2. 3 of 1.6 kW. Determine the R power factor. Determine the efficiency at half load 0.8 p.f. leading. A 200 kVA transformer has an efficiency of 98% at full load. If the maximum efficiency occurs at three quarters of full load, calculate the efficiency at half load. Assume negligible magnetizing current and p.f. 0.8 at all loads. AALVA 200/400 V single phase transformer has equivalent resistance and reactance referred to low

2. 3 of 1.6 kW. Determine the R power factor. Determine the efficiency at half load 0.8 p.f. leading. A 200 kVA transformer has an efficiency of 98% at full load. If the maximum efficiency occurs at three quarters of full load, calculate the efficiency at half load. Assume negligible magnetizing current and p.f. 0.8 at all loads. AALVA 200/400 V single phase transformer has equivalent resistance and reactance referred to low

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 3.4MCQ: An ideal transformer has no real or reactive power loss. (a) True (b) False

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Similar questions

For a short-circuit test on a 2-winding transformer, with one winding shorted, can you apply the rated voltage on the other winding? (a) Yes (b) No
A 23/230-kV step-up transformer feeds a three-phase transmission line, which in turn supplies a 150-MVA,0.8 lagging power factor load through a step-down 230/23-kV transformer. The impedance of the line and transformers at 230kVis18+j60. Determine the tap setting for each transformer to maintain the voltage at the load at 23 kV.
Consider the three single-phase two-winding transformers shown in Figure 3.37. The high-voltage windings are connected in Y. (a) For the low-voltage side, connect the windings in , place the polarity marks, and label the terminals a, b, and c in accordance with the American standard. (b) Relabel the terminals a, b, and c such that VAN is 90 out of phase with Va for positive sequence.
For an ideal transformer, the efficiency is (a) 0 (b) 100 (c) 50
Consider an ideal transformer with N1=3000andN2=1000 turns. Let winding 1 be connected to a source whose voltage is e1(t)=100(1| t |)volts for 1t1ande1(t)=0 for | t |1 second. A2- farad capacitor is connected across winding 2. Sketch e1(t),e2(t),i1(t),andi2(t) versus time t.
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.
A bank of three single-phase transformers, each rated 30MVA,38.1/3.81kV, are connected in Y- with a balanced load of three 1, Y-connected resistors. Choosing a base of 90MVA,66kV for the high-voltage side of the three-phase transformer. spify the base for the low-voltage side. Compute the per-unit resistance of the load on the base for the low-voltage side. Also, determine the load resistance in ohms referred to the high-voltage side and the per-unit value on the chosen base.
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.
The efficiency of a transformer at load 0.8 p.f. Lag is -- at load 0.8 p.f. Lead * equal less than more than none of these
In a transformer that has 10 times more turns on the secondary side (side 2) than on the primary side (side 1), the magnitude of the voltage/EMF across the windings on the secondary side, E₂ will be... O a.... 10 times lower than the voltage/emf on the primary side, E₁. O b.... the same as the voltage/emf on the primary side. O c.... always zero regardless of the voltage on the primary side, E₁. O d.... 10 times higher than the voltage/emf on the primary side, E₁.
1-A single-phase power system is shown in Figure below. The power source feeds a 100- kVA 14/2.4-kV transformer through a feeder impedance of 40.0 + j150 &. The transformer's equivalent series impedance referred to its low-voltage side is 0.12 + j0.5 &. The load on the transformer is 90 kW at 0.80 PF lagging and 2300 V. 40n j150n 0.12n j0.5n Load 90 kW 0.85 PF lagging source Source Feeder Transformer Load (transmission line) (a) What is the voltage at the power source of the system? (b) What is the power losses in the feeder?
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