主保护消除死区的方法探讨

旁路开关代主变开关运行时，常用的做法是将变压器的差动电流回路被切换到主变的套管电流互感器二次电流回路，这样就形成了一段无主保护的死区，该文提出了两种解决方案一是将旁路电流互感器再启用一备用绕组切换到主变差动保护电流回路。将死区纳人差动的保护范围；二是采用将旁路保护的距离保护投人跳闸位置，而高频保护、零序保护、综合重合闸等退出，一旦发生死区内故障，保护出口跳旁路开关，并比较了它们的优缺点。

Method Discussion of Main Protection Eliminating Dead Zone

It is common method to switch differential current circuit of transformer to secondary current circurt of bushing type current transformer when by-pass switch instead main transformer switch,That formed a dead zone without main protection. This paper proposes that by-pass current transformer switch a standby winding again to main transformer differential protection current circuit, makes dead zone into the range of differential protection and switch distance protection of by-pass protection to tripping position, but high-frequency protection,zero-sequence protection removed,Once happening fault in dead zone,there are two resolve method about protection exit trip by-pass switch,and compares their shortcoming and advantage.