The safe technology of GEAFOL / CARECO cast-resin transformers
Wherever distribution transformers have to assure the utmost safety in areas frequented by people, GEAFOL / CARECO® cast-resin transformers are the ideal solution. With GEAFOL / CARECO, the limitations of liquid-filled transformers are avoided, but the proven characteristics such as operating safety and service life are retained. GEAFOL / CARECO cast-resin transformers comply with IEC 60076-11 or EN 60076-11 as well as VDE 0532-76-11. However, they can also be designed to meet special national regulations or customer wishes. We offer tailored solutions that meet all requirements when it comes to operating mode, low noise and loss levels, connection technology, type of cooling, as well as transport and installation.
Safety proven 100,000 times over There are good reasons why GEAFOL / CARECO cast-resin transformers are used wherever absolute safety is required. They can be found in high-rise buildings, hospitals, road and underground railway shafts, offshore installations, mines, wind turbines, nuclear power plants, and many other similar safety-critical environments. It is not surprising that the superior GEAFOL / CARECO technology is produced under license by many transformer manufacturers all over the world. Over 100,000 GEAFOL / CARECO cast-resin transformers have proven themselves in power distribution all round the globe. The diagram below shows the power rating and voltage range developments achieved since 1966 as a result of continuous innovation.
GEAFOL / CARECO transformers, with their environmentally sustainable technology and versatility, ensure efficient energy distribution at load centers. GEAFOL / CARECO transformers cover an output range from 100 kVA to approx. 20 MVA with operating voltages up to 35 kV.
The perfect technology of GEAFOL / CARECO cast-resin transformers
Maintenance-free – environmentally friendly – rugged: The insulation:
GEAFOL / CARECO transformers are insulated with an epoxy resin/quartz powder mixture. This is an environmentally friendly material that makes the windings maintenancefree, moisture-resistant, tropicalized, flame-retardant and self-extinguishing. This eliminates the need for additional flame-retardant chemicals, such as aluminum oxide trihydrate, which can negatively affect mechanical properties as well as aging. Even when the insulation is exposed to arcing, no toxic gases are generated. The windings are clamped between resilient spacers that provide effective vibration insulation both from the iron core and mutually between windings. The result: GEAFOL / CARECO transformers are as quiet as oil-immersed types.
Electrically safe: The aluminum/copper foil winding :
The coils of the high-voltage windings are made of aluminum/copper foil. Why foil windings? Because foil windings combine a simple winding technique with a high degree of electrical safety. The insulation is subjected to less electrical stress than in other types of windings. In a conventional round-wire winding, the interturn voltages can add up to twice the interlayer voltage, while in a foil winding it never exceeds the plain voltage per turn because each layer consists of only one winding turn. The result: High power frequency and impulse voltage withstand capability. Why aluminum is recommanded? The thermal expansion coefficients of aluminum and the used cast resin are so similar that thermal stresses due to load changes are kept to a minimum.
No gas inclusions: The epoxy resin casting process :
The high voltage windings are potted with epoxy resin under vacuum at a high temperature. This procedure prevents undesirable gas inclusions. The quality of the potting combined with the electrical advantages of the foil winding plays a decisive role in providing freedom from partial discharges (up to twice the rated voltage). The low-voltage strip winding is also of aluminum/copper. The width of the aluminum/copper strip is equal to the length of the coil. This considerably reduces axial shortcircuit forces in the transformer. The conductor strip and the insulation material are bonded together by heating and thus form a compact unit with sufficient strength to withstand radial forces reliably, for example in the case of short circuits.
Universal: The application areas :
Dry-type transformers must be marked with proven environmental, climate and fire resistance ratings. Our GEAFOL / CARECO cast-resin transformers are suitable for universal use and satisfy the requirements of the highest defined classes, as proven in comprehensive testing: • Environmental class E2 • Climate category C2* • Fire resistance class F1
* For outdoor installation, IP 23 degree of protection must be maintained.
Voltage stress
The flexible technology of GEAFOL / CARECO cast-resin transformers
50 % performance reserves – with radial-flow fans
Radial-flow fans with temperature-dependent control can be installed to provide capacity reserves and to cover peak load periods. In this way, the transformer output can be raised by up to 50 %. To simplify installation and connection, the transformer is optionally available with connection on either the HV or LV side, top or bottom (note: LV connections are usually located on top, if fans are installed). Plug connections are also available
Uncomplicated: Planning with maximum freedom
Planning with GEAFOL / CARECO does away with the limitations imposed by conventional transformer technology. Since these transformers can be installed without difficulty at load centers, optimum supply system concepts are possible. No special safety features are required (such as coolant-collecting troughs). Since the GEAFOL / CARECO transformers often need less space than liquid-filled and gas-insulated transformers, a higher output can be accommodated in the same area. The modular design of the transformer is another economical feature. Windings, for instance, can be mounted and replaced on the spot.
CO2 balance
State-of-the-art transformers reduce the CO2 balance because of their high efficiency and low transport losses. Thanks to environmentally friendly product design and the resulting reduction in materials and final weight, CO2 is reduced during the manufacturing process as well.
Economical: No maintenance, no maintenance costs
GEAFOL / CARECO transformers are practically maintenance-free. Once connected, in most cases they can be left to get on with their job. If the advantages of GEAFOL / CARECO transformers are taken into consideration as early as at the planning stage, the overall costs of a power supply system can often be considerably reduced.
Disposal
GEAFOL / CARECO transformers are long-lasting investment goods with an economic lifetime of 30 or more years. Yet despite that, the time will come when the product will need to be replaced and disposed of. GEAFOL / CARECO cast-resin transformers have a high recycling rate. On average, only 4 % of the material is used thermally, 2 % of the material can be disposed of in the landfill, and a full 94 % of the material can reenter the raw material cycle and be reused. It is conceivable that this material will be used again in your facility as a new transformer.
Radial-flow fans increase performance by up to 50 %
GEAFOL / CARECO standard protective casings, e.g. to IP 20 degree of protection; optionally, modified housing designs are possible
630 kVA GEAFOL / CARECO cast-resin transformer, Ur = 20 kV
Selection of ordering data for Standard 10kV/11kV
A. Electrical data
B. Mechnical data
Selection of ordering data for Standard 20kV/22kV/24kV
A. Electrical data
B. Mechnical data
Selection of ordering data for Standard 33kV/35kV
A. Electrical data
B. Mechnical data
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