JPH0461451B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an insulating spacer used in gas-insulated switchgear, pipeline air power transmission equipment, etc. using SF ₆ gas or the like as an insulating medium.

[Background technology of the invention and its problems]

In gas-insulated switchgear and pipeline aerial power transmission equipment, high-voltage conductors are insulated and supported within a grounded metal container.
Many insulating spacers are used. This insulating spacer supports a high voltage conductor with an insulating spacer body made of thermosetting synthetic resin such as epoxy resin, as shown in, for example, Japanese Patent Publication No. 54-44106 and Japanese Patent Application Laid-Open No. 55-155512. A filler metal for the mounting bolt is embedded in the flange.
Furthermore, since SF ₆ gas tends to deteriorate its insulation properties due to unequal electric fields, as a countermeasure to this, a grounding shield is integrally embedded around the high voltage conductor, and this potential is connected to a grounding pad that also serves as the mounting bolt hole. Usually, this is secured through

FIG. 9 shows a longitudinal cross-sectional view of a conventional insulating spacer. 1 is a high voltage conductor, 2 is an insulating gas, 3 is a grounding container, and 4 is an insulating spacer body. High voltage conductor 1
The current-carrying member 41 that connects each other is cast integrally with the insulating spacer body 4. 6 is a metal flange, which is also cast integrally with the insulating spacer main body 4. 71 and 72 are conductive rings integrally cast into the insulating spacer main body 4, and 71 is always grounded to alleviate the electric field at the joint between the container 3 and the insulating spacer 40 and contribute to improving insulation performance. ing. 72 has a structure that allows the potential to float permanently or temporarily, and is used for voltage measurement of the high-voltage side charging section and corona measurement. In other words, when the metal ring 72 is floating in potential, the high voltage side A voltage proportional to the charging part voltage is induced.

By extracting this voltage to the outside through an opening provided in the metal flange 6 using a conductive member insulated from the metal flange 6, voltage detection of the high-voltage side live part, that is, voltage measurement and corona measurement, etc. can be performed. I can do it. However, this conventional insulating spacer has the following drawbacks.

That is, it is necessary to integrally cast the two metal rings together with the metal flange 6 inside the insulating spacer 4, which requires a lot of man-hours during casting, and the structure becomes complicated, resulting in high costs. Become.

Furthermore, integrally casting a plurality of small metal rings into an insulator is not favorable mechanically, especially in terms of thermal stress, and may cause cracks. Therefore, it has been desired that the number of metal rings that are integrally cast within the insulator be the minimum necessary.

[Purpose of the invention]

The present invention was made in view of the above problems, and aims to provide an insulating spacer that has a simple structure, is easy to manufacture, and is capable of measuring surge voltage, etc., which is preferable in terms of mechanical stress. .

[Summary of the invention]

In order to achieve the above object, the present invention has a structure in which the insulating spacer main body and the metal flange are separated, a grounding shield is embedded in the insulating spacer main body, and terminals are connected to the outside of the insulating spacer main body from two places of the grounding shield. Furthermore, the center angle between these two terminals and the central axis of the insulating spacer body is approximately 80° or more and approximately 120° or less.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 8.

Components that are the same as those shown in FIG. 9 are designated by the same reference numerals. In FIG. 1, a high voltage conductor 1 is supported and arranged in a grounded container 3 filled with an insulating gas 2 via an insulating spacer 40. Usually, a connecting flange 5 is provided at the end of the grounding container 3 to connect the grounding containers 3 to each other. The insulating spacer 40 supports and arranges the high voltage conductor 1 in the grounding container 3 in such a manner that it is sandwiched between the connecting flanges 5. The insulating spacer 40 is composed of a metal flange 6 which is held between connecting flanges 5 and an insulating spacer main body 4 that is engaged with the metal flange 5, and is manufactured separately instead of being manufactured by integrally casting them as in the past. It is manufactured separately and then incorporated as an integral part when assembling the equipment. Incidentally, the insulating spacer body 4 and the connecting flange 5 are joined via an O-ring 31 to maintain gas tightness.

A partially cut out annular protrusion 4a is provided on the outer periphery of the insulating spacer main body 4 at an intermediate portion in the thickness direction, while a protrusion 6a is provided on one side of the inner periphery of the metal flange 6. . Here, the protruding portion 4a has a structure in which notches are provided at four equally divided locations on the circumference.

