To study potential distribution of 1 100 kV gas insulated switchgear after short arc ignition which leads totransient enclosure potential rise under lightning impulse and power frequency combined withstand voltage

eachcomponent of test loop will be equivalent to be centralized or distributed parameters for the research adopts the trans-mission line theory. Especially insulating flange should be considered to be series capacitor

so that the whole tran-sient model can be established.The computed result of the simulation model is compared with the test data to verifythe accuracy of the model establishment

and gain the distribution law of transient enclosure voltage in the test loopas well as choose the type of grounding line and grounding mode properly. Finally the research confirmed the superi-or performance of copper foil grounding to suppress amplitude and frequency of transient voltage.