IDAX 300 Insulation Diagnostic Analyzer Application of Dielectric Frequency Response Also known as:

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IDAX 300Insulation Diagnostic AnalyzerApplicatio
n ofDielectric Frequency ResponseAlso known
asFrequency Domain Spectroscopy
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Frequency Domain Spectroscopy
Measure at several frequencies Use Ohms law
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What is Spectroscopy?

• Method to isolate/identify building blocks in a
  composite material
• Example Identify material composition in samples
  from Mars
• Example Breaking down light into its different
  colors using a prism

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Frequency Domain Spectroscopy

• Changes in insulating materials (ageing) affect
  the capacitance and loss factor (PF, tan?)
• Frequency sweep, compared to traditional
  one-frequency Power Factor/Doble test, provides
  a lot more information on
• Insulation characteristics
• Ageing effects
• Influence of temperature
• Etc

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Traditional Power Factor Testing
Power factor
Frequency
60 Hz
1 mHz
1kHz
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Dielectric Frequency Response
Power factor
Frequency
60 Hz
1 mHz
1kHz
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Dielectric Frequency Response - Power Factor
Changes with Frequency
0.32 at 0.02 Hz
Power factor
0.0031 at 60 Hz
Frequency
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Oil Model

• Oil is modeled by its permittivity and
  conductivity (or tan?/power factor at 50/60 Hz)

Relative permittivity 2.2
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Paper/Pressboard Model

• Cellulose paper responses are modeled from a
  database of experimental data

Relative permittivity
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What affects the response
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Dielectric Frequency Response- Single PF value
is not enough to make the right decision-
Dielectric Frequency Response tells the story!
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DFR Application Areas

• Power transformers
• Instrument transformers
• Bushings
• Motors and generators
• Cables
• Generic testing of insulation systems

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Moisture MeasurementsIn Power Transformers
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Why measure moisture?

• A transformer with low moisture content is like a
  person in good condition
• A transformer can be loaded with confidence
  without risk for catastrophic failure.
• A person can work hard without risk for heart
  attack
• A wet transformer is like an overweight person
  with clogged arteries.
• The transformer owner has to limit load to avoid
  bubbling (explosion risk).
• Moisture in insulation increases the rate of aging

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Moisture in Power Transformers

• Power transformer insulation consists of oil
  impregnated cellulose and free oil. Almost all
  moisture is in the cellulose
• 25 tons of oil with water content of 20 ppm 0,5
  kg
• 2.5 tons of cellulose with 3 water content 75
  kg

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Water In Oil Analysis

• Power transformer insulation consists of oil
  impregnated cellulose and free oil. Almost all
  water is in the cellulose
• 25 tons of oil with water content of 20 ppm 0,5
  kg
• 2.5 tons of cellulose with 3 water content 75
  kg

20ppm (parts per million) in 25 tons of oil
3 water in 2.5 tons of cellulose
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Moisture in Power Transformers

• Power transformer insulation consists of oil
  impregnated cellulose and free oil. Almost all
  moisture is in the cellulose
• 25 tons of oil with water content of 20 ppm 0,5
  kg
• 2.5 tons of cellulose with 3 water content 75
  kg
• Moisture content in oil (it is almost constant in
  the cellulose) varies with temperature and oil
  aging status
• Aged oil resolves higher amounts of water than
  new oil
• Small moisture concentration makes sampling
  difficult

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Water In Oil Analysis
Oil samples taken at low temperatures have low
accuracy because the water has migrated to the
paper
Oil sample taken at 200C 4.0 water 6 ppm 1.0
water 3 ppm
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Moisture in Power Transformers

• Power transformer insulation consists of oil
  impregnated cellulose and free oil. Almost all
  moisture is in the cellulose
• 25 tons of oil with water content of 20 ppm 0,5
  kg
• 2.5 tons of cellulose with 3 water content 75
  kg
• Moisture content in oil (it is almost constant in
  the cellulose) varies with temperature and oil
  aging status
• Aged oil resolves higher amounts of water than
  new oil
• Small moisture concentration makes sampling
  difficult
• Moisture changes the dielectric properties of the
  cellulose paper/pressboard

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Moisture in Power Transformers

• Power transformer insulation consists of oil
  impregnated cellulose and free oil. Almost all
  moisture is in the cellulose
• 25 tons of oil with water content of 20 ppm 0,5
  kg
• 2.5 tons of cellulose with 3 water content 75
  kg
• Moisture content in oil (it is almost constant in
  the cellulose) varies with temperature and oil
  aging status
• Aged oil resolves higher amounts of water than
  new oil
• Small moisture concentration makes sampling
  difficult
• Moisture changes the dielectric properties of the
  cellulose paper/pressboard
• Moisture accelerates ageing

