The invention discloses a large oil-immersed
transformer insulated end ring and a
manufacturing technology thereof. The large oil-immersed
transformer insulated end ring comprises
casein glue
layers and a plurality of
layers of paperboards, and every two adjacent
layers of paperboards are glued via one of the
casein glue layer. The
manufacturing technology includes: A, utilizing a board shearing
machine to shear needed large electrical insulating paperboards into regulated dimension so as to obtain semi-finished paperboards; B, evenly spraying
distilled water on the surfaces of the semi-finished paperboards, guaranteeing the paperboards to have certain bending capability, utilizing a roller press to roll the paperboards into cylinders according to technical requirements; and C, selecting
casein glue which is strong in permeability on the insulated paperboards to glue the layers of the paperboards according to a single-face gluing technique, tightening the layers of the paperboards via a binding strap, placing in a
drying furnace to be subjected to
drying and vacuum oil spraying, and finally disassembling the binding strap. The large oil-immersed
transformer insulated end ring and the
manufacturing technology thereof have the advantages of simple technology, convenience in operation, reliability in performance, and capability of effectively avoiding or greatly reducing of transformer
partial discharge magnitude caused by closed air bubbles in insulating parts.