有源配电网分布式故障自愈方案与实现

大量分布式电源(DG)接入配电网,使传统的配电网保护与控制面临较大的困难。为解决有源配电网所面临的诸多问题,提出了一种基于智能终端单元(STU)的分布式故障自愈方案。该方案采用分相电流差动与故障电流幅值比较作为故障区段定位原理,能够适应于含有多种DG类型与不同DG渗透率的有源配电网。在负荷开关均为断路器的条件下,该方案能够实现快速故障区段定位、隔离和非故障区段的供电恢复。该方案充分考虑了与DG防孤岛保护及低电压穿越的配合与协调,各STU具备网络拓扑自动识别功能,能够根据网络拓扑的实时变化改变相关控制策略。最后利用所开发的STU装置,在实时数字仿真系统(RTDS)平台上对一个含DG的10 kV配电系统进行闭环测试。测试结果表明,该方案能够适应网络结构的变化,故障自愈时间在1 s以内。

Distributed Fault Self-healing Scheme and Its Implementation for Active Distribution Network

The traditional protection and control of distribution network face a considerable challenge due to the integration of a large number of distributed generators(DGs). In order to solve problems of active distribution network, a distributed fault self-healing scheme based on smart terminal unit(STU)is proposed. The scheme uses current differential protection and fault current amplitude comparison as the fault location principle, which is adaptive to the active distribution network with different DG types and penetration rates. Under the condition that all load switches are circuit breakers, the scheme can realize the fast location, isolation of faulted sections and the power restoration of non-faulted sections. The scheme fully considers the coordination with anti-islanding protection and low voltage ride-through of DGs. Each STU has the function of automatic network topology recognition, therefore can change the related control strategy based on real-time network topology. Finally, using the developed STUs, a closed loop test of a 10 kV active distribution network is carried out on RTDS platform. The test result shows that the scheme can adapt to the change of network structure, and the self-healing time is within one second.