Abstract:Along with the deepening of the construction of smart substation, there are a growing number of electronic equipments in substation, due to the existence of a large number of high voltage and high current equipment, it is very complicated electromagnetic environment of the substation, easily on these electronic devices cause interference, affecting its normal operation.In the actual operation, it is found that the switching action of the substation will result in a relatively large impact on the power grid, the formation of high frequency electromagnetic waves, with strong interference ability, a serious impact on the power system reliability. Through moments of action of voltage and current distribution calculation of substation switch, for the transient electromagnetic interference analysis, discussed the influence of the system, and puts forward the corresponding measures to solve transient disturbance of the door.