MCQ 1
1. Current carrying capacity of cable reduces if ___________ increases.
a) Thermal resistance
b) I2R losses
c) Both a and b
d) only b
2. The regulation of Short Transmission lines depends up on
a) Distance of line
b) Frequency
c) Power factor
d) All
3. A wave will not experience any reflection when impedance of line is equal to
a ) surge impedance
b ) load impedance
c ) >surge impedance
d ) none
4. Which of the following is the property of copper as conducting material?
a) High
b) Low
c) High specific
mechanical
conductivity
Specific gravity
strength
5. If receiving end voltage is greater than sending end voltage, regulation is
a) Positive
b) Negative
c) Zero
6. Charging current in the transmission line
a) Lags the
b) Leads the
voltage by 90
voltage by 45
c) Leads the
voltage by 90
8. Value of charging current at receiving end is
a) less
b) more
c) same
d)
none
d) None
d) Leads the
voltage by 180
e)
7. In overhead transmission lines the effect of capacitance can be neglected when the length of line is
less than
a) 200km
b) 160km
c) 100km
d)80km
d) none
9. A typical value of characteristic impedance for a double circuit line is
a) 100 ohms
b) 200 ohms
c) 300 ohms
d) None
10. The ionization air surrounding the power conductor is known as
a) corona
b) sag
c) Ferranti effect
d) None
11. Frequency of supply being high, corona losses are
a) Higher
b) Lower
d) None
c) Unchanged
12. DC corona loss is ____________ than AC corona loss
a) Less
b) More
c) Same
13. Corona losses are reduced by using ________ conductors
d) None
a) Large diameter
b) Hollow
c) Bundled
14. Characteristic impedance for a loss less line is called
a) Transmission
b) Intermediate
c) Surge
impedance
impedance
impedance
15. The advantage of the cables over overhead transmission line
a) Easy maintenance
b) Low cost
c) Can be used in
congested areas
d) None
d) All these
d) Can be used in
high voltage
circuits
16. What current is drawn by a 20 W lamp connected to a 230 V,60 Hz source.
a) 1 A
b) 0.5 A
c ) 0.37 A
d ) 0.087 A
17. Nominal Pi- model can be used for
a) Short T/L
b) Medium T/L
c) long T/L
d) both b&c
18. On no load in High voltage lines what is the relation between receiving and sending end voltage?
a) receiving end voltage > sending end voltage
b) receiving end voltage < sending end voltage
c) receiving end voltage = sending end voltage
d) none
19. What is the surge impedance loading of 500kv line where L=C=1 is ?
a) 2.5 MW
b) 400 KW
c) 0.25 MW
20. The insulation material should have
a) High resistance
b) High mechanical strength
d) 250 KW
c) High permeability
21. Self GMD is used in the calculation of_______
a )inductance only
b) inductance and
c) capacitance only
capacitance
22 Conductors for high voltage transmission lines are suspended from towers
a) to reduce
b) to increase
c) to reduce wind
clearance
clearance from
and snow
from ground
ground
loads
23. _______ is used to keep the conductor apart from tower.
a) insulator
b) grounding wire
c) cross arm
24. String efficiency of an insulator cannot be improved by
a) guard ring
b) longer cross arms
c) using lesser
number of discs
d) A&B
d) none
d) to take care
of extension
in length
during
summer
d) isolator
e)
d) none
25. What is the GMR if the distance between the filaments of the conductors is 6m,6m,12m and radius
of each conductor is 0.25 cm?
