JP6430280B2 - Gas insulated switchgear and gas replacement method thereof - Google Patents

Description

  Embodiments described herein relate generally to a gas insulated switchgear and a gas replacement method thereof.

  Many of the gas-insulated switchgears (hereinafter referred to as “GIS”) introduced to power transmission and distribution facilities in the early 1970s have come to a maintenance period, and improvement in maintainability is desired. .

  Generally, an insulating gas having high insulation performance is sealed in a GIS tank, but the moisture concentration in the gas has a great influence on the insulation performance. It is necessary to maintain below.

  Since the quality of the sealing performance of the connecting part of the tank has not been established as much as in the old GIS, on the assumption that gas leaks, for example, a circulation device for circulating gas outside the tank is provided. The tank was connected to the tank with piping to circulate the gas, and the moisture concentration of the gas was collectively managed by the circulation device (hereinafter referred to as “gas circulation method”).

  In the case of the gas circulation method, in addition to providing piping outside the tank, it is necessary to move an extra device called a circulation device, so maintenance problems such as problems of failure due to deterioration over time and an increase in gas leakage from the circulation system such as piping, It becomes a big problem.

  In addition, the current GIS has improved the reliability of the sealing performance of the tank, and the airtightness has been improved. A method (sealing method) in which an adsorbing device is attached to the part and the moisture content of the gas is managed is the mainstream.

JP 2004-129343 A

  In order to change a conventional gas-insulated switchgear of gas circulation type to a sealed-off type, it is necessary to attach an adsorption device to each tank, but there is no place to install an adsorption device in a gas circulation type tank For this reason, it is necessary to disassemble the equipment and remodel the tank. This remodeling will result in long-term facility shutdown and enormous costs.

  In addition, if an individual adsorption device is installed in the piping system connected to the current gas circulation tank and moisture management is performed, the cross-sectional area of the gas passage of the piping is small and the route to the adsorption device is long. Therefore, simply attaching an adsorption device to the gas passage of the pipe limits the moisture adsorption capacity, and a necessary moisture suppression effect cannot be expected.

  Furthermore, when trying to carry out construction for sealing off an existing gas insulated switchgear, it is necessary to temporarily stop gas circulation, collect the gas in the equipment, and replace it in the atmosphere. Contains much more moisture than the control value of the gas insulated switchgear, and a lot of moisture is absorbed in the equipment during the remodeling work, which makes it impossible to manage the moisture after sealing. .

  The problem to be solved by the present invention is that the high-pressure gas container of the gas-circulation-type insulated switchgear that is currently in operation can be switched to the sealed-off type without disassembling, and the maintenance and management of equipment including the subsequent moisture management Is to provide a gas-insulated switchgear and a gas replacement method thereof.

The gas insulated switchgear according to the embodiment includes a gas container, an air supply / exhaust port, and an adsorption device. The gas container is formed by connecting a plurality of cylindrical members having flanges at the ends by flanges. The air supply / exhaust port is for supplying / exhausting gas to / from the gas container, and is provided on the peripheral surface of the cylindrical member. The adsorption device is attached to the air supply / exhaust port. The adsorption device has a moisture adsorption chamber in which a moisture adsorbent is accommodated. The adsorption device includes a container, a first gas passage, and a second gas passage. The container contains a moisture adsorbent in a part of the moisture adsorption chamber. The first gas passage is provided on the wall surface between the moisture adsorbent accommodation position of the container and the air supply / exhaust port, and sucks and exhausts gas in the container through the moisture adsorption chamber. The second gas passage is provided on the contact surface between the container and the intake / exhaust port, and communicates the gas container with the moisture adsorption chamber.

  The gas replacement method of the embodiment includes a step of evacuating the gas supply / exhaust port of the gas container to recover the insulating gas sealed in the gas container, and after collecting the insulating gas, moisture management from the supply / exhaust port to the gas container A step of sealing the inert gas, a step of sealing the inert gas in the gas container, a step of attaching an adsorption device for sealing to the air supply / exhaust port, and evacuating the gas passage provided in the adsorption device A step of recovering the inert gas in the gas container; and a step of sealing a new insulating gas from the gas passage into the gas container after recovering the inert gas.

It is a figure which shows the structure of the gas insulated switchgear of embodiment. It is a block diagram which shows an example of the adsorption | suction apparatus of the gas insulated switchgear of FIG. It is a block diagram which shows the other example of a structure of an adsorption | suction apparatus. It is a figure which shows the cross section of an O-ring attachment location (part which the water | moisture content in air | atmosphere permeate | transmits). It is a figure which shows the structure of the gas insulated switchgear of the existing gas circulation system. It is a figure which shows a mode that the gas managed by the low moisture concentration is enclosed. It is a figure which shows a mode that a water | moisture content permeate | transmits in a high pressure gas container from the outside. It is a figure which shows the change of the moisture concentration in a high pressure gas container, when test operation (verification test) of a gas insulated switchgear is carried out.

