UHV AC corona loss measurement and analysis under rain

Transmission line corona loss research is one of the critical technologies of 1000 kV UHV transmission and transformation engineering. Transmission line corona loss relates with many factors of climate, and rainfall rate effects corona loss distinctly very much. By means of UHV AC single circuit test line corona loss monitoring and UHV corona cage conductor corona loss measurement, this paper researched the effect of rainfall rates to UHV AC single circuit transmission line's corona loss. This paper applied corona loss monitoring system to monitor corona loss of UHV single circuit test line, and obtained corona loss monitoring data in light rain, moderate rain, and heavy rain conditions. Analyze corona loss test results. Corona loss value in light rain, moderate rain, and heavy rain conditions are obtained. The results show that, rain has an obvious influence on corona loss of the line, at the beginning of raining, corona loss increases quickly, after rain, corona loss decreases with drying of the conductor. Decay time is related with surface field strength, wind speed, air humidity, temperature and other factors. When rainfall rate is low, corona loss increases fast with the increase of the rainfall rate. With the increase of the rainfall rate, corona loss grows slowly. When rainfall rate increases to some level, corona loss stop growing.