The invention relates to the field of high-voltage engineering, in particular high-voltage circuit breakers in electrical power distribution systems. It is based on a method and a high-voltage circuit breaker in accordance with the precharacterizing clause of the independent patent claims.
In EP 1 444 713 B1 a flow-guiding device for a circuit breaker is disclosed, which device coaxially encloses the quenching-gas flow and has an outer surface or shell having two outflow openings. The outer surface of the flow-guiding device defines an exhaust gas volume. Partial flows of the quenching-gas flow emerge from the outflow openings into the breaker chamber volume. The outflow directions of the directly opposite outflow openings are directed such that they intersect one another. This means that the quenching gas is favourably mixed once it has passed through the respective outflow openings. The outlet openings may have associated additional swirling bodies or baffle plates in order to additionally swirl the quenching gas leaving the outlet openings. Owing to the mixing and swirling, the quenching-gas flow is decelerated at the inlet into the breaker chamber volume, is cooled and is dielectrically recovered in order to avoid flashovers to the breaker chamber housing.
In DE 102 21 580 B3 a high-voltage circuit breaker having an interrupter unit is disclosed, in which the exhaust gases are deflected twice through 180°. In order to improve the cooling of the gases, a concentrically arranged, hollow-cylindrical perforated plate, through which a flow passes radially, is provided on the fixed-contact side. The perforated plate serves as a heat sink which draws heat from the quenching gas. The perforated plate does increase the flow resistance for the quenching gas. In the region of the perforated plate a uniform, laminar quenching-gas flow is maintained.
In the utility model DE 1 889 068 U a switch disconnector with improved exhaust gas cooling is disclosed. The cooling apparatus comprises a plurality of pipes which are arranged concentrically in the gas outflow channel, each of which have diametrically opposing outflow openings, such that in the case of laminar outflow the quenching gases must traverse a labyrinth-like path with numerous deflections and must touch large surfaces of the cooling pipes. With this arrangement, the outflow path is prolonged and the cooling surface in the exhaust is enlarged.
In the EP 1 403 891 A1 a circuit breaker is disclosed, in which exhaust gas is likewise guided from an arcing chamber through a hollow contact into a concentrically arranged exhaust volume and from there into a quenching chamber volume which is positioned further outwards. In order to increase the breaking capacity or rating, at least one intermediate volume and possibly a secondary volume are arranged concentrically between the hollow contact and the exhaust volume and are separated from one another by intermediate walls which have holes or gas passage openings. Owing to the radial outflow of the quenching gases from the inner volumes to the outer volumes, the exhaust gases are directed in the form of jets onto the intermediate walls of the volumes and are swirled. Thus, heat is highly efficiently transmitted into the intermediate walls by turbulent convection.
The passage openings between the hollow contact volume, the intermediate volume and possibly the secondary volume are arranged such that they are offset with respect to one another on the circumference. The passage openings between the secondary volume and the exhaust volume are arranged such that they are offset with respect to one another on the circumference and/or in the axial direction. As a result, meandering or else helical exhaust gas paths are defined, the transit or dwell time of the exhaust gas in the exhaust region is increased, and the heat removal from the exhaust gas is improved. Overall, in addition to the hollow contact volume, the exhaust volume and the breaker chamber volume, at least one further intermediate volume is therefore also required in the circuit breaker in order to increase the efficiency of the exhaust gas cooling.
In the previously known breakers, cold gas which resides in the interrupter unit prior to the switching operation is forcibly displaced by hot exhaust gas flowing out of the arc zone and pushed out of the exhaust. The cold gas component to be forcibly displaced impedes the outflow of the hot exhaust gases and is wasted, without being used for cooling purposes.
The invention is based on the prior art according to the U.S. Pat. No. 4,471,187. This document discloses a high voltage circuit breaker having a dedicated exhaust design comprising a storage volume for cold gas. The exhaust gas or arc-quenching gas coming from the arc-quenching zone is split up into two partial gas flows. The first partial gas flow bypasses the cold-gas storage volume and directly flows off into the breaker chamber through an exhaust opening. The second partial gas flow traverses the cold-gas storage volume, thereby forcibly displaces the cold gas and urges it to enter the breaker chamber, as well. The exhaust opening for the first partial gas flow and the outflow opening of the displaced cold gas flow are arranged in vicinity of one another at the entrance for exhaust gas into the breaker chamber. Therefore, the hot first partial gas flow and the displaced cold gas flow are not mixed together until they enter the breaker chamber. Furthermore, in both the hot and cold gas flows, turbulences or eddies are avoided and a laminar flow behaviour is maintained to the extent possible in order to achieve a high throughput rate of are-quenching gas flowing off from the arc-quenching zone through the exhaust region into the breaker chamber housing.
