@thesis{thesis,
		author={Sinaga  Rikardo Mangasi and Widyastuti  Christine},
		title ={Studi Kerja Rele Diferensial dan Rele Arus Lebih Trafo Tenaga TD-2 Terhadap Gangguan Hubung Singkat Di Busbar 20 kV GI Pematangsiantar},
		year={2017},
		url={http://156.67.221.169/862/},
		abstract={Power transformers is a vital tool in its function to supply power to the load center . In the power transformers can?t be avoided presence disruption. One of the disturbances is short circuit immediately addressed. Therefore, to overcome the interference necessary in order not to cause damage protection system that meets the requirements of sensitivity, reliability, selectivity, and speed, all of which depend on the correct setting of protection equipment. Protective equipment which is used for power tansformator is differential relays and overcurrent relays instructed Circuit Breaker (CB) function to open the contacts, so that disturbed power transformers can be separated from the system. Analysis from result test of Over Current Relay get is tms 0,27 on 150 kv with 0,39 on 20 kv and from the analysis calculation then obtained tms 0,614 on 150 kv with 0,1799 on 20 kv. Based on an analysis, setting relay over current are installed was correct and reliable for external fault transformator. And from analysis has performed with rele differential found differential relay found sensitive to internal fault transformator.}
		}