CN101006539A - Large power switch - Google Patents

Abstract

A heavy-duty circuit breaker can be filled with a quenching gas and comprises a first (1) and a second arcing contact piece (2) and a heating chamber (11) for temporarily storing quenching gas heated by an arc (4). An insulating nozzle (5) is provided with a throat (6) in order to direct a quenching gas flow (s3) along an axis (A). An expanded zone (21) adjoins said throat (6) which is provided with a cross-sectional area F that extends perpendicular to the axis (A) in the vicinity of the expanded zone (21). A distance d between the throat (6) and the second arcing contact piece (2), which is measured along the axis (A), lies within a specific range at least as long as the quenching gas (s3, s4) can at least locally flow at sonic or supersonic speed in the course of a switching-off process once the contact has been separated during a quenching phase in which quenching gas is able to flow (s3) through the throat (6) in the direction (z2) of the second arcing contact piece (2), at least when the quenching gas can at least locally flow (s3, s4) at sonic or supersonic speed. Said range is given by the fact that the cross-sectional area available for penetration by the quenching gas flow (s3) in the expanded zone (21) corresponds at least to the area F, especially at least 1.5 times the area F, while the minimum quenching gas density prevailing in the throat (6) or between the throat (6) and the second contact piece (2) is greater than the minimum quenching gas density prevailing in or next to the second contact piece (2).

Description

high power switch

technical field

The invention relates to the field of high voltage switch technology. The invention relates to a high-power switch and a method for switching off the high-power switch according to the preambles of the independent claims.

Background technique

Such high-power switches have been known from the prior art for almost ten years. They have two arcing contacts and are filled with quenching gas. After contact separation, an arc may burn between the contacts. A heating chamber is provided for temporarily storing the quenching gas heated by the arc. An insulating nozzle has a constriction for guiding a flow of quenching gas, which is connected to the heating chamber. The arc is extinguished by the flow of arc extinguishing gas. A switch of this type can advantageously be formed as a damper switch (pneumatic piston switch) or as a self-pneumatic switch (Selbst-blasschalter) or as a combined damper switch-self-pneumatic switch combination.

For reliable switch-on, flashback must not occur during so-called oscillations of the recovery voltage, which produces high voltage peaks during the switch-on process immediately after the current zero crossing. Especially for terminal short circuit (T100a), it is difficult to reliably avoid such back arcing with reference to IEC-Norm 62271-100, and it is difficult to guarantee reliable extinguishing of the arc. It is desired to improve the switching characteristics accordingly.

Contents of the invention

It is therefore the object of the present invention to provide a high-power switch and a method for switching off a high-power switch of the type described above which have an improved switching behavior. In particular, back arcs threatened by the generation of the recovery voltage, in particular terminal short circuits (T100a), can be reliably prevented and reliable extinguishing of the arcs is ensured.

This object is achieved by a device and a method having the features of the independent claims.

The high-power switch according to the invention can be filled with an quenching gas (eg SF ₆ , N ₂ , air or a mixture thereof) and has a first arcing contact and a second arcing contact. After the contacts separate, an electric arc may burn between the two arcing contacts. In order to temporarily store the quenching gas heated by the arc, the high-power switch has a heating chamber. An insulating nozzle has a constriction connected to the heating chamber for guiding the quenching gas flow along the axis. A widening point adjoins the narrowing point.

The high-power switch according to the invention is characterized in that a distance d, measured parallel to the axis, between the constriction and the second arcing contact is at least during a critical time interval for a possible back arc at least during the special contact Usually within a distance interval. The advantage achieved by this is that in this way the possibility of back arcing due to an inrush voltage (transient recovery voltage, TRV) lasting only a few hundred microseconds or due to the recovery voltage is greatly reduced . This is achieved by selecting the distance d along the connecting path, that is, between the two contacts according to the invention, in a particular field loading area, but at least in narrow areas and in narrow areas A relatively high quenching gas density and thus a relatively high compressive strength are achieved with the second contact.

It is necessary to design a high-power switch in such a way that it can switch reliably different switching situations, such as distance short-circuits ("short-line fault", L90) and terminal short-circuits (T100a). The details for defining the different switching situations are stored in IEC-Norm 62271-100. For distance short circuits, generally higher quenching gas pressures are required for thermal quenching. This mostly leads to the fact that in the event of a terminal short circuit (T100a) there is so much quenching gas pressure that there is a supersonic flow. In supersonic flows, shock waves and corresponding wave patterns generally occur, which are generated in the expansion. This results in a region with a relatively low quenching gas density (and correspondingly low quenching gas pressure) in the expansion. Pressures (and corresponding densities) arise here, which can be significantly lower than the quenching gas filling pressure (background pressure) present in the switch under normal conditions.

