Electrical energy is a vital energy source for a country's survival. Over time, external issues arise which can happen in electrical energy management. An internal issue that occurs is lightning interference that can trigger overvoltage on a high voltage system like a Transformator. Arrester is one of safety equipment for substation Transformator. The system operates by restricting the overvoltage surges coming next to the ground. The arrester mounted in 150 kV Godean substation with the brand OHIO BRASS has a spark voltage of 650 kV and the Transformator installed in the substation has a voltage of 715 kV BIL. In this research, according to the field information, the distance between arresters and transformator was calculated and a distance of 9.75 meters was achieved. While at the 150 kV Godean Substation the installation range is 3 meters. Both values are still below the IEC (1958) and SPLN (1978: 4) peak values with a value of 28.5 meters. In the 150 kV Godean Substation, however, the range of 3 meters is more efficient due to the arresters are in a place nearer to the transformator so that the arresters can better safeguard the voltage. After that, simulations and analyzes are performed using ATP software (Alternative Transient Program) from the distance in the field and calculations. It was discovered from the outcomes of the assessment that the positioning of arresters at a distance of 3 meters could cut the voltage better.