提升配电网线路保护可靠性的远方保护及其与就地保护优化配合方案研究

Research on Remote Protection and the Optimized Coordination Scheme of Local-Remote Protection to Enhance the Protection Reliability of the Line in Distribution Network

在配电网中,线路保护一般仅采用单套配置的电流三段式保护,因此存在可靠性低、易受采样环节影响等问题。另外,大量分布式电源(DG)的接入,使得其中的瞬时速动过电流Ⅰ段保护范围显著缩小。为解决以上问题,该文充分利用线路及其所连接的母线背侧电流信息,构造多重化纵联保护判据,并提出具备抗采样异常能力的高可靠远方保护冗余跳闸逻辑,其中,保护判据利用超快速纵联保护算法来缩短判据计算时间,为信息上传、下达及处理环节留有足够的时间裕度,以实现远方保护与就地保护的有效配合。另外,充分考虑通信延时以及端子误碰或网络攻击带来的影响,提出基于智能断路器的保护跳闸逻辑,并在此基础上设计就地保护与远方保护最优配合方案。理论分析及仿真算例验证了该方案能有效地应对单个互感器出现干扰、饱和、断线等采样环节异常以及网络攻击的极端场景,提升了配电网保护的可靠性。

In the distribution network,the overcurrent protection is often single-configured for line protection,which has low reliability and is vulnerable to the sampling link.In addition,as many distributed generations(DGs)are connected to the distribution network,the protection range of instantaneous overcurrent protection is significantly reduced.Therefore,based on the current information of the line and the back side of the connected busbar,this paper proposes a highly reliable remote protection redundancy tripping logic with anti-sampling anomaly capability by constructing multiple differential protection criteria.The protection criteria use a superfast pilot protection algorithm to shorten the calculation time,which can provide sufficient time for information uploading,sending and processing,so as to realize the effective coordination of remote protection and local protection.In addition,considering the communication delay and the influence of accidentally collision of terminals or cyber-attack,the protection tripping logic based on smart circuit breaker is proposed,and the optimal coordination strategy of local protection and remote protection is designed.The theoretical analysis and simulation results verify that the proposed strategy can effectively deal with the abnormities of sampling,such as interference,saturation and disconnection of single transformer and cyber-attack,while improving the protection reliability of distribution network.