JPS6112325B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an insulating device for a high voltage conductor, and more particularly to an insulating device for electrically insulating a high voltage conductor passing loosely through a hole in a wall at ground potential.

Conventionally, in order to insulate a high-voltage conductor that passes through a hole in the wall at earth potential in electrical equipment, such as a busbar penetrating the bulkhead of a switchboard or a connection conductor led out from the machine frame of a switchgear, it is necessary to The part corresponding to the hole is covered with an insulating heat-shrinkable tube, but as the insulation class increases, the diameter of the hole into which the high-voltage conductor is loosely fitted has to be increased, leading to an increase in the size of the electrical equipment itself. are doing.

To deal with this problem, the high-voltage conductor that penetrates the wall at earth potential has been replaced with molded bushings, porcelain bushings, or capacitor bushings, but such bushings are expensive, so they reduce the price of electrical equipment. There is a problem with rising prices.

The present invention has been made in view of the above-mentioned problems, and its object is to position a high-voltage conductor that freely passes through a hole in a wall of an electrical device at an earth potential at a portion corresponding to the hole in the wall. By surrounding it with a fitted cylindrical insulator, and by making the gap between the end of this insulator and the wall at earth potential equal to or larger than the hole diameter of the wall, the earth potential can be adjusted according to the insulation class. It is an object of the present invention to provide an insulating device that can optimize the hole diameter of a wall, and has a simple structure and a low cost. Embodiments of the present invention will be described in detail below with reference to the drawings.

1 and 2 are a front view and a side sectional view of a first embodiment of an insulating device according to the present invention. In the figure, 1 is a high-voltage conductor made of a rectangular copper rod that passes freely through a hole 3 in a wall 2 at earth potential in electrical equipment, such as a bus bar passing through a partition wall of a closed switchboard or a connecting conductor led out from a machine frame of a switchgear. , its outer periphery is covered with an insulating heat-shrinkable tube 4 made of ethylene propylene having a predetermined thickness, which constitutes a part of the insulating device according to the present invention, and the holes in the wall 2 are covered with Bakelite, which is an insulating material. A cylindrical barrier 5 formed in a cylindrical shape having a diameter suitably smaller than the diameter (hole diameter) Φ of wall 2 is fitted so as to be inserted through the hole 3 of the wall 2. The protruding length of the cylindrical barrier 5, that is, the gap between its end and the side surface (wall surface) 2a of the wall 2, is at least equal to or greater than the hole diameter Φ. The length, ie, the distance L between the end and the wall surface 2a, is also approximately the same as that of the cylindrical barrier 5.

Here, the high voltage conductor 1 is a flat rectangle (5 x 50 m/
m) Using a copper rod, hole diameter Φ as wall 2 of earth potential
Grounded rectangular shape (300×
300 m/m) using an iron plate, a tube made of ethylene propylene having a thickness of 2 to 3 m/m as the heat shrink tube 4, and a tube made of Bakelite with an inner diameter of 100 m/m and a thickness of 5 m/m as the cylindrical barrier 5. The experimental results of the flashover value characteristics when using a cylinder and changing the protrusion length L of the heat shrinkable tube 4 and setting the protrusion lengths of the cylindrical barrier 5 to 60 m/m, 120 m/m and 180 m/m are as follows. The curves A, B, and C are shown in FIG. 3, in which the horizontal axis represents the protruding length L of the heat shrink tube 4, and the vertical axis represents the 50% impulse flashover voltage 50% FOV.

Therefore, the protruding length of the cylindrical barrier 5 =
In the case of 60 m/m, it can be seen that the heat-shrinkable tube 4 has an insulating effect, and it can also be seen that the withstand pressure becomes saturated when the protruding length exceeds the hole diameter Φ = 170 m/m.

In addition, as the high voltage conductor 1, a rectangular (5 x 50 m/m)
Using a copper rod, the hole diameter Φ is used as the ground potential wall 2.
Grounded rectangular shape (470×
470 m/m) using an iron plate, using an ethylene propylene tube with a thickness of 2 to 3 m/m as the heat shrink tube 4, and using a Bakelite cylinder as the cylindrical barrier 5, changing the protrusion length L of the heat shrink tube 4. In addition, the protruding length of the cylindrical barrier 5 is 60 m/m, 100 m/m, and 120 m/m, and the inner diameter of the protruding length = 60 m/m is
60m/m (o mark), 80m/m (△ mark) and
Change it to 90m/m (x mark), protrusion length =
The experimental results of the flashover value characteristics when the inner diameter of a tube of 100 m/m is 80 m/m and the inner diameter of a tube with a protrusion length of 120 m/m are 80 m/m. The horizontal axis shows the protrusion length L of the heat shrink tube 4. , the fourth with 50% impulse flashover voltage and 50% FOV on the vertical axis.
The curves are now shown as curves A, B and C in the figure.

