Presentation of CIGRE activities Chairman SC A2 "Transformers" 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"

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 Design, manufacturing & testing Specifications, procurement & economics Operation, reliability, safety & environment Maintenance, diagnostics, monitoring, & repair Life cycle Transformer technology Transformer utilisation Chairman: Claude Rajotte (CA) Secretary: Patrick Picher (CA)

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

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

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)

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

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

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.

Present SC A2 Working Groups WG A2.53: Objective interpretation methodology for the mechanical condition assessment of transformer windings using Frequency Response Analysis (P. Picher/CA) 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. JWG A2.54: Power transformer audible noise requirements (C. Ploetner /DE) 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)

Present SC A2 Working Groups WG A2.55: Life Extension of oil filled Transformers and Shunt Reactors (P. Mueller/CH) 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. JWG A2.56: Power transformer efficiency (Zarko Janic/DE) 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

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

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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