CAJ | 학술논문

徐州地区电网某220kV变电站一条110kV出线出口发生单相接地故障时导致多条110kV线路零序电流保护误动。故障线路单相接地时产生的零序电压造成该变电站其它非故障线路馈供的110 kV变压器中性点放电间隙击穿，从而使非故障线路中流过反方向的零序短路电流是零序电流保护误动的原因。本文提出了110 kV线路零序电流I、II保护增加方向元件，或者只使用零序电流末段保护的对策，并应用于徐州电网，取得了良好的运行效果。
서주지구전망모220kV변전참일조110kV출선출구발생단상접지고장시도치다조110kV선로령서전류보호오동。고장선로단상접지시산생적령서전압조성해변전참기타비고장선로궤공적110 kV변압기중성점방전간극격천，종이사비고장선로중류과반방향적령서단로전류시령서전류보호오동적원인。본문제출료110 kV선로령서전류I、II보호증가방향원건，혹자지사용령서전류말단보호적대책，병응용우서주전망，취득료량호적운행효과。
In Xuzhou power grid, a single-phase outlet grounding fault happened on the 110kV line of a 220kV sub-station, which led to zero sequence current protection maloperation of several 110kV lines.The zero sequence volt-age, which appeared when the single-phase grounding fault happened,resulted in the neutral gap’ s breakdown of the 110kV transformers which were connected to the non-fault lines.Consequently, the zero sequence short circuit cur-rent flowing in the opposite direction through the non-fault lines was responsible for the zero sequence current protec-tion maloperation.This paper put forward two countermeasures:one was to add a directional element to the zero se-quence current I, II protection of the 110kV line, and the other was only to use the last segment protection of the zero sequence current.The two countermeasures have been applied to Xuzhou power grid and good operation results have been achieved.