220 kV线路单相永久性故障引起变压器间隙保护动作分析

Analysis of Transformer Gap Protection Action Caused by Permanent Single-Phase Fault on 220 kV Lines

在110 kV和220 kV电网中,根据电网运行的需要,有些变压器中性点不接地运行。在此运行方式下,线路出现故障有可能造成变压器中性点间隙击穿。为了保证保护的选择性,需要通过保护的时间进行配合。本案例是一起220 kV线路单相永久故障,单相重合不成功,变压器间隙保护时间整定不正确造成中性点间隙保护误动。

In the 110 kV and 220 kV power grids,some transformer neutral points operate ungrounded based on operational requirements.Under this operational mode,line faults can potentially cause breakdowns on the transformer neutral point gaps.To ensure the selectivity of protection,it is necessary to coordinate protection timing.This case involves a permanent single-phase fault on a 220 kV line where the single-phase recloser was unsuccessful,and improper timing setting of transformer gap protection led to misoperation of neutral point gap protection.