Research of Discharge Characteristics of CO2 Gas in Small Distance

In order to find a new kind of insulates gas to substitute for SF6 gas, a discharge device has been development with shifter electrodes and adjusts distances automatic. Uniform electric field, non-uniform electric field had been achieved in this discharge device. The power-frequency voltage-withstand test of CO2 gas has been taken in these three kinds of electric field. In this test, data of breakdown voltage were obtained under different pressure and distances of electrodes with 99.99% purity of CO2. It can be seem from these data that the value of breakdown voltage is positive correlation to pressure and distances of electrodes. Whats more? For uniform electric field, the dielectric strength meet the requirement of power-frequency voltage-withstand of 110kV gas insulation device when the distance of test electrodes no less than 30mm. For non-uniform electric field, the dielectric strength of gas insulation of CO2 gas has little difference until the pressure increased to 0.5MPa. According to the data of power-frequency voltage-withstand test it can be conclude that the 0.5MPa is a key indicator to improve the insulating properties.