配电线路无通道保护能在不依赖通讯的前提下快速、有选择性切除不对称故障,以此为核心的配电线路自动化系统在发生对称故障时却性能不佳。该文提出一种在对称故障时快速切除故障、闭锁备用电源投入的方案:靠近电源的配电线路无通道保护在对称故障时瞬时动作切除故障,避免电气设备过热损坏;备用电源自动投入装置检测电压跌落时两周期前的负序电压大小,避免环网开关在对称故障时合闸到永久性故障后再次跳闸。EMTP(electro-magnetic transient program)仿真验证了该方案的有效性。
Distribution line non-communication protection (DNCP) can quickly and selectively isolate unsymmetrical faults, but the performance of the distribution line automation system is not satisfactory with symmetrical faults. This paper presents a scheme which can quickly isolate symmetrical faults and block the operation of the reserve power source automatic connection device (BZT). The DNCP which is closed to the source operates instantaneously to avoid overheating of the electrical equipment. When the voltage magnitude falls, the BZT will detect the negative voltage two cycles earlier to make a decision to avoid connecting to a permanent fault and tripping again for the ring main unit. Electro magnetic transient program (EMTP) simulations show the effectiveness of the scheme.