US 1.888.950.5557 | CN 86.1580.215.4221


US 1.888.950.5557 | CN 86.1580.215.4221

The presence of corona activity is one of the best indicators of defects

Corona discharge is the starting point of surface degradation processes. Corona can hit any medium/high voltage apparatus: transformers, bushings, capacitors, insulators, switchgear, conductors, cables, motors, spacers, switch cabinets, and more and affect reliability.  

Material degradation due to corona discharge influences the electrical and mechanical performance of power grids. It has been proven that the presence of corona activity is one of the best indicators of defective NCIs. Moreover, corona can lead inspectors to the exact location of the fault so that corrective action can be taken, mainly if detected on time when faults can still be fixed.   

Research conducted in the USA (Lawrence Berkeley National laboratory) estimated that power outages cost the U.S economy $80 billion annually. This figure calls for utilities to prevent service interruptions and concentrate on the reliability of their assets.  Electric utilities strive to provide reliable services at reasonable costs. Ofil can help with that because corona detection is absolutely a reliability driven act that entails a reasonable investment cost. While both utilities and their customers benefit from the outcome of corona detection, the economic benefit attained outweighs the cost of our corona detection systems.

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NDT – Effective Preventive & Predictive Maintenance Solution

Corona is a Major Concern

Corona PD on electrical grid elements is a concern because it causes:

  • Degradation of insulation
  • Physical damage to components 
  • Radio interference
  • Audio noise 
  • Emission of UV, Ozon and other abrasive acids 
  • Lead to arc flash

Corona indicates

  • Design faults 
  • Improper installation
  • Contamination
  • Insulation problems
  • Imminent flashover or tripping 
  • Safety risks

Benefits & Advantages to Electrical Utilities?

  • Safety – Testing is performed during daytime 
  • Information –  Valuable pinpointed  information about fault location
  • Accessible data – DayCor® presents human readable pictures of faults and of corona 
  • Efficiency – inspection with DayCor® reduces the time spent over finding defects
  • Cost effective – DayCor® cameras are NDT equipment and allow testing under rated voltages and normal temperature
  • Durability – Detecting faults in their early stages allows extending the life span of electrical grid components and defer ageing avoidable processes

Where can corona appear?

Bolts on conductor shoes

Raised strands on conductors

sharp edges on hardware

sharp edges on buswork

Bolts on bushings

Corona rings

Solutions for utilities


A robust comprehensive solution for multi sensors inspections by helicopters. Ideal for long transmission lines & hard to get or inaccessible locations.


A plug-N-play smart solution for inspections by UAS. Ideal cost-effective system for ad hoc & routine inspections.


Ergonomically designed to be hand carried, easily pulled out and used, with bright LCD to allow daytime operation, and typically simple to operate. Ideal for accessible locations


Systems designed to be mounted on vehicle roof and operated remotely. Ideal for long overhead lines with accessible paths.

Products Catalog

Ofil offers a variety of solutions to match budgets, needs, applications, locations or any other consideration. Knowing the main aspects of each model of corona camera will  facilitate the selection process. 

Need help? Call our award-winning support team 1.888.950.5557

Ofil develops and‭  ‬manufactures UV Bi-spectral optical and digital inspection systems with embedded proprietary patented Solar Blind technology‭. ‬Ofil aims at providing precise solutions for science‭, ‬industry and environmental wellness‭. ‬Ofil owns the brand‭ ‬name DayCor®‭ ‬that stands for Daytime Corona detection‭.  ‬


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