A 12kVA, 300V/150V transformer has been tested to determine its equivalent circuit. The open circuit test data when high voltage side is open: loc=1.8A, Poc=100W. The short circuit test data when low voltage side is short circuited: Vsc=40V, Psc=115W. Use approximate equivalent circuit. Calculate the full load output power at 0.85 pf leading. 9600W O 12000W O O 10200W 15000W 8400W

A 12kVA, 300V/150V transformer has been tested to determine its equivalent circuit. The open circuit test data when high voltage side is open: loc=1.8A, Poc=100W. The short circuit test data when low voltage side is short circuited: Vsc=40V, Psc=115W. Use approximate equivalent circuit. Calculate the full load output power at 0.85 pf leading. 9600W O 12000W O O 10200W 15000W 8400W

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 3.34MCQ: Consider Figure 3.25 of the text for a transformer with off-nominal turns ratio. (i) The per-unit...

See similar textbooks

Similar questions

(a) An ideal single-phase two-winding transformer with turns ratio at=N1/N2 is connected with a series impedance Z2 across winding 2. If one wants to replace Z2, with a series impedance Z1 across winding 1 and keep the terminal behavior of the two circuits to be identical, find Z1 in terms of Z2. (b) Would the above result be true if instead of a series impedance there is a shunt impedance? (c) Can one refer a ladder network on the secondary (2) side to the primary (1) side simply by multiplying every impedance byat2 ?
Consider an ideal transformer with N1=3000andN2=1000 turns. Let winding 1 be connected to a source whose voltage is e1(t)=100(1| t |)volts for 1t1ande1(t)=0 for | t |1 second. A2- farad capacitor is connected across winding 2. Sketch e1(t),e2(t),i1(t),andi2(t) versus time t.
An ideal transformer has no real or reactive power loss. (a) True (b) False
Consider Figure 3.25 of the text for a transformer with off-nominal turns ratio. (i) The per-unit equivalent circuit shown in part (c) contains an ideal transformer which cannot be accommodated by some computer programs. (a) True (b) False (ii) In the - circuit representation for real c in part (d), the admittance parameters Y11 and Y12 would be unequal. (a) True (b) False (iii) For complex c, can the admittance parameters be synthesized with a passive RLC circuit? (a) Yes (b) No
A two-winding single-phase transformer rated 60kVA,240/1200V,60Hz, has an efficiency of 0.96 when operated at rated load, 0.8 power factor lagging. This transformer is to be utilized as a 1440/1200-V step-down autotransformer in a power distribution system. (a) Find the permissible kVA rating of the autotransformer if the winding currents and voltages are not to exceed the ratings as a two-winding transformer. Assume an ideal transformer. (b) Determine the efficiency of the autotransformer with the kVA loading of part (a) and 0.8 power factor leading.
A single-phase, 50-kVA,2400/240-V,60-Hz distribution transformer has the following parameters: Resistance of the 2400-V winding: R1=0.75 Resistance of the 240-V winding: R2=0.0075 Leakage reactance of the 2400-V winding: X1=1.0 Leakage reactance of the 240-V winding: X2=0.01 Exciting admittance on the 240-V side =0.003j0.02S (a) Draw the equivalent circuit referred to the high-voltage side of the transformer. (b) Draw the equivalent circuit referred to the low-voltage side of the transformer. Show the numerical values of impedances on the equivalent circuits.
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.
For an ideal 2-winding transformer, an impedance Z2 connected across winding 2 (secondary) is referred to winding 1 (primary) by multiplying Z2 by (a) The turns ratio (N1/N2) (b) The square of the turns ratio (N1/N2)2 (c) The cubed turns ratio (N1/N2)3
A 1000-VA, 230/115-V traformer has been tested to determine its equivalent circuit. The results are shown below: Open-Circuit Test results from the low voltage side: VOC = 115 V, IOC = 0.1 A, POC = 5 W; Short-Circuit Test results from the high voltage side: VSC = 20 V, ISC = 10 A, PSC = 50 W; Find the transformer’s voltage regulation, in percent, at 50% loading conditions and 0.8 PF lagging. Note: (If %1, the you should write as '1', not as '0,01')
3) The results of an open circuit test and a short circuit test In a 450 kVA transformer, 42000/2400 V, 60 Hz are the following: Open circuit test (low voltage side) VCA = 2400 V ICA = 18,1 A PCA = 3785 in Short circuit test (High voltage side) Vcc = 1910 V Icc = 11,9 A PCC3850 W a) Find the equivalent circuit of the transformer referred to the bass side voltage. b) Calculate the efficiency of the transformer at full load with a factor of Power of 0.85 in delay.
A step-down transformer is rated 10kVA, 7500/250 V and has the following equivalent circuit parameters:Rp = 2.92 Ω Rs = 0.00432 Ω Rm = 51,840 ΩXp = 14.6 Ω Xs = 0.02160 Ω Xm = 12,960 ΩAssume that this transformer is supplying rated load at 250 V and 0.85 PF lagging.(i)Find the equivalent winding impedance referred to the high voltage side.(ii)Determine this transformer’s input voltage.(iii)Determine its voltage regulation.
The diagram shown below is a typical tuning circuit. Considering this circuit comprises a transformer (with a coil ratio of 20:1 and an HV side voltage of 240V ), a capacitor of impedance -j20Ω, an inductor of impedance j40Ω, and a 50Ω resistor, determine: the current supplied by the source (0.2228) the impedance seen at the supply (HV side)(21540.55) the power dissipated by the resistor(2.482 watts) the operating power factor of the fitting(0.928 lagging) If the capacitor is now removed from the above circuit and is placed in parallel with the secondary of the transformer, redraw the circuit diagram and recalculate parts a. to d. in question (i). Draw the phasor diagram for both series and parallel RLC circuits in parts (i) and (ii). Discuss the effects of changing the capacitor connection in parallel on the power factor of the circuit. State the benefits of using the transformer in the above circuit. Explain the operating principle of the transformer with particular reference to…