A 3D calculation method for assessing the voltage distribution across breaks of HV circuit breakers

This paper presents a validated method to calculate the voltage distribution across breaks of HV circuit breakers. The method is based on the use of a software featuring calculation of three dimensional electric fields and assessment of stray capacitances between breaks and with respect to ground, which significantly affect the voltage distribution across the series breaks. Tests on 5- and 8-break circuit breaker were performed and the test results reveal that the real values measured agree to within 2% with the values calculated by software. A non-intrusive test technique which does not affect the stray capacitances with respect to ground, is also presented.