Corona Surveys
Service
High Voltage Solution (HVS) offer the following Corona surveys:
- Aerial Surveys of transmission assets (Using Helicopter)
- High and medium voltage substations / Transmission & Distribution assets.
- Switchgear
Advantages
Inspection for corona sources is important throughout the life time of any substation / distribution or transmission, and in particular during commissioning of these same assets.
Daytime corona cameras enable pinpointing sources of corona partial discharge and designate thereby faulty components and components in deteriorating stages.
Using (HVS) systems in Substations / Transmission & Distribution can prevent outages and flashovers and reduces significantly the maintenance costs.
CORONA CAMERAS CAN NOTE:
- Degradation of Polymer insulators
- Contamination - coastal salt; industrial vapours 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…
- Loose hardware such as: spacers, slices, clamps etc.
- Corona on capacitors
Difference between IR & UV
| InfraRed | UltraViolet (Corona) |
|---|---|
| Detects Δ - Hot Spots – Not Corona! | Detects Corona |
| Current Dependent | Voltage dependent (e-field) |
| Heavy Line Loading is needed | No line loading needed |
| Solar radiation and hot environment can mislead | All lighting & weather conditions |
| Detection occurs usually at progressive stage of degradation | Detection at Earlier of Degradation, (i.e. Commissioning) |
For further references regarding Corona discharge please visit the following independent web sites:
https://www.youtube.com/user/HighVoltageSolution
https://www.maintenanceworld.com/Articles/ninedorfd/coronatesting.html
http://reliabilityweb.com/index.php/articles/viewing_corona_in_the_daytime/
http://www.daycor.com/BPA users DayCor to pinpoint faulty transmission line insulators.pdf