Partial Discharge (PD) Testing - site example - MV Cable - Calibration скачать в хорошем качестве

Partial Discharge (PD) Testing - site example - MV Cable - Calibration

In this video we review again the measurement setup for PD testing and then we focus on the calibration procedure. Calibration is needed only if we intend to express the results of the measurement in pC (pico Coulombs) which is not the best practice when doing a site test - mostly because by respecting norm IEC 60270 (expressing results in pC) we adhere to the narrow frequency bandwidth of 110 kHz - 440 kHz which is somewhat limiting. It is limiting because it does PD measurement in narrow bandwidth we cannot save the waveform of the PD, which can be very useful when understanding the type of PD. Instead of pC we prefer to express the results in mV (milli Volts) - reason for that is - every acquisition unit Always measures only mV - and if we want to measure in IEC 60270 - we need to correlate the measured mV with injected pC - and that is what we show in this video. Another reason we are in 110 kHz to 440 kHz is because in that range mV (that acquisition unit measures) and pC are in direct correlation that is constant - and outside of that bandwidth - the correlation is not constant anymore. In the end video also shows a bit of TF map and also how calibration impulse reflects of the end of the cable..