Resin Power Transformers
GBE SpA manufactures resin transformers up to a power of 30 MVA and voltage of 52 kV, with Off Circuit or On Load Tap Changer. The constructive design of a power transformer is completely different from that of a distribution transformer. The masses involved are quite big, and at the design stage it is necessary to take into account not just the mechanical and electrical stresses but also the issues related to the materials expansion during operation. A correct distribution of the electric field within the windings must be ensured to avoid partial discharges issues or problems related to the overvoltage resonance and this is guaranteed by GBE design that considers the proper distribution of the capacities between coils, layers and parts of the coils, and to the ground. For the power transformers, the constructive design takes into account any dimensional aspects of the transformer based on the type of installation and especially the optimization of losses so to guarantee a competitive product not just considering the purchase price, but also the operation cost.
Oil Power Transformers
GBE supplies oil power transformers up to 50 MVA with voltage of 145kV (BIL650), with Off Circuit or On Load Tap Changer. TheOn Load Tap Changer can be either external or internal to the transformer tank. The oil power transformer is made according to constructive and design criteria as to ensures the highest operational reliability and a great performance in the electrodynamic stress, as well as excellent isolation so to avoid problems related to possible network overvoltages. The magnetic core is made with high permeability 45 degrees cut steel sheets in the European or American step lap type. The pack tighteners of the magnetic sheets are sized appropriately to ensure the mechanical sealing, noise reduction, and any problem relating to the handling or stresses of the windings. The MV and HV windings are made of a disc or with transposed cable conductors; they are made with horizontal or vertical winding machines by experienced staff in a controlled environment. The positioning of the coils and the gap between them and between the layers is performed according to the precise indications of the electrical design, as well as the type of conductor and the its processing. The drying and pressing process of the windings prior to assembly is fundamental and is carried out in a furnace with dry air circulation, monitored and recorded temperatures.
The power transformer can have two or more windings and can be fitted with compensation winding.
