基于潮流分布特性的含小水电配电网孤岛就地划分策略

Local Division Strategy for Isolated Island of Distribution Network with Small Hydropower Based on Power Flow Characteristic

小水电集群接入的配电网发生严重故障时,解列后形成的孤岛电网与主网相比规模较小且功率支撑不足。为了确保孤岛系统的电能质量和运行稳定性,对含小水电集群配电网故障后的孤岛划分问题进行分析,研究基于潮流分布特性的配电网孤岛就地划分策略。首先对含小水电集群配电网模型进行分区等效与简化,再根据各区段潮流的大小,按照正时限特性确定分段开关动作时间,并根据孤岛频率变化率越限情况进行切机、切负荷。最后,在PSCAD/EMTDC平台搭建含小水电集群的IEEE 14节点配电网模型进行仿真验证,结果表明所提策略可以在不依赖通信的情况下生成功率差额最小孤岛,并能保证所生成孤岛系统的频率稳定。

The island grid formed due to disconnection when the distribution network with small hydropower clusters is in case of extreme failure is comparatively smaller than the main grid.To ensure power energy quality and operation stability of the island system,this paper makes an analysis and studies a local division strategy for the distribution network based on power flow characteristic.It firstly carries out partition equivalence and simplification of the distribution network model with small hydropower clusters,then determines the operation time of segment switches in accordance with the positive time limit according to the size of the section power flow,and cuts the load based on the off-limit situation of the island frequency change rate.Eventually,an IEEE 14 distribution network model with small hydropower is built on the PSCAD/EMTDC platform to verify the proposed method.The simulation results show that the proposed strategy can generate the island with the minimum power rate difference without relying on communication,and ensure frequency stability of the island system.