JPS6320085B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a connecting portion of an OF cable, and more particularly to a connecting portion having a structure that allows the length of the connecting portion to be shortened.

In an OF cable line, a manhole is generally provided at the connection point of the cable, and an offset is provided inside the manhole to absorb the amount of thermal expansion and contraction of the cable. The magnitude of this offset, that is, the length and width, is determined by the voltage class of the cable, the size of the conductor, changes in the amount of load used, the distance between rows and the degree of inclination to the adjacent manhole, the cable installation condition, etc. , Once the length and width are determined, the size of the manhole is determined.
However, since manholes are generally underground structures and are very expensive, it is desirable to construct them as small as possible. Therefore, it is necessary to configure the length of the connecting portion of the cable to be as short as possible.

On the other hand, when introducing a cable into an existing manhole, for example when replacing it with a cable of a larger voltage class or size depending on the amount of electricity used, the size of the manhole is constant, so the cable connection can be shortened. It is necessary to configure it in this way.

As mentioned above, due to factors such as the difficulty of constructing new large manholes in urban areas, the frequency of cable replacement according to power demand, and the ultra-high voltage class, there is a significant need to make cable connections as short as possible. It's getting expensive.

In view of the above-mentioned circumstances, the present invention aims to shorten the connection portion without impairing electrical quality compared to conventional ones.

First, the connection part of a conventional OF cable will be explained based on FIG. In the same figure, 1, 1 is a conductor,
2 is a connection sleeve, 3, 3 is a cable insulation paper layer,
Reference numeral 4 denotes a hand-wound reinforcing insulating paper layer, and tapered boundary surfaces 5, 5 are formed by abutment between each end surface of the cable insulating paper layers 3, 3 and both end surfaces of the reinforcing insulating paper layer 4. The insulating paper layer is discontinuous at these boundary surfaces 5, 5, and the electrical strength (dielectric strength or allowable electrical stress strength) is small, so the inclination angle of the boundary surfaces 5, 5 is larger than the limit depending on the cable. It cannot be made at an angle (steep slope). On the other hand, if the shielding layer 7 on the metal sheath 6 side is directly connected to the outer ends of the boundary surfaces 5, 5, the shielding layer 7 on the metal sheath side will be shielded from the ground potential from the high voltage conductors 1, 1. Since the layer 7 is connected in a straight line, the electric breakdown strength is further reduced. Therefore, an additional reinforcing insulating paper layer 8 is usually formed over a range beyond the outer ends of the boundary surfaces 5, 5.

Both ends of the additional reinforcing insulating paper layer 8, that is, the portions beyond the upper ends of the boundary surfaces 5, 5 are one reason why the connection portion is lengthened. The present invention attempts to shorten the overall length of the connection portion compared to the conventional one by shortening the above-mentioned portion without impairing the electrical quality.

FIG. 2 shows a first embodiment of the invention.
The conductors 1, 1, the connection sleeve 2, and the cable insulating paper layers 3, 3 in the figure are the same as those described above, but they are different in the structure of the boundary surfaces 5, 5 and the additional reinforcing insulating paper layer 8. .

That is, each boundary surface 5 formed by butting the end surface of the cable insulating paper layer 3 and the end surface of the hand-wound reinforcing insulating paper layer 4 has a first tapered surface 5a of the inner layer and a second tapered surface 5b of the outer layer. The first tapered surface 5a
is formed between the outer peripheral surface of the conductor 1 and the middle of the boundary surface 5, and has a slope that gradually moves away from the conductor 1 as it approaches the metal race 6. 1st above
A bending point 9 that bends toward the center of the connection part is formed at the outer end of the tapered surface 5a, and a second tapered surface 5b is formed between the bending point 9 and the outer peripheral surface of the cable insulating paper layer 3. There is. Its tapered surface 5b
is tapered inversely to the first tapered surface 5a.
Therefore, the length of the virtual line l extending from the bending point 9 to the outer peripheral surface of the insulating layer at the slope of the first tapered surface 5a,
The lengths of the second tapered surfaces 5b are formed to be approximately equal. In other words, the second tapered surface 5
When the termination point 14 formed by the reinforcing insulating layer 4 forming b on the outer circumferential surface of the cable insulating layer 3 extends from the bending point 9 to the outer circumferential surface of the cable insulating layer 3 at the slope of the first tapered surface 5a, the reinforcing insulating layer 4 4 is located inside the connection part from the virtual taper termination point 15 formed on the outer peripheral surface of the cable insulation layer 3.

