The Advantages of using ester transformer fluids in Sub-Saharan Africa. Dr Russell Martin, November 2018

Size: px

Start display at page:

Download "The Advantages of using ester transformer fluids in Sub-Saharan Africa. Dr Russell Martin, November 2018"

Moris Waters
5 years ago
Views:

2 Agenda Usage and Definition of Ester Typical Applications Key advantages of using esters Fire Safety advantages of using esters Environmental Protection is enhanced by using esters Moisture Tolerance and Prolonging Asset Life Retrofilling with esters Esters in Power Transformers Esters in Tapchangers Financial advantages of using esters Conclusion

3 Usage of Ester Liquids Worldwide Established technology : SE > 40 yr ; NE ~ 20yr ~70% of the world uses ester technology Countries with Ester filled transformers

4 Applications of Ester Fluids Electrical Utility Power Distribution Retro-filling Wind Energy Offshore / Onshore Offshore Substation Oil & Gas Rail Traction / Trackside Underground Marine and Subsea Underground Mines Underground Hydro plants

5 M&I Materials - A world leader in ester transformer fluids Production & Storage

6 What are Esters? The term Ester describes a chemical linkage between an acid and an alcohol There are 2 types of Ester dielectric fluids Natural esters : made from plant seed oils Midel en 1204 from Rapeseed oil Midel en 1215 from soya oil Synthetic esters : are synthetically manufactured using carefully selected raw materials Midel 7131 Both types of esters are Fire Safe Environmentally friendly (Readily Biodegradable) Synthetic esters and more oxygen stable than Natural esters which need sealed/bagged applications

7 Esters for fire safety Flash Point Defined as temperature at which vapour ignites, but will not sustain burning when flame is removed Fire Point Defined as temperature at which vapour ignites and sustains burning for at least 5 seconds when source of ignition is removed Fluid Flash Point (ISO PMCC) Fire Point (ISO COC) Midel 7131 Synthetic Ester Midel en 1204/1215 Natural Esters 260 C 316 C >260 C > 350 C Mineral Oil 150 C 170 C

8 Esters - Ignition Resistance Mineral Oil 3 mins Mineral Oil 4 mins Synthetic Ester 3 mins Synthetic Ester 70 mins

9 Self Extinguishing Spray Test Equipment Setup

10 Mineral Oil Spray Test Video

11 MIDEL 7131 Spray Test Video

12 MIDEL en 1204 Spray Test Video

13 Fire Safety Advantages of Using K Class Fluids High degree of fire safety Fluids extremely difficult to ignite Very low risk of pool fires (none reported) Lower installation costs Possible insurance benefits

14 Ester Safety recognised by Insurance Companies Installation Guide FM Global Worldwide insurance company Significantly reduced clearances IEC Significantly reduced clearance for K-class fluid Lower fire protection requirements for indoor installations NFPA 70 (National Electrical Code) American standard No need for transformer vault for indoor installations <38kV

15 FM Global Guidance Outdoor Installation

16 FM Global Guidance Indoor Installation

17 Advantages of Reduced Separation Less space required for installation Reduces cost of land Allows more equipment in smaller area Ideal in urban areas Shorter cable runs from transformer to load Lower cabling cost Lower losses

Distribution Transformers (2012) Winning at the Eurovision Song Contest Customer:

18 Examples of Underground projects using ester fluid for fire safety Customer: Kraftwerke Oberhasli AG (KWO), Switzerland Application: 50MVA Converter and Distribution Transformers (2012) Winning at the Eurovision Song Contest Customer: Azerenergylle, Baku, Azerbaijan Application: 100kV 80MVA Underground Power Transformer (2012)

Transformers (2010) Power Transformer Installed Underground in an Environmentally Sensitive Location

19 Examples of Underground projects using ester fluid for fire safety Power Transformers for Underground Rock Stations Customer: Göteborg Energi Nat AB, Göteborg, Sweden Application: 135kV, 40MVA GSU Power Transformers (2010) Power Transformer Installed Underground in an Environmentally Sensitive Location Customer: Vattenfall AB, Stalon Hydropower Station, Sweden Application: 238kV 135MVA GSU Power Transformer (2004)

20 OXEA Case Study OXEA, part of the Oman Oil Company, is a leading chemicals manufacturer with operations around the globe. In 2017, OXEA s manufacturing plant in Oberhausen,Germany retrofilled 2 mineral oil filled distribution transformers with ester This increased fire safety and addressed environmental concerns. This mineral oil replacement reinforced the company s approach to safety and business continuity.

