GEAFOL Neo — Cast-Resin Distribution and Static Converter Transformers

The GEAFOL Neo: a true GEAFOL and more

The GEAFOL Neo is the further development of the proven GEAFOL Basic, building on more than 55 years of GEAFOL cast-resin technology while adding innovations aimed at special applications. Distribution and static converter transformers up to a maximum rated power of 6,3 MVA are almost ten percent lighter than comparable models from the proven GEAFOL series, and the slimmer construction also shrinks the overall dimensions.

Because distribution transformers frequently operate in the direct vicinity of people, the family is built to the highest safety requirements: all units meet VDE 0532-76-11 / IEC 60076-11 / DIN EN 60076-11 (GOST, SABS or CSA/ANSI/IEEE available on request) and are always tested by UL/CSA/TUV. They satisfy Climatic Class C3, Environmental Class E3 and Fire Classification F1, making them safe for residential and work environments.

Placing the transformer close to the consumer in a load-center arrangement reduces network complexity and transmission losses, but space near the consumer is usually scarce. The GEAFOL Neo's combination of performance, safety and small dimensions — together with a high degree of standardization — delivers a strong cost-benefit ratio and lets the transformer be installed in almost any environment, with no need for coolant collecting troughs.

Further development of proven technology and Ecodesign compliance

With well over 150,000 GEAFOL transformers in service worldwide, the essential building blocks — the aluminum strip winding and foil winding — were adopted unchanged to preserve reliability and long service life. The mechanical construction and the high-voltage windings, however, were redesigned to be lighter and smaller, which considerably improves heat dissipation. Fewer horizontal surfaces mean less dust deposition, further reducing the already minimal maintenance effort and increasing operational reliability. The design is also prepared for end-of-life: all metal parts as well as the cast resin can be recycled in an environmentally friendly way.

Since July 1, 2015, transformers installed within the European Economic Area must meet the ecodesign requirements implementing Directive 2009/125/EC, with the CE mark as evidence of compliance. GEAFOL Neo transformers are designed accordingly — particularly low-loss and economical — and fulfill DIN EN 50588-1.

The GEAFOL Neo can already be configured to stage two (Tier 2) of the Ecodesign Directive, which sets stricter minimum energy-efficiency standards mandatory from July 1, 2021; such units meet EN 50708-2-1 and EN 50708-3-1.

Built-in safety and reliable design

The high-voltage coils are manufactured from aluminum foil (copper on request). In a foil winding only the simple turn-to-turn voltage appears between layers — versus double the layer voltage in a conventional round-wire winding — giving great power-frequency and impulse voltage strength. The epoxy-resin vacuum casting of the HV windings is performed at high temperature, avoiding hazardous entrapped gas and keeping the winding free of partial discharges up to twice the rated voltage, reflected in an excellent MTBF index.

The low-voltage strip winding is also aluminum (copper on request), with the strip width practically equal to the coil length to sharply reduce axial short-circuit forces. Conductive and insulating materials are bonded by heat treatment into a compact unit that also handles radial forces reliably; the winding ends are encapsulated in resin.

Extensive trials combining Siemens GEAFOL transformers with vacuum switches have shown the GEAFOL medium-voltage windings handle switching overvoltages from interrupting magnetization currents without difficulty and without needing overvoltage protection.

Feature overview

Headline features and advantages of the GEAFOL Neo family:

Construction and features

The transformer is built from eight principal elements: (1) a three-limb core of grain-oriented, low-loss electric sheet steel insulated on both sides; (2) a low-voltage winding of aluminum (alternatively copper) strip with turns permanently bonded with insulating Prepreg sheet; (3) a high-voltage winding of individual aluminum (alternatively copper) foil-technology vacuum-cast coils; (4) lifting eyes integrated in the upper core frame; (5) delta connection tubes with HV terminals; (6) a clamping frame and truck with convertible rollers for longitudinal and transverse travel; (7) epoxy-resin/quartz-powder insulation that makes the transformer extensively maintenance-free, moisture-proof, tropics-suitable, fire-resistant and self-extinguishing; and (8) high-voltage tappings of +/- 2 x 2.5% on the HV terminal side, reconnectable in de-energized condition.

Temperature monitoring uses PTC thermistor detectors in the low-voltage windings (Pt100 sensors on request). Steel parts get a two-component coating in RAL 7016, with a special two-component coating available for particularly aggressive environments. The structure is made of individual components, so windings can be individually assembled and replaced on site.

Ordering data — Ecodesign Tier 2 (as of July 1, 2021)

Selection of ordering data for GEAFOL Neo transformers per Ecodesign Directive 2009/125/EC, EU Regulation No. 2019/1783, Tier 2. Rated secondary voltage 0,4 kV (no-load); HV tapping +/- 2 x 2.5%. Columns: rated power Sr [kVA], rated primary voltage Ur HV [kV], insulation level HV (AC/LI) [kV], impedance voltage uzr [%], no-load losses P0 [W], load losses Pk120 [W], noise level LWA [dB], order number, total weight [kg], length/width/height [mm]. All units comply with DIN VDE 0532-76-11/DIN EN 60076-11/IEC 60076-11/DIN EN 50708-2-1 and 50708-3-1; power ratings > 3150 kVA, different voltages and designs as well as special equipment on request. Dimensions are approximate.

