JPS5918581Y2 - butsing - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement in a particularly salt-resistant bushing used in high-pressure oil-filled equipment such as a transformer.

For transformer bushings located in areas subject to severe salt damage, it is generally not possible to use bushings with exposed conductive parts, such as bushings for pole-mounted transformers, and an external power distribution drawer edge is required in order to resist salt damage.

In this case, the salt may erode the area between the outer power distribution lead wire's coating and the core wire, or the coating may be eroded by the synergistic effect of the minute surface leakage current and the salt, causing salt from the outside air to enter the bushing. There is a problem in that the internal temperature of the transformer enters the transformer.

In order to solve these problems, bushings in salt-damaged areas are fitted with raised edges and the inside of the insulator is filled with synthetic resin, which cuts off the flow of air with the outside air due to capillary action, and completely embeds the conductive parts to prevent short-circuit accidents. It is designed to solve the problem.

Conventionally, in order to form the above structure, a leader wire connected in advance with a sleeve or the like was glued to the insulator tube, and the integrated insulator tube was filled and embedded with a thermosetting synthetic resin such as epoxy. Cracks occur in the synthetic resin due to the difference between the heat generated in the conductive part and the outside temperature during energization, and the difference between the internal temperature of the transformer and the temperature of the insulator tube itself exposed to the outside, and cracks occur in the insulator tube itself due to the difference in heat and cold. Ta.

In order to solve the above problems, the synthetic resin itself is flexible, and to prevent the occurrence of cracks in the porcelain tube, glass powder, quartz, etc. are mixed as filler materials, and the thermal expansion coefficients of the synthetic resin and the porcelain tube are unified. Efforts were made to prevent insulator pipes from cracking.

However, during heating and curing in the step after filling the synthetic resin, as shown in FIG. The resin outer peripheral part 3 is cured first, and the resin inner part 4 is gradually cured.
hardened into

In the case of the above conventional configuration, the diameter of the outer sheath 5a and the diameter of the core wire 5b of the lead wire 5 for internal use in high-voltage equipment are naturally different, and therefore, the synthetic resin 2 filled in the insulator tube 1 has protruding layers with different thicknesses. During heat curing, as mentioned above, the resin is cured sequentially from the outer periphery, so cracks are likely to occur in the resin in areas of different thickness.

Furthermore, cracks are also likely to occur at the ends of the external power distribution lead wires 6.

In addition, in the cold/heat test 1@ when the bushing is completed by the above process, the resin expands when it is hot, but in this case too, if there are parts with different thicknesses, the force applied to the insulator tube due to resin expansion becomes extremely large. However, this is a cause of cracking of the insulator tube during thermal testing.

Even during cooling, shrinkage, which is the opposite of the above, can cause cracks to occur.

These problems ultimately lead to transformer accidents, and the present invention attempts to eliminate the above-mentioned conventional drawbacks.An example of the invention is shown below with reference to FIGS. 2 and 3. I will explain.

Figure 2 is a half-sectional assembly diagram of the bushing according to the present invention;
The figure shows a protective cover made of high-strength fiber material according to the present invention, and the same numbers as above indicate the same parts.

The core wire 5b of the high-voltage equipment internal lead wire 5 and the core wire 6b of the external power distribution lead wire 6 are integrally connected by a sleeve 7, and are protected by a high-strength fiber material shown in FIG. 3 during the integral connection process. A cover 8 is provided at the position of the sleeve 7.

This protective cover 8 is made of, for example, glass fiber material, and a cylindrical object may be inserted from the end of the lead wire.
In this embodiment, a portion of the cross section is cut to make a zero-shape, and the cut portions 8a are overlapped so that they are not located at the same position.

In addition, the mold cone 9 of the insulator pipe 1 and the external power distribution lead wire 6
The parts are bonded together with an adhesive 10, and the inside of the insulator tube 1 is completely filled with synthetic resin 2 and hardened.

In FIG. 2, 11 is a case of the device, 12 is a support ring, 13 is a stopper, and 14 is a tightening screw.

As is clear from the above examples, according to the present invention, even if a protruding layer is formed, the high-strength fiber material is embedded inside it, and the fibers bind the synthetic resin, preventing cracks from occurring. The protruding layer is divided into two parts by the high-strength fiber material, which alleviates the force caused by expansion and contraction during cold and hot temperatures, and eliminates problems such as cracking of the porcelain pipe.

Note that the roughness of the high-strength fiber material is determined by the synthetic resin filled with it, and the higher the percentage of filler material is, the more the roughness is made to improve the passage of the filler, which increases the effect.

Further, the effect can be further improved by making the protective cover double or triple for cylindrical and C-cut products, but this should be determined as appropriate from the design and process considerations.

[Brief explanation of the drawing]

FIG. 1 is a half-sectional assembly view of a conventional bushing, FIG. 2 is a half-sectional assembly diagram of a bushing according to the present invention, and FIG. 3 is a perspective view of a protective cover used for the bushing.

Claims (1)

[Scope of utility model registration request] A lead wire for internal use of high-voltage equipment and a lead wire for external power distribution are connected in an insulator pipe with a sleeve, and the sleeve and the lead wire inside the resin are connected in a bushing made by filling a synthetic resin in the insulator pipe. A bushing that is partially covered with a protective cover made of high-strength fiber material and hardened into one piece.