Analysis of Frequency Response Characteristics for CVT Over-voltage Monitoring Device under Different Load Conditions

Abstract

The accurate measurement of over-voltage is very important to ensure the safety and stability of power grid. Therefore, the frequency response characteristics of the over-voltage monitoring device employing capacitive voltage transformer (CVT) under different load conditions are tested and analysed in this paper, and the effect of load change on the frequency response characteristics without and with interior low-voltage capacitor is studied. The results show that: for the case without interior low-voltage capacitor, when the secondary side of CVT is no-load or rated load, the frequency characteristics are roughly the same, but when the load is heavy, the frequency characteristics are greatly different from the situation under rated load. When there is an interior low-voltage capacitor, the presence of the interior low-voltage capacitor has almost no effect on the frequency characteristics of CVT under different load conditions, and there is also little effect on the frequency characteristics of the interior low-voltage capacitor high-voltage side under rated load and no-load conditions.