220kV Transformer

Specifications

The Coil

The high-voltage(HV) coil adopts an interleaved-continuous structure to improve the voltage characteristics under impact voltage and make voltage evenly distributed. All stays and chamfered to keep highly reliable insulation.

In the transformer winding there is a zigzag oil guide structure so as to fully cool all areas inside the winding, lower the temperature rise of the winding and the hot points of the winding and prolong the service life of insulation. The HV and MV regulation system are independently provided with voltage-regulating winding to balance the ampere turn of each winding, effectively lower the axial electrodynamic force generated at short-circuit of transformer and improve abrupt short-circuit withstanding capacity.

The winding adopts radial"0" margin design, between the core and the paper sleeve of LV winding, and between the LV, HV, voltage-regulating windings, as well as before insertion of stays and shroud plate they are fully dried and tightly matched to ensure extremely good compactness and concentricity of the entire winding.

The Core

The core is made of high-permeable grain-orientated top quality cold-rolled silicon sheet and the material is cut with advanced Germany Geoge GmbH automatic shear line with the cut burrs controlled within 0.02mm.

The silicon sheet fabrication adopts "no-upper yoke-lapped" technology and all lapped joints of the silicon sheet are 45 full-miters. The laminated core sheets are integrally pressed and adhered with epoxy resin to make the three-leg two-yoke core a strong and flat integral one with good verticality precision, this effectively improves no-load performance and reduces noise.

Bracing plates are used as support between coil leg and inner coil. The iron yoke is tied with epoxy resin-impregnated glass fiber band, and the lower iron yoke and the lower section of oil tank is tightened with counter-pressure bolts. The upper iron yoke and the upper iron yoke and the upper section of oil tank are fixed at 3 locations. Hence the body inside the oil tank can withstand the vibration during transportation without any shirt.

Main technical Parameters for thre-phase two winding on-load-tap-changing power transformer

Main technical Parameters for thre-phase two winding non-excitation-tap-changing power transformer