a) 10 m
b)0.06m
c )0.481m
e) 8.56m
26. Sag is provided in transmission line to provide _________________
a) strength
b) safe tension
c) good voltage
profile
27. Minimum dielectric stress in the cable is at ______________
a )surface
b) lead sheath
c ) both
28. When an insulator breaks down by puncture, it damages _______________
a) partially
b) permanently
c) doesn’t
damages
d) none
d)none
d) none
29. Underground cables are laid at sufficient depth
a) To minimize the effect of shocks and
b) To avoid being unearthed easily due to
vibrations
removal of soil
c) to minimize temperature stresses
d) All of these
30. Which of the following is the test performed for locating faults in cables
a) Uric acid
b) Cretonnes loop
c) Varley loop test
test
test
d) All
Mark true and false from following.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
Corona discharges emit radiations which induce noise signals in the communication channel? T
Power factor of load decreases, the line losses decreases? F
Conductance effect is normally taken as negligible in transmission lines? T
Capacitance is calculated in series for transmission lines? F
Line to neutral capacitance is normally half of the line to line capacitance? T
Charging current is responsible for increasing power factor? F
The term “charging currents” is associated with the inductance of line? F
Effect of earth on capacitance of transmission line is due to distance of conductors from earth? T
Capacitance normally decreases as distance from earth decreases? F
Laying cables for distribution is economical then overhead lines. T
MCQ 2
1. Current carrying capacity of cable reduces if ___________ increases.
a) Thermal resistance
b) I2R losses
c) Both a and b
d) only b
2. The regulation of Short Transmission lines depends up on
a) Distance of line
b) Frequency
c) Power factor
d) All
3. A wave will not experience any reflection when impedance of line is equal to
a ) surge impedance
b ) load impedance
c ) >surge impedance
d ) none
4. Which of the following is the property of copper as conducting material?
e) High
f) Low
g) High specific
mechanical
conductivity
Specific gravity
strength
h)
5. If receiving end voltage is greater than sending end voltage, regulation is
e) Positive
f) Negative
g) Zero
6. Charging current in the transmission line
f) Lags the
g) Leads the
voltage by 90
voltage by 45
h) Leads the
voltage by 90
none
h) None
i)
Leads the
voltage by 180
7. In overhead transmission lines the effect of capacitance can be neglected when the length of line is
less than
a) 200km
b) 160km
c) 100km
d)80km
8. Value of charging current at receiving end is
e) less
f) more
g) same
h) none
9. A typical value of characteristic impedance for a double circuit line is
e) 100 ohms
f) 200 ohms
g) 300 ohms
h) None
10. The ionization air surrounding the power conductor is known as
e) corona
f) sag
g) Ferranti effect
11. Frequency of supply being high, corona losses are
e) Higher
f) Lower
g) Unchanged
h) None
h) None
i)
12. DC corona loss is ____________ than AC corona loss
e) Less
f) More
g) Same
h) None
13. Corona losses are reduced by using ________ conductors
e) Large diameter
f) Hollow
g) Bundled
h) None
14. Characteristic impedance for a loss less line is called
e) Transmission
f) Intermediate
impedance
impedance
g) Surge
impedance
h) All these
15. The advantage of the cables over overhead transmission line
e) Easy maintenance
f) Low cost
g) Can be used in
congested areas
h) Can be used in
high voltage
circuits
16. What current is drawn by a 20 W lamp connected to a 230 V,60 Hz source.
a) 1 A
b) 0.5 A
c ) 0.37 A
d ) 0.087 A
17. Nominal Pi- model can be used for
e) Short T/L
f) Medium T/L
g) long T/L
h) both b&c
18. On no load in High voltage lines what is the relation between receiving and sending end voltage?
a) receiving end voltage > sending end voltage
b) receiving end voltage < sending end voltage
c) receiving end voltage = sending end voltage
d) none
19. What is the surge impedance loading of 500kv line where L=C=1 is ?
a) 2.5 MW
b) 400 KW
c) 0.25 MW
20. The insulation material should have
e) High resistance
f) High mechanical strength
d) 2500 MW
g) High permeability
21. Self GMD is used in the calculation of_______
a )inductance only
b) inductance and
c) capacitance only
capacitance
22 Conductors for high voltage transmission lines are suspended from towers
e) to reduce
f) to increase
g) to reduce wind
clearance
clearance from
and snow
from ground
ground
loads
h) A&B
d) none
h) to take care
of extension
in length
during
summer
23. _______ is used to keep the conductor apart from tower.
