Calculation of Distributed Capacitances of Modularized Triple-Break Vacuum Circuit Breaker and Analysis on Its Grading Capacitors

To research voltage distribution characteristic of triple-break vacuum circuit breaker,a three-dimensional finite element analysis model of modularized triple-break vacuum circuit breaker composed of three fiber-controlled vacuum interrupter modules is built.The distributed capacitance values of modularized triple-break vacuum circuit breaker under vertical and U-shaped arrangements are calculated;the power-frequency voltage division test of modularized triple-break vacuum circuit breaker is performed;and voltage distributions under the two arrangements are measured.An equivalent capacitance model is introduced in to verify the accuracy of calculation results.Results of comparing measured test data with calculated values show that the relative error of voltage distribution is lower than 4%;under vertical and U-shaped arrangements the proportion of voltage distribution of the break at high voltage side is higher than 60%,so it is necessary to equip with suitable voltage sharing measures.Based on the value of distributed capacitance,static voltage distribution characteristics of modularized triple-break vacuum circuit breaker under different values of grading capacitors are analyzed.