Research On The Modeling Method Of Broadband Circuit For Capacitor Voltage Transformer

Capacitor voltage transformer (CVT) as a key equipment in the substation, is easyinfluenced by the over-voltage impact or electromagnetic interference. In the study ofrelated issues to the transient, establish a precise, viable and general broadband CVTmodels have a practical significance in research of the power system over-voltage orother related issues.Precise measurement of the sample data is the basis of modeling. In order toovercome the mismatch error which caused by the non-test port when use the two-portnetwork to measurement Scattering parameters of the CVT, this paper presents aderivation of the two-port VNA to measure the multi-port (three-port, four-port) iterativecorrection method of the network. And based on the method gives a measurementprogram in the CVT scattering parameters which considering the mismatch factor of thetermination load, related to the measurement, analysis, correction and verification.This thesis focuses on the method which considered the spurious andfrequency-dependent properties in broadband CVT model, this method based on the CVTtraditional equivalent circuit model, and combined with the black-box methods and themeasured data, established a CVT broadband equivalent circuit extended new model. Thelossy two-port model does not contain active elements, and is able to meet both endswhile pick the requirements. Simulation and comparison of the measured data illustratethe feasibility of modeling methods.