Power Systems Mcqs

01. In order to reduce skin effect at UHF

Conductors are painted

Conductors are anodised

Copper tubes with silver plating are used

Copper rods with silver plating are used

02. Shunt capacitance is usually neglected in the analysis of

Short transmission lines

Medium transmission lines

Long transmission lines

Medium as well as long transmission lines

03. The chances of corona are maximum during

Summer heat


Dry weather

Humid weather

04. The power transmitted will be maximum when

Sending end voltage is more

Recieving end voltage is more

Reactance is high

Corona losses are least

05. Neglecting losses in a transmission system, if the voltage is doubled, for the same power transmission, the weight of conductor material require will be

Four times



One forth

06. A relay used on short transmission lines is

Reactance relay

Mho’s relay

Impedance relay


07. In case of characteristic impedance of the line is equal to the load impedance

All the energy will pass to the earth

All the energy will be lost in transmission losses

The system will resonate badly

All the energy sent will be absorbed by the load

08. For a properly terminated line




ZR = ZO = 0

09. The dielectric strength of air at 25 C and 76 cm/Hg is

1 point

1 kV/cm

1 kV/mm

3 kV/cm

30 kV/cm

10. The chances of corona are maximum in

Domestic wiring

Distribution lines

Transmission lines

All of the above

11. Transmission lines link

Service point to consumer premises

Distribution transformer to consumer premises

Recieving end station to distribution tranformer

Generating station to recieving end station

12. In case of open circuit transmission lines the reflection coefficient is





13. Impedance relay is used on

Short transmission lines

Medium transmission lines

Long transmission lines

All the transmission lines

14. Which type of insulator are used on 132 kV transmission lines ?

Pin type

Disc type

Shackle type

Pin and shackle type

15. String efficiency can be improved by

Using longer cross arm

Grading the insulator

Using guard ring

Any of the above

16. If a 66 kV lines passes over a residential building, the minimum vertical clearance from the roof of the building must be

8 feet

12 feet

13 feet

16 feet

17. Alternating current power is transmitted at high voltage

To safeguard against pilferage

To minimize transmission losses

To reduce cost of generation

To make the system relaible

18. Stranded conductors are used for transmitting power at high voltage because of

Increased tensile strength

Better wind resistance

Ease in handling

Low cost

19. The function of steel wire in a ACSR conductor is

To take care of surges

To prevent corona

To reduce inductance and hence improve power factor

To provide additional mechanical strength

20. In high voltage transmission lines, the top most conductor is

R- phase conductor

Y- phase conductor

B- phase conductor

Earth Conductor

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