High voltage spikes onto wires/cables can progressively degrade the insulation performance and lead to an insulation breach and/or create conductive paths through the insulation. Wires/cables with consistent insulation systems and without air gaps or voids in the insulation will typically have a higher corona inception voltage and a higher extinction voltage. The higher the voltage for both of these, the better able they will be to withstand overvoltage conditions when in-service. This is of particular importance for those systems that will be used in higher voltage applications.
In this test, also referred to as the Partial Discharge test, the sample is exposed to a high voltage to determine the corona inception and corona extinction voltage (CEV).
Parameters that can be altered for this test include but are not limited to:
More information about the impact of corona on aircraft electric systems is available here.