For each of the following power systems, do following: 1. Compute the Y_bus in rectangular and polar forms 2. Set up the power flow problem as follows (see the sample example) Identify the type of each bus State the unknown and known variables at each bus Write the power flow equations

Q4 (a) (b) A 4-bus power system, as shown in Figure Q4a, of which the parameters are given in Table Q4a; the p.u. value of every component is given based on its own base values (rating). i) Draw an impedance diagram of the network, showing all impedances in p.u., on 1000 MVA and 20 kV base values in the Generator G3 zone. A three-phase short circuit occurs at busbar 3 through a rearance of j0.12 p.u., where the pre-fault voltage is 525 kV and the pre-fault current is neglected. Calculate the short circuit current in p.u. using Thevenin's Theorem. Describe the data required for each component of a typical power network when analysing faults, and the reasons for needing each item of data. T, bus 1 ∞to ΔΥ G₁ G₂ G3 T₁ T₂ Тз Transmission line: 150 Ω bus 4 T₂ bus 2 150 Ω 150 Ω G₂ YE bus 3 T₂ 머( YEA Figure 04a 500 MVA, 13.8 kV, XG1= 0.20 p.u. 750 MVA, 18 kV, XG2 = 0.18 p.u. 1000 MVA, 20 kV, XG3 = 0.17 p.u. 500MVA, 13.8 (A) /500 kV, XT1 = 0.12 p.u. 750 MVA, 18 (A) /500 kV, XT2 = 0.10 p.u. 1000…