Phase co-ordinate model for analysis of isolated power systems

A computational procedure employing a phase co-ordinate reference frame has been used to study the transient behaviour of a group of induction motors when they become isolated from a large power system and fed from a standby generator. The model applied enhances flexibility in studying symmetrical and asymmetrical operating conditions, and shows how phase co-ordinate models can be used for detailed studies while retaining the physical configuration of the system. The model is easily adapted to investigate different system variables, e.g. current in each phase, node voltages, torque and speed recovery, generator field current, internal machine EMF and the effect of damper windings. These enable more accurate system behaviour to be predicted, and hence better system design and performance can be achieved