Influence of HVDC control on HVDC reactive power overshoot after large disturbance

This paper presents a study of HVDC reactive power overshoot which presents unfavorable reactive load disturbance to AC power system and may result in transient voltage instability. The key idea of this paper is HVDC control has a strong effect on HVDC reactive power recovery characteristic. Based on an actual HVDC project and the PSCAD/EMTDC simulation platform, this paper systematically studies the influence mechanism and pathway of HVDC control on HVDC reactive power overshoot after the AC bus in inverter station is subjected to faults, and also refines related influence rules of control parameters. By keeping firing angle unchanged, the inherent HVDC reactive power recovery characteristic is analyzed, and the key control links that affect reactive power overshoot are excavated sequentially, containing constant extinction angle control (CEA), voltage dependent current order limiter (VDCOL) and transient current control function. According to the simulation results, the influence rules of parameters of the above-mentioned key control links on the overshoot magnitude are summarized, which contributes to HVDC control strategy optimization of enhancing the transient voltage stability.