ES2345547T3 - MODULAR UNIT FOR ACCOMMODATION OF ABSORBING ELEMENTS FOR A DISTRIBUTION INSTALLATION. - Google Patents

Abstract

The module has the hot gas directed to at least one flow path containing at least one monolithic ceramic absorber element (10,10',10'') packed into a flow chamber (40) for the hot gas and provided with channels (11) for passage of the hot gas having a cross-section of between 2 and 10 mm and extending in the main flow direction.

Description

Modular unit for element housing absorbers for a distribution installation.

The invention relates to a modular unit for the accommodation of at least one element for absorption or damping of hot exhaust gases caused by an arc electrical in high and medium electrical functional units voltage, particularly in high distribution facilities or medium voltage.

A modular unit with the characteristics of preamble of claim 1 is known from the document DE-A-196 46 547.

By letter DE 196 45 304 C2 has been given to know a cartridge as a damping element, which is located at end of a pressure relief channel of an installation of medium voltage distribution that is otherwise encapsulated. The damping elements located in the cartridge are baffles metallic that are fixed in the form of angular plates bent in the route of the exhaust gases.

Another modular unit is known by the document DE 198 58 952 C1. In this modular unit a tour is present defined output for hot gases being formed there a chamber filled up to 70% of its volume with bodies loose dampers, preferably spherical. The shock absorbers are made of plastic and are raised in whirlwind by the gas flow, whereby the gas cools, it deionizes and brakes.

The enclosures for the facilities of distribution are often located in places where they can access people to pressure relief zones. Due to rigorous requirements to be met by facilities electric can only be used in a limited way known buffer installations.

As the electrical power of the electrical installations, such as power switches, busbar cells, power converters, transformers (hereinafter referred to as general as functional units) etc., the damping installations known can only be used in a limited way. For example when measuring currents intensities arise during measurement duration of ≥ 25 kA for 1 second, the bodies plastic dampers or metal baffles barely They can already achieve a protective effect. Due to the action of parasitic electric arc can be melted and / or plucked from its anchors so that the damping elements can exit to the outside through the orifice of the pressure discharge duct, Representing another danger.

The objective of the invention is to propose a modular unit for housing at least one element intended for the absorption or damping of hot gases from escape caused mainly by a parasitic electric arc that occurs in a medium voltage functional unit, which offers a greater protection against hot exhaust gases.

In general, it will be used here and in successive the concept of functional unity (regardless of these are installations with air or gas insulation), representative of:

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a switching cell or several switching cells,

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one or various distribution facilities (building blocks of distribution),

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one or several watertight enclosures in the switching cells or blocks of switching facilities,

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practicable and non-practicable enclosures of switching facilities and stations as well as enclosures watertight in these.

The solution of the problem is described in the characteristics of the main claim.

Other advantageous embodiments are formulated in the dependent claims.

The advantage offered by the modular unit is in which no moving parts are used, neither plastics nor metals that during high pressures and high temperatures they can become destroyed or decompose.

Another advantage of the invention is that in the case of a parasitic electric arc greatly reduces the pressure in the distribution installation, in the cells of switching and in the enclosure surrounding the installation.

Through the use of industrial ceramics of high quality robust material is used that without the use of moving parts offers effective protection against hot gases exhaust and that is also suitable for letting out the air that It has been heated in the appliance with a cooling effect.

The advantages of the proposed object are the following: Compared to an electric functional unit, in particular a distribution installation without arc absorber electrical parasite, the object of the invention can reduce the pressure that in a case of parasitic electric arc arises in the distribution facility enclosure, improve cooling of the exhaust air that has been heated by the heat of the current, improve protection against the effects of the breakdown in the building people and technical teams and contribute to a most effective use of space possibilities.

The modular unit can also be used to the case of subsequent equipment with arc absorbers Electrical parasite in order to improve pressure conditions in the case of the parasitic electric arc.

To cool the hot gases in the case of a parasitic electric arc caused by an internal failure in a functional unit ceramic absorber elements are used (honeycomb elements). The materials to consider are porcelain, Al_ {2} O_ {3}, ceramic - SiC, saponite and other materials also used as heat exchange ceramics.

