Abstract: The simulation model of a new 230 kV GIS substation in Ecuador was established by EMTP-RV electromagnetic transient software.Using the new model,the lightning overvoltage levels of the main equipment in the substation was calculated under different lightning intrusion,different tower and substation operation mode,and the insulation coordination of each equipment is checked.The results showed that the closer the lightning intrusion point is to the substation,the higher the overvoltage of lightning intrusion wave is.Generally,the overvoltage of lightning intrusion wave was the highest in the operation of single transformer,double busbar and double-circuit transmission line.Under different lightning locations and operation modes,the lightning overvoltage on the main equipment of the substation did not exceed its lightning withstand voltage level,and has a certain insulation coordination fit margin,which meets the requirements of safe operation.