Corona Testing requires specialized equipment and cannot be characterized with standard dielectric or induced voltage testers.
Partial discharge (Corona) can be minimized by choosing a supplier skilled in Corona abatement and with very extensive design experience, repeatable manufacturing processes, and the proper test equipment and procedures to measure Corona inception and extinction levels.
BIL ratings have been traditionally the domain of utility equipment manufacturers and gas or liquid filled transformer manufacturers. BIL may also be referred to as Basic Lightning Impulse Level, an indicator of its origin.
Power grids, especially in metropolitan areas are reaching a level of saturation that result in a greater susceptibility to load variances, including lightning strikes. Consequently, AC switches and high voltage industrial equipment are exposed to voltage surges normally absorbed by the grid.
Corona Testing can help identify latent failures before they occur. In addition, industrial equipment manufacturers are increasing the size and systems input voltage of their products. Consequently, power control systems and their related circuits must be able to exceed traditional voltage limits. Corona Testing applied to these is an indicator of durability in this environment.