US 1.888.950.5557 | CN 86.1580.215.4221


US 1.888.950.5557 | CN 86.1580.215.4221

Effect of End Fitting Design on Controlling Corona

Share on facebook
Share on twitter
Share on linkedin
Share on email
Share on print

EPRI Research Results after 20,000 Hours of Aging

Based on the study of hundreds of in-service polymer insulators and decades of insulator research, EPRI understands the importance of controlling the electric field (E-field) around the end fitting which in turn controls the presence of corona. The insulator end fitting shape and size are a factor in that control. Direct contact with corona discharges is one of the leading causes of brittle fracture failure and flashunders.

This report describes EPRI’s effort to develop a small scale short term test to assess how the design of the polymer insulator end fitting controls the position and direction of end fitting corona and its effect on the longevity of the insulators. Small scale tests such as described in this report can help utilities specify uniform performance criteria for polymer insulators in their specification documents.

This test was designed using easy to manufacture parts and off the shelf components making the test lower cost than the large counterparts.

The latest version of the test has the insulators energized in a 90+ relative humidity chamber which has resulted in accelerated degradation of the hydrophobicity. With the rubber becoming hydrophilic, the stress on the insulator shifted away from the end fitting towards the grounded cage.

In 2020, a new test with new insulators is planned with revised test parameters to improve the representativeness of aging of the end fitting seal region.

Available on EPRI’s Research >>







DayCor® cameras identify end fitting issues and pinpoint their location, as seen in these pictures that were taken by UVollé, Superb and Luminar HD cameras.

You might like these too...

Sustainability Considerations Conerning Electrical Gridlines

A recent environmental report by the US EPA revealed that the electric power industry contributed over 25% of the total greenhouse gas (GHG) emissions in 2020 alone. This is closely followed by the industry sector, with around 24% of the total GHG for the same year. From this data, you can see the crucial role that the electric power and industry sector plays in changing their practices to reduce the detrimental effects of GHG on the environment. Apart from industry leaders, sustainability experts, like environmental and conservation scientists, study the impacts of GHG and recommend preventive sustainability practices.

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.  Download Catalog…

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.  ‬


Helicopters & Fixed Wings

Camera Cores

Australia | New Zealand

Get Local Distributor Name