Influence of ambient humidity on UV imaging detection of polluted plate model discharge

Ultraviolet (UV) imaging technology is now widely used in the corona discharge detection of high voltage power transmission and transformation equipment as it is much more convenient and easier to be used than other detection methods nowadays. Insulators are broadly used in today's power transmission lines. This paper mainly studies the influence ambient humidity exerts on the UV imaging detection of polluted plate model discharge. Plate model is used to simulate a RTV-coated insulator surface. The RTV-coated plate model surface is artificially polluted and set in an artificial fog chamber. The gain of the ultraviolet imager, and the distance between the ultraviolet imager and the plate model are also taken into consideration. The photon number of discharge was measured by an ultraviolet imager and the leakage current at the corresponding discharge intensity was recorded. The curves of applied voltage, ambient humidity, leakage current and photon numbers of the ultraviolet imager were drawn respectively. The data and curves were analyzed and conclusions could be drawn: The effect of ambient humidity on the discharge of contaminated RTV-coated plate model is not static, it will change from weakened to enhanced; a relatively high ambient humidity would increase the discharge and reduce the ultraviolet signal caught by UV imager.