DE3122886C2 - Process for filling and emptying housings for gas-insulated electrical devices and systems - Google Patents

Abstract

The invention relates to a method for filling and / or emptying housings for gas-insulated electrical devices and systems using the so-called displacement method. The aim is to economically recover as high a proportion of insulating gas as possible from the gas mixture displaced from the housing. For this purpose, the displaced gas mixture is compressed and fed to a cooled separation container. This has a gas discharge valve at its highest point and a controllable liquid discharge valve at its lowest point. The valves are automatically actuated in the separating tank according to the specified operating conditions (pressure, temperature and liquid level).

Description

3 4

Features of claim 1 solved ren lead to solid body formation and thus to operational

In the following, the invention is based on an example of malfunctions; higher pressures increase the system costs

explained in more detail disproportionate in comparison to the increase in

That from a housing 1 to be filled with a switching SFe yield.

position (Fig. 1) displaced air-insulating gas mixture should 5 The absolute insulating gas losses of the filling and emptying over one or more compressors 2 under high voltage process of a housing for high-voltage pressure to a cooled separation container 3 are fed or plants are directly dependent from the the den. This separating container, which is advantageously designed as a cylindrical separating container for the air or quantity of inert gas supplied, and with its axis perpendicular, is therefore advantageous not to use the entire gas mixture displaced from the seat above a gas discharge valve 4 and below a liquid housing to the separating container zuzukeitsablaßventil 5. In addition, he has one measurement lead-in, but rather a point in time, which corresponds to the direction 6, 7 for pressure and temperature. As soon as the smallest possible loss of insulating gas results
Isoliergaspartialdruck in this container that the F i g. 2 shows the quantitative curve of the _{vapor pressure of the isocentration corresponding to the SF 6} container temperature at the outlet opening of a switching field gelling gas, a liquid sump forms in the lower container part 15 when it is filled using the displacement method. The area Fi above the curve corresponds to the volume of air escaping from the separating tank 3 liquefies, while the gas portion liquefies, while the air portion increased a pressure area F2 below the escaping SF ₆ volume in the tank causes gives The emptying process occurs if the items are mixed up

Via a measuring device 8 of a liquid level connection 20 analogously, where r \ is the insulating gas volume

indicator, which preferably uses a switching contact men and Fi to stiffen the air volume. Do you do that

is equipped, can with a sufficient liquefied iso gas mixture too early (before time t _opt ) the

If the signal for draining the liquid is added to the separating tank, this results in increased SF ₆ losses

through the lower valve into a storage container 9 or when releasing the air from the container. Do you run it

being given a bottle, or draining auto-25 too late (after the top time), those are right in

take place automatically. The draining of the liquid must be too high to avoid the _{SF 6 losses escaping from the atmosphere.} Of the

take place slowly so that the pressure drop in the tank can be calculated optimally

does not lead to spontaneous boiling. In addition, it may be right. He is then reached when> the insulating gas content

The liquid does not fall below a minimum level in order to equal the quotient of the partial pressure of the exhaust gas

a breakthrough of the gas in the storage container to 30 insulating gas and total pressure in the separation container (P- _IS J

avoid. For this purpose, a second, P _n ) may be required for the opening of the gas discharge valve.

The liquid level indicator attached below is the operating conditions of the separating tank.

of advantage, if it falls below the drain valve 5 It is therefore useful during a filling or

is closed. Emptying process that emerges from the housing

As a rule, however, a liquid level indicator 35 gas is to be monitored with regard to its insulating gas content

with switching contact is sufficient, which as a result of its and via valves, the separating container or the atmos-

Switching hysteresis in each case remove small amounts of liquid - supply sphere, depending on whether the insulating gas content

lets is greater or less than PaolPmt

So that the minimum liquid level is sufficiently high. The described filling and emptying procedure

is without a disproportionately large liquid 40 of housings for gas-insulated electrical equipment and

must remain in the separating tank 3 at all times, systems with low insulating gas loss are fundamentally

this can advantageously be used as a vertical cylinder when the insulating gas is opposite one

the running air has a significantly low vapor pressure, which is

The discharge of the gas from the separation vessel 3 beneath SF6 also takes place for halogenated coals, for example through the upper valve 4. Since the gas insulating gas 45 applies to hydrogen, which are interesting as insulating gases.

jit · 1, u »n · ^Pil ° 1 uD η. · If the contact between acid and

and air in a ratio of 7 ^ 3 ^ (wöbe. P _iso = particulate _{matter and any spa products of the insulating gas}

aldruck of lsoliergases, P, _O, = total pressure) does not mean is desired, instead of air and nitrogen, or

contains, it is only advisable to use a different inert gas. as well

if the greatest possible total pressure 50 can be let the housing before filling with a protective gas

in the housing 1 designated as aucii container in which be filled, which is displaced by the insulating gas,

the lowest possible container temperature. The displacement can be

However, under these conditions, the insulating gas loss is at its lowest if the density difference

sten. Due to the series connection of a pressure gas and one between insulating gas and displacement gas is very large.

This process 55

Easily automate so that a continuous flow of 1 sheet of drawings

drive is possible.