The object of the present invention is to specify a method for cooling a quenching gas in an electrical breaker device and an associated electrical breaker device having an improved circuit breaker rating. This object is achieved according to the invention by the features of the independent claims.
The invention consists in a method for cooling a quenching gas in an electrical breaker device for electrical power supply systems, in particular in a high-voltage circuit breaker, the breaker device comprising a breaker chamber which is surrounded by a breaker chamber housing, wherein in the event of a switching operation hot quenching gas flows from an arc-quenching zone to an exhaust region filled with cold gas, and wherein the hot quenching gas is split up into at least two partial gas flows, wherein further at least part of the cold gas is intermediately stored in the exhaust region, and the first partial gas flow is guided to bypass the intermediately stored cold gas and flows off or away into the breaker chamber, and with the aid of the second partial gas flow the intermediately stored cold gas is forcibly displaced out of the exhaust region, wherein further the first partial gas flow and the intermediately stored cold gas are mixed with one another in a mixing zone before flowing off into the breaker chamber housing. Owing to the intermediate storage of the cold gas and the mixing with the first hot partial gas flow, this hot partial gas flow is efficiently cooled. This cooling takes place at a very early moment when the first partial gas flow flows out of the arc-quenching zone. Cold gas present in the exhaust volume is not forcibly displaced out without being used, but rather is used for exhaust gas cooling. The displacement of the cold gas out of the intermediate storage volume is effected by the second partial gas flow, in particular by this second partial gas flow flowing through the intermediate storage volume, or by the intermediate storage volume being reduced in size owing to this second partial gas flow, for example by gas pressure being exerted on a movably positioned wall of the intermediate storage volume, or by said second partial gas flow producing a low pressure and, as a result, sucking the cold gas out of the intermediate storage volume, by a combination of such effects or in another manner. Owing to the improved cooling, the quenching gas undergoes more effective dielectric recovery than was previously the case, the circuit breaker rating can be increased, and/or the breaker chamber housing can be dimensioned to be more compact, in particular narrower, without the risk of electrical flashovers between the quenching gas flowing off and the breaker chamber housing.
The exemplary embodiments specify advantageous geometries and preferred dimensioning criteria for the exhaust region and, in particular, for the intermediate storage volume, the mixing zone and an optional mixing channel.
The exemplary embodiments have the advantage that the first partial gas flow flows out of the exhaust essentially at the same time as the stored cold gas, which is forcibly displaced out of the exhaust region and, in particular, out of the intermediate storage volume by the second partial gas flow.
Further the disclosed exemplary embodiments specify different variants and installation locations for auxiliary means with which the quenching gas can additionally be cooled. With advantage, the first and/or second partial gas flow is additionally cooled by the formation of gas jets and swirling of gas jets on a baffle wall.
One further aspect of the invention is also an electrical breaker device for an electrical power supply system, in particular a high-voltage circuit breaker. The breaker device comprises a breaker chamber which is surrounded by a breaker chamber housing and has an arc-quenching zone and an exhaust volume for cooling hot quenching gas, an exhaust region of the exhaust volume being filled with cold gas at the beginning of a switching operation, means being provided for splitting the hot quenching gas up into at least two partial gas flows, in addition an intermediate storage volume being provided in the exhaust region for storing cold gas, a first means being provided which guides the first partial gas flow into the breaker chamber housing whilst bypassing the intermediate storage volume, and a second means being provided which guides the second partial gas flow towards the stored cold gas and, as a result, causes the stored cold gas to be forcibly displaced out of the intermediate storage volume, wherein further a mixing zone is provided in the region of an outlet opening of the intermediate storage volume for mixing the first partial gas flow with the cold gas such that the first partial gas flow and the intermediately stored cold gas are mixed with one another before flowing off into the breaker chamber housing.
