Analisis Setting Over Current Relay dan Ground Fault Relay Pada Sisi Incoming Travo 60 MVA dan OutgoingFeeder

A Feeder in the medium-voltage of 20 kV system is used for the electricity distribution from substation to the consumer. But in fact, at the network distbution there are a many kinds of disturbances, both of phasa to phasa and phasa to ground. So it is very necessary to have a security devices that can be responded quicly, flexibly and reliably. Security devices which used to overcome the problem of over-current disturbance are OCR (Over-Current Relay) and GFR (Ground-Fault Relay). In installating of these relay, it is also set the working time setting, in order to have a coordination to the other relay. From the results of this study obtained that the largest current disturbance of 3Ø, 2Ø and 1Ø located at the network base (1% of channel) is (R,S,T= 6.471A, 3.235A and 286A), while the smallest disturbance current located at the end of the network (100% of channel) is (R,S,T= 400A, 200A and 149A). From this study also found that working time of OCR on the side of outgoing feeder was faster than incoming, the working time of outgoing relay was 0,3 second, then in the incoming side is 0,7 second for the (1% network length). So it can be concluded that the more near distance of disturbance, then the value of the disturbance will be great, and if the greater current of the disturbances happened then working time of relay will be quickl