A 10 MVA, 115 kV/25 kV, 60 Hz, Y-A connected, three-phase power transformer has an equivalent series impedance of 0.03+j0.15 pu. The core loss resistance of the transformer is 100 pu and the magnetizing reactance is 30 pu. a) What is the transformer series impedance in N/phase referred to the HV side? b) The above transformer is used to deliver 7.5 MW at a voltage of 24 kV to a three-phase load with 0.866 lagging power factor. Determine the magnitude of the line-to-line voltage (in kV) applied at the primary side of the transformer (use per unit basis for the calculation). c) Determine the primary side line current (in A) and the efficiency of the transformer bank under the conditions in Part (b) (use per unit basis for the calculation).

A 10 MVA, 115 kV/25 kV, 60 Hz, Y-A connected, three-phase power transformer has an equivalent series impedance of 0.03+j0.15 pu. The core loss resistance of the transformer is 100 pu and the magnetizing reactance is 30 pu. a) What is the transformer series impedance in N/phase referred to the HV side? b) The above transformer is used to deliver 7.5 MW at a voltage of 24 kV to a three-phase load with 0.866 lagging power factor. Determine the magnitude of the line-to-line voltage (in kV) applied at the primary side of the transformer (use per unit basis for the calculation). c) Determine the primary side line current (in A) and the efficiency of the transformer bank under the conditions in Part (b) (use per unit basis for the calculation).

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 3.57P: A two-winding single-phase transformer rated 60kVA,240/1200V,60Hz, has an efficiency of 0.96 when...

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Consider Figure 3.4. For an ideal phase-shifting transformer, the imda nce is unchanged when it is referred from one side to the other. (a) True (b) False
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