Q4: The single line diagram of an unloaded power system is shown in Fig. below. Reactances of the two sections of the transmission line are shown on the diagram. The generators and transformers are rated as follows: Generator 1: 20 MVA, 13.8 kV, X=0.2 pu Generator 2: 30 MVA, 18 kV, X = 0.2 pu Generator 3: 30 MVA, 20 kV, X«=0.2 pu Tị: 25 MVA, 220 Y:13.8 AkV, X = 10% T;: single-phase units, each rated 10 MVA, 127 Y:18 A kV, X = 10% T;: 35 MVA, 220 Y:22 Y kV, X= 10% a. Draw the impedance diagram with all reactances marked in per uint with letters to indicate points corresponding to the single line diagram. Choose a base of 50 MVA, 13.8 kV in the circuit of generator 1. b. Suppose that the system is unloaded and that the voltage throughout the system is I per unit on bases chosen in part a. If a three-phase short circuit occurs from bus C to ground, find the phasor value of the short circuit current (in amperes) if each generator is represented by its subtransient reactance. j 80 Q -머

Q4: The single line diagram of an unloaded power system is shown in Fig. below. Reactances of the two sections of the transmission line are shown on the diagram. The generators and transformers are rated as follows: Generator 1: 20 MVA, 13.8 kV, X=0.2 pu Generator 2: 30 MVA, 18 kV, X = 0.2 pu Generator 3: 30 MVA, 20 kV, X«=0.2 pu Tị: 25 MVA, 220 Y:13.8 AkV, X = 10% T;: single-phase units, each rated 10 MVA, 127 Y:18 A kV, X = 10% T;: 35 MVA, 220 Y:22 Y kV, X= 10% a. Draw the impedance diagram with all reactances marked in per uint with letters to indicate points corresponding to the single line diagram. Choose a base of 50 MVA, 13.8 kV in the circuit of generator 1. b. Suppose that the system is unloaded and that the voltage throughout the system is I per unit on bases chosen in part a. If a three-phase short circuit occurs from bus C to ground, find the phasor value of the short circuit current (in amperes) if each generator is represented by its subtransient reactance. j 80 Q -머

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter3: Power Transformers

Section: Chapter Questions

Problem 3.49P: Consider the single-Line diagram of a power system shown in Figure 3.42 with equipment ratings...

