Study on the Calculation of the Commutation Overshoot of HVDC Valve BasedonthePiecewise Fitting of Reverse Recovery Current of Thyristor

Abstract: Thyristor, RC damping circuit and valve arrester are the main part of primary loop of UHVDC valve, determining the cooperation the parameters of the three types of devices is the chief work in the electrical design of UHVDC valve, in this paper, the mechanism of the commutation overshoot was revealed, the interaction effect of the three types of devices was also confirmed, then the circuit differential equation was established ， and the equation was solved by Piecewise fitting the reverse recovery current of thyritor, the precision of the calculation method that was put forward in the paper was proved by comparing the calculation results with the test results