The modular unit can be used in various embodiments of functional units, for example with switching cells and distribution facilities isolated by air as well as switching cells and distribution facilities isolated by gas, in compact stations or in enclosures of accessible and non-accessible distribution facilities and in switching stations Here they can be equipped with the unit functional switching facilities, partial areas of stations, station doors, enclosure passages and holes  of exit of enclosures. Hereafter used uniformly the concept of "functional unit", which however does not it means that the use of the modular unit should only be intended for a single functional unit or a cell of distribution. The concept of functional unity is about also representatively convey that the modular unit is Usable for a waterproof enclosure, for an installation enclosure distribution or for the entire installation of distribution with several switching cells, and that is adaptable in accordance with the respective circumstances.

The positioning of the modular unit is different according to the functional unit. Gas conduction it can take place in different directions or going to different enclosures (sealed enclosure of a distribution cell, conduit of pressure discharge, double bottom zone, cable duct, basement of cables). The determinant for the choice of position and the Gas conduction are the respective technical possibilities which offers a functional unit to achieve maximum security for people and unit pressure resistance functional. The way of building the modular unit that is necessary for the parasitic arc absorber adjusts to the respective use in a functional unit.

The ceramic absorber elements are fixed by fasteners. Such fasteners may be for example: at least one clamping plate in the form of lattice or perforated, staples or fastening bands surrounding the perimeter of the absorber elements. Fasteners they can be composed of individual pieces and be fixed in the absorber housing, or they can also be an integral part of the absorber housing.

The number of absorber elements per layer varies, adapted to the dimensions of the modular unit to prevent that in the case of a parasitic electric arc the totality is broken of the absorber surface. The installation of the elements absorbers in the frame should allow the corresponding expansion thermal of the entire arrangement during heating (caused by the heat of the current or in a case of electric arc parasite), thus contributing to the absorption of forces thermal by the modular unit.

The essential element of the modular unit is by At least one monolithic ceramic absorber body. The channels of the absorber elements are formed in such a way that thanks to its large length or small diameter is obtained IP protection (protection against contact, keep tools away, safety against punching). As an alternative there may be in additionally absorbing elements or in the case of channels of large diameter a perforated cover over the elements absorbers so that with that cover is guaranteed the IP protection

Perforated sheets or metal plates expanded, optionally arranged below and / or above  absorbent elements, may preferably be made of such that they contribute to optimize the decrease in pressure and allow free passage to the gas outlet through the structure of honeycomb channels. An expanded metal located by below in the direction of gas flow (according to DIN 791) can serve as a standing point for an electric arc, and contribute from this way to shorten the electric arc in the waterproof zone. Simultaneously this expanded metal can contribute, thanks to the shape of your meshes, to control the flow and with it the reduction of pressure. Typical dimensions of an expanded metal can be for example the following: 6 mm mesh length; width of 3.4 mm mesh; bridge width 1.25 mm; metal thickness expanded 2 to 3 mm; 0.5 mm bridge thickness.

Clamping plates should have holes relatively large The important thing is that by clamping you get enough mechanical strength to support the structure absorbent. The fasteners of metal type (metal expanded or clamping plate) should not be painted in order to prevent the paint from burning and an additional load due to gases harmful to health.

The complete modular unit for the absorber of the parasitic electric arc can be mounted screwed or riveted, the modular unit should be mounted preferably by means of a flange (preferably directly in the frame of the modular unit) to a functional unit. The mount point comes determined by the field of use of the functional unit.

In the case of switching cells e distribution facilities isolated by gas or isolated by air, the modular unit can be used in the manner also described in special pressure relief channels. By combining of absorber elements of different numbers of channels to equal area of passage, in the placement arranged one after another (for example vertically one over another) and driving corresponding gas rectilinear is optimized at the same time the decrease in pressure in the channels of the absorbers and the hot gas cooling. For this, the lower absorber elements with a smaller number of channels per item, and those arranged immediately above with a multiple of those. For this, the wall thickness of the channels in such a way that a passage area is available substantially the same for the hot gases that pass through, and lower channels with greater wall thickness can absorb more heat.

In the distribution facilities and cells of gas insulated switching you have the possibility to perform an arrangement of the absorber elements in several steps, positioning the modular unit directly behind the bursting disk of the distribution facility or part of switching cell isolated by gas and / or on the back side or in a pressure relief channel.

The pressure reduction is adjusted by corresponding dimensioning of the absorber elements with relation to the number of channels, the area of the channels, the thickness of Channel wall, conditioned cooling surface for this and the free passage area available for the departure of gases The geometry of the ceramic absorber elements, their honeycomb structure and the area of vertical channels are the ones that determine the resistance to the passage of gas in a case of parasitic electric arc The channels of the absorber elements They are located essentially in the direction of flow exit. Due to the rectilinear flow of gases, sediments of particles that in case of a different arrangement can give result in undesirable pressure increases in the unit functional in a case of parasitic electric arc.