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Consider the single-Line diagram of a power system shown in Figure 3.42 with equipment ratings given: Generator G1: 50MVA,13.2kV,x=0.15p.u. Generator G2: 20MVA,13.8kV,x=0.15p.u. Three-phase -Y transformer T1: 80MVA,13.2/165YkV,X=0.1p.u. Three-phase Y- transformer T2: 40MVA,165Y/13.8kV,X=0.1p.u. Load: 40MVA,0.8PFlagging,operatingat150kV Choose a base of 100 MVA for the system and 132-kV base in the transmission-line circuit. Let the load be modeled as a parallel combination of resistance and inductance. Neglect transformer phase shifts. Draw a per-phase equivalent circuit of the system showing all impedances in per unit.
With the same transformer banks as in Problem 3.47, Figure 3.41 shows the oneline diagram of a generator, a step-up transformer bank, a transmission line, a stepown transformer bank, and an impedan load. The generator terminal voltage is 15 kV (line-to-line). (a) Draw the per-phase equivalent circuit, aounting for phase shifts for positive-sequence operation. (b) By choosing the line-to-neutral generator terminal voltage as the reference, determine the magnitudes of the generator current, transmiss ion-line current, load current, and line-to-line load voltage. Also, find the three-phase complex power delivered to the load.
PowerWorid Simulator case Problem 3_60 duplicates Example 3.13 except that a resistance term of 0.06 per unit has been added to the transformer and 0.05 per unit to the transmission line. Since the system is no longer lossless, a field showing the real power losses has also been added to the oneline. With the LTC tap fixed at 1.05, plot the real power losses as the phase shift angle is varied from 10 to +10 degrees. What value of phase shift minimizes the system losses?
Q4 / Equipment ratings for the four - bus power system shown in Figure are given as follows: TI 73 60 500 Generator GI: 500 MVA, 13.8 KV. X = X2 = 0.20. Xo = 0.10 per unit Generator G2: 750 MVA, 18 KV.X = X2 = 0.18, Xo = 0,09 per unit Generator G3: 1000 MVA, 20 kV, X = 0.17. Xz = 0.20.Xo = 0.09 per unit Transformer Ti: 500 MVA, 13.8 kV A / S00 kV Y. X = 0.12 per unit Transformer T2: 750 MVA, 18 LV A / 500 kV Y, X = 0.10 per unit Transformer T3: 1000 MVA, 20 kV A / 500 kV Y. X = 0.10 per unit each line: X = 50 ohms, X, = 150 ohms 77 The inductor connected to generator G3 neutral has a reactance of 0.028 pu. Draw the zero-, positive-, and negative - sequence reactance diagrams using a 1000 - MVA, 20 - KV base in the zone of generator G3
Given the two-machine system of Figure below, we select quite arbitrarily a base voltage of 161 kV for the transmission line and a base voltampere of 20 MVA. Find the pu impedances of all componenrs referred to these bases. The apparatus has ratings as follows: Generator: 15 MVA, 13.8 kV, x=0.15 pu Motor: 10 MVA, 13.2 kV, x=0.15 pu T1: 25 MVA, 13.2-161 kV, x=0.10 pu T2: 15 MVA, 13.8-161 kV, x=0.10 pu Load: 4 MVA at 0.8 pf lag
Draw an impedance diagram for the electric power system shown in the figure attached, showing all impedances in per unit on a 100-MVA base. Choose 20kV as the voltage base for generator. The three-phase power and line-line ratings are given in the figure attached.
The figure below shows the one-line diagram of a simple three-bus power system withgeneration at bus 1. The voltage at bus 1 is V1 = 1.0∠0°per unit. The scheduledloads on buses 2 and 3 are marked on the diagram. Line impedances are marked inper unit on a 100 MVA base.(a) Using Gauss-Seidel method and initial estimates of ?2(0) = 1.0 + ?0, ?3(0) = 1.0 + ?0, determine V2and V3. Perform two iterations.(b) If after several iterations the bus voltages converge to?2 = 0.90 − ?0.10 pu?3 = 0.95 − ?0.05 pudetermine the line flows and line losses and the slack bus real and reactive power.
Using NEC: What is the size of a generator feeder, with a 100A OCPD, single phase, 20KW, 120/240V, with terminals at 75°C?
b. Calculate the value of the short circuit current, the current provided by the generator, and the voltagesIn the generator node and in the load node, if a symmetric three -phase failure occurs in half ofthe line.
The annual load duration curve of a power supply system may be considered as straight line from 40 MW to 8 MW. The load factor of the system is ?
1. What are the applications for stripline and microstrip transmission lines? 2. Give 2 examples of characteristic impedance application for each stripline and microstrip transmission lines.
A single-line diagram of a four-bus system is shown in fiugre. Equipment ratings and per-unit reactances are given as follows.Machines 1 and 2: 100 MVA 20 kV; X1= X2 = 0.2; X0= 0.04 Xn= 0.05 Transformers T1 and T2: 100 MVA 20Y/345Y kV; X1 = X2 = X0 = 0.08. On a base of 100 MVA and 345 kV in the zone of the transmission line, the series reactances of the transmission line are X1 = X2 = 0.15 and X0=0.5 per unit. (a) Determine the bus impedance matrix for each of the three sequence networks. (b) Assume the system to be operating at nominal system voltage without prefault currents when a bolted single-line-toground fault occurs on phase A at bus 3. Compute the fault current, the current out of phase C of machine 2 during the fault, and the line-toground voltages at the terminals of machine 2 during the fault. Total detailed answer is needed. The figure is attached.