The use of SF

6

mixed gas in gas insulated electrical equipment can prevent the liquefaction of SF

6

gas

which is mainly used in extremely cold conditions. In order to obtain the law that the discharge characteristics of SF

6

/CF

4

gas mixture are affected by temperature when there are tip defects in the equipment

the needle plate electrode is used to simulate the tip defects

and the power frequency discharge tests of SF

6

/CF

4

gas mixture at different pressures and temperatures are carried out. It is found that the breakdown voltage of SF

6

/CF

4

gas mixture shows an increase - decrease - increase

namely hump curve

with the increase of pressure 0.1-0.7 MPa and in the temperature range of -50-20 ℃. With the decrease of temperature

breakdown voltage at the hump peak decreases with the decrease of temperature

while the breakdown voltage at non-hump peak basically remains unchanged. By analyzing the effect of temperature on space charge

the mechanism that the breakdown voltage of SF

6

/CF

4

gas mixture is affected by temperature at different pressure is explained.