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WG B1.25 Advanced Design Of Laminated Metallic Coverings. Minutes of the second meeting of WG B1-25 Stockholm (Kista) – 9&10 October 2007 1 pm – 12am. WG B1.25 Attendee. Matthias KIRCHNER Germany Giovanni POZZATI Italy Frank MIDDEL Netherlands
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WG B1.25 Advanced Design Of Laminated Metallic Coverings Minutes of the second meeting of WG B1-25Stockholm (Kista) – 9&10 October 20071 pm – 12am
WG B1.25 Attendee Matthias KIRCHNER Germany Giovanni POZZATI Italy Frank MIDDEL Netherlands Bjorn SANDEN Norway Johan KARLSTRAND Sweden Pierre MIREBEAU Convener
WG B1.25 – Documentation and reports (reminder) Website • http://www.cigre-b1.org/ • WG area • WG B1-25 • Password : "screen" for reading • pierre.mirebeau@nexans.com
WG B1.25 Agenda 1Welcome 2Examination / comments of WG documents : Last meeting’s minutes Annual report 3Updated recommendation : Table of content Content discussion 4Update on tests : Moisture penetration Screen contact resistance Bending test Thermal cycle test Longitudinal water penetration test Impact test Short circuit test Sidewall pressure test Corrosion test after impact or sidewall pressure test Adhesion strength of metallic foil Peel strength of overlapped metallic foil Any method of any need when taking into account the operation feed back ? 5Update on feedback : 6Date and location of the next meeting In conjunction with IEC WG 16, the day before. i.e. 1&2/04/08 .
WG B1.25 Welcome We thank our Swedish friend for his invitation and the perfect organisation of the meeting
WG B1.25 Examination / comments of WG documents : Last meeting’s minutes: The first meeting’s minutes are approved: see WEB pages of WG B1-25 • Annual report: • Presentationof the Working body and the outcome of the first two meetings to the SCB1 in OSAKA: see WEB pages of WF B1-25 • Two utility members would be useful in the WG: This will be asked for during SC B1 meeting in OSAKA, • Note : UK and France offered to present utility members • Matthieu Surdon from RTEwill be the French member • UK: to be nominated by national committee member (Steve Swingler)
WG B1.25 Updated recommendation table of content 11ForewordWB Form 1.1 Purpose of the Electra 141 update 1.2 Definitions Laminate covering definition 2The experience with cables with laminate coverings 2.1 The use, designs and market share 2.2 The system view 2.3 Conclusion 3 Recommendation : 3.1 Tests on cable 3.1.1 Development tests 3.1.2Requirements 3.1.2.1 Type test 3.1.2.2Sample test 3.1.2.3 Routine test 3.2 Test on cable system 3.2.1 Development tests 3.2.2 Requirements 3.2.2.1 Type test 3.2.2.2 Sample test 3.2.2.3 Routine test 4 Guide to use 4.1 As a function of laying conditions 4.2 As a function of customer requirements
WG B1.25 Discussion on content 1. Foreword Working Body Form Group No : WG B1.25 Name of the Convener : Pierre Mirebeau (FR) TITLE of the Group : Advanced Design Of Laminated Metallic Coverings Background: WG 21.14 published in 1992 "Guidelines for tests on high voltage cables with extruded insulation and laminated protective coverings". Numerous improvements appeared on laminated coverings since then in parallel with field experience. We now have a feed back relative to their use as a function of the length to be laid, the installation method (ducts, directly buried…), the environment, the design of the metallic screen (aluminium, copper wire screen + aluminium, copper…), the connection and grounding of the screen (single point, cross bonding, double point)… In parallel, new processes and new installation methods have appeared. o Terms of Reference: · To review and update the tests on cables with extruded insulation and laminated protective coverings taking into account the system view, i.e. the installation of accessories. Tests on cable, on accessories and on the system itself should be addressed, including the short circuit one · To issue a Guide to Use for non experts explaining what could be the different cable designs Scope of work : · Extruded cable systems only · AC cable systems only with a focus above 36 kV · Land cables Deliverables: The output should be an updated recommendation for tests on high voltage cables with extruded insulation and laminated protective coverings that includes a guide (for non-technical readers) with the aim to get customers to reference this guide. Moreover, the WG will provide an Electra article and a Tutorial for presentation at Cigre conferences and workshops. Created: 2006, Duration : 3 years Convener e-mail: pierre.mirebeau@nexans.com Members : Australia, Brazil, China, Finland, France, Germany, India, Italy, Japan, Norway, Sweden, United Kingdom, United States Approval by TC Chairman : Klaus Fröhlich Date : Jan. 9th, 2007
WG B1.25 Discussion on content 1.Foreword 1.1 Purpose of the Electra 141 update WG 21.14 published in 1992 "Guidelines for tests on high voltage cables with extruded insulation and laminated protective coverings". Numerous improvements appeared on laminated coverings since then in parallel with field experience. We now have a feedback relative to their use as a function of the length to be laid, the installation method (ducts, directly buried…), the environment, the design of the metallic screen (aluminium, copper wire screen + aluminium, copper…), the connection and grounding of the screen (single point, cross bonding, double point)… In parallel, new processes and new installation methods have appeared. This introduction shall be completed later, after discussions and outcome of inquiry
WG B1.25 Discussion on content: 1.Foreword 1.2 Definitions Laminate covering definition : A metallic laminate covering consist of several layers of plain (not corrugated) metal and plastic materials bonded together to get a special set of properties : bending ability, radial watertightness. It can be used to carry the capacitive, circulation and short circuit currents, according to the cable system design. Note: This definition is to be approved by the SC B1 in OSAKA after the WG meeting in Stockholm
WG B1.25 Discussion on content 2. Experience • 2. The experience with cables having laminate coverings • 2.1 The use, designs and market share • Make a table with designs, and comments (tests…) by countries • Length in use and time, voltage, experience • Proportion versus other designs. • Different type of screens in use, trend.