According to the invention, the second contact can be positioned in such a way that the region of lowest quenching gas density does not occur along the contacting path section, but on the side of the second contact. For this it is necessary to position the contacts relatively close to the stenosis, for example substantially at the first (and therefore most pronounced) density minimum, if the second contact is (infinitely) far away from the stenosis (or if there is no first contact at all). two contacts). By adapting the positioning of the second contact according to the invention, the flow characteristics in the widening are changed such that the minimum value of the arc-extinguishing gas density generated in or next to the second contact is lower than in the constriction or at the constriction The minimum value of the arc extinguishing gas density generated between the second contact. A relatively high quenching gas density and thus a relatively high compressive strength are thus achieved along the connection path section. Back arcing can thus be effectively prevented.

However, the distance d cannot be selected to be too small, since otherwise too great a hindrance to the quenching gas flow would result, so that the quenching gas pressure would not decrease rapidly enough in the heating chamber and a sufficient arc load would not be achieved. It is also necessary to make the distance d at least so large that the smallest cross-sectional area to be passed by the quenching gas flow in the expansion has an area at least as large as the cross-sectional area of the constriction (closer to the expansion), Preferably at least 1.5 times, at least 2 times or at least 2.5 times or even at least 3 times this area.

In the prior art, the distance d is generally chosen to be very large, whereby a large separation of the two arcing contacts is generally achieved, which also leads to a lower possibility of breakdown because the electric field generated Less intense. However, such a large distance d is contrary to the concept of the invention, since a very low density of the quenching gas exists in the area in front of the contacts.

The density and the pressure of the quenching gas are directly combined with each other via the (local) temperature of the quenching gas, and they are caused by the local flow velocity of the quenching gas, a high flow velocity being accompanied by a low density and a low pressure. Instead of being defined by the quenching gas density (next to or in front of the second contact), the invention can also be defined by the pressure there or by the flow rate of the quenching gas there. The advantage of defining by partial pressure is that pressure can be measured relatively well compared to density and flow velocity. All three parameters (density, pressure, flow rate) can generally be determined well in simulation calculations.

As mentioned above, the condition for the distance d is maintained at least during a time interval that is critical for a possible arc reversal. This time interval must lie during the opening process after the separation of the contacts, since otherwise no arc would be generated to be extinguished. The invention also works if the quenching gas flow is able to pass through the constriction in the direction of the second arcing contact. When, for example, the second contact is a suppression contact, that is sometimes in order to be able to build up a high quenching gas pressure in the heating chamber, the constriction is at least partially suppressed, thus starting a weighing is the time interval of the extinguished state during which a flow of quenching gas can pass through the constriction in the direction of the second arcing contact, at the earliest when said constriction is no longer suppressed by the second contact. The quenching gas then also flows from the heating chamber in the direction of the second contact through the constriction and into the expansion.

Furthermore, the invention can also function correctly if the quenching gas flow can flow at least locally at sonic or supersonic speeds, in particular at certain points in the expansion region. Since, in principle, the switching can be carried out as a function of the switching situation, and accordingly for different switching situations the movement sequences carried out by the contact and the nozzle during the switching operation can be selected differently, so the selection of the distance d according to the invention is It can be limited to those switching situations in which the quenching gas flow can flow at least locally at sonic or supersonic speed.

The distance d is selected in the manner according to the invention within a time interval, which is thus limited backwards, so that the distance d no longer needs to be at the interior of the distance interval described above. When the quenching gas pressure p _H in the heating chamber is reduced so much relative to the filling pressure p ₀ (static pressure, pressure in a displacement volume) that sonic and supersonic flows are no longer possible in the expansion, The distance d also no longer has to lie within the distance interval.

However, the second contact can also remain within the distance gap until the end of the disconnection process.

Depending on the quenching gas used, the Laval-pressure ratio gives the pressure ratio p ₀ /p _H at which a supersonic flow can be achieved. For SF ₆ the Laval-to-pressure ratio is about 0.59; for N ₂ it is about 0.53; for air it is also about 0.53. For a gas with an adiabatic coefficient k, the Laval-pressure ratio is:

[2/(k+1)] ^k/(k-1)

According to the invention, the distance d should lie within the distance interval, which can thus be given according to the above-described embodiments, on the one hand, corresponding to a lower distance interval limit for supplying the quenching gas flow in the extension has a cross-sectional area at least as large as the cross-sectional area of the constriction (near the extension); on the other hand, corresponding to an upper distance separation limit, at the constriction or between the constriction and the second contact The minimum value of the quenching gas density is greater than the minimum value of the quenching gas density generated in or next to the second contact. The fact that the minimum is located in the second contact can of course only occur if the second contact is a hollow contact, for example a tulip contact.

In one option of the invention, the nozzle and the second contact are selected in a suitable manner at least after the arc has been extinguished for the dielectric strengthening of the connection path and for the rapid passage of the arc-extinguishing gas through the extension. The distance between the heads d.

