Power Systems Multiple Choice Questions on “Short Transmission Line – 1”.
1. Which of the following transmission line can be considered as short transmission line?
A. Transmission line of length upto 600 Km
B. Transmission line of length upto 500 Km
C. Transmission line of length upto 200 Km
D. Transmission line of length upto 80 Km
Answer: D
Clarification: The transmission lines having length less than 80 Km are considered as short transmission lines.Their operating voltage is also less than medium and long transmission lines.
2. Which of the following is correct operating voltage range for short transmission lines.
A. Less than 456 KV
B. Less than 132 KV
C. Less than 20 KV
D. Less than 100 KV
Answer: C
Clarification: Transmission lines having length lesser than 80 Km and operating voltage lower than 20 KV fall in the category of short transmission lines.
3. What is the line to earth capacitance value of the short transmission line.
A. Very high
B. Medium
C. Low
D. Negligible
Answer: D
Clarification: Due to smaller distance and lower line voltage, the capacitance effects are extremely small and, so are neglected.
4. Performance of short transmission lines depends on which of the following?
A. Resistance and Capacitance
B. Resistance and Inductance
C. Inductance and Capacitance
D. Resistance, Inductance and Capacitance
Answer: B
Clarification: Due to smaller distance and lower line voltage, the capacitance effects are extremely small and, so are neglected. So, performance of short transmission lines depends only on inductance and resistance of the line.
5. Performance analysis of short transmission line is done __________
A. By symmetrical component analysis method
B. By reactance diagram
C. On per phase basis
D. By neglecting line inductance
Answer: C
Clarification: Performance analysis of balance transmission line is done only. And is done on per phase basis. No symmetrical component method or reactance diagram method is required for performance analysis.
6. What is the value of shunt conductance of short transmission line?
A. Very high
B. Medium
C. Low
D. Negligable
Answer: D
Clarification: In short transmission lines the shunt conductance and shunt capacitance are neglected and so only series resistance and inductance are to be considered.
7. In short transmission line the reciving end voltage may be greater than sending end voltage due to Ferranti effect.
A. True
B. False
Answer: B
Clarification: Ferranti effect is caused due to the high capacitance of the transmission lines. In short transmission lines capacitance effects are negligible. So, Ferranti effect doesn’t happens in short transmission lines.
8. Series inductance and series resistance of short transmission lines are taken as ___________
A. Lumped and Distributed
B. Distributed and Lumped
C. Both Lumped
D. Both Distributed
Answer: C
Clarification: The series inductance and resistance of short transmission lines are taken as lumped. This makes the performance analysis easy.
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