MCQs

Arcing currents during earth faults are suppressed using: Peterson coil Copper tape Ground wire Circuit breaker Correct answer: 1. Peterson coil

Distance protection scheme is employed for which power structure: Alternator Transformer Transmission lines Induction motors Correct answer: 3. Transmission lines

Merz-price current circulating scheme is uneconomical for which type of power device/structure: Alternator Transformer Transmission lines Induction motors Correct answer: 3. Transmission lines

Earthing screen provides protection against: Direct lightning strikes Indirect lightning strikes Short circuits Open circuits Correct answer: 1. Direct lighting strikes

Differential protection system in transformers is used for providing protection against: Earth faults only Phase faults only Both of these None of these Correct answer: 3. Both of these

Location of surge diverter for protection of the apparatus should be: In close proximity to equipment Far away from equipment Any of above Correct answer: 1. In close proximity to equipment

The successful working of grounding wire requires: Low footing resistance High footing resistance Very high footing resistance None of above Correct answer: 1. Low footing resistance

A 1/100 μs voltage surge reaches its maximum value in: 0.01 μs 1 μs 100 μs 1000 μs Correct answer: 2.1 μs

A 1/100 μs voltage surge decays to half of its peak value in: 0.01 μs 1 μs 100 μs 1000 μs Correct answer: 2.100 μs

The device which signals breaker under fault condition: Isolator Fuse Transformer Relay Correct answer: 4. Relay