JPS6043005A - Sulfur hexsfluoride gas substituting device of enclosed switch board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to an electrically insulating gas replacement device μ (-) enclosed in a closed switchboard, in particular sulfur hexafluoride gas (hereinafter referred to as SF
6 gas).

[Technical background of the invention and its problems] In recent years, efforts have been made to improve insulation properties by sealing SF6 gas inside closed switchboards, and to reduce the installation floor area by downsizing closed switchboards. The insulation properties of this SF6 gas vary depending on the concentration, pressure, and moisture content.
), and this management has become an important issue.

FIG. 1 is a single line diagram showing an example of conventional power receiving equipment, in which 1 is a power supply side bus bar, and a power supply side disconnecting section 2A connected to this power supply side bus bar 1 is connected to a breaker 4 via a converter 3. The other end of this cable ji4 is connected to the cable head 5 via the load-side disconnection section 2B.

Further, both sides of the circuit breaker 4 are provided with two Cs so that they can be grounded through a grounding/disconnecting section 6, and a load-side disconnecting section 2 is provided on each side.
A potential transformer 7 and a lightning arrester 8 are connected to the load side of B.

Next, FIG. 2 shows a closed switchboard 1 in which a Wake-type device not shown in FIG.
0, the SF6 gas is fed into the closed switchboard 10 from the valve 11A provided in the closed switchboard (1, below the panel 10) 1-, and the SF6 gas in the closed switchboard 10 is maintained at a predetermined concentration and pressure. When this happens, the valve 11A and the closing arrangement are connected. A valve 11B provided at the top of the panel 10 is closed.

Here, there are two methods for replacing SF6 gas into the closed switchboard 10.

(1) Vacuuming method This method is to first exhaust the air inside the closed switchboard 10 and then fill it with SF6 gas.
It has the feature of draining the moisture inside, and is the most commonly used method.

(2) Replacement method This method takes advantage of the fact that the specific gravity of SF6 gas is about five times that of air. SF6 gas is sent into the closed switchboard 10 from the valve 11A shown in FIG. This is a method of forcing air out of the valve 11B.

However, these two conventional methods p and + each have the following problems.

(1) Vacuum suction method As the pressure inside the closed switchboard 10 is reduced, external pressure due to the pressure difference between the inside and outside of the closed switchboard 10 is applied to the closed switchboard 10, so it is necessary to reduce the strength of the closed switchboard 10. It was necessary to increase the size of the inner wall and increase the thickness of the outer panel. Then, the idle switchboard 10
The weight of the product increases, making assembly, transportation, and installation difficult.

(2) Replacement method Replacement method The SF6 gas fed into the closed switchboard 1 () may be mixed with air due to turbulent flow in the partitions or storage equipment inside the closed switchboard 10. Because it will be
Until the SF6 gas in the closed switchboard 10 reaches a predetermined solubility, it is necessary to introduce SF6 scum from the outside and discharge the mixed gas diluted with air to the outside of the closed button arrangement stone board 10. The SF6 gas discharged during this time is wasted.

Also, if you want to eliminate the turbulence of the SF6 gas,
If the partitions in the closed switchboard 10 and the G distribution of the storage equipment are changed, the number of containers in the closed switchboard 10 will increase, and the installation floor space will become smaller.

Furthermore, in order to prevent the turbulent flow of the SF6 gas, 1-1, the flow rate of the SF6 gas injected into the closed ψi switchboard 10 is reduced, and the injection time becomes longer, so that mixing with the residual air (σ) progresses.

Furthermore, this replacement method requires a closed configuration. Since the moisture inside the board 10 cannot be removed, there are 97 cases in which the insulating properties of the SF6 gas after replacement deteriorate. ) [Object of the Invention] The present invention provides an advantageous method for eliminating the need to strengthen closed switchboards and
To provide an SF6 gas replacement device for a closed switchboard capable of replacing SF6 gas without emitting two SF6 gases.

