DE9102514U1 - Medium-voltage electrical switchgear - Google Patents

Description

ABB Patents GmbH

Mannheim 27 February 1991

Mp. No. 91/528 PAT 4-Ni/Wi

Medium-voltage electrical switchgear Description

The invention relates to an electrical, metal-encapsulated medium-voltage switchgear for indoor installation, consisting of several switch panels arranged in a row, which preferably contain several compartments partitioned off from one another with various electrical switching or equipment elements and in which wall parts are opened for "exhaustion" in the event of an internal pressure increase, with the gas being discharged from the top of the switch panels.

In such switchgear, it is important to direct the arc discharge, if it has to be directed into the installation room, in a safe direction and to pre-cool it if possible. This has led to the "exhaust" being directed upwards or - away from the service corridor - to the rear. Metal grids for cooling at the point where the gases exit the switchgear panels are usually not effective, as excessive insulation must be avoided.

91/528 2 27 February 1991

The invention now aims to ensure that the arc gases leave the switchgear both at a reduced pressure and significantly cooled, and that this is done with a switchgear construction volume that is still favorable.

This task is solved by an expansion channel placed on the top of the switch panels and extending over them, into which the arc gases from the switch panels are directly introduced, that at least one further exhaust channel is present into which the arc gases are diverted via at least one connection opening and in at least one exhaust end of which a metal mesh, in particular expanded metal layers, is inserted - with the exhaust end or ends being directed parallel to the expansion channel.

The two channels initially create a considerable expansion space. The gases, which have been significantly depressurized, are additionally effectively cooled at the exhaust end by expanded metal layers; due to the size of the expansion space upstream, their insulating effect no longer has the previously described importance with regard to the bursting safety of the switchgear. Due to the diversion and the associated pre-cooling of the gases, the expanded metal layers are not subjected to excessive thermal stress. All of this makes it possible to release the arc gases from the exhaust channel in a direction along the operating corridor on the top of the switchgear. This makes advantageous use of the space above the switchgear, which must be available anyway when exhausting directly upwards; there is therefore no need to change the height of the installation space.

91/528 3 27 February 1991

The ends of the exhaust duct can be directed towards or against each other. It is important that there is sufficient space between them or between them and the nearest wall.

Optimum use of space is achieved when the ducts are arranged one above the other. They can be designed with the same depth, which is beneficial for the mounting of the exhaust duct.

A stable construction is advisable for the expansion channel. This can be achieved by a polygon - seen in cross-section.

An embodiment of the invention is shown schematically in the accompanying figures and will be explained in more detail below.

Show it:

Figure 1: Front view of a cellular switchgear; expansion and exhaust duct in section,

Figure 2 is a side view of the switchgear according to Figure 1 in section,

Figure 3 shows a variant of the switchgear in front view with the exhaust duct ends facing each other.

The cell-shaped switchgear is formed by switch panels la to In arranged in a row. As can be seen in Figure 2, such a switch panel Ic is made up of several compartments that are partitioned off from one another. For example, you can see a circuit breaker compartment 2, a busbar compartment 3 and a low-voltage compartment 4 running along the front that is higher than the other compartments.

91/528 4 27 February 1991

The compartments 2 and 3 can be relieved towards the top of the switchgear panel via flaps 5, 6 that open due to an internal overpressure. The flaps swing into the expansion channel 7 that runs along the top of the switchgear and covers the individual switchgear panels la to In. The latter will essentially be made up of opposing side walls 8, 9 and the roof plate 10, in which one or more connecting openings 11, 12, 13 are made - depending on the design. The expansion channel 7 can also be designed with a base plate that rests on the switchgear panels la to In, which then of course must contain openings for the flaps 5, 6 to swing in.

Viewed in cross-section (see Figure 2), the expansion channel is rectangular on the side facing the switch panels; while its upper, hood-like end has a trapezoidal shape due to the inward-drawn side walls 9. This increase in surface area gives the channel better mechanical stability.

