Electrical energy is one of the most important and almost inseparable needs of human life today. Every year there is always an increase in electricity demand due to an increase in people's lives, this increase must be accompanied by good and reliable electricity distribution services. In the operation of a network system, reliability distribution is the success rate of a system to carry out continuous distribution to customers. This study aims to analyze the reliability of the electric power distribution system at the Wates Substation in 2017. The parameters used to determine the reliability of this distribution system are SAIFI (System Average Interruption Frequency Index), SAIDI (System Average Interruption Duration Index), CAIDI (Costumer Average Interruption Duration Index), ASAI (Average Service Availability Index), and ASUI (Average In-dex Unavailability Service). Then compare the reliability index values that are in accordance with the standards used, namely the SPLN standard 68-2 1986, the IEEE standard 1366-2003 and the World Class Company (WCC) & World Class Service (WCS) standards. In this study also performed ENS (Energy Not Supplied) calculations to find out the amount of energy not channeled which is a loss for suppliers, namely PT. PLN. Based on the calculation and reliability index analysis that has been done, the results show that, based on the SPLN standard 68-2 1986, the SAIFI value for all feeders is said to be less reliable because it is larger than the standard, namely 3.2 times / customer / year. The SAIDI value for all feeders is categorized as reliable because it is smaller than the standard 21.9 hours / customer / year. Whereas based on the IEEE standards 1366-2003 and World Class Company (WCC) & World Class Service (WCS) standards the value of SAIFI and SAIDI for all feeders of the Wates Substation was declared less reliable. Losses that cannot be channeled based on ENS are 307,699 KVAh. To increase the value of reliability, repairs and maintenance are needed.