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Period and Frequency of AC Generator

A synchronous...

Question

A synchronous generator having synchronous reactance of 1.0 pu is connected to infinite busbar of 1.0 p.u voltage through 2 parallel lines each of 0.5 p.u. reactance. The generator excitation when it is delivering zero active power and 0.5 pu lagging reactive power to the infinite busbars is____ p.u.
1.62

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Solution

The correct option is A 1.62
Circuit model is as shown

Phasor diagram is as shown

$Q = E_{b} I_{a} sin ϕ$

$\Rightarrow 0.5 = 1.0 \times I_{a} \times sin 90^{\circ}$

$\Rightarrow I_{a} = 0.5 p . u$

From phasor diagram,

$E_{f} = 1.625 p . u .$

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