The Research On Electronic Voltage Transducer’s Tranfer Characteristics To Traveling Waves

Currently the electromagnetic voltage transformer owns good transient response to low-frequency voltage signals. To satisfy the needs of traveling wave based technology and apply the technical advantage of EVT to improve traditional protection, it’s necessary to do further research for components of EVT, especially transfer characteristics of high-frequency signal. The main idea of this paper is to establishes accurate models of EVT by analyzing its equivalent circuit, appropriately design parameter and finally validate theory by experiments. Main work is as follows:The implementation of principles of EVT with capacitive divider (C-EVT), resistance divider (R-EVT), and inductance divider (L-EVT) will be introduced in detail.The paper analyzes equivalent circuits of R-EVT,C-EVT and L-EVT, establishes the equivalent circuit models in Matlab, also studies their frequency characteristics in designed parameter.Because of the special characteristics of C-EVT’s output, following circuits of C-EVT, amplifying circuit,integral circuit are also established in this paper. The function of ideal integrator and modified integrator is compared. The frequency characteristics of the whole circuit is analyzed with designed parameters. The models’ transfer characteristics of base frequency signal and traveling wave signal are simulated by model building and simulation.The equipments of C-EVT and L-EVT are produced. In order to do relevant tests, an experimental platform is built. Based on the experimental platform, we measured the parameters of the equipments and do the transfer tests of base frequency signal, high frequency signal and singular signal. Analysis of experiment results verified the transformers’ principle and the equivalent circuit models.