01 - OMICRON PD Seminar - Introduction of Partial Discharge Measurement
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Transcript of 01 - OMICRON PD Seminar - Introduction of Partial Discharge Measurement
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OMICRONPDSeminar2013
OMICRON 1.1
Introduction, History and Theory of Partial Discharge Measurement
Rene Hummel, Stephan Krber
Electric fields
What is partial discharge ?
> Partial discharge (PD) is a localized dielectric breakdown of a small portion of a solid or liquid electrical insulation system under high voltage stress.
> Definition from IEC 60270 Specification: Localized electrical discharge that only partially bridges the insulation between conductors and which can or cannot occur adjacent to a conductor.
Evidence of partial discharges
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OMICRONPDSeminar2013
OMICRON 1.2
Evidence of partial discharges
photo: VATech Hydro Austria
Evidence of partial discharges
photo: IPH Berlin
Evidence of partial discharges
photo: IPH Berlin
Evidence of partial discharges
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OMICRONPDSeminar2013
OMICRON 1.3
Evidence of partial discharges
tracking structures
Evidence of partial discharges
Video ...
video: IPH Berlin
Partial discharge / total discharge
photo: TU Berlin
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OMICRONPDSeminar2013
OMICRON 1.4
Electricity around us Important units
Charge Q [1Coulomb] = [1As]:
Charge in movement = CURRENT!!!
The more electrons per TIME interval, the higher is the current
Current = Charge per Time[A] = [Coulomb] per [s][A] = [Coulomb] / [s]
Charge = Current times TimeCharge = Current x Time
+
nucleus1st orbit
2nd orbit
electron-
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q =
Charge How to measure?
> Time Domain Integration q =
q
SI prefixes
kilo Volts [kV]
milli Ampere [mA]micro Farad [F]nano Coulomb [nC]pico Coulomb [pC]
Most used prefixes:
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OMICRONPDSeminar2013
OMICRON 1.5
Charge How it is measured
> Frequency Domain Integration
> More details in chapter FILTER
PD
C RpC
Analog PD measurement systems
PD
C RpC
Digital PD measurement systems
Filter is analogue!
PD
V
0- Detect
AD
MPD600 digital PD measurement system with digital filtering
PD
V
AD
AD
Digital Filter + PD Processor
Communications Processor
Power Management
Fiber Optic Cable
USB 2.0
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OMICRONPDSeminar2013
OMICRON 1.6
PD measurement with the OMICRON MPD software
test voltage over time
PD activity over time
voltage reading
disturbed voltage signal
What are partial discharges?
Partial discharge:
> Local electrical stress in the insulation or on the surface of the insulation
> Always generates electromagnetic signals
> Often accompanied by an emission of sound, light, heat and chemical reactions
Types of PD
> Internal PD> Void discharges, electrical treeing
> External PD> Corona> Surface discharges
Solid insulation
Outer semicon
Solid insulation
Inner semicon
Image Source: Andreas Kchler Hochspannungstechnik
External PD
Surface discharge Corona discharge
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OMICRONPDSeminar2013
OMICRON 1.7
Internal PD
Internal discharge in laminated material
Treeing
Cavity / void discharge
PD classification
Semicon layer protrusion(stress concentration at the tip)
Void (field strength doubling)
Lines ofelectrical field
En = 2