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Electrical Oil Services Life of A Transformer Seminar Dublin 2016

Electrical Oil Services Life of A Transformer Seminar Dublin 2016. On-site Options for Transformer Insulation Management. History Pressures on utilities and generators Looking after your paper insulation (water & acidity) Other parameters Take action – or not? In-situ treatment.

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Electrical Oil Services Life of A Transformer Seminar Dublin 2016

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  1. Electrical Oil Services Life of A Transformer Seminar Dublin 2016

  2. On-site Options for Transformer Insulation Management • History • Pressures on utilities and generators • Looking after your paper insulation (water & acidity) • Other parameters • Take action – or not? • In-situ treatment

  3. Standards referred to…BS148:1932 – 2009 – today known as “Reclaimed mineral insulating oil for transformers and switchgear – Specification”IEC60296:2012 – Unused mineral insulating oils for transformers and switchgearBS5730 / IEC60422 – Mineral insulating oils in electrical equipment – Supervision and maintenance guide

  4. Electrical Oil ServicesSome History

  5. A Little History Before Nationalisation 1926 Central Electricity Board 1947 British Electricity Authority 1954 Central Electricity Authority 1957 Central Electricity Generating Board 2000 Privatisation

  6. In 1941 “Unused Oil” could be delivered with a TAN Of 0.2mgKOH/g (measure of acidity neutralisation) Today the limit is just 0.01mgKOH/g (IEC60296:2012)

  7. A transformer purchaser could specify either “Class A” Or “Class B” insulating oil, depending on how much sludge He was prepared to put up with

  8. Electrical Oil ServicesPressure on Utilities and Generators

  9. Pressures on utilities(Distribution Network Operators) Privatisation of the CEGB Harmony with Europe Reduced build quality Professional Purchasing OFGEM Regulatory review Extend asset life Spending restrictions Value for consumer

  10. Pressures on Generators Privatisation of the CEGB Harmony with Europe Reduced build quality Professional Purchasing “Dash for Gas” 15 year life of a transformer Base load – 2 shifting Corrosive sulphur

  11. Electrical Oil ServicesLooking after your Paper Insulation (water and acidity)

  12. Looking after your paper insulation(Water) Cellulose loves water Insulation is dried in the factory Site drying is costly and lengthy Don’t let your transformer get wet

  13. How much water is in a transformer? 145MVA, 132kV HSPT GSU Tx Oil volume 34,704 litres Water content 23ppm at 50ºC Weight of oil = 0.87x34,704 litres = 30,019kg (paper = 3,019kg) Water in oil = 34704 x 23ppm/10⁶ Or ……0.8 litres in the oil Assuming equilibrium conditions

  14. From a typical paper/oil equilibrium chart 23ppm at 50°C equates to 2.3% water in paper Assuming weight of paper = 10% weight of oil Then Water in paper = 3,019kg x 2.3% = 69.4 litres That’s over three 25 litre cans of water!

  15. Install some kind of molecular sieve • Attention to breathers • Fix leaks • Dry air when oil is out • Don’t leave covers off New transformers are dried to 0.5% in the factory

  16. Looking after your paper insulation(Acidity) No such thing as an UNINHIBITED OIL Oxidation of oil leads to acid formation Acid attacks paper Transformer life is governed by the paper strength - maybe Permanent damage begins around 0.1mgKOH/g

  17. Electrical Oil ServicesOther Parameters

  18. And Other Parameters? • Dielectric Dissipation Factor (DDF) • Resistivity • Interfacial Tension • Breakdown Voltage

  19. Electrical Oil ServicesTake Action – or Not

  20. What next? What do these oil test results mean? Should I do anything?

  21. Importance of the transformer? Other DGA trends? Availability of spares? Should I do anything? Remaining paper “life”? Lead time for replacement? Opportunity to do other work?

  22. BSEN 60422:2013

  23. You could decide to take no action

  24. Electrical Oil ServicesIn-Situ Treatment

  25. BSEN 60422:2013

  26. A“wet” transformer?

  27. Oil Change For acidity?

  28. In-Situ Regeneration • Treats the insulation system • “Deep Cleaning” effect • Removes oxidation products • Tool for helping extend life • No outage necessary • Less stress on paper insulation • DBDS removed • Inhibitor added at the end

  29. Site Operation(On-load) Primary degassed loop Recondition the oil Admit oil to adsorbtion beds Reactivate beds Repeat till finish Add inhibitor

  30. 90MVA • Installed 1963 • 38,710 Litres of oil • DP of paper 500 • Acidity 0.28mgKOH/g • IFT of 13 • DDF 0.063mN/m • No history of faults • DGA “normal” for age 132kV DNO Transformer (OFGEM)

  31. 60MVA • Installed 1959 • 40,915 Litres of oil • DP of paper 523 • Acidity 0.27mgKOH/g • IFT 13 • DDF 0.072 • No history of faults • DGA “normal” for age 132kV DNO Transformer (OFGEM)

  32. 10MVA • Installed 1959 • 17,000 Litres of oil • DP of paper 420 • Acidity 0.24mgKOH/g • IFT 22 • DDF 0.23 • No history of faults • DGA “normal” for age 66kV Steel Works Transformer

  33. Electrical Oil Services General EnquiriesTel:+44( 0)845 602 1003www.eosl.co.uk

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