Professional Answer: Understanding the disruptive critical voltage is essential for designing efficient and reliable overhead transmission lines. When the operating voltage of a line surpasses this critical value, the resulting corona discharge causes several adverse effects:

1. Energy Loss: Corona discharge dissipates electrical energy in the form of light, sound, and heat, leading to power loss and reduced transmission efficiency.

2. Radio Interference: The ionization process generates high-frequency noise that can interfere with radio and television signals.

3. Conductor Degradation: The ozone produced during corona can chemically react with and corrode the conductor materials over time.

To mitigate these issues, engineers must design power lines with a disruptive critical voltage higher than the line's operating voltage. This is typically achieved by using larger-diameter conductors or bundle conductors, which increase the effective radius and reduce the electric field gradient at the conductor surface.