A. corona effect
B. skin effect
C. unsymmetrical fault
D. all of the above
Answer: B. skin effect
Explanation:
Skin effect is the tendency of an alternating electric current (AC) to become distributed within a conductor such that the current density is largest near the surface of the conductor and decreases exponentially with greater depths in the conductor. At high frequencies, the skin depth becomes much smaller.
Skin effect, in electricity, the tendency of alternating high-frequency currents to crowd toward the surface of a conducting material.
This phenomenon restricts the current to a small part of the total cross-sectional area and so has the effect of increasing the resistance of the conductor.
Accumulation of current on the surface of the conductor is called skin effect. Due to skin effect the effective area of current flowing path is reduced.
Where,
f = frequency
µr = relative permeability
σ = conductivity
Skin effect depends on
1. Supply frequency
2. Relative permissibility
3. Conductivity σ
4. Size of the conductor
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