Statistical Approach to the Power Testing of High Voltage Circuit Breakers

The random behaviour of circuit breakers requires the application of testing methods based on statistical approach. Technical information provided by different testing procedures are compared. Experience achieved during years of comparison tests between direct and synthetic methods is discussed on statistical basis. The "up and down" method is proposed as a suitable mean to investigate the circuit-breaker performance with small samples. The power of this method is stressed to explore the low failure probability region.