Smart GIS has been popularized and applied in power systems due to its compact structure and low cost

which meets the requirements of operation and maintenance units. However

the low insulation evaluation index in the early stage causes this type of equipment to have a high fault rate. In this paper

the gap breakdown on the shield cover of smart GIS with a high faults is taken as an example to study the operating reliability of this type of equipment and

on the basis of study result

propose improvement measures. First

the fault is analyzed through the electric field simulation

fast transient over voltage calculation and insulation margin check and the main reason for the fault is given. Then

such three improvement measures as structure optimization

control of foreign matter in the enclosure and UHF insulation monitoring of the smart GIS are given on the basis of electric field simulation

flow field simulation and UHF partial discharge characteristics in the withstand voltage test so to avoid recurrence of the same type of fault. Finally

the effectiveness of the measures proposed in this paper is verified through AC withstand voltage test and the insulation margin check at 1.1 times lightning impulse in the condition of artificial embedded foreign matters.