So how is an arc detected?
High-impedance arcs and corona generate high-frequency current pulses that ride on the lower-frequency wave of the applied test-current waveform.
These pulses may have a frequency ranging from less than 30 kHz to more than 1 MHz and be very short in duration. Many times these pulses last much less than 10 μs (Figure 1).
Associated Research’s (AR) arc detection circuitry consists of a high pass filter circuit that responds only to frequencies greater than 10 kHz. These high-frequency signals are fed into a comparator and checked against an operator-programmed sensitivity level selected during the test setup.
The arc detection failure displayed by an AR hipot is separate from the high-limit failure displayed when dielectric breakdown has occurred.
An arc causes momentary high-frequency current spikes that ride on the low-frequency current waveform. Although these current spikes may not be the result of a catastrophic breakdown of the DUT’s insulation, they could indicate a problem with the insulation system that might become a safety issue at a later date.
|Title:||Why Is Arc Detection Important? – by Adam Braverman, Associated Research|
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