JPS6248446B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an insulating coated conductor, and particularly to a conductor whose coated length is reduced.

Conventionally, insulated busbars and other insulated conductors that are drawn into switchboards to downsize them are supported by a grounding system such as a bracket attached to a wall or bulkhead through an insulated support member such as a supporting insulator. However, when connecting a bare conductor such as a branch bus bar to this insulated conductor, a part of the covering must be peeled off, so the part supported by the insulated support member and the bare conductor must be peeled off. There are problems such as the need to increase the length of the insulated conductor between the part to which it is connected.

The present invention has been made in view of the above-mentioned problems, and its purpose is to reduce the length between the support part of the insulating support member and the connection part of the bare conductor, thereby reducing the size of switchboards, etc. An object of the present invention is to provide an insulated coated conductor that can be used for various purposes. Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

The insulated conductor 1 according to the present invention is drawn into and arranged in a switchboard (not shown) in order to downsize it, and as shown in FIG. It is constructed by covering the outer periphery of the conductor 2. Further, the insulated conductor 1 has a part of its covering 2a peeled off in order to connect a bare conductor (not shown) such as a branch bus bar, and is connected to a grounding board such as a bracket fixed to a wall or bulkhead of a switchboard or the like. It is insulated and supported by a fixed system 3 via an insulating support member 4 such as a support insulator made of porcelain or resin. Flange-shaped first pleats 5 and second pleats 6 are integrally provided near the end (left end in the figure) of the covering 2a of the insulated conductor 1 and on the outer periphery near the insulating support member 4. At the same time, this first pleat 5 and second pleat 6
A flange-shaped third fold 7 is integrally provided on the outer periphery of the covering 2a near the middle part (1/2l) of the distance 1 between the cover 2a and the cover 2a.

Each of the pleats 5, 6, and 7 functions to prevent the progression of flashover during flashover, and is made of the same material as the covering and has approximately the same outer diameter and shape. , the first pleats 5 and the second pleats 6 are formed at the ends of the covering and the insulating support member 4 in consideration of manufacturing convenience and the like.
and within 10% of the distance between the two. In addition, the wall thickness of the covering 2a, each of the pleats 5, 6, and 7, and the outer diameter of each of the folds 5, 6, and 7 are determined by the general formula for the flash voltage of creeping breakdown in the back electrode system, as described later. It is determined by the distance between poles (creepage distance) between the end of the object 2a and the insulating support member 4, the capacitance of the dielectric material forming the covering 2a, etc.

Here, in a bottomed cylindrical case 8 having a length of about 700 m/m and made of epoxy resin with one end closed,
One electrode 9 with an outer diameter of 30 m/m corresponding to the conductor 2
is inserted as shown in FIGS. 2 and 3, and the other ring-shaped support insulator 4 (grounding fixing system 3) is inserted on the outer periphery of the bottom side (left side in FIG. 2) of the case 8. The electrode 10 is fitted, and an outer diameter of 90 mm is attached to the outer periphery of the bottom side and the opening side of the case 8.
m/m ring disc-shaped first and second folds 11,
12 and the second electrode 10 and the open end of the case 8 are each 100 m/m, and the first,
The length between the second folds 11 and 12 is 500m/m
At the same time, the first and second folds 1
Using a simulation test device in which a third fold 13 having the same shape as these folds 11 and 12 is slidably fitted into the case 8, the first and second electrodes are positioned between the first and second electrodes. The flashover value characteristics when positive and negative impulse voltages are applied between 9 and 10 are expressed by the second fold 12 and the third fold 13 on the horizontal axis.
In FIG. 4, the distance 1 (m/m) between the 50% impulse flashover voltage and 50% FOV (KV) is plotted on the vertical axis, as shown by curves A and B.

In addition, in FIG. 4, curves C and D indicate the case where a positive polarity impulse and a negative polarity impulse are applied between the electrodes 9 and 10 only by the third fold 13 without using the first and second folds 11 and 12. The flashover value characteristics and the straight lines E and F when the positive polarity impulse and the negative polarity impulse are applied to both electrodes 9, 13 without using any of the folds 11, 12, 13,
This shows the flashover value characteristics when applied for 10 minutes.

