架空-电缆混合线路的自适应保护方案

介绍配电网输电线故障时,根据输电线路始端所测得的电流的变化情况而提出的一种自适应保护方案.该方案利用一个附加的电流继电器来记忆故障前的负荷电流,分析故障后的电流变化情况,以判别故障发生的地点.该方案用于架空-电缆混合线路,使得架空线的距离Ⅱ段具有较高的灵敏度,不仅能以较短的时限切除本线路的故障,同时,又能作为电缆线路的后备保护,并能判别故障发生的区域,对断路器的动作做出自适应的调整,既能以较短的动作时限切除故障,又能保证保护的选择性.

Self-adaptive protection plan for overhead-cable mixed lines

Based on the current changes measured at the initial points of transmission lines when faults occur, a self-adaptive protection plan is put forward. The plan uses an additional current relay to recall the load current before faults, and analyzes the after-fault current changes to locate the faults. By applying the plan to the overhead-cable mixed lines, the II distance protection of the overhead lines will possess so high sensitivity that it can not only cut off faults of the lines within a short time period, but also act as the backup protection for cable lines to locate the faults, make self-adaption on the action of the circuit breakers. In general, the plan can be used to cut off faults within a short action time while guaranteeing the selectivity of protections.