Identification Method of Transformer Leakage Reactance Based on Recursive Least Squares

Power transformer is an important component of the power system. When the transformer winding is deformed, the leakage reactance parameters will change. Therefore, higher requirements are put forward for the identification method of leakage reactance parameters. In this paper, the recursive least square algorithm is proposed to accurately and quickly identify the equivalent leakage reactance parameters by using the sampled values of voltage and current at the primary and secondary sides of the transformer and the relationship between the difference equation of transformer steady-state operation and reactance parameters. The simulation of a single-phase transformer found that the identification result is accurate, and this method can also monitor the transformer winding state online. The results are not affected by the changes in transformer load and power factors and the Fourier filtering algorithm can effectively eliminate the influence of primary voltage harmonics on the identification results.