A three-dimensional electrostatic field model of the power distribution room and dry ice cleaning device is set up in order to analyze whether such phenomena as corona discharge or gas breakdown occurs in case of live operation of the dry ice cleaning device of the designed 10 kV power distribution room.The electric field and potential distribution of different material and shape of the nozzle as well as the dry ice cleaning device performing cleaning operation with different cleaning distances in 10 kV power distribution room are obtained.The influence of the material and shape of the nozzle as well as the cleaning distance on the maximum field strength and the highest potential of the nozzle surface is analyzed and test verification is performed.It is known by the simulation result that at the voltage at 10 kV

the maximum field strength at such four conditions as straight nozzle of metal material

straight nozzle of insulating material

right-angle nozzle of metal material and right angle nozzle of insulating material is 0.22 kV/cm and is less than the critical field strength.Therefore

neither corona discharge nor gas breakdown phenomena occurs with the cleaning distance d within 10～20 cm.The test result is identical to that of simulation

which provides basis for the shape of nozzle and its material selection.