Electrician Red Seal · Question
While performing routine maintenance on a 25 kV overhead power system, an apprentice notices significant corona discharge around a damaged insulator. What is the primary cause of this phenomenon?
Corona discharge occurs when the electric field strength at the surface of a conductor or insulator exceeds the dielectric strength of the surrounding air, ioni
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Question: While performing routine maintenance on a 25 kV overhead power system, an apprentice notices significant corona discharge around a damaged insulator. What is the primary cause of this phenomenon?
Answer options:
- Excessive magnetic fields around the conductor. ✅ High electric field strength ionizing the air near the conductor.
- Overcurrent in the transmission line.
- Low ambient temperature causing condensation on the insulator.
Correct answer: High electric field strength ionizing the air near the conductor.
Explanation: Corona discharge occurs when the electric field strength at the surface of a conductor or insulator exceeds the dielectric strength of the surrounding air, ionizing the air and creating a visible glow, often with an audible hiss.
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