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CONSEIL INTERNATIONAL DES GRANDS RESEAUX ELECTRIQUES INTERNATIONAL COUNCIL ON LARGE ELECTRIC SYSTEMS

STUDY COMMITTEE A2 TRANSFORMERS

Presentation of CIGRE activitieson Power Transformers

C. Rajotte (CA)Chairman SC A2 "Transformers"

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The Transformer Committee (SC 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's SC A2 Key Domains

Chairman: Claude Rajotte (CA)Secretary: Patrick Picher (CA)

Design, manufacturing

& testing

Specifications, procurement &

economics

Operation, reliability, safety & environment

Maintenance, diagnostics, monitoring,

& repair

Life cycle

Tran

sfor

mer

tech

nolo

gy

Transformer utilisation

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Present SC A2 Activities

• 24 regular members• 19 observer members• 10 WG's and 5 JWG's• Almost 350 experts from more than 40

countries• 5 AG’s

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Present SC A2 Working Groups

WG A2-37 Transformer Reliability Survey(S. Tenbohlen/DE)

• Review all existing national surveys and study different practices ; identify best practices

• Compile and present the information available in these national survey reports

• Make recommendations to improve the situation

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 application of hottest spot direct measurement and best practices

• Recommendation for improvement of standards

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WG A2.40 - Copper sulphide long-term mitigation and risk assessment (J. Lukic/RS)

• Method, tools and diagnostic• Metal passivator stability and efficiency• Efficiency of existing on-site oil treatment

Present SC A2 Working Groups

JWG A2/D1.41 - Oil conductivity under DC condition(A. Küchler/DE)

• Started under recommendation of WG A2/B4.28

• Review techniques and standards for measurement of conductivity of liquids

• Suggestions for new standards

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WG A2.42 - Guide on transformer Transportation (A. Mjelve/NO)• Typical conditions/forces during transport• Specifications and design review• Requirements on transportation issues

Present SC A2 Working Groups

WG A2.43 Transformer bushings reliability (A. Mikulecky/HRvatska)

• Bushing failure definition • Failure mechanisms for OIP, RBP, RIP• Bushings failure rate • Predicted life time, maintenance,

diagnostic

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WG A2.44 – Transformer IntelligentCondition Monitoring (C. Dupont/BR)• Conversion of data to relevant information• Demonstration of benefits• Hardware/software/data integration -20

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20

30

40

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Rai

n cu

mul

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e (m

m)

Tg(%)

Time (hours relative to 2008:05:29-0H00 local time)

Present SC A2 Working Groups

WG A2.45: Transformer Failure Investigation and post-mortem Analysis (M.C. Lessard/CA)• Important information to collect• Availability and significance of design data• Documentation during the dismounting • Paper sampling: how, where, precautions

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JWG A2/D1.46: Field experience with transformer solid insulating ageing markers (R. Mertens/BE)• Field cases: correlation between chemical markers and DP• Design information relevant to ageing markers models• Consideration of operation and maintenance records• Influence of oil sampling conditions (ex: temperature)

Present SC A2 Working Groups

JWG D1/A2.47: New frontiers of Dissolved Gas Analysis (DGA) interpretation for power transformers and their accessories(M. Duval/CA)

• Review progress in the field of DGA • Significance of CO, CO2 and CO2/CO for detecting paper involvement in faults• Case studies and suggestions for typical problems and actions initiated by DGA

interpretation

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WG A2.48: Technology and utilization of Oil Insulated High Voltage Shunt Reactors ((S.RyderS.Ryder/UK)/UK)

Present SC A2 Working Groups

• Specification, design, noise• Type/routine tests and criteria• Reliability in service, failure mechanism and investigations• Operation, condition assessment, monitoring, DGA, etc.

WG A2.49: Condition Assessment of Power Transformers (P. Cole/AU)

• Review existing CIGRE documents and literature • Determine key parameters and how these parameters

can be combined to determine health index• Consideration should be given to both

deterministic and probabilistic methods.• Provide details of health indexes/condition

assessment tools currently in use and provide examples of applications

IMPACT RISQUES

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8 XX ÉLEVÉ

7 XX XX %6

5 FORT

4

3 XX MOYEN

2 XX XX

1 FAIBLE

0 1 2 3 4 5 6 7 8 9 PROBABILITÉ

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WG A2.50: : Effect of the distributed energy sources and consequent Effect of the distributed energy sources and consequent induced reverse power flow (step up) on transmission and induced reverse power flow (step up) on transmission and distribution transformersdistribution transformers (J.C. Riboud/FR)(J.C. Riboud/FR)

Present SC A2 Working Groups

• Effect of step up operation on transformers that were not designed for this purpose.

• Effect on flux density, temperature rise, noise and other performances

• Possible tap changer control problems• consequences for core flux and voltage regulation

JWG A2/D1.51: : Improvement to Improvement to Partial Discharge Measurements for Partial Discharge Measurements for Factory and Site Acceptance Tests of Power TransformersFactory and Site Acceptance Tests of Power Transformers (S. (S. CoenenCoenen/DE)/DE)

• Discussion and Comparison of given methods in international standards

• Discussion and Evaluation of alternative methods• Recommendations for improved PD Factory/Site

Acceptance Tests

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JWG A2/C4.52: : HighHigh--frequency transformer models for nonfrequency transformer models for non--standard waveformsstandard waveforms ((B. B. GustavsenGustavsen/NO/NO))

Present SC A2 Working Groups

• Provide guidelines and recommendations for the generation of transformer models for simulation of high-frequency transient overvoltages that can occur in actual service.

• Define minimum requirements that models supplied by manufacturers to customers must comply with for including the transformer model in network studies.

• Provide benchmark examples of models applied in simulation of transformer-network transient interactions using white-box and black-box models.

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Future activities

• FRA Interpretation• Phase Shifting Transformers• Effect of GIC• Transformer Typical/Minimum Audible Noise• Efficiency• Life extension

Possible future WG - under discussions

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Recent CIGRE BROCHURES

Scope Ref YearMechanical Cond. Assessment of Xfo Windings 342 2008Recom. for Condition Monitoring & Assessment 343 2008Moisture Equilibrium within Transfo. Insulation 349 2008Copper Sulphide in Transformer Insulation 378 2009Thermal Performances 393 2009HVDC Tr. – Test, ageing, reliability in service 406 2010HVDC Tr. – Guidelines for design review 407 2010Experience in service with new insulating liquids 436 2010Guide on Transformer Maintenance 445 2011Guide for Specifications 528 2013Guide for Design Review 529 2013 Guide for Factory Capability Assessment 530 2013Guide for Fire Safety 537 2013Transient Interac. Transformers&Power System 577 2014

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Recent and Future SC A2 Sessions & Colloquium2012 Paris Session- Transformers in the network of the future- Transformer Eco design / Eco use- Transformer magnetic circuit

2013 Zurich Colloquium (with SC C4)- Interaction between transformer and the Power System- Experience with the use of Phase-Shifting transformers- Network planning in the context of an ageing transformer fleet

2014 Paris Session - Best practices for transformer asset management- Transformers for specialized applications- Field experience with the use of non-conventional materials and technologies

2015 Shanghai Colloquium- EHV/UHV and EVHDC/UHVDC Transformers and its components - Equipment technologies for substations of the future and Smart Grid - in

collaboration with SC A3 and SC B3- Making the Best use of the Existing transformer fleet

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Thank you for your attention

www.cigre-a2.org