This document discusses asset management and maintenance delivery, focusing on predictive maintenance through diagnostic testing of electrical assets. It provides an overview of asset management principles and decision making, then details various online and offline diagnostic tests for transformers, switchyards, motors, switchgear, and cables. These include tests like oil analysis, thermography, partial discharge testing, and insulation resistance measurements. Condition criteria are outlined to assess asset health and determine maintenance needs based on test results. Consistency in test setup and documentation is emphasized for effective trend analysis.

1. Asset Management
Maintenance Delivery - Diagnostic Testing Electrical Assets

2. Agenda
• What is Asset Management
• Asset Management Decision Making
• Maintenance Delivery
• PdM – Diagnostic Testing

3. ISO 55000:2014 Asset Management Definition
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“The coordinated activity of an organization to realise value from assets”

4. Asset Management System Elements

5. IAM Conceptual Model

6. 39 Subjects of Asset Management by IAM

7. Asset Management Decision Making
• Capital Investment Decision Making
• Operation & Maintenance Decision Making
• Life Cycle Value Realisation
• Resourcing Strategy & Optimisation
• Resourcing Strategy
• Shutdowns & Outage Strategy

8. Condition Assessment Criteria
`what is the condition of the asset`
OR
`When will the condition of the asset become unacceptable`

9. Operation & Maintenance Decision Making
• Maintenance regimes must provide value to the organisation to be justified
Tools to define optimum maintenance frequencies
• FMEA – Failure Mode and effects Analysis
• RCM – Reliability Centred Maintenance
• RBI – Risk Based Inspection – optimise
Where companies have adopted manufacturers maintenance regimes they must look to justify maintenance
schedules. Are labour and resources used efficiently?

10. Maintenance Delivery
Preventive PM – Often manufacturer recommended PM frequencies, functional system checks (SIL), Haz Area
Predictive PdM – Equipment diagnostic testing techniques
Condition Monitoring CM – Machines(PROGNOST®/Bentley Nevada) – Online PD
Corrective - Repair or adjustment for a condition detected in PM/PdM
Emergency – Breakdowns equipment failures

11. PdM - Primary Electrical Assets
• Transformers
• Motors
• Switchgear/Switchyards
• HV Cables

12. PdM - Transformer Diagnostic Testing
Online
• Oil Analysis – DGA – Furans
• Infrared Thermography
• Acoustic Emissions (AE)
• UHF Partial Discharge
• Radio Frequency Interference (RFI)
Note: - The test methods listed are not the only test that
can be performed, this list is made up of common tests
requested by customers.
Offline
• Insulation Resistance
• Power Factor/DDF
• DC Winding Resistance
• Turns Ratio
• Leakage Impedance
• SFRA
• Dirana

13. Review – Offline Transformer Diagnostic Testing
Polarisation Index
IEEE Std 62-1995 Paragraph 6.1.5
IEC 60076-1 (2000), clause 10.1.3
Turns Ratio
IEEE Std 62-1995 Paragraph 6.1.2
IEC 60076-1 (2000), clause 6
turns ratio tolerance should be within 0.5% of the
rating plate specifications for all windings
Winding Resistance
IEEE Std 62-1995 Paragraph 6.1.1
IEC 60076-1 (2000), clause 10.2
winding resistance within 5% tolerance compared to
the rating plate and previous results
Insulation Power Factor/ Tan Delta
IEEE- std 62-1995
IEEE std 57.12.90-1999 clause 10.10 [51]
IEC 60076-1 (2000) clause 10.1.3
Additional tests include but not limited to
• Dirana
• SFRA
PI Condition
<1 Dangerous
1 - 1.1 Poor
1.1 – 1.25 Questionable
1.25 - 2 Fair
>2 2.0 Good
Transformer
Condition of Insulation
Good Maybe
Acceptable
Should be
investigated
New DF < 0.5% - -
Serviced-aged DF < 0.5% 0.5% < DF < 1% Df > 1%
All values measured at 20°C

