Question 2 Assume the 11.5 kV system shown in Fig. 2 is open a) Show the three phase connections for transformer differential relays to protect this transformer. b) Select suitable current transformer ratios for this transformer differential application. CTS with ratios in steps of 50/5 up to 2500/5 should be used. c) If relays with a variable-percentage characteristic are used and the available current taps are: 5.0-5.0, 5.0-5.5, 5.0-6.0, 5.0-6.6, 5.0-7.3, 5.0-8.0, 5.0-9.0, and 5.0-10.0 A, select proper relay taps and calculate the percent mismatch. d) How much current can flow in the differential relay(s) for an internal solid phase-a-to- ground fault on the 11.5 kV terminals? 3. 30 MVA 69 kV 10% mo p 30 MVA 69/11.5 kV 90 5/11 Fig. 2