  Hereinafter, embodiments will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of a gas insulated switchgear according to an embodiment, and FIG. 2 is a diagram showing an internal configuration of the adsorption device.

  As shown in FIGS. 1 and 2, the gas-insulated switchgear according to this embodiment includes an adsorption device 1, a high voltage conductor 2, a metal tank 3 as a tubular member, a piping boss 4, a compound meter 5, a switch 6, A high-pressure gas container 7, a valve 8, a spacer 9 as a support insulator, an O-ring 10 and the like are provided.

  A flange 3 a is provided at the end of the metal tank 3. The high-pressure gas container 7 is formed by connecting a plurality of metal tanks 3 with flanges 3 a or via spacers 9.

  At least one piping boss 4 having a piping boss gas passage 17 is provided on the peripheral surface of each metal tank 3. The pipe boss 4 (pipe boss gas passage 17) is a supply / exhaust port for supplying / exhausting gas such as gas or air to / from the high-pressure gas container 7. The suction device 1 is attached to the pipe boss 4. The internal configuration of the adsorption device 1 will be described with reference to FIG.

  The compound gauge 5 is a pressure gauge of the gas sealed in the high pressure gas container 7. The switch 6 issues an alarm when the gas pressure measured by the compound meter 5 reaches a predetermined control value.

  The spacer 9 insulates and supports the high-voltage conductor 1 at a substantially central position of the high-pressure gas container 7 and partitions the high-pressure gas container 7 into several spaces (regions). The O-ring 10 is for sealing (sealing) the connecting portion between the metal tanks 3 or the connecting portion via the spacer 9.

  As shown in FIG. 2, the adsorption device 1 includes a container 11 having one end opened, a lid 14 that closes the opening of the container 11, a moisture adsorbent 12 accommodated in the container 11, and a first gas passage. A valve gas passage 15 and a connection gas hole 18 as a second gas passage are provided.

  The moisture adsorbent 12 is, for example, synthetic zeolite and is accommodated in the container 11 in a state of being placed in a breathable bag 13. The lid 14 closes the opening of the surface facing the mounting surface of the container 11 to the piping boss 4. The lid 14 is fixed to the container 11 with screws or the like.

  A hole having the same diameter as the piping boss gas passage 17 provided in the piping boss 4, that is, a connecting gas hole 18 is provided on the contact surface of the container 11 with the piping boss 4. Insulating gas or dry air can be supplied and exhausted through the connection gas hole 18.

  A step portion 11a protruding to the inside is provided near the center of the wall surface in the container 11, and the moisture adsorbent 12 inserted from the opening of the container 11 is pressed by the step portion 11a, and the storage position is maintained and fixed. Is done.

  As a result, the moisture adsorbent 12 is accommodated on the side close to the lid 14, and the other space is a moisture adsorption chamber 1a which is a part of the supply / exhaust passage.

  The valve gas passage 15 is provided on the wall surface between the housing position of the moisture adsorbent 12 and the piping boss 4. A valve 8 is attached to the outside of the container 11 exiting the valve gas passage 15. By opening and closing the valve 8, insulating gas or dry air in the high-pressure gas container 7 is supplied and exhausted through the valve gas passage 15, the moisture adsorption chamber 1 a, and the piping boss gas passage 17. The valve gas passage 15 is provided so as to supply and exhaust gas in a direction orthogonal to the gas introduction direction of the pipe boss 4.

  That is, the adsorption device 1 has a moisture adsorption chamber 1a in which a moisture adsorbent 12 is accommodated, and has the shortest gas flow path from the high-pressure gas container 7 to the moisture adsorbent 12 via the pipe boss 4 (pipe boss gas passage 17). The moisture adsorption chamber 1a is configured in the immediate vicinity of the piping boss 4 so that

  In addition to the adsorption device 1 shown in FIG. 2, for example, as shown in FIG. 3, the adsorption device 1 may be provided with a plurality of valve gas passages 15 and 16 on the wall surface of the container 11.

Here, the relationship between the water | moisture-content adsorption | suction capability of the adsorption | suction apparatus 1 and the moisture content which permeates in the high pressure gas container 7 is demonstrated.
It is necessary to increase the amount of water that can be adsorbed by the adsorption device 1 than the amount of water that enters the high-pressure gas container 7 from the outside.

