Pressure

temperature

and humidity are three environmental factors which effect corona discharge detection of power transmission equipment. In order to study the relationship between them

taking robust-plate gap as research object

by means of ultraviolet（UV） imaging instrument of Coro CAM504 in artificial simulation climate tank

we researched the variation characteristics of corona inception voltage and the size of discharge ionization region under different environmental factors and robust-plate gap. The accuracy of the results was verified through discharge test at plain and plateau area

respectively. The results show that

pressure and absolute humidity have significant effects on corona inception voltage while temperature has little effect on it. Corona inception voltage increases with the increases of pressure and absolute humidity

the relationship between them is approximate power function. At the same time

corona inception voltage slightly increases when the gap of robust-plate increases. The size of discharge ionization region reduces with the increasing of pressure and absolute humidity

the relationship between spot area and pressure

absolute humidity is approximate power function.