Power Systems online test on “Medium Transmission Line – 2”.
1. In medium transmission lines capacitive current is ________________
A. Less than short transmission lines
B. Equal to short transmission lines
C. More than short transmission lines
D. More than long transmission lines
Answer: C
Clarification: Line to Earth capacitance of medium transmission line is more than that in short transmission line and less than that in long transmission line. Because of this the charging current of medium transmission line is more than that in short transmission line and less than that in long transmission line.
2. In actual the capacitance of line is ____________
A. More at receiving end
B. More at sending end
C. Uniformly distributed over entire length
D. More in middle of sending end and receiving end
Answer: C
Clarification: Actually the capacitance of line is uniformly distributed over its entire length. To make calculations simple the capacitance of the system is assumed to be divided up and lumped in the form of capacitors shunted across the line at one or more points.
3. Charging current in medium transmission line is _________________
A. Maximum at receiving end
B. Maximum at sending end
C. More in between sending and receiving end
D. Equal throughout the line
Answer: A
Clarification: The magnitude of capacitive current flowing at any point along the line is that required to charge the section of the line between the given point and receiving end. Hence, it has maximum value at the sending in and diminished at practically uniform rate down to zero at the receiving end.
4. In end condenser method of solution of medium transmission line, capacitance of the line is assumed to be _____________
A. Distributed uniformly from sending end to receiving end
B. Lumped at the load end
C. Lumped at the generation end
D. Lumped at middle of generation and load end
Answer: B
Clarification: In end condenser method the capacitance of the line is assumed to be lumped at the load end. This method overestimates the effect of capacitance.
5. In nominal-T method of solution of medium transmission line, capacitance is assumed to be __________
A. Distributed uniformly from sending end to receiving end
B. Lumped at the load end
C. Lumped at the generation end
D. Lumped at middle of generation and load end
Answer: D
Clarification: In nominal- T method or middle condenser method of analysis of medium transmission line the whole of the line capacitance is assumed to be concentrated at the middle point of the line and half the line resistance and reactance to be lamp on either side.
6. In nominal-π method of solution of medium transmission line, capacitance is assumed to be:
A. Distributed uniformly from sending end to receiving end
B. Divided into two halves
C. Lumped at the generation end
D. Lumped at middle of generation and load end
Answer: B
Clarification: In nominal-π method of solution of medium transmission line the capacitance of each line conductor is assumed to be divided into two halves. One half being shunted between line conductor and neutral at the receiving in and other half at the sending end.
7. Medium transmission line operates below voltage level of 20 KV.
A. True
B. False
Answer: B
Clarification: The voltage limit of 20 KV is for short transmission lines. Medium transmission lines can operate for voltage more than 20 KV.
8. Which of the following is not a method for solution of medium transmission line?
A. End condenser method
B. Nominal-T method
C. Nominal-π method
D. Nominal-H method
Answer: D
Clarification: Actual method used for solution of medium transmission lines are end condenser method, nominal-T method and nominal π method.
9. In a nominal-π method the resistance of line is assumed to be __________
A. Distributed uniformly from sending end to receiving end
B. Divided into two halves
C. Lumped at the generation end
D. Lumped at middle of the line
Answer: D
Clarification: In nominal-π method the capacitance of each line conductor is assumed to be divided into two halves and the resistance of the line is assumed to be lumped in between them at the middle of the line.
10. In nominal-T method of solution of medium transmission line, resistance and inductive reactance of the line is divided into two half’s.
A. True
B. False
Answer: A
Clarification: In nominal-T method of solution of medium transmission line, the whole of the line capacitance is assumed to be concentrated at the middle point of the line and half the line resistance and reactance to be lumped on either side of it.
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