a. Determine the equivalent (Thevenin) circuit at the fault point (FX) b. Determine the operation time of the four overcurrent elements at the 115 kV side of the transformer, for

a phase a-to-ground fault at the point indicated on the13.8kV line, very close to the bus. These relays are connected to CT's with CTR=200/5. The phase relays have I pick-up=5 A, TD=2; and the ground element has Ipick-up=1 A and TD=3. All the relays have U.S. very inverse curve.(Assume transformer is Dyn1)