Comparison of different characteristic parameters acquired by UV imager in detecting corona discharge

Abstract

UV imager has promising application prospect in the detection of corona discharge because of its advantages, such as high sensitivity, intuitive and non-contact discharge detection. In order to make better use of ultraviolet imager to detect corona of the high voltage electrical equipment, experiments are carried out to observe insulator corona discharge using the DayCor® Superb UV imager in this paper. During the experiments, voltages are applied on a FXBW-35/70 insulator, and corona discharge was detected through the ultraviolet imager. The relationship between the detected photon number, the instrument gain and the distance are studied. Then through extracting the discharge facular area from UV image using Matlab package, the differences of photon number and facular area in quantifying the corona discharge intensity are compared and analyzed. Research shows that the photon number increases first and then decrease with the rise of UV gain. Differently, the facular area increases monotonically with the rise of gain. There will be no multi-valued problem when the facular area is used to quantify the discharge. Both the photon number and facular area decrease with the increase of detecting distance, but the fluctuation of the facular area-distance curve is smaller than the photon number — distance curve. Using the facular area to quantify the corona discharge can be more accurate. The study results of this paper provide references for better assessing the electric equipment corona discharge intensity by ultraviolet imager.