The capacitance of an overhead transmission line increases with
1. increase in mutual geometrical mean distance.
2. increase in height of conductors above ground.
Select the correct answer from the following:
Answer & step-by-step solution
Capacitance is larger when conductors/electrodes are effectively closer. In overhead lines, larger phase spacing weakens electric coupling between phases. Key relation: Simple line: C ∝ 1/ln(D/r). Single conductor to ground (image model): C ∝ 1/ln(2h/r). Therefore dC/dD<0 and dC/dh<0.
Exam focus: Inductance generally increases with spacing; capacitance generally decreases with spacing. Common trap: Mixing up the spacing trends of line inductance and capacitance.
Statement-wise Verification
- Statement 1 - Incorrect.
increase in mutual geometrical mean distance.
For a simple overhead line, capacitance varies inversely with ln(D/r); increasing separation D increases the logarithmic denominator and reduces capacitance. - Statement 2 - Incorrect.
increase in height of conductors above ground.
A conductor farther from ground has a larger electrostatic path/logarithmic denominator to its image, so its capacitance to ground decreases rather than increases.
Core Concept
Capacitance is larger when conductors/electrodes are effectively closer. In overhead lines, larger phase spacing weakens electric coupling between phases. Earth can be handled by the method of images; increasing height reduces the earth’s capacitive influence.
Formula / Key Relationship
Simple line: C ∝ 1/ln(D/r). Single conductor to ground (image model): C ∝ 1/ln(2h/r). Therefore dC/dD<0 and dC/dh<0.
Step-by-Step Check
Both standard logarithmic capacitance relations decrease as D or h increases. Therefore option B (“Both 1 and 2 are false”) is correct.
Why the Other Options Are Wrong
Option A is incorrect because it includes incorrect statement(s) 1, 2. Option C is incorrect because it includes incorrect statement(s) 1. Option D is incorrect because it includes incorrect statement(s) 2.
Answer-Key Verification Note
The uploaded provisional key marks A . After independent technical verification, the defensible answer is B . This discrepancy is stated explicitly rather than silently copying the provisional key.
Exam Shortcut / Approach
Inductance generally increases with spacing; capacitance generally decreases with spacing.
Common Mistake
Mixing up the spacing trends of line inductance and capacitance.
Quick Revision
Effect of Spacing and Ground on Capacitance is linked with Line Capacitance, Transmission Lines and Power Systems. Inductance generally increases with spacing; capacitance generally decreases with spacing.
ओवरहेड पारेषण लाइन की धारिता बढ़ती है
1. परस्पर ज्यामितीय माध्य दूरी (GMD) बढ़ने से।
2. भूमि से चालकों की ऊँचाई बढ़ने से।
निम्नलिखित में से सही उत्तर चुनिए:
उत्तर और चरणबद्ध हल
B — दोनों असत्य। C ∝ 1/ln(D/r) और भूमि के लिए C ∝ 1/ln(2h/r); इसलिए GMD (D) या ऊँचाई (h) बढ़ने पर धारिता घटती है। याद रखें: दूरी बढ़ने पर प्रेरकत्व बढ़ता है, धारिता घटती है।
विस्तृत हल (मूल भाषा में)
Statement-wise Verification
- Statement 1 - Incorrect.
increase in mutual geometrical mean distance.
For a simple overhead line, capacitance varies inversely with ln(D/r); increasing separation D increases the logarithmic denominator and reduces capacitance. - Statement 2 - Incorrect.
increase in height of conductors above ground.
A conductor farther from ground has a larger electrostatic path/logarithmic denominator to its image, so its capacitance to ground decreases rather than increases.
Core Concept
Capacitance is larger when conductors/electrodes are effectively closer. In overhead lines, larger phase spacing weakens electric coupling between phases. Earth can be handled by the method of images; increasing height reduces the earth’s capacitive influence.
Formula / Key Relationship
Simple line: C ∝ 1/ln(D/r). Single conductor to ground (image model): C ∝ 1/ln(2h/r). Therefore dC/dD<0 and dC/dh<0.
Step-by-Step Check
Both standard logarithmic capacitance relations decrease as D or h increases. Therefore option B (“Both 1 and 2 are false”) is correct.
Why the Other Options Are Wrong
Option A is incorrect because it includes incorrect statement(s) 1, 2. Option C is incorrect because it includes incorrect statement(s) 1. Option D is incorrect because it includes incorrect statement(s) 2.
Answer-Key Verification Note
The uploaded provisional key marks A . After independent technical verification, the defensible answer is B . This discrepancy is stated explicitly rather than silently copying the provisional key.
Exam Shortcut / Approach
Inductance generally increases with spacing; capacitance generally decreases with spacing.
Common Mistake
Mixing up the spacing trends of line inductance and capacitance.
Quick Revision
Effect of Spacing and Ground on Capacitance is linked with Line Capacitance, Transmission Lines and Power Systems. Inductance generally increases with spacing; capacitance generally decreases with spacing.
ઓવરહેડ પારેષણ લાઇનની ધારિતા વધે છે
1. પરસ્પર ભૌમિતિક મધ્યક અંતર (GMD) વધવાથી.
2. જમીનથી વાહકોની ઊંચાઈ વધવાથી.
નીચેનામાંથી સાચો જવાબ પસંદ કરો:
જવાબ અને પગલાવાર ઉકેલ
B — બંને ખોટાં. C ∝ 1/ln(D/r) અને જમીન માટે C ∝ 1/ln(2h/r); તેથી GMD (D) કે ઊંચાઈ (h) વધતાં ધારિતા ઘટે છે. યાદ રાખો: અંતર વધતાં પ્રેરકત્વ વધે છે, ધારિતા ઘટે છે.
વિગતવાર ઉકેલ (મૂળ ભાષામાં)
Statement-wise Verification
- Statement 1 - Incorrect.
increase in mutual geometrical mean distance.
For a simple overhead line, capacitance varies inversely with ln(D/r); increasing separation D increases the logarithmic denominator and reduces capacitance. - Statement 2 - Incorrect.
increase in height of conductors above ground.
A conductor farther from ground has a larger electrostatic path/logarithmic denominator to its image, so its capacitance to ground decreases rather than increases.
Core Concept
Capacitance is larger when conductors/electrodes are effectively closer. In overhead lines, larger phase spacing weakens electric coupling between phases. Earth can be handled by the method of images; increasing height reduces the earth’s capacitive influence.
Formula / Key Relationship
Simple line: C ∝ 1/ln(D/r). Single conductor to ground (image model): C ∝ 1/ln(2h/r). Therefore dC/dD<0 and dC/dh<0.
Step-by-Step Check
Both standard logarithmic capacitance relations decrease as D or h increases. Therefore option B (“Both 1 and 2 are false”) is correct.
Why the Other Options Are Wrong
Option A is incorrect because it includes incorrect statement(s) 1, 2. Option C is incorrect because it includes incorrect statement(s) 1. Option D is incorrect because it includes incorrect statement(s) 2.
Answer-Key Verification Note
The uploaded provisional key marks A . After independent technical verification, the defensible answer is B . This discrepancy is stated explicitly rather than silently copying the provisional key.
Exam Shortcut / Approach
Inductance generally increases with spacing; capacitance generally decreases with spacing.
Common Mistake
Mixing up the spacing trends of line inductance and capacitance.
Quick Revision
Effect of Spacing and Ground on Capacitance is linked with Line Capacitance, Transmission Lines and Power Systems. Inductance generally increases with spacing; capacitance generally decreases with spacing.