Distribution transformer class 24 UE 548/2074 Series

cast resinvoltagemedium-voltage

SIRMET ELETTRICA constructs, repairs and modifies MV and LV epoxy resin transformers in the range from 160 KVA up to 10MVA and a maximum operating voltage of 36KV. The magnetic circuit is made with silicon lamination with low loss oriented crystals with 45 ° weaving in order to minimize the noise level. The core tightening system is sized to withstand the electrodynamic stresses of the windings in the event of a short circuit. The low voltage windings are normally made of aluminum or copper sheet insulated with F or H class materials. They are protected by H class, high cementation varnish, that once dried in the oven, forms a highly compact mass which is resistant to radial short-circuit stresses to obtain a reduced percentage of additional losses. The axial stresses are very low thanks to the single plate conductor. The MV coils are made of aluminum or copper wire or with a wire insulated with an interwoven polyester film. The coefficient of thermal expansion of aluminum, close to that of the resin, allows the structure to respond homogeneously to temperature variations due to frequent load changes, thus avoiding dangerous stresses that would damage the transformer over time. The different rolls of the medium-voltage winding are lined up and connected in series with each other so as to form a phase coil which is subsequently tested in order to check the insulation and the absence of partial discharges as per CEI 14- 8. The coil thus obtained is incorporated into an epoxy resin loaded and mixed with a computerized embedding system in an autoclave.