[Summary of the invention] The present invention provides a method for replacing SF6 gas into a closed switchboard.
In addition to reusing the mixed gas with the second discharged air,
Detect the pressure, concentration, and moisture content of the SF6 gas inside the closed switchboard, and check the SF6 gas that was replaced inside the closed switchboard.
This is an SF6 gas replacement device with a closed switchboard that sets the pressure, concentration, and moisture of 6 gases in a predetermined order.

[Embodiments of the Invention] Hereinafter, an embodiment of the SF6 knobs replacement device for a closed switchboard according to the present invention will be described with reference to FIG.

In the figure, valves 11A and 1 are located at the bottom of the closed switchboard 10.
1C is provided, and a t1 valve 11B is installed at the top of the closed switchboard 10.
is provided, and a pressure gauge 12 is provided on the side.

In addition, the SF6 cass tank 1 is connected to the valve 11A via the valve 11D.
3 is connected, and when the valves 11A and 11D are opened, the SF6 gas in the SF6 gas tank 13 is sent into the closed switchboard 10, and the other end of the valve 11C is connected to the compressed air tank 14. When the valve 11C is opened, compressed air flows into the closed switchboard 10 from 17C.

Further, an SF6 gas concentration meter 15 is installed at the other end of the valve 11B.
A moisture meter 16 is connected to the other end of this SF6 gas thermometer 15, and the other end of this moisture meter 16 is connected to a compressor 18 via a dust filter 17. The SF6 gas compressed by this compressor 18 is compressed by the compressor 1
After the oil mixed in by the compressor 18 is removed by the oil filter 19 connected to the other end of the oil filter 1
It is sent to a liquefier 20 connected to the other end of 9 and liquefied, where the mixed desired air and water are separated and discharged to the outside from a valve (not shown).

On the other hand, the liquefied SF6 gas is released from the valve 11E, vaporized, and sent to the dehumidifying filter 21, where it is further removed with C, and then circulated back into the closed switchboard 10 via the check valve 22 and the valve 11A. It is becoming more and more like this.

Further, a pipe branched from the oil filter 19 and the middle 11 part of the liquefier 20 is connected to a pressure reducing valve 23 (C) via a valve 11F, and the other end of this pressure reducing valve 23 is connected to the valve 11F and the drying filter 21. Glued to the middle part of J and N.

In addition, in the explanation of FIG. 3 above, the S separated in the liquefier 20
In the explanation 17, it is assumed that the air in the F6 gas is released to the outside, but it may also be sent to the compressed air tank 14 through the C-valve 11G, as shown by the dotted line in the figure, or it may be separated in the liquefier 20. SF6 gas is also not shown by the dotted line in the figure, but is directly supplied via valve 11H.
A pipe line for sending to the F6 gas tank 13 may be added.

Also, in the same figure, the compressed air tank 14 may be replaced by any other air source in the field for displacing SF6 gas into the closed switchboard 10, and furthermore, in FIG. A drying filter may be provided.

[Operation of the Invention] Next, a method of replacing SF6 gas using the SF6 gas replacement device for a closed switchboard configured as described above will be described.

First, in FIG. 3, with valves 11C, 11D, and 11F closed, valves 11A and 11B are opened, and after turning on the compressor 13, 11D is opened to remove the S in the SF6 gas tank 13.
F6 gas is sent into the closed switchboard 10 and the valve 11E is opened.

Then, the SF6 gas that has entered the closed switchboard 10 mixes with the remaining air, and is then injected into the closed switchboard 10 (into the SF6 gas that has been sent in through the valve 11B, and passes through the SF6 gas concentration meter 15, moisture meter 16, dust Filter 17, compressor 18
, enters the liquefier 20 through the oil filter 19, where it is separated from air and moisture, and then passes through the valve 11E and the drying filter 2.
1. It is sent into the closed switchboard 10 again through the check valve 22 and the box 11A.

