This paper analyzes detailedly the principles on distributed busbar protection - current instantaneous value differential method , impedance method , and put forward the new method of current fault component phase method , then compares with these methods 本文详细分析了分布式母线保护中的原理?瞬时值电流差动法、阻抗法，提出了电流故障分量相位法的新方法，将这几种方法进行比较。
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 摘要通过分析两起母线电压互感器开口三角形接线错误引起的保护不正确动作，从而说明在系统发生接地故障时电压互感器开口三角形接线正确的重要性。
