A UV imager is a high-voltage electrical device. Corona, flashover or arcing often occurs due to design, manufacture, installation, maintenance, etc. During discharge, the electrons in the air continuously gain and release energy, and when the electrons release energy (ie discharge), they emit ultraviolet radiation. Its count value is affected by various factors such as detection distance, atmospheric humidity, temperature, atmospheric pressure, altitude, and instrument gain.

1. The effect of distance

The detection technology distance has a significant impact on the detection and analysis results. When the detection working distance can be increased, its field of view will decrease, and the sensitivity will decrease accordingly. 

2. Influence of humidity and dirt

The results show that the corona electric field strength decreases with the increase of humidity. Due to the increase of humidity, the electrical conductivity of the insulator surface increases, and the number of discharge pulses of the insulator string increases. However, it was found that the higher the atmospheric humidity, the more UV light was absorbed, which would reduce the detection effect of UV light. It can be seen that the influencing factors of humidity are complex. Whether the increase in humidity is beneficial to UV detection still needs to be analyzed and judged.

3. Influence of air pressure and temperature

When air pressure decreases or temperature increases, air density decreases and the average distance between air molecules increases. Under the action of the electric field, due to the increase of the free path, the energy obtained in the electric field increases, which makes the air easily ionized, thereby reducing the strength of the corona-inducing electric field. Conversely, if the air pressure increases or the temperature decreases, the strength of the corona electric field increases.

4. Affected by altitude

As the air pressure decreases, the rise increases and the initial corona voltage decreases. When the altitude increased by 2000m, the initial corona voltage decreased by 30%.

HZi800 Handheld UV Imager