eversvd,+4 (6)

The breakdown of electrical energy can be caused by the unwanted failures that occur in the electric power system, especially in the distribution system, and have an impact on service continuity which can be a permanent failure, temporary failure, three phase short circuit failure, double phase short circuit failure, and blackout. To anticipate this, a study needs to be done to analyze and find out how well the distribution system reliability index. Determination of the analysis was done by the method of data retrieval related to the analysis variable. Besides, in determining the results of the analysis, calculations using System Average Interruption Frequency Index (SAIFI), Customer Interruption Frequency Index (CAIFI), System Average Interruption Duration Index (SAIDI) and Customer Average Interruption Duration Index (CAIDI) analyses were performed. Based on the reliability of the distribution network, the SAIFI and CAIDI maximum threshold value setup by PT. PLN (The National Electricity Company) at the Semangga substation each worth 3.00 failures/customer.year and 3.00 failures/customer while SAIDI and CAIDI each worth value of 3.40 hours/customer.year and 3.40 hours/customer.failure. All feeders installed at Semangga switch substation in realization gives reliability indices smaller than the target that has been set, it is mean that 20 kV medium voltage air line distribution system at Semangga switch substation still reliable and the duration of the failure for each feeder was an average of 3 minutes of each failure and the number of failures every month was an average of 15 times of each feeder.