As shown in FIG. 2, the insulating spacer body 4 has
A ground shield 71 is embedded concentrically with the conductor 1. Four metal fittings 8a, 8b, 10a, 10b are connected to this grounding shield 71.
As shown in FIG. 3, the metal fittings 8a, 8b are made to protrude outside from the notch of the protrusion 4a provided on the outer periphery of the insulating spacer main body 4, and the metal fittings 10a, 1
0b is also manufactured so as to protrude outward from the notch of the protruding portion 4a, but as a product, it is processed so that it does not protrude outward from the outer surface of the insulating spacer main body 4. That is, the metal fittings 8a, 8b, 10a, 10b are
When the insulating spacer body 4 and the grounding shield 71 are integrally cast, this is used as a support to support the grounding shield 71 in the mold, and both metal fittings 8 and 10 are used in the state after integral casting. It protrudes from the outer surface of the insulating spacer 4. Therefore, both metal fittings 8 and 10 are in the same state before processing.
Next, the protruding parts of the metal fittings 10a and 10b from the outer surface of the insulating spacer 4 are scraped off, and the cut surfaces are made of the insulating material 1.
Covered with 00. This state is shown in FIG. On the other hand, holes are made in the metal flange 6 located where the metal fittings 8a and 8b protrude. The central angle θ formed by the metal fittings 8a and 8b is 90° in the illustrated embodiment, but the central angle θ is 80° or more and 120°.
The following shall apply.

On the other hand, the mounting structure of the insulating spacer main body 4 and the metal flange 6 shown by A in FIG. 2 is integrated with a stopper 9 between them as shown in FIGS. 5 and 6.
That is, the stopper 9 has a stepped portion 9a having an L-shaped cross section as is clear from FIG.
By tightening the bolts 12, the step 9a comes into contact with one side 4b of the protrusion 4a provided on the outer periphery of the insulating spacer main body 4, and the opposite side 4c contacts the step 6a of the metal flange 6.
The insulating spacer main body 4 and the metal flange 6 are fixed together by pressing strongly against them.

In the insulating spacer 40 having the above structure, the grounding shield 71 is normally connected to at least the terminals 8a and 8b.
is grounded by connecting one side to the metal flange 6, but when measuring voltage, the seventh
As shown in the figure, capacitors 21 of equal capacity are connected between the terminals 8a, 8b and the metal flange 6, respectively.
22 is connected, and the terminal voltage of the capacitor 21 is measured by the measuring device 20. Here, 23 and 24 are metal boxes that cover the capacitors 21 and 22 and the measuring device 20.
It is mechanically and electrically connected to the metal flange 6.

In the insulating spacer 40 configured in this way, when casting the insulating spacer main body 4, the grounding shield 71 and the supporting metal fittings 8a, 8b, 10a, 10
It is sufficient to fill in the minimum amount of b, which eliminates the need to cast a large amount of filler metal used in conventional flange tightening, which leads to improved work and stable quality improvement. Further, since the insulating spacer main body 4 and the metal flange 6 are made separately, their processing is very easy, and the use of the stopper 9 and the bottle 12 is enough to integrate the two. Furthermore, if the center angle of the metal fittings 8a and 8b is within the range of 80° to 120°, the insulating spacer body 4
It is possible to select the angle at which the efficiency of integrally molding the ground shield 71 and the ground shield 71 is the best, and the insulating spacer 40 is the least expensive. The reason for this will be explained next. In order to integrally mold the insulating spacer body 4 and the grounding shield 71, it is necessary to support the grounding shield 71 at three or more points in order to align the central axis of the insulating spacer body 4 with the central axis of the grounding shield 71. There is. It is desirable that all the supports used for this support are the same in terms of production efficiency, and that they are designed so that the same force is applied to each support point. For example, when using a support method in which a large force is applied only to one point, the strength of the support must be designed to match this maximum strength, and other support points are overdesigned and inefficient. In order to apply the same force to all the supports, the support points may be equally spaced, or four support points may be placed at the vertices of the rectangle. However, in the latter case, if the support points are placed at the vertices of an extremely elongated rectangle, it will be difficult to maintain balance, and if the support points shift even slightly, a large force will be applied to one of the support points. Therefore, in this case as well, it is desirable to have a rectangular shape as close to a square as possible, that is, a nearly equal arrangement. For example, if 3 points are evenly distributed, the central angle will be 120°, and if 4 points are equally distributed, the central angle will be 90°.
becomes. In addition, in the case of four-point support, it does not matter if the center angle deviates slightly from 90°. It can be seen that for these reasons, it is possible to select the optimum value for the central angle within the range of 80° to 120°.

On the other hand, the following three main effects can be obtained when performing voltage measurement, particularly surge measurement, using the above-described insulating spacer 40 of the present invention.

