高压开关柜电缆头故障保护升级应用

Application of Fault Protection of H-voltage Switch Cabinet

高压开关柜下口高压电缆头会因为绝缘损坏、制作工艺等问题发生闪络事故,闪络过程中由于电弧电阻的原因,短路电流达不到电流速断保护、过电流保护定值,且故障范围位于零序电流互感器上方,保护装置无零序电流采样,造成该故障无保护切除,使故障电弧持续快速发展直到产生无法逆转的严重后果,以致由发变组后备保护切除故障。基于此,本文对高压开关柜电缆头故障保护升级应用进行研究,期待减少电缆室内电缆头闪络事故的发生。

The high-voltage cable head at the lower mouth of the high-voltage switchgear will have a flashover accident due to insulation damage,manufacturing process and other problems,and the short-circuit current can not reach the current quick-break protection and overcurrent protection fixed value due to the arc resistance in the flashover process,and the fault range is located above the zero-sequence current transformer,and the protection device has no zero-sequence current sampling,resulting in the fault being cut off without protection,so that the fault arc continues to develop rapidly until it produces irreversible serious consequences,so that the fault is cut off by the backup protection of the transformer group.Based on this,this paper studies the application of fault protection upgrade of cable head in high-voltage switchgear,and expects to reduce the occurrence of cable head flashover accident in cable room.