The Steady-State Error Analysis of New Type High-Voltage EVT and Its Modification

A new principle and method to measure high voltage by detecting current of high-voltage capacitor were proposed, a new type of high-voltage electronic voltage transformer(EVT) based on this method was designed. The steady-error of the EVT was analyzed considering the effects of capacitor temperature and the power frequency. For the temperature effect, thermistor temperature sensor was used to establish temperature compensation and introduce the error correction, so as to reduce the ratio error of EVT. The equivalent circuit of EVT had established, based on this and the signal processing circuit, the relation between primary and secondary voltage was deduced. The possibility of adjusting the frequency characteristic by changing the EVT´s parameters was proved by the MATLAB simulation. Finally, building the steady-error experimental system, the result of high-voltage test shows that these measurements are feasible.