JP4514591B2 - Gas insulated switchgear - Google Patents

Description

  The present invention relates to a gas-insulated switchgear having a storage device such as a lightning arrester, and more particularly to a gas-insulated switchgear that can facilitate inspection work.

  In a power receiving / distributing device such as a gas-insulated switchgear, a lightning arrester is housed from overvoltage protection and installed at a power receiving point.

  Conventionally, since a lightning arrester cannot withstand a withstand voltage test voltage imposed on a gas-insulated switchgear, it is known that the arrester itself is disconnected from a main circuit during a withstand voltage test (see, for example, Patent Document 1). .) This is because the lightning arrester itself absorbs overvoltage, so it is not necessary to withstand a test voltage that is higher than the working voltage.

  Further, as a method for preventing the test voltage from being applied, it is known to provide a disconnecting device between the lightning arrester and the main circuit and to open the disconnecting device during a withstand voltage test (for example, see Patent Document 2).

In such a lightning arrester, since it is not possible to carry out characteristic tests such as withstand voltage characteristics at the time of shipment from the factory and operation start voltage characteristics (measurement of V _{1 mA} at DC voltage, etc.) in a gas-insulated switchgear, We are carrying out. Similarly, at the time of inspection after installation, the lightning arrester has been removed because it cannot be carried out in the state of being incorporated in the gas-insulated switchgear.
Japanese Patent Laid-Open No. 10-308143 (second page, FIG. 3) Japanese Utility Model Publication No. 2-26313 (Fig. 2)

  The conventional gas insulated switchgear described above has the following problems.

  In the withstand voltage test of the gas-insulated switchgear at the time of factory shipment or inspection, it is difficult to carry out the characteristic test of the arrester itself, although the arrester can be separated from the main circuit. For this reason, at the time of the characteristic test, it was necessary to remove the lightning arrester from the box body of the gas-insulated switchgear in which the insulating gas was sealed. Therefore, it is necessary to process the insulating gas in the box, and it takes a lot of time to prepare gas processing equipment.

  On the other hand, there is a method of providing a disconnector for inspection and a bushing for inspection in the box, and disconnecting the lightning arrester from the main circuit with the disconnector for inspection, and switching to the inspection bushing to check the lightning arrester, but the number of storage devices increases, Gas insulated switchgear will be expensive and large.

  For this reason, it has been desired that the lightning arrester can be easily removed from the box body of the gas-insulated switchgear without performing gas treatment at the time of inspection.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a gas insulated switchgear that can remove a lightning arrester and facilitate inspection work without performing gas treatment.

In order to achieve the above object, a gas-insulated switchgear according to the present invention divides a metal box, and the box into a gas chamber and an air chamber in which insulating gas is enclosed to store storage equipment. An open end is hermetically fixed to the partition plate and an opening provided in the gas chamber and provided in the partition plate, and connected to the main circuit of the storage device at the other end facing the open end. an insulating cylinder main circuit electrodes are embedded that the includes a said main circuit electrodes in the insulation tube and detachably connected thereto arrester, in the insulation barrel Ri insulating der aerial, the insulation barrel axis The outer circumferential end of the insulating cylinder is L1 in which the creeping distance of the insulating cylinder is arranged substantially parallel to the side wall of the box body and spaced apart from the side wall, and the insulating cylinder is orthogonal to the axial direction. Gas gap from the side wall perpendicular to the axial direction to L When, in the longitudinal direction of the creepage distance of the insulating tube as well as longer than L1, characterized in that the L1 = L2.

  According to the present invention, the non-voltage-resistant device is accommodated in the insulating cylinder that divides the insulating gas from the air and connected to the main circuit in the box. It can be taken out of the box to facilitate inspections such as characteristic tests.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a gas-insulated switchgear according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a side view showing a lightning arrester portion of a gas-insulated switchgear according to Embodiment 1 of the present invention in a cut-away section, and FIG. 2 is a characteristic of the lightning arrester of the gas-insulated switchgear according to Embodiment 1 of the present invention. It is a figure explaining a test.

  As shown in FIG. 1, the gas-insulated switchgear is divided into an upper gas chamber 1a and a lower air chamber 1b with a partition plate 2 in the upper and lower intermediate parts of the box 1 made of metal as a boundary. It is configured.

