100 MVA, 55 kV three phase generator has a sub transient reactance of 8%. The generator supplies one motor over a transmission line having transformers at both ends as shown in Fig. The motor have rated input of 80 MVA 30 kV with 7% sub transient reactance. The rating of the sending end transformer, T1 is 60 MVA, 200 kV / 30 kV (Δ – Y) with leakage

100 MVA, 55 kV three phase generator has a sub transient reactance of 8%. The generator supplies one motor over a transmission line having transformers at both ends as shown in Fig. The motor have rated input of 80 MVA 30 kV with 7% sub transient reactance. The rating of the sending end transformer, T1 is 60 MVA, 200 kV / 30 kV (Δ – Y) with leakage

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 3.4P: A single-phase 100-kVA,2400/240-volt,60-Hz distribution transformer is used as a step-down...

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An infinite bus, which is a constant voltage source, is connected to the primary of the three-winding transformer of Problem 3.53. A 7.5-MVA,13.2-kV synchronous motor with a sub transient reactance of 0.2 per unit is connected to the transformer secondary. A5-MW,2.3-kV three-phase resistive load is connected to the tertiary Choosing a base of 66 kV and 15 MVA in the primary, draw the impedance diagram of the system showing per-unit impedances. Neglect transformer exciting current, phase shifts, and all resistances except the resistive 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?
The transformer of Problem 3.16 is supplying a rated load of 50 kVA at a rated secondary voltage of 240 V and at 0.8 posr factor lagging. Neglect the transformer exciting current. (a) Determine the input terminal voltage of the transformer on the high-voltage side. (b) Sketch the corresponding phasor diagram. (c) If the transformer is used as a step-down transformer at the load end of a feeder whose impedance is 0.5+j2.0, find the voltage VS and the power factor at the sending end of the feeder.
The motors M1andM2 of Problem 3.45 have inputs of 120 and 60 MW, respectively, at 13.2 kV, and both operate at unity power factor. Determine the generator terminal voltage and voltage regulation of the line. Neglect transformer phase shifts.
A single-phase 50-kVA,2400/240-volt,60-Hz distribution transformer is used as a step-down transformer at the load end of a 2400-volt feeder whose series impedance is (1.0+j2.0) ohm. The equivalent series impedance of the transformer is (1.0+j2.5) ohms referred to the high-voltage (primary) side. The transformer is delivering rated load at a 0.8 power factor lagging and at a rated secondary voltage. Neglecting the transformer exciting current, determine (a) the voltage at the transformer primary terminals, (b) the voltage at the sending end of the feeder, and (c) the real and reactive power delivered to the sending end of the feeder.
A 50 MVA, 15 kV three phase generator has a subtransient reactance of 0.2 p.u. The generator supplies two motors over a transmission line having transformers at both ends as shown in Fig. The motors have rated inputs of 30 MVA and 20 MVA both 30 kV with 0.15 p.u. subtransient reactance. The rating of the sending end transformer, Tr1 is 50 MVA, 11 kV / 132 kV with leakage reactance of 0.1 p.u. Transformer Tr2 at the receiving end has three single phase transformers and the rating of each individual transformer is 20 MVA , 33 / 76 kV with leakage reactance of 0.12 p.u. Series reactance of the line is 25 ohms. Draw the reactance diagram with all reactance marked in p.u. Select the generator rating as the base in the generator circuit.
2) A three -phase transformer of 90 kVA, 13200/480 V (line to line), with connection Delta-Delta, has a resistance of 1.3% and a reactance of 8.2% per unit. a) Calculate the phase impedance of the transformer referred to the high side strain. b) Calculate the phase impedance of the transformer referred to the low side strain. c) Calculate the transformer voltage regulation into nominal conditions with F.P.0,8 in delay.
A 400-turns auto transformer, operating in the step-down mode with 25 percent tap supplies a 4.8 kVA, 0.85 lagging power factor load. The input to the transformer is 2400 V, 60 Hz. Neglect the small losses and leakage effects. What will be the apparent power(in kVA) conducted and transformed respectively?
2. A 100 MVA, 18 kV generator, with per unit reactance of X”d= 0.19, X’d = 0.26, and Xd = 1.3 is connected through acircuit breaker to a transformer rated 100 MVA, 240Y/18 kV,X = 0.10 per unit. It is operating at no load and ratedvoltage when a three-phase short circuit occurs at the highvoltage side of the transformer. Find the initialsymmetrical rms current in the line on the low voltageside.
2.2. The figure below shows a radial transmission system with a generator having a per-unit voltage of 1.3 at an angle of 9 degree p.u. The load demand is 47MW at a power factor of 0.96lagging. Use the nameplate values of Transformer 2 as base values and calculate the following: Correct answers to three decimal places : 25..Per unit impedance of transformer and it's angle 26.Per unit voltage of the line and its angle 27.Per unit impedance of the line and its angle. And Reactance of the transmission line when the load consumes full-load (Ω).
A simple power system is shown in this Fig. The generator (480 V, 10 kVA) is connected to an ideal step-up transformer (1:10), a transmission line (R=20 Ohm and X=60 Ohm), step down transformer (20:1) and a load with magnitude Z=10 Ohm and angle =30 degree the base values for this system are chosen to be 480 V and 10 kVA at the generator. Calculate the per-unit impedance of the load. Calculate the per-unit real power absorbed by the load Select one: a. 0.487 b. None of the above c. 0.057 d. 1.253
1) A single-phase 100-kVA, 2,400/240 V, 60-Hz distribution transformer is used as a step-down transformer. The load, which is connected to the 240 V secondary winding, absorbs 80 kVA at 0.8 power factor lagging and is at 230 V. Assuming an ideal transformer, calculate the following: (a) primary voltage;(b) load impedance;(c) load impedance referred to the primary;(d) the active and reactive power supplied to the primary winding.