Emergency Control Method of the Reactive Compensation Devices near the Inverter Stations to Reduce Power Impact of HVDC Commutation Failure on the Power Grid

摘要

The AC fault of receiving end power grid can cause HVDC continuous commutation failure, bring very high power impact on both of the sending and receiving end power grid, which will threaten the safe and stable operation of the AC-DC interconnected system. The voltage drop of converter station caused by AC faults is an important reason for HVDC continuous commutation failure. By preventing the transmission of AC fault, that is, enhancing reactive power support capability of AC power grid is an important measure to suppress HVDC continuous commutation failure. So after analyzing the dynamic characteristics and mechanism of HVDC commutation failure caused by AC faults, an emergency control method of the reactive compensation devices near the inverter stations is proposed in this paper to decrease the voltage drop under faults and reduce power impact of HVDC commutation failure on the whole system. Firstly, based on the characteristics of the actual power grid and the distribution of the reactive compensation devices, the devices which are involved in the emergency control measures inside the inverter station and nearby are determined. Secondly, the sensitivity of each device switching to the bus voltage of converter station are calculated. Then according to the sensitivity index and the drop or rise condition of transient voltage of converter station, the emergency control amount of the compensation devices is calculated. At last, the effectiveness of the proposed method is verified by the simulation of actual power grid.