COMPUTER-AIDED CALCULATION OF THE STEADY-STATE THERMAL PERFORMANCE-CHARACTERISTICS OF LOW-VOLTAGE CIRCUIT-BREAKERS

A discrete thermal network is given as an equivalent circuit of the st eady-state thermal performance characteristics of circuit breakers. Th e immediate environment of the enclosure and the feeders of the unencl osed switching device are the boundaries of the equivalent circuit, wh ich specifically models the central phase of a three-phase circuit bre aker Computer simulations make it possible to analyse the thermal syst em performance in rated service. Selected examples prove the high qual ity of the model and the efficiency of the described method of calcula tion.