14. Review – Online Transformer Diagnostic Testing
Condition
DGA Good Acceptable Questionable Unacceptable
Hydrogen (H2) < 100 ppm 101 to 700 ppm 701 to 1,800 ppm > 1,800 ppm
Methane (CH4) >120 ppm 121 to 400 ppm 401 to 1,000 ppm > 1,000 ppm
Ethane (C2H6) < 65 ppm 66 to 100 ppm 101 to 150 ppm > 150 ppm
Ethylene (C2H4) < 50 ppm 51 to 100 ppm 101 to 200 ppm > 200 ppm
Acetylene (C2H2) < 35 ppm 36 to 50 ppm 51 to 80 ppm > 80 ppm
Carbon Monoxide (CO) < 350 ppm 351 to 570 ppm 571 to 1,400 ppm > 1,400 ppm
Carbon Dioxide (C02) < 2,500 ppm 2,500 to 4,000 ppm 401 to 10,000 ppm > 10,000 ppm
Oxygen (O2) <0. 2 % 0.2 – 3.5 % > 3.5 % NFG
Nitrogen (N2) < 1 % 1 - 10 % > 10 % NFG
TDCG < 720 ppm 721 – 1,920 ppm 1,921 – 4,630 ppm > 4,630 ppm
Insulation Fluid Analysis (IFA)
Moisture – 220/132 kV < 5 ppm 5 to 15 ppm 15 to 25 ppm > 25 ppm
Moisture – 33 kV + MV < 10 ppm 10 to 25 ppm 25 to 30ppm > 30 ppm
Moisture % - M/DW < 0.5 M/dw 0.5 to 1.5 % M/dw 3.3-6% M/dw > 7% M/dw
Dielectric Breakdown (BV) – 220/132 kV > 50 kV 40 to 50 kV 30 to 40 kV < 30 kV
Dielectric Breakdown (BV) – 33 kV > 40 kV 30 to 40 kV 20 to 30 kV < 30 kV
Dielectric Dissipation/ Factor (PF) < 0.5 % 0.5 % to 1.0% 0.5 % to 1.0% Inc > 1.0 %
IFT - Interfacial Tension > 32 dynes/cm 28 - 32 dynes /cm 22 < 28 dynes /cm < 22 dynes/cm
Acidity No. – ASTM D-974 < 0.03 mgKOH/g > 0.03 < 0.05 mgKOH/g > 0.05 < 0.20 mgKOH/g
> 0.20
mgKOH/g
Furans 0.01 ppm 0.1 ppm 1.00 ppm > 5 ppm
Condition DP
Furaldehyde
Content (ppm)
Good 717 - 1003 0.01
Moderate Deterioration 431 - 717 0.1
Extensive Deterioration 232 - 431 1
End of Life < 232 >5
DP - Degree of Polymerisation

15. Review – Online Transformer Diagnostic Testing

16. PdM - Switchyard Diagnostic Testing
Bushings - CTs – VTs – Circuit Breakers
• Insulation Resistance
• DDF
• Thermography
• PD
• Corona
• Oil Analysis

17. Review – Switchyard Diagnostic Testing
Corona Camera
RFI - Radio Frequency
Interference (RFI)

18. Review – Switchyard Diagnostic Testing
Bushing Test
Capacitance C2 Power & Dissipation Factor
Good <0.5% -
Monitor
>0.5% < 1.0% &
5% variation from
nameplate
Between nameplate power factor & up to
twice nameplate power factor
Poor
>0.5% < 1.0% &
10% variation from
nameplate
Between twice nameplate power factor & up
to 3 times nameplate power factor
Replace
> 1.0% and increasing
> 10% of nameplate
Above 3 times nameplate power factor

19. PdM – Motor Insulation Diagnostic Testing
Offline
• DC Insulation Resistance – PI
• DLA/DDF
• Partial Discharge (PD)
• ElCid
• RSO
• Note: - The test methods listed are not the only test
that can be performed, this list is made up of
common tests requested by customers.
Online
• Partial Discharge

20. Review – Motor Insulation Diagnostic Testing
DC Insulation Resistance
Insulation Power Factor DDF/ Tan Delta
DDF testing proves more beneficial when trending(monitoring change)
PI Condition
<1 Poor
1-2 Questionable
2-4 Fair
>4 Good
Insulation System %PF@2kV %PF Tip-Up
Asphalt-Mica 3.0 or less 2.0 or less
Polyester & Epoxy Mica 1.0 or less 1.0 or less
Pre-1980 Epoxy Mica 1.5 or less 1.5or less

21. Review – Motor Insulation Diagnostic Testing
Partial Discharge
Base lining and continues trending provides best value from PD testing.
ElCiD – Electromagnetic Core imperfection Detection

22. PdM – Switchgear Condition Monitoring
Online
• Partial Discharge
Offline
• Partial Discharge
• Insulation Resistance
• Circuit Breakers M`tce

23. Review – Switchgear Diagnostic Testing
Circuit Breaker
• Contact speed/motion measurement
• Close over travel measurement
• Close damping measurement
• Trip damping measurement
• Arcing contact timing
• Dynamic resistance measurement (DRM)
• Oil Sampling
• Motor-mechanism checks, function check safety devices etc.

24. PdM – Switchgear Diagnostic Testing
Partial Discharge Survey

25. PdM – HV Cable Diagnostic Testing
Offline
• Partial Discharge Mapping (OWTS)
• VLF
• Tan Delta
Online
• Partial Discharge

26. PdM – HV Cable Diagnostic Testing
DLA Testing (Tan Delta)

27. PdM – HV Cable Diagnostic Testing

28. Consistency in Diagnostic Testing Techniques
It is critical that test conditions are recorded when testing to enable trending
• Temperature
• Humidity
• Load
• Test equipment
• Type Model
• Test voltage/current
• Connection arrangements

29. Thank You