基于电流微分状态量的直流配电网分布式区域保护

Distributed Area Protection for DC Distribution Network Based on Current Differential State Variable

针对现有直流配电网单端量保护选择性差、多端量保护速动性差、数据同步要求高等问题,提出一种基于电流微分状态量的直流配电网分布式区域保护方法。该方法以负荷分支公共接入点为分界对直流线路进行区域划分,利用电流微分作为故障暂态特征量,相邻保护装置交换电流微分状态字的信息进行故障类型判定与区域定位,实现故障的快速定位与隔离。该方法只需要相邻保护装置交互故障电流微分状态信息,不需要严格的数据同步,可用于双端或多端直流配电网。仿真结果表明,所提保护方法具有较好的速动性与选择性,且具备一定的耐受线路分布电容和过渡电阻能力。

Aiming at the problems of poor selectivity of single-end protection,as well as slow operation speed and strict data synchronization requirements of multi-end protection in the existing DC distribution network,this paper proposes a distributed regional protection method for DC distribution network based on current differential state variable.This method uses the load branch common access point as the boundary to divide the DC lines and uses the current differential as the fault transient characteristics.Adjacent protection devices exchange current differential status words for fault identification and area location,to achieve rapid fault location and isolation.The method only needs the exchange of fault current differential status information between adjacent protection devices.And the strict data synchronization is not required.It can be used for two-end or multi-end DC distribution networks.Simulation results show that the proposed method has fast operation speed and accurate selectivity,and has a certain ability to withstand the distributed capacitance of line and transition resistance.