Improvement of Leakage Trip Operation Time through Electronic Circuits Analysis of the Circuit-Breakers for Human Body Protection Against Electric Shock

Abstract

This paper analyzed the electronic circuit and investigated the electrical properties to improve the tripping time of domestic ELCB. The operating time of the ELCB showed different values according to the location of voltage waveform and the duration time of leakage current at the instant when the leakage input signal is occurred under rated voltage, and the maximum value of the time measured was up to 26 ms. This was due to the time delay of the IC characteristics used in the electronic circuit which is operated only for the reverse half cycle of the sine wave. The authors developed a prototype circuit breaker with optimized delay element and performed an operation test, through which reduction of the ELCB trip time required for the circuit breaker standard by half was possible. Reduction of operating time of ELCB implies improvement of human body protection against electric shock. It is expected that production of safer ELCB will be possible in the future if more advanced and reliable electronic circuit or IC is developed.