The effect of temperature and humidity on corona inception voltage gradient of UHV DC transmission line

To research the effect of temperature and humidity on corona inception voltage gradient of UHV DC transmission line, a mini corona cage has been constructed and put in a manual environment room, which temperature and humidity can be controlled. At the same time, a corona inception voltage gradient measuring system by using vary methods such as current impulse method, acoustic method have been set up too. The corona inception voltage gradient of a copper line have been measured in a mini corona cage not only at different absolute humidity from 3 g/m³ to 12 g/m³ but also at different temperature from 0degC to 35degC. The relationship between corona inception voltage gradient and temperature and humidity have been achieved.