Simulation modeling of high impedance transformer based on PSCAD with deep correlation of winding structure

Abstract

High short-circuit impedance transformer is widely used because of its advantage in limiting short-circuit current. Among the two types of high short-circuit impedance transformers commonly used, high-voltage winding built-in type frequently occurs zero-sequence over-current protection maloperation during no-load closing, while another type of low-voltage series reactance transformer is rarely reported. The main difference between them lies in the winding structure. However, the existing transformer simulation models can hardly reflect the difference. Through research, the equivalent circuit model which can reflect the difference of winding structure through flux linkage analysis is established, the method of building simulation model of high impedance transformer based on EMTDC/PSCAD is put forward, and the accuracy of the model is verified through dynamic simulation test, which provided a powerful tool for the research of high impedance transformer. Finally, the difference in inrush current characteristics of different high-impedance transformers are compared, and the reasons why the built-in transformer is easy to malfunction is explained.