Concept explainers
In developing per-unit equivalent circuits for three-phase transformers. under balanced three-phase operation.
(i) A common
(ii) The ratio of the voltage bases
(a) Only one of the above is true.
(b) Neither is true.
(C) Both statements are true.
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- For developing per-unit equivalent circuits of single-phase three-winding transformer, a common Sbase is selected for all three windings and voltage bases are selected in proportion to the rated voltage of the windings (a) True (b) Falsearrow_forwardTo convert a per-unit impedance from old to new base values, the equation to be used is Zp.u.new=Zp.u.old(VbaseoldVbasenew)2(SbasenewSbaseold)Zp.u.new=Zp.u.old(VbaseoldVbasenew)2(SbasenewSbaseold)Zp.u.new=Zp.u.old(VbaseoldVbasenew)2(SbasenewSbaseold)arrow_forwardConsider three ideal single-phase transformers (with a voltage gain of ) put together as three-phase bank as shown in Figure 3.35. Assuming positive-sequence voltages for Va,Vb, and Vc find Va,Vb, and VC. in terms of Va,Vb, and Vc, respectively. (a) Would such relationships hold for the line voltages as well? (b) Looking into the current relationships, express IaIb and Ic in terms of IaIb and Ic respectively. (C) Let S and S be the per-phase complex power output and input. respectively. Find S in terms of S.arrow_forward
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- Power System Analysis and Design (MindTap Course ...Electrical EngineeringISBN:9781305632134Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. SarmaPublisher:Cengage Learning