State-of-the-art distribution transformers


CG Power Systems cast resin transformers: when safety and performance are paramount
CG Power Systems cast resin transformers are ideally suited for environments that demand the highest level of safety. Used widely in diverse settings – from office and apartment buildings, to hospitals, underground transport systems, and industrial and off-shore installations – the CG Power Systems cast resin transformers have a proven track record for safety and high-performance.
Certified safe
Suitable for power ratings from 100 kVA up to 10 MVA with operating voltages up to 36 kV, the full product range meets CENELEC EN 60076-11 and IEC 60076-11 regulations.
These safety certifications guarantee that the transformers:
> self-extinguish and emit a minimum of fumes in the event of fire (F1);
> are reliable under conditions of high thermal shock (C2);
> perform well in damp, dusty, salty and polluted environments (E2).
State-of-the-art construction for optimum performance
The magnetic core of the transformer is made of cold-rolled grain-oriented silicon sheets insulated on both sides by a thin coating of inorganic material. Hot-dipped galvanized steel plates are used for yoke compression, while the step-lap technique of cutting and mounting, and the final paint finishing completes the manufacturing process. The careful choice of flux density values, combined with the highest-quality materials and state-of-the-art production methods, guarantee that the magnetic core produces minimum vibrations and noise levels, low losses and low no-load currents.
Safety features of low voltage windings
Aluminum foil is used in the low voltage windings to ensure that the electric current and temperature are evenly distributed along the height of the windings, thus eliminating hot spots. The Class F layer insulation is interleaved with the conductor to create a solid cylinder, and each winding is pre-impregnated and cured in an oven providing optimum solidity and maximum protection against moisture and environmental pollution.
Safety features of high voltage windings
CG Power Systems high voltage windings are made of aluminum, the preferred material in the manufacture of high voltage windings; aluminum has similar expansion coefficient to resin, thus eliminating the risk of fissures or micro-cracks in the coils. During the deep-vacuum casting process, dosing and mixing is automated to guarantee consistent quality; and after casting, windings are cured in an oven according to an automated time-
temperature program. Casts have been successfully submitted to severe climatic tests (class C2), representing the most extreme conditions under which coils would operate.
Optimal thermal protection
CG Power Systems cast resin transformers are protected against thermal overload by two PTC resistors fitted in each of the low voltage windings at the hottest spot. The respective resistors are connected in series of three to a two-contact relay that controls the alarm and tripping functions.
Environmentally friendly
The CG Power Systems casting system uses the most environmentally friendly materials and processes available. Both cold and warm pollution are eliminated, as the system uses no liquids that could result in leakage, or halogens, toxic or corrosive gases that would create pollution during a fire. The epoxy resin is of Class F thermal stability and contains the environmentally harmless fine quartz powder and alumina trihydrate. The product is manufactured in accordance with the temperature limits set by the IEC 60076-11 standards. Furthermore, the nature of the material used in production makes the windings maintenance-free, moisture resistant, flame retardant and self-extinguishing.
Easy installation and connection
As the CG Power Systems cast resin transformers do not require specific fire-safety arrangements, they can be installed near the load, thus reducing installation costs. Additionally, the transformer can be connected on top of the HV and LV side as standard, further facilitating ease of installation. On special request, bottom connection on HV side is also available, as are plug-in connectors. As additional protection a standard range of enclosures with protection degree of IP20, IP21, IP23 or IP31 can be provided.
Reliability a priority
As one of the leading manufacturers of transformers in Europe, CG Power Systems has the necessary in-house expertise to manufacture consistently high-quality products. All cast resin transformers comprehensive performance and safety tests in accordance with the IEC 60076-11 standard.
These include:
> ratio and vector group check;
> winding resistance measurement;
> impedance voltage measurement;
> no load loss and no load current measurement;
> insulation testing with applied and induced voltage;
> load loss measurement;
> partial discharge measurement.

Special tests are also available upon request.