Open PowerWorld Simulator case Problem 6_49. This case is identical to Example 6.9 except that the transformer between buses 1 and 5 is now a tap-changing transformer with a tap range between 0.9 and 1.1 and a tap step size of 0.00625 . The tap is on the high side of the transformer. As the tap is varied between 0.975 and 1.1, show the variation in the reactive power output of generator \(1, \mathrm{~V}_{5}, \mathrm{~V}_{2}\), and the total real power losses.

Data From Example 6.9:-

FIGURE 6.2 Single-line diagram for Example 6.9 Figure 6.2 shows a single-line diagram of a five-bus power system. Input data are given in Tables 6.1, 6.2, and 6.3. As shown in Table 6.1, bus 1, to which a generator is connected, is the swing bus. Bus 3, to which a generator and a load are connected, is a voltage-controlled bus. Buses 2, 4, and 5 are load buses. Note that the loads at buses 2 and 3 are inductive since Q = -QL2 = -2.8 and -QL3 = -0.4 are negative. For each bus k, determine which of the variables Vk, k, Pk, and Q are input data and which are unknowns. Also, compute the elements of the sec- ond row of Ybus. SOLUTION The input data and unknowns are listed in Table 6.4. For bus 1, the swing bus, Pi and Qi are unknowns. For bus 3, a voltage-controlled bus, 400 MVA 5 4 T1 T2 800 MVA 345/15 kV B1 B51 Line 3 B41 B3 345 kV 50 mi B42 3 520 MW 800 MVA 15 kV 15 kV B52 400 MVA 15/345 kV 345 kV 100 mi B21 Line 2 Line 1 200 mi 345 kV 40 Mvar 80 MW 822 2 280 Mvar, 800 MW