A Medium Voltage Cast Transformer with Combined Insulation

Abstract

The invention discloses a combined and insulated intermediate-pressure cast instrument transformer, which comprises a primary winding, a secondary winding and an insulating layer. The combined and insulated intermediate-pressure cast instrument transformer is characterized in that the primary and secondary windings are wrapped with a semiconductor crepe paper shielding layer, wherein the insulating layer on a master insulating part between the primary and secondary windings is a polyurethane insulating layer obtained by vacuum drying treatment, vacuum injection at normal temperature and vacuum stirring degassing; a non-master insulating part positioned on the outer side of the primary winding is provided with an inorganic insulating material filler. According to the combined and insulated intermediate-pressure cast instrument transformer, the electrical performance of the intermediate-pressure cast instrument transformer is remarkably improved, local discharge is reduced, the product is prevented from aging and even breakdown and burst, the running reliability of the product is improved, and the combined and insulated intermediate-pressure cast instrument transformer is strong in mechanical strength, low in cost, safe and environmentally-friendly.

Description

technical field [0001] The invention relates to a transformer, in particular to a combined insulation medium-voltage casting transformer. Background technique [0002] The existing 10~40.5kV medium-voltage transformers used in power systems are generally cast with high-temperature epoxy resin. Epoxy cast transformers, Picture 1-1 It is a structural schematic diagram of an epoxy-cast medium-voltage cast-type current transformer in the prior art. Figure 1-2 It is a structural schematic diagram of an epoxy-cast medium-voltage castable voltage transformer in the prior art. Figure 1-3 It is a schematic side view of an epoxy-cast medium-voltage castable voltage transformer in the prior art. There must be enough gaps between the primary winding 11 and the secondary winding 12 to form an insulating layer 13, and vacuum casting or APG methods are used to fill the gap with epoxy resin, and the insulating layer formed by epoxy resin bears a The voltage between the secondary condu...

AI Technical Summary

Problems solved by technology

[0003] This kind of epoxy resin for casting is equipped with a relatively large proportion of fillers because it has to bear the corresponding mechanical strength. This kind of filler will make the castable more viscous, affect the effect of vacuum degassing, and cause partial discharge.

Epoxy resin will generate stress during high temperature curing, and its toughness is very poor, and it is prone to cracking and bursting during use

Images