Other exemplary embodiments specify preferred design embodiments for the intermediate storage volume.
Further embodiments, advantages and applications of the invention are given in the dependent claims, in the combinations of claims as well as in the description which now follows and the figures.
There are shown schematically in:
In the figures same reference symbols are used for identical parts and repetitive reference symbols may be omitted.
In the quenching gas cooling method, the second partial gas flow 11b is guided towards the intermediately stored cold gas 111 in order to forcibly displace it directly or indirectly out of the exhaust volume 7, 8.
The intermediately stored part of the cold gas 111 is advantageously stored intermediately in the exhaust region in a cold-gas reservoir or intermediate storage volume 7, 8, the intermediate storage volume 7, 8 having an inlet opening 70 and an outlet opening 80 for the second partial gas flow 11b and the optional, further assisting partial gas flow 11c and having, in the region of the outlet opening 80, a mixing zone 12, in which the stored cold gas 111 is mixed with the first partial gas flow 11a.
Preferably, a low pressure is produced in the region of the mixing zone 12 by the first partial gas flow 11a, by which low pressure the intermediately stored cold gas 111 is sucked out of the intermediate storage volume 7, 8. The sucking may be effective on its own or in support of the forcible displacement of the cold gas. Furthermore, a mixing channel 10 can be present before or downstream of the mixing zone 12 and after or upstream of the inlet into the breaker chamber 2 or breaker chamber housing 3, and the first partial gas flow 11a can be mixed in the mixing channel 10 with the intermediately stored cold gas 111 and in particular with a precooled second partial gas flow 11b and optionally a third or further partial gas flow 11c. The mixing channel 10 is an optional element. For example, it is also possible for gas jets to be formed in the first partial gas flow 11a and in the forcibly displaced cold-gas flow 111 and to be directed towards one another such that they swirl one another in the region of the mixing zone 12 and are mixed. In particular, the hot and cold gas jets form eddies with one another to achieve a turbulent mixture of the first partial gas flow 11a and the cold gas 111 before flowing off into the breaker chamber housing 3. As a result, even without or in addition to the mixing channel 10, the quenching gas 11 is effectively cooled before it flows off or when it flows off into the breaker chamber housing 3.
Preferably, the storage capacity of the intermediate storage volume 7, 8 shall be designed according to a desired mixing duration and mixing temperature of the first partial gas flow 11a with the intermediately stored cold gas 111. In addition, a path difference between the longer path and the shorter path can be designed to be equal to a throughflow length through the intermediate storage volume 7, 8. For example, as shown in
Particularly preferred, the first partial gas flow 11a flows out into the breaker chamber housing 3 along a minimum path whilst bypassing the intermediate storage volume 7, 8; and/or the second partial gas flow 11b flows out into the breaker chamber housing 3 along a maximum path through the intermediate storage volume 7, 8; and/or a further partial gas flow 11c (
Furthermore, the quenching gas 11 can be precooled using auxiliary means for precooling 9, 9a, 9b, 9c; 74, 75 in the exhaust volume 4 of the breaker device 1 (
The subject matter of the invention is also an electrical breaker device 1, which will be explained in more detail first with reference to
At the beginning of a switching operation, an exhaust region 7, 8 of the exhaust volume 4 is filled with cold gas 111. Means 71, 72, 73; 7a, 7b; 8a, 8b for splitting the hot quenching gas 11, 110 up into at least two partial gas flows 11a, 11b, 11c are provided. In the exhaust region 7, 8 an intermediate storage volume 7, 8 for storing cold gas 111 is arranged, a first means 71; 101, 102 being provided which guides the first partial gas flow 11a into the breaker chamber housing 3 whilst bypassing the intermediate storage volume 7, 8, and a second means 7a, 7b, 72 being provided which guides the second partial gas flow 11b towards the stored cold gas 111 and, as a result, causes the stored cold gas 111 to be forcibly displaced out of the intermediate storage volume 7, 8.
In
A mixing zone 12 is provided in the region of an outlet opening 80 of the intermediate storage volume 7, 8 for mixing the first partial gas flow 11a with the cold gas 111, which is stored in the intermediate storage volume 7, 8 and which is forcibly displaced out of the intermediate storage volume 7, 8 by the second partial gas flow 11b, such that the first partial gas flow 11a and the intermediately stored cold gas 111 are mixed with one another before flowing off into the breaker chamber housing 3.
