Relays are used for phase faults on long line.

Which of the following relays is used on long transmission lines?

A

Impedance relay

B

Mho's relay

C

Reactance relay

D

None of the above

The phase lag produced by transportation relays

A

Is independent of frequency

B

Is inversely proportional to frequency

C

Increases linearly with frequency

D

Decreases linearly with frequency

Thermal overload relays are used to protect the motor against over current due to

A

short-circuits

B

heavy loads

C

grounds

D

all of the above

The inverse definite mean time relays are used for over current and earth fault protection of transformer against

A

heavy loads

B

internal short-circuits

C

external short-circuits

D

all of the above

The single phasing relays are used for the protection of

A

single phase motors only

B

two phase motors only

C

two single phase motors running in parallel

D

three phase motors

To protect most of the electrical equipment handling low power, the types of relays used are

A

Thermocouple

B

Electronic and bimetallic

C

Both (A) and (B)

D

None of the above

Switches and relays should be shown in this position with no operating force or applied energy:

A

Normal

B

Closed

C

Offset

D

Application

Discrimination between main and back up protection is provided by the use of relays which are

A

fact

B

sensitive

C

slow

D

none of the above

Overload relays are of type.

A

induction

B

solid state

C

thermal

D

electromagnetic

E

all above

Directional relays are based on flow of

A

power

B

current

C

voltage wave

D

all of the above

Relays are used for phase faults on long line.

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