  In the gas chamber 1 a, for example, an annular first insulating cylinder 3 having a U-shaped cross section formed of an epoxy resin is provided on the back side of the box 1. The open end of the first insulating cylinder 3 is airtightly fixed to the opening hole provided in the partition plate 2 by the first pressing plate 4. The main circuit electrode 5 is hermetically embedded at the other end facing the open end with both ends exposed to the outside and the inside of the first insulating cylinder 3.

  In the first insulating cylinder 3, for example, an annular second insulating cylinder 6 having a U-shaped cross section formed of an epoxy resin is mounted. A connection fitting 7 is embedded at the other end facing the open end of the second insulating cylinder 6 so as to be detachably connected to the main circuit electrode 5.

  A zinc oxide element 8 that absorbs overvoltage and a presser fitting 9 are housed in the second insulating cylinder 6 and are fixed by a sealing plate 10 whose open end is at the ground potential. A flange portion 6 a that protrudes in an annular shape is formed at the outer intermediate portion of the second insulating cylinder 6, and is fixed to the partition plate 2 by a second presser plate 11.

  These second insulating cylinder 6, connection fitting 7, zinc oxide element 8, presser fitting 9 and sealing plate 10 constitute a lightning arrester. Since this lightning arrester cannot withstand the withstand voltage test voltage imposed on the gas insulated switchgear, it is defined as a non-withstand voltage device.

  An insulating gas 12 such as SF6 gas is enclosed in a space portion outside the first insulating cylinder 3 in the box 1. In the space between the first insulating cylinder 3 and the second insulating cylinder 6, air similar to the air chamber 1b is sealed.

  A connection conductor 13 is fixed to the main circuit electrode 5 outside the first insulating cylinder 3 and is connected to a cable head 14 fixed to the side wall 1 c on the back side of the box 1. In addition, the cable head 14 is connected to storage devices such as a disconnector 15 disposed in an intermediate portion in the box 1, a circuit breaker 16 disposed on the front side, and a bus 17 disposed on the ceiling side. .

  The air chamber 1b is provided with an operation mechanism 18 for operating the disconnector 15 and the circuit breaker 16.

  Here, the first insulating cylinder 3 is arranged such that the axial direction is substantially parallel to the side wall 1c. The creeping distance in the radial direction of the first insulating cylinder 3, that is, the creeping distance of the first insulating cylinder 3 orthogonal to the axial direction of the first insulating cylinder 3, is L1, and the first insulating cylinder 3 When the gas gap from the outer peripheral end to the side wall 1c, that is, the gas gap from the outer peripheral end of the first insulating cylinder 3 to the side wall 1c orthogonal to the axial direction is L2, the gas gap L2 = (0.75 to 1.25). ) × Creepage distance L1.

  When the gas gap L2 is less than L2 = 0.75 × the creepage distance L1, the electric field strength along the creepage of the first insulating cylinder 3 is greatly increased, and the withstand voltage characteristic between the main circuit electrode 5 and the side wall 1c is the creepage distance L1. This is much lower than the characteristic obtained by adding the gas gap L2. When the gas gap L2 exceeds L2 = 1.25 × the creepage distance L1, the withstand voltage characteristic between the main circuit electrode 5 and the side wall 1c is increased, but the gas gap L2 is widened and the depth dimension of the box 1 is increased. Therefore, it is not preferable.

  When the creepage distance L1 and the gas gap L2 are substantially the same, the withstand voltage characteristic is greatly increased, and the depth dimension of the box 1 can be reduced, which is most preferable. For example, when the rated voltage is 60 kV, the creeping electric field of the first insulating cylinder 3 is suppressed by setting the gas gap L2 to 100 mm and the creeping distance L1 to 100 mm (the outer diameter of the first insulating cylinder 3 is approximately 200 mm). As a result, the withstand voltage characteristic is greatly increased, and the depth dimension of the box 1 can be reduced. Note that the creeping distance in the longitudinal direction of the first insulating cylinder 3 parallel to the axial direction is longer than the creeping distance L1.