The mixing zone 12 can at the same time be in the form of a low pressure zone 12 for sucking the stored cold gas 111 out of the intermediate storage volume 7, 8. This can be achieved, for example, by the flow ratios and, in particular, the flow rates of the partial flows 11a, 11b and possibly 11c in the region of the low pressure zone 12. Furthermore, the mixing zone 12 can also be in the form of a swirling zone 12 for the first partial gas flow 11a and the cold gas 111 and, in particular, for gas jets of the first partial gas flow 11a and of the cold gas 111.
Furthermore, a mixing channel 10 can be arranged after or downstream of the mixing zone 12 and before or upstream of the inlet into the breaker chamber housing 3, in which mixing channel 10 additional mixing of the first partial gas flow 11a with the cold gas 111, which has been forcibly displaced out of the intermediate storage volume 7, 8, and, in particular, with a precooled second partial gas flow 11b and possibly a further partial gas flow 11c takes place. The mixing channel 10 is, for example, separated from the intermediate storage volume 8 by an inner channel wall 10a and is connected to it via a channel inlet opening 101. The channel inlet opening 101 therefore acts as an outflow opening out of the intermediate storage volume 7, 8, and the channel outlet opening acts as an actual exhaust opening 102. The mixing channel 10 has a diameter D and has a length L between the channel inlet opening 101 and the channel outlet opening 102. The diameter D and the length L should be dimensioned such that efficient mixing of the already premixed partial gas flows 11a, 11b, 11c with the cold gas 111 and with one another is realized. The mixing channel 10 may be aligned or oriented axially (
The storage capacity of the intermediate storage volume 7, 8 is dimensioned such that a desired mixing duration and mixing temperature of the first partial gas flow 11a with the intermediately stored cold gas 111 can be achieved. As well, the throughflow length, for example 2*1 in
In order to provide a minimum path for the first partial gas flow 11a, the first opening 71 is preferably arranged close to the outflow opening 101, in particular radially opposite the outflow opening 101; and/or, in order to provide a maximum path for the second partial gas flow 11b, the second opening 72 is arranged far removed from the exhaust outflow opening 101, in particular at a maximum axial distance from the outflow opening 101; and/or a third or further opening 73 is arranged for a further partial gas flow 11c in the axial direction 1a between the first and the second openings 71, 72 (
Preferably, the second opening 72 interacts with a deflecting device 7b, 8b, 8a for guiding the stored cold gas 111 and the second partial gas flow 11b back towards the outlet opening 80 of the intermediate storage volume 7, 8; and/or the path length difference between the shorter path 11a for the first partial gas flow and the longer path 11b for the second partial gas flow is given by the axial distance between the first and the second openings 71, 72. The openings 71, 72, 73 may be holes or slots in a wall 7a, 7b of the body 7a, 7b, 8a, 8b. The openings 71, 72, 73 can be arranged in a radial wall 7a and/or in an axial wall 7b of the body 7a, 7b, 8a, 8b. A number, size (i.e. cross-sectional area A1, A2, A3) and position of the first, second and possibly third openings 71, 72, 73 can be designed such that the first partial gas flow 11a can still largely be mixed in the exhaust volume 4 with the stored cold gas 111. In particular, a plurality of holes or slots 72 and possibly 73 shall be arranged on the circumference and/or along the axial extent in the body 7a, 7b, 8a, 8b through which a flow can pass such that a hot-gas front is formed in the second and possibly further partial gas flows 11b, 11c and no cold-gas pockets remain in the intermediate storage volume 7, 8. In the region of the openings 71, 72, 73, the total throughflow cross section A0=A1+A2, possibly A0=A1+A2+A3, is typically at its smallest and the throughflow rate is at its greatest.