An additional winding reinforcing insulating paper layer 8 is formed on the outer circumferential surface of the hand-wound reinforcing insulating paper layer 4, and both ends thereof extend from the outer end of the second tapered surface 5b to the cable insulating paper layer 3.
It is formed by extending the required length to the outer circumferential surface of. Both ends may be long enough to extend beyond the bending point 9, as shown by the dashed line in FIG.

In the conventional case, since the boundary surface 5 extended almost linearly in the direction of the sheath 6 without bending, both ends of the additional reinforcing insulating paper layer 8 were made to sufficiently cover the outer ends of the boundary surface 5. , as shown by the two-dot chain line in FIG. The outer end of the second tapered surface 5b is located closer to the center of the connection part, and the reinforcing insulating layer 8 is shortened by that amount. As a result, the length of the entire connecting portion can also be shortened. Further, since the distance from the outer end to the inner end of the boundary surface 5 is almost the same as that of the conventional one, the electrical quality is maintained at the same level.

FIG. 3 shows the second embodiment, in which case the first
A cylindrical surface 5c is formed between the tapered surface 5a and the second tapered surface 5b, and the directions of the slopes of both the tapered surfaces 5a and 5b are made to match, and the length of the cylindrical surface 5c is shorter than in the conventional case. Accordingly, the outer end of the second tapered surface 5b can be formed closer to the center, and the connecting portion can be shortened similarly to the first embodiment.

FIG. 4 shows a third embodiment, in which the first tapered surface 5
A cylindrical surface 5c is formed between the second tapered surface 5b and the second tapered surface 5b, and the direction of inclination of the second tapered surface 5b is opposite to that of the first tapered surface 5a.

FIG. 5 shows a fourth embodiment, in which an intermediate tapered surface 5d inclined in the same direction as the first tapered surface 5a and an intermediate tapered surface 5d are provided between the cylindrical surface 5c and the second tapered surface 5b in the third embodiment. A cylindrical surface 5e is formed. In this way, the tapered surfaces 5a, 5 are formed in multiple stages.
By forming e and 5b, the additional reinforcing insulating paper layer 8 can be further shortened.

Next, a method for assembling the above-mentioned connecting portion will be explained with reference to the first embodiment (see FIG. 2).

First, as shown in FIG. 6, the OF cables A and B to be connected are overlapped slightly and cut at the center as shown by the chain line. This cutting point becomes the conductor connection point, that is, the center point of the connection part. Next, cables A and B
The metal sheath 6 at the connection side end is peeled off to a required length, and as shown in FIG.
The curl groups formed by the unwinding are unwound longer as they are closer to the outer surface, and are properly fixed.
The portion where the insulating paper layer 3 is rewound is the range shown by the chain line in FIG. 7, and its thickness determines the thickness of the second tapered surface 5b described above. After unwinding to a required thickness, the remaining portion of the insulating paper layer 3 is peeled off in steps to form a tapered surface 11.

Next, as shown in FIG. 8, the conductors 1, 1 of the cables A and B to be connected are connected by the connecting sleeve 2, and the outer periphery of the conductor connection part and the end surfaces of the insulating paper layers 3, 3 of both cables are connected. Divide a wide insulating paper between 11 appropriately, wrap it by hand so that the dividing lines do not overlap, and wrap both end surfaces of the insulating paper layers 3, 3 into end surfaces 11.
The first tapered surface 5a is formed by abutting against the first tapered surface 5a. In order to closely abut the tapered surfaces, a separately prepared narrow roll of insulating paper may be wrapped and filled between 4 and 11. Furthermore, both end surfaces of the hand-wound reinforcing insulating paper layer 4 are bent from the outer end of the first tapered surface 5a toward the center of the connection part to form a bending point 9, and from the bending point 9, a reversely tapered end surface is further formed. .
As a result, approximately V-shaped recesses 12, 12 are formed between the end face of the reinforcing insulating paper layer 4 and the metal sheath 6. Therefore, the rewound tape 10
is rewound again and wound in order to fill the recesses 12, 12. When the tape 10 hits the end face of the reinforcing insulating layer 4 by rewinding, the tape 10 is cut and removed at that point. Thus, the unwound insulating paper layer 13,
13 is formed (see Figure 2). The abutting surface between the inner circumferential surfaces of the unwound insulating paper layers 13 and the end surface of the reinforcing insulating paper layer 4 forms the aforementioned second tapered surface 5b.

