Q9 A single-phase transformer, 2500 / 250 V, 50 kVA, 50 Hz has the following parameters, thePrimary and secondary resistances are 0.8 ohm and 0.012 ohm respectively, the primary andsecondary reactance are 4 ohm and 0.04 ohm respectively and the transformer gives 96% maximumefficiency at 75% full-load. The magnetizing component of-load current is 1.2 A on 2500 V side. 1-Draw the equivalent circuit referred to primary (H.V side) and inserts all the values in it 2- Find outAmmeter, voltmeter and wattmeter readings on open-circuit and short-circuit test. If supply is givento 2500 V side in both cases. Ans. O.C. Test (Vo= 2500 V, lo=1.24 A, Wo=781.25 w) S.C. Test (Vsc=164.924 V, Isc =20 A, Wsc =800 w )

Part 1: Equivalent Circuit Referred to the Primary (H.V.) SideTo draw the equivalent circuit…

Answered: Q9 A single-phase transformer, 2500 /…

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 3.9P

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A single-phase step-down transformer is rated 13MVA,66kV/11.5kV. With the 11.5 kV winding short-circuited, rated current flows when the voltage applied to the primary is 5.5 kV. The power input is read as 100 kW. Determine Req1andXeq1 in ohms referred to the high-voltage winding.
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The ratings of a three-phase three-winding transformer are Primary(1): Y connected 66kV,15MVA Secondary (2): Y connected, 13.2kV,10MVA Tertiary (3): A connected, 2.3kV,5MVA Neglecting winding resistances and exciting current, the per-unit leakage reactances are X12=0.08 on a 15-MVA,66-kV base X13=0.10 on a 15-MVA,66-kV base X23=0.09 on a 10-MVA,13.2-kV base (a) Determine the per-unit reactances X1,X2,X3 of the equivalent circuit on a 15-MVA,66-kV base at the primary terminals. (b) Purely resistive loads of 7.5 MW at 13.2 kV and 5 MW at 2.3kV are connected to the secondary and tertiary sides of the transformer, respectively. Draw the per- unit impedance diagram, showing the per-unit impedances on a 15-MVA,66-kV base at the primary terminals.
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