A numeric simulation approach to field protection design in wound-rotor brushless synchronous machines

A proper choice and dimensioning of field protection circuitry represent a delicate issue in the design of wound-rotor synchronous motors and generators. In this paper computer simulations are discussed as a tool to investigate rotor circuit electrical behaviour during faults or abnormal transients. Quantitative evaluation methods are proposed to assess the appropriateness of rotor protection equipment in such transient scenarios as short circuit, pole slipping and voltage dip events.