Electrical energy is a vital energy for survival in a country. In the course of time, problems arise that can be experienced in the management of electrical energy. One external problem that arises is that interference can cause interference with high voltage systems such as Transformers. One function for Transformers in the Substation is Arrester. The work system is by transferring further frequencies from being channeled to the ground. Arrester installed at 150 kV substation Purworejo with OHIO BRASS brand has a spark voltage of 650 kV, while the transformer installed at the substation has a BIL voltage of 715 kV. At this time the distance between arresters and transformers was measured according to the data in the field and obtained a distance of 9.75 meters. While the distance in Purworejo 150 kV Substation was 8 meters. Both values are still below the maximum values of the IEC standard (1958) and SPLN (1978: 4) with a value of 28.5 meters. However, the value of 8 meters in the 150 kV substation in Purworejo is more useful because the arrester is in a position closer to the transformer, the arrester with more than a better voltage. Then from the distance in the field and calculations are carried out simulation and analysis using ATP (Alternative Transient Program) software. The results obtained from the arrangement of arresters with a distance of 8 meters with a better voltage.