Modelling of squirrel-cage induction motors for electromagnetic transient programs

The authors discuss the modelling of the squirrel-cage induction motor. The experimental measurements on motors of different rated power, 1-90 kW, clearly show that the single-cage model does not fit the torque-speed curve adequately. Consequently, when the speed varies in a wide range, only the double-cage model can fit the curve well with the squirrel-cage induction motor. The equivalence between the two most commonly used double-cage models in the literature is studied, and a method to find the equivalent parameters is developed. In addition, the induction motor modelling in the PSCAD/EMTDC and EMTP-RV simulation programs is examined, and the inaccuracies resulting from the use of manufacturer data are discussed.