  For example, when the connection part between the flanges 3a of the metal tank 3 has a structure (seal structure) constituted by a groove and an O-ring 10 as shown in FIG. 4, moisture in the air permeates the part of the seal structure. It enters into the high-pressure gas container 7.

  The permeated water amount can be calculated from a calculation formula for the permeated water amount of the O-ring 10 and the permeated water amount is proportional to the seal length of the O-ring 10. The amount of water that can be adsorbed by the adsorption device 1 is proportional to the cross-sectional area of the pipe boss gas passage 17 and inversely proportional to its length.

  For this reason, the attachment quantity of the moisture adsorbent 12 is mainly determined by the seal length of the high-pressure gas container 7 (connection portion of the metal tank 3) to be sealed, the cross-sectional area of the pipe boss gas passage 17, the length thereof, and the like. .

  The amount of moisture that permeates (enters) into the high-pressure gas container 7 from the outside is determined by the following (Equation 1).

Permeated water content: Qt = D × h / b × T × ΔP × L (Formula 1)
Where D: moisture permeability, L: seal length, h: O-ring moisture permeability width, b: O-ring moisture permeability thickness, T: time, ΔP: water vapor pressure difference between inside and outside.

  From this (Equation 1), it is understood that when the elements other than the seal length are common, the permeated water amount Qt is determined by the seal length.

  The amount of water that can be adsorbed by the adsorption device 1 can be calculated by the following (Equation 2).

Adsorbed moisture amount: Qb = q × t = M × K × S × T (Formula 2)
However, q: flow rate, M: diffusion constant, S: cross-sectional area, t: temperature, T: time, K: concentration gradient. Here, it can be expressed as K = α × P / (273 + t) × (V1−V2) / d.

  Here, α: constant, P: pressure, V1: moisture content in tank, V2: moisture content in adsorption device, d: pipe length.

  From this (Equation 2), the adsorbed moisture amount Qb is determined by the cross-sectional area of the pipe boss gas passage 17 and its length.

  Therefore, when a plurality of piping bosses 4 are provided on the peripheral surface of the metal tank 3, a number of adsorption devices 1 whose adsorption moisture amount of the adsorption device 1 exceeds the permeated moisture amount that permeates the high-pressure gas container 7 are attached to the piping boss 4. Shall.

  Hereinafter, a gas replacement procedure for changing an existing gas circulation type gas-insulated switchgear to a sealed-off system, that is, a sealing work method will be described with reference to FIGS.

  As shown in FIG. 5, the gas-insulated switchgear of the gas circulation system includes a gas circulation mechanism 100 including an adsorption device 101, a gas circulation pipe 102, a circulation device 103, a compound meter 105, a switch 106, etc. It is connected to a valve 8 attached to the piping boss 4 of the container 7.

  When sealing work is performed on such an existing gas circulation type gas insulated switchgear, it is necessary to replace the high pressure gas container 7 with the atmospheric gas by replacing it with the internal insulating gas. If it is replaced with air containing moisture, the inner surface of the high-pressure gas container 7 absorbs moisture.

  Therefore, in this embodiment, first, the gas circulation mechanism 100 (broken line part) is removed from the existing gas circulation type gas-insulated switchgear, evacuated from the valve 8, and then dry air is sealed from the valve 8. The valve 8 is removed when a new adsorption device is installed.

  Specifically, in order to reduce moisture in the high-pressure gas container 7, a vacuuming device is connected to the valve 8 attached to the piping boss 4, and the insulating gas in the high-pressure gas container 7 is recovered by vacuuming. .

  Thereafter, a gas cylinder filled with an inert gas such as dry air or nitrogen gas whose moisture concentration is controlled to be sufficiently low is connected to the valve 8 of FIG. 6, and the inert gas is sealed in the high-pressure gas container 7 from the gas cylinder.

In general, while the moisture concentration in the atmosphere is on the order of%, the managed moisture concentration in the gas when operating the gas insulated switchgear is about 500 ppm, and the moisture concentration of each other is a difference of about 10 ² digits. There is.

  Therefore, the increase in the amount of moisture after the sealing work is suppressed by enclosing a gas (inert gas) having a low moisture concentration such as dry air or nitrogen gas controlled to several tens of ppm in the high-pressure gas container 7. Can do.

  After sealing the inert gas, the gas cylinder is removed from the valve 8 and the adsorption device 1 is attached to the piping boss 4 as shown in FIG. 7 within a predetermined time (for example, 30 minutes).

