Problems
8.1 Consider the single-phase radial power system shown in Figure 8.22. The leakage impedance
of the transformer is (0.0 + j0.02) pu and the feeder impedance on the same base is (0.01 +
j0.06) pu. The transformer and the system base power is 100 kVA. The transformer voltage
ratio is 11/3.3 kV. Time–overcurrent protection is to be provided by the relays Rab and Rbc.
Using the relays with characteristics shown in Figure 4.5, determine the CT ratios, pickup
values and the time dial settings for the two relays. You may assume that no other coordination
considerations apply to this problem