CN102286156A - Large-capacity dry-type transformer curing process - Google Patents

Abstract

The invention discloses a large-capacity dry-type transformer curing process, comprising a penetration stage of castable before being cured, a pre-curing stage under lower temperature and a post-curing stage under higher temperature. The large-capacity dry-type transformer curing process has the advantages that stepped segment curing is adopted, and stress concentration caused by overhigh temperature rising speed and fierce curing reaction is avoided, so that the internal stress of a coil winding is reduced to be lowest, and the cracking of the coil winding is avoided; after the pre-curing stage under the lower temperature, resin takes on an elastomer so as to be convenient for demoulding; and for the post-curing stage under higher temperature, the stepped curing also can be continuously adopted according to the condition of a workpiece so as to determine the stage number of steps and the temperature gradient.

Description

Large vol dry type transformer curing process

Technical field

The present invention relates to the transformer curing process, particularly a kind of large vol dry type transformer curing process.

Background technology

The dry type transformer capacity of common medium and small distribution poured with epoxy resin is 2500KVA and following, most manufacturers adopt the pressure pouring of band filler resin, the mould material that the poured with epoxy resin dry type transformer uses is bicomponent epoxy resin and solidifying agent, wherein bicomponent epoxy resin is that medium viscosity liquid bisphenol A Resins, epoxy, solidifying agent are methyl tetrahydrophthalic anhydride, during the cast of band filler, filler is silicon powder (silica powder).

To medium and small substation transformer, the cast of its coil and condition of cure, raw material production producer and transformer production manufacturer determine a general feasible cast and condition of cure according to reality usually.But cast and curing for the large vol dry type transformer more than the 4000KVA can not be suitable for, especially to the cast of band filler resin, be subjected to thermal distortion because of what transformer winding produced in operational process, resin ftractures easily, cast and curing process execution with medium and small substation transformer are infeasible, otherwise bring inconceivable consequence.

Summary of the invention

Goal of the invention: at the problems referred to above, the purpose of this invention is to provide a kind of large vol dry type transformer solidified technology that is applicable to, the required physical property of mould material when satisfying large vol coil actual motion.

Technical scheme: a kind of large vol dry type transformer curing process, this technology comprised with the next stage:

1) penetration stage of mould material before the curing, resin and solidifying agent carry out crosslinked, 6 hours time, 80 ℃ of temperature;

2) the preceding cure stage under the lesser temps, the mixing liquid of resin and solidifying agent transforms to solid state, and 7～9 hours time, temperature is between 90～110 ℃;

3) in the after fixing stage under the comparatively high temps, crosslinking curing further takes place in resin, and 8～10 hours time, temperature is between 110～130 ℃.

Because the stage 2) finish after, resin is elastomerics, is convenient to the demoulding, so the stage 2) can carry out stripping process after finishing.

Beneficial effect: compared with prior art, advantage of the present invention is to take the ladder segmentation to solidify, and avoids too fast because of heat-up rate, and curing reaction is fierce and cause stress concentration, thereby it is minimum that the internal stress of coil winding is dropped to, and avoids the coil winding cracking; After the preceding cure stage under the lesser temps, resin is elastomerics, is convenient to the demoulding; The after fixing stage under the comparatively high temps also can adopt ladder to solidify according to the workpiece situation continued, determines stagewise sum of series thermograde.

Embodiment

Below in conjunction with specific embodiment, further illustrate the present invention, should understand these embodiment only is used to the present invention is described and is not used in and limit the scope of the invention, after having read the present invention, those skilled in the art all fall within the application's claims institute restricted portion to the modification of the various equivalent form of values of the present invention.

A kind of large vol dry type transformer curing process, this technology comprised with the next stage:

1) penetration stage of mould material before the curing, resin and solidifying agent carry out crosslinked, 6 hours time, 80 ℃ of temperature;

2) the preceding cure stage under the lesser temps, the mixing liquid of resin and solidifying agent transforms to solid state, and 7～9 hours time, temperature is between 90～110 ℃;

3) in the after fixing stage under the comparatively high temps, crosslinking curing further takes place in resin, and 8～10 hours time, temperature is between 110～130 ℃.

Resin quiet putting in coil before solidifying, this stage resin and solidifying agent carry out crosslinked, make simultaneously resin in coil portion fully permeate; Preceding cure stage under the lesser temps, the mixing liquid of resin and solidifying agent transforms to solid state, this stage finish after resin be elastomerics, can be conveniently stripped, the demoulding again after also can curing process all finishing; The after fixing stage under the comparatively high temps, in order to make coil obtain best electric property, the curing in this stage also can continue to adopt ladder to solidify, and stagewise sum of series thermograde is determined according to the size of workpiece, avoid too fast because of heat-up rate, curing reaction is fierce and cause stress concentration.

Large vol dry type transformer curing process of the present invention after testing, reaches following technical parameter after implementing on the large vol dry type transformer:

Anti-heavy intensity 80～120MPa

Coefficient of elasticity 8000～10000MPa

Tensile strength 80～90MPa

Elongation at break 1～2%

90～95 ℃ of second-order transition temperatures

Thermal elongation coefficient 30～35(105/1c)

Thermal conductance 0.8～1.0(w/mk)

Surface resistivity 1014(Ω)

Specification volume specific resistance 1015(Ω)

Claims (2)

1. large vol dry type transformer curing process is characterized in that this technology comprised with the next stage:

1) penetration stage of mould material before the curing, resin and solidifying agent carry out crosslinked, 6 hours time, 80 ℃ of temperature;

2) the preceding cure stage under the lesser temps, the mixing liquid of resin and solidifying agent transforms to solid state, and 7～9 hours time, temperature is between 90～110 ℃;

3) in the after fixing stage under the comparatively high temps, crosslinking curing further takes place in resin, and 8～10 hours time, temperature is between 110～130 ℃.

2. large vol dry type transformer curing process according to claim 1 is characterized in that: can carry out stripping process after the stage 2) finishing.