PEOPLE PROTECTING GROUND FAULT CIRCUIT BREAKER UTILIZING WAVEFORM CHARACTERISTICS

摘要

46,196 PEOPLE PROTECTING GROUND FAULT CIRCUIT BREAKER UTILIZING WAVEFORM CHARACTERISTICS A ground fault circuit breaker is provided which includes means for sensing ground fault current and for analyzing the waveform of the ground fault current. An operating mechanism automatically separates the contacts of the circuit breaker upon detection of ground fault current waveforms corresponding to the waveform of current passing through human skin. In a preferred embodiment, means are provided to synchronously detect the third harmonic component of ground fault current using phase and amplitude information to determine the presence of a ground fault path through human skin. Alternatively, means are provided to sense peak and average values of ground fault current and to trip the breaker whenever the ratio of peak to average ground fault current exceeds a predetermined level. In another alternative, the slope of the ground fault current at zero crossing is detected and compared to the ground fault current peaks. Whenever the ratio of peak current to zero crossing slope exceeds a predetermined level, the mechanism of the breaker is tripped.