Optical High Voltage Measurement Technique Using Pockels Device

This paper describes a new optical high voltage measurement technique to realize optical voltage transformers (optical VTs) through which high voltages up to 400 kV can be directly measured. A prototype of an optical VT using Pockels device in a multi-segmented arrangement is designed based on the numerical calculation of the electric field distribution. The response characteristics of the developed prototype are examined for ac, dc, and lightning impulse voltages, and these experimental results showed good agreement with theoretical estimations. An oscillatory component appearing on the output signal of the sensor for the impulse voltage application is successfully eliminated using a fast Fourier transform (FFT) digital filter. It is also found that the sensor can respond to fast transients with a rising time of 40 ns, which defines the frequency response bandwidth of the system from dc to several MHz.