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IEC 62478 A Prospective Standard for Acoustic and Electromagnetic Partial Discharge Measurements Michael Muhr Univ.-Prof. Dipl.-Ing. Dr.techn. Dr.h.c.

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Presentation on theme: "IEC 62478 A Prospective Standard for Acoustic and Electromagnetic Partial Discharge Measurements Michael Muhr Univ.-Prof. Dipl.-Ing. Dr.techn. Dr.h.c."— Presentation transcript:

1 IEC A Prospective Standard for Acoustic and Electromagnetic Partial Discharge Measurements Michael Muhr Univ.-Prof. Dipl.-Ing. Dr.techn. Dr.h.c. Institute of High Voltage Engineering and System Management University of Technology Graz

2 IEC M. Muhr 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

3 IEC M. Muhr Partial Discharge Measurement Optical Mechanical Chemical Acoustic Opto-acoustic HV ElectricalIEC HF/VHF/UHF Optical Effects (Light) Pressure Wave (Sound) Discharge Effects Dielectric Losses High Frequency Waves Chemical Effects Heat Macroscopic-Physical Effects Detection Methods

4 IEC M. Muhr PD-Detection Methods IEC Conventional electrical measurement - Integration at frequency domain Narrow-band Wide-band - Integration at time domain G Z Filter HV-Source Test object Coupling capacitor PD-System HV measure PD Pulse Quadripole Measuring impedance

5 IEC M. Muhr 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 - Optical - Chemical Directional microphone PD HV Acoustic

6 IEC M. Muhr Fiber-optic cable Infrared camera EyeOptical sensor Coronascope Light produced during the discharge Low-light enhancer Optical detection and localisation Outside not accessible: - Fibre-optic cable - Collimator - Photodiodes Outside accessible: - Eye - Low-light amplifier - Coronascope Optical – PD-Measurement

7 IEC M. Muhr PD – Optical Detection Measuring circuit after IEC and optical measuring system Optical fibre with lens Optical fibre Lens Peak Medium oil Observation area Fluorescent optical fibre conventional opt. fibre Peak fluorescent opt. fibre Plate Rd PC LWL M ST CC VP PR W IEC 270 optical system Oscilloscope, ADU Signal- conversion Voltage supply

8 IEC M. Muhr Test arrangement for optical PD-measurement Optical – PD-Detection in GIS Emission spectrum of corona discharges in SF 6 SF 6 Photomultiplier Conv. PD Detector ADU I/U Oscilloscope

9 IEC M. Muhr SF 6 Higher temperatures ArcPartial discharge decomposition fluoric compounds (Fluoride) Sulfur-compounds (Sulfate, Sulfide) Sulfur- fluoric- compounds Chemical – PD-Measurement Sensors and analyser - H 2 Sensor - DGA (Gas in oil analysis) - Ozone analysis - Gas Analysis

10 IEC M. Muhr PD partial discharges T1 temperatures T < 300° C D1 discharges with low energy T2 temperatures 300° C < T < 700° C D2 discharges with high energy T3 temperatures T > 700° C IEC DGA Gas ratio values Chemical – PD-Measurement

11 IEC M. Muhr 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 < 2 MHz - Wide-band, band width > 50 MHz Sensors - Capacitive, inductive, electromagnetic

12 IEC M. Muhr Measuring for HF – PD-detection on machines, VHF – PD-coupler, Split ring Rogowski coil Rogowski coil PD Analyser HF / VHF – PD-Measurement Rogowski coil

13 IEC M. Muhr HF / VHF – PD-Measurement Principle of the coupler sensor direct. coupling A B direct. coupling C D impulse source / - No. signal at coupling output ABCD joint /1–XX– left cable / 2X–X– right cable / 3–X–X

14 IEC M. Muhr B A C-Sensor LDP-5 HF / VHF – PD-Signal Damping Damping effects: - Geometric proportions - Discontinuities - Impulse form - Refraction - Reflection - Frequency - Material

15 IEC M. Muhr 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

16 IEC M. Muhr UHF – PD-measurement low-pass filter Peak detector PD measuring instrument PRPD pattern Wide bandNarrow band Spectrum analyser amplifiers UHF – PD-Measurement

