2) 50 kVA, 2300 V / 230 V transformer draws 750 W power and 0.5 A current at rated idle primary voltage. If the high voltage side ohmic resistance and reactance are 1.8 ohms and 4 ohms respectively: (a) Idle power factor (b) Primary side inverse EMF value (c) Magnetizing current (d) Calculate the core loss component of the no-load current.

2) 50 kVA, 2300 V / 230 V transformer draws 750 W power and 0.5 A current at rated idle primary voltage. If the high voltage side ohmic resistance and reactance are 1.8 ohms and 4 ohms respectively: (a) Idle power factor (b) Primary side inverse EMF value (c) Magnetizing current (d) Calculate the core loss component of the no-load current.

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 3.58P: A single-phase two-winding transformer rated 90MVA,80/120kV is to be connected as an autotransformer...

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Similar questions

A single-phase two-winding transformer rated 90MVA,80/120kV is to be connected as an autotransformer rated 80/200kV. Assume that the transformer is ideal. (a) Draw a schematic diagram of the ideal transformer connected as an autotransformer. showing the voltages, currents, and dot notation for polarity. (b) Determine the permissible kVA rating of the autotransformer if the winding currents and voltages are not to exceed the rated values as a two-winding transformer. How much of the kA rating is transferred by magnetic induction?
Three single-phase, two-winding transformers, each rated 450MVA,20kV/288.7kV, with leakage reactance Xeq=0.10perunit, are connected to form a three-phase bank. The high-voltage windings are connected in Y with a solidly grounded neutral. Draw the per-unit equivalent circuit if the low-voltage windings are connected (a) in with American standard phase shift or (b) in Y with an open neutral. Use the transformer ratings as base quantities. Winding resistances and exciting current are neglected.
A single-phase 50-kVA,2400/240-volt,60-Hz distribution transformer is used as a step-down transformer at the load end of a 2400-volt feeder whose series impedance is (1.0+j2.0) ohm. The equivalent series impedance of the transformer is (1.0+j2.5) ohms referred to the high-voltage (primary) side. The transformer is delivering rated load at a 0.8 power factor lagging and at a rated secondary voltage. Neglecting the transformer exciting current, determine (a) the voltage at the transformer primary terminals, (b) the voltage at the sending end of the feeder, and (c) the real and reactive power delivered to the sending end of the feeder.
The ideal transformer windings are eliminated from the per-unit equivalent circuit of a transformer. (a) True (b) False
The leakage reactance of a three-phase, 300-MVA,230Y/23-kV transformer is 0.06 per unit based on its own ratings. The Y winding has a solidly grounded neutral. Draw the per-unit equivalent circuit. Neglect the exciting admittance and assume the American Standard phase shift.
Consider the oneline diagram shown in Figure 3.40. The three-phase transformer bank is made up of three identical single-phase transformers, each specified by X1=0.24 (on the low-voltage side), negligible resistance and magnetizing current, and turns ratio =N2/N1=10. The transformer bank is delivering 100 MW at 0.8 p.f. lagging to a substation bus whose voltage is 230 kV. (a) Determine the primary current magnitude, primary voltage (line-to-line) magnitude, and the three-phase complex power supplied by the generator. Choose the line-to-neutral voltage at the bus, Va as the reference Account for the phase shift, and assume positive-sequence operation. (b) Find the phase shift between the primary and secondary voltages.
For an ideal 2-winding transformer, the ampere-turns of the primary winding, N1I1 is equal to the ampere-turns of the secondary winding, N2I2 (a) True (b) False
A single-phase 100-kVA,2400/240-volt,60-Hz distribution transformer is used as a step-down transformer. The load, which is connected to the 240-volt secondary winding, absorbs 60 kVA at 0.8 power factor lagging and is at 230 volts. Assuming an ideal transformer, calculate the following: (a) primary voltage, (b) load impedance, (c) load impedance referred to the primary, and (d) the real and reactive power supplied to the primary winding.
Consider a bank of this single-phase two-winding transformers whose high-voltage terminals are connected to a three-phase, 13.8-kV feeder. The low-voltage terminals are connected to a three-phase substation load rated 2.0 MVA and 2.5 kV. Determine the required voltage, current, and MVA ratings of both windings of each transformer, when the high-voltage/low- voltage windings are connected (a) Y-, (b) -Y, (c) Y-Y, and (d) -.
An ideal transformer has no real or reactive power loss. (a) True (b) False
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 ratings of a three-phase, three-winding transformer are Primary: Y connected, 66kV,15MVA Secondary: Y connected, 13.2kV,10MVA Tertiary: connected, 2.3kV,5MVA Neglecting resistances and exciting current, the leakage reactances are: XPS=0.09 per unit on a 15-MVA,66-kV base XPT=0.08 per unit on a 15-MVA,66-kV base XST=0.05 per unit on a 10-MVA,13.2-kV base Determine the per-unit reactances of the per-phase equivalent circuit using a base of 15 MVA and 66 kV for the primary.