A method and system for judging secondary commutation failure

Abstract

The invention discloses a secondary commutation failure determination method and system; the method comprises the following steps: using an equivalent fault method to obtain an extinction angle of each inversion station after the fault occurs; determining the minimum extinction angle according to the extinction angle of each inversion station, the inversion station with the minimum extinction angle, and a commutation bus on which the inversion station with the minimum extinction angle is located; determining whether the minimum extinction angle is smaller than or equal to a critical extinctionangle or not; if yes, determining the inversion station with the minimum extinction angle has a commutation failure, and obtaining the voltage of the commutation bus on which the inversion station with the minimum extinction angle is located; determining whether the voltage of the commutation bus on which the inversion station with the minimum extinction angle is located is smaller than or equalto a commutation bus voltage critical value or not; if not, determining the commutation failure type of the inversion station with the minimum extinction angle is the secondary commutation failure. The method and system can determine the commutation failure type as the secondary commutation failure, thus improving the commutation failure prevention effect.

Description

technical field [0001] The invention relates to the technical field of power grids, in particular to a method and system for identifying secondary commutation failures. Background technique [0002] In the Multi-Infeed High-Voltage Direct Current (MI-HVDC) system, the inverter station may suffer from two voltage disturbances after the AC system fault occurs: (1) the voltage caused by the AC system fault itself Disturbance, defined as a voltage disturbance; (2) If a commutation failure occurs in an inverter station, it will cause the voltage of the commutation bus of the inverter station and other adjacent inverter stations to drop further. A further drop in voltage is a secondary voltage disturbance. Corresponding to the two voltage disturbances, there may be two commutation failure situations: (1) One voltage disturbance is enough to cause commutation failure in the inverter station, and the commutation failure in the inverter station is defined as primary commutation fail...

AI Technical Summary

Problems solved by technology

According to the two existing commutation failure judgments, it is impossible to judge the secondary commutation failure

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