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Consider the following statements regarding corona: 1. It causes radio interference. 2. It attenuates lightning surges. 3. It causes power loss. 4. It is more prevalent in the middle conductor of a transmission line employing a flat conductor configuration. Which of the above statements are correct?

Consider the following statements regarding corona: 1. It causes radio interference. 2. It attenuates lightning surges. 3. It causes power loss. 4. It is more prevalent in the middle conductor of a transmission line employing a flat conductor configuration. Which of the above statements are correct? Correct Answer 1, 2, 3 and 4

The phenomenon of ionization of air around the conductor due to which luminous glow with hissing noise is rise is known as the corona effect.

Factors affecting the corona:

  • Supply voltage of transmission lines
  • Operating frequency of transmission lines
  • Spacing between the conductor
  • The radius of the conductor
  • Condition of conductor surface
  • Air Density Factor


Disadvantages of corona discharge:

  • The glow appears across the conductor which shows the power loss occurs on it.
  • The audio noise occurs because of the corona effect which causes the power loss on the conductor.
  • The vibration of the conductor occurs because of the corona effect.
  • The corona effect generates the ozone because of which the conductor becomes corrosive.
  • Corona power loss reduces the efficiency of the line.
  • The radio and TV interference occurs on the line because of the corona effect.
  • Corona effect is more prevalent in the middle conductor in a flat conductor configuration.

 

Important Points:

  • Disruptive voltage is the minimum voltage at which the breakdown of air occurs and corona starts.
  • Visual critical voltage is the minimum voltage at which visible corona begins.
  • One of the advantages of the corona effect is that it reduces the magnitude of lightning and switching surges

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