Detection of point-plane corona discharges using the solar blind photosensitive tube

Contact sensors have been used widely to detect partial discharges. However, the surrounding on-site electromagnetic interferences decrease the sensitivity and signal-to-noise ratio of the detecting device. The light is observed when discharge occurs. Therefore the phenomenon of the discharge can be detected through optical sensors. To avoid the affect of sunlight on the results, most optical sensors need to equip with filters or be installed in opaque equipments. This paper presents one type of solar blind UV tube which has a narrow spectral sensitivity and is insensitive to visible light. The UV tube consists of a simple system and is easy to use for detecting the partial discharge. A series of experiments were conducted to investigate characterizing the strength of the partial discharges by several parameters; moreover, the efficiency of the UV tube was also compared with that of other approaches. Through this study, the frequency of UV pulses was selected as the characterizing parameter. Moreover, the experimental results suggest that the UV tube has a higher sensitivity compared with the current sensing device.