Solar Blind Ultraviolet Band
Ultraviolet band is in the range of 10nm to 400nm. When sunlight passes through the atmosphere, it cannot reach the earth's surface and form a blind area since the ozone layer has a strong absorption of ultraviolet from 240nm to 280nm. Therefore, the solar blind ultraviolet camera can be full-time used and has high reliability, low rate of false positives, and the advantages of strong anti-interference ability due to its elimination of the influence of the sun and other spectrum.
Principle of Corona Discharge Ultraviolet Imaging Detection
When the high voltage equipment electric discharges, the surrounding air will be ionized. During the ionization process, the electrons in the air molecules keep getting energy from the electric field. When electrons return from the excited state orbital to the original stable electron energy orbital, it releases energy in the form of corona, flash-over or spark discharge accompanied by ultraviolet radiation. Ultraviolet camera is using this principle to detect the ultraviolet signal during the process of high voltage electrical equipment discharge and display the processed real-time signal on the screen in order to diagnose discharge position and intensity and providing more reliable basis for evaluation of equipment running status.
The Difference between Ultraviolet Camera and Other Detection Methods
At present, the detection methods of corona discharge mainly include ultrasonic detection, infrared thermal imaging detection and ultraviolet image detection. The method of ultrasonic detection is to analyze and judge discharge mainly based on ultrasonic signals generated by partial discharge. This method is not affected by the strong electromagnetic environment in the substation, but the sensitivity of this method is low which means it can be disturbed by outdoors noises seriously. As a result, it can only detect a strong partial discharge and mechanical vibration. The most obvious feature of the infrared thermal imaging detection can conduct regional temperature measurement. The device temperature in one area will be presented in the form of images on the screen which can help you find temperature anomaly quickly. But it can only check out temperature anomaly until the defect or hazard development to a certain extent. Ultraviolet detection technology has high reliability, low rate of false positives, and the advantages of strong anti-interference ability owing to its elimination of the influence of the sun and other spectrum which can be used to find hidden danger of high voltage equipment as early as possible.
The Application of UV Camera
1.The wire cable injury detection, broken strands, burr, loose;
2.The insulator of corrosion, aging, cracking, zero or low value insulator failure;
3.The strapping is missing or improperly installed;
4.The lightning arrester failure, capacitor fault;
5.The casing filth and loose parts;
6.The preventive maintenance for converting station;
7.The examiner and repair for the high voltage electrical of railway, petroleum, mineral, and so on.