JPS5851715A - Partially eccentric structure type conduit aerial cable system - 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 a partially eccentric structure type aerial pipe cable system in which partially eccentric structure type pipe line aerial cable units are connected.

As shown in Figure 1, the conventional conduit aerial cable system employs a thick copper pipe or aluminum pipe as the conductor 1, "1", and this is mainly connected to a columnar insulating spacer 2 made of epoxy resin. Or conical cylindrical cone spacer 2'.
A conduit aerial cable unit that is coaxially supported and fixed within a pipe-shaped metal sheath 4.4" made of iron, aluminum, stainless steel, etc.) 1. Plug in the opposite ends of the conductor 1.1#, respectively.
A contact 5 is provided, thereby connecting the conductor 1. II and the connecting flanges 6.6' provided at the opposite ends of the metal sheath 4.4.

The spaces of the 1" and 4.4" metal sheaths were each filled with an insulating gas 3 such as 8F and gas (sulfur hexafluoride gas) having excellent insulation properties. In the conventional method described above, when the filling pressure of the insulating gas 3 is relatively low (
Approximately 1.0 to 15 Q/, gauge pressure), the withstand voltage of the space and the creeping withstand voltage of the insulating spacers 2..., 2#... are approximately the same - maintaining insulation properties. However, the withstand voltage characteristics of SF and gas 3 increase with the filling pressure of the gas, so when the filling pressure of SF and gas 3 to be enclosed is increased in order to improve the withstand voltage characteristics of the pipe line aerial cable, the insulating spacer 2.2' creeping voltage characteristics are compared to the voltage resistance characteristics of the space filled with SF6 gas 8 due to the disturbance of the electric field at the part where the spacer is connected to the conductor or sheath and the gas and metal insulators come into contact. However, in some cases, there is a relatively significant decrease in the withstand voltage characteristics.
The length of the creeping surface of the columnar insulating spacer 2 indicated by arrow A in the figure and FIG.
It is effective to make the distance relatively long compared to the distance (indicated by arrow B in Figures 1 and 2). In the case of the spacer 2', it is known that increasing the length of the conical cylindrical portion is effective. However, in the case of the columnar insulating spacer 2, since it is constructed as a single pillar, the pillar must be made thicker in order to obtain the required strength, and as a result, a thicker pillar is erected in a narrow space. Therefore, it is structurally difficult to increase the creepage length of the spacer, and the creepage distance between the conductor 1 and the metal sheath 4 becomes relatively short. In addition, in the case of a columnar spacer, since the direction of the electric field and the direction of the creeping surface of the columnar part of the columnar insulating spacer 2 are approximately the same, the electric field on the creeping surface is larger than that of the cone spacer.
Since the withstand voltage characteristics of SF6 gas 3 are controlled by the local maximum electric field, if discharge conditions are established in a very small area near the maximum electric field, such as near the conductor, the surface of the insulating spacer near the sheath, or the spacer mounting area, the This further progresses to areas where the electric field is weak, resulting in total circuit dielectric breakdown. On the other hand, in the conical cylindrical insulation type cone spacer 2, since the creeping direction and the direction of the electric field intersect, the electric field strength in the creeping direction is greatly reduced (about 178 to 1/4). Note that FIG. 2 is a sectional view taken along the line X-X in FIG. 1, and FIG. 8 is an end view taken along the Y-Y arrow direction in FIG. 1, and 2a and 2'a are spacer sleeves of the spacers 2 and 2g, respectively. .

This invention was made in view of the growth of the industry, and the conductor l supported and fixed by column-shaped insulating spacers 2 is arranged eccentrically with respect to the metal sheath 4, and the conductor l is arranged eccentrically with respect to the metal sheath 4. It is possible to connect to the conduit aerial cable unit ■ which has the conductor 1' supported and fixed coaxially with the metal sheath 4', and it also has an insulating gas filled (8F
Even when the filling pressure of the insulating gas 3 is increased, the withstand voltage characteristics of the insulating gas 3 and the withstand voltage characteristics (creeping insulation characteristics) of the columnar insulating spacer 2 maintain a balance, and the conical cylindrical insulating spacer ( The purpose of this invention is to provide a partially eccentric structure type conduit aerial cable system that can be smoothly connected to a coaxial conduit aerial cable unit (2) with a cone spacer).

