CIGR

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CIGRÉ Study Committee ReportSCA2October 19,
2008WinnipegClaude Rajotte, Hydro-Québec-TransÉ
nergie
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The Transformer Committee (A2)

• Scope Design, construction, manufacture and
  operation for all kinds of power transformers,
  including industrial , DC converters and
  phase-shift transformers and for all types of
  reactors and transformer components (bushing,
  tap-changer)
• In the past ( known as SC12 ) activities were
  focussed on design problems related to the rapid
  increase of rated voltage and power
• Today, the two Strategic Directions for A2 future
  activities are
• Services to Customers ( Reliability, Life
  management, Economics, Tutorials, ...)
• Technology Issues (Safety, New technologies and
  New concepts, Electrical environment,
  Pre-standardisation work, ...) 

Chairman Pierre Boss (CH)Secretary Claude
Rajotte (CA)
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WG completed recently

• WG A2.26 Mechanical condition assessment
  analysis of transformer windings using FRA
  Patrick Picher (CA)
• - Guidance for FRA,,
• - Compare different practices and propose and
  optimised practice- FRA interpretation,
  modelling, complementary methods
• WG A2.27 Recommendations for monitoring
  facilities -Paul Jarman (UK )
• - Review existing and developing condition
  monitoring systems and practice
• - Propose standardization
• - Make recommendations for the provision of
  sensors facilities or data from new transformers
• TF A2.30 Moisture in transformer - V. Sokolov
  (UA)
• - Moisture equilibrium and moisture migration
  within transformer insulation systems
• - Critical Temperature on Bubble Evolution of
  oil-immersed Transformer under overload condition
• - Considered new research works done in this
  field like - bound water- effect of acids on
  water in oil

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Present A2 WG

• WG A2.24 Thermal performances Ian Declercq (BE )
• - Fundamentals on thermal ageing
• - Ratings of new transformers - standardization
• - Practical applications for in service
  transformers - overload capability, reliability
  and economics
• WG A2.32 Copper sulphide in power transformer
  insulation Mats Dahlund (SE)
• - Created in response to several recent
  transformer failures due to cooper sulphide
• - Oil testing and specification issues CEI
  standard
• - Methods to identify units in danger
• - Recommendations for counter-measures to stop
  or retard the process
• - Improve understanding of the problem
• WG A2-33 -Fire Safety (A. Petersen/AU)
• - Avoidance of tank rupture
• - Precaution to fire victim
• - Precautions to fire origin

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Present A2 WG

• WG TF underway (suite)
• WG A2-34 Guide for Transformer Maintenance (C.
  Rajotte/CA)
• define a best practices list of periodic actions
  applied in service or with outage
• address advanced maintenance activities, such as
  oil additives, oil filtering, oil regeneration,
  and insulation drying
• human and material aspects of transformer
  maintenance, maintenance planning, maintenance
  tasks tracking, maintenance resources, cost
  references, level of competences required for
  different tasks, training, on-site repair, etc.
• WG A2-35 Experiences in service with new liquids
  (R. Martin/UK)
• - Physical, Chemical and Electrical properties of
  alternative fluids in comparison with Mineral oil
• - How the use of the alternative fluids impinges
  on equipment design
• Gather and review in service uses of the new
  fluids Where and how used Power and
  distribution transformers Review in-service
  concerns/needs,
• Review relevance of in service tests (Lab and
  field) to the new fluids as opposed to mineral
  oil
• Maintenance and retrofilling
• Reliability, longevity and the interaction of
  fluids with solid insulation. There is no
  Canadian member in this WG.

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Present A2 WG

• WG A2-36 Guide for Transformer Procurement
  Process (T. Breckenbridge / UK).
• -Review and update of the existing CIGRE A2
  documents on procurement
• -Taking into account the current market
  conditions and the new commercial pressures that
  customers operate under
• - Prepare a new guide for assessing the
  capability of transformer manufacturers that
  evaluates technical competence and experience
• WG A2-37 Transformer Reliability Survey (S.
  Tenbohlen/DE).
• Review all existing national surveys and study
  different practices (data collection,
  compilation, etc.)
• Discuss the differences and identify best
  practices
• Compile and present the information available in
  these national survey reports
• Make recommendations to improve the situation.
  There is no Canadian member in this WG.

