In order to avoid the commutation failure due to the decrease of extinction angle of inverter caused by voltage rise of converter bus at sending end,the occurrence mechanism is studied from the variation characteristics of electrical quantity and the exchange characteristics of reactive power respectively.Based on the derived expression of extinction angle,it is found that the voltage rise of converter bus at sending end will increase DC current,which will lead to the decrease of extinction angle.At the same time,the increase of DC current will lead to the increase of reactive power consumption of inverter,resulting in voltage drop of converter bus at receiving end,further leading to the decrease of extinction angle and inducing commutation failure.Therefore,a measure to suppress commutation failure by improving controller at sending end is proposed.This measure increases the trigger angle of rectifier when the voltage of converter bus rises at sending end to suppress the rise of DC current and increases the reactive power consumption of rectifier,so as to slow down the voltage rise of converter bus at sending end.Based on PSCAD/EMTDC electromagnetic transient simulation platform,CIGRE HVDC benchmark model is used to verify the correctness of theoretical analysis and the effectiveness of suppression measures.
commutation failureconerter bus voltageDC currentreactive powerhigh voltage direct current transmission
维普
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