The gist of the present invention lies in the structure of the partially eccentric structure type conduit aerial cable system described in the above claims.

Hereinafter, the present invention will be explained in detail with reference to the drawings showing the embodiments thereof. FIG. 4 is a longitudinal cross-sectional side view of the metal sheath of an embodiment of the basic configuration of the partially eccentric structure type conduit air cable tuft type according to the present invention. In the figure, a conduit aerial cable unit 1' is constructed such that a conductor 21 is arranged and fixedly supported at an eccentric position with respect to a metal sheath 24, and a conduit aerial cable unit 1' connected to this is configured so that a conductor 21 is arranged and fixed at an eccentric position with respect to a metal sheath 24.
' is constructed coaxially with respect to the metal sheath 24'.

In the above-mentioned conductor eccentric type conduit aerial cable unit 1', the conductor 21 is supported and fixed by the columnar insulating spacer 22, and the length of the pillar part is determined by the preset length of the conductor 21.
The conductor 21 is supported via the sleeve 22a of the columnar insulating spacer 22, and the conductor 22 is arranged, supported and fixed to the metal sheath 24 while maintaining the same eccentricity, and the coaxial type In the conduit aerial cable unit, the length of the conical part of the conical cylindrical insulating spacer 22' is set in advance in order to obtain characteristics that are higher than the withstand voltage characteristics of the columnar spacer with long legs on the eccentric unit side. The length of the conical insulating spacer 22' and the conductor 21' are made to coincide with each other, so that the conductor 21' is coaxially connected to the metal sheath 24'.
is supported and fixed by the insulating spacer 22' via the spacer rib 22'a. The conductors 21 and 21' of the eccentric structure type air conduit cable unit 1' and the coaxial type air conduit cable unit 1, which are configured as shown above, are For example, an eccentric block 25a is fixed to the connection end of the conductor 21 in the middle cable unit 1'.
The plug-in contact 25 is coaxially fixed to the metal sheath 24, and the plug-in contact 25 is connected to the pipe-shaped conductor 21' of the coaxial type air conduit cable unit ■'.
The connection is made by fitting the end of the In addition to using such an eccentric block, the same effect can be obtained by providing a plug-in contact with a similar function. Therefore, since the connection terminal of the completed eccentric structure type air conduit cable unit I# is always arranged in a coaxial position with respect to the metal sheath 24, compatibility of the air conduit cable unit 7) 1 is obtained. Further, the metal sheaths 24 and 24' have sheath connection flanges integrally formed at both ends thereof.
, 26 are not shown in the drawings, but are connected in an airtight manner with bolts and nuts. Pipeline aerial cable unit l'
By connecting . . . 1 [l . In addition, in the conduit aerial cable unit l, the cross-sectional shape of the conductor 21 is formed into an elliptical conductor 21b, as shown in the cross-sectional view of the columnar insulating spacer in FIG. 5(b), and the eccentric columnar spacer 22b is used to The long sleeve is the spacer 22b.
If the conductor 21b is arranged and supported so that it is perpendicular to the center line of the cross section of the long leg, the curvature of the conductor 21b in the direction of the electric field increases, so that the electric field strength that primarily affects the withstand voltage of the columnar insulating spacer 22b can be reduced locally. The columnar long leg type insulating spacer 22b can reduce the voltage and increase the withstand voltage, and the vertical conductor dimension can be shortened.
Together with increasing the effective creepage length of the spacer 22b, the withstand voltage characteristics of the spacer 22b can be improved.

Note that FIG. 5(a) is a sectional view taken along line A-A in FIG.
The figure is an end view of the B-B cross section in the direction of arrows in FIG. 4.

Since the present invention has a construction of the construction, the pillar portion of the columnar insulating spacer can be formed long, and its creepage distance becomes long. The electric field that directly affects the withstand voltage of the columnar insulating spacer can be locally relaxed, and together with the increase in the effective creepage distance of the long columnar insulating spacer, the withstand voltage characteristics of the columnar insulating spacer are improved. Further, since the length of the conical cylindrical portion of the conical cylindrical insulating spacer is also long, its creeping voltage withstand characteristics are improved, and it is possible to maintain a balance with the insulating characteristics of the long columnar insulating spacer. Furthermore, eccentric plug-in contacts are fixed to both ends of the conductor of the conduit aerial cable unit, which is supported and fixed on the long columnar insulating spacer, and the plug-in contacts are always arranged in a coaxial position with the metal sheath. Therefore, it is possible to easily connect to a conduit aerial cable unit of a different type to easily and quickly configure a partially eccentric structure type conduit aerial cable system.