into the environment Is not detrimental to degradation of activated sludge in

21 Esters for Environmental Protection Readily Biodegradable Non-Toxic Recoverable and dispersible at sea using standard methods Non-Volatile - Will not evaporate into the environment Is not detrimental to degradation of activated sludge in biological treatment plants Natural esters have a lower carbon footprint than mineral oil

22 Comparative Biodegradation Rates

23 Advantages of Readily Biodegradable Fluids Safe for the environment Does not persist Cost Savings Possibility of reduced containment Reduced clean up costs for spills Potentially lower insurance premiums e.g. FM Global

24 Ester Moisture Tolerance Where Moisture Originates The atmosphere Can ingress through headspace in breathing transformers Through leaks in sealed units During maintenance Especially important in humid climates The paper As paper ages due to oxidation it releases water

25 Water in Cellulose Accelerates Deterioration Ref: H. Borsi Schering Institute

26 Ester Structure and Interaction with Water Water Structure Hydrogen bond Basic Ester Structure Hydrogen Bonding

27 Esters interaction with moisture Moisture Saturation Comparison Fluid Ester Groups Saturation 20 C Saturation 60 C Synthetic Ester ppm 4500ppm Natural Ester ppm 1900ppm Mineral Oil 0 55ppm 207ppm Silicone Liquid 0 220ppm 550ppm

28 Breakdown Voltage vs. 20 C. IEC 60156, 2.5mm gap

29 Extending Asset Life - IEC Kraft Paper Lifetime Ref: IEC Ed.1 Sept 2013

30 Paper Lifetime Enhancement Esters have the potential to keep cellulose drier, through absorption of water Similar moisture regulation mechanisms in both natural and synthetic ester Similar pressboard lifetime extension in long term study

31 Retrofilling using esters Retrofilling is the replacement of the fluid in the transformer Utilities get the benefit of Esters without buying a new transformer Retrofilling Mineral oil transformers with Esters will give: Increased fire safety Greater environmental protection Asset life extension

32 Esters in Power Transformers SYNTHETIC ESTER NATURAL ESTER High Voltage Rating Year High Voltage Rating Year 110kV 25MVA kV 15MVA kV 110MVA kV 200MVA kV 135MVA kV 8MVA kV 100MVA kV 25MVA kV 200MVA kV 40MVA kV 80MVA kV 40MVA kV (3) 240MVA kV 300MVA kV (4) 120MVA Development of synthetic and natural ester power transformers has happened in parallel The table shows a selection of the power transformers with synthetic and natural esters installed over the last 25 years

Esters in Large Power Transformers National Grid UK 3 x 400kV London Project Large scale project in a dense urban area Synthetic-ester design crucially delivered: Increased fire safety Fire

33 Esters in Large Power Transformers National Grid UK 3 x 400kV London Project Large scale project in a dense urban area Synthetic-ester design crucially delivered: Increased fire safety Fire suppression elimination Less complex containment system Lower overall project costs Substation size (m²) Civil construction Containment Drainage London Power Tunnels, Seven Sisters Road, public information leaflet, 2012

34 Esters in Large Power Transformers Vattenfall Letsi 433kV Generator Transformers Four single phase Generator Step Up units for hydro plant Rated 433kV 122MVA Synthetic ester chosen for fire safety and environmental reasons Transformers in service 2016

their tapchangers Having both the power transformer and

35 Use of Esters in OLTC MR, ABB & Huaming have approved M&I both Synthetic Ester & Natural ester For use in their tapchangers Having both the power transformer and the tapchanger filled with the same fluid is a great advantage

36 Cost Benefits of Ester Fluids Ester fluids bring benefits which can potentially cut installation costs Reduction in civil engineering costs due to higher level of fire safety Ability to place transformers closer to the load Simplification of fire extinguishing systems, which are costly to buy and maintain Simplification of bunding schemes due to biodegradability of esters Potential for more compact high temperature designs, which reduce shipping size and weight

37 Conclusion Synthetic and Natural esters are long established & trusted in the market Benefits Fire Safety Environmental Protection Moisture Tolerance and Asset Life Extension DGA Analysis commonly used Installation cost savings-fire suppression/oil containment Covered by International Standards Retrofilling existing mineral oil transformers Use in Large Power Transformers ( >400kV)

The Development of 400kV Class Synthetic Ester Transformers

The Development of 400kV Class Synthetic Ester Transformers Products of M&I Materials Ltd. Structure What is an ester? Industry trends for ester fluids History of esters in distribution and high performance