Therefore, the dielectric strength has almost no effect on the outer diameter of the cylindrical barrier 5, and as in the case of the heat-shrinkable tube 4, the protruding length of the cylindrical barrier 5 depends on the hole diameter Φ of the wall 2 at ground potential. It turns out that it becomes saturated.

Furthermore, as in the case of Fig. 3, a rectangular (5 x 50 m/m) copper rod is used as the high voltage conductor 1, and a grounded rectangular (300 m/m) hole 3 with a hole diameter of 170 m/m is used as the earth potential wall 2. x 300 m/m) using an iron plate, using an ethylene propylene tube having a thickness of 2 to 3 m/m as the heat shrink tube 4, and using a Bakelite cylinder as the cylindrical barrier 5,
The protrusion length L of the heat-shrinkable tube 4 and the protrusion length of the cylindrical barrier 5 are changed while keeping them both at the same protrusion length, and the inner diameter of the cylindrical barrier 5 is changed, and positive and negative impulses are generated. The experimental results of the flashover value characteristics when .
In Fig. 5, in which the vertical axis shows the protrusion length L, and the 50% impulse flashover voltage 50% FOV, curve A (positive polarity impulse application (hereinafter referred to as "positive polarity"), cylindrical barrier inner diameter (hereinafter referred to as "positive polarity"), B (positive polarity, inner diameter 100m/m), B (positive polarity, inner diameter 100m/m)
m), C (positive polarity, inner diameter 140 m/m), D (negative polarity impulse application (hereinafter referred to as "negative polarity"), inner diameter
60m/m), E (negative polarity, inner diameter 80m/m), F (negative polarity, inner diameter 100m/m), G (negative polarity, inner diameter
120m/m) and H (negative polarity, inner diameter 140m/m)
It became as shown in .

Therefore, whether the insulation resistance varies due to a change in the inner diameter of the cylindrical barrier 5 or the protruding length L of the heat-shrinkable tube 4 and the cylindrical barrier 5 depends on the hole diameter Φ of the wall 2
It can be seen that by being equal to 170 m/m, saturation is achieved for positive and negative polarity impulses. Note that when the protrusion length L of both becomes larger than the hole diameter Φ, the withstand pressure is seen to decrease somewhat, but it should be considered that it is saturated, and there is no effect of the positive or negative polarity of the impulse. it is conceivable that.

6 and 7 are a front view and a side sectional view of a second embodiment of the insulating device according to the present invention. In this embodiment, a second cylindrical barrier 6 made of Bakelite and formed into a cylindrical shape is fitted concentrically on the outer periphery of the cylindrical barrier 5 in the first embodiment described above. Since this is a double structure and the other configurations are the same as those of the first embodiment, the same reference numerals are given to the constituent members that perform the same functions, and the explanation thereof will be omitted.

The experimental results of the flashover value characteristics of this second embodiment show that the high voltage conductor 1, the wall 2 having the hole 3, the heat shrink tube 4, the first cylindrical barrier 5, etc. are set almost the same as in the case of FIG. While keeping the heat shrink tube 4 and the first and second cylindrical barriers 5 and 6 at the same protrusion length, the protrusion length L is changed, and the first and second cylindrical barriers are When the inner diameters of the tubes 5 and 6 are changed and impulses of positive and negative polarity are applied, the horizontal axis represents the protrusion length L of the heat shrink tube 4 and the first and second cylindrical barriers 5 and 6, and the vertical axis In Fig. 8, with a 50% impulse flashover voltage and 50% FOV on the axis, curve A (positive polarity impulse application (hereinafter referred to as "positive polarity"), inner diameter of the first and second cylindrical barriers (hereinafter referred to as "each (inner diameter) 80, 100m/m), B (positive polarity, each inner diameter 90, 110m/m), C (positive polarity, each inner diameter
100, 120m/m), D (negative polarity impulse application (hereinafter referred to as "negative polarity"), each inner diameter 60, 80m/
m), E (negative polarity, each inner diameter 90, 110 m/m) and F (negative polarity, each inner diameter 120, 140 m/m).

Therefore, in the case of the second embodiment, as in the experimental example shown in FIG. The protrusion length L, is the hole diameter Φ=
170m/m, it can be seen that both positive polarity impulses and negative polarity impulses are saturated, and by making the cylindrical barrier double, it is more effective than a single cylindrical barrier. It can be seen that the withstand pressure increases.

9 and 10 are a front view and a side sectional view of a third embodiment of an insulating device according to the present invention. This embodiment has a third cylindrical barrier 7 formed in a cylindrical shape from Bakelite on the outer periphery of the second cylindrical barrier 6 in the second embodiment described above.
The cylindrical barriers are fitted concentrically and the cylindrical barriers are triple layered.The other structure is the same as that of the second embodiment, so the same reference numerals are given to the constituent members that perform the same function, and the explanation thereof will be explained below. Omitted.

