One kind of converter valve commutation failure determination method

The present invention relates to a method for determining the converter valves, specifically, to a thyristor valve commutation failure determination method. Firstly, by measuring the change in the operating state of the thyristor valve, such as the thyristor junction temperature Tj, the current drop rate di / dt, during turn-off withstand back pressure Vrr, on-state current IF and the like, the process determines a desired turn-off thyristor minimum off-angle] min; then, respectively, the minimum extinction angle of each thyristor] min and the system-level extinction angle γ is compared, statistical stage series thyristor commutation in the same number of failed phase arm, a comprehensive analysis of the bridge arm whether commutation failure occurs. The present invention is determined by the minimum off-angle γmin dynamically obtain the actual commutation failure criterion; help HVDC control and protection system is adjusted off control margin.