Corona discharge, also known as corona, is a phenomenon that occurs when an electrical current flows in a gas and ionizes surrounding air molecules. The word "corona" is spelled /kəˈrəʊnə/ in IPA phonetic transcription, with the first syllable pronounced as "kuh" and the second syllable pronounced as "roh-nuh." The spelling of "discharge" is straightforward, with each syllable pronounced as "dis-charj" /dɪsˈtʃɑrdʒ/ in IPA. Together, the two words create a term that describes a specific type of electrical discharge that can cause damage to electrical equipment.
Corona discharge refers to the phenomenon where an electrical discharge occurs from a conductor or electrode into a nearby gas or fluid medium. It is characterized by the emission of a glowing plasma or ionization aura surrounding the conductor. The discharge appears like a faint, hazy glow, often resembling a halo or crown, hence the name "corona" which means crown in Latin.
Corona discharges can occur at high voltages when the electric field strength around a conductor or sharp object exceeds a critical value. This can lead to ionization of the surrounding air molecules, creating a partially conductive path for the current to flow. The phenomenon is commonly observed in high voltage transmission lines, electrical equipment, and systems where localized electrical stress causes the formation of intense electric fields.
Corona discharges can have both beneficial and detrimental effects. On one hand, they can be used intentionally in applications such as electrostatic precipitators for air purification or for creating ozone in ozone generators. On the other hand, corona discharges can also cause undesirable effects, including energy loss, electromagnetic interference, and the generation of ozone in power lines or electrical equipment.
Understanding and managing corona discharges is crucial in electrical engineering to prevent damage to equipment, maintain system efficiency, and ensure the safe operation of electrical systems. Various techniques, such as optimizing conductor design, using corona rings or shields, and employing insulating materials, are employed to minimize corona effects and preserve system integrity.
The word "corona" comes from the Latin word "corōna", which means "crown" or "garland". It is derived from the Ancient Greek word "korōnē", which also means "crown" or "garland". The term "discharge" originates from the Old French word "deschargier", which means "to unload" or "to dismiss". Therefore, "corona discharge" incorporates the concept of a crown-like phenomenon and the discharge of electrical energy.