TY - JOUR

T1 - A novel wideband partial discharge measuring circuit under fast repetitive impulses of static converters

AU - Sargazi, R.

AU - Akbari Azirani, Asghar

AU - Werle, P.

AU - Borsi, H.

N1 - Funding Information: The authors would like to thank Alexander von Humboldt foundation of Germany for supporting the preparation of this contribution.

PY - 2021/6

Y1 - 2021/6

N2 - Nowadays fast switching power electronic devices are used for driving high voltage electric rotating machines. These power supplies apply sharp transient voltage at the time of switching. To study the effect of these stresses on the insulation system, investigating Partial Discharge (PD) during voltage rapid changes is of special interest. Although, the implemented coupling capacitor in a conventional PD measuring circuit provides a low impedance pass for the PDs, but imposes a transient current caused by sharp changes of voltage at the time of switching; hence, the measuring impedance of the conventional partial discharge equipment cannot distinguish an actual PD pulse from the mentioned transduced capacitive current pulses. Currently, two options are available in order to cope with this issue, including UHF technique and implementation of band pass filters. On the one hand, calibration of the PD pulses in the UHF method is not possible; hence, the PD test results of different manufacturers of machines under such stresses cannot be compared, which is the main drawback. On the other hand, one has to remove a wide range of frequency components of PD pulses that makes PD calibration procedure to be invalid. In this paper, a resonant full bridge topology is implemented to cancel out the capacitive pulse shaped current, where the PD pulses are captured directly via electrical method in a symmetric introduced configuration. The resulting inrush current has drastically reduced and a wideband measuring circuit with a true calibration process has become possible.

AB - Nowadays fast switching power electronic devices are used for driving high voltage electric rotating machines. These power supplies apply sharp transient voltage at the time of switching. To study the effect of these stresses on the insulation system, investigating Partial Discharge (PD) during voltage rapid changes is of special interest. Although, the implemented coupling capacitor in a conventional PD measuring circuit provides a low impedance pass for the PDs, but imposes a transient current caused by sharp changes of voltage at the time of switching; hence, the measuring impedance of the conventional partial discharge equipment cannot distinguish an actual PD pulse from the mentioned transduced capacitive current pulses. Currently, two options are available in order to cope with this issue, including UHF technique and implementation of band pass filters. On the one hand, calibration of the PD pulses in the UHF method is not possible; hence, the PD test results of different manufacturers of machines under such stresses cannot be compared, which is the main drawback. On the other hand, one has to remove a wide range of frequency components of PD pulses that makes PD calibration procedure to be invalid. In this paper, a resonant full bridge topology is implemented to cancel out the capacitive pulse shaped current, where the PD pulses are captured directly via electrical method in a symmetric introduced configuration. The resulting inrush current has drastically reduced and a wideband measuring circuit with a true calibration process has become possible.

KW - Enameled wires

KW - Partial discharge (PD)

KW - Roebel bars

KW - Rotating machines

KW - Static converters

KW - Stator winding

UR - http://www.scopus.com/inward/record.url?scp=85103946604&partnerID=8YFLogxK

U2 - 10.1016/j.measurement.2021.109353

DO - 10.1016/j.measurement.2021.109353

M3 - Article

AN - SCOPUS:85103946604

VL - 178

JO - Measurement: Journal of the International Measurement Confederation

JF - Measurement: Journal of the International Measurement Confederation

SN - 0263-2241

M1 - 109353

ER -