The height and strength of the elements ceramic absorbers are sized in such a way that for the maximum possible pressure the structure of the channels shaped Honeycomb elements do not suffer any damage, and despite this a maximum geometric surface is available for cooling hot gases. Cases may appear of failure in which the absorber material also suffers damage. For that reason it is important in the design and choice of material that the destroyed material of the absorbers if possible does not I can go outside. One possible measure may be that the thickness of an absorber material made in one piece is choose so large that the parasitic electric arc can only destroy a lower layer and be preserved without destroying a layer higher. Another measure may consist of several elements absorbers are placed on top of each other forming layers. The stratification can be done based on materials in which the resistance against the electric arc attack decreases (in the direction of gas flow).

The honeycomb structure of the element ceramic absorber has a different configuration according to the respective application case. So for example an element absorber with a length of 150 mm, a width of 150 mm and a 300 mm height can have up to 3600 (60 x 60) channels vertical, whose holes in the channels have a dimension of a few millimeters (eg within a range between 2 and 10 mm). The length of the channels in the honeycomb body is therefore of 300 mm The free open surface for the passage of gases is in the example cited above 60% of the floor area of the absorber element. The structure of the channels is chosen with the lowest possible wall thickness, that is about 0.5 to 0.9 mm, so that a very high heat absorption is ensured fast in the case of a short duration of the electric arc.

Especially in switching cells or high power class distribution facilities are they produce heat losses from the current (during the normal regime, without parasitic electric arcs). The disposition described offers a reduced resistance to flow for the output of the hot air from the functional unit through the channels of the absorber element and therefore is also suitable for evacuating The heat due to the current.

The ceramic absorber elements present compared to other materials the advantage of presenting a very high resistance to temperature changes. The same time, a very small average linear expansion coefficient of approx. 2.2 x 10 -6 to 6.5 x 10 -6 K-1 a maximum positive coupling with maximum resistance to temperature, with almost no combustion protection surface (such as zinc on steel). The elements ceramic absorbers are resistant against influences corrosive An open porosity of approx. 8 to 25% facilitates formation of whirlpools of the flow of gases in the channels of the absorber element. A porous material in the channels should be therefore prefer a pore free material.

The invention is explained in greater detail. using the drawings. These show in particular:

Fig. 1 schematic drawing of a modular unit open to see the absorber elements,

Fig. 2 a stratified unit structure modular, and in

Fig. 3 to Fig. 7, different positions of the modular unit in different functional units.

The following are represented in Fig. modular unit components:

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first clamping plate 12 below, with a lattice of holes 16, screwed or riveted in the housing of absorber 40,

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first lower perforated plate 14 (expanded metal; optional),

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three 10, 10 ', 10' 'ceramic absorber elements with channels vertical 11,

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second upper perforated cover 18 (or also expanded metal),

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second clamping plate 20 (with lattice of holes 16), screwed or riveted in the housing of the absorber (chamber 40),

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housing with folded side plates fifty.

Schematically a stack of three has been drawn absorber elements 10, 10 ', 10' 'located one above the other. In this configuration can be placed 12 absorber elements in a flat on the lower clamping plate in the housing of the absorber According to the power range of the installation of distribution and camera size there is also the possibility that a single monolithic absorber element fill all the camera section.

One of the grating plates 12 and 20 may, however, also be present comprehensively up and down in the absorber housing, forming together with the vertical uprights a robust housing frame. The housing of absorber 40 has a peripheral folded sheet flange with fixing holes 45 to screw the modular unit into, on or within a functional unit (GAS, LS). The material of sheet and sheet thickness may be different depending on the pressure behavior required. Screwing to the point of assembly can be done either by means of individual screws or by threaded bolts welded in the absorber housing of the modular unit According to the embodiment there is also the possibility of screwing with nuts fixed in the absorber housing by welding or riveting. According the pressure requirements to be met by the superstructure there is the possibility of screwing with nuts cage placed on the sheet of the housing.

Another possibility of screwing for high pressure requirements are offered by threaded studs or thread profiles that rest on the fixing fold and that through the union they guarantee a very firm union with the unit functional.

In the distribution facilities and cells of switching with gas isolation you have the possibility of make a multi-stage structure of absorber elements 40, the modular unit being directly positioned behind the bursting disk BS of the installation part of distribution or of the isolated switching cell to the gas GAS, and / or on the back face or in a pressure relief channel performed independently 60 (see Fig. 3 to Fig. 5).

