GATE 2014 EE (EE2) – Question 25

Power Systems · Per-unit quantities, Bus admittance matrix, Gauss-Seidel and Newton-Raphson load flow methods · 1 mark · Numerical answer

A three-phase star load operates at 0.9 pu voltage and 0.8 lagging power factor. Base three-phase power and current are 100 MVA and 437.38 A. Find line-to-line load voltage (kV).

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Correct answer: 117 to 120

Explanation

Three-phase base apparent power obeys Sb=√3VbIb. Thus Vb=100×10^6/(√3×437.38)≈132.003kV. The specified0.9pu load voltage is **118.803kV**. Power factor is unnecessary because base apparent power,not base real power,is given.