1999年 4月 2 8日发生在北京房山变电站的系统解列事故是华北电网历史上最为严重的事故之一。此次事故导致华北电网枢纽变电站——房山站 2 2 0 k V母线全停 ,进而使华北电网解列为3个独立系统 ,并造成部分负荷停电。文中简要介绍了事故的经过及处理过程 ,指出电网结构薄弱、电气主接线可靠性不高是这次事故扩大的主要因素。 April 28, 1999 occurred in Beijing Fangshan substation system unmanned accident is the history of North China Power Grid, one of the most serious accidents. The accident led to the bus station in North China Grid - Fangshan station 220V V bus full stop, so that the North China grid disaggregated into three separate systems, and cause part of the power outage. The paper briefly introduces the process of the accident, and points out the weakness of the power grid and the low reliability of the main electrical connection are the main factors of the accident.