It is also compatible with conventional pipeline aerial cables.

For example, in the conventional system for a 500KV system 80, the metal sheath inner diameter was 500 mm, the conductor outer diameter was 180 mm, the spacer sleeve had an outer diameter of 220 mm, and the insulation distance between the metal sheath inner surface and the conductor was 7 mm, but the conductor position was By eccentrically moving the insulating spacer upward in the direction of the pillar, the length of the pillar can be increased by about 20%. Together with this, the creeping voltage withstand characteristics of the insulating spacer of the air conduit cable are significantly improved. Further, in this method, the electric field inside the insulator can be lowered, and the insulation properties against penetration of the solid insulator can also be improved. Furthermore, in a conduit aerial cable unit having a conductor supported and fixed to a conical cylindrical insulating spacer and disposed coaxially with a metal sheath, which is connected to an eccentric structure type conduit aerial cable unit, Needless to say, since the length of the conical cylindrical portion is increased, the withstand voltage characteristics of the insulating spacer are also improved.

Since the present invention has the above-described structure and operation, according to the present invention, the length of the leg portion of the columnar insulating spacer is increased to support, fix, and arrange the conductor at an eccentric position with respect to the metal sheath. The conductors of the aerial cable unit and the conduit aerial cable unit in which the length of the conical cylindrical part of the conical cylindrical insulating spacer is lengthened and the conductor is coaxially supported, fixed, and arranged with the metal sheath I are Connections are made using eccentric plug-in contacts, and the space formed between each conductor and metal sheath is filled with a higher voltage insulating gas (for example, SF6 gas) than before, improving the withstand voltage characteristics of the insulating gas. In this case, it is possible to easily and simply improve the voltage withstand characteristics of each insulating surface of each conduit aerial cable unit in balance with the improvement of the voltage characteristics of the insulating gas, and to create a highly reliable conduit. An underground cable system can be obtained, and its effects are significant industrially and economically.

[Brief explanation of the drawing]

Fig. 1 is a centerline vertical sectional side view of a metal sheath of a conventional ductwork aerial cable system, Fig. 2 is a sectional view along the line X-X in Fig. 1, and Fig. 3 is an end view of the Y-Y sectional view in Fig. 1. , FIG. 4 is a longitudinal cross-sectional side view along the center line of the metal sheath of the partially eccentric structure type conduit aerial cable system according to the present invention, and FIG. 5 shows the insulation in the eccentric structure type conduit aerial cable unit adopted in the present invention. Figure (a) shows a cross-sectional view of the spacer, and Figure (a) is a cross-sectional view of A--A in Figure 4. Figure (b) is a cross-sectional view of the insulating spacer when the conductor cross section of the conduit aerial cable unit is elliptical. FIG. 6 shows an end view of the BB cross section in the direction of the arrow shown in FIG. 4. 21, 21b, 21'...Conductor, 22.2
2b, 22'...Insulation base? , 22a, 2
2',... Insulating spacer leaf, 23...
...Insulating gas (8F, gas), 24.24'...
...Metal sheath, 25...Plug-in contact, 25. ...... Eccentric block of plug-in contact, 26.26'... 7-range metal sheath connection, l... Eccentric structure type conduit aerial cable unit l I... ...Coaxial type air conduit cable unit.

Claims (1)

[Claims] (1) A conductor of a conduit aerial cable unit in which a pipe-shaped conductor is eccentrically supported and fixed inside a pipe-shaped metal sheath with a long column-shaped insulating spacer, and a pipe-shaped conductor with an oval male part-shaped insulating spacer. is connected to the conductor of a coaxial type air cable unit coaxially supported and fixed within a pipe-shaped metal sheath through an eccentric type plug-in contact or via an eccentric block. Partially eccentric structure conduit aerial cable system.