Discuss the reasons that make the load flow problem non-linear.

By comparing the principle of operation of a "three" phase generation system with a single-phase system, state what are the bendfits of three phase systems? In your own words, define the "skin effect" in transmission lines and discuss how can it be minimised? Name three advantages of AC transmission in comparison to DC transmission. What are the units of active, reactive and apparent power? The current in a single-phase motor lags 50° behind the voltage. What is the power factor of the motor?

What is a load flow analysis, and why is it important in power system engineering?

A network consisting of a set of generator and load buses is to be modeled with a DC power flow, for the sake of conducting a contingency analysis. The initial flows calculated with the DC power flow give the following information: f°2-4 = - 65.3 MW and fº4-5 = 13.6 MW. The following values of LODF and PTDF factors are given: PTDF54,2-4 = -0.2609, LODF2-4,4-5 = -0.6087. Calculate the contingency flow on line 2-4 due to outage of line 4-5. Select one: O a. -75.5MW O b. None of these O c. -68.85MW O d. -73.58MW O e. 75.5MW O f. -61.75MW

Q2. A de shunt generator has a full load curent of 50A at 200V. The stray losses are 500w and Ra 502. If the full load efficiency is 80%, find ) Ra (ii) Load current corresponding to maximum efficiency (i) Draw the variation of load current with efficiency (estimate)

consider the ID as 12345678

To qualify system stability, we use: a. Routh criterion b. Phase margin c. Gain and phase margin d. Gain margin

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…

Sketch and label the main working components of a wind turbine. Describe the functionality of each of the parts.  List various foundation structure for offshore wind turbines and describe their advantages and disadvantages and relate their configuration to appropriate water depth.

Q2) The bus-bar (A) and (B) are linked by a bus-bar reactor of 1000 KVA with 10% reactance on bus-bar (A). The system has 2 generators each one of 5000 KVA with 5 % reactance, and on bus-bar (B) two motors each one of 5000 KVA with 12% reactance. Find the steady state apparent power (MVA) given to the symmetrical short circuit occurred on bus-bar (B) in the circuit shown below. Ма Mi B Gi A G₂ Xr m