f) insulator
g) grounding wire
h) cross arm
i) isolator
24. String efficiency of an insulator cannot be improved by
f) guard ring
g) longer cross arms
h) using lesser
i) none
number of discs
25. What is the GMR if the distance between the filaments of the conductors is 6m,6m,12m and radius
of each conductor is 0.25 cm?
a) 10 m
b)0.06m
c )0.481m
d) 8.56m
26. Sag is provided in transmission line to provide _________________
e) strength
f) safe tension
g) good voltage
h) none
profile
27. Minimum dielectric stress in the cable is at ______________
a )surface
b) lead sheath
c ) both
d)none
28. When an insulator breaks down by puncture, it damages _______________
e) partially
f)
permanently
g) doesn’t
damages
h) none
29. Underground cables are laid at sufficient depth
e) To minimize the effect of shocks and
f) To avoid being unearthed easily due to
vibrations
removal of soil
g) to minimize temperature stresses
h) All of these
30. Grounding wire in HV line is installed for __________
e) Improving f) Minimizing
efficiency
losses
g) Lightening surges
h) none
MCQ 3
1. Current density is higher at surface than in center due to
(A)Skin effect
(B)Corona losses
(C)High current
.
2. Inter conductor distance of high tension lines is ______ than low tension lines
(A) less
(B) more
(C) equal
(D) none
3. Lightening stroke is absorbed by ________ in transmission line
(A) R- phase conductor
(B) Y- phase conductor
(C) B-phase conductor
(D) Earth conductor.
3. For a balanced 3-phase system, which of the following is incorrect,
(A) 3Van- Vab = Vac
(B) 3Vac= Vab + Van
(C 3Van- Vab – Vac=0
5. Which of the following best describes the charging current,
(A) jwCabVab
(B) jwCanVan
(C) jVab/Bc
(D) All above
6.which of the following will not be used while calculating capacitance of transmission line,
(A) GMD
(B) GMR
(C) radius of conductor (D) all of above.
Mark true and false from following.
7. Is this possible that capacitance of transmission line can raise load end voltage ? T
8. Under unbalanced condition, phasor sum of charges on three phase conductors is zero ? F
9. Conductance effect is normally taken as negligible in transmission lines? T
10. Inductance is calculated in series for transmission lines? F
11. Transposition is done to balance the unbalanced 3-phase system? F
12. Charging current is responsible for increasing power factor? F
13. The term “charging currents” is associated with the capacitance of line? T
14. Effect of Inductance in transmission lines is effected by distance between conductors? T
15. Capacitance of transmission line is related to the structure of transformer other than distance from
ground? F
MCQ 4
Choose the best answer
1. Short transmission line model differs from medium line model by ……………… parameter
a. Conductance
b. Inductance
c. capacitance
2. Losses in transmission line are mainly caused by ………………..
a. Resistance
b. Inductance
c. capacitance
3. Voltage regulation for a line having lagging load is taken to be …………………..
a. Positive
b. Negative
c. Zero
4. Power factor of line decreases, line losses ………………..
a. Increases
b. Decreases
c. Remains constant
5. In Regrous solution of transmission line, parameters considered are ………………….
a. Lumped
b. Distributed
c. both
6. In any transmission line which one of the following holds good?
a) AB – CD = 1
b) CD – AB = 1
c) AD – BC = 1
7. Generalized line constant ………. And ……….. are equal
a. A & B
b. B & C
c. A & D
8. The dimensions of of B and C are respectively
a. Ohm and ohms
b. Ohms and siemen
c. Siemen and seimen
9. Length of medium line is up to …………… km
a. 100
b. 150
c. 240
10. Voltage regulation for any transmission line should be ……………….
a. Low
b. High
c. constant