Corona Lighting and Skin Effect MCQ Quiz in मल्याळम - Objective Question with Answer for Corona Lighting and Skin Effect - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക
Last updated on Mar 18, 2025
Latest Corona Lighting and Skin Effect MCQ Objective Questions
Top Corona Lighting and Skin Effect MCQ Objective Questions
Corona Lighting and Skin Effect Question 1:
Lightning arrestors are mostly installed at which of the following places?
Answer (Detailed Solution Below)
Corona Lighting and Skin Effect Question 1 Detailed Solution
Explanation:
Lightning arrestors
- A lightning arrester is connected to protect a piece of equipment from lightning and switching surges.
- Over voltages may cause the burning of insulation of substation equipment if not well protected.
- Lightning is one of the most serious causes of over voltages.
There are various types of lightning arrester construction. They are
- Rod gap LA
- Expulsion type LA
- Valve type LA
- Horn gap LA
- Pellet type LA
- Thyrite type LA
An ideal Lightning Arrester should possess the following characteristics.
- It must not take any current at normal system voltage
- Any transient wave with a voltage peak exceeding the spark over voltage must cause it to break down.
- After the breakdown, it must be capable of carrying the resulting discharge current without any damage to itself and without voltage across it exceeding the breakdown voltage.
- The power frequency current following the breakdown must be interrupted as soon as the transient voltage has fallen below the breakdown value.
- Lightning arrestors are mostly installed at Hydrocarbon plant.
Corona Lighting and Skin Effect Question 2:
Corona loss can be reduced by the use of hollow conductors because
Answer (Detailed Solution Below)
Corona Lighting and Skin Effect Question 2 Detailed Solution
For reducing corona loss, we need to increase the diameter of the conductor.
Making conductors have increased diameter reduces the intensity of the electric field at the surface of the conductor, which reduces corona.
Diameters of conductors can be increased by using hollow conductors and by using steel-cored aluminium conductors (ACSR).
Corona Lighting and Skin Effect Question 3:
In context of corona, which statement is not true?
Answer (Detailed Solution Below)
Corona Lighting and Skin Effect Question 3 Detailed Solution
When an alternating potential difference is applied across two conductors whose spacing is large as compared to their diameters, there is no apparent change in the condition of atmospheric air surrounding the wires if the applied voltage is low.
When the applied voltage exceeds a certain value (critical disruptive voltage), the conductors are surrounded by a faint violet glow called corona.
The phenomenon of the corona is accompanied by a hissing sound, production of ozone, power loss and radio interference. It can take place on all type of transmission lines (short, medium and long).