Corona Extinction Voltage
Electrical FOR: Insulation $1,740High 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:
- Temperature
- Altitude
More information about the impact of corona on aircraft electric systems is available here.
Procedure
- Perform visual examination of the sample.
- Prepare sample(s) for the test.
- Connect sample to test system. If the sample is a shielded cable, then voltage placed between the conductor and shield. If the sample is an individual wire, place the sample in a water bath with return electrode.
- Slowly raise the test voltage on the sample until the corona inception is detected via oscilloscope.
- Slowly lower voltage on the sample until the corona extinction is detected.
- Record results.
Covered specifications
- AS4373 Method 502
- AS6370 Method 4.6.5
- ASI/ICEA T-24-380-2013
- ASTM D1868
- ASTM D3032 Method 25
- EN3475 Method 307
- MIL-DTL-17 Method 4.8.6
- ANSI/ICEA T-24-380-2019 Method N/A
- AS654 Method 5.3.6
- ASTM D2275
- ASTM D3032 Method 24
- EIA-364 Method 44A
- EN2591 Method 227
- MIL-DTL-17 Method 4.8.06
- MIL-PRF-39012 Method 4.6.19