Parallel to the expansion channel 7 - namely on its top - is the exhaust channel 14, which does not run across the entire switchgear row. It can be attached to the expansion channel 7 or directly to the top of the switchgear panels. According to Figure 1, the parallel channels 7, 14 are designed symmetrically to their connection opening 11, which is located approximately in the middle of the switchgear row.

Shortly before the outlet openings 15, 16, 17, 18 pointing in the longitudinal direction of the switchgear row, a cooling device in the form of multi-layer expanded metal 19 is accommodated in the exhaust duct end.

91/528 5 27 February 1991

According to Figure 2, the exhaust channel 14 is divided into two individual channels 14a, 14b, which are attached to the ends of the expansion channel 7. They are each designed with only one outlet opening 17, 18, which is directed towards the centre of the switchgear. The connecting openings 12, 13 are each placed over the end switch panels la and In. The individual channels 14a, 14b do not extend to the centre of the system; their outlet openings 17, 18 are located opposite each other at a suitable distance so that the arc gases ejected there have enough space to be able to escape into the installation room of the switchgear.

The arrows indicate the flow path of the arc gases, which are always diverted, out of the switchgear. It is important that a large expansion space is available, namely the content of the expansion channel, which extends over the entire system row (1 x h x a). Added to this is the volume of the exhaust channel, which can also provide a large exit cross-section, namely 2 x a x b, for the arc gases.

Claims (11)

91/528 1 27 Feb. 1991 Protection claims 1. Electrical, metal-encapsulated medium-voltage switchgear for indoor installation, consisting of several switch panels arranged in a row, which preferably contain several compartments with various electrical switching or equipment elements which are partitioned off from one another and in which wall parts are opened for "exhausting" when there is an internal pressure increase, with the gas being discharged from the top of the switch panels, characterized by an expansion channel (7) placed on the top of the switch panels (la to In) and extending over them, into which the arc gases from the switch panels are introduced directly, and that at least one further exhaust channel (14, 14a, 14b) is present, into which the arc gases are diverted via at least one connecting opening (11, 12, 13) and in whose at least one exhaust end a metal mesh, in particular expanded metal layers (19), is inserted, with the exhaust end or ends being guided parallel to the expansion channel. 2. Switchgear according to claim 1, characterized in that the connecting opening (11) between the channels (7, 14) is made approximately in the middle of the cell-shaped switchgear and the channels are arranged approximately symmetrically to the connecting opening (11), the exhaust channel (14) being designed with a significantly shorter length than the switchgear row. 91/528 2 27 February 1991 3. Switchgear according to claim 2, characterized in that the exhaust channel (14) has two outlet openings (15, 16). 4. Switchgear according to claim 1, characterized in that the exhaust channel is divided into two individual channels (14a, 14b), which are each attached to the ends of the expansion channel (7) and whose outlet openings (17, 18) are directed towards the center of the switchgear. 5. Switchgear according to claim 4, characterized in that the connecting openings (12, 13) of the channels (7, 14a, 14b) are each made above the switchgear end fields (la, In). 6. Switchgear according to claim 4, characterized in that the outlet openings (17, 18) of the individual channels (14a, 14b) - in the longitudinal direction of the switchgear - are arranged at a distance from each other. 7. Switchgear according to one of the preceding claims, characterized in that the exhaust channel (14, 14a, 14b) is placed on the expansion channel (7). 8. Switchgear according to one of the preceding claims, characterized in that the exhaust (14, 14a, 14b) and the expansion channel (7) have the same depth (a). 9. Switchgear according to one of the preceding claims, characterized in that the expansion channel (7) - seen in section - is formed as a polyhedron. 91/528 3 27 February 1991 10. Switchgear according to claim 9, characterized in that the expansion channel (7) is rectangular in its lower part, directed towards the switchgear, and trapezoidal in its upper part with recessed side walls (9). 11. Switchgear according to one of the preceding claims, characterized in that the expansion and exhaust ducts are designed as prefabricated, type-tested switchgear components.