Research on Monitoring of Winding Deformation of Power Transformer by On-line Parameter Estimation about Leakage Inductance

Transformers are required to demonstrate the ability to withstand short circuit currents. Over currents due to short circuit can cause winding deformation. A novel method for monitoring the state of transformer windings by identifying parameter of leakage inductance of transformer windings is presented in this paper, using least square techniques based on the equivalent circuit equation of transformer. The mathematical model is derived for on-line identification of winding electrical parameter. The identification errors coming from measuring error and model error are analyzed, and correcting model lowers the influence to result owing to model error. Test result indicates that the accuracy of parameter identification is high, which will not be influenced by the fluctuation of load and the changing of power factor. The method can be use to on-line detect the winding deformation effectively.