Power Systems Quiz on “Geometric Mean Distance and Geometric Mean Radius – 2”.
1. The power transmission capability of bipolar lines is approximately ____________
A. same as that of 3-ph single circuit line
B. same as that of 3-ph double circuit line
C. twice to that of 3-ph single circuit line
D. half to that of 3-ph single circuit line
Answer: A
Clarification: Power transmission by bipolar dc line is same as that three phase single line transmission.
2. HVDC system has charging current but no skin effect while transferring the power through it.
A. True
B. False
Answer: B
Clarification: Skin effect as well as the charging effect, both are absent in dc transmission system.
3. As depicted in the figure, the power will be transferred in the system from A to B by a HVDC link as shown in the figure. The voltages are indicated in the figure and I >0, then _______
A. Vab<0, Vcd<0, Vab>Vcd
B. Vab<0, Vcd>0, Vab<Vcd
C. Vab>0, Vcd<0, Vab>Vcd
D. Vab>0, Vcd>0, Vab>Vcd
Answer: D
Clarification: The given situation is such as the current is more than zero, so a positive current will flow from higher voltage to lower voltage.
4. As depicted in the figure, the power is transferred in the system from B to A by a HVDC link as shown in the figure. The voltages are indicated in the figure and I <0, then ______
A. Vab<0, Vcd<0, Vab>Vcd
B. Vab<0, Vcd>0, Vab<Vcd
C. Vab>0, Vcd>0, Vab<Vcd
D. Vab>0, Vcd>0, Vab>Vcd
Answer: C
Clarification: The given situation is such as the current is less than zero, so a positive current will flow from higher voltage to lower voltage i.e. from cd to ab.
5. A dc line carries as compared to ac line _____________
A. more power
B. less power
C. same power
D. can’t be decided
Answer: A
Clarification: A dc line carries more power as compared to ac line.
6. Back to back HVDC is used to ___________
A. increase the transmission capability
B. decrease line losses
C. provide a stable connection
D. reduce the voltage drop
Answer: C
Clarification: Back to Back connection in HVDC will provide a stable connection.
7. HVDC transmission would require which of the following equipment’s?
(i) Pulse converter
(ii) AC filter
(iii) DC filter
(iv) DC generator
A. (i)
B. (i), (ii)
C. (ii), (iv)
D. (i), (iii)
Answer: A
Clarification: Only pulse converter is needed by HVDC transmission system.
8. As compared with the HVAC lines, dc transmission system is free from ___________
A. inductance
B. capacitance
C. phase displacement
D. all of the mentioned
Answer: D
Clarification: All the factors which involve frequency will be absent in dc system as in f= 0 in dc.
9. Mostly the high voltage transmission is provided by overhead lines due to _____________
A. low cost
B. low losses
C. easy installation
D. all of the mentioned
Answer: A
Clarification: Due to economic criteria, the high voltage transmission is done by overhead lines.
10. Consider the below statements and choose the most appropriate.
(i) Guy wire is galvanised.
(ii) Guy wire should possess high conductivity.
(iii) At installation it makes an angle of 40-60 degrees with earth.
A. (i), (ii) and (iii) are true
B. Only (i) and (ii) are true
C. (ii) and (iii) are true
D. (i) and (iii) are true
Answer: A
Clarification: All the statements about the guy wire are true.