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Corona

PPC Insulators
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Corona: Deadly Enemy for Polymeric Insulation

It has long been known that corona can lead to insulation failure. However not all aspects of the problem are fully understood and are still being researched, including magnitude and duration of corona to initiate degradation, best detection methods and... Read More

Failures on 400 kV Lines in Venezuela Highlighted Importance of Corona Rings on Composite Insulators

It is already well known that composite insulators used at transmission voltages have to be equipped with corona rings to reduce the risk of severe erosion to their polymeric housings. Yet, there are still cases where such insulators are either installed... Read More

Service Experience with Composite Line Insulators: EPRI Perspective

Service Experience Helped Identify Corona Issues Affecting Composite Line Insulators

Over the past 10-15 years, utilities began to experience increasing failures of polymeric insulator on 115 and 138 kV transmission lines. Subsequent investigation showed that these failures could often be attributed to high electric field (E-field) occurring... Read More

Verifying Corona, Pollution & Icing Performance of Insulation Structures

Use of composite insulators has increased rapidly. Historically, the main driver was excellent performance in polluted areas. But a more recent application has been in clean environments, where composite insulators provide possibilities to design more... Read More

Protecting Composite Insulators from Corona

One of the important design differences between silicone composite insulators and porcelain cap & pin or long rod types is their smaller shank diameter, made possible by the high strength glass-fibre reinforced core rod. This contributes to superior... Read More

Corona Shielding for HVDC Line Insulators

Power utilities and insulator manufacturers continue to express differing views as to the relative value of shielding electrodes in DC. Back in 1972, significant laboratory research had already been undertaken on the influence of shielding and grading... Read More

Comparing UV & IR Diagnostic Inspection of Lines & Substations

One of the issues in maintenance of overhead lines and substations relates to better understanding what is being revealed during ultraviolet or infrared inspections of equipment and hardware. Do these two technologies highlight the same problem or are they... Read More