Best Practices in Transformer Maintenance NWPPA, Anchorage, AK October 2009 Wayne Bishop Business Development Manager
Today’s Presentation • • • •
Introduction to OMICRON Meeting the Challenges in our Industry Condition Assessment of Transformers New Technologies for Testing (Peter F Fong) ) – Current Transformer Testing – Dielectric Response Analysis
© OMICRON
January 13, 2008
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OMICRON • World Leader in the design and manufacture f t off test t t instruments i t t for f power system apparatus • Test Instruments in 130 countries • Team of 400 employees p y worldwide
© OMICRON
January 13, 2008
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OMICRON worldwide – A truly international team with a worldwide network
Houston / USA
Korea
Boston/ USA
Shanghai / China Hong Kong
Stafford / Great Britain New Delhi / India Bahrain
Cergy / France
Madrid / Spain
Berlin / Germany Melbourne / Australia Klaus / Austria
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Erlangen / Germany
11/9/2009
BUprim - Hardware – The Innovations in Primary Testing! MPD600 (PD)
DIRANA (DFR)
CPC 100 Multifunctional Primary Test Set CP GB1 Grounding Box
CP CU1 Coupling Unit
CPC 100 + CP TD1 Power Factor Testing CT Analyzer
FRAnalyzer (SFRA)
11/9/2009
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BUsec - Hardware
CMC 356
CMC 256plus
CMS 156
CMC 156
CMS 252
CMB IO-7
CMA 156
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11/9/2009
Challenges Facing our Industry With deregulation of the energy markets, the life span p of electrical assets becomes critical. • All assets including all transformers have to be in service as long as possible. • For transformers this can mean continuous operation over the life span of the asset at full load or even more since redundant transformer assets are not available.
© OMICRON
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Situation S tuat o for o Most ost of o Industry dust y
A large percentage of transformers are in service for more than 25 years – with the health of the transformers nott often ft known. k About 35% - 40% of all transformer faults are caused byy breakdowns in the aged insulation. • Temperature • Moisture
© OMICRON
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Situation Today Many of the transformers in Germany have an age of 25-30 years 100
No. off transforme ers
90 80 70 60 50 40 30 20 10 0
1-5
6-10
11-15 16-20
21-25
26-30
31-35
36-40
41-45
46-50 51-55
Age of transformers / years Betriebsalter der Transformatoren in Jahren
Problem: faults happen more often with increasing age © OMICRON
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Healthy 90 year old
© OMICRON
January 13, 2008
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Healthy? • • • • • • •
Blood Tests Urinal sis Urinalysis Temperature and Blood Pressure Ultrasound MRI Family Health History Life Style, Style Environment Environment, Stress
© OMICRON
January 13, 2008
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I this Is thi a Healthy H lth Transformer? T f ?
© OMICRON
January 13, 2008
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Si il Methodology Similar M th d l Healthy Person ? • Blood Tests, Urinalysis, p Temperature • Family History • Stress, Environment, Workplace, Lifestyle • Type of Care
© OMICRON
Healthy Transformer ? • DGA, Power Factor, % Moisture Insulation • Transformer Design History L dP Profile, fil L Location ti off • Load Transformer • Maintenance Program (TBM, CBM, RCM) January 13, 2008
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Transformer Diagnostics Review Patients History • Familyy History y of – High Blood Pressure and Heart Disease – High Cholesterol, Cancer Risks, etc.
Review History of Transformer • • • • • •
Maintenance History Operational History Service Advisories Factory Tests Site Inspections Routine Tests
© OMICRON
January 13, 2008
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Generator Transformer 27/400kV
HV Bushing Measuring Tap
LV Bushing
Diverter Switch
Tapped Winding High Voltage Winding
Tap Selector C Core © OMICRON
L Low V Voltage l Wi Winding di Page 15
Failure Mode Properties
•
Di l t i Stress Dielectric St
•
Thermal Degradation
•
Mechanical Stress
© OMICRON
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Maintenance Philosophies •
Time Based Maintenance (TBM) ¾ Perform P f Routine R ti P Preventative t ti Maintenance M i t
•
Reliability Centered Maintenance (RCM) ¾ Focus Resources on Bad Actors
•
Condition Based Maintenance (CBM) ¾ Require Indication while In-service
•
The Maintenance Spectrum ¾ Run to Failure
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November 9, 2009
Diagnostic Overkill
Transformer Tests • • • • • • • • •
DGA/Oil Screen/Furans Power Factor and Capacitance Excitation Current Turns Ratio (TTR) SFRA Leakage Reactance DC Winding Resistance Dielectric Frequency Response IR © OMICRON
January 13, 2008
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Dielectric
Thermal
Mechanical
DGA
DGA
SFRA
Oil Screen
Oil Screen
Leakage Reactance
PF/Cap
Thermal Imaging
Capacitance
Excitation Current
DC Winding Resistance
Excitation Current
TTR
DC Winding Resistance
Partial Discharge Dielectric Frequency Response © OMICRON
January 13, 2008
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Electrical Measurement Methods I Measurement Method Winding resistance (static) Winding Wi di resistance i t (dynamic)
Application Contact problems, broken or loose connections, broken conductors Contact problems at the diverter switch, broken transition resistors
Leakage reactance (stray Winding deformation reactance) Frequency Response of Broken parallel strands the Stray Losses (FRSL)
Indicated by High internal temperatures, e.g. indicated by DGA results or Buchholz Relay
FRT
off
DGA, Buchholz Relay
FRT
off
High through-fault currents
FRT
off
FT
off
FT
off
FT
off
High internal temperatures, e.g. indicated by DGA results High internal temperatures, No-load impedance Core problems, shorted turns e g indicated by DGA results e.g. High internal temperatures, Magnetising current Core problems, shorted turns e.g. indicated by DGA results F=Fingerprint, R=Routine, T=Troubleshooting, S=Special
© OMICRON
Kind of on-/offTest* line
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Electrical Measurement Methods II Measurement Method Turns ratio Frequency Response Analysis (FRA)
Application After Buchholz Relay Winding deformation, winding displacement, core faults, faulty screen or core
Insulation resistance
Insulation problems
Capacitance p and Dielectric Dissipation Factor Dielectric Response M Measurement t (FDS and PDC) Partial Discharge
Main insulation: ageing, g g, moisture - Bushings: ageing, partial Main insulation: ageing, moisture i t -B Bushings: hi ageing, partial Insulation problems
Indicated by Buchholz Relay has High through-fault currents, transportation
Kind on-/offof line Test* T off F(R)T
off
Breakdowns, Buchholz Relay
FRT
off
DGA
FRT
on/off
FRT
off ff
T
on/off
high water content in oilil / hi high h di dielectric l ti losses DGA
F=Fingerprint, g p R=Routine, T=Troubleshooting, g S=Special p
© OMICRON
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