JPS6056045B2 - insulation spacer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a thermosetting resin cast product having embedded fittings, which is disposed in a conduit such as a conduit aerial power transmission line or a gas insulated switchgear, and which supports and insulates a conductor. The present invention relates to an insulating spacer that improves the bond between the embedded metal fitting of a cast product and the cast resin.

There is a risk of mechanical stress or thermal shock between the embedded metal fitting and the casting resin after casting due to the stress caused by curing and shrinkage of the casting resin and the difference in thermal expansion coefficient between the embedded metal fitting and the resin. , heat cycling causes mechanical damage to the joint surfaces. This damage is a particularly serious problem when the implant is large, has a complex shape, and is exposed to harsh conditions. As an example of such an electric component that is a cast product, an insulating spacer S for a conduit aerial power transmission line shown in FIG. 1 supports and insulates a conductor 2 in a conduit 1 filled with insulating gas. When an abnormal current that can reach tens of thousands of amperes flows, it must withstand the electromagnetic force acting on the conductor and the abnormal rise in gas pressure within the pipe. In addition, the insulating spacer must be able to withstand temperature increases due to energization and heat cycles due to changes in climate over a long period of time under normal energized conditions. Conventionally, this type of insulating spacer has an insulating part 3 with a high voltage side electrode 4, as shown in FIG.
Metal fittings such as the ground side electrode 6 are embedded.

In particular, the high-voltage side electrode 4 is an H-shaped one as shown in Fig. 2, taking into consideration the functions of 1) controlling the electric field, 2) gas tightness and adhesive strength of the resin interface, and 3) maintaining the dimensional accuracy of the cast product. has been used. The shape of the electrode that satisfies these functions is often an undesirable shape from the perspective of controlling the stress remaining in the cast product, and special technology is required to manufacture it to compensate for this. did. Proceeding from the general type insulating spacer described above, in order to further control the electric field and maintain dimensional accuracy, we separated the electric field control function and the airtight adhesion function of the electrode, and created an electrode with a simple shape. An improved insulating spacer as shown in FIG. 3 can be considered.

To manufacture a spacer using this improved method, the joint strength and airtightness of the joint must be stronger than that of the general method insulating spacer shown in Figure 1, and its performance must be sufficiently guaranteed against heat cycles. . As described above, an object of the present invention is to improve the withstand voltage characteristics, mechanical strength, and The purpose is to improve airtightness. Another object of the present invention is to improve the bond between the electrode and the resin to the extent that the improved insulating spacer described above can be put to practical use, and to facilitate the formation of a shield for electric field control. .

Therefore, the present invention provides an insulating spacer having an embedding fitting molded with a thermosetting resin, in which a porous metal sintered layer sintered with the embedding fitting is poured onto at least a portion of the surface of the embedding fitting. There is an insulating spacer characterized in that the porous metal sintered layer is provided at a thickness of 6 to 50% of the total thickness of the mold resin, and is cast after sufficiently impregnating and hardening the resin into the porous metal sintered layer. In the insulating spacer obtained by the present invention, firstly, between the embedded metal fitting and the casting resin,
An intermediate layer is provided, which is a porous sintered metal layer impregnated with a casting resin, which intermediate layer has properties intermediate between those of metal and resin, in particular a coefficient of thermal expansion.

Second, the boundary between the intermediate layer and the embedded metal is mechanically (the intermediate layer is also sintered with the embedded metal) and chemically (the resin that has sufficiently impregnated the intermediate layer is connected to the embedded metal). The boundary between the intermediate layer and the resin is chemically bonded (the resin is attached with an extremely wide bonding area), and the embedded metal fittings and the casting resin are bonded together. It can be said that the bond between the two is extremely strong. And insulation! In the spacer, voltage resistance characteristics, mechanical characteristics, and airtightness can be guaranteed, and a spacer that is highly reliable over a long period of time even when subjected to heat cycles can be obtained. FIG. 4 is a sectional view of a high voltage side electrode with an intermediate layer used as a spacer of the improved method.

