Method and system for controlling commutation failure recovery of direct current system

Abstract

The invention discloses a method and system for controlling commutation failure recovery of a direct current system. Multiple direct current blocking accidents have already occurred since a direct current power transmission system puts into operation, and recovery control for commutation failure faults of the direct current system is extremely important for improving the safety stability of the system. According to the method for controlling commutation failure recovery of the direct current system, recovery tracks of commutation voltage and direct current are estimated by using a liner prediction method based on commutation voltage on alternating current side and direct current on direct current side; then, the minimum angle of an extinction angle is taken as a boundary of safe operation,the maximum values of delay trigger angles predicted by system recovery tracks in current state and after the faults are calculated respectively; and finally, the minimum value in the two values is taken as the maximum value in the final output amplitude limiting link of a delay trigger controller. The variation trend of system state is considered, dynamic amplitude limiting is adopted for a delay trigger angle command, the recovery of the direct current system can be prevented from being too quick to cause the occurrence of subsequent commutation failure in the recovery process of the faults.

Description

technical field [0001] The invention belongs to the technical field of electric power systems, and relates to the recovery control of converter station faults in traditional high-voltage direct current transmission projects, in particular to a DC system commutation failure recovery control method and control system based on recovery trajectory prediction. Background technique [0002] In actual operation, there have been many failures of single-circuit DC continuous commutation or multi-circuit simultaneous commutation failures in AC-DC hybrid systems due to AC system failures. Commutation failure failures will cause problems such as interruption of DC power transmission, overheating of converter valves, transformer bias, and relay protection malfunctions; at the same time, according to the current UHV DC control and protection strategy, when multiple consecutive commutation failures occur resulting in DC blocking. If multiple high-power DCs are lost at the same time, there...

AI Technical Summary

Problems solved by technology

Commutation failure failures will cause problems such as interruption of DC power transmission, overheating of converter valves, transformer bias, and relay protection malfunctions; at the same time, according to the current UHV DC control and protection strategy, when multiple consecutive commutation failures occur cause DC blocking

If multiple circuits of high-power DC are lost at the same time, there is a risk of system frequency collapse in the receiving end system, which may cause large-scale power outages

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