Dry transformer GEAFOL

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Overview
Wherever distribution transformers have to assure the utmost safety in areas frequented by people, GEAFOL® cast-resin transformers are the ideal solution. With GEAFOL, the limitations of liquid-filled transformers are avoided, but the proven electrical, mechanical and especially thermal characteristics are retained.

Quality standards
GEAFOL transformers from Siemens Energy exceed highest safety standards and comply with relevant laws and regulations. Key conformity and quality aspects include:

• Conformance with IEC 60076-11 / VDE 0532-76-11 / DIN EN 60076-11
• Compliance with Ecodesign Directive and monitoring of regulatory changes (EU, US DOE and others)
• Capability to meet national standards (GOST, SABS, CSA/ANSI/IEEE) on request

Fire, environmental and climate classes (IEC 60076-11)

• E3 Environmental class (higher classes on request)
• F1 Fire behaviour class (highest defined class)
• C3 Climate category (higher classes on request)

Technology and insulation
The GEAFOL principle produces transformers with excellent electrical, mechanical and thermal characteristics while being environment-friendly. Key technology features:

• Coils and windings are insulated with an epoxy resin and quartz powder mixture (eco-friendly)
• Insulation properties: almost maintenance-free, moisture-resistant, tropicalized, flame-retardant, self-extinguishing
• No toxic gases produced, even under arcing
• Special coil support spacers isolate vibrations from the iron core to ensure very low noise levels

Windings and casting

• High-voltage windings: aluminum foil
• Advantages of foil windings: simple winding techniques, high electrical safety, less electrical stress on insulation, high power-frequency and impulse voltage withstand capability
• Aluminum chosen for thermal-expansion compatibility with cast resin, minimizing thermal stresses
• Alternative copper windings available on request (named CARECO)
• High-voltage windings potted with epoxy resin under vacuum at high temperature to prevent gas inclusions and ensure freedom from partial discharges
• Low-voltage strip windings also made of aluminum; conductor strip and insulation bonded by heating to form a compact, strong unit able to withstand radial forces

Sustainability
GEAFOL dry-type transformers are insulated with epoxy resin/quartz mixture instead of oil — an environmentally friendly alternative. GEAFOL dry-type transformers are completely recyclable.

Digitalization
GEAFOL transformers are produced as Sensformers by default, equipped with sensors that transmit operational status data to secure storage and analytics tools so operators can optimize operations based on customized data analytics.

Product variants and characteristics

• GEAFOL Neo: Innovative clean design, low weight and small dimensions, suitable for use in almost every environment; Rated power up to 6.3 MVA; Highest voltage for equipment Um up to 40.5 kV; Application areas include modern functional buildings, residential and work environments, wind power plants.
• GEAFOL: Maximum power-to-volume ratio, highly efficient cooling, handles peak loads up to five times the rating; Rated power up to 50 MVA; Highest voltage for equipment Um up to 52 kV; Application areas include buildings, offshore platforms and ships, mining conveyors and refineries, rolling mills.
• GEAFOL converter transformers: High short-circuit withstand capability, great heat capacity, high overload capability; Rated power up to 50 MVA; Highest voltage for equipment Um up to 52 kV; Application areas include off-shore installations, oil rigs, conveyance facilities, DC-powered light rail systems, steel mills.

Accessories and options
Available accessories and tailored solutions include:

• Temperature monitoring: PTC thermistor sensors, PT100 resistance temperature detectors, capillary tube thermometers
• Radial-flow fans with temperature-dependent control to provide capacity reserves and cover peak load periods (can raise transformer output up to ~50%)
• Standard and modified housings for environmental protection and safety
• Connection options: HV/LV side, top or bottom, plug connections available

Typical application areas
GEAFOL dry-type transformers are used in indoor or environmentally sensitive areas such as hospitals, schools, commercial buildings, data centers, offshore platforms, industrial plants, wind turbine nacelles and other locations where fire safety, low maintenance and environmental protection are key.

Additional notes
GEAFOL transformers have proven performance under extreme conditions including ambient temperatures up to ±60 °C, aggressive salt-laden atmospheres and high mechanical stress (e.g., ships, cranes, wind turbine nacelles).

Technical specifications

• Denomination: GEAFOL® cast-resin dry-type distribution transformers
• Insulation material: epoxy resin + quartz powder mixture (eco-friendly, recyclable)
• Fire class: F1 (highest defined class)
• Environmental class: E3 (higher classes on request)
• Climate category: C3 (higher classes on request)
• High-voltage windings: aluminum foil (alternative copper CARECO on request)
• Casting process: epoxy potting under vacuum to prevent gas inclusions and ensure freedom from partial discharges
• GEAFOL Neo rated power: up to 6.3 MVA; Um up to 40.5 kV
• GEAFOL rated power: up to 50 MVA; Um up to 52 kV
• GEAFOL converter transformers rated power: up to 50 MVA; Um up to 52 kV
• Cooling: natural air (AN) or forced air (AF) with optional fans for increased capacity
• Sensors / digitalization: Sensformers (operational sensors and analytics capability)
• Standards: IEC 60076-11 / VDE 0532-76-11 / DIN EN 60076-11; other standards (GOST, SABS, CSA/ANSI/IEEE) on request