In another option, the high-power switch according to the invention can be characterized in that during the opening process after the contact is separated, during the extinguishing state-in this state, a kind of arc-extinguishing gas flow can be directed towards the second The direction of the arcing contact (in particular at least at the speed of sound) through the constriction - the distance d, measured parallel to the axis, between the constriction and the second arcing contact is chosen such that the flow velocity of the arc-quenching gas flow is at a point The middle is the largest, and this part is arranged beside the second arcing contact and/or is arranged inside the second arcing contact. The part can be related or consist of multiple sub-parts.

There is therefore also a time interval called the extinguished state, which is located after the separation of the contacts and during which a flow of the quenching gas through the constriction in the direction of the second arcing contact can take place (and also in the case of switching on ). During this time interval, the distance d satisfies the above-mentioned conditions at least as long as the flow of quenching gas is at least able to flow at the speed of sound. This condition is that the above-mentioned flow velocity of the arc extinguishing gas flow through the constriction in the direction of the second contact is at a maximum in this location, which is arranged inside the second contact and/or is arranged laterally on the second contact. next to the contacts.

The flow of quenching gas through the constriction in the direction of the second arcing contact can be defined such that the constriction (due to, for example, one of the two contacts) is not at least partially suppressed. In particular, therefore, the part without the arc contact is arranged in the interior of the constriction. In particular, the occurrence of the quenching gas flow in the constriction can be defined in such a way that the flow velocity of the relevant quenching gas flow within the constriction is such that it no longer increases with increasing distance d. This is basically the case at this point: when the surface (which has a minimum area) which is arranged in the interior of the extension connected to the constriction and through which the quenching gas flows, has a direction perpendicular to the axis , the area of the narrow portion near the end of the narrow portion facing the second arc contact during the extinguished state is the same (or 1.5 times or 2 times) the cross-sectional area. This comparison of the areas can further define the presence of a flow of quenching gas guided through the constriction.

The distance d is a kind of separation. The distance d is of course measured between the ends of the constriction facing one another and the second contact.

The constriction can also be referred to as a nozzle channel. It is most advantageous if the narrowing is formed lengthwise, that is to say the length of the narrowing is greater than its width. Advantageously even an aspect ratio of 1.5 times, at least 2 times or at least 2.5 times. The long nozzle constriction has a large (internal) surface area. As a result, the arc burning in the constriction can be extinguished by a large area of the nozzle material (eg PTFE), with the result that the arc is extinguished particularly reliably. Furthermore, if one of the two arcing contacts is a suppressor contact, especially long nozzle channels can generate particularly strong pressures in the heating chamber, because for the same movement speed Say, the nozzle channel for a longer time is restrained by the contact and the nozzle.

The contact separation means the separation of the physical contact between the two arcing contacts. Physical contact can be achieved, for example, by direct mutual contact of the contacts, or also by an intermediate contact (bonding contact) that brings the two arcing contacts into contact.

With regard to the length of the time interval during which the distance d satisfies the condition, i.e. lies within the distance interval, it can be stated as follows: For a typical high-power switch of the relevant form, the minimum arc time (shortest time interval, between arc burn) between about 5 ms or 7 ms to about 15 ms. The maximum arc time (the longest time interval during which the arc burns before it is extinguished) typically lies between 15 ms or 17 ms to 30 ms. The arc time interval giving the difference between the maximum and minimum arc time is typically between 10 ms and 15 ms.

The above-mentioned conditions for the distance d are advantageously fulfilled during at least 10 ms, at least 15 ms or at least 20 ms in order to ensure good flow characteristics in the heating chamber after the arc is extinguished during the largest and most important pressure drop part. The condition for d is advantageously also additionally satisfied for the duration of the arc time interval, whereby it is advantageously fulfilled during a time interval of at least 20 ms, at least 25 ms, at least 30 ms or at least 35 ms. It is particularly advantageous that the arc load can also be at least partially realized already with short arc times while the above-mentioned conditions for d are fulfilled. It is therefore particularly advantageous if the condition is fulfilled during a time interval of at least 25 ms, at least 30 ms, at least 35 ms, at least 40 ms, at least 45 ms or at least 50 ms. In order to achieve as reliable switching as possible in practically all switching situations and to prevent back arcing, conditions for longer time intervals, such as 60 ms, 80 ms or 100 ms or longer, can also be met when the insulating nozzle and the second arcing contact This can be achieved particularly well when the head moves at substantially the same speed in the same direction shortly after releasing the constriction, ie shortly after the flow of switching gas through the constriction is achieved.

If the second contact has no openings for the discharge of the quenching gas in the open switching state and is formed, for example, by a solid pin, the point of maximum flow velocity or minimum quenching gas density is located laterally on the second contact according to the invention. beside. However, if the second contact, in the open switching state, has a hole for the discharge of the quenching gas, for example formed by a hollow pin, in particular a Torx contact, then the point of maximum flow velocity is arranged laterally with respect to the axis Beside the second contact and/or inside the opening.

