基于负序电流的主动配电网单相断线故障保护方法

随着分布式电源(DG)的接入以及主动配电网(ADN)的迅速发展,网络结构日趋复杂,断线故障频发,严重威胁设备与人身安全,影响电力系统稳定运行。由于受DG和可变拓扑的影响,ADN断线故障的识别面临较大的挑战,现有研究存在一定的空白,因此提出了一种基于负序电流的ADN单相断线故障保护方法。首先解析分析了DG上、下游发生单相断线故障时故障馈线与非故障馈线序电流以及ADN中性点电压的变化特征。在此基础上,以中性点电压和负序电流作为保护特征量构造了保护判据,提出了中性点经小电阻接地的ADN断线故障保护方法。理论分析和仿真结果表明,该保护方法不受负荷分布、故障位置、网络拓扑的影响,具有灵敏度和可靠性高、适用范围广以及易于实现的优点。

Single-phase break fault protection method for an active distribution network based on negative sequence current

With the access of Distributed Generation (DG) and the rapid development of the Active Distribution Network (ADN), network structure is becoming increasingly complex, frequent break faults seriously threaten equipment and personal safety and affect the stable operation of a power system. Because of the influence of DG, ADN break fault identification faces greater challenges, and there is still a gap in existing research. This paper proposes a single-phase break fault protection method for ADN based on negative sequence current. First, the characteristics of sequence currents and neutral voltage in the case of a single-phase break fault occurring in the upstream and downstream of DG are analyzed. The neutral voltage and negative sequence current are used as the protection parameters, and a single-phase break fault protection criterion for ADN with small resistance grounding based on negative sequence current is constructed. Theoretical analysis and simulation results show that the method is not affected by load distribution, fault location and network topology. It has high sensitivity, reliability, applicability and ease of implementation. This work is supported by the Joint Fund of National Natural Science Foundation of China (No. U1866603).