PT Petrokimia Gresik is the largest and most complete fertilizer producer in Indonesia which has a huge production target. Therefore, all matters relating to the achievement of targets need to be managed properly. No exception with the availability of electrical energy. The need for enormous electrical energy and the continuity of energy distribution. The need for enormous electrical energy and the continuity of the distribution of energy greatly affects the performance of the company, especially the production process. Therefore, protection of electric power system becomes vital in maintaining the continuity of energy distribution and security against fault. The overcurrent relay is a part of the protection apparatus, where protection coordination is necessary to reduce adverse effects when there is over current fl owing. Some quantities to be considered in the current relay setting are the nominal current of the equipment and the maximum short circuit current on the equipment. While the parameters that need to be included in the current relay settings are among other types of curves selected, pickup currents, time multiple settings, instantaneous and delay. All those parameters will affect the trip characteristics of the circuit breaker. This study obtained the value of field settings and manual calculations and how the performance of coordination through simulation using ETAP software 12.6. The result of this research is finding that on setting of field relay, AUT2 and AT2 relay mounted on primary and secondary part of transformer have an intersect coordination of protection curves and there can be failure of coordination of protection. After resetting with manual calculation there is no intersect coordination of protection curves that indicates the coordination of protection is going well and there will be no coordination failure at any level of fault.