SYNCHRONIZING AND DAMPING TORQUES OF SATURATED DUAL-EXCITED ALTERNATORS

The problem of increasing the dynamic and transient stability limits o f power systems is given great attention by the power utilities. Use o f the dual excited alternators is one of the suggestions for enhancing the stability of the power systems. This pager presents an accurate d ynamics stability study for such alternators. Evaluation of stability is performed based on calculation of the synchronizing and damping tor que coefficients. The alternator is represented by a detailed circuit model which incorporates properly the saturation effects under steady- state and dynamic conditions. Based on this model, the torque coeffici ents have been calculated using a least square algorithm which is unre stricted to the degree of complexity of the system. Limits of dynamic- stable operation have been determined under the action of both the AVR and AAR These are integrated with thermal and mechanical limits to de termine the capability diagram of the dual-excited alternator.