The new process makes it possible to economically produce the insulating gas from gas mixtures with a large proportion of air to be deposited. 60

If SFb is used as an insulating gas, each result
according to the amount of in the production plant or on the
SFö-air mixture arising on the construction site, economical Arbeitsspuiikte for the separating tank 3 in one
Temperature range between -20 ° C and -50 ⁰ C at 65
Pressures from 20 to 6 & bar.

Higher temperatures and lower pressures result in an insufficient SFv yield, lower temperature

Claims (4)

26 33 355 as known. Claims: From DE-OS 24 59 998 a device for cleaning insulating gas is known. 1. Process for filling and emptying cleaned gas sucked off, compressed and cooled in order to convert the housing for gas-insulated electrical devices and anIa-5 insulating gas into the liquid phase. Remaining, which is operationally filled with a gas (preferably empty, undesired gases above the liquid SFe), the vapor pressure of which is clearly low, is blown out via a pressure relief valve,
Ger is than that of air and soft to be filled. A method for filling high-voltage lines is known from DE-PS 20 48 994 by means of a gas connection which is located in the housing and which is exiting at the housing outlet Gas mixture of SF6 gas the gas present in the housing (air N ₂ or and air captured and the insulating gas for another protective gas) by a second, preferential use, for example in a centrifugal reference above, displaced gas connection, and drive »out. which are emptied by the insulating gas being displaced in the opposite direction from the essay »Use of sulfur hexafluoride by inflowing air, 15 and its recovery from a gas mixture« er-N2 or another protective gas, with appeared in »Reports from Technology and Science a device, which from the displaced gas with- 38/1976 "from the Linde company, a method is known by means of pressure and cooling liquefied insulating gas to which SF ₆ is recovered by cooling to temperatures. characterized, semlich below the triple point as a solid from eid that the displaced gas is separated under high pressure from a 20 nm SF6-N2 mixture. The stick-cooled separating container (3) is supplied, which material above the solid is liquefied or in a liquid drain valve (5) again heated by vacuum pumps at its highest point by vacuum pumps the gaseous addition as well as at least one measuring device (6,7,8) each ) the low residual amount of SF6 in the exhaust gas of less of the separating container (3) opens automatically if it is more than 1%. most opposite. given Drude is exceeded that the 30 from DE-AS 22 29 413 is a collection and storage Enclosures (1) displace *? Gas with regard to its iso-tank for SF6 with a device for air removal The gas content is monitored and only then known to the separating train. It consists of a pressure vessel which container (3) is supplied when ^ the Isoliergasanchem liquid SF6 is supplied and at which part is at least as large as the quotient from, after reaching the critical pressure, an above Partial pressure of the insulating gas and total pressure in the 35 arranged vent valve is opened. These conditions Separating container (3) for the opening of the gas outlet is only possible with a negligibly small proportion of air. Let valve (4) specified operating conditions. fillable. So that is also insignificant when using the air 2. Procedure for filling and emptying ge when opening the vent valve an uncontrolled housing for electrical devices and systems after an available amount of SF ₆ escapes claim!, characterized in that 40 metal- _{encapsulated SF 6} -insulated switchgear is drawn- the use of SF ₆ as an insulating gas, which is necessary for the automatic release compared to conventional air-insulated Opening of the gas discharge valve (4) predetermined limits due to the much smaller construction and un- temperature is between - 20 ⁰ C and - 50 ⁰ C and sensitivity to atmospheric the specified limit pressure between 20 bar and the operating conditions of the operating site. The higher ones 50 bar. 45 Costs of this construction method have so far largely prevented 3. Process for filling and emptying of the area a transfer of these technical advantages Housing for gas-insulated electrical devices and AnIa voltage levels below 110 kV. With the switchgear gen according to one of claims 1 or 2, characterized in the conception according to DE-OS 26 59 038 is indicated on an evage, that the liquid drain valve (5) dispenses kubaren housing and an air portion in the is opened when the liquid level in the insulating gas of 5% or more is permissible. So that is now Separation container (3) the corresponding measuring device also the economic use of metal-encapsulated device (8) is exceeded and is closed if SF6-insulated switchgear at a lower nominal voltage Liquid level the measuring device (8) or voltages possible. if necessary, a second, deeper-lying liquid keitsmeßeinrichtung falls below 55 emptying method according to the displacement principle 4. The method for filling and emptying the housing has the disadvantage of considerable SF ₆ losses compared to the method with evacuable anaerials for gas-insulated electrical devices and systems, which are up to 50% of the housing volume according to one of claims 1 to 3 can be and therefore shows that as a separating container (3), a cylindrical container with a correspondingly high environmental impact and cost with a vertically positioned Rota- 60 cause. tion axis is used. The object of the present invention was therefore that insulation gas loss occurring during filling and emptying ste under economic and production engineering To restrict aspects to a minimum, in which the greatest possible amount of insulating gas in one The invention relates to a process according to continuous processes for reuse the features of the preamble of claim 1 is recovered. Such a procedure is inter alia. from DE-PS The given task is identified by the