ELECTRICAL-THERMAL-MECHANICS MODELING OF CIRCUIT BREAKER THERMAL TRIPPING UNIT USING MULTIPHYSICS PARTIAL ELEMENT EQUIVALENT CIRCUIT METHOD COMBINED WITH LUMPED BEHAVIORAL TRIPPING MECHANISM MODEL

Main components of any electrical circuit are a power source that provides energy and a load that will use that energy for fulfilling the designed purpose. Wires are the most common means used to enable this energy transfer. To enable controlled energy transfer switch is used. Unexpected working situation can happen, that can cause rise in power demand from power source fare beyond the normal working conditions. To protect actors of the circuit from permanent damage fuses and circuit breakers are used to interrupt current path in case of over-current conditions. Most of the common circuit breakers use two types of tripping, thermal tripping for slight increase of load demand, and magnetic tripping if load increase is rapid and intense. Parametric electrical-thermal-mechanics partial element equivalent circuit model of the thermal tripping unit was developed, with possibility of exploring structural and material properties on final functional behavior. Multiphysics partial element equivalent circuit method (muphyPEEC) was used for deriving bimetallic strip model. It was combined with lumped and behavioral model for other parts of trip mechanism to emulate circuit breaker functional behavior. LTspice circuit simulation software is used for simulations on combined circuit breaker thermal tripping model.