Power System Analysis and Design (MindTap Course List)
6th Edition
ISBN: 9781305632134
Author: J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma
Publisher: Cengage Learning
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Three zones of a single-phase circuit are identified in the figure. The zones are connected by
transformers T₁ and T2, whose ratings are also shown. Using base values of 100 kVA and 240 volts in
zone 1, draw the per-unit circuit and determine the per-unit impedances and the per-unit source
voltage. Then calculate the load current both in per-unit and in amperes. Transformer winding
resistances and shunt admittance branches are neglected.
Zone 1
Zone 2
Vs = 220/0° volts
3---38
T,
30 KVA
240/480 volts
M 0.10 p.u.
Xoa
Xune = 2 fl
T
T₂
20 kVA
460/115 volts
Xeg = 0.10 p.u.
Zone 3
ww
Zload = 0.9 - 10.20
Three zones of a single-phase circuit are identified in Figure. The zones are connected bytransformers T1 and T2, whose ratings are also shown.Using base values of 30 kVA and 240 volts in zone 1:a. draw the per-unit circuit and determine the per-unit impedances and the per-unitsource voltage.b. calculate the load current both in per-unit and in amperes. Transformer windingresistances and shunt admittance branches are neglected.
1. For this question you are to sketch two transformers (T1 and T2) side by side
connected in PARALLEL. Be sure to employ alphanumeric polarity markings for each
transformer with the LV windings on the TOP and the HV windings on the BOTTOM.
T1 should have ADDITIVE polarity and T2 should have SUBTRACTIVE polarity. Include
a source bus voltage [REFERENCE] above the transformers and a single-phase load.
Indicate the direction of all voltages with respect to the reference direction. Based
on the preceding requirements, provide a complete SCHEMATIC diagram showing
how the two transformers should be connected for proper PARALLEL operation.
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