In addition, by using the above-mentioned simulation test device, as shown in FIG.
Between 1 and 12, there is one more, the third of two.
The folds 13a and 13b are slidably fitted into the case 8, and between the first fold 11 and the third fold 13a on one side (the left side in FIG. 5) and between the second fold 12 and the other fold. Flash when the distances l and l between the third fold 13b and the third fold 13b are changed while keeping them equal, and impulse voltages of positive polarity and negative polarity are applied between the first and second electrodes 9 and 10. The fold value characteristics are expressed by the first and second folds on the horizontal axis.
Fig. 6 shows the distance l (m/m) between 1, 12 and each third fold 13a, 13b, and the 50% impulse flashover voltage 50% F, O, V (KV) on the vertical axis. It became as shown by curves A and B.

Therefore, by providing one pleat near each end of the dielectric case 8 and at least one pleat near the middle of these pleats, the creeping flash value can be dramatically increased. It turns out that it can be improved.

Furthermore, the relationship between the thickness of the coating 2a and the creeping flash value is as shown in FIGS. 7 and 8.
A rectangular conductor (5 x 50 m/m) partially covered with a covering tube 14 of ~2 m/m is connected to one electrode 15.
At the same time, this electrode 15 is covered with an insulating tube 16 made of synthetic resin and having an inner diameter of 80 m/m.
As shown in FIG. 9, the results of an experiment were carried out using a simulation apparatus in which the second electrode 17 was fitted concentrically so as to overlap with each other, and the second electrode 17 was movably fitted around the outer periphery of the insulating cylinder 16. Summer. That is, in FIG. 9, the horizontal axis represents the distance L (m/m) between the end of the insulating cylinder 16 and the second electrode 17, and the vertical axis represents the 50% impulse flashover voltage, 50% FOV (KV). Curves A and B indicate that the wall thickness t of the insulating cylinder 16 is 5.
m/m, and when positive and negative impulses are applied between the first and second electrodes 15 and 17,
In addition, curves C and D indicate that the wall thickness t of the insulating cylinder 16 is 25
m/m, and when impulses of positive and negative polarity are applied between both electrodes 15 and 17, curves E and F are obtained when the thickness t of the insulating cylinder 16 is 45 m/m and the electrodes 15 and 17 are This shows the flashover value characteristics when impulses of positive polarity and negative polarity are applied between them.

The relationship between the wall thickness t of the insulating cylinder 16 and the flash voltage (flash value) V is as follows: (C: specific capacitance, l: interelectrode distance, K _b : constant), which satisfies Toepler's general formula,
In addition, considering the experimental results and the experimental results described above, each pleat 11, 12, 13, 13
a, 13b can be handled in the same way as case 8 with a uniformly increased wall thickness, and each pleat 11,
By increasing the outer diameter of 12, 13, 13a, and 13b, the length of the case 8 is shortened, in other words, by increasing the outer diameter of each of the first, second, and third pleats 5, 6, and 7. This makes it possible to reduce the length of the covering 2a and, in turn, to downsize the power distribution board and the like.

As described above, the present invention provides, in an insulated conductor supported by a grounding fixing system via an insulated support member, first folds and first folds on the outer periphery near the end of the covering of the insulated conductor and near the insulated support member. In addition to providing two pleats, a third pleat is provided near the middle between the first pleat and the second pleat, so the distance between the end of the covering and the insulating support member is significantly reduced. This has the effect of dramatically downsizing the power distribution board and the like.

[Brief explanation of the drawing]

Fig. 1 is a partially omitted front view of an insulated conductor according to the present invention, and Figs. 2 and 3 are a partially cutaway front view and an end view of a simulation experiment device with three pleats, respectively. Fig. 4 is an explanatory diagram of the flashover value characteristics when the experiment is conducted with three pleats, Fig. 5 is a partially cutaway front view of the simulated experimental device when the number of pleats is four, and Fig. 6 Figure 7 is an explanatory diagram of the flashover value characteristics when the experiment is conducted with four pleats, and Figures 7 and 8 are a front cross-sectional view and an end view of a simulation experimental device for measuring the flashover value with respect to the wall thickness of the insulating tube, respectively. ,
FIG. 9 is an explanatory diagram of the flashover value characteristics with respect to changes in the wall thickness, etc. of the insulating cylinder. 2... Conductor, 2a... Covering, 3... Grounding fixing system, 4... Insulating support member, 5... First pleat, 6
...Second fold, 7...Third fold.

Claims (1)

[Claims] 1. In an insulated double conductor supported by a grounding fixed system via an insulating support member, first folds and second folds are provided near the end of the covering of the insulated conductor and on the outer periphery near the insulated support member. In addition, an insulated coated conductor characterized in that a third pleat is provided near an intermediate portion between the first pleat and the second pleat.