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
Winter
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
Double
Half
One forth
06. A relay used on short transmission lines is
Reactance relay
Mho’s relay
Impedance relay
None
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
ZR > ZO
ZR < ZO
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
1
0.5
-1
0
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