The analysis of grounding system at 150 kv Semanu Substation was conducted with the aim to find out whether humans who are in the area of the substation are safe against touch voltage and step voltage when there is a disruption in the electric power distribution system. Analysis of grounding systems is carried out by knowing the condition of the grounding system and the type of soil that exists in that location. Then make the calculations and compare that calcuulation with the standards issued by the IEEE (Institute of Electrical and Electronics Engineers) number 80 which discusses procedures for the security of grounding AC current substations. In this study the results of step voltage for 50 kg is 712.4 volts and for 70 kg is 962 volts, while the actual step voltage was 68.04 volts. Then the touch voltage for 50 kg is 280.85 volts and for 70 kg is 379.25 volts, while the actual touch voltage is 33.1 volts. Based on these standard a safe grounding system is when the actual touch/ step voltage is smaller than the touch/ step voltage allowed. So that it can be concluded that the grounding system at 150 kv Semanu Substation is safe based on IEEE std. 80 Guide for Safety in AC Grounding Substation standard