Transient overvoltages in electrical motors during sequential pole closure

This paper addresses the problem of transient overvoltages in electrical motors during sequential pole closure in industrial installations. A computer model that includes the circuit breaker, high-voltage cable and electrical motor is proposed. Multiconductor transmission line theory and modal analysis are applied to the components and the piecewise Fourier transform is used to simulate sequential pole closure. The mechanism of sequential pole closure is analyzed including parallel capacitors and series inductors. Critical times for switching transients are calculated. Finally, the effect of several system and machine parameters on transient overvoltages is investigated.