Examples are shown in Fig. 6 and Fig. 7 of applications in LS switching cells with isolation by air. The modular unit is mounted for pressure relief outside of the switching cell on an upper end of the cell. The Switching cell has only one waterproof enclosure (Fig. 6). At case of switching cells with several watertight enclosures (Fig. 7) one complete unit or one unit is mounted for each enclosure watertight.

With respect to the details of Fig. 3 to 7, also refers to the list of references in which the concepts and abbreviations.

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Reference signs

10

Absorber elements (10, 10 ', 10' ')

eleven

Longitudinal channel

12

First clamping plate

14

(optional) first perforated sheet or metal plate expanded

16

Lattice holes

18

(optional) perforated cover (or second plate expanded metal)

twenty

Second clamping plate

40

Chamber, absorber housing

42

Frame

44

Flange

Four. Five

Holes

46

Asparagus

fifty

Side plate

60

Flow outflow path (discharge channel of the pressure)

80

Direction of flow (gas flow)

AF

Installation Front

NVR

Low voltage enclosure

LSR

Power switch enclosure

LS

Power switch

KAR

Cable connection enclosure

SSR

Busbar Enclosure

BS

Burst disk

GAS

Distribution installation or invention cell hermetically sealed gas insulated

GG

Gas-filled switching housing

AB

Connection zone

AT

Drive zone

LS

Distribution installation isolated by air

Claims (15)

1. Modular unit for housing of at least one element (10, 10 ', 10'') for the absorption or damping of hot exhaust gases caused by an electric arc in high and medium voltage electrical functional units, in particular in distribution facilities where an evacuation channel or a defined evacuation route (60) is provided for gas evacuation and within which at least one absorber element (10, 10 ', 10'') is provided, presenting the modular unit a chamber (40) existing in the evacuation channel or the evacuation route (60), fills with at least one absorption element (10, 10 ', 10''), characterized in that inside the chamber (40) is located at least one monolithic absorption element (10, 10 ', 10'') made of ceramic material, and because the absorber element (10, 10', 10 '') is provided with channels (11 ) for the passage of gases. 2. Modular unit according to claim 1, characterized in that the material of the absorber element (10, 10 ', 10'') has an open porosity of 8 to 25%. 3. Modular unit according to one of the preceding claims, characterized in that the holes in the channels (11) are made in such a way as to ensure protection against contact (IP protection). 4. Modular unit according to claim 3, characterized in that the section of the holes of the channels (11) is of the order of 2 to 10 mm. 5. Modular unit according to one of the preceding claims, characterized in that the channels (11) run in the direction (80) of the main gas flow. 6. Modular unit according to one of the preceding claims, characterized in that a perforated cover is arranged on the absorber elements (10, 10 ', 10''), the size of the holes is made in such a way as to achieve protection against the contact (IP protection). 7. Modular unit according to one of the preceding claims, characterized in that the absorber elements (10, 10 ', 10'') are supported in the chamber (40) with fasteners (12, 20). 8. Modular unit according to one of the preceding claims, characterized in that a perforated metal plate (14) is located on the input side of the gases to the absorption elements (10, 10 ', 10''). 9. Modular unit according to one of the preceding claims, characterized in that it is arranged more than one absorber element (10, 10 ', 10''), one after the other. 10. Modular unit according to claim 9, characterized in that the channels (11) of the absorber elements (10, 10 ', 10'') arranged one after the other have equal sections of the overall flow section that are decreasing. 11. Modular unit according to one of the preceding claims, characterized in that the modular unit (40) is manufactured as a compact unit and is equipped with fixing means (45, 46) for placing it in parts of the housing of a functional unit (LS, GAS). 12. Modular unit according to claim 11, characterized in that the modular unit (40) is placed as a compact unit in a rack and the frame can be joined with parts of the housing of a modular unit (LS, GAS) via means of fixing made as a flange joint. 13. Modular unit according to one of the preceding claims, characterized in that the modular unit (40) is located directly behind the bursting disc (BS) of a gas insulated distribution system (GAS). 14. Modular unit according to one of claims 1 to 12, characterized in that the modular unit (40) is located at the end of a housing part of a functional unit (LS, GAS) made as an escape route (60). 15. Modular unit according to one of claims 1 to 12, characterized in that the modular unit (40) is used in stations and enclosures of practicable and non-practicable distribution facilities.