JPS6074910A - Method of managing purity of insulating gas - 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 a method for controlling the purity of an insulating gas, and more specifically, the present invention relates to a method for controlling the purity of an insulating gas. This invention relates to a method for controlling the purity of insulating gas when storing the gas in a storage tank and reusing it.

[Prior art]

A conventional management method of this type will be described with reference to FIG. 1 in the case where SF6 gas is used as the insulating gas. Figure 1 shows how to recover SF6 gas from electrical equipment and
Showing a system for refilling electrical equipment with F6 gas, SF6
The gas is stored in a storage tank 9 via a compressor 6. At this time, valve 3° wide, 51g open, pulp/θ
,/,2. /g is closed. Oil filter is liquefied science fiction
This is provided to remove oil from the compressor B that gets mixed into the compressor. The SF6 gas pressure inside the electrical equipment is monitored by the compound meter 2, but when this pressure drops to near atmospheric pressure, the gas recovery speed of the compressor B also begins to slow down, prolonging the recovery time. At this time, operate the vacuum pump //, close the valves /3./g, /j-, / O, and close the valves 10.
/, 1 is opened, the SF6 gas at atmospheric pressure or lower is efficiently guided to the pressure m machine 4 by the vacuum pump /l, so that the gas recovery time is shortened.

・As liquefied SF6 is stored in the storage tank lid, is the liquid level? / rises. This liquid level q/&i is monitored by a liquid level gauge (not shown), and the liquefied 5F69.2 is in the storage tank 90g0~? It is designed to stop the operation of compressor B when the volume reaches 0. The gas space 93 above the liquid level 9/ is filled with SF6 gas in a vapor phase corresponding to the saturated vapor pressure of the liquid temperature at that time.

Now, when the repair and inspection of the electrical equipment is completed and it is time to fill it with SF6 gas, the air inside the electrical equipment is replaced by the vacuum pump.
It is exhausted by l. At this time, valve 3.10. /3 is open, the valve is closed, and /2 is closed. When the degree of vacuum inside the electrical equipment/equipment reaches a predetermined value, the valve/θ is closed, and then the operation of the vacuum pump// is stopped, and then the storage tank is closed. SF6 gas is then filled into electrical equipment. This operation opens the valve /lI, /6.4', closes the pulp left, and t.
This is done by adjusting the pressure reducing valve. Gas space above liquid level in storage tank? 3 is filled with gaseous SF6, but strictly speaking, a small amount of air is mixed in.

This air is compressed 4 times when the gas is recovered from inside the electrical equipment.
It is mixed together with SF 6 via DA.

Now, the degree of vacuum before the first gas filling of the electrical equipment / T
orr, and if the internal volume is /θd, then air of /313 is recovered into the storage tank 9 together with the filled SF6, and this fills the gas space q3 above the liquid level.
It will be mixed in. If the volume above the liquid level in the storage tank lid is 1006 and the saturated vapor pressure of 8F6 is 2S atm, the air concentration in the gas space 93 will be approximately θ3. With each repetition, the air concentration in the gas space 93 above the liquid level increases, so we had to reject the SF6 gas that was being filled into the electrical equipment from this storage tank lid at a certain stage.For this reason, In extreme cases, it may be necessary to dispose of all the gas mixed with air in the storage tank lid, evacuate it, and then use it again for gas recovery, which has the disadvantage of being extremely uneconomical. Ta.

[Summary of the invention]