The body 7a, 7b, 8a, 8b through which a flow can pass may comprise an inner cylinder 7a, 7b and an outer cylinder 8a, 8b. The inner cylinder and the outer cylinder 7a, 7b, 8a, 8b are preferably arranged coaxially with respect to one another and with respect to the breaker axis 1a. The inner cylinder and the outer cylinder 7a, 7b, 8a, 8b delimit the intermediate storage volume 7, 8 radially by means of at least two outer or cylinder surfaces 7a, 8a and axially at the ends by means of associated base surfaces 7b, 8b. The inner cylinder 7a, 7b defines an inner volume V1 and has an inlet opening 70 towards the arc-quenching zone 6 for the second partial gas flow 11a. The outer cylinder 8a, 8b surrounds the inner cylinder 7a, 7b, defines an outer volume V2 and has an outlet opening 80 towards the arc-quenching zone 6 for the stored cold gas 111 and the second partial gas flow 11b. The inner cylinder 7a, 7b and the outer cylinder 8a, 8b are connected to one another by means of the second opening 72 and possibly the third opening 73. The inner and outer volumes V1, V2 shall preferably be matched to one another such that a desired storage capacity for the cold gas 111 and a desired throughflow dynamics for the second partial gas flow 11b can be realized.
The intermediate storage volume 7, 8, the first means 71; 101, 102 and the second means 7a, 7b, 72 can be arranged in the exhaust region 7, 8 of a first and/or a second contact 5 of the breaker device 1. The breaker device 1 may be a high-voltage circuit breaker 1 or a high-current circuit breaker or a switch disconnector or the like.
In detail,
Auxiliary means 9, 9a, 9b, 9c; 74, 75 for precooling the quenching gas 11 can be arranged in the exhaust volume 4 of the breaker device 1. The auxiliary means 9, 9a, 9b, 9c; 74, 75 can be arranged in the hot-gas flow 110 before it is split up into the partial gas flows 11a, 11b, 11 and/or in the first partial gas flow and/or in the second partial gas flow 11a, 11b and possibly in the further partial gas flow 11c. Such auxiliary means relate, on the one hand, to jet-forming outflow openings 74 in the intermediate storage volume 7, 8 and/or in a secondary volume 9a for forming gas jets as well as a baffle wall 75 for swirling purposes and intensive turbulent convective cooling of the gas jets. Further details on this cooling mechanism can be gleaned from the European patent application EP 1 403 891 A1, published before the priority date, and the international patent application PCT/CH2004/000752, not published before the priority date, which are hereby incorporated by reference in the description to their entire disclosure content. In particular, an outflow or ejection characteristic of the openings 71, 72, 73 can be matched to a distance from the opposite baffle wall 75, for example the outer wall 8a or rear wall 8b of the outer cylinder 8a, 8b, such that the eddies are formed at or in the region of the baffle wall 75. In addition, the quenching gas and in particular the eddies can be guided on circular paths, helical paths or on spiral paths. In particular, the circular paths, helical paths or spiral paths can be guided along the baffle wall 75 about the inner cylinder 7a, 7b towards the outflow opening 80 of the intermediate storage volume 7, 8. As shown in
Another aspect of the invention relates to a method for cooling a quenching gas 11 in an electrical breaker device 1 according to the preamble of the independent claim 1, wherein gas jets in the first partial gas flow 11a and in the cold gas 111 are produced and are directed towards one another in the region of a mixing zone 12, and, as a result, are mixed. In particular, the hot and cold gas jets form eddies with one another to achieve a turbulent mixture of the hot first partial gas flow 11a with the cold gas flow 111. The turbulent mixing of the hot and cold gas jets can occur during or before or after the exhaust gas 11; 11a, 11b, 11c; 110, 111; 13 is leaving the exhaust region 7, 8 and is entering the breaker chamber housing 3.
In yet another aspect, the invention relates to an electrical breaker device 1 according to the preamble of the independent claim 11, wherein a mixing zone 12 for mixing the first partial gas flow 11a with the cold gas 111 is provided in the region of an outlet opening 80 of the intermediate storage volume 7, 8, jet-forming means for forming gas jets of the first partial gas flow 11a and of the cold gas 111 are provided, and the mixing zone 12 serves as a swirling zone 12 for the gas jets of the first partial gas flow 11a and the cold gas 111. In particular, the hot and cold gas jets are directed towards one another in the mixing zone 12 and, as a result, form eddies with one another to achieve a turbulent mixture of the hot first partial gas flow 11a with the cold gas flow 111. The turbulent mixing of hot and cold gas jets can occur during or before or after the exhaust gas 11; 11a, 11b, 11c; 110, 111; 13 is leaving the exhaust region 7, 8 and is entering the breaker chamber housing 3.
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