备自投装置在单母分段接线中应用存在的问题及解决措施

The problem existing in automatic close-up device of stand-by power supply used in sectionalized single bus scheme and its solving measures

单母分段接线与内桥接线在运行方式上极为相似,但目前的备自投装置不能直接应用于终端变不配置母线保护的单母分段接线方式,存在母线故障无法闭锁备自投的问题。提出增加带反方向的线路保护作为母线故障时备自投的闭锁条件。同时,在进线备自投逻辑中,带反方向的线路保护无法选择性区分母线故障,造成任一段母线故障一律闭锁备自投,导致负荷全部丢失的后果。提出在进线备自投逻辑中增加判断母联是否流过故障电流的判据,而母联故障电流定值的整定可以采用母联过流方法,也可以采用更为灵敏的故障相电流突变量的方法。

The operation mode ofsectionalized single bus is similar to that of internal bridge scheme. However, the present close-up device of stand-by power supply can＇t be directly used in sectionalized single bus scheme without busbar protection at the terminal substation, because there is a problem that automatic device won＇t be blocked due to the faults of any bus. For this reason, line protection with the inverse direction is suggested to be added to the logic for automatic close-up device of stand-by power supply which will make automatic device be reliably blocked. At the same time, in the mode of power line stand-by power supply, it can＇t judge which bus is at fault for line protection with the inverse direction, and automatic device will be blocked due to the fault of any bus, which results in non-selective action of automatic device, and it will come to the ending that all loads are lost. To solve the problem, the paper suggests that it needs to add a criterion judging whether there is fault current going through the bus sectionalizing breaker to the action logic of power line stand-by power supply, and the setting of fault current can adopt the method of over-current, or more sensitive method of current variation of fault phase.