Soft Open Point (SOP) is a power electronic device installed in place of normally open points in electrical distribution networks. This paper investigates the dynamic performance of a medium voltage (MV) distribution network with a connected SOP, under grid side AC faults. Use of sequence networks was extended to include SOP, such that conventional fault analysis technique can be used on a distribution network with SOP. A Fault-Index was defined using symmetrical components of voltages measured at the grid connection point of the SOP. The network performance was investigated under a line-to-ground, a line-to-line and a three-phase fault. The behaviour of the network was analysed under different control schemes and various operating scenarios of the SOP. Furthermore, the dependence of the sequence voltages and currents on the SOP set points was investigated. Simulations were carried out on an 11 kV generic UK distribution network model developed in PSCAD/EMTDC. Results show that the convectional fault analysis technique is applicable on a network with SOP, regardless of the SOP control mode. The Fault-Index, defined based on the local voltage measurements, was effective in detecting the presence of an AC fault in the MV distribution network. In addition, the need for a non-current based detection method is illustrated.

软断开点（SOP）是一种电力电子设备，用于代替配电网络中的常规断开点。本文研究了在电网侧交流故障下具有连接的SOP的中压（MV）配电网络的动态性能。顺序网络的使用已扩展到包括SOP，从而可以在具有SOP的配电网络上使用常规故障分析技术。故障指数是使用在SOP的电网连接点测得的电压的对称分量定义的。在线对地，线对线和三相故障下研究了网络性能。在SOP的不同控制方案和各种操作方案下分析了网络的行为。此外，研究了顺序电压和电流对SOP设定点的依赖性。对在PSCAD / EMTDC中开发的11 kV通用UK配电网络模型进行了仿真。结果表明，对流故障分析技术适用于具有SOP的网络，而与SOP的控制模式无关。根据本地电压测量值定义的故障指数可有效检测MV配电网络中是否存在AC故障。另外，示出了对基于非电流的检测方法的需求。根据局部电压测量值定义的电压有效检测MV配电网中是否存在AC故障。另外，示出了对基于非电流的检测方法的需求。根据局部电压测量值定义的电压有效检测MV配电网中是否存在AC故障。另外，示出了对基于非电流的检测方法的需求。