WG B1.25 Discussion on content 2. Experience • 2.2 The system view • The following items shall be considered: • Type of accessories. • Inclusion of system tests in standards • Short circuit tests with accessories • Sealing against water and corrosion at the accessories • Designs to be avoided (ex.: lapped copper tape under one side coated laminate – or no connection between wires and metallic foil at the accessories). • Types of laying and grounding. • Stiffness (no issue actually)
WG B1.25 Discussion on content 2.Experience 2.3 Conclusion …
WG B1.25 Discussion on content 3. Recommendations Full members not present at the second meeting and corresponding members are invited to give their comments and inputs to the items of chapter 3(Recommendations), if possible before next meeting, 1 and 2 April 2008, so that we can integrate them into the report of second meeting
WG B1.25 Discussion on content 3. Recommendations • 3. Recommendations • 3.1. Tests on cables • 3.1.1 Development tests • Bending test :OK. Question : what about a bending on 20 (D+d) ? • Thermal cycle test: fatigue proven to be not an issue (Electra 141, but decrease of peeling strength in case of bad design test replaced by ageing test and peeling measurement). Get a proposal by next meeting. • Longitudinal water penetration test. Refer to IEC • Impact test. If feedback is OK, Electra 141 to be considered in case of a buried cable system. If feedback show issue to reconsider, may be 2 classes could be considered : standard type (5kg weight dropped from 1m height on cable sample ) and reinforced test as for French standard:(27kg weight dropped from 27cm height on cable sample, several times on the same place).
WG B1.25 Discussion on content 3. Recommendations3.1. Tests on cable 3.1.1 Development tests (continued) • Short circuit test short circuit on the systemto be considered • Sidewall pressure test See Italy and Japan to know if it is discriminating between good and bad cables; if not, this test is useless because it was not used during 10 years and there was no practical problem. • Corrosion test after impact or sidewall pressure test preconditioning is not necessary. Test on fresh cable is enough. • Adhesion strength of metallic foil. Proposal is to recommend a peel strength of 1.5N/mm in stead of 0.5 N/mm. Test at room temperature. • Proposal: introduce an adhesion strength test at high temperature before and after ageing. • Members have to check it
WG B1.25 Discussion on content 3. Recommendations3.1. Tests on cable 3.1.1 Development tests (continued) Moisture penetration: HD 620 part 6J. appendix F.4. Determination of the water permeability coefficient of the non-metallic sheath. This test is to be performed within the WG on a cable with overlapped laminate to make clear whether it is useful to recommend it. PM will make the test on a HV cable next meeting Screen contact resistance (under development in Electra 141) addressed by the PD test at the end of the type test. Made initially for designs where the wires are not connected to the metallic foil at the accessories. Now every people makes the connection in HV. The test is not needed any longer.? Fatigue : to be discussed when receiving all the following papers: B1-111 (on WEB site), ELT 140 (Johan), CS9 (draft G on WEB site) , IEEE PES 96 nb1 and IEEE PES 99 nb6 IEEE PES 96 nb1 (Pierre Argaut), JICABLE 03 p A-1-5 from J Power (Pierre) and ICEA S -108 - 720 (Bruno). Spike test : Ask to Steve or Vic whether this test has failed in practice. For the attending members, it is useless. Abrasion test
WG B1.25 Discussion on content 3. Recommendations3.1. Tests on cable 3.1.2 Requirements (continued) 3.1.2 Requirements(not discussed) 3.1.2.1 Type test 3.1.2.2Sample test 3.1.2.3 Routine test
WG B1.25 Discussion on content 3. Recommendations3.2. Tests on cable system 3.2.1 Development tests • 3.2. Tests on cable system • 3.2.1 Development tests • Short circuit tests with accessories • Sealing against water and corrosion at the accessories • Thermal cycle test • Thermomechanical test 62067 addressed in prequalification test • 60840
WG B1.25 Discussion on content 3. Recommendations3.2. Tests on cable system 3.2.2 Requirements 3.2.2 Requirements(not discussed) 3.2.2.1 Type test 3.2.2.2Sample test 3.2.2.3 Routine test
WG B1.25 Discussion on content 4 Guide to use 4. Guide to use(not discussed) 4.1 As a function of laying conditions 4.2 As a function of customer requirements
WG B1.25 Discussion on content 5 Update on feed back • Frank will prepare asap a draft for a feedback inquiry to be addressed • to national committees (to be discussed during next meeting) • Length in use and time, voltage • Proportion versus other designs. • Evolution in cable design with laminate covering • Different type of screens in use, trend. • (Cable manufacturer can answer to that) • Reported faults • Which accessories design and evolution ? • Quality issues fault statistics, location cable or accessory ?