A Novel Method for Online Measuring the Capacity of Distribution Transformers

The work aims to develop a method for online measuring the capacity of distribution transformers (DTs). The relation expression of the short-circuit impedance (SCI) with respect to the voltage and current of the primary and secondary side has been developed through the analysis of the equivalent circuit model of transformer, in which the primary voltage is instead by ideal voltage source signal to avoid collect the primary voltage. And the online SCI is computed by fitting the obtained voltage and current data via the linear fitting technique. Furthermore, the online capacity of the transformer can be acquired by using the obtained SCI. The simulation based on Matlab/smulink are carried out, the results verified the feasibility and effectiveness of the novel method mentioned above with high accuracy.