(1) Since the terminals 8a and 8b for measurement are installed in two places, the ground shield 71 will not become high voltage when installing the measuring device, and the gas insulated equipment will be safe for workers. It is also safe due to its reliability. That is, although the ground shield 71 is normally connected to the metal flange 6, the capacitors 21 and 22 are attached only when making measurements. At this time, if one terminal of 8a or 8b is connected to the metal flange 6 and a capacitor is attached to the other terminal, even if the connection with the metal flange 6 is removed afterwards, the ground shield 7
The potential of terminal 1 is suppressed by the capacitor, and the ground shield 71 does not impair its original role of mitigating the electric field.
Or, even if you touch the exposed part of 8b, you will not get an electric shock.

(2) When a light emitting diode is used as a surge measuring device, the intensity of the light emitted by it depends on the temperature, so in order to accurately measure the voltage, the temperature around the measuring device must be kept constant or temperature compensation must be performed. There is a need to. However, when the measuring instrument is irradiated with sunlight, the temperature of the measuring instrument increases, resulting in a considerable temperature difference compared to when it is not irradiated. Therefore, it is desirable that the measuring instrument is not exposed to sunlight.

As shown in Figure 8, for example, in Tokyo, at noon on the summer solstice, the sun is positioned at an angle of approximately 80° with respect to the horizontal plane. At this time, sunlight is irradiated in the direction of the arrow 28. Furthermore, at sunrise and sunset, sunlight is irradiated almost horizontally as shown by arrow 27. At this time, the shaded area 25 is always in the shade. Therefore, it is desirable that the measuring device be located in this area. Some single-phase busbars have a diameter of about 1 m, and in this case, θ ₁ and θ ₂ are about 40° and about 60°, respectively, so that the central axis of a measuring instrument with a length of about 15 cm falls within the region 25. Therefore, from this point as well, the central angle of terminals 8a and 8b should be set at 80° or more.
The conditions are satisfied if the angle is 120° or less and the insulating spacer 40 is installed so that the intermediate portion of both terminals is located directly below. The number 26 is the earth.

(3) Since only the minimum necessary terminals 8a and 8b protrude from the outside of the insulating spacer main body 4, there is no need to attach many capacitors for measurement. When a large number of terminals protrude outside the insulating spacer body 4, if a capacitor is not installed here, the moment a surge occurs in the gas insulated switchgear, these terminals will become high potential and will be connected to the metal flange 6. cause electric discharge. This is because the ground shield acts as an inductance for waveforms with steep changes.

As described above, in addition to being effective in surge measurement, by arranging the terminals 8a and 8b facing downward, it is also possible to prevent rainwater from entering from the terminal portions.

〔Effect of the invention〕

As explained above, according to the present invention, the structure is simple, easy to manufacture, and has excellent mechanical stress.
Furthermore, it is possible to provide an effective insulating space when measuring surge voltage or the like.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an insulating spacer showing an embodiment of the present invention, Fig. 2 is a front view of the insulating spacer of Fig. 1, Fig. 3 is a sectional view taken along the line of Fig. 2, and Fig. 4. is a sectional view taken along the line in FIG. 2, FIG. 5 is an enlarged view of part A in FIG. 2, FIG. 6 is a sectional view taken along the line in FIG. FIG. 8 is a diagram showing the surge measuring method, and FIG. 8 is a diagram showing the relationship between a surge measuring device attached to an insulating spacer and sunlight irradiation, and FIG. 9 is a cross-sectional view of a conventional insulating spacer. DESCRIPTION OF SYMBOLS 1... High voltage conductor, 3... Grounding container, 4... Insulating spacer body, 5... Grounding container flange, 6...
...Metal flange, 8 (8a, 8b)...Metal fitting, 9
... Fastener, 10 (10a, 10b)... Supporting metal fitting, 20... Surge voltage measuring device, 40... Insulating spacer, 41... Current carrying member, 71, 72... Embedded shield.

Claims (1)

[Claims] 1. An insulating spacer body that insulates and supports a high-voltage conductor, and a metal flange disposed on the outer periphery of the insulating spacer body that is separated from the insulating spacer body that attaches this insulating spacer body between flanges of a grounded metal container; The shield has two conductive terminals protruding from the outer periphery of the insulating spacer body that are always connected to the metal flange and disconnected from the metal flange during measurement. An insulating spacer characterized in that the two conductive terminals are connected to each other and the central angle between the two conductive terminals and the central axis of the insulating spacer body is about 80° or more and about 120° or less.