Thereafter, this process is repeated I7 to increase the concentration of the mixed gas inside the closed switchboard 10 and remove moisture inside the closed switchboard 10, so that the pressure gauge 12, SF6 gas concentration meter 15, and moisture meter 16 indicate the is within a predetermined range, the valve 11A, 1
1B and 11D are closed and the compressor 18 is turned off. If the compression meter 12, SF6 gas concentration meter 15 and moisture meter 16
If any one or two conditions of q) are not satisfied, operate as shown in the table below.

In the same table, the ○ mark in the gas status column indicates pressure gauge 12, SF
The indicated values of the six gas concentration meter 15 and the moisture meter 16 are within the required range, respectively, and the ↑ mark indicates that it exceeds the predetermined range, and the ↓ mark indicates that it falls below the predetermined range.

Next, the pressure, concentration, and range of moisture content of SF6 gas set in the SF6 gas replacement device for a closed switchboard according to the present invention will be explained.

(1) Output of SF6 gas FIG. 4 shows the results of an experiment showing the characteristics of the pressure and flash voltage of SF6 gas.

In the same figure, the horizontal axis is the gauge pressure of SF6 gas, and P1=
0, P2=0.5, and the vertical axis is the pressure of SF6 gas 1-
The charging voltage characteristics are shown below. As shown in the figure, the withstand voltage is SF
Since the pressure of SF6 gas shows one of the maximum values near 0.25 kgf/cm2 in gauge pressure, the pressure setting range for SF6 gas in the present invention is from 0 to 0.51 kgf/cm2 in gauge pressure.

(2) Concentration of SF6 gas FIG. 5 does not show the characteristics of the concentration of SF6 gas and the flash voltage, but shows the results of an experiment.

In the figure, the horizontal axis represents the concentration of SF6 gas mixed with air, and the vertical axis represents the charging voltage characteristics depending on the concentration of SF6 gas. Figure C - As shown, the withstand voltage is 90% when the SF6 gas concentration is
It shows maximum + near %L, 90% So, it gradually decreases below 90%
If the concentration exceeds 75%, the concentration decreases rapidly, so the concentration setting range of SF6 gas in the present invention is set from 75% to 95%.

[Effects of the Invention] As described above, the SF6 gas replacement device for a closed switchboard according to the present invention has the following effects.

(1) Before sending SF6 waste into the closed switchboard.

Since there is no need to create a vacuum inside the closed switchboard, there is no need to increase the enclosure of the closed switchboard.

(2) Low-intensity SF6 gas mixed with air in a closed switchboard is recovered and reused, so there is no waste.

(3) Since moisture and dust remaining in the closed switchboard can be removed, the electrical characteristics of SF6 gas can be guaranteed.

[Brief explanation of drawings]

Fig. 1 is a single line diagram showing an example of conventional power receiving equipment, and Fig. 2 is a conventional closed wiring diagram 41 filled with SF6 gas.
y side view, Figure 3, 1, SF6 of the closed power distribution of the present invention
FIG. 4 is a circuit diagram showing one embodiment of the replacement device, and FIG.
The figure is a characteristic diagram obtained experimentally of the relationship between the concentration of SF6 gas and the flashover voltage. 10...Closed switchboard 11A, 11B, 11c, 11
D...Valve 12...Pressure gauge 13...SF6 gas tank 14...Compressed air tank 15...SF6 gas concentration meter 16...Moisture meter 18...Compressor

Claims (1)

[Claims] A gas replacement device for sealing sulfur hexafluoride gas in a closed switchboard, comprising: a device for supplying the sulfur hexafluoride gas into the closed switchboard; a device for supplying air into the closed switchboard; and the closed switchboard. a pressure measuring device for the sulfur hexafluoride gas replaced in the closed switchboard; a pressure measuring device for the sulfur hexafluoride gas replaced in the closed switchboard; and a pressure measuring device for the sulfur hexafluoride gas replaced in the closed switchboard; ) a moisture detection device, and a device for discharging and compressing the sulfur hexafluoride gas substituted in the closed distribution box, separating the contained air, and circulating it back into the closed distribution box. Sulfur hexafluoride gas replacement device for closed switchboard.