Arent there any technological future for transformers

1
Arent there any technological future for
transformers?

• C. Sumereder
• Graz University of Technology
• Dep. High Voltage Engineering

2
Current and Future Technologies

• Substitution of cellulose NOMEX
• Substitution of mineral oil with
• Synthetic Liquids Esther, Silicone
• Biological Liquids Rape Seed Oil
• Solid/gas insulated transformer
• Cable Transformer
• Production VPI, VPE
• Superconducting transformers

3
Substitute of Paper

• Cellulose free Transformerboard from Aramidfaser
  NOMEX

4
Nomex

• Higher temperature durability, low thermal
  degradation
• Low contraction at drying
• Geometrical constance
• Good partial discharge behaviour
• Almost not flammable

5
Nomex

• Application for very high electrical anc
  thermical loads and low volumina e.g. traction
  transformers
• Maximum utilisation of machines
• Good overload behaviur without reduction of life
  time
• Disadvantage expensive, for this reason
  application in exposed parts of the insulating
  system

6
Insulating Liquids

• Minimum request Mineral oil
• Same electrical and thermic toughness
• more environmetally friendly
• Higher fire resistance
• Better efficiency

7
Insulating Liquids

• Synthetic
• Ester
• Silicone Oil
• Biologic
• Vegetable Oil Rape Seed Oil

8
Comparison of oil
9
Ester

• High combustion point
• low toxicity
• Good environmentally friendly
• Good thermodynamic properties
• Good dielectric properties
• Good partial discharge behaviour
• Mixable with mineral oil
• Ground water protected areas

10
Mixed Base Liquor
11
Rape Seed Oil

• Good dielectric properties
• Excellent environmentally friendly
• Ground water protected areas
• Disadvantage long time behaviour, drying and
  hermetic enclosure necessary

12
Environmental Impact
13
Dry Transformer

• 50 kVA bis 20 000 kVA
• 1 kV bis 36 kV
• Indoor
• Overload operation with fans
• Oilfree tap changer
• High fire resistance
• Environment friendly
• Recycelable

14
Construction
15
Cast Resin Winding
16
Fire Resistance

• DIN VDE 0532 Teil 6 (HD 464)

17
Cable Winding

• Use of an VPE-cable instead of a conventionell
  winding system
• Machines
• Powerformer
• 20-100 MW
• 30-150 kV
• Advantage windings can be build up to 400 kV
• Disadvantage no long time experience

• Transformers
• Dryformer
• 20-150 MVA
• bis 150 kV

18
Distribution Electrical Field
lt 3kV/mm gt 9kV/mm
19
Dryformer

• For power transformer no mineral oil is neccessary

20
Production Technology

• VPI (Vakuum Pressure Impregnation)
• From generator production
• Impregnation of the finished winding system with
  cast resin in a vacuum vessel
• Pore free absorption of cast resin
• Good impregnation

21
Production Technology

• VPE (Vakuum Pressure Encapsulated)
• Impregnation of the finished winding system with
  silicone in a vacuum vessel hydrophobe surface
• Soil proofing
• Applicatioin for ship transformers

22
Superconducting Transformer
23
Superconducting Transformer

• Warm or cold core
• OIL ? LN2
• Copper ? HTS

24
HTS Power Transformers

• With conventional technology up to 98
  efficiency ? HTS not economic
• Oil free power transformer
• Combination with current limiting function
• Reduction of short circiut currents

25
Advantages of HTS-Traction Transformers

• Very low losses
• Low weight
• Small dimentions
• Reduction of energyconsumption
• Lower CO2-emission
• Environmentally friendly

26
HTS Traction Transformer