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IEC 62478A Prospective Standard forAcoustic
and ElectromagneticPartial Discharge
MeasurementsMichael Muhr Univ.-Prof.
Dipl.-Ing. Dr.techn. Dr.h.c.Institute of High
Voltage Engineering and System Management
University of Technology Graz
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Partial Discharge (PD) Measurement

• Sensitive nondestructive method
• as important diagnostic tool
• for evaluation of the insulation condition
• PD-defect
• Location and Detection

Electrical
Non electrical methods
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Partial Discharge Measurement
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PD-Detection Methods IEC 60270

• Conventional electrical measurement
• Integration at frequency domain
• Narrow-band
• Wide-band
• Integration at time domain

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PD-Detection Methods

• Electrical measurements with high frequencies
• HF / VHF method 3 MHz to 300 MHz
• UHF method 300 MHz to 3 GHz
• Acoustic measurements 10 kHz to 300 kHz
• Optical measurements ultraviolet visible
  infrared range
• Chemical measurements

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Optical PD-Measurement
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PD Optical Detection
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Optical PD-Detection in GIS
Emission spectrum of corona discharges in SF6
Test arrangement for optical PD-measurement
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Chemical PD-Measurement

• Sensors and analyser
• H2 Sensor
• DGA (Gas in oil analysis)
• Ozone analysis
• Gas Analysis

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Chemical PD-Measurement
PD partial discharges T1 temperatures T lt 300 C
D1 discharges with low energy T2 temperatures 300 C lt T lt 700 C
D2 discharges with high energy T3 temperatures T gt 700 C
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HF / VHF PD-Measurement

• HF / VHF Partial Discharge Detection
• Frequency range 3 MHz to 300 MHz
• HF 3 30 MHz
• VHF 30 300 MHz
• Measuring systems
• Narrow-band, band width lt 2 MHz
• Wide-band, band width gt 50 MHz
• Sensors
• Capacitive, inductive, electromagnetic

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HF / VHF PD-Measurement

• Rogowski coil

Measuring for HF PD-detection on machines, VHF
PD-coupler, Split ring Rogowski coil
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HF / VHF PD-Measurement
impulsesource / - No. signal at coupling output signal at coupling output signal at coupling output signal at coupling output
impulsesource / - No. A B C D
joint /1 X X
left cable / 2 X X
right cable / 3 X X
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HF / VHF PD-Signal Damping

• Damping effects
• Geometric proportions
• Discontinuities
• Impulse form
• Refraction
• Reflection
• Frequency
• Material

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UHF PD-Measurement

• UHF Partial Discharge Detection
• Transient electromagnetic waves
• Frequency range 300 MHz to 3 GHz
• Narrow band ( 5 MHz)
• Wide band ( 2 GHz)
• Propagation - TM Wave (Transversal magnetic
  wave)
• - TE Wave (Transversal electric wave)
• - TEM Wave
• Not coupled to the conductor

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UHF PD-Measurement
UHF PD-measurement
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UHF PD-Sensors
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Sensitivity Verification
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UHF PD-Fault Location
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UHF PD-Signal Damping, Sensitivity

• Damping effects
• Frequency
• Geometries
• Conductor material
• Mode type
• Reflection and refraction
• Sensivity
• Facility configuration
• Failure location
• Location of the sensor
• Measurement equipment

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Acoustic PD-Measurement

• Acoustic Partial Discharge Detection
• Acoustic signal as a result of the pressure wave
  produced by PD
• Frequency spectrum 10 Hz up to 300 kHz

SF6
Box
AE Sensor
Air
Principle schematic to the acoustic PD-detection
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Acoustic PD-Sensors
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Acoustic PD-Measurement
PD-Detector
AE Sensor
amplifier
Filter
A/D Converter
Acoustic PD-detection system
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Acoustic PD-Measurement

• Damping effects
• Equipment dispersion
• Construction
• Insulation structures
• Gas pressure
• Encapsulation material
• Absorption during a medium to another
• Geometrical spreading of the wave

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Opto-Acoustic PD-Measurement
Experimental setup of the optical interferometric
detection of PD
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IEC TC42 WG 14

• Content 1
• Scope
• Phenomena
• PD occurrence in discharging defects
• Frequency / time behaviour
• Specifies of HV-components
• Applicability for detection
• Normative References
• Definitions
• Sensors
• Types, parameters, positioning
• Location (time and frequency domain) vs
  measurement only

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IEC TC42 WG 14

• Content 2
• Transmission Aspects
• A) UHF Aspects
• PD source, quantity E V/mspectrum, filed mode,
  signal strength, magnitude, characteristic
  impedance, velocity of medium, distance, activity
• Sensor-antenna, basic quantity mtype,
  bandwidth, position, receiving area, transfer
  impedance, characteristics
• Reading quantity V
• Derived quantitymeasuring equipment, bandwidth,
  center frequency, tuning

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IEC TC42 WG 14

• Content 3
• B) HF / VHF Aspects
• PD source, quantity V or Aelectric or
  magnetic signal, impedance, signal magnitude,
  distance, activity
• Sensor impedance R, L, Ctype, bandwidth,
  position, dielectric attenuation, distortion,
  polarity aspects
• Reading quantity V, A
• Derived quantitymeasuring equipment, center
  frequency, tuning, bandwidth, pulse resolution

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IEC TC42 WG 14

• Content 4
• C) Acoustic Aspects
• Mechanical pressure, quantity Pascalpressure
  waves, modes, acoustic impedance, delay,
  propagation velocity, distance
• Sensor impedancepiezo electric, composite
  material, optical, microphone, directivity,
  position, coupling, bandwidth, linearity
• Reading quantity V
• Derived quantitymeasuring equipment, pulse
  counter, pulse pattern

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IEC TC42 WG 14

• Content 5
• System Checks
• Performance and sensitivity check
• UHF Aspectsperformance check functional check
  of the whole measuring path including sensor and
  PD acquisition systemsensitivity check emission
  of electromagnetic waves into test objects,
  distance
• HF / VHF Aspectsperformance check sensor to
  sensor coupling in a specific arrangementsensitiv
  ity check injection of field signal to test
  object, distance
• Acoustic Aspectsperformance and sensitivity
  check recommendation of acoustic standards

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IEC TC42 WG 14

• Content 6
• pC Correlation
• HF / VHF / UHF pulse generator injection to
  determine relation between pC and measured
  quantities
• Acoustic can not compared to pC without knowing
  the type of PD source
• New quantities
• parameters linear with sensor output mV
• parameters quadratic with sensor output mW
• effective height mm ratio between sensor
  output and incoming electrical field
• Effective aperture mm2 ratio between maximum
  sensor output power and power density of incoming
  electrical field
• sensor gain dBi ratio between receiving power
  antenna and receiving power of isotropic radiator

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IEC TC42 WG 14

• Content 7

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IEC TC42 WG 14

• Content 8
• Non Standardization
• Applicable sensor
• Test and measuring configurations
• Interpretation task of the component panels

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