Calculation on stray capacitances and impulse voltage distribution of HVDC converter valve

The transient voltage distribution performance is one of the key electrical characteristics of HVDC converter valves. Stray capacitances of converter valves are the main factor resulting in uneven distribution of transient voltage, therefore accurate calculation on stray capacitances is of necessity and significance. A set of calculation method was proposed including windowing truncation, shielding effect, reuse technology, etc. Relative theoretical derivations were completed; results showed that the calculated capacitance values are larger than the actual ones, and thus proved to be conservative and credible. Furthermore, based on the field-circuit coupled method, an equivalent circuit for transient voltage was build; and calculation on impulse voltage distribution was performed. Finally, calculation and test results verify the feasibility of the proposed calculation method for stray capacitance and voltage distribution.