A Method of Representing Isolated Operation of a Group of Induction Motor Loads

A method of representing the isolated operation of a group of induction motor loads using reduced order equations is presented. The method differs from the standard method of neglecting stator transients in that the rate of change of stator flux linkages are neglected in a reference frame whose speed varies as a function of the stator frequency. The accuracy of the resulting reduced order representation is investigated by comparing its response with that established using both the full order and standard reduced order representations. It is shown that in cases where there are no significant rotor transients involved, the reduced order model obtained using the proposed method provides a more accurate indication of the stator terminal voltages during isolated operation than the standard reduced order model derived by neglecting stator transients in the synchronous reference frame.