Individual-Phase-Control SVC for HVDC Link with Weak Receiving AC System

This paper presents an individual-phase-control (IPC) SVC compensation strategy for HVDC link with weak receiving AC side. Both uniform-phase-control (UPC) and IPC compensation policies are investigated. The paper employs PI control for the phase susceptance determination and star-delta transformation for line to line susceptance calculation. Inverter bus voltage behavior is studied and comparison is made for UPC and IPC polices considering remote asymmetric failure in the inverter AC system. The result shows that the non-fault-phase voltage will exceed rated voltage, which will deteriorate voltage performance and aggravate voltage imbalance; the fault-phase voltage will be compensated little which will lead to commutation failure when SCR of AC system is less than 1.5, if using UPC policy. While the IPC SVC compensation strategy will make the non-fault-phase voltage stay at rated voltage and fault-phase voltage compensated more, which will inhibit voltage imbalance and commutation failure effectively.