Selected rows (10 kV and 20 kV standard designs; the catalog also lists 50/125 and 70/145 insulation-level variants for 630 kVA and above):

Ordering data — Ecodesign Tier 1 (as of July 1, 2015)

The parallel table for Tier 1 designs (per Ecodesign 2009/125/EG, EU Regulation No. 2019/1783, complying with DIN VDE 0532-76-11/DIN EN 60076-11/IEC 60076-11/DIN EN 50588-1) uses the same order numbers as Tier 2 but with higher losses and generally lower weights. Selected rows (10 kV and 20 kV standard designs):

Ordering data — GEAFOL Neo standard series (non-Ecodesign)

A third ordering table covers the standard GEAFOL Neo series (100–2500 kVA, order numbers 4GX...-3CY/-3GY/-3DY/-3HY), complying with DIN VDE 0532-76-11/DIN EN 60076. For each rating it offers multiple loss/noise variants at 10 kV (28/75) and 20 kV (50/95), impedance 4% or 6%. Examples: 100 kVA 4GX5044-3CY (P0 440 W, Pk120 1850 W, LWA 61 dB, 600 kg, 1190 x 685 x 920 mm) down to low-noise 4GX5044-3HY variants; 1000 kVA spans 4GX6044-3CY (2100 W / 10000 W / 73 dB / 2560 kg) to 4GX6064-3HY (1800 W / 9000 W / 65 dB / 2760 kg); the largest listed is 2500 kVA 4GX6464-3HY (3500 W / 19000 W / 71 dB / 5070 kg, 1990 x 1280 x 2135 mm). Power ratings > 2500 kVA, different voltages and designs as well as special equipment on request.

Truck dimensions

A dimension drawing defines overall dimensions A1, B1 and H1 (tabulated per type on the ordering pages) plus roller dimensions; dimension e applies to both longitudinal and transverse travel. Callouts: 1 = high-voltage terminal, 2 = high-voltage tappings at the HV terminal side, 3 = low-voltage terminal.

Terminal dimensions (low-voltage)

Hole measurements for 400 V low-voltage terminals use four drilling patterns (Fig. 1–4), all with 14 mm diameter holes; the applicable pattern and spacings a/b depend on rated power.

Accessories: fan cooling and temperature monitoring

GEAFOL Neo transformers can be equipped with fans to raise the power rating by up to about 50% (depending on type). With a 30% power increase, for example, the listed short-circuit losses rise by about 69% and the short-circuit voltage increases linearly by 30%. Fans are switched automatically via temperature sensors in the LV winding together with a fan controller.

Winding temperature is monitored in the low-voltage winding by PTC thermistor detectors or, on request, Pt100 sensors; in static converter transformers the core temperature is also monitored. Every GEAFOL transformer carries at least one PTC thermistor detector loop for tripping — the most cost-effective monitoring solution. With two PTC sensor systems, one gives an alarm and the other switches the transformer off, their nominal operating temperatures differing by 20 K; a third system can control the fans. When a sensor's response temperature is reached its resistance rises sharply and the trip relay switches immediately; once the winding cools about 6 K below the operating temperature the relay resets. The trip relay's ambient limit is 55 degrees Celsius, so it suits installation in medium- or low-voltage distribution cabinets. Accessories are supplied on request.

Sensformer, housings and housing order data

Sensformer — gateway to digitization: an IoT device that collects and transmits transformer data to secure storage and analytics. Default measurements are low-voltage winding temperature, low-voltage winding current and GPS location. Features include secure GSM or Ethernet transmission with cyber-security measures, cloud data storage with a graphical analysis UI, and software applications for further value creation.

Innovative housing design: the award-winning GEAFOL housing shares the new transformer family's styling. Transformer and housing are delivered on a common base frame as a permanently mounted unit for high mechanical stability; the roof opens from inside for crane hoisting, connection bolts sit inside the housing for personnel safety, and the fully modular construction allows later upgrade to a higher IP class. Indoor and outdoor versions exist in multiple protection classes, with options such as an infrared window or air/water heat exchanger.

Standard housings ship as construction kits in five protection variants selected by the 14th character of the order number: IP00 (A, no housing, indoor), IP20 (B, indoor), IP23 (C, indoor), IP23D (D, indoor) and IP23DW (E, outdoor). Higher classes progressively add protection against accidental contact, foreign matter > 12,5 mm, water spray up to 60 degrees from vertical, access with wire (test wire 1 mm per EN 60529), and — for the outdoor IP23DW version — snow and direct sunlight; salty air and aggressive chemical atmospheres are handled across all variants, with a special paint finish for outdoor installation. A labyrinth arrangement of ventilation louvers guards against wire access; a power reduction is possible when the transformer is installed inside the protective housing. Housings come in five sizes — e.g. outdoor IP23DW size 1: 1440 x 1070 x 1540 mm, 153 kg up to size 5: 2380 x 1540 x 2950 mm, 392 kg; indoor IP20 size 1: 1390 x 1010 x 1335 mm, 121 kg up to size 5: 2360 x 1500 x 2340 mm, 290 kg. Housing-to-transformer assignment tables map every transformer type to its housing size — from size 2 for the smallest 100 kVA units up to size 5 for the largest units (2000–2500 kVA in the standard series; in the Ecodesign table 2000 kVA takes size 4 and 2500 kVA size 5, with > 2500 kVA housing upon request); for IP20 add 100 mm height, for IP20/IP23/IP23F variants add 100 mm width and height per the footnotes. Frame-construction housings with doors and roof ventilators, and versions for combined installation with LV and MV cabinets, are also available.

Figures & drawings

Click any figure to enlarge.