Corona Discharge Characteristics for Fittings of AC Transmission Line Under Rainy Conditions

Abstract

The corona discharge characteristic of the fittings is one of the key factors affecting the electromagnetic environment of the UHV transmission project. In the rain environment, the corona discharge characteristics of fittings are obvious. To study the influence of water drops on corona characteristics of fittings, the visible corona test, RIV test and audible noise measurement were carried out in Ultra-high Voltage Test Base in Wuhan under both dry and rainy conditions with the self-constructed water spray apparatus. The visible corona discharge characteristics were measured by an electromagnetic interference test receiver, a sound meter and a ultraviolet image apparatus. The test results show that compared with the dry condition test, the inception corona voltage of fittings is significantly reduced under rainy condition, and at most, the inception corona voltage is reduced to 36.6 % under dry condition. At the same voltage, compared with the dry condition test, the electromagnetic environment of fittings deteriorated seriously under the rainy condition, and the audible noise and radio interference level increased significantly. Under dry condition, the audible noise and radio interference levels suddenly increase significantly at the inception corona voltage; Under rainy condition, the level of audible noise and radio interference increases gradually with increasing voltage, and the growth rate does not appear obvious jump phenomenon.