New EasyDry® transformer bushings Holger Hoffmann, Area Sales Manager MICAFIL Bushings, Johannesburg, May 2013
The paper-free solution
© ABB Group May 8/ 9, 2013 | Slide 2
Transformer condenser bushings
ABB recognized customer needs for a new bushing technology that would…
…preserve the safety and performance benefits of the traditional RIP bushings
oil-free and fully dry explosion proof and fire resistant high thermal strength, temperature class 120°C low dielectric losses partial discharge free excellent mechanical strength transportation, storage and assembly at any angle practically maintenance free
Why a new technology?
© ABB Group May 8/ 9, 2013 | Slide 3
Transformer condenser bushings
…while providing new customer benefits like
significantly easier and more economic long-term storage
easier and simpler bushing handling during transport, assembly and disassembly
shorter purchasing cycles optimised value for money less capital bound for maintenance of strategic
reserve/ stock
Why a new technology?
© ABB Group May 8/ 9, 2013 | Slide 4
Transformer condenser bushings
ABB utilized our vast experience in high voltage technology Corporate Research Centers in:
Switzerland, Sweden, Poland, India Bushing production expertise in:
Switzerland, Sweden, USA and Brazil Cutting-edge simulation tools for epoxy and silicone
molding process optimization Design for assembly methodology and production process
optimization (single piece flow)
How did ABB develop the new technology?
© ABB Group May 8/ 9, 2013 | Slide 5
Transformer condenser bushings
The new bushing technology is called
Resin Impregnated Synthetics (RIS)
The bushing product family is called EasyDry ®
How the new bushing technology is named?
© ABB Group May 8/ 9, 2013 | Slide 6
Transformer condenser bushings
RIS Field grading: Al-foils Insulation material: Filled epoxy resin Spacer material: Synthetic fabric
RIP Field grading: Al-foils Insulation material: Epoxy impregnated paper Spacer material: Paper
RBP Field grading: Al-foils Insulation material: Epoxy coated paper Spacer material: Paper
OIP Field grading: Al-foils/conductive ink Insulation material: Oil impregnated paper Spacer material: Paper
RIS Technology – the next step in bushing technology!
© ABB Group May 8/ 9, 2013 | Slide 7
RIS Condenser bushing
Compact and light bushing design Completely free of oil and paper Avoidance of moisture absorption Elimination of external insulator
components and filler material Superior mechanical, thermal and
electrical properties Same field grading as with RIP
bushings
What is the technical achievement?
© ABB Group May 8/ 9, 2013 | Slide 8
RIS Condenser bushings
Condenser core is wound out of synthetic fabrics
Al-foils used as condenser layers inside the wound core
Condenser core is impregnated with filled epoxy resin and molded into final shape
Silicone sheds are molded directly onto the condenser core
Final assembly of shielding electrode etc.
Routine testing
What are the main manufacturing steps?
© ABB Group May 8/ 9, 2013 | Slide 9
RIS Condenser core materials
Synthetic fabric prevents condenser core from humidity uptake
Open structure of synthetic fabric allows to use filled epoxy resin for impregnation
Inorganic mineral fillers yield to excellent mechanical, electrical and thermal properties of the epoxy resin condenser core
Synthetic fibers and epoxy resin
© ABB Group May 8/ 9, 2013 | Slide 10
RIS Condenser core production
Condenser Core based on synthetic fibers is molded into final shape
Time intensive drying is not needed anymore
Mechanical shaping (milling) is not necessary
Humidity uptake is physically limited
Minimized manufacturing process steps
© ABB Group May 8/ 9, 2013 | Slide 11
RIS Technology
Humidity in condenser core increases dissipation factor
Stable dissipation factor means no humidity uptake
Used RIS materials have very low saturation level
Highest bushing safety and reliability in all climatic environments
Significant operational advantage no humidity uptake
0
0.5
1
1.5
2
2.5
3
0 50 100 150 200
RIS
RIP
Dissipation factor as function of storage time Dissipation factor [%]
Storage time [d]
Results for Test at 40°C / relative humidity of 95% Source: ABB Switzerland Ltd.
© ABB Group May 8/ 9, 2013 | Slide 12
RIS Technology outdoor silicon insulation
Silicone sheds are directly molded on condenser cores
Minimal number of interfaces between different materials
Lowest material consumption
Silicone molding process is done inhouse
Inhouse process control for entire bushing
Dependence on external suppliers is significantly reduced
Process long term proved for different ABB high voltage products
Directly molded on condenser core
© ABB Group May 8/ 9, 2013 | Slide 13
RIS Technology
1. Copper terminal
2. Clamp to fix terminal
3. Silicon outdoor insulator
4. Mounting flange
5. Measuring tap
6. Condenser core
7. Extension for current transformer
8. End shield
EasyDry® product family
5
3
2
1
8
4
7 6
© ABB Group May 8/ 9, 2013 | Slide 14
EasyDry® product family
Easy to use, maintenance free: Inspection free Transportation/ assembly/
storage at any angle No humidity uptake during
storage
Excellent thermal and electrical properties Partial discharge free up to
double service voltage High thermal endurance
(class E, 120°C) Low dielectric losses (tan δ <
0.35 %)
The easy way of bushing
© ABB Group May 8/ 9, 2013 | Slide 15
EasyDry® bushings
Classification: dry, fine capacitive graded,
paper free, resin molded bushing
Minimum ambient temperature: - 40 °C
(- 60 °C on request)
Altitude of installation: ≤1000 m
(1800 m on request)
Pollution level: very heavy (31 mm/ kV)
Mounting angle: vertical down to horizontal
Standards IEC 60137 (2008)
IEEE C57.19.00 and C57.19.01
Common specifications
© ABB Group May 8/ 9, 2013 | Slide 16
Application: oil insulated transformers Type designation: DMB-OA Rated voltage: 24 – 170 kV BIL: 150 – 750 kV Rated current: 800 – 3,150 A Conductor types: cable bolt, removable or fixed solid rod Outdoor insulator: silicone rubber
EasyDry® bushings Application and range
© ABB Group May 8/ 9, 2013 | Slide 17
RIS Technology – EasyDry® bushings
You will get a dry bushing which provides maximum safety and reliability at the highest technical characteristics
Long-term storage is significantly easier and more economic
Transport, assembly and disassembly easier and simpler
Purchasing cycles are much shorter Optimised value for money Less capital bound for maintenance of
strategic reserve or intermediate stock Lowest impact on environment during
manufacturing, operation and disposal
Customer benefits summary
© ABB Group May 8/ 9, 2013 | Slide 18
Questions and discussion
© ABB Group May 20, 2013 | Slide 19