Research On Modeling And Transient Characteristics Of Electronic Current Transformer

In recent decades, with the development of optical technology and power electronics science and technology, human society entered the digital age gradually, the development of technology also promoted the progress of the power industry, further more promoted the research and development of electronic transformer technology. Electronic transformer can directly provide digital signal to measuring protection equipment, it can simplify the secondary equipment, and improve the accuracy and reliability of the power grid system, so the electronic transformer gradually begin to use widely. But in ultra-high voltage and extra-high voltage power system, short circuit current aperiodic component decay time will be long, However the removal of the fault time requires short, at this time electronic transformer in transition work state, so the data of electronic transformer in the transient process need magnetization curve, analysis of transient process parameters, and make model for transient process of electronic transformer. Above all, those parameters are very important to power grid safety.Magnetization fitting and the model of transient characteristcs is very important to the electronic grid safty, the author of this paper propose researching on TPY current transformer magnetization fitting and modeling analysis, based on the transient current transformer data, analysis the transient charateristics model.Main work is included as the following aspects:(1) For current transformer equivalent model of Rogowski coil under different working conditions, analysis of the theoretical calculation method and the applicable region of different model parameters(2) Use the matrix laboratory to fit the TPY current transformer data, verify the feasibility of the least square method in current transformer transient modeling, and then analyze the transient characteristic measurement error.(3) Study the theory of current transformer transient characteristic parameters, including secondary time constant, excitation inductance and remanence coefficient. Analyze the algorithm of magnetization curve fitting. Including least squares fit method and BP neural network, and compared the advantages and disadvantages of data fitting method.(4) Build TPY mathematical model, analysis TPY current transformer how to respond when a circuit malfunction, Because of the mathematical model is the nonlinear equations, it can not show the explicit express, so use the numerical calculation principle to solve this problem. In order to improve the calculation accuracy, this project adopts the 4 order Rungle-Kutta method to get the result.