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keywords: Electrical UTILITIES, Testing Power Grid, Maintenance, Distribution Transmission, Sustation Generation UV imaging, NDT Monitoring


Mines, refineries, data centers and heavy industries that operate in a high voltage environment, or get high voltage supply that needs to be transformed into lower voltages encounter issues related to partial discharge corona and arcing.

Pollution, typical to mines, refineries and manufacturing plants, combined with high voltage and humidity act as a greenhouse for partial discharges that deteriorates to full discharge.

Typically, those companies are heavy consumers of electricity and must have steady, reliable on-going power supply with very low tolerance to outages. For mines outages can cost in human life. Their asset management will always strive to maximize their equipment investment return by maximizing performance and minimizing cost over the entire equipment life cycle. As a result their will need:

  • The best way to monitor and maintain
  • The best way to expand their system to meet future needs
  • The best way to provide system performance

Read what our customers have to say: "We are a remote mine located in the northwestern portion of the country, where we fly into site. We have been leasing the services of a contracting company who provides us condition monitoring and cleaning of our 60+ underground 5kV & 15kV substations (and associated equipment). We decided to take on the ultraviolet inspection portion on our own to complement the IR & UE equipment we already have. This will reduce our costs because we decided to curtail our major cleaning to a bi-annual visit but we will still conduct our own annual UV, IR & UE inspections. Ofil's DayCor® UVollé handheld camera was selected. We have two 115kV outdoor substations on surface, but underground are where the major problems exist because of high humidity and severe diesel particulate & dust issues."

Ofil's corona cameras assist manufacturers achieve these goals by providing reliable NDT and non-destructive monitoring equipment. A combination of UV technology with other complementary technologies can assist achieving the required performance of their systems.


  • DayCor® Luminar
  • DayCor® Superb
  • UVollé
  • DayCor® SCALAR

Why look for corona?

Corona is involved with electrical and mechanical failures. It is a degrading agent and an environmental interferer. Corona is both an active agent and a signal of existing failures. As an active agent it constitutes the main ageing phenomena of insulators. Corona discharges on polymer surfaces have low intensity and reduced heat. But, when corona discharge, which is in close contact with surfaces, lasts for long periods it results in changes to the hydrophobicity, roughness profile and oxidation rate. Loss of hydrophobicity leads to dry band arcs between non-uniform wet layers and is the key ageing phenomena. It is therefore so important to use a diagnosis and monitoring technique that reveal failures that are still in their reversible stage.

Corona is known as creating audio noise, radio and TV interferences. Communication can be distorted by corona. Audio noise is always a nuisance.

Corona is an indicator of:

  • Possible faults
  • Improper installations
  • Shorted bells
  • Air Gap
  • Loose hardware
  • Contamination
  • Corrosion or erosion
  • Broken strands on conductors
  • Bad ground connections

Dyacor® is used to monitor/inspect

  • Electrical cabinets
  • Insulators
  • Motors
  • Primary power sources
  • Switchgear
  • Transformers
traffo switchgear A UViGrapher in action Transmission lines