Improving reliability on MV distribution line in the system connected to distributed generator in South Sumatra, Indonesia, a case study

PT. PLN (Persero) Wilayah Sumatera Selatan, Jambi, dan Bengkulu, is one of the Service Region that provides electricity services and ensures the reliability and continuity and quality of delivery electricity to all customers in the region. In order to satisfy this obligation and fuel mix, PT. PLN (Persero) WS2JB purchases a part of the energy need from the Small Scale IPP connected to 20 kV Medium voltage line connected from the IPP direct to customer or via 20 Substation busbar. During the operation, the feeder supplied by the IPP experienced relatively low reliability affected by the overload, underload, or the misoperated relay. This paper discusses the problem that was investigated by Operational Performance Improvement (OPI) approach and shares the solution for the problem. It was found that 3 (three) major cause, namely, protection Scheme, Syncronization placement, and setting the capability curve of the machine was profound. To alleviate the Problem, the solution was conducted by resetting the protection scheme, rearranging the syncronization device in the busbar configuration and modifying the setting of relay. The additional corrective measure of maintaining the line properly is also discussed. After conducting the afromentioned modification the reliability increase significantly. The rate of feeder failure is down by 50 %.