Switching transients during energizing capacitive load by a vacuum circuit breaker

Both experimental investigations and computer simulations of multiple prestrikes and associated prestriking overvoltages during energizing a capacitive load (capacitor bank or unloaded cable) by a vacuum circuit breaker are presented. It has been found that the prestriking overvoltage is associated with multiple prestrikes, and the circuit parameters or arrangements play important roles on the severity of the prestriking overvoltages. A simple computer simulation program is established and verified with the experimental results. Further simulations of several probable practical cases are also provided. Normally, overvoltages will not exceed 3 PU, but higher values are possible in special cases due to resonances in cable-line-cable networks