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The Value of Inspection for Electrical Utilities

Ofil has solutions that assist electrical utilities manage their infrastructure. Our solutions aim at reducing maintenance cost and extending the operational lifetime of components that are exposed to the dramatical changes in climate, pollution levels and increased power consumption.   The accelerated aging of overhead line components and mainly of insulators, motivated manufacturers like Ofil to develop new technologies, new material, new sensors, new maintenance management approaches and new testing equipment. All of these rely on Information and collections of big data from multiple sources in various formats. Seeing corona partial discharge, correlating it to factors such as pollutions, precipitation, design and linking to past performance and faults is an example of information that utilities seek.


Inspection with DayCor® handheld corona cameras and findings

Information gathered by Ofil’ cameras helps utilities rely on their OWN experience, and schedule their OWN maintenance activities. Often, components or structures that were guaranteed to be fit for installation in a certain location, e.g., selecting recommended insulators type for coastal areas or deserts or mountains, failed to perform as expected and led to unexpected outages. To find out which component is failing or what is the root cause involve lengthy investigations, but these can be so much shorter and efficient if corona cameras are used.

How? Corona will always exist in locations where a local electrical field surpasses a certain threshold value, triggering ionization processes and avalanches of electrons. As such, corona will be seen on insulators that lose their hydrophobicity, on corroded end fittings, on insulators whose corona rings do not perform, on conductors that have broken strands or unappropriated radii, etc. One session of inspection with a corona camera reveals instantaneously abnormalities. Repeated sessions of inspection provide trending and understanding of the condition of the grid throughout the year, and whether the correct components were installed. A stationary corona camera can monitor 24/7 the condition of a critical component and alert in real time at the early stages of failures.


The absence of corona rings is immediately noticed by a DayCor® and serves as early warning

Inspection changes the way utilities manage their maintenance teams. On the one hand, the option to perform inspection while lines are energized without neither planned outages nor overloading simplifies maintenance. On the other hand, decreasing time-based blind replacement of condition based reduces the need to spend capital without any reason. Condition based maintenance relies on reliable sources of information such as Ofil corona cameras. Systems that are corona free and free of thermal hot spots, can be kept despite their age.

Interval of Insulators washing, a costly process, can be correlated to corona. Under humid conditions layers of pollution become conductive, affecting the leakage current distance. Seeing the discharge and trending throughout the changing seasons is a valuable data source for assets managers that affect cost of operation and of components health.


Effective and safe non-destructive remote testing UV detecting solutions turn out to be cost effective. Corona signals are eye catchers and as soon as they are detected they cannot be ignored. Behind each signal hides an issue that occasionally means “need repair”. Yet, in most cases, UV radiation serves as early warning signs, and at that stage faults can be repaired at low cost. 

HV laboratories investigate faults’ chronology. Setting up the lab is costly and time consuming. Using corona cameras during the first phase of research can lead to a direction where and what to investigate. Furthermore, PD measuring equipment cannot pinpoint and show the critical points of emission. Corona cameras fill it this gap, instantaneously and extremely accurately.  

Rotating machine workshops substitute the pitch black dark room during their investigation with a daytime corona camera that allows them to get to improved results under regular light, and helps them mark findings that were spotted by the camera. 

During commissioning, contractors use the camera to ascertain that their work was fulfilled correctly. 

Manufacturers of components use the camera to show customers that their components are corona free. 

Utilities use the camera to avoid litigations due to corona audio noise. 

And more.


  • Ofil DayCor® range of solutions include:
    • Handheld corona cameras for foot patrol and inhouse testing
    • Block cameras for aerial inspections on helicopters
    • Corona cameras for UAVs with integration solutions
    • Cameras for driven inspections in combination with additional technologies
    • Stationary standalone corona cameras for 24/7 scanning
    • Encapsulated multi sensors stabilized gimbaled solutions for various types of helicopters
  • All cameras provide reliable information about existing UVc discharges emitted by corona.
  • The outcome data is visual, in real time without image processing, repeatable and accurate.
  • Our UV cameras are calibration free, since they are not categorized as measuring equipment, and therefore fit for continuous ongoing operation.
  • Ofil DayCor® systems are valuable NDT equipment capable of remote detection and pinpointing of UVc radiation
  • HD recording of corona events on faulty components serves the need for documentation, reporting and prediction.
  • All products are bundled with excellent customer service.

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