and the insulation of the main transformer neutral point is protected from lightning damage.