Supplementary control for SVC to improve the converter commutation performance of HVDC

Considering the close relationship between commutation failure of HVDC and the voltage at inverter side, this paper studies the method to improve converter commutation performance with the help of SVC. In order to overcome the drawback of single-object control and further reduce the probability or commutation failure duration of HVDC system, the signal of AC line current as a supplementary control object is introduced to design a multi-object controller for SVC system. The CIGRE Benchmark HVDC model with SVC is simulated in electromagnetic transient program PSCAD/EMTDC to verify that the multi-object control strategy proposed is superior to single-object controller and realizes multi-object control to improve the system´s stability and converter commutation performance of HVDC.