Study on voltage distribution characteristic of a 363 kV fast multi-break vacuum circuit breaker

Abstract

Vacuum circuit breaker (VCB) has a longer life and shorter opening time than SF(6) circuit breaker, but current single-break VCB cannot be applied in high-voltage power system directly. Here, a fast 363 kV multi-break VCB design is presented and its voltage distribution characteristic and stray capacitors are analysed. A three-dimensional finite-element model of modularised hexa-break VCB composed of 12 vacuum interrupter modules installed on three series connected platforms is developed to calculate the voltage distribution and distributed capacitances. The result shows that the voltage distribution is uneven, and the first break shares the 67.974% of the whole applied voltage. On account of distributed capacitances parameters, an equivalent capacitance model with PSCAD is built to discuss the voltage distribution characteristic at different grading capacitance values, and the optimal grading capacitance value is determined to 10 nF.

Keywords

• finite element analysis
• vacuum circuit breakers
• distribution networks
• power system CAD
• capacitance 10.0 nF
• voltage 363.0 kV
• equivalent capacitance model
• PSCAD model
• three series connected platforms
• three-dimensional finite-element model
• stray capacitor analysis
• SF(6) circuit breaker
• vacuum interrupter modules
• fast multibreak VCB design
• fast multibreak vacuum circuit breaker
• distributed capacitance parameters
• voltage distribution characteristics
• modularised hexa-break VCB
• high-voltage power system
• current single-break VCB