Corona is a phenomenon associated with transmission lines. It is created under conditions where localized electric field exceeds a certain critical value (4.5kV/cm). Corona occurs on all types of transmission lines, and it becomes more noticeable at higher voltages and higher altitudes. Utilities try to reduce the amount of corona because in addition to audio noise, radio and TV interferences and power loss corona will damage the grid components.
Worldwide electric utilities are using Ofil’s DayCor® cameras to inspect routinely their overhead transmission lines. EPRI, the American Electrical Research Institute and STRI – a Swedish consulting company and accredited high voltage laboratory have published guides to corona and arcing inspection of overhead transmission lines, based upon Ofil’s DayCor®cameras
Using DayCor® cameras will assist control:
- Degradation of Polymer insulators
- Contamination – coastal salt; industrial vapors and dusts; cement dust; highway road-salt; tire dust and car emissions; agricultural dusts and fertilizers
- Cracked porcelain insulators
- Rusted cement and metal caps & pins on porcelain insulators.
- RFI, TVI and audio noise sources lead to customer complaints
- Wrong design and improper installation, that may lead to mechanical and electrical failure, of: hardware such as corona ring, conductors ADSS etc…
- Shorted bells
- Loose hardware such as: spacers, slices, clamps etc.
Transmission Lines Characteritics
- Long inspection lines
- Inspection of remote objects
- Topographic barriers