JPS58151809A - Finned columnar insulating spacer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in pleated tag-shaped insulating spacers for conduit aerial cables and the like.

Conventionally, when a conductive foreign substance gets mixed into the insulating gas filled inside a conduit aerial cable, etc., the foreign substance mixed in at the operating voltage of the cable, etc. jumps up inside the conduit aerial cable, etc. While repeating the movement, it accumulates in the vicinity of the columnar insulating spacer, which is mainly made of epoxy cast products, and is installed in pipes, aerial cables, etc., adheres to the creeping surface of the spacer, and reaches a conductor such as a pull with the above-mentioned ke, thereby forming a conductor. Since it is conceivable that a flashover may occur between the spacer and the sheath, a layer or a layer is integrally formed on the outer layer of the columnar part of the spacer so that the foreign matter mixed in and the elongation of the discharge stop midway along the creeping height of the columnar insulating spacer. Generally, multiple levels of pleats are formed. This type of pleat is provided as a countermeasure against conductive foreign matter mixed into the cable, etc., and its dielectric constant is higher than the dielectric constant of the insulating gas filled in the space between the conductor and sheath in the air conduit cable, etc. Since the pleats are large, the electric field near the columnar insulating spacer is disturbed and becomes unequal due to the formation of the pleats, which lowers the floodover voltage value of the spacer and lowers the withstand voltage characteristics of the insulating spacer.

To explain this with reference to a drawing of a conventional pleated insulating spacer for a conduit aerial cable, Fig. 1 is a longitudinal cross-sectional side view of the sheath of a conduit aerial cable equipped with a conventional pleated tag-shaped insulating spacer. , 2 is a pipe-shaped conductor, 2 is a pipe-shaped metal sheath, and 1 is a pleated tag-shaped insulating spacer mainly made of an epoxy resin cast product that supports and fixes the conductor 1 within the metal sheath 2. A pleat 3'' is integrally formed on the outer periphery of the leg 3'.

The outer diameter a of the upper leg and the outer diameter a' of the lower leg of this pleat 3''
are formed to have the same dimensions. The distribution state of the equipotential lines under the working voltage in such a pleated tag-shaped insulating spacer is as shown by the dashed-dotted line in the figure, and as it approaches the sheath 2 side, the distance between them becomes wider, and an unequal electric field is formed. . In other words, the presence of the pleats 3 on the legs 3' of the pleated insulating spacer causes the electric field to be disturbed and the spacer to be disposed in an uneven electric field, and the electric field is concentrated at points F and G in the figure. do. As a result, there is a drawback that the withstand voltage characteristics of the pleated insulating spacer are reduced.

This invention alleviates the tendency for the electric field to concentrate on the pleated tag-shaped insulating spacer in an upwardly tilted state and that the dielectric breakdown voltage of the spacer depends on the maximum electric field due to the electric field concentration in an uneven electric field. The object of the present invention is to provide a pleated tag-shaped insulating spacer for pipes, aerial cables, etc., which can prevent a decrease in the temperature.

The gist of the invention lies in the structure of the pleated tag-shaped insulating spacer described in the slanted claims.

Hereinafter, the present invention will be explained in detail with reference to the drawings showing embodiments thereof. FIG. 2 is a longitudinal side view of the conductor supported by the pleated insulating spacer according to the present invention, in which the same parts as in FIG. 1 are designated by the same reference numerals;
This figure shows a pleated bill-shaped insulating spacer, and a one-step extension 8'' is integrally formed on the outer periphery of the pedestal portion 31 of each spacer. Column bottom outer diameter C
The dimensional relationship between b and c is formed such that b>c. FIG. 8 shows another embodiment of the pleated tag-shaped insulating spacer according to the present invention, in which the same parts as in FIG. 2 are denoted by the same reference numerals. Pillar part 8'
Two levels of pleats a# and S# are integrally formed on the outer periphery of the pillar portion, respectively. In this case, the outer diameter of the pedestal of the upper tier 8'' is bl, and the outer diameter of the pedestal between the upper tier 8'' and the lower tier 3'' is cl, and the outer diameter of the pedestal of the lower tier 3'' is defined as bl. Assuming the diameter is C, the dimensional relationship between these outer diameters is bl>c
+>e. Furthermore, when the number of stages of pleats is large, it is preferable that the outer diameter of the pillar is reduced in the two directions of the sheath as shown in FIG. Furthermore, the pillar whose diameter is reduced in two directions of the sheath can be used even when the number of folds is small.

In this invention, the shape of the pleated tag-shaped insulating spacer in a conduit aerial cable, etc. is configured to be diagonally upward, so that when the conductor is supported by the pleated tag-shaped insulating spacer and installed in the sheath, it is possible to The equipotential lines in the pipe are the second
As shown by the dashed-dotted line in the figure, the distance between them becomes wider as it approaches the sheath 2 side, but since the diameter of the lower pillar is gradually reduced across the folds, the equipotential line is pushed down to the bottom of the leg. The equipotential line density (equipotential line spacing) of the entire column group is made uniform. In other words, by reducing the diameter of the pedestal from the conductor side to the sheath side, the difference in permittivity of the pedestal is used to increase the electric field distribution, approaching an equivalent electric field. It is.

Since the present invention has a diagonal configuration and operation, according to the present invention, the electric field distribution in the pleated tag-shaped insulating spacer in a conduit aerial cable etc. can be made close to an equal electric field distribution, and equivalently, the The electric potential gradient of the spacer can be relaxed and the withstand voltage characteristics of the spacer can be improved, which is advantageous in terms of economics and improvement of the electrical characteristics of pipes, aerial cables, etc. Although this invention has been mainly described with respect to a pleated columnar spacer for an air conduit cable, it can also be applied to a pleated tag-like insulating spacer for a gas insulated bus bar, and the range of application is wide.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a longitudinal cross-sectional side view of a sheath for explaining a conventional pleated tag-shaped insulating spacer for a conduit aerial cable, and Figs. FIG. 2 is an explanatory side view of a swingable pleated bill-like insulating spacer. 2... Sheath, D... Folded tag-shaped insulating spacer 3'
...Folded tag-shaped insulating spacer leg, 3", 3"...
Pleat % bl clb, cle ... Pleated property insulating spacer leg diameter.

Claims (2)

[Claims] (1) In a one-stage or multi-stage pleated tag-shaped insulating spacer for a conduit aerial cable, etc., the outer diameter of the lower column of each pleat is formed smaller than the outer diameter of the upper column of the pleat. A pleated tag-shaped insulating spacer. (2) A single-stage or multi-stage pleated tag-shaped insulating spacer for use in conduit aerial cables, etc., characterized in that the pillars on which the pleats are formed are formed with a reduced diameter so as to taper toward the sheath side. A pleated tag-shaped insulating spacer.