In particular, the location of the maximum quenching gas flow rate or the minimum quenching gas density is not arranged within the connecting path, ie not in the region between the two contacts. The point of maximum arc extinguishing gas flow rate is not arranged inside the constriction, nor is it arranged between the constriction and the second contact.

The selection of the distance d according to the invention achieves an optimization of the switching gas flow, in particular in the constriction and in the second contact region. The quenching gas flow is optimized in such a way that a particularly high withstand voltage safety is produced where particularly high dielectric loads occur. This preferred effect is achieved by the invention, since a high switching gas density can be achieved along the connecting path through the selection of the distance d according to the invention, while a lower switching gas density is achieved at the point of contact. The dielectrically less loaded locations occur on the side (or inside) of the second contact.

In a special embodiment of the invention, the distance d lies within the distance interval from the extinguishment of the arc. When the arc is extinguished and back arcing is prevented, dielectric strength is first required.

In an advantageous embodiment of the invention, the widening is substantially funnel-shaped. In particular, the extension advantageously leaves the side channel free. These side channels are used, as is known for example from DE 35 43 762 A1, for depressurizing the nozzle, especially in constricted areas. In the above-mentioned documents, there is no arc load at all by the gas heated by the arc, and there is likewise no temporary storage of the gas heated by the arc. The loading is carried out by cooled gas (compressed air). The stenosis is also very short in the above-mentioned documents and does not form a lengthwise channel.

Advantageously, an axial and radial coordinate is defined by the axis, and the narrowing is formed lengthwise. In particular, the extent of the stenosis measured along the axial coordinate is at least 1.5 times, or advantageously even at least 2 times greater than the extent of the stenosis measured along the radial coordinate.

In a further variant of the invention, the distance d is located in the distance interval at least as long as an ultrasonically induced shock wave can be generated in the switching gas flow. By maintaining the distance d inside the distance interval, the compressive strength problems due to shock waves can be greatly alleviated.

In a further embodiment of the invention, the constriction and widening have a geometry deviating from the geometry of the Laval nozzle close to the transition from the narrowing to the widening. Ultrasonic flow can occur in a Laval nozzle without shock waves. But it is the shock wave that causes the problem solved by the present invention. For example, a switch is disclosed in US 3 842 226, which has a belly-shaped nozzle comprising two necks. A neck is formed by the Laval nozzle and is responsible for causing a strong pressure drop in the nozzle belly. This is contrary to the idea of the invention, since according to the invention a high quenching gas density and a correspondingly high compressive strength can be produced.

In an advantageous embodiment of the invention, there is a relative movement of the second contact and the insulating nozzle during the breaking process, in particular a relative movement of the second contact and the extension of the insulating nozzle, wherein the speed of this relative movement is equal to the distance Periods in which d lies in the interior of the distance interval decrease at least sometimes. This is an advantageous way how it can be achieved that the second contact can remain within the distance space for a relatively long time, as long as the distance d does not remain constant during the opening process.

In an advantageous embodiment of the invention, the distance d lies within the distance interval in the end position after the disconnection process. This can be achieved, for example, by moving the second contact piece and the nozzle at substantially the same speed in the same direction at the latest from extinction of the arc.

The distance d is advantageously kept substantially constant within the distance interval. This allows optimum flow characteristics to occur during long time intervals and minimizes the influence of the damping and/or backflow characteristics on the distance d.

The method according to the invention for switching off a high-power switch filled with arc-extinguishing gas, which has a first arcing contact and a second arcing contact and has an insulating nozzle with a constriction, the method According to the scheme of the present invention, comprise the following steps:

- separating the two arcing contacts from each other, whereby an electric arc is ignited between the two arcing contacts, by means of which arc the quenching gas is heated, temporarily stored in the heating chamber;

- the quenching gas is guided along an axis from the heating chamber through the constriction by means of a quenching gas flow and into a widening connected to the narrowing, wherein the narrowing has a direction perpendicular to the axis adjacent to the widening , the cross-sectional area whose area is F;

- during this quenching gas flow, at least in the switched-on condition - in which case the quenching gas flow can flow at least locally at sonic or supersonic speed - a measured parallel to the axis, in the constriction and the second The distance d between the arcing contacts is maintained within the distance interval at least as long as the flow of arc-extinguishing gas can at least partially flow at sonic or supersonic speed;

- wherein the distance interval depends on the area F, the geometrical design of the second contact and the geometrical design of the extension, and

- wherein said distance interval is given by:

- on the one hand, corresponding to the lower distance separation limit, the cross-sectional area for the passage of the quenching gas flow at the expansion point has at least an area F, in particular an area of at least 1.5×F,

- On the other hand, corresponding to the upper distance separation limit, the minimum value of the arc-extinguishing gas density generated in the constriction or between the constriction and the second contact is greater than that in or beside the second contact. The minimum value of the arc gas density.

The method according to the invention can also be referred to as a method for switching on a current via a high-power switch.