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Present A2 WG

• WG A2-38 Transformer Thermal Modelling (J.
  Lapworth/UK).
• Describe the state of the art techniques in
  transformer thermal modelling to evaluate winding
  hottest spot as well as hot spots on other
  metallic parts
• Examples of advanced transformer modelling tools
• Examples of application of hottest spot direct
  measurement and best practices
• Advantages and limitations of these technologies
• Recommendation for standard improvement.
• Applicability of thermal modelling to revise old
  transformer thermal performance

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Present A2 JWG

• WG A2/B4.28 HVDC Converter Transformer Milan
  Saravolac (FR)
• WG started on recommendation of WG B4.04/A2
  Analysis of HVDC Thyristor Converter
  Transformers Performance
• Review Reliability Questionnaire
• Technical Specification for HVDC converter
  transformers
• Design Review Guide for HVDC converter
  transformers
• Test specifications
• JWG A2/C4.39 - Electrical Transient Interaction
  between Transformers and the Power System (A.da
  Costa Oliveira Rocha/BR)
• Assess and discuss the different types of
  electrical transient interaction between
  transformers and other components of the TD
  power system
• Discuss the general increase in transformer
  dielectric failures in the system.

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Other activities with liaisons

• WG D1-01 Impregnated insulation (L. Lundgaard /
  NO)
• TF D1-01-12 Oil maintenance -Insulating oil
  reclamation and and dechlorination (B.
  Pahlavanpour / UK
• TF D1-01-13 Furans for diagnostics (Marie-Claude
  Lessard / CA
• TF D1-01-14 Dielectric response diagnoses for
  transformer windings (S. Gubanski / SE).
• TF D1-01-15 Progress in DGA techniques and
  diagnoses (M.Duval / CA)
• TF D1-01-17 Oxidation Stability of Transformer
  Insulating Oils (I. Atanasova Höhlein / DE)
• WG C1-10 CIGRE Glossary (A. Popescu /RO W.
  Reinke / US)
• WG A3-22 Technical requirements for substation
  equipment exceeding 800kV (Dr. Hiroki Ito / JP)

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Recent CIGRE BROCHURES
Scope Ref Year Thermal aspects
96 1995 Static electrification
170 2000 Effect of particles
157 2000 Customer specifications 156 2000
Design reviews 204 2002 Short circuit
performance 209 2002 Life management of
transformers 227 2003 Economics of Transformer
Management 248 2004 Guide Transformer Data
Lifetime Management 298 2006 Mechanical Cond.
Assessment of Xfo Windings 342 2008 Recom. for
Condition Monitoring Assessment 343 2008 Moistur
e Equilibrium within Transfo. Insulation 349 2008

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A2 Tutorial External Events
Support to the Conf. on Transient Phenomena in
Large Electric Power Systems in Zagreb/Croatia
(April 2007) International Conference on Power
Transformers, May 30-31, 2007 -Torun, Poland
Workshop on Variable Frequency Diagnostics
Dielectric response and FRA, Stockholm, Sweden,
Sept. 2007 Conf. on Tfo Technology in Serbia
and Rumania, Sept 2007 Joint Colloquium SC
A2/D1 in Bruges, Belgium, October 2007
International Advanced Research Workshop on
Transformers, Vigo, Spain, October 2007
Matpost 07, Lyon/France, November 2007 CMD2008
Int. Conf. on Condition Monitoring and
Diagnostics, Beijing, China, April 2008
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Past SC A2 Sessions Colloquium
2004 Paris - Thermal Performances On-site
operations 2005 Moscow - Colloquium on
Transformers Reliability (Technical,
Economical and Strategic Aspects)
- New Development of electrical
transients on transformer
performances 2006 Paris - Transformers
Reliability, Technical, Economical and
Strategic Aspects -
New Development of electrical transients on 
transformer performances
- Phase-Shifter Transformers 2007 Bruges
-Guidance in new insulation liquids for
improvement on performance and
reliability -Life estimation of
transformers in service -Reactors and
related items 2008 Paris -Performance in
service of new insulation systems for transfo.
-Reliability and risk assessment of
transformers in service -Reactors
(shunt, shunt with regulation, series,
neutral)and related items
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Future SC A2 Sessions Colloquium
The next SCA2 Colloquium will be held in South
Africa in coordination with SC A3 (High Voltage
Equipment and B3 (Substations) during the period
August 17th-21st, 2009. The preferential
subjects are - Substation layouts - End of
Life Asset Management - Maintenance of Equipment
for Maximum Reliability For Paris 2010, the
preferential are - Catastrophic failure -
Transformer Life - Transformer Modelling