A Novel Capacitor Voltage Transformer Based on Isolated Conduct Effect and its Stability Under Non-rated Condition

Capacitor voltage transformer (CVT) is used in power systems with voltage level above 10kV to substitute traditional electromagnetic voltage transformer due to its advantages of simpler insulation design and lower cost. Meanwhile CVT has disadvantanges including respective low accuracy and limited bandwidth. In order to improve the measurement performance, a design of equipotential shielding capacitor voltage transformer based on isolated conductor effect is presented in this paper. The principles of designed CVT are studied by proposing electrical model and transmission characteristics. Furthermore, the electrostatic field model as well as the principle and accuracy of CVT is simulated using COMSOL FEA tool. A compressed-volume equipotential shielding CVT is designed to measure the power frequency and transient traveling wave signal under non-rated condition. Measurement performance of the equipment under standard and non-rated condition is studied through experiments, and a field compensation method for measurement is given at last.