The project is designed to shut down the power supply when it is overloaded. Conventional circuit breaker like MCB based is on thermal bimetal lever trip mechanism. It is very slow and the trip time is dependent upon the percentage of overload. This project senses the current passing through a series element and the corresponding voltage drop is compared against the preset voltage proportional to the current by a level comparator to generate an output for the load to trip.
The concept of electronic circuit breaker came into focus realizing that conventional circuit breakers such as MCBs take longer time to trip. Therefore, for sensitive loads it is very important to activate the tripping mechanism at the shortest possible time, preferably instantaneously. This project is demonstrates fast tripping mechanism as against the slow one like MCB. Electronic circuit breaker is based on the voltage drop across a series element proportional to the load current, typically a low value resistor. This voltage is sensed and rectified to DC which is and then compared with a preset voltage by a level comparator to generate an output that drives a relay through a MOSFET to trip the load. The unit is extremely fast and overcomes the drawback of the thermal type. It uses a microcontroller from 8051 family.
Further the project can be enhanced by using a CT for galvanic isolation between mains and control circuit. Power electronic devices such as thyristors / IGBTs can be used for ultra fast operation compared to all the methods.