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CONSEIL INTERNATIONAL DES GRANDS RESEAUX ELECTRIQUES

INTERNATIONAL COUNCIL ON LARGE ELECTRIC SYSTEMS

STUDY COMMITTEE A2 TRANSFORMERS

Presentation of CIGRE activities

on 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

Tra

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tech

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log

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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 A2.42 - Guide on transformer Transportation (A. Mjelve/NO)

• Typical conditions/forces during transport

• Specifications and design review

• Requirements on transportation issues

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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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 A2.49: 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

9

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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Present SC A2 Working Groups

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 Groups

JWG 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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WG A2.55: Life Extension of oil filled Transformers and Shunt

Reactors (P. Mueller/CH)

Present SC A2 Working Groups

JWG A2.56: Power transformer efficiency (Zarko Janic/DE)

• Define means to extend service life of a

unit which is aged but in good enough

condition while ensuring the required level

of reliability at a targeted cost;

• Mitigation solutions to keep a failing unit

in service until a planned replacement.

• Economic and environmental impact of regulations on efficiency

• Transformer losses and strategies for their optimization

• Loss level specifications and loss evaluation used in tenders by utilities

• Experience with energy efficiency improvement, regulation and technology.

• Impact of higher efficiency on transportability of transformers

• Cost/benefit analysis for further efficiency improvement

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WG A2.57: Effects of DC Bias on power transformers (D. Susa/NO)

Present SC A2 Working Groups

• State of the art (phenomena, sources, application to transformer, case

studies, scenarios)

• Effect on power transformers (harmonic generation, VAr

consumption, noise, losses, temperatures/overheating, failure modes)

• Calculations, modelling, model verification

• Requirements for transformer specification and design review

• Methods to prove the withstand capability

• Design and technology susceptibility

Recent CIGRE SC A2 BROCHURES

Scope Ref Year

Transformer Thermal Modelling 659 2016

Technology & Util. of Oil Insul. HV Sh. Reactors 655 2016

Oil conductivity under DC condition 646 2016

Transformer Reliability Survey 642 2015

Guide on Transf. Intelligent Condition Monitoring 630 2015

Copper Sulphide Long Term Mitig.&Risk asses. 625 2015

Transient Interac. Transformers&Power System 577 2014

Guide for Specifications 528 2013

Guide for Design Review 529 2013

Guide for Factory Capability Assessment 530 2013

Guide for Fire Safety 537 2013

Guide on Transformer Maintenance 445 2011

HVDC Tr. – Test, ageing, reliability in service 406 2010

HVDC Tr. – Guidelines for design review 407 2010

Experience in service with new insulating liquids 436 2010

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Recent and Future SC A2 Sessions & Colloquium

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

2017 Cracow Colloquium

Subjects to be determined

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Thank you for your attention

www.cigre-a2.org