配电网故障下的STATCOM运行分析

Operation Analysis of STATCOM under Distribution Network Fault

电网发生故障时,故障电流大,三相功率分配不相等,造成三相相间电压不均衡,影响系统稳定。应用静止同步补偿器(STATCOM)能发出或吸收满足系统要求的有功和无功电流,提高电网运行的安全水平。文章首先分析了故障时电压和电流的各序分量特点,探讨了对称和不对称故障时的系统工作特性。然后通过仿真,设置一个配电网络分别发生单相接地、两相相间短路和三相接地故障时,观察系统的运行情况,进而通过调节STATCOM控制正序基波电流,使STATCOM在故障期间提供一定的有功和无功支持,保持系统电压的稳定,维持系统的安全稳定运行。

When the power grid fails,the fault current is large and the power distribution among three phases is not equal,which results in the unbalanced voltage of three phases and affects the stability of the system.The application of static synchronous compensator(STATCOM)can emit or absorb the active and reactive current which meet the requirements of the system and improve the operation safety of the power grid.Firstly,the characteristics of the sequence components of voltage and current are analyzed,and the operating characteristics of the system under symmetric and asymmetric faults are discussed.Secondly,through simulation,a distribution network is set to have a single-phase grounding fault,a two-phase short-circuit fault and a three-phase grounding failure respectively,and the operation of the system is observed.During the failure period,the positive sequence current is controlled by adjusting the positive sequence voltage of STATCOM,so that STATCOM can provide certain active and reactive power support,keep the system voltage stable,and maintain the safe operation of the system.