In order to limit commutation overshoots produced during the turn-off processes of LCC valves

it is necessary to install damping circuits parallel to thyristors. Parameter optimization of the damping circuit is an important part of valve design and the selected parameters should coordinate the turn-off electrical performance of the converter for its safe and reliable operation. Firstly

the calculation circuit of commutation overshoot is established

and the effects of high frequency parameters of related equipment on the valve voltage are analyzed. Then

the electrical performances that need to be considered in parameter design of the damping circuit are discussed in detail

and the influences of damping circuit parameters on the electrical performances are summarized. Finally

a method for optimizing parameters of the damper circuit is put forward by combining electromagnetic transient numerical calculation with nonlinear simplex method

and the reliability and flexibility of the method are verified by examples.