Related InterviewSolutions

• A 30 MVA, 3-phase, 50 Hz, 13.8 kV, star-connected synchronous generator has positive, negative and zero sequence reactances, 15%, 15% and 5% respectively. A reactance (Xn) is connected between the neutral of the generator and ground. A double line to ground fault takes place involving phase 'b' and 'c' with a fault impendance of j0.1 p.u.. The value of xn(in p.u.) that will limit the positive sequence generator current to 4270 A is 1.07
• Consider the network shown in the figure. The bus numbers and impedances are marked. A 3−ϕ short circuit fault occurs at bus 2. The subtransient current of the fault in per unit is ___.0.33
• A 3-phase, 50 Hz, synchronous generator has rating 200 MVA, The Kinetic energy of the machine at synchronous speed is 800 MJ. The machine is running steadily at synchronous speed and delivering 50 MW power at power angle of 10 electrical degrees. If the load is suddenly removed, assuming the acceleration is constant for 8 cycles, the value of power angle after 4 cycles is ___________electrical degrees. 11.81
• The incremental cost characteristic of two plant systems are IC1=1.0P1+85Rs/MWhr IC2=1.2P2+72Rs/MWhrwhere P1 and P2 are in MW. The loss coefficient matrix in MW is (0.012−0.001−0.0010.04] the optimum scheduling for λ=150Rs/MWhr will be
• Two generating units rated 300 MW and 400 MW have governor speed regulation of 6% and 4% respectively from no load to full load. Both the generating units are operating in parallel to share a load of 600 MW. Assuming free governor action the load shared by the larger unit is 400
• A balanced delta connected load is fed from a 3-ϕ supply. For which, the phase c is open circuited. The currents in the lines are shown. The magnitude of Ib1 is______A.5.77
• A 50 Hz generator is delivering 60% of power that it is capable of delivering through a transmission line to an infinite bus. A fault occurs that increases the reactance between the generator and the infinite bus to 400% of the value before the fault. When fault is isolated, the maximum power that can be delivered is 75% of the original maximum value. For this condition critical clearing angle (in degres) is
• For the power system shown below, specification of the components are as follows :G1=11 kV,40 MVA,X=5%T1=11kV33kV,80 MVA, X=10%: T2=33kV11kV,80 MVA, X=10%M1=11 kV, 40 MVA X=5%Line reactance X=50 ΩThe reactance diagram on base MVA=80 MVA is
• In a system, there are two generators operating in parallel. One generator, of rating 250 MVA, has an inertia constant of 6 MJ/MVA while the other generator of 150 MVA has an inertia constant of 4 MJ/MVA. The inertia constant for the combined system on 100 MVA common base is MJ/MVA.21
• A transmission line has 0.1 pu impedance on a base of 132 kV, 100 MVA. The pu impedance on a base of 220 kV, 50 MVA is ____pu.0.018