程真何,刘桂林.110kV线路零序电流保护误动原因分析及对策[J].电测与仪表,2014,51(23):. CHENG Zhen-he,LIU Gui-lin.Cause analysis on zero sequence current protection maloperation of the 110kV line and its countermeasures[J].Electrical Measurement & Instrumentation,2014,51(23):.
110kV线路零序电流保护误动原因分析及对策
Cause analysis on zero sequence current protection maloperation of the 110kV line and its countermeasures
In Xuzhou power grid,a single-phase outlet grounding fault happened on the 110kV line of a 220kV substation.It led to zero sequence currentSprotection maloperation of several 110kV lines. When the single-phase grounding fault happened,the zero sequence voltage appeared. It resulted in the neutral gap’s breakdown of 110kV transformers which were connected to the non fault line. Consequently, zero sequence current in opposite direction flowed in theSnon fault line.That is the reason of zero sequence current protection maloperation. In order to preventing the occurrence of similar accidents, the article put forward two countermeasures.That is to add a directional element,or only to use the last segment for the zero sequence current protection of the 110kV line.
