Influence of electromagnetic transient physical models considering characterization characteristics on capacitive voltage transformers

Abstract

The equivalent circuit of traditional capacitive voltage transformers often faces the problem of complex data calculation and difficulty in grasping the internal nonlinear characteristics of transformers when constructing broadband models, resulting in poor power accuracy and stability. Therefore, with the help of electromagnetic transient physical models, the admittance sub model and nonlinear model are established by considering the frequency and saturation characteristics of the transformer. Based on the characteristics of capacitive voltage transformers, the model is processed in parallel to obtain a broadband coupling transformer model. The results showed that the error between the simulated current peak amplitude and voltage results of the model and the measured values was less than 2% and 1%, respectively. In the fault results, the harmonic error of the load voltage of the improved transformer was relatively small, far less than the error result of 2.73% of the traditional transformer. The proposed transformer model can better characterize its characteristics and has good transient response ability, providing reference tools and value for the operation and state detection of power systems.