Non-intrusive Measurement of Transient Electric Field Distribution in HVAC GIL

Measuring the electric field distribution will provide exact information for the design and the safe operation of electrical devices. A simple but effective technique is developed in this paper to measure the transient electric field distribution by fabricating a micro-sized sensor on the grounded (GND) electrode. Both the parameter selection and the fabrication technique are critical for ensuring the non-intrusive measurement. By experiment, the measured electric fields in time domain have exactly the same waveforms as those of the applied AC and impulse voltages, and their spatial distributions are in good agreement with the theoretical calculation results, which proves the correctness and effectiveness of the measurement system. In the future application, the measurement electrodes of the sensor can be designed to be in smaller size and in array form for a more precise measurement. This technique has the potential to be applied in the electric power system for the dynamic monitoring and the defect location of electrical devices.