1. An 11 kV, 3-phase transmission line has a resistance of 1.5 Ω and reactance of 4 Ω per phase. The efficiency of the line when supplying the load of 4 MW at 0.8 lagging power factor is nearly

- 99%
- 95%
- 92%
- 90%

2. At what power factor will a lossless line with a reactance of 0.6 pu exhibit zero regulation given that the sending end voltage is 1.0 pu?

- 0.800 lead
- 0.800 lag
- Unity p.f.
- 0.954 lead

3. The time interval needed for a surge to travel to the end of a 600 Km long overhead transmission line is

- 6 s
- 2 s
- 20 ms
- 2 ms

4. An extra high voltage transmission line of length 300 km can be approximated by a lossless line having propagation constant β = 0.00127 rad/km. The percentage ratio of line length to wavelength will nearly be

- 19%
- 24%
- 6%
- 12%

5. Consider a transmission line. The sending end voltage and current are expressed in terms of receiving end voltage and current for the network as

Vs = AV_{R} + BI_{R}

Is = CV_{R}+ DI_{R}

where A, B, C and D are generalized circuit constants.

The condition for symmetry for the network is

- A=D
- A=C
- B=D
- B=C

6. Which of the following is the demerit of a ‘constant voltage transmission system’?

- Increase of short-circuit current of the system
- Availability of steady voltage at all loads at the line terminals
- Possibility of better protection for the line due to possible use of higher terminal reactances
- Improvement of power factor at times of moderate and heavy loads
- Possibility of carrying increased power for a given conductor size in case of long-distance heavy power transmission

7. The square root of the ratio of line impedance and shunt admittance is called the

- surge impedance of the line
- the conductance of the line
- regulation of the line
- none of the above

8. The phenomenon of rising in voltage at the receiving end of the open-circuited or lightly loaded line is called the

- Seeback effect
- Ferranti effect
- Raman effect
- None of the above

9. 310 km line is considered as

- a long line
- a medium line
- a short line
- any of the above

10. Which of the following are the constants of the transmission lines?

- Resistance
- Inductance
- Capacitance
- All of the above