In another embodiment, the invention can thus be formed by selecting the distance d during the extinguished state (and at least for critical time intervals) such that

d=(F/π) ^1/2 ×((1+b'cosα) ^1/2 -1)/(sinαcosα),

where for parameter b' holds: b'=b-F'/F, and where for parameter b holds:

1.4≤b≤4.5, especially

1.7≤b≤4.0, especially

2.1≤b≤3.5, and particularly advantageously

2.2≤b≤3.2.

F here is the above-known confinement cross-sectional area perpendicular to the axis (also arranged radially with respect to the axis) near the end of the constriction facing the second arcing contact during the extinguished state. In the case of a cylindrical constriction, said cross-sectional area is the cylindrical capping surface area. F' is the cross-sectional area perpendicular to the axis (also arranged radially with respect to the axis), optionally provided in the second contact piece, for the discharge of the quenching gas. And the angle α is the opening angle α of the widened portion adjoining the narrowed portion. For a second contact formed in the form of a solid pin (without outlet opening) b'=b.

When the parameter b is equal to 1, the area F through which the quenching gas flows at the end of the constriction facing the second contact is equal to the smallest area through which the quenching gas flows in the widening. In this case, this minimum area is approached by a frustoconical lateral surface area, for which the area F' may also be reached. The parameter b gives the geometric (theoretical) ratio of the lateral surface area of the frustum (if necessary also the area F') to the area F.

For b<1, the flow of quenching gas through the constriction is so low that no good and generally insufficient arc load is achieved (bad behavior during thermal switch-on). Due to wall friction losses and processing errors, and because the area actually used by the arc extinguishing gas flow is smaller than the above-mentioned frustum side surface area (including the discharge hole area if necessary) due to the direction deflection of the arc extinguishing gas flow after it comes out of the narrow part , for values of b between 1 and approximately 1.4, satisfactory quenching gas flows and arc charges have not been achieved in practice. This is practically achievable only from b ≈ 1.4 and for larger b. For values b of less than 1.4 and less than 1, the range of maximum flow rates is also provided next to and/or within the second contact. In practice, b can be taken to be at least 2 or at least 2.5.

If the parameter b is chosen to be greater than about 4.5 or 5, a relatively low quenching gas pressure and a relatively low quenching gas density are generally produced near the axis between the constriction and the second contact. In this case, the maximum flow velocity range is provided there and not next to the second contact and/or within the second contact and correspondingly detrimental to the dielectric strength of the connecting path section.

Approximately, the distance d can also be selected according to the following inequality in the case of F'≈0:

0.5×(F/π) ^1/2 /tanα'≤d≤1.2×(F/π) ^1/2 /tanα'+0.55×D, especially

0.8×(F/π) ^1/2 /tanα'≤d≤1.0×(F/π) ¹ /2/tanα'+0.45×D.

Wherein the angle α' is equal to the opening angle α, as long as α≤45°, and α'=45° for α>45°.

Through the above-mentioned selection of the distance d as a function of the cross-sectional area, the above-mentioned flow velocity conditions are met for common switching geometries. When the distance d can be kept within a narrow given range for d, or the parameter b can be kept within a narrow given range for b, it can be better ensured that the preferred quenching gas flow is maintained.

For the approximate calculation of the area, a cylindrical second contact piece is assumed, which has no rounded corners or the like at the ends. Correspondingly, for other contacts, for example rounded corners, either a slightly different formula is used, or the distance d does not start from the contact end, but rather a larger distance.

Furthermore, the approximate calculation of the area presupposes that the cross-sectional area (or diameter) of the second contact piece is substantially equal to the corresponding dimension of the constriction. In particular if the second contact is not a suppressor contact, other dimensions are also possible, so correspondingly modified formulas are used if necessary.

As long as the widening point adjoining the stenosis firstly has a first opening angle α and then subsequently has another opening angle α which is greater or smaller than the first opening angle α (stepped widening point) , then a corresponding mean opening angle α is used in the formula given for the distance d. Even in the case of curved or undulating widenings, a corresponding mean opening angle α is used.

The high-power switch can advantageously have a constriction which essentially consists of a cylinder. In this case, the distance d during the extinguished state is advantageously selected such that the following applies:

d＝D×((1+b'·cosα) ^1/2 -1)/(2·sinα·cosα)

where for parameter b' applies: b'=b-F'/F, and where for parameter b:

1.4≤b≤4.5, especially

1.7≤b≤4.0, especially

2.1≤b≤3.5, and particularly advantageously

2.2≤b≤3.2.

Here, the diameter D of the cylinder is close to the end of the cylinder facing the second arcing contact during the extinguished state. F' is the area of the cross-section of the opening, which is arranged perpendicularly to the axis (i.e. is arranged radially relative to the axis), and which is optionally located in the second contact, for the discharge of the quenching gas. The angle α is, in turn, the opening angle α of the widening point adjoining the narrowing point. For a second contact made of a solid pin (without an exit hole), b'=b.

