Research on the transformer winding parameters real-time calculation method based on UD decomposition

The exact real-time identification of transformer winding parameters is favorable for the new transformer protection and winding deformation detection. In the paper a new model for the calculation of transformer winding parameters is presented based on the equivalent loop equations, the model is available no matter the transformer is under any normal operating conditions. In order to reduce the influence of the rounding error during recursion process, the least squares algorithm based on UD decomposition is adopted to solve the model. Various normal operating conditions of a sound transformer are simulated with ATP, and the presented method is verified with the simulation data. The analysis results show that the method is not affected by the operating conditions and the difference among the three phase winding parameters, and has fast convergence and high precision and stability.