Abstract:

Dynamic reactive power compensation devices are effective in improving the voltage stability of the receiving end.In this paper,a fast proximate calculation method of dynamic reactive power peak demand in inverter after large disturbances is proposed to determine the capacity of dynamic reactive power compensation devices.In the investigation,first,the direct-current control mode is determined and the control links that play a major role in HVDC ( High-Voltage Direct Current Transmission) during the failure recovery are retained after a detailed analysis of HVDC control system.Next,the elements that determine the dynamic reactive power characteristics of the inverter are defined and the impact of disturbance severity on the elements is analyzed,which helps to clarify the mechanism by which the peak value of dynamic reactive power consumption of the inverter is relatively fixed.Then,some system parameters are properly processed without considering the impact of disturbance severity to estimate the dynamic reactive power characteristics after different AC voltage drops with a unique peak curve.Moreover,the differential equitation describing the simplified HVDC system is presented and the dynamic reactive power peak demand is obtained.Finally,the estimated demand value is used to determine the capacity of the dynamic reactive power compensation device installed in the receiving power network.Simulated results on Chu-Sui HVDC PSCAD/ EMTDC model show that the estimated dynamic reactive power peak is correct,and that the proposed design method of dynamic reactive poser compensation devices is feasible.

Key words: inverter, high-voltage direct current transmission, dynamic reactive power, HVDC control, proximate calculation