4. A 2000-VA 230/115-V transformer has been tested to determine its equivalent circuit. The results of the tests are shown below. Open-circuit test VOC-230 V loc=0.45 A POC=30 W Short-circuit test VSC-13.2 V ISC = 6.0 A PSC =20.1 W All data given were taken from the primary side of the transformer. (a) Find the equivalent circuit of this transformer referred to the low-voltage side of the transformer. (b) Find the transformer's voltage regulation at rated conditions and (1) 0.8 PF lagging, (2) 1.0 PF, (3) 0.8 PF leading. (c) Determine the transformer's efficiency at rated conditions and 0.8 PF lagging.

4. A 2000-VA 230/115-V transformer has been tested to determine its equivalent circuit. The results of the tests are shown below. Open-circuit test VOC-230 V loc=0.45 A POC=30 W Short-circuit test VSC-13.2 V ISC = 6.0 A PSC =20.1 W All data given were taken from the primary side of the transformer. (a) Find the equivalent circuit of this transformer referred to the low-voltage side of the transformer. (b) Find the transformer's voltage regulation at rated conditions and (1) 0.8 PF lagging, (2) 1.0 PF, (3) 0.8 PF leading. (c) Determine the transformer's efficiency at rated conditions and 0.8 PF lagging.

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 3.27P: A three-phase transformer is rated 1000MVA,220Y/22kV. The Y-equivalent short-circuit impedance,...

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For the transformer in Problem 3.10. The open-circuit test with 11.5 kV applied results in a power input of 65 kW and a current of 30 A. Compute the values for GcandBm in siemens referred to the high-voltage winding. Compute the efficiency of the transformer for a load of 10 MW at 0.8 p.f. lagging at rated voltage.
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.
Rework Problem 3.14 if the transformer is delivering rated load at rated secondary voltage and at (a) unity power factor, (b) 0.8 power factor leading. Compare the results with those of Problem 3.14. -
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