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Home My WebLink About20190924Avista to Staff Attach A - History of Transformers.pdfCoyote Springs 2 Transformer Update •December 19, 2007 Staff_PR_162 Attachment A Page 1 of 49 XFMR #1 •Mfg’d by Alstom –Gebze, Turkey 2001 •Cost $1.6M •Commissioned March 2002 •Failed catastrophically May 2002 –back feed only •Hydran did not give indication Staff_PR_162 Attachment A Page 2 of 49 XFMR #1 Failure May 6, 2002 Staff_PR_162 Attachment A Page 3 of 49 XFMR #1 Failure H2 bushing fire Staff_PR_162 Attachment A Page 4 of 49 XFMR #1 Failure Ruptured tank and oil leak Staff_PR_162 Attachment A Page 5 of 49 XFMR #1 Failure Ruptured tank and oil leak Staff_PR_162 Attachment A Page 6 of 49 XFMR #1 Failure Oil spill Staff_PR_162 Attachment A Page 7 of 49 XFMR #1 •Sent to Edison ESI for forensic inspection •XFMR #2 ordered from Alstom –Gebze, Turkey Staff_PR_162 Attachment A Page 8 of 49 XFMR #1 –Forensic June 2002 This image cannot currently be displayed. H3 winding Staff_PR_162 Attachment A Page 9 of 49 XFMR #1 -Forensic This image cannot currently be displayed. H3 winding entrance Staff_PR_162 Attachment A Page 10 of 49 XFMR #1 -Forensic This image cannot currently be displayed. H3 winding entrance lead Staff_PR_162 Attachment A Page 11 of 49 XFMR #2 •Failed impulse testing August 2002 •Retested and passed November 2002 This image cannot currently be displayed. Staff_PR_162 Attachment A Page 12 of 49 XFMR #2 –Test Failure This image cannot currently be displayed. H3 winding -impulse failure Staff_PR_162 Attachment A Page 13 of 49 XFMR #2 •Placed on pad at CS2 on December 17, 2002 •Shipping damage to core leg discovered by Alstom on December 18, 2002 •Shipped to Edison ESI for repairs by Alstom Staff_PR_162 Attachment A Page 14 of 49 XFMR #2 –Shipping Damage Staff_PR_162 Attachment A Page 15 of 49 XFMR #2 •Shipping damage (fifth leg of core) was repaired at Edison ESI by Alstom •Transformer placed on pad at CS2 (second time) on May 15, 2003 •Transformer was energized on May 31, 2003 •Coyote Springs 2 commissioned on July 1, 2003 Staff_PR_162 Attachment A Page 16 of 49 XFMR #2 •Transformer was fully operational for the next 6 months •Due to history, an aggressive DGA testing schedule was implemented •January 14, 2004 –DGA test was normal Staff_PR_162 Attachment A Page 17 of 49 XFMR #2 •January 15, 2004 –Buchholz alarm received •Decision was made to de-energize transformer and test •Hydran alarm was delayed Staff_PR_162 Attachment A Page 18 of 49 XFMR #2 -Hydran Readings 0 200 400 600 800 1000 1200 17:15 21:30 23:30 3:15 6:01 De-energized at 18:10 Peak 1016 ppm10 hours after alarmBuchholz Alarm at 17:15 Staff_PR_162 Attachment A Page 19 of 49 XFMR #2 -DGA Results •January 16, 2004 –DGA test -acetylene 84 ppm-ethylene 24 ppm -hydrogen 139 ppm-methane 25 ppm -CO 179 ppm-CO2 1005 ppm •DGA tests were repeated on January 21, 2004. Combustibles continued to increase… Staff_PR_162 Attachment A Page 20 of 49 XFMR #2 -Field Testing •Considerable electrical testing was performed (turns ratio, pf, megger, bushing pf, excitation current). Tests were inconclusive. •Transformer was drained and internally inspected. •Evidence of tracking was found in the vicinity of