High-voltage switches with arc preventing or extinguishing devic – Arc preventing or extinguishing devices – Air-current blowout
Reexamination Certificate
2001-03-12
2002-09-03
Donovan, Lincoln (Department: 2832)
High-voltage switches with arc preventing or extinguishing devic
Arc preventing or extinguishing devices
Air-current blowout
C218S043000
Reexamination Certificate
active
06444937
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an interruption and disconnecting device for high- and/or medium-voltage applications, which contains dielectric insulation means and has a particular structure, so as to allow the reduction of the environmental impact of said insulation means.
2. Description of the Related Art
It is known that the interruption and disconnecting devices of the art generally comprise at least one interruption chamber and a disconnection chamber which are connected to insulating bushings. These elements are arranged inside a structure which is sealed with respect to the surrounding environment and is filled with a fluid insulating medium. With reference to
FIG. 1
, a block diagram is presented which illustrates an example of a typical structure of a known interruption and disconnecting device used in a high-voltage substation.
A conductor of a main power line, indicated by the arrow
2
, is connected to a main distribution bar
3
by means of the interruption and disconnecting device
1
. Said interruption and disconnecting device
1
comprises an insulating bushing
4
for connection to the line
2
. a disconnection chamber
5
, an interruption chamber
6
, electric current measuring devices
7
and
8
arranged at the ends of the interruption chamber
6
, and an insulating bushing
9
for connection to the bar
3
by means of a conductor
10
. There are also two devices
11
and
12
used to earth the system.
The disconnection chamber
5
can be arranged both upstream and downstream of the interruption chamber
6
.
The device
1
is completely filled with an insulating medium in order to prevent electrical discharges between the various parts that are at high potential differences.
A known embodiment of an interruption and disconnecting device according to the block diagram of
FIG. 1
is presented with reference to FIG.
2
. The insulating bushings
4
and
9
are arranged respectively in input and in output with respect to the interruption and disconnecting device
1
. The insulating bushing
4
contains the conductor
2
of the main power line, while the insulating bushing
9
contains the conductor
10
connected to the main distribution bar (not shown in FIG.
2
).
The insulating bushing
4
is connected to the disconnection chamber
5
by means of a coupling
13
. The disconnection chamber
5
contains a fixed contact
14
and a moving contact
15
for performing disconnection. An earthing device
11
is also connected to the chamber
5
and connects, if required, the main conductor
2
to the outer casing,
16
of the device
1
, which is at ground potential by means of the supports
17
,
18
and
19
. Actuation elements
20
for moving the moving contact
15
are also placed inside the disconnection chamber
5
. The disconnection chamber
5
is furthermore separated from the insulating bushing
4
and from the disconnection chamber
6
by means of the insulating partitions
21
and
22
.
The interruption chamber
6
contains a moving contact
23
and a fixed contact
24
. The moving contact
23
is actuated by movement elements
25
. Further, the earthing device
12
is connected to the interruption chamber
6
and places the conductor
26
in output from the disconnection chamber at ground potential. The moving contact
23
is connected to the conductor
10
in output from the interruption and disconnecting device
1
. The interruption chamber
6
is separated from the insulating bushing
9
by means of the insulating partition
28
. The insulating bushings
4
and
9
, the interruption chamber
6
and the disconnection chamber
5
are completely filled with an insulating fluid, generally sulfur hexafluoride (SF
6
), having a pressure which is higher than the atmospheric one. In order to maintain said internal pressure, required in order to achieve reduced insulation distances and therefore reduce the dimensions of the structure. the device
1
is completely sealed with respect to the outside environment.
Alternative configurations with respect to the one described in
FIGS. 1 and 2
are possible. In particular, it is possible to use multiple disconnection chambers and multiple insulating bushings if it is necessary to connect multiple distribution bars to the main power line.
In the interruption and disconnecting devices of the art, the insulation fluid that is generally used is sulfur hexafluoride (SF
6
). Other known fluids are fluorocarbons (FC), perfluorocarbons (PFC), perfluoropolyethers (PFPE) or mixtures thereof.
The use of these insulation means, particularly SF
6
, which has the highest dielectric insulation capacity, allows to considerably reduce the insulation distances and therefore to considerably reduce the dimensions of each single device, and therefore of the substation in which it is used, with respect to the use of insulating means, such as mineral oils. This fact leads to a considerable reduction in installation and operating costs.
It is known from the technical literature that known fluoridized gaseous insulating means, in particular SF
6
, may cause problems in terms of environmental impact; furthermore they are considerably expensive.
Reducing the content of these insulating means by using alternative dielectric fluids, such as for example mixtures of SF
6
and nitrogen (N
2
), pure nitrogen or noble gases leads to an increase in the required insulation distances, since said alternative fluids have, for an equal pressure, a much lower dielectric strength and arch quenching power than, for example, SF
6
used in its pure state. Simple replacement of SF
6
with other alternative insulation fluids without performing any structural modification to the interruption and disconnecting device would cause malfunctions.
On the other hand, if the pressure of said alternative insulating fluids is increased so as to ensure satisfactory dielectric strength and arc quenching power, it is necessary to resort to complicated structures which are economically scarcely competitive and scarcely reliable.
BRIEF SUMMARY OF THE INVENTION
The aim of the present invention is to provide an interruption and disconnecting device for high- and/or medium-voltage applications, whose structure has a reduced complexity and is capable of optimizing the use of the insulation means used, so as to considerably reduce their environmental impact.
Within the scope of this aim, an object of the present invention is to provide an interruption and disconnecting device for high- and/or medium-voltage applications. which has a modular structure which allows to partition the volume of the insulating fluids used inside the interruption pole.
Another object of the present invention is to provide an interruption and disconnecting device for high- and/or medium-voltage applications, in which it is possible to use different insulation means inside the interruption pole.
Another object of the present invention is to provide an interruption and disconnecting device for high- and/or medium-voltage applications, which allows easy maintenance and/or replacement of the electric actuation elements, particularly of the parts that are most exposed to wear, such as the fixed contact and the moving contact of the interruption chamber.
Another. but not last, object of the present invention is to provide an interruption and disconnecting device for high- and/or medium-voltage applications. which is highly reliable and relatively easy to manufacture and at competitive costs.
This aim. these and other objects, which will become more apparent hereinafter, are achieved by an interruption and disconnecting device for high- and/or medium-voltage applications, comprising a disconnection chamber and an interruption pole having a free volume accommodating an interruption chamber which contains a moving contact and a fixed contact, said interruption pole and said disconnection chamber containing dielectrically insulating fluids. The device according to the invention is characterized in that said interruption chamber is sealed.
In this way. the de
ABB Trasmissione & Distribuzione SpA
Donovan Lincoln
Fishman Marina
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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