Lights Fuse Heater 600 DC Volts Line switch Fuse Fuse Main switch Circuit Breakers Fuse Transformer Fuse Fuse Relays Buzzers Governor Compressor (GE CP27) Line Breaker Meter Hood Switch Controller 1 Controller 1 Circuit Breakers Motor 1 Motor 2 Fuse Fuse Air Tank (2) Fuse Motor 3 Motor 4 Brake Cylinder

Lights Fuse Heater 600 DC Volts Line switch Fuse Fuse Main switch Circuit Breakers Fuse Transformer Fuse Fuse Relays Buzzers Governor Compressor (GE CP27) Line Breaker Meter Hood Switch Controller 1 Controller 1 Circuit Breakers Motor 1 Motor 2 Fuse Fuse Air Tank (2) Fuse Motor 3 Motor 4 Brake Cylinder

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

Chapter7: Symmetrical Faults

Section: Chapter Questions

Problem 7.21MCQ

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Similar questions

A single line diagram of a power system is shown in Figure Q2.1. The neutrals for the generators and transformers are solidly grounded. The motor neutral is grounded through reactance ?? = 0.05 per unit on the motor base. i）Calculate the phase currents in kA following a three-phase fault at busbar 2. ii) Calculate the phase currents in kA when a phase-alpha-to-ground fault occurs at busbar 2.
Three single-phase two-winding transformers, each rated 3kVA,220/110volts,60Hz, with a 0.10 per-unit leakage reactance, are connected as a three-phase extended autotransformer bank, as shown in Figure 3.36(c). The low-voltage winding has a 110 volt rating. (a) Draw the positive-sequence phasor diagram and show that the high-voltage winding has a 479.5 volt rating. (b) A three-phase load connected to the low-voltage terminals absorbs 6 kW at 110 volts and at 0.8 power factor lagging. Draw the per-unit impedance diagram and calculate the voltage and current at the high-voltage terminals. Assume positive-sequence operation.
The direct electrical connection of the windings allows transient over voltages to pass through the auto transfonner more easily, and that is an important disadvantage of the autotransformer. (a) True (b) False
solve with explanation.
Q2\ Two generators G1 & G2 are rated 15 MVA, 11 kV and 10 MVA, 11 kV respectively. The generators are connected to a transformer as shown in the following figure. Find the sub- transient current in each generator when a three-phase fault occurs on the high voltage side of the transformer. A/Y 15 MVA, 11 kV, X"gl=j0.10 pu G2 15 MVA, 11/66 kV, Xr-j0.06 pu 10 MVA, 11 kV, X"g2-j0.10 pu
Voltage unbalance is the unbalance that occurs when the voltages at different motor terminals are not equal. This is a big problem for power companies generating, and other facilities using three phase power. If left in this condition this can cause transformer and motor windings to prematurely burn open. Using a DMM you are troubleshooting a 480 volt, 3 phase power feeding a fused disconnect connected to a 3 phase, 1 H.P. motor. Your findings are as follows: Phase A/B = 441 volts, Phase A/C = 479 volts and Phase B/C = 457 volts Find the voltage unbalance and determine if this is acceptable.
b) A fault occurs at bus 3 of the network shown in Figure Q4. Pre-fault nodal voltages throughout the network are of 1 p.u. and the impedance of the electric arc is neglected. Sequence impedance parameters of the generator, transmission lines, transformer and load are given in Figure Q4. V₁ = 120° p.u. V₂ = 120° p.u. V₂ = 1/0° p.u. V₂= 120° p.u. jXj0.1 p.u. JX2) 0.1 p.u. jX0j0.15 p.u. jXn-j0.2 p.u. 1 JX(2)-j0.2 p.u. 2 jX)=j0.25 p.u. JX20-10.15 p.u. jXa(z)-j0.2 p.u. 4 jX2(0)=j0.2 p.u. jXT(1) j0.1 p.u. jXT(2)=j0.15 p.u. jXT(0)=j0.1 p.u. Figure Q4. Circuit for problem 4b). = jXj0.1 p.u. j0.1 p.u. - JX(2) JXL(0) 10.1 p.u. = (i) Assuming a balanced excitation, draw the positive, negative and zero sequence Thévenin equivalent circuits as seen from bus 3. (ii) Determine the positive sequence fault current for the case when a three- phase-to-ground fault occurs at bus 3 of the network. (iii) Determine the short-circuit fault current for the case when a one-phase- to-ground fault occurs at bus…
A three phase,Y connected, 215 V (line to line), 7.5 kW, 60 Hz, three pole IM has the following parameter values in Ohm/phase referred to the statorR₁ = 0.294 Ohm, R₂ = 0.144 Ohm, X₁ = 0.203 Ohm, X₂ = 0.409 Ohm, Xm = 10.25 Ohm.The total friction,windage and core losses may be assumed to be constant at 350 W independent of load. For a slip s = 0.02, compute the followingsa) Stator Currentb) Power Factor(pf)c) Rotor Speedd) Power Output(Shaft)e) Output(Shaft) Torquef) Efficiency(n)
For 4 pole d.c machine armature winding with a double layer progressive simplex wave winding with 23 number of slots answer the following: a How many coils are present? b What is the coil span in terms of number of slots? c What is commutator pitch in terms of commutator segments? d How many coils are there between two consecutive commutator segments? e How many parallel paths are present?
CALCULATE REACTANCE( NEED ONLY HANDWRITTEN SOLUTION PLEASE OTHERWISE DOWNVOTE).
Q2. The single-line diagram of a simple three-bus power system is shown in Figure-2. Each generator is represented by an emf behind the sub-transient reactance. All impedances are expressed in per unit on a common MVA base. All resistances and shunt capacitances are neglected. The generators are operating on no load at their rated voltage with their emfs in phase. A three-phase fault occurs at bus 3 through a fault impedance of Zf = j0.19 per unit. (i) Using Th'evenin's theorem, obtain the impedance to the point of fault and the fault current in (ii) Determine the bus voltages per unit. ) j0.05 j0.075 j0.75 2 j0.30 j0.45 Figure-2: Single line diagram of the power system network for Q2 3
Find the line fault current of the feeders shown in the figure and the T.S.M of Relay 2. Knowing that actual time of operation of Relay 2 is 1.4 Sec, the time margin between the two relays is 0.6 Sec, and the time setting multiplier (T.S.M.) of Relay 1 is 0.4. Use the I.D.M.T curve shown below. Bec 500/5 00/S CB2 Relay 2 160% Relay 1 120% PSM