The capacitance of an overhead transmission line increases with1.increase in mutual geometrical mean distance.2.increase in height of conductors above ground.Select the correct answer from the following:

Correct Answer: B - Both 1 and 2 are false

Quick Concept Explanation

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.