The distance d can also be selected approximately in the case of F'≈0 according to the following inequality:

0.25×D/tanα’≤d≤0.6×D/tanα’+0.55×D, especially

0.4×D/tanα’≤d≤0.5×D/tanα’+0.45×D

In this case, the angle α' is equal to the opening angle α as long as α ≤ 45°, and α' = 45° for α > 45°.

Due to the above-mentioned selection of the distance d as a function of the diameter of the cylinder, the density, pressure or flow rate conditions according to the invention are generally met for common switching geometries. When the distance d can be kept within a narrow given range for d, or the parameter b can be kept within a narrow given range for b, it can be better ensured that a favorable flow of quenching gas is maintained.

In an advantageous embodiment of the subject matter of the invention, the constriction can be at least partially suppressed by one of the two arcing contacts. This arcing contact is called a suppressor contact. During the extinguished state, in this case the constriction is no longer at least partially restrained by the restraint contact. The first and/or second arcing contact may act as a suppression contact.

In another possible embodiment, the distance from the second contact to the narrow part is constant. In this case, the first contact moves relative to the constriction.

In a further advantageous embodiment of the subject matter of the invention, at least one arcing contact of the two arcing contacts is driven by a drive mechanism and moved along an axis. It is particularly advantageous if the two arcing contacts are displaceable and the first drive mechanism is used to drive the first arcing contact and the second drive mechanism is used to drive the second arcing contact. In this case, the second drive mechanism can advantageously be realized by a transmission driven by the first drive mechanism.

The drive is advantageously designed in such a way that the direction of movement of at least one arcing contact is switched from a movement in the opposite direction to a movement in the same direction of this arcing contact and the insulating nozzle. Advantageously, this reversal of the direction of movement occurs during the flow of switching gas through a constriction, in particular if the constriction is not at least partially suppressed by one of the contacts.

A movable intermediate contact can be arranged movably between the two arcing contacts, whereby the two arcing contacts can be fixed.

In a further advantageous embodiment of the subject matter of the invention, the constriction is connected to the heating chamber via a channel, in particular via a ring channel.

The second contact is advantageously designed in the shape of a pin. It is also possible to design it as a solid pin or as a hollow pin. In particular, it can also be formed by tulip contacts. The second contact can have openings for escaping the quenching gas in the open switching state. Advantageously, the first and the second arcing contact can be realized as a contact pair consisting of a tulip contact and a contact pin.

In another advantageous embodiment, during the extinguished state, or at least so long that the distance d lies within the distance interval, the insulating nozzle and the second contact move in the same direction. This advantageously also applies during the extinguished state for the ratio v1/v2 of the velocity v1 of the insulating nozzle to the velocity v2 of the second contact: 0.4≤v1/v2≤1.2, in particular 0.75≤v1/v2≤1.15. It is particularly advantageous for 0.9≦v1/v2≦1.08 or v1/v2≈1 to apply during the extinguished state. The insulating nozzle and the second arcing contact advantageously move in the same direction at substantially the same velocity different from zero during the extinguished state.

By means of a velocity ratio v1/v2 of approx. 1:1 after the direction of movement has been reversed, it is possible to reduce the load on the damping device or to use a simpler damping device, since longer damping strokes (longer paths, in The movement is braked during this path). Because after reaching a sufficient (generally maximum) distance between the two arcing contacts in advance, the braking of the contacts can already start, because the contact distance is transmitted by 1:1. The ratio remains constant. For speed ratios v1/v2 close to 1, the same works in principle, but in this case a small change in the contact distance occurs.

The high-power switch can be constructed in the form of a self-pressurized gas switch. In this case, the volume of the heating chamber is constant. High-power switches can also be designed in the form of snubber switches. In this case, the heating chamber is also a compression chamber, the volume of which decreases during the disconnection process in order to achieve a better arc blowing due to the additional pressure. The high-power switch can also have a heating chamber, preferably with a constant volume, and an additional compression chamber, wherein at least the volume of the compression chamber decreases during the switching-off process. Advantageously there is a valve between the compression chamber and the heating chamber.

The two arcing contacts are advantageously arranged coaxially to one another.

The arcing contact can also be a rated current contact at the same time. Advantageously, however, a separate rated current contact is additionally provided for the arc contact. Generally, for the disconnection process, the nominal current contacts are first separated from one another, so that the current to be interrupted is switched over the arcing contacts. The arcing contacts are then separated under conditions that ignite the arc.

Advantageously, one of the two arcing contacts, in particular the first arcing contact, can have a seat for receiving the other arcing contact, which is advantageously designed as a pin in the closed switching state, And for the venting of the arc-extinguishing gas in the open switching state. In particular, it is possible for the arc contact to be formed as a tulip contact with a plurality of contact fingers.

