Corona Discharge - Problems Caused By Corona Discharges

Problems Caused By Corona Discharges

Coronas can generate audible and radio-frequency noise, particularly near electric power transmission lines. They also represent a power loss, and their action on atmospheric particulates, along with associated ozone and NOx production, can also be disadvantageous to human health where power lines run through built-up areas. Therefore, power transmission equipment is designed to minimise the formation of corona discharge.

Corona discharge is generally undesirable in:

• Electric power transmission, where it causes:
  • Power loss
  • Audible noise
  • Electromagnetic interference
  • Purple glow
  • Ozone production
  • Insulation damage
• Electrical components such as transformers, capacitors, electric motors and generators. Corona progressively damages the insulation inside these devices, leading to premature equipment failure. One form of attack is ozone cracking of elastomer items like O-rings.
• Situations where high voltages are in use, but ozone production is to be minimised
• Static electricity discharge

Coronas can be suppressed by corona rings, toroidal devices that serve to spread the electric field over larger area and decrease the field gradient below the corona threshold.