Voltage Sharing Design of Series Multi-break Mechanical Switch Considering the Whole Structure of Hybrid DC Circuit Breaker

Hybrid HVDC circuit breaker is one of the key control and protection equipment of HVDC power grid. In order to solve the problem of voltage sharing component design of series multi break mechanical switch for the hybrid DC circuit breaker, a test circuit was built to carry out the static and transient voltage distribution characteristics test of series double break mechanical switch. Based on the electrostatic field simulation, the distributed capacitance parameters were obtained, and the electromagnetic transient simulation model was established. The error between the simulation and the test results was within ±3%. Taking a typical ±535kV hybrid DC circuit breaker model as an example, considering the whole structure of the circuit breaker, the influence of the parameters of the voltage sharing component on the voltage distribution characteristics of the break was studied. It was suggested that the parameters of the six-break series mechanical switch voltage sharing component should be 100MΩ≤ voltage sharing resistance ≤1000MΩ, voltage sharing capacitance ≥4.83nF, and 100Ω≤ current limiting resistance ≤500Ω under the condition of voltage sharing coefficient ≥95%.The results of this paper prove the effectiveness of the field and circuit combination analysis method for the voltage sharing design of multi-break series mechanical switches, which can provide reference for the design of multi-break series mechanical switches of hybrid DC circuit breakers. © 2022 Chin. Soc. for Elec. Eng.