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Moisture in Power Transformers

• Moisture accelerates ageing

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Moisture in Power Transformers

• Power transformer insulation consists of oil
  impregnated cellulose and free oil. Almost all
  moisture is in the cellulose
• 25 tons of oil with water content of 20 ppm 0,5
  kg
• 2.5 tons of cellulose with 3 water content 75
  kg
• Moisture content in oil (it is almost constant in
  the cellulose) varies with temperature and oil
  aging status
• Aged oil resolves higher amounts of water than
  new oil
• Small moisture concentration makes sampling
  difficult
• Moisture changes the dielectric properties of the
  cellulose paper/pressboard
• Moisture accelerates ageing
• Moisture limits utilization

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Moisture in Power Transformers

• Moisture determines the maximum loading/hot-spot
  temperature for bubble inception (see e.g. IEEE
  Std C57.91-1995)
• Knowing moisture content allows for correct
  decision
• Leave as-is
• Dry-out
• Replace
• Scrap or Relocate?

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Moisture accelerates the aging process
Rated hot spot temperature IEEE Kraft paper 95C
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X-Y model of power transformer insulation
Cellulose Blue color Oil Red color
Typical valuesX barriers in the main duct
(15-55) Y spacers of the circumference
(15-25)
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Moisture estimation process

• Measure tan delta/power factor from 1 kHz to 2
  mHz
• Send results to MODS
• Enter insulation temperature (top-oil
  temperature)
• MODS matches measured curve to model curve
  (automatically) by varying parameters that
  affects the shape of curve to find best match
• Relation of solid (cellulose) vs. liquid (oil)
  insulation between winding
• Moisture in solid insulation
• Oil conductivity

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Oil Response 1000Hz-1mHz
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Solid Paper 1000Hz-1mHz
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Transformer Insulation 1000Hz-1mHz
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Interpretation of moisture content

• lt 0.5 New transformer
• 0.5 - 1.5 Dry insulation
• 1.5 - 2.5 Medium wet insulation
• 2.5 - 4 Wet insulation
• gt 4 Very wet insulation

Interpretation of moisture content of solid
insulation ( of weight water per weight
cellulose)
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Moisture estimation process
Measured curve
Right click
Select Send toMODS
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Moisture estimation process
Amount of oil
Spacers
Barriers
Model curve
Measured curve
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Moisture estimation process
3. Click Auto match
1. Check all checkboxes
2. Enter temperature
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Moisture estimation process
Result!
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Other applications
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DFR on Bushings
C1 measurement on H3 is wet
Capacitance increases at lower frequencies And
Losses are higher
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DFR for Motors and Generators

• Measure power factor and capacitance vs frequency
  to detect ageing deterioration

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Verification of DFR/IDAX performance

• Accredited test system at ABB transformers
• Project REDIATOOL comparing DFR with other
  methods for measuring moisture in transformers.
  Results published at CIGRE 2006 (paper
  D1-207).http//www.uni-stuttgart.de/ieh/forschung
  /veroeffentlichungen/CIGRE_paperD1-207_Gubanski.pd
  f
• Examples of other independent verification bodies
• IREQ (Canada)
• EPRI (China)
• IEPS/Schering-Institute (Germany)
• CESI (Italy)
• KTH (Sweden)
• Tennesse Tech (USA)

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ABB Transformer Diagnostics
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IDAX-300 Insulation Diagnostic Analyzer
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IDAX System

• HW
• Test signal 0 200 V peak 0 50 mA peak
• Frequency 0.0001 Hz 10000 Hz (IDAX-300)
• Sample range 10 pF 100 µF
• 2-ch measurement (IDAX-300)
• SW
• IDAX SW for measurement control and analysis
• Moisture analysis SW (MODS)
• Automatic moisture assessment in oil impregnated
  cellulose

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Cables
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Software
Nameplate Info
Object and Test Browser
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Software
Test settings
Graphical Hook-Up Diagram
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Software
Graph View
Presentation selector Power Factor Chosen
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Software
Result at 60Hz
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Summary IDAX 300

• Instrument for moisture assessment in transformer
  insulation
• Built in modeling software for quick and reliable
  results
• Measures the moisture where it is, at any
  temperature
• Light weight, fast and accurate
• Can be used for other applications as well
• CTs
• Bushings
• Rotating machines
• Cables
• Reveals the reason for high PF value - Moisture
  or Contamination?
• Well documented and well proven method