Study of the large induction motor modeling to simulate squirrel cage broken bars and rings based on ATP
Jiang Jiandong · 2003
In this paper, based on the multi-loop theory, the voltage and flux linkage equations of the induction motor are deduced. By the new Park's transformation method for multi-rotor-phase system presented in this paper, the voltage and flux linkage equations are transformed in rotor-reference-frame. Now, the rotating EMF emerges in the voltage equations and the electrical inductance matrix is constant which makes it possible to construct the induction motor model in electromagnetic transient program such as ATP and EMTP. The torque equation is modeled with RC circuit. The electromagnetic torque and the mechanical torque are taken as plus and minus current source injecting the circuit respectively. The multi-loop equations in rotor-reference-frame are modeled with impedance coupling network. The voltage source that simulates the rotating EMF and the current source that simulates the electromagnetic torque are modeled in the MODELS of ATP. Then a new model to analyze the induction motor's squirrel cage broken bars and rings faults is developed in ATP and the faults' simulation methods are also given. The model can be used as a powerful tool to analyze the effect of broken bars and rings faults to large induction motor performances for the investigation of new diagnostic and protective methods, which has the advantages of strong practicability and conceptual clearness. Furthermore, the model can be used as a complete module of ATP. The simulations on a real motor are given and the results prove the effectiveness of the model.