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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 allkinds of power transformers, including industrial , DCconverters and phase-shift transformers and for all types ofreactors and transformer components (bushing, tap-changer…)

In the past ( known as SC12 ) activities were focussed ondesign problems related to the rapid increase of ratedvoltage 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 • More than 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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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

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

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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

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

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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

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)

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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

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

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

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Present SC A2 Working Groups

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

IMPACT RISQUES

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7 XX XX %6

5 FORT

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3 XX MOYEN

2 XX XX

1 FAIBLE

0 1 2 3 4 5 6 7 8 9 PROBABILITÉ

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

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Present SC A2 Working GroupsJWG A2/D1.51: Improvement to Partial Discharge Measurements for Factory and Site Acceptance Tests of Power Transformers (S. Coenen/DE)

• Discussion and Comparison of given methods in international standards

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

Acceptance Tests

JWG A2/C4.52: High-frequency transformer models for non-standard waveforms (B. Gustavsen/NO)• 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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WG A2.53: Objective interpretation methodology for the mechanical condition assessment of transformer windings using Frequency Response Analysis (P. Picher/CA)

Present SC A2 Working Groups

JWG A2.54: Power transformer audible noise requirements (C. Ploetner /DE)

• Review of the state-of-the-art of quantitative interpretation methodologies.

• Use of high frequency transformer modelling, real case studies or a combination of both.

• Discuss the applications for such methodologies and make recommendations for best practices and possible standardisation.

• Description of basic sound development mechanisms -distinguish between no-load and load condition and cooling system.

• Development of sound level ranges for all three components per transformer class. 1Ɵ/3Ɵ/50Hz / 60Hz

• Summary information on sound mitigation (mounting, panels, enclosures, walls around units)

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Future activities

• Life extension• Efficiency• Phase Shifting Transformers• Effect of GIC

Possible future WG - under discussions

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Recent CIGRE BROCHURES

Scope Ref YearCopper 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 2014Copper Sulphide Long Term Mitig.&Risk asses. 625 2015

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Recent and Future SC A2 Sessions & Colloquium2013 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

2016 Paris Session - Advances in transformer diagnostic and monitoring- EHV / UHV and EHV DC / UHV DC Transformers and their components- Transformer windings

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Thank you for your attention

www.cigre-a2.org