适用于花瓣形配电网的联络线后备保护方案

Backup Protection for Tie Lines in a Petal Distribution Network

花瓣形配电网具有高可靠供电的特点,其拓扑结构比传统的配电网更加复杂。针对联络线后备保护在变电站附近故障时隔离时间较长的问题,提出了一种新的后备保护方案。首先利用多端差动保护的思想判别出故障联络线所在的花瓣环,再根据各段联络线有功功率的变化趋势判断故障联络线,从而触发断路器跳闸隔离故障,并研究了主保护与后备保护的配合问题,最后利用PSCAD/EMTDC建立花瓣形配电网保护模型,分析了所提方案的保护动作和故障隔离情况,验证了保护的效果。结果表明,与传统的后备保护相比,此方案能够缩短变电站附近故障的隔离时间,且不受电网负荷和故障位置的影响,减少了电网中的采集设备数量。

The petal-shaped distribution network has the characteristics of higher reliable power supply,but its topology is more complex than the traditional distribution network.A new backup protection scheme is proposed to solve the problem that the isolation time of the backup protection of the tie line is long when the fault occurs near the substation.Firstly,the idea of multi-terminal differential protection is used to identify the petal ring where the fault tie line is located,and then the fault tie line is judged according to the variation trend of the active power of each section of the tie line,so as to trigger the trip of the circuit breaker and isolate the fault,and the logiccoordination of the main protection and backup protection is studied.Finally,PSCAD/EMTDC is used to establish theprotection model of the petal distribution networkto explore the protection action and fault isolation of the proposed method and the effectiveness of it.The results show that,compared with other backup protection methods,this method can greatly shorten the time to isolate the fault and it is not affected by loads and fault location.It can also reduce the measurement equipment in the system,which has higher popularization value.