HVDC circuit breakers are the key protection equipment for HVDC power grids. In the main branch of hybrid HVDC circuit breaker

the fast mechanical switch adopts the form of series multi-break to ensure the requirement of operating rapidity. Choosing appropriate voltage-sharing component parameters is an important guarantee for the fast mechanical switch to meet the static and dynamic voltage withstand property. But it may be affected by many factors in actual operation

and the concerned research results are few. Taking the series six-break 550 kV fast mechanical switch as an example

which makes up the ±500 kV hybrid HVDC circuit breaker in the Zhangbei four-terminal DC grid

the voltage distribution characteristics and distributed capacitance parameters were simulated by the three-dimensional finite element model. The influence of the factors on the voltage-sharing components’ parameters

including single-break fault

asynchronous breaking

and the influence of shield fittings

were simulated. The research results show that

single-break fault and asynchronous breaking have a little effect on the configuration of voltage-sharing

the influence of the shield is positive but small. And the parameter check considering multiple factors is required finally. The research results can provide guidance for the voltage sharing design of series multi-break no-arc fast mechanical switch.