Experimental realization of microcontroller based programmable miniature cost effective circuit breaker

Abstract

Miniature circuit breaker (MCB) is an electrical protection equipment. Generally it is used in households as an over current circuit breaker to ensure safety from electrical hazards like outrageous fire accidents arising from electrical short circuit. These kinds of electrical hazards occur because the amperage of these circuit breakers are fixed and we cannot change the tripping current anytime to endure the newly added or removed electrical loads. This paper reports the experimental realization of a numerical overcurrent relay using, primarily, a microcontroller and a micro current transformer (CT) which is compatible with smart grid technology and high voltage system like electric vehicle. In this newly designed numerical over current relay (NOCR) the user can change the set current and the sensitivity of the system just by twisting two different knobs. Thus this system ensures advance security against electrical hazards than a normal MCB. It will obtain, trial and covert analog current signals hooked on digital form of a power system in real time. Solid state switch (MOSFET switch) has been opted as circuit breaker in order to enhance system effectivity. This newly designed system can detect a fault or over current with 100% accuracy and the operating time (OT) calculated by this relay is 99.57% responsive to the theoretical calculation. All the components used to assemble this system are off the shelf; hence engender an economic and portable over current relay than any other commercially available system.