风电场汲流效应对配电网故障电流的影响

Impacts of the shunting effect of wind farm on fault current of distribution network

首先研究了风电场故障电流特性及其影响因素。然后考虑过渡电阻,推导了风电场接入点上游故障电流与风电场输出电流的数学关系式,分析了风电场对上游故障电流的汲流效应。最后以PSACD/EMTDC为仿真平台,搭建了含风电场的配电网模型,仿真研究了风电场接入配电网对接入点上游故障电流和继电保护的影响。研究表明,由于风电场汲流效应,接入点上游的故障电流会因为风电场的接入而减小,且严重时会导致上游电流保护I段的保护范围减小,II段保护灵敏度减小,容易造成保护的拒动。

Firstly,the characteristics of the fault current of wind farms and its influencing factors are researched.Then considering the transition resistance,the relational expression between fault current at the upstream side of wind farm network-connected position and output current offered by the wind farm is derived and the impact of the shunting effect of wind farm on upper stream fault current is analyzed. A simulation model of distribution network containing wind farm is built on the platform of PSCAD / EMTDC,and influence of wind farm accessing to distribution network on fault current and relay protection at the upstream side of wind farm network-connected position are simulated and studied. Research results show that on account of the shunting effect of wind farm,the fault current at the upstream side will decrease. When the situation is serious,it is connected to the system and the relay protection will refuse action because of the shortened I-zone and the insensitive II-zone at the upstream side of wind farm network-connected position.