A high voltage side electrode 41 made of material or gunmetal is placed in a mold, and a 150 to 2
Gunmetal powder with a particle size of 0.00μ is mixed, compacted, and heated in a hydrogen atmosphere.
By holding at 00 to 900°C for 20 to 3 minutes,
It was possible to form an intermediate layer with a porosity of 25%, which was also sintered with the high voltage side electrode. The metals forming the intermediate layer include copper-tin, lead-bronze, iron-copper, aluminum-copper, etc.
Any material that can be sintered with the electrode to form a porous sintered metal may be used, and by using metal fibers, the porosity etc. can be freely selected. All or part of the material to be sintered may be sprayed, plated, vapor-deposited,
It can be applied to the electrode by sputtering and sintered to form the intermediate layer.

The resin is impregnated into the intermediate layer, and the difference in thermal expansion coefficient between the intermediate layer and the resin layer is small.

Therefore, even if the porous sintered metal layer has a fairly complex external shape, phenomena such as peeling will not occur at the interface between the intermediate layer and the resin portion. The intermediate layer, which is a porous sintered metal layer sufficiently impregnated with casting resin, is provided to have a thickness of 6 to 50% of the total thickness of the casting resin (the total thickness of the intermediate layer and the resin portion). If this thickness is less than 6%, the effect of the intermediate layer will be insufficient, and if it exceeds 50%, the insulation properties of the resin will deteriorate, which is not preferable.
The absolute value of this intermediate layer is at least 8wn thick given the typical insulating spacer geometry. This means that
As shown in FIG. 5A, the sintered metal layer of the intermediate layer 53 can be ideally configured as a shield part for electric field control, and both mechanical and electrical characteristics can be maintained at a high level. Similarly, Fig. 5B shows a post-shaped insulating spacer, and if a buried electrode structure is used to improve mechanical strength (especially bending strength), the electrical properties (dielectric strength) will decrease, and this can be improved. For this purpose, a shield for electric field control is provided as an intermediate layer. FIG. 6 is a sectional view showing how the post-shaped insulating spacer of FIG. 5B is used. The post-shaped insulating spacer P supports and insulates the conductor 2 in the insulating gas-filled conduit 1, as shown in the figure. In order to sufficiently impregnate the porous intermediate layer with a casting resin such as an epoxy resin, vacuum impregnation is preferably performed.

The impregnation is preferably carried out at a relatively high temperature of the casting resin. Curing of the casting resin must be carried out in a program that results in minimal residual stress.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional general type insulating spacer, and FIGS. 2A and 2B are a sectional view and a plan view, respectively, of a buried electrode on the high voltage side used in FIG. 1. FIG. 3 is a sectional view showing an improved type of insulating spacer.
FIG. 4 is a sectional view showing the structure of a high voltage side electrode provided with a porous metal sintered layer used in the present invention. FIG. 5A is a sectional view of a high voltage side electrode provided with a porous metal sintered layer that also serves as a shield for electric field control. 4 and 5A are cross-sectional views of electrodes used in the improved method, and FIG. 5B is a cross-sectional view of a post-shaped insulating spacer. FIG. 6 is a sectional view showing how the insulating spacer of FIG. 5B is used. 1... Grounding case, 2... Conductor, 3... Insulating spacer insulation part, 4... High voltage side electrode, 5...
... Metal flange, 6 ... Ground side electrode, 3
2... Electric field control shield, 42...
Porous metal sintered layer (intermediate layer), 53...Intermediate layer that also serves as a shield, 51...Embedded electrode.

Claims (1)

[Claims] 1 In an insulating spacer having an embedded metal fitting casted with a thermosetting resin, a porous metal sintered layer sintered with the embedded metal fitting is provided with a thickness of at least 8 mm, and the porous metal sintered layer is coated with resin. An insulating spacer characterized by being sufficiently impregnated and cured and cast.