Coordinated Frequency Control Strategy Design Between UPFC and Hybrid HVDC System

To improve the multi-infeed receiving end AC system’s frequency stability, this paper researches the coordinated method between UPFC and the cascaded hybrid HVDC system. Based on the original control loop, the additional active power control is added to the UPFC’s converter. The input of the additional control is related to the active power of the MMC in hybrid HVDC in case that the hybrid HVDC will cause the power flow fluctuation when its reference changes and fault happens. The simulation based on electromagnetic transient software shows that proposed method can adjust the AC line’s active power accordingly when the operation points of hybrid HVDC system changes. And the AC system’s frequency fluctuations can be improve a lot with the help of the coordinated strategy proposed in this paper.