Static Voltage Distribution of a Multi-Break Mechanical Switch for Hybrid HVDC Breaker

The hybrid high voltage direct current (HVDC) breaker is a key equipment of the DC grid. The high speed mechanical switch is a key component of the hybrid HVDC breaker and has a number of serially connected switch units. The serially connected units should divide the voltage uniformly. The static voltage distributions and distributed capacitances of a 500 kV hybrid HVDC breaker mechanical switch are studied in this paper. A three dimensional finite element model, considering the actual dimension parameters of six 110 kV high speed mechanical units in serially vertical arrangement, is established to study the static voltage distribution characteristics and capacitance parameters of a 500 kV multi-break high-speed mechanical switch, with six 110 kV high speed mechanical switches in serially vertical arrangement. The calculated results indicate that, under vertical arrangement, from the point of capacitive voltage distribution, the static voltage distributions of the six mechanical switch units are non-uniform, and the high voltage unit is more than 75% of the whole voltage.