4-Way Inspection Services is currently inspecting various distribution lines and sub-stations in and around the Edmonton, Alberta area with the use of a Corona Camera. With the use of this technology, our factory trained technicians can inspect our customers high voltage equipment and prevent costly, unexpected power failures and/or outages.
What Is Corona?
Corona results from ionized air or ozone (O3) caused by damaged insulation, contamination and faulty design. Ozone will conduct current and can form a direct path to ground, resulting in catastrophic results, especially in enclosed switchgear. Corona also produces nitrogen exides which form nitric acid when combined with moisture. This acid further destroys the insulating material as well as metal components causing possible thermal problems and highly unpredictable situations.
Where Can Corona Be Detected?
Corona is a serious issue that can occur in switchgear 2000V or greater. In metal clad switchgear, the most serious result can be a flashover causing enormous damage and personal injury. With completing a corona inspection, corona, tracking and arcing can be detected and remedied before serious results occur.
High voltage power distribution lines as well as high voltage substations are also very susceptible to the presence of Corona.
The integrity of conductors' conditions, buswork and hardware conditions, porcelain post, pin as well as bell insulators conditions, polymer insulators' conditions, switch gears, transformers etc., can be determined with the completion of a corona inspection.
Inspection for corona sources is important throughout the life time of substations, and in particular during commissioning.
The corona inspection pinpoints sources of corona partial discharge and identifies faulty components in deteriorating stages.
What Deficiencies Can Be Identified By Completing A Corona Inspection?
- 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.
- Corona on capacitors
Why Conduct A Corona Inspection?
The ability to easily detect corona and arcing sources and pinpoint their locations can save utilities considerable amounts of money. The information obtained by Corona inspection leads to:
- Prioritizing maintenance tasks
- Avoiding unnecessary line washings
- Concentrating on the faulty hardware