1. When is the Ferranti effect on long over head lines experienced?
a) The lines are lightly loaded
b) The lines are heavily loaded
c) The lines are fully loaded
d) The power factor is unity
2. What is the surge impedance loading of a lossless 400kV, 3 phase, 50Hz overhead line of average of surge impedance of 400 ohms?
a) 400MW
b) 400 X (3)1/2 MW
c) 400 / (3)1/2
d) 400 KW
3. In a 7/30 ACSR conductor why is grease put between steel and aluminium conductors?
a) To reduce corrosion by electrolytic action between zinc (galvanising agent on steel) and aluminium
b) To reduce friction between the strands
c) To reduce leakage of current from the aluminium strands to steel strands
d) To eliminate air pockets
4. A travelling wave due to lightning with an incident voltage V travels through the overhead line of surge impedance of 400 ohms and enters a cable of surge impedance of 40 ohms. What is the voltage entering the cable at the junction
a) V/11
b) 4V/11
c) 2V/11
d) V
5. Bundled Conductors are used for EHV transmission lines primarily for reducing
a) Corona Loss
b) Surge Impedance of the line
c) Voltage drop across the line
d) I2R loss
6. If the traveling wave which is traveling along the loss free line which doesnot undergone any reflection after it reached the end, then the end of the line is:
a) Short circuited
b) Open Circuited
c) Terminated with inductor
d) Terminated in to a resistance which is equal to the Surge Impedance of the line
7. A travelling wave 400/1/50 means crest value of:
a) 400kV with rise time of 1/50 s
b) 400kV with rise time 1 s and fall time 50 s
c) 400kV with rise time 1 miro sec with fall time 50 micro sec
d) 400MV with rise time 1 micro sec and fall time 50 micro sec
8. Consider the following statements:
Surge Impedance loading of a transmission line can be increased by
1. Increasing its voltage level
2. Addition of lumped inductance in parallel
3. Addition of lumped capacitance in series
4. Reducing the length of the line
of the following statements
a) 1 and 3 are correct
b) 1 and 4 are correct
c) 2 and 4 are correct
d) 3 and 4 are correct
9. Transmission efficiency of transmission line increases with the:
a) Decrease in power factor and voltage
b) Increases in power factor and voltage
c) Increase in power factor and decrease in voltage
d) Increase in the voltage but decrease in the power factor
10. Constant power locus of transmission line at particular sending end and receiving end voltage is:
a) A straight line
b) A circle
c) A parabola
d) An ellipse