The results of a comparison experiment of the flashover value characteristics of this third embodiment and those of the first and second embodiments described above show that the high voltage conductor 1 and the earth potential wall 2 having holes 3 are Setting the heat shrink tube 4 and the first, second, and third cylindrical barriers 5, 6, and 7 in almost the same way as in the case, while maintaining the same protrusion length L, When changed, the horizontal axis shows the protrusion length L of the heat shrink tube 4 and the first, second, and third cylindrical barriers 5, 6, 7, and the vertical axis shows 50
In Figure 11, which has a FOV of 50% impulse flashover voltage, curves A (inner diameter of cylindrical barrier 5 (hereinafter referred to as "inner diameter") 80 m/m) and B (inner diameter 100 m) are for a single cylindrical barrier. /m) and C (inner diameter 120m/m), and the curve D (first,
The inner diameter of the second cylindrical barriers 5 and 6 (hereinafter referred to as "each inner diameter")
) 80, 100m/m), E (each inner diameter 90,
110m/m) and F (each inner diameter 100, 120m/m)
In addition, a triple layered cylindrical barrier is shown in curve G (the inner diameters of the first, second, and third cylindrical barriers 5, 6, and 7 are 80, 100, and 120 m/m). Ta.

Therefore, it can be seen that the dielectric strength can be improved by increasing the number of cylindrical barriers, and in any of the embodiments, the heat shrinkable tube 4, the cylindrical barrier 5, which is made of an insulator,
It has been found through experiments that when the distance L between the end portions 6 and 7 and the wall surface 2a is equal to or more than 1.5 times the hole diameter Φ of the wall 2, good withstand voltage characteristics are exhibited.

In addition, in each of the above-mentioned examples, when the cylindrical barrier alone was changed to 1 to 3 layers without using the heat shrink tube, the pressure resistance characteristics were almost the same as when the heat shrink tube was used in combination.

As can be seen from the above embodiments, in order to insulate the high voltage conductor 1 that loosely passes through the hole 3 in the wall 2 at earth potential in electrical equipment, a heat shrink tube is used to 4 only, 1
The insulating device can be constructed by arbitrarily selecting a cylindrical barrier with two or three layers. Note that the cylindrical barrier is double-layered and triple-layered.
As can be seen from Figure 1, there is not much difference, so in order to achieve high pressure resistance, it is better to choose a double cylindrical barrier type from a cost perspective.

FIG. 12 and FIG. 13 show the support structure of the cylindrical barrier in the insulating device of each of the embodiments described above.
This is an example of a heavy weight. That is, the cylindrical barrier is supported by interposing a plurality of curved plate-shaped spaces 8 made of an insulating material at positions corresponding to the holes 3 in the wall 2 between the first cylindrical barrier 5 and the second cylindrical barrier 6. The second cylindrical barrier 6 is attached to the wall 2 by a plurality of supports made of insulators, and the second cylindrical barrier 6 is attached to the wall 2 by fasteners 9 made of bolts and nuts. This is done by member 10.

As described above, the present invention insulates a high-voltage conductor passing loosely through a hole in a wall at earth potential, and fitting a cylindrical insulator to the high-voltage conductor so as to pass through the hole in the wall. In addition, since this is an insulating device in which the distance between the end of the insulator and the wall surface is equal to or more than 1.5 times the hole diameter of the wall, the protruding length of the insulator can be set appropriately for the hole diameter, and as a result, electrical equipment can be reduced. Moreover, the structure of the insulating device can be simplified and its cost can be significantly reduced.

[Brief explanation of the drawing]

1 and 2 are respectively a front view and a side sectional view of the first embodiment of the present invention, and FIGS. 3, 4, and 5 are explanatory diagrams of flashover value characteristics of the first embodiment, respectively. , FIG. 6 and FIG. 7 are respectively a front view and a side sectional view of the second embodiment of the present invention, and FIG.
The figure is an explanatory diagram of the flashover value characteristics of the second embodiment, FIGS. 9 and 10 are a front view and a side sectional view of the third embodiment of the present invention, respectively, and FIG. An explanatory diagram comparing the flashover value characteristics of the third embodiment, FIG. 12 is a side sectional view of the support structure of the cylindrical barrier in the insulating device according to the present invention, and FIG. 13 is a cross section taken along the line X-X in FIG. 12. It is a diagram. 1... High voltage conductor, 2... Wall, 3... Hole, 4...
Heat shrink tube, 5, 6, 7...Cylindrical barrier.

Claims (1)

[Claims] 1. A high-voltage conductor passing loosely through a hole in a wall at earth potential is insulated, and a cylindrical insulator is fitted to the high-voltage conductor so as to pass through the hole in the wall, and the insulator is An insulating device for a high voltage conductor, characterized in that the gap between the end and the wall is equal to or more than 1.5 times the diameter of the hole in the wall.