17 IEC M. Muhr UHF – PD-Sensors - Mobile UHF-window sensor - Conventional UHF-sensors Disc sensor Cone sensor Conductor Cage Dectector Field grading electrodes Conductor Cage Detector

18 IEC M. Muhr Sensitivity Verification UHF measurement C1C2 Signal 1 Defect UHF measurement PG C1C2 Signal 2 Impulses of variable amplitude

19 IEC M. Muhr UHF – PD-Fault Location L1 Schematic arrangement Sensor 1 Pre amplifier Measuring instrument L2 Sensor Sensor Sensor 2 Time delay Zeit Amplitude 1 2 Defect

20 IEC M. Muhr Sensitivity of developed UHF-sensors 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

21 IEC M. Muhr Principle schematic to the acoustic PD-detection 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 SF 6 Air Box AE Sensor

22 IEC M. Muhr Acoustic – PD-Sensors HV Time delay Sensor PD Time Signal Directional microphone PD HV - Piezo-electric (sound emission) - Condenser microphones - Structure-born sound-resonance - Accelerometer - Opto-acoustic-sensor

23 IEC M. Muhr Acoustic – PD-detection system amplifier Oscilloscope AE Sensor PD-Detector Filter A/D Converter Acoustic – PD-Measurement

24 IEC M. Muhr 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 Acoustic fingerprint of a overhead line conductor

25 IEC M. Muhr Experimental setup of the optical interferometric detection of PD Opto-Acoustic – PD-Measurement Laser Reference optical fibre coil Sensing optical fibre coil Oil tank High Voltage PD-source Detector Beam Splitter Beam Splitter

26 IEC M. Muhr 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

27 IEC M. Muhr IEC TC42 WG 14 Content 2 - Transmission Aspects A) UHF Aspects PD source, quantity E [V/m] spectrum, filed mode, signal strength, magnitude, characteristic impedance, velocity of medium, distance, activity Sensor-antenna, basic quantity [m] type, bandwidth, position, receiving area, transfer impedance, characteristics Reading quantity [V] Derived quantity measuring equipment, bandwidth, center frequency, tuning

28 IEC M. Muhr IEC TC42 WG 14 Content 3 B) HF / VHF Aspects PD source, quantity [V] or [A] electric or magnetic signal, impedance, signal magnitude, distance, activity Sensor – impedance [R, L, C] type, bandwidth, position, dielectric attenuation, distortion, polarity aspects Reading quantity [V, A] Derived quantity measuring equipment, center frequency, tuning, bandwidth, pulse resolution

29 IEC M. Muhr IEC TC42 WG 14 Content 4 C) Acoustic Aspects Mechanical pressure, quantity [Pascal] pressure waves, modes, acoustic impedance, delay, propagation velocity, distance Sensor – impedance piezo electric, composite material, optical, microphone, directivity, position, coupling, bandwidth, linearity Reading quantity [V] Derived quantity measuring equipment, pulse counter, pulse pattern

30 IEC M. Muhr IEC TC42 WG 14 Content 5 - System Checks Performance and sensitivity check UHF Aspects performance check: functional check of the whole measuring path including sensor and PD acquisition system sensitivity check: emission of electromagnetic waves into test objects, distance HF / VHF Aspects performance check: sensor to sensor coupling in a specific arrangement sensitivity check: injection of field signal to test object, distance Acoustic Aspects performance and sensitivity check: recommendation of acoustic standards

31 IEC M. Muhr 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 [mm 2 ] – 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

32 IEC M. Muhr IEC TC42 WG 14 Content 7 EM – PD Source Basic Quantity E [Volt / meter] Sensor – Antenna Basic Quantity e.g. [meter] Reading Quantity [Volt] PD [pC] Quantity [m Watt] Low Standard Deviation Definition of Transfer Characteristic Definition of Transfer Characteristic Low Standard Deviation System Check Physical Generic Aspect Mathematical Term Quantity [Volt] PD [pC] High Standard Deviation

33 IEC M. Muhr IEC TC42 WG 14 Content 8 Non Standardization - Applicable sensor - Test and measuring configurations - Interpretation – task of the component panels

34 IEC M. Muhr Thank You for Your Attention


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