Q. 391 A 3-phase transmission line uses 1.24 cm dia. Conductor and these are placed at corners of equivalent triangle of 2 m. The inductance/phase is
A. 12 x 10^-7 H
B. 8.4 x 10^-7 H
C. 7.6 x 10^-6 H
D. 12.5 x 10^-6 H
Ans.: A
Q.392 The generalized constant A, D of transmission line have
A. No dimensions
B. Dimensions of ohm
C. Dimension of mho
D. None of the above
Ans.: A
Q.393 A line which connects distributor to substation is called
A. Source mains
B. Distributors
C. Feeder
D. None of the above
Ans.: C
Q.394 The low lagging power factor results in
A. Large copper losses
B. Poor voltage regulation
C. Reduced handling capacity
D. All of the above
Ans.: D
Q.395 The fault on a power system that gives symmetrical fault current is
A. Line to line fault
B. Three phase short circuit
C. Single line to ground fault
D. none of above
Ans.: B
Q.396 The positive sequence impedance of a feeder is 3 ohm, the negative sequence impedance will be
A. 3 ohm
B. 1 ohm
C. 9 ohm
D. 6 ohm
Ans.: A
Q.397 An isolator is designed to open at
A. Full load
B. Normal condition
C. No load
D. None of the above
Ans.: C
Q.398 PLCC is used in substations which do not include among following
A. Wave trap
B. Coupling capacitor
C. Power line conductor
D. Capacitor bank
Ans.: D
Q.399 The surge diverter protects substation equipment against
A. Direct lighting stroke
B. Travelling waves
C. Both a and B
D. None of the above
Ans.: C
Q.400 In capacitance grading of cable, the dielectric of highest permittivity is
A. Near the core
B. In the middle
C. Farthest away from core
D. none of the above
Ans.: C
Q.401 digital instrument has impedance of the order of
A. MΩ
B. kΩ
C. Ω
D. mΩ
Ans.:A
Q.402 LVDT has following advantages-
A. Infinite resolution, high sensitivity
B. Low hysteresis, high repeatability
C. Passive transducer
D. Both a and B
Ans.: D
Q.403 The acceleration in main line traction system is approximately-
A. 0.5- 1 kmphps
B. 1.5-4 kmphps
C. 6-8 kmphps
D. none of the above
Ans.: C
Q,404 Regenerative braking is possible in Traction system
A. Urban
B. Suburban
C. Mainline
D. None of the above
Ans.: C
Q.405 The most accurate method for HVAC and HVDC measurement is
A. Electrostatic voltmeter
B. Sphere gap method
C. Resistance divider method
D. Capacitance diverter method
Ans.: B