@thesis{thesis, author={Pratiwi Rahmawati Hardian and Suwarno Suwarno}, title ={ANALISIS PENYETELAN RELE DIFERENSIAL PADA TRANSFORMATOR GENERATOR UNIT 5 PT. INDONESIA POWER UNIT PEMBANGKITAN SURALAYA}, year={2018}, url={http://156.67.221.169/771/}, abstract={Power plant is a unit system used to produce electrical energy which is then delivered to the transmission network and distributed to consumers. Steam power plant at PT. Indonesia Power UP Suralaya which has a total capacity of 3400 MW with 7 unit of the plant which supply electricity to Java and Bali, that should be able to work with the maximum and reliable for distributed electricity supply to consumers. Power plant main equipment is generator transformer, which used to transform the low voltage into high voltage. As the main safety and to ensure the reliability, added relay protection on the generator transformer. Protective relay is a device used to detect fault, either internal or external. The relay used in generator and transformer unit 5 is differential relay. Differential relay is a safety relay used to detect the internal fault in the power transformer that it works very fast and selective. Pickup current in this differential relay is 1,5 A, from testing performance pick up current set in 1,48 A. CT that they are using are class 5P20 with composite error 1,3%. From the calculation the result for 3 phase short circuit 7,7375 A which mean when there are fault current bigger than the current setting the relay will be pickup, also the relay doesn?t pickup in interfal fault happen.} }