CIGRE WG C4.305 . PRACTICES IN INSULATION COORDINATION OF MODERN ELECTRIC POWER SYSTEMS AIMED AT THE REDUCTION OF INSULATION LEVELS WG Composition: WG Convenor: A. S. TELENTO (Hr) WG Secretary: S. MALGAROTTI (It) Total number of Members (Reg.+ Corr.) 20 Number of Regular members: 12 Number of Corresponding members: 8 Number of members from industry (utilities): 8 Number of members from industry’s institutes: 6 Number of members from universities (Edu., R&D): 2 Number of members from consulting companies: 4

Technical Committee meeting, September 1st, 2012 - Paris CIGRE WG C4.305 Number of countries represented: Total number: 12 Number of countries from various continents: Europe: 9, South America: 2, North America: 1 Asia, Africa, Australia: 0 (no participants) Conclusion: Countries from non-included continents are expected to be included in WG Survey and WG work (e.g. Japan, China, India, RSA…) Members of SC C4 are kindly requested to act in that direction. . WG Title matters: Original Title proposed in 2008 was: Insulation Coordination Practices and Tendencies in Modern EPS Changed Title (made by former SC Chairman C.A. Nucci in 2009): As in Title of this presentation – Consequences: Scope is focused to Ins. Level reduction – it changes to some extent the Scope of WG New slight change: Insulation Coordination Practices in Modern EPS aimed at the reduction of Ins. Levels (change in sequence of first three words) – that gives more stress in title on IC discipline Technical Committee meeting, September 1st, 2012 - Paris

Technical Committee meeting, September 1st, 2012 - Paris CIGRE WG C4.305 WG Timeline (1): Proposal of new WG given at the beginning of 2008 Date of approval: Signed by TC Chairman at the end of Nov. 2009 Information received by WG Convenor at the end of 2009 Beginning of WG work in the middle of 2010 (no sufficient answers received before spring 2010 from experts interested to work as WG members) Starting Dates: First informal meeting in Zagreb, Croatia, April 2010 First official WG Meeting in Paris, August 26, 2010 (14 participants) Second official WG Meeting, Rio de Janeiro, April 12, 2011, hosted by ONS and Mr. Dalton Brasil (7 participants) Third official WG Meeting: Paris August 28, 2012 (8 participants) Fourth official WG Meeting: Paris, August 27, 2014 Totally: 4 WG Meetings and additional 3 informal meetings in Zagreb have been held Number of Internal Working Documents (IWD) discussed and dispatched among WG Members: 22 (IWD 1 – IWD 22). Technical Committee meeting, September 1st, 2012 - Paris

CIGRE WG C4.305 WG Timeline (2): In 2013 WG Meeting was planned in Zuerich, but was not held due to unexpected infeasibilness of WG Convener. Details have been given to current SC C4 leadership. Due to same reason activity of WG 305 was slowed down or stopped for about 18 months (up to middle of 2014). Low-level intensity work in mentioned period (2013 to middle of 2014) was limited to the following: - exchange of some new IWDs among WG Members - inclusion of few new WG Members (e.g. A. Xemard, V. Larin etc.) - preparations for quick finishing of WG work in period after Paris Session 2014, etc. Expected date of submitting Final Report to SC Chairman: Final report will be submitted about half a year after Paris Session 2014, i.e. in spring 2015, after processing WG Survey on IC Practice .

CIGRE WG C4.305 WG Timeline (3): Graphical presentation of events in WG formation and work: . First idea The first Approval of on new informal new WG by First part of work o WG C4.305 Period of Second part of WG given Meeting TC Chairman forced break of WG 305 work on CIGRE on new WG at the end of WG C4.305 work and Final Report Symposium in Cavtat, year and after submission to in Zagreb, Croatia 18 months of SC Chairman Croatia submitting WG request _↑__₀____↑_₀_____↑₀____↑₀↑₀↑₀₀↑₀ 2008 2009 2010 2011 2012 2013 2014 2015 LEGEND: Thin line __ : Development of idea of new WG, Long period of WG approval by TC Red arrow  : Period of active work of WG with regular WG Meetings White arrow  : Period of inactivity or low intensity work Vertical arrow ↑: WG Meetings

TABLE OF CONTENTS 0F NEW CIGRE BROCHURE - TB WG C4.305 CIGRE WG C4.305 TABLE OF CONTENTS 0F NEW CIGRE BROCHURE - TB WG C4.305 Technical Committee meeting, September 1st, 2012 - Paris

CIGRE WG C4.305 Highlights of Recent Activity (1) Survey forms for gathering world-wide practice in IC consist of: I System parameters: IV Withstand voltages: Operating voltages  Transformers Neutral earthings  Switching equipment Design altitudes  Substation insulation II Overvoltage determining parameters:  Line insulators Lightning activity (GFD) V Pollution parameters: Transmission towers configuration  Class (ESDD, NSDD) Substation size and configuration  Creepage distances Capacitor banks and circuit breakers VI Insulation failure rates: Maximum overvoltages in system  Experienced data III Surge arrester application:  Acceptable levels Ratings VII Insulation level tendency Locations  Reductions

CIGRE WG C4.305 Highlights of Recent Activity (2): Example of diagram in textual part of Brochure:

CIGRE WG C4.305 Future activities: Despatch of survey forms to power utilities and countries: through WG C4.305, through SC C4 Members, NCs Cigre etc. Term: September 2014 Filling of survey, with possible help of WG or SC Members Term: till end of 2014 Gathering and processing data from world’s survey Term: the first quarter of 2015 Despatch of TB C4.305 Report to SC Chairman till June 2015 Inclusion of SC C4 in work of this WG, generic to part of SC C4: Letter of recommendation of SC C4 Chairman, approval of proposal of Letter: in September 2014 RM and OM of SC C4 are expected to help in interactive work with utilities and countries (such duty arises from SC Rules) SC Rule 5.5 “… processing of questionnaires issued by SC”

Thanks for your Attention! Special Thanks for your very kind Assistance to this Project! CIGRE WG C4.305 Technical Committee meeting, September 1st, 2012 - Paris