Corona has the disadvantage of

Question

Examoogle · Accepted Answer

Option D: All of above

Explanation & Concepts:
Corona is an electrical discharge brought on by the ionization of a fluid such as air surrounding a conductor that is electrically charged. This phenomenon leads to significant power losses, interference with nearby communication systems due to electromagnetic radiation, and the generation of harmonic currents in the power line.

Working Principle: When the potential gradient at the surface of a conductor exceeds the dielectric strength of the surrounding air (breakdown voltage), ionization occurs. This creates a localized discharge current, producing light, heat, noise, and ozone, which manifests as energy dissipation known as corona loss. The non-linear nature of this discharge causes the formation of harmonics in the current waveform.

Key Formulas: $V_c = g_0 \delta m_0 r \ln(\frac{d}{r})$ — Critical disruptive voltage, where $g_0$ is the breakdown strength of air.; $P_c = \frac{241}{\delta} (f + 25) \sqrt{\frac{r}{d}} (V - V_c)^2 	imes 10^{-5}$ — Empirical formula for power loss in kW/km/phase.

Key Points: Corona is most pronounced during stormy or humid weather due to reduced dielectric strength of air.; It causes a hissing sound, ozone gas formation, and a faint violet glow.; Bundled conductors are used to increase the effective radius and reduce corona effects.; It generates non-sinusoidal currents, thus introducing harmonics into the transmission system.

Advantages: Reduces surge voltages on the line due to dissipation of energy; Warns maintenance personnel of insulation breakdown levels

Disadvantages: Significant energy loss reduces overall transmission efficiency; Electromagnetic interference disrupts telecommunication lines; Harmonic distortions interfere with protective relaying equipment; Chemical ozone formation causes corrosion of hardware

Additional Info: The phenomenon is dependent on the line voltage, conductor surface condition, and weather.. Option B is correct because the electromagnetic energy radiated by the corona discharge creates significant noise in high-frequency radio and telecommunication bands.

Answer: D is correct — Corona discharge negatively impacts power systems through energy dissipation, electromagnetic interference with communication, and the induction of harmonics.

Exam Tip: Always remember that bundling conductors is the primary practical method to reduce both corona loss and the inductance of the transmission line.

Examoogle · Answer

Option A: Power loss

Examoogle · Answer

Option B: Interference with communication lines

Examoogle · Answer

Option C: Introducing the harmonics

Correct Answer

Discussion (0)

Correct Answer

Related Questions

Discussion (0)