Complex multifunctional relay system and control method therefor

Provided are a complex multifunctional relay system capable of complexly performing an overcurrent blocking function, an arc blocking function, and an earth leakage blocking function by a relay circuit, and a control method therefor. The complex multifunctional relay system includes an AC circuit including a hot line and a neutral line, a power control means connected in parallel to the hot line, insulation differential amplifiers circuit-connected to the hot line and the neutral line through current shunts, a microprocessor connected to the power control means and the insulation differential amplifiers to perform monitoring and control the power supply of the power control means, a first comparator connected to the current shunt and the insulation differential amplifier and connected to the microprocessor so as to check ground fault, and a second comparator connected between the current shunt/the insulation differential amplifier and the microprocessor so as to check arc fault.