SE439857B - DISTANCE TREASURER BETWEEN LEADER STORES FOR A STORAGE WINDOW FOR A TRANSFORMER OR REACTOR AND WAY TO MAKE SUCH A DISTANCE DISTRIBUTOR - Google Patents

Description

More particularly, the present invention relates to a spacer between conductor bearings for a bearing winding for a transformer or reactor cast with a filler-containing resin, characterized in that the spacer is built up of a flexible line of a blow-free polymer comprising parts arranged at a distance from each other to form channels between them, which extend to the end surfaces of the winding and which enable the filler-containing resin to penetrate into the winding.

It is essential that the rope is flexible for the winding to be compact.

It then lies, as is the case with the use of spacers of fiberglass material, namely everywhere against the underlying conductor layer without the formation of voids. A polymer rope also provides a safe distance between the conductor bearings with good dimensional tolerances. Because the polymer is homogeneous and void-free, it does not need to be impregnated with the resin. A particularly important feature of the present invention is that it enables a considerable simplification of the manufacture of a spacer of the type indicated. The distance holder can namely be manufactured from the flexible rope as such in connection with the manufacture of the winding. The line thus does not need to be pre-processed into a fabric or other product, where individual parts are held together into a unit, which can be applied in a purposeful manner. The rope is applied to the method according to the invention in the winding by being applied on top of a conductor layer while it is moved back and forth between the end surfaces of the winding while bending the rope at the end surfaces and while providing a distance between them in opposite directions. applied parts of the line to form channels between the parts, through which the filler-containing resin can penetrate into the winding.

Examples of useful polymer in the line include polyamide such as polyhexamethylene adipamide (Nylon 66), polycaproamide (Nylon 6) or a copolymer of polyhexamethylene adipamide and polyhexamethylene sebacamide, polyester such as polyethylene glycol terephthalate and further polycarbonate. The exemplified polymers are temperature resistant up to 155 OC, at least when embedded in a casting resin. They are also pressure-stable enough to permanently hold the conductors in adjacent bearings at the intended distance from each other.

The polymer line suitably has a diameter of 0.5-3.5 mm and preferably a diameter of 0.5-2.5 mm. Adjacent parts of the line within the same layer are arranged at a distance from each other laterally (width of the channels) of suitably 0.5-20 mm and of preferably 0.5-10 mm. hffïï '7:' f? “POGâ ä? The spacer according to the invention is preferably used in bearing windings with round or strip-shaped (rectangular cross-section) conductors of copper or aluminum. The conductor is preferably insulated with a lacquer which is temperature-resistant up to at least 155 OC, such as, for example, a lacquer of polyesterimide, terephthalic acid alkyd or polyurethane.

The casting resin intended for use with the spacer is a solvent-free resin containing a filler. The solvent-free resin may be, inter alia, an epoxy resin, an unsaturated ester resin or a polyurethane resin, especially those which are temperature resistant up to at least 155 ° C. Examples of suitable fillers, which are preferably of inorganic material, are powdered fillers such as quartz, alumina, mica flour, kaolin, lime and chalk and fibrous fillers such as short fibers (<5 mm) of glass or asbestos. The content of fillers suitably amounts to 20-50 percent, and preferably to 35-45 percent, of the volume of resin and filler together. Particularly preferred is an epoxy resin combined with a polyamide spacer because an epoxy resin wets very well and provides a very good bond to a polyamide. during casting, the winding is placed in a mold and the filler-containing resin is added. The resin then fills the space between the mold and the winding and penetrates between the conductor layers via the channels formed by the parts of the line in the spacer. The penetration of the resin into the channels can be facilitated by using a vacuum and heating the resin during casting.

Casting of coupling connections between winding parts and connecting means does not cause any problems.

The invention will be explained in more detail by describing exemplary embodiments with reference to the accompanying drawing, in which Fig. 1 shows a longitudinal section of a winding, Fig. 2 a part of a cross section (section AA in Fig. 1) through the winding and Fig. 3 schematically a side view of an embodiment of a winding during manufacture.

In the winding according to Figs. 1 and 2, which is a high voltage winding for a bearing-wound transformer, the spacer is designated 1 and the conductors 2. The conductors are axially wound close together in bearing 3. The spacer holds the conductor bearings at a designated distance from each other in the radial direction. Due to the construction of the spacers of parts of a line Ä which between them form channels 5 into which the resin can effectively penetrate, the channels are completely filled with filler-containing resin 6, which gels and hardens without emergence. of cavities. Since the polymer in the line is void-free, there are also no voids in the line, which means that the space between the conductor layers is filled in its entirety with a void-free insulation.