the H3 entrance lead. Staff_PR_162 Attachment A Page 21 of 49 XFMR #2 -Inspection Tracking on H3 Staff_PR_162 Attachment A Page 22 of 49 XFMR #2 •Decision was made jointly between Alstom (Areva) and Coyote Springs 2 to send the transformer back to the manufacturing plant in Gebze, Turkey for disassembly. Staff_PR_162 Attachment A Page 23 of 49 XFMR #2 –Disassembly Transformer in Gebze, Turkey Staff_PR_162 Attachment A Page 24 of 49 XFMR #2 -Disassembly Tracking on H3 Staff_PR_162 Attachment A Page 25 of 49 XFMR #2 -Disassembly Tracking on H3 HV insulation Staff_PR_162 Attachment A Page 26 of 49 XFMR #2 -Disassembly Staff_PR_162 Attachment A Page 27 of 49 XFMR #2 -Disassembly Staff_PR_162 Attachment A Page 28 of 49 XFMR #2 -Disassembly Hole in static ring Staff_PR_162 Attachment A Page 29 of 49 XFMR #2 -Disassembly H3 HV winding removal Staff_PR_162 Attachment A Page 30 of 49 XFMR #2 -Disassembly H3 HV insulation Staff_PR_162 Attachment A Page 31 of 49 XFMR #2 -Disassembly Burned insulation at braze Staff_PR_162 Attachment A Page 32 of 49 XFMR #2 •Alstom (Areva) agreed to rewind HV windings •Unit tested and returned to Coyote Springs; energized in August 2004 •Hydran sensor replaced March 2006 •Serveron online DGA monitor installed May 2006 Staff_PR_162 Attachment A Page 33 of 49 XFMR #3 -Spare •Siemens –Jundiai, Brazil awarded contract for $1.75M •Unit delivered November 2004 •Fully commissioned as spare Staff_PR_162 Attachment A Page 34 of 49 XFMR #3 -Spare Staff_PR_162 Attachment A Page 35 of 49 XFMR #3 -Spare Staff_PR_162 Attachment A Page 36 of 49 XFMR #2 •March 23, 2007 –Buckholz, Hydran and Serveron alarms •Unit removed from service •Diagnostic tests inconclusive •Internal inspection inconclusive Staff_PR_162 Attachment A Page 37 of 49 XFMR #2 –DGA March 23, 2007 Staff_PR_162 Attachment A Page 38 of 49 XFMR #2 -Change Out •Decision based on history, DGA, inability to find a field repairable problem •Siemens contracted for 500kV service crew •Siemens release to energize May 21, 2007 •Unit energized May 21, 2007 at 9:00 pm •Cost to swap -$500K •XFMR #3 operating normally since energized Staff_PR_162 Attachment A Page 39 of 49 XFMR #2 –Removal Staff_PR_162 Attachment A Page 40 of 49 XFMR #3 –Install Staff_PR_162 Attachment A Page 41 of 49 XFMR #3 –Install Staff_PR_162 Attachment A Page 42 of 49 XFMR #2 -Salvage •Decision based on history, cost and repair viability •On-site salvage and forensic completed in November 2007 •Forensic showed damage in H1 winding Staff_PR_162 Attachment A Page 43 of 49 XFMR #2 –Salvage/Forensic Staff_PR_162 Attachment A Page 44 of 49 XFMR #2 –Salvage/Forensic H1 lead Staff_PR_162 Attachment A Page 45 of 49 XFMR #2 –Salvage/Forensic H1 winding Staff_PR_162 Attachment A Page 46 of 49 XFMR #2 –Salvage/Forensic H1 lead collar Staff_PR_162 Attachment A Page 47 of 49 XFMR #2 -Salvage •Net salvage value -$300K •Insurance claim submitted for full replacement of spare •Insurance company witnessed forensic and has agreed unit is covered •Compensation still to be determined Staff_PR_162 Attachment A Page 48 of 49 XFMR #4 -Spare •Siemens –Jundiai, Brazil awarded contract November 2007 for $4.2M •Unit to be delivered June 2009 Staff_PR_162 Attachment A Page 49 of 49