It is advantageous if the second arcing contact is pin-shaped and movable, while the first contact has a bore for receiving the second contact and is movable or immovable. Said insulating nozzle is advantageously connected rigidly to the first contact.

A high-power switch in the sense of the present application is in particular a switch which is installed for a rated voltage of at least approximately 72 kV. The high power switch can have one or more switching chambers.

Further preferred embodiments and advantages are given by the dependent claims and the figures.

Description of drawings

The subject matter of the invention is described in more detail below with the aid of a preferred exemplary embodiment shown in the drawing. In the attached picture:

FIG. 1 shows a detail of a power switch according to the invention in the open state in a cross-sectional view,

2 shows a detail of a power switch according to the invention with two movable arcing contacts in the open and closed state in a cross-sectional view and a top view of the actuator,

Figure 3 graphically shows the ratio of the distance d to the diameter of the stenosis D for different parameters b' according to the relationship as a function of the opening angle α,

Figures 4-8 graphically show the simulation calculations of the quenching gas flow at different distances d, which are represented by isobars.

The reference symbols used in the figures and their meanings are listed in summary in the list of reference symbols. In principle, identical or functionally identical components are provided with the same reference symbols in the figures. Components that are not essential for understanding the invention are partially not shown. The examples are used by way of example for the subject matter of the invention and have no restrictive effect.

Detailed ways

1 schematically shows in section a part of a high-power switch according to the invention which can be filled with an quenching gas such as SF ₆ or a mixture of N ₂ and SF ₆ . The switch has a first arcing contact 1, which is formed as a tulip contact. The first arcing contact 1 is surrounded by an auxiliary nozzle 13 , which together with the insulating nozzle 5 forms a channel 7 designed as a ring channel 7 . The insulating nozzle forms an essentially cylindrical constriction 6 for guiding the quenching gas flow. A diameter-widening region 21 with an opening angle α≈45° adjoins the narrowing point 6 . The channel 7 connects the constriction 6 to a heating chamber 11 for temporarily storing the quenching gas. On the side of the constriction 6 facing away from the first contact 1 , a pin-shaped second arcing contact 2 is arranged. Advantageously, the switch has exactly two arcing contacts.

The diameter of the cylinder at the stenosis is denoted by D. The distance from the second contact 2 to the constriction 6 is denoted by d. Here d≈(0.7±0.1)×D. The end of the second contact 2 facing the constriction 6 is arranged in a region 21 adjoining the constriction 6 that expands diametrically relative to the constriction 6 . The diameter of this area 21 first increases significantly, then remains essentially constant, and then increases slightly. Depending on the shape of the insulating nozzle 5, it is possible to arrange the end of the second contact 2 facing the constriction 6 in a section with a more or less strongly increased diameter, or also in the region 21 of the insulating nozzle 5. At a substantially constant diameter, the arc extinguishing gas density or arc extinguishing gas pressure is at a minimum in point 20, which is arranged next to the second arcing contact 2 (or the flow rate of the arc extinguishing gas flow is at point 20, if the conditions are met Maximum, this location is arranged next to the second arc contact 2).

Unlike that shown in FIG. 1 , such a location 20 is generally close to the second contact (see also FIGS. 4 to 8 below).

Advantageously, the second contact piece 2 is likewise substantially cylindrical. The diameter of each cylinder (nose or second contact) does not have to be completely constant, but can vary slightly. Deviations from a circular cross-section may, for example, be oval cross-sections.

Said constriction 6 (or second contact 2 ) may advantageously have another substantially prismatic shape and be referred to as "substantially cylindrical". The diameter D is considered to be the corresponding radial dimension of the stenosis. In particular, a good precision of the diameter of a circle which has the same area as the constriction next to the second contact 2 is possible. It is also not necessary that the diameter of a cylinder or the radial dimension of a prism be exactly constant. The parameter that is important for determining d is the radial dimension of the cylinder or prism at the end facing the second contact 2 . Such constriction shapes are also included in the concept of "substantially cylindrical".

The high-power switch is substantially rotationally symmetrical with an axis of symmetry A. Axial directions z1 and z2 extending parallel to the axis A, and a radial direction perpendicular thereto, along which the arcing contacts move, are thus defined.

The quenching gas flow is indicated by a dotted line with an arrow indicating the flow direction. The different splits of the quenching gas flow are indicated by s1 to s5 . s1 denotes the branch flow from the heating chamber to the connection path. s1 is divided into s2 and s3. s2 extends in the direction of the first contact 1 and thus in the direction z1. s3 extends within the constriction 6 in the direction of the second contact 2 and thus in the direction z2. Since the region 21 has a larger diameter than the constriction 6 and the pin contact 2 is arranged along the axis A, the partial flow s4 has a substantial radially outwardly directed component. The branching at the side of the second contact 2 is indicated by s5. Depending on the selection of the distance d shown in FIG. 1 , the point indicated at 20 with the minimum quenching gas density, minimum quenching gas pressure or maximum flow velocity is located at the point of the partial flow s5 . At the locations s3 (inside the constriction 6) and s4 (between the constriction 6 and the second contact 2), the arc extinguishing gas density is not less (and advantageously greater) (radially) than at the second contact 2 The arc extinguishing gas density at the side (at location s5 ) and the flow velocity is not greater (and advantageously smaller) (radially) than the flow velocity at the side of the second contact 2 (at location s5 ). Advantageously, the quenching gas has a higher density at point s2 than at point 20 or a lower flow rate than at point 20 .

