Statistical Properties of Steady State Impulse Breakdown Voltage for Commercial Vacuum Interrupters

Two types of commercial vacuum interrupter were investigated. For each interrupter, the first impulse breakdown voltages after different operatìons were measured. From the test data obtained, it may be concluded that the probability of the first breakdown voltages of a vacuum interrupter after certain operations may be well defined by the Weibull probability distribution function, but the parameters of the functions are different for different types of interrupter and different kinds of operation. The probability distribution curves of the Weibull type of impulse breakdown voltages after operations of opening or closing with or without current were obtained experimentally. The characteristic values of these curves are calculated, and the impulse voltage breakdown properties for different operations are estimated and compared.