It will corrode the parts and decline electrical equipment insulation property after condensation formed in-side switchgear

which could initiate insulation flashover of equipment. In connection with the phenomenon

a con-densation observation system of the switchgear is set up in artificial climate chamber

and the condensation forma-tion time under different temperature and relative humidity in the interior switchgear is recorded. The results showthat

the condensation formation time is determined by temperature and relative humidity

the higher the tempera-ture

and the greater the relative humidity

the shorter the time of condensation formation. By analyzing the relation-ship between humidity ratio and temperature with relative humidity

it is concluded that humidity ratio increaseswith the temperature and relative humidity

which explains the connection between the condensation formation timeand temperature with relative humidity in theory

and proves the accuracy of the test results.