After forming the unwound insulating paper layers 13, 13 in this manner, an additional insulating paper layer 8 is formed around the outer periphery of the unwound insulating paper layers 13, thereby forming the connection portion of the embodiment shown in FIG.

In the case of the second embodiment shown in FIG. 3, after forming the unwound insulating paper layers 13, 13, the remaining half of the outer layer side of the hand-wound reinforcing insulating paper layer 4 is formed.
The other embodiments are also assembled in the same manner as the above-mentioned embodiments, so the explanation thereof will be omitted.

As described above, the present invention forms the interface between the cable insulating layer and the reinforcing insulating layer at the connecting portion of the OF cable by at least two tapered surfaces, and the outer end of the first tapered surface is directed toward the center of the connecting portion. The cable is bent, and a second tapered surface is formed between the bending point and the outer peripheral surface of the cable insulation layer.
The additional insulating layer is shorter than the conventional one, which has the effect of shortening the overall length of the connection part. In addition, the distance from the bending point to the outer circumferential surface of the cable insulation layer including the second tapered surface is equal to or greater than the conventional distance of the tapered surface, that is, the virtual distance when extending from the bending point at the slope of the first tapered surface. It is preferable to form it larger because the electrical quality is further improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the conventional example, Fig. 2 is a sectional view of the first embodiment, Fig. 3 is a sectional view of the second embodiment, Fig. 4 is a sectional view of the third embodiment, and Fig. 5 is a sectional view of the third embodiment. A sectional view of the fourth embodiment, FIG. 6 is an explanatory view of an assembly preparation process, and FIGS. 7 and 8 are sectional views during assembly. 1... Conductor, 3... Cable insulation paper layer, 4...
Manual winding reinforcing insulating paper layer, 5... Boundary surface, 5a... First tapered surface, 5b... Second tapered surface, 8... Additional winding reinforcing insulating paper layer, 9... Bending point, 13... Unwinding Insulating paper layer, 14, 15...terminal point.

Claims (1)

[Claims] 1. A reinforcing insulating layer is formed between the outer periphery of the conductor connection portion and the end faces of the cable insulating layers of both cables to be connected, and the end faces of the cable insulating layer and the end faces of the reinforcing insulating layers are abutted. Therefore, in the connection part of the OF cable that forms a tapered boundary surface, the boundary surface is formed by at least two tapered surfaces, and the first tapered surface is formed so as to be inclined from the outer circumferential surface of the conductor toward the cable sheath. The outer end of the first tapered surface is bent toward the center of the connection part, and a second tapered surface is formed between the bending point and the outer circumferential surface of the cable insulating layer, and the reinforcing insulating layer When the termination point formed on the surface extends from the bending point to the outer peripheral surface of the cable insulation layer at the slope of the first tapered surface, the reinforcing insulation layer is located inside the connection part than the tapered termination point created on the outer peripheral surface of the cable insulation layer. characterized by
OF cable connection. 2. The OF cable connection portion according to claim 1, wherein a cylindrical boundary surface is formed between the bending point and the second tapered surface. 3. The distance from the bending point to the outer peripheral surface of the cable insulation layer, including the second tapered surface, is equal to or greater than the distance extending from the bending point to the outer peripheral surface of the insulation layer at the slope of the first tapered surface. A connecting portion of an OF cable according to claim 1 or 2, characterized in that the OF cable connecting portion is formed.