5. A substation takes 1,200 kW, 3-phase power, @ 66kV, and this power is stepped down to 4,800V by two V-connected transformers. The load power factor is 0.866 lagging. Determine (a) minimum rating of each transformer; (b) current and voltage rating of each winding; (c) power factor at which each winding operates. Neglect losses. A third transformer of the same rating as these two is added. Determine (d) rating in kilowatts of substation at power factor of 0.866 lagging: (e) percentage increase, in kilowatt rating and percentage increase in transformer investment. . Answer: (a) kVArach 799.54kVA; (b) In 1.0 (Unity). P.F.2 0.50 lagging; (d) kW Investment 50% 12.12A, Is-166.67A, Vp 66,000V, Vs 4,800V: (c) P.F.:- 2,077.20kW; (e) %increase in kWR 73.10 %, %increase in

5. A substation takes 1,200 kW, 3-phase power, @ 66kV, and this power is stepped down to 4,800V by two V-connected transformers. The load power factor is 0.866 lagging. Determine (a) minimum rating of each transformer; (b) current and voltage rating of each winding; (c) power factor at which each winding operates. Neglect losses. A third transformer of the same rating as these two is added. Determine (d) rating in kilowatts of substation at power factor of 0.866 lagging: (e) percentage increase, in kilowatt rating and percentage increase in transformer investment. . Answer: (a) kVArach 799.54kVA; (b) In 1.0 (Unity). P.F.2 0.50 lagging; (d) kW Investment 50% 12.12A, Is-166.67A, Vp 66,000V, Vs 4,800V: (c) P.F.:- 2,077.20kW; (e) %increase in kWR 73.10 %, %increase in

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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13)This MCQ QUESTION FROM BASIC POWER ELECTRICAL ENGINEERING course.
The test results of a 5 kVA, 400/200 V, 50 Hz, single phase transformer are as follows. O.C. Test: 400 V, 1 A, 50 W, H.V. side S.C. Test: 12 V, 12.5 A, 60 W, H.V. side Find the full load efficiency and regulation when the power factor is 0.8 lagging.
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The maximum efficiency of a 200KVA, 6000/230volt, 50HZ, single phase transformer occurs at half load and is 95% at unity power factor. What is the full load efficiency at 0.7 power factor?