### MCQs of Basic Principles

Showing 21 to 30 out of 135 Questions
21.
A long overhead transmission line is terminated by its characteristic impedance. Under this operating condition, the ratio of the voltage to the current at different points along the line will
 (a) Progressively increase from the sending-end to the receiving-end (b) Progressively increase from the receiving-end to the sending-end (c) Remain the same at the two ends, but is higher between the two end being maximum at the centre of the line (d) Remain the same at all points
22.
For a transmission line with negligible losses, the lagging reactive power (VAR) delivered at the receiving-end, for a given receiving-end voltage is directly proportional to the
 (a) Square of the line voltage drop (b) Line voltage drop (c) Line inductive reactance (d) LIne capacitive reactance
23.
A three-phase transmission line of negligible resistance and capacitance has an inductive reactance of 100 Ω∕ phase. When the sending-end and receiving-end voltages are maintained at 110 kV, the maximum power that can be transmitted will be
 (a) 121 MW (b) √3 X121 MW (c) 363 MW (d) 363 Kw
24.
The per unit regulation of a short transmission line having a per-unit resistance voltage drop Vr and a per-unit reactance voltage drop of Vx at rated current and power factor cos Θ, is given by
 (a) (Vr+Vx) cosΘ (b) (Vr+Vx) sinΘ (c) Vr cosΘ + Vx sinΘ (d) Vr sinΘ + Vx cosΘ
25.
A 50 Hz 3-phase transmission line of length 100 km has a capacitance of 0.03/π, μF∕ km. It is represented as a π model. The shunt admittance at each end of the transmission line will be
 (a) 150×10–6 ∠90° ℧ (b) 100×10–6 ∠90° ℧ (c) 50×10–6 ∠90° ℧ (d) 6.66×103 ∠90° ℧
26.
In which one of the following models of transmission lines, is the full charging current assumed to flow over half the length of the line only ?
 (a) Equivalent-π (b) Short line (c) Nominal-π (d) Nominal-T
27.
If the receiving-end voltage and current are numerically equal to the corresponding sending-end values, that is, |Vs| = |Vr| and |Is| = |Ir|, then such a line is called
 (a) An infinite line (b) A natural line (c) A tuned line (d) A loss-less line
28.
The values of A, B, C and D constants for a short transmission line are respectively
 (a) Z, 0, 1 and 1 (b) 0, 1, 1 and 1 (c) 1, Z, 0 and 1 (d) 1, 1, Z and 0
29.
The ABCD constants of a 3-phase transmission line are A = D = 0.8∠1° ; B = 170∠85° Ω ; C = 0.002∠90.4° ℧. The sending end voltage is 400 kV. The receiving end voltage under no load condition is
 (a) 400 kV (b) 500 kV (c) 320 kV (d) 417 kV
30.
For a fixed receiving end and sending end voltages in a transmission system, what is the locus of the constant power
 (a) A straight line (b) An ellipse (c) A parabola (d) A circle
Showing 21 to 30 out of 135 Questions