A methodology to develop induction motor model from modal measurements for EMTP

Electro-magnetic transient program (EMTP) is worldwide used for transient analysis simulation. It is well known it cannot deal with modal value directly. Therefore, for transient analysis it is necessary to convert measured modal impedances into phase domain. The over-voltage phenomenon is usually described using the traveling wave and reflection phenomena due to control in variable speed drive system consists of PWM Inverters. A motor winding may partially discharge due to an inverter surge giving a significant impact on its insulation, and lead to a breakdown.A soft switching technology has been developed to suppress the surge voltage. It requires to evaluate the surge in advance. For this, an accurate prediction of the surge voltages at the terminals of the motor becomes very significant. Models for the connecting cable and the motor are required for the prediction. This paper emphasize on induction motor model using the theory of natural modes of propagation. The methodology to develop motor model for EMTP is studied and discussed in detailed