Daily Concept Booster Electrical Engineering: PROXIMITY EFFECT

Table of Contents

PROXIMITY EFFECT

Definition

The alternating magnetic flux produced in the conductor due to the current flowing through the neighboring conductor gives rise to the circulating current which increases the resistance of the conductor. This phenomenon is called the proximity effect.

Proximity Effect in Transmission line

• The proximity is more in the case of power cable and underground line where the distance between the conductor is small.
• This effect is negligible in the case of overhead transmission lines because the distance between the conductors is large.

Proximity effect in DC Transmission

The proximity effect is absent in the case of DC transmission because the frequency of DC transmission is zero.

Factors affecting Proximity Effect

The proximity effect depends upon the size of the conductor, spacing between the conductor, frequency and permeability of the conductor material.

This effect increases with an increase in frequency.
The more the diameter of the conductor, the more will be this effect.
This effect also depends on the material of the conductor. If the material is of ferromagnetic nature, the proximity effect will be more.
The proximity effect is more in the case of solid conductors. This is the reason, stranded or ACSR conductors are used to reducing this effect.

Example

Q1. Proximity effect is more in case of
(A) Overhead line
(B) Power cable
(C) DC transmission
(D) None of the above

Ans.(B)
Explanation:
The alternating magnetic flux produced in the conductor due to the current flowing through the neighbouring conductor gives rise to the circulating current which increases the resistance of the conductor. This phenomenon is called the proximity effect.
• The proximity is more in the case of power cable and underground line where the distance between the conductor is small.

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