Through analyzing the two cases of protection malfunction due to incorrect connection of open - delta connection of busbar voltage transformer , the importance of correct connection of open - delta connection when earthing fault occurring in a power system was explained 摘要通過(guò)分析兩起母線電壓互感器開(kāi)口三角形接線錯(cuò)誤引起的保護(hù)不正確動(dòng)作,從而說(shuō)明在系統(tǒng)發(fā)生接地故障時(shí)電壓互感器開(kāi)口三角形接線正確的重要性。