This invention provides a separate valve at the bottom of the storage tank, and when the air concentration above the liquid surface becomes large enough to not be ignored, an operation is performed to take out the pure SF'6 liquid or gas from this valve. The present invention provides a purification gas purity control method that eliminates the drawbacks of the conventional method by repeating the above steps until the gas concentration reaches an allowable control value in the purity control means provided.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in terms of the second section. In the figure, the same reference numerals indicate the same parts as in FIG. In the figure, a gas space 93 at the liquid level 9/ of the storage tank 9 storing the recovered SF6 is filled with a mixture of SF6 gas and air. If SF6 gas is filled in this state via the upper filling valve/g, the air in the 8F6, especially oxygen, will reach a concentration that becomes a problem (for example, 07
%), storage tank? The pure liquid SF6 is transferred from the bulb light provided at the bottom of the tank to another second storage tank 90 via the bulb deO5. At this time, first storage tank in advance? 8F6 liquid on the side at 7-2℃
Only the heater? Preheat by gas space? If the pressure in 3 is increased, the liquid SF6 can be transferred quickly. A gas purity control means 9g, such as an oxygen concentration meter, is connected via a valve q& and a pressure reducing valve 97 branching off from the valve wire. While only pure liquid SF6 is being transferred from the first storage tank lid, the oxygen concentration meter is 9 g.
indicates zero, but when the air-fuel mixture in the gas space q3 above the liquid level begins to be transferred, the oxygen concentration meter qt begins to swing. When this runout exceeds the allowable value, the palbuta 5. ? θS
′? :The closure means that high purity liquid 8F6q02 and SF6 gas 90.3 are stored in the first storage tank 9θ, while only the air-fuel mixture and a very small amount of liquid SF6 are stored in the first storage tank. remain. Therefore, the first storage tank in this state? By exhausting the gas inside, it becomes possible to economically separate and remove the mixed air. After most of the high-purity SF6 is transferred to the No. 1 storage tank θ, the valve q//1. Electrical equipment can now be filled with pure SF6 gas via q/b and pressure reducing valve/S.

FIG. 2 also shows a system for directly filling electrical equipment with gas from a valve 99 branched from the pressure reducing valve 97. In this case, there is no need to use the separately placed storage tank 90. In that case, the operation of closing the pallet valve j when the indication on the oxygen concentration side 9g exceeds the permissible value is the same.

In the above embodiment, the valve? S was manually closed when the indication from the purity control means 9g exceeded the allowable value, but this can be done automatically by using the control circuit /θθ. In this case, the valve? Solenoid valve as S! By applying 4, the self-J operation becomes possible.

Further, in the above embodiment, the case of air entrainment due to recovery of SF6 gas is explained in detail, but it is equally effective for purity control when air is included during recovery of other fluorine-based insulating media.

〔Effect of the invention〕

As described above, this invention improves the reliability of gas-insulated electrical equipment because only pure insulating gas can be reused in an atmosphere where an air mixture exists above the liquid surface of the storage tank from which the gas has been recovered. At the same time, it has the effect of improving the economic efficiency of gas reuse.

[Brief explanation of the drawing]

FIG. 1 is an arrangement diagram for explaining a conventional method, and FIG. Ω is an arrangement diagram for explaining an embodiment of the present invention. l...Electrical equipment, 6...Compressor, g,/g. / Otsu, 93. del,,99.9O5,97g,9/6
··valve,? ...First storage tank, 15.9
? , 973...pressure reducing valve, riO...d storage tank, qg...oxygen concentration meter (purity control means), /θO
...Control circuit. In each figure, the same reference numerals indicate the same or corresponding 515 minutes. Agent Masu Oiwa Yuo 1

Claims (1)

[Scope of Claims] (1) Liquefied insulating gas recovered from electrical equipment by a compressor is stored in a first storage tank provided with a valve at the bottom, and a purity control means branched from and connected to the valve is stored in a first storage tank provided with a valve at the bottom. A method for controlling the purity of an insulating gas, characterized in that the purity of the liquefied insulating gas is monitored, and the high-purity insulating gas is transferred to either the electrical equipment or a second storage tank. (21g, the insulating gas purity control method according to claim 1, wherein the insulating gas transferred to the storage tank 2 is a liquefied insulating gas. (3) High purity according to the set value of the purity control means. A method for controlling the purity of an insulating gas according to claim 7, in which a control circuit automatically opens and closes a valve for transferring an insulating gas. A method for controlling the purity of an insulating gas. (51 Claim 1 in which the insulating gas is SF6 gas
Purity control method of insulating gas described in section. (B) The method for controlling the purity of an insulating gas according to claim 7, wherein the insulating gas is a fluorine-based insulating gas.