  Next, a case where the second insulating cylinder 6 is removed from the box 1 and inspection is performed will be described with reference to FIG.

  When removing the lightning arrester, if the second presser plate 11 fixed to the partition plate 2 is removed, the inside of the first insulating cylinder 3 is in the air, so that the gas treatment is unnecessary and the second insulating cylinder 6 is attached. It can be pulled out.

  A power supply device 20 can be connected between the connection fitting 7 and the sealing plate 10 outside the box 1 to the drawn second insulating cylinder 6. The power supply device 20 can generate not only a DC voltage but also an AC voltage or a pulsed voltage. Then, a lightning arrester characteristic test such as a withstand voltage characteristic and an operation start voltage characteristic of the zinc oxide element 8 can be easily performed. After the characteristic test is finished, the second insulating cylinder 6 is mounted in the first insulating cylinder 3 and fixed by the second presser plate 11.

  According to the gas-insulated switchgear of the first embodiment, the first insulating cylinder 3 for separating the insulating gas 12 and the air is provided in the box 1, and the inside of the first insulating cylinder 3 on the air side is provided. Since the lightning arrester is attached to the battery, it is possible to remove the lightning arrester without performing gas treatment during the inspection, thereby facilitating the inspection work.

  Next, a gas insulated switchgear according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a side view showing the lightning arrester portion of the gas-insulated switchgear according to the second embodiment of the present invention cut away and shown in cross section. The second embodiment is different from the first embodiment in that a pleat is provided on the inner surface of the second insulating cylinder. In FIG. 2, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 2, a pleat 3 a is provided on the inner surface of the first insulating cylinder 3 that is air-insulated so that the creepage distance between the main circuit electrode 5 and the partition plate 2 is extended. Thereby, insulation characteristics, such as pollution, can be improved.

  According to the gas-insulated switchgear of the second embodiment, in addition to the same effects as those of the first embodiment, it is possible to improve insulation characteristics such as contamination of the inner surface of the first insulating cylinder 3 that is air-insulated.

  In addition, this invention is not limited to the said Example, In the range which does not deviate from the summary of invention, it can implement in various deformation | transformation. In the above embodiment, the lightning arrester is used as the storage device for the gas-insulated switchgear. However, the grounding-type instrument transformer is a non-voltage-resistant device that cannot withstand the withstand voltage test voltage imposed on the gas-insulated switchgear. Can also be used.

The side view which cuts and shows the lightning arrester part of the gas insulation switchgear which concerns on Example 1 of this invention. The figure explaining the characteristic test of the lightning arrester of the gas insulation switchgear which concerns on Example 1 of this invention. The side view which cuts off and shows the lightning arrester part of the gas insulation switchgear which concerns on Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Box 1a Gas chamber 1b Air chamber 1c Side wall 2 Partition plate 3 1st insulation cylinder 3a Fold 4 1st holding plate 5 Main circuit electrode 6 2nd insulation cylinder 6a Flange part 7 Connection metal fitting 8 Zinc oxide element 9 Presser fitting 10 Sealing plate 11 Second presser plate 12 Insulating gas 13 Connecting conductor 14 Cable head 15 Disconnector 16 Breaker 17 Busbar 18 Operating mechanism 20 Power supply

Claims (1)

A metal box,
A partition plate that divides the inside of the box into a gas chamber and an air chamber for containing a storage device by enclosing an insulating gas;
A main circuit electrode provided in the gas chamber and having an open end hermetically fixed to an opening provided in the partition plate and connected to the main circuit of the storage device at the other end facing the open end An insulating cylinder embedded with
A lightning arrester detachably connected to the main circuit electrode in the insulating cylinder,
The inner insulation barrel Ri insulation der in the air,
The insulating cylinder is arranged with the axial direction being substantially parallel to the side wall of the box and spaced apart from the side wall,
The creeping distance of the insulating cylinder in which the insulating cylinder is orthogonal to the axial direction is L1,
When the gas gap from the outer peripheral end of the insulating cylinder to the side wall orthogonal to the axial direction is L2,
A gas insulated switchgear characterized in that the creeping distance in the longitudinal direction of the insulating cylinder is longer than L1 and L1 = L2 .

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