In the winding shown in Fig. 3 during manufacture, two detachable ends 8 are arranged outside the end surfaces of a body 7 for the winding, which are provided around the peripheries with evenly distributed hubs 9. The spacer is formed by a continuous line 4, which is applied substantially in the winding. axial direction in a reciprocating movement between the ends 8 with bending of the line around the hubs 9. The line is applied in a sparse structure during the formation of channels 5 between the parts of the line, eg the channel Sa between the parts Ha and Hb of the line and the channel 5b between the parts of the line Hb and Hc. To remove the ends 8 from the finished winding, the hubs 9 can be pressed in so that they do not protrude beyond the periphery of the ends or the rope is cut off in the places where it goes around the hubs.

Manufacture of a winding in accordance with the present invention may, for example, be available in the manner described below.

A tube with an inner diameter of 60 cm and a height of 80 cm and with a wall thickness of 3 mm is used as a winding frame 7. The tube is made of fiberglass-reinforced epoxy resin. At the ends of the pipe are screwed two ends 8 with the same outer diameter as the pipe. Each end is provided with slidable hubs 9 arranged around the periphery with a mutual distance of 5 mm. A lacquered copper wire 2 with a diameter of H mm is wound on the pipe. The wire is wound several turns in one layer. Then a rope H of void-free polyamide with a diameter of 1.0 mm is applied around these entire wire layers in a reciprocating motion with folding of the rope around the hubs at each end surface of the winding. Then a new layer of several turns is wound. of the lacquered copper wire on top of the layer of polyamide line. A new layer of polyamide line, similar to that described above, is applied on top of the layer of copper wire, after which additional layers of copper wire are wound on until the pre-wound coil consists of four layers of copper wire with sparsely applied polyamide line between each wire layer. The ends 8 are then removed, whereby the hubs are pressed in so that the ends are free from the line around the hubs. The coil is then placed in a mold consisting of a thin iron plate. The whole is placed in a vacuum oven and heated to 90 OC for ten hours. Then vacuum the oven, after which a hot degassed quartz flour filled ggroon QUALITY

Claims (3)

8505901-4 epoxy resin is poured on. The epoxy resin consists of 100 parts by weight of a bisphenol type resin (eg Araldit F from CIBA AG, Switzerland), 100 parts by weight of anhydride type hardener (eg HY 905 from CIBA AG), 1 part by weight of amine accelerator (eg DY 061 from CIBA AG) and 300 parts by weight (corresponding to U0 volume percent) of quartz flour. When the winding is completely covered by the resin, air is released to atmospheric pressure. The quartz flour-filled resin now penetrates into the channels 5 between the parts of the line and fills all the spaces between them. The line is then surrounded by the resin, which does not penetrate into the void-free polyamide. Then the temperature in the oven is raised to 120 OC, whereby the resin gels and hardens. Since the resin is everywhere filled with quartz powder, there are no unfilled resin portions, where cracks and blisters can occur and cause partial discharges due to electrical stress. Nor can partial discharges occur in the void-free polymer embedded in the resin. The winding is used as high voltage winding in a bearing wound transformer. PATENT REQUIREMENTS Spacer between conductor bearings (3) for a bearing winding cast with a filler-containing resin for a transformer or reactor, characterized in that the spacer (1) is built up of a flexible line (H) of parts of a void-free polymer ( Ha, Hb, Äc) which are arranged at a distance from each other to form channels (5, Sa, Sb) between them, which extend to the end surfaces of the winding and which enable the filler-containing resin to penetrate into the winding. 2. A spacer according to claim 1, characterized in that the polymer is a polyamide and the resin an epoxy resin. 3. A method of manufacturing a spacer between conductor bearings (3) for a bearing winding for a transformer or reactor to be cast into a filler-containing resin, characterized in that the spacer (1) is built up of a rope ( 4) of a void-free polymer by placing the rope on top of a conductor layer by passing it back and forth between the end surfaces of the winding while bending the rope at the end surfaces and providing a distance between adjacent parts in opposite directions (Ha, Hb ) of the line for forming channels (Sa) between the parts, which extend to the end surfaces of the winding and which enable the filling of the filler-containing resin in the winding.