MGVCL Exam Paper (30-07-2021 Shift 2)
In transformer, a Sweep Frequency Response Analysis (SFRA) test will help detect ____

Aging by-products
Age of the insulation
Movement / damage to internal components
Moisture in the windings

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MGVCL Exam Paper (30-07-2021 Shift 2)
A 50 Hz synchronous generator is connected to an infinite bus through a line. The p.u. reactances of generator and the line are j0.3 p.u. and j0.2 p.u. respectively. The generator no load voltage is 1.1 p.u. and that of infinite bus is 1.0 p.u. The inertia constant of the generator is 4 MW-sec/MVA. Determine the frequency of natural oscillations if the generator is loaded to 60% of its maximum power transfer capacity and small perturbation in power is given.

1.62 Hz
1.52 Hz
1.42 Hz
1.32 Hz

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MGVCL Exam Paper (30-07-2021 Shift 2)
The magnitude of the generator earth-fault current is limited by

using higher rating CTs
inserting suitable resistance in neutral grounding circuit
controlling field exciter
inserting the stabilizing resistance in series with the relay

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MGVCL Exam Paper (30-07-2021 Shift 2)
Which one of the following statement is TRUE?

The current carrying capacity of cables in DC is less than that in AC.
In the cables, the location of fault is usually found out by comparing the capacitances of insulated conductors.
Underground cables are laid at sufficient depth to avoid being unearthed easily due to removal of soil.
In the cables, sheaths are used to provide enough strength.

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