Alternative method for evaluation of damping circuit losses in HVDC thyristor valves

An accurate method for calculating the damping circuit losses in HVDC converter systems is proposed. It is based on an equivalent circuit representation of the converter system during each interval of conduction over a power frequency period. The results are compared with the results obtained by the approximate formula proposed by J.D. Ainsworth and with the results obtained using the second-order approximate model to simulate valve voltage oscillations during each commutation. The variation of damping circuit loss with bridge operating parameters and with the damping parameters is also analyzed