Simulation Research on Transformer Saturation SCAD Hysteresis Characteristics Based on PSCAD

In order to study the saturation hysteresis characteristics of transformers, based on the PSCAD platform, this paper uses the transformer Saturation module and the Hysteresis module to establish a transformer model of the saturation hysteresis characteristics and simulate and analyze the saturation parameters in the transformer module and the improved J-A model parameters. First, the influence of saturation parameters in the transformer Saturation module on the excitation current is analyzed; then the influence of the improved JA model on the shape of the hysteresis loop, the influence on the excitation current, and the influence of the degree of DC bias are analyzed. The simulation results show that The air-core reactance value has the greatest impact on the transformer excitation current; the nine parameters in the improved J-A theory have different effects on the hysteresis loop and the excitation current. Changing any parameter may cause the transformer hysteresis characteristics to occur change, so that the degree of DC bias of the transformer is changed. The transformer model in the PSCAD V4.6 platform considers both saturation characteristics and hysteresis characteristics. If its parameter settings can be close to the actual transformer operating parameters, it can simulate the excitation characteristics of the transformer under DC bias, which has engineering significance.

I. Introduction

With the rapid development of my country’s rail transit industry, the problem of subway stray current leakage has become increasingly serious. Stray current will flow into the grid through the grounding transformer^[1–2]. After the stray current flows through the transformer, the magnetization curve of the transformer core will shift, and the transformer will produce DC bias. DC bias will cause the transformer’s temperature rise, noise and vibration increase, excitation current distortion and other hazards. The phenomenon of DC bias has seriously threatened the safe and stable operation of transformers and even power systems^[3–6]. As for the study of transformer DC bias, the saturation hysteresis characteristics of the transformer core are the first to be studied.