  Thereafter, a vacuuming device is connected to the valve 8 and vacuuming is performed to recover the inert gas in the high-pressure gas container 7.

  After collecting the inert gas, a gas cylinder filled with a new insulating gas is connected to the valve 8, and the insulating gas is injected into the high-pressure gas container 7 from the gas cylinder and the valve 8 is closed. Insulating gas is sealed in to complete a series of gas replacement procedures.

  FIG. 8 shows the results of a test operation of the gas insulated switchgear (see FIG. 7) subjected to the above gas replacement procedure. FIG. 8 is a diagram showing the transition of the amount of moisture when the adsorption device 1 is directly attached to the piping boss 4 and the verification test is performed, and the manner in which the moisture concentration in the high-pressure gas container 7 changes with the passage of time. It is shown.

  In carrying out the verification test, the amount of moisture that permeates through all the O-rings 10 of the high-pressure gas container 7 is calculated, and a sufficient amount of moisture adsorbent 12 that can be adsorbed with respect to the calculation result is added to the adsorption device 1. Enclosed (stored).

  In the transition curve of FIG. 8, the water concentration once rises immediately after sealing, but after balancing for about two months (the position of the broken line), the water content in the high-pressure gas container 7 gradually decreases and converges. It was confirmed to go.

  Thus, according to this embodiment, by attaching the adsorption device 1 provided with the moisture adsorption chamber 1a in the immediate vicinity of the piping boss 4 of the high-pressure gas container 7, the moisture concentration in the high-pressure gas container 7 can be reduced even if it is not a circulation system. It becomes possible to manage sufficiently low, and the circulation type moisture management mechanism can be shifted to sealing.

  Further, since the surface of the adsorbing device 1 facing the mounting surface to the pipe boss 4 is an opening, and the opening is closed by a lid 14 that can be opened and closed, the moisture adsorbent 12 can be easily stored and removed from the container 11 ( Exchange). As a result, the maintenance cost of the gas insulated switchgear can be kept low.

  Although the embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Adsorption apparatus, 1a ... Moisture adsorption chamber, 2 ... High voltage conductor, 3 ... Metal tank, 3a ... Flange, 4 ... Piping boss, 5 ... Compound meter, 6 ... Switch, 7 ... High pressure gas container, 8 ... Valve , 9 ... Spacer, 10 ... O-ring, 11 ... Container, 11a ... Step part, 12 ... Moisture absorbent, 13 ... Bag, 14 ... Lid, 15, 16 ... Gas passage for valve, 17 ... Pipe boss gas passage, 18 ... Gas hole for connection.

Claims (5)

A gas container in which a plurality of cylindrical members having flanges at the ends are connected by the flanges;
An air supply / exhaust port provided on the peripheral surface of the tubular member, for supplying and exhausting gas to and from the gas container;
An adsorbing device that is attached in the immediate vicinity of the air supply / exhaust port and has a moisture adsorption chamber containing a moisture adsorbent ;
The adsorption device is:
A container containing a moisture adsorbent in a part of the moisture adsorption chamber;
A first gas passage provided on a wall surface between the moisture adsorbent accommodating position of the container and the air supply / exhaust port, for sucking and exhausting gas in the container through the moisture adsorption chamber;
A second gas passage provided on a contact surface between the container and the intake / exhaust port and communicating the gas container with the moisture adsorption chamber;
A gas insulated switchgear comprising:   When a plurality of the air supply / exhaust ports are provided on the peripheral surface of the cylindrical member, one or a plurality of the adsorbing devices in which the amount of adsorbed moisture of the adsorbing device exceeds the amount of osmotic water penetrating the gas container are supplied and exhausted. The gas insulated switchgear according to claim 1 attached to a mouth.   2. The gas insulated switchgear according to claim 1, wherein the adsorption device has an opening at a surface facing an attachment surface to the air supply / exhaust port, and the opening is closed by a lid. Evacuating the air supply / exhaust port of the gas container to recover the insulating gas sealed in the gas container;
After recovering the insulating gas, sealing the inert gas whose moisture is controlled from the air supply / exhaust port to the gas container;
Attaching an adsorbing device for sealing to the air supply / exhaust port after enclosing the inert gas in the gas container;
Evacuating a gas passage provided in the adsorption device to recover the inert gas in the gas container;
A gas replacement method for a gas-insulated switchgear, comprising: collecting a new insulating gas from the gas passage to the gas container after recovering the inert gas. The gas replacement method for a gas insulated switchgear according to claim 4 , wherein dry air or nitrogen gas is used as the gas controlled to have a low moisture concentration.

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