If the second contact 2 is formed as a hollow pin or a Torx contact, there is also a further branch which runs along z2 inside the second contact 2 .

The open state of the high power switch is shown in FIG. 1 : there is no physical contact between the two contacts 1 , 2 . The high power switch is shown exactly during the time interval called the extinguished state. This defines the extinguished state, which is located after the contacts have separated and a flow of switching gas s3 is generated through the constriction in the direction of the second contact 2 . While the constriction 6 is at least partially suppressed by the second contact 2 , called the suppression contact, there is no (notably) flow of quenching gas through the constriction 6 . According to the invention, a point 20 with a minimum quenching gas density, minimum quenching gas pressure or maximum flow velocity is arranged laterally beside second contact 2 in direction z2.

The arc burning between the two contacts 1 , 2 after separation of the contacts is not shown in FIG. 1 .

2 schematically shows a detail of a power switch according to the invention with two movable arcing contacts 1 , 2 in the open state (lower diagram) and in the closed state (top diagram) in a cross-sectional view. The transmission 3 is shown schematically in plan view on the right side of the figure. The first arcing contact 1 is driven by a drive mechanism not shown. Suitable drives may be, for example, electric drives or spring-energy drives.

The second arc contact 2 is driven by a second drive mechanism 3 via a transmission 3 driven by the drive mechanism. In the closed state, the two arcing contacts 1 , 2 are in contact with each other. In addition, rated current contacts (not shown) can also be provided.

The first contact 1 is rigidly connected to the insulating nozzle 5 and to the auxiliary nozzle 13 . The insulating nozzle 5 has a constriction 6 which is substantially cylindrical and has a diameter D. FIG. The constriction 6 is connected to the heating chamber 11 via the ring channel 7 . A compression chamber 10 is connected via a valve 12 to the heating chamber. The volume of the heating chamber can be varied by the piston 15, which is advantageously fixed.

During the breaking process for interrupting the current flow through the high-power switch, the first arcing contact 1 as well as the insulating nozzle 5 , the auxiliary nozzle 13 and the valve 12 are additionally moved in the direction z1 . By selecting the delay, the second contact 2 is moved in direction z2. The mass to be moved directly by the drive mechanism is larger than the mass to be moved by the transmission 3 . Acceleration of the second contact 2 can be expected until shortly before reaching the maximum speed v1. After the first contact 1 has reached its maximum speed, it essentially maintains this speed until the braking process at the end of the opening process.

The volume of the compression chamber can be reduced by the stationary piston 15 and the valve 12 enables the flow of quenching gas into the heating chamber 10 . During the high or maximum relative speed v12 , contact separation occurs when the arc 4 is ignited. Contact separation can occur before or after (a few milliseconds) the maximum relative velocity is reached.

The arc 4 heats the quenching gas, which was originally at room temperature (300 K), and extinguishes the combustion material from the insulating nozzle 5 in the constriction 6 . The temperature of the quenching gas is brought to the order of about 30000K directly on the arc. In this way, an overpressure is generated in the heating chamber 11 by means of the ring channel 7 , which is generally between 10 bar and 60 bar. The temperature of the quenching gas in the heating chamber 11 is generally first of the order of 2000 K (in the T100a case). Valve 12 is closed due to a predeterminable pressure difference between heating chamber 11 and compression chamber 10 via valve 12 , for example, if there is a greater pressure in heating chamber 11 than in compression chamber 10 . The quenching gas which subsequently flows from the heating chamber 11 and optionally also from the compression chamber 10 through the heating chamber 11 and then via the ring channel 7 into the connecting path section arranged between the two contacts 1, 2 is generally still Has a temperature of 1000K to 2000K and is used to extinguish the arc 4 .

After the end of the second arcing contact 2 facing the first arcing contact 1 has traveled at maximum speed v2 over most of the length of the constriction 6 , v2 decreases again. The second contact 2 enters the rest state and, after opening the constriction 6 , moves in the direction z1 and thus parallel (in the same direction) to the first contact 1 . Shortly after this movement reversal, the second contact 2 reaches the same speed as the first contact 1 .

As long as the constriction 6 is no longer at least partially held back by the second contact 2, the quenching gas passes through the ring channel 7 not only through the tulip-shaped first contact 1 (in direction z1), but also through the constriction 6 and in the pin-shaped Next to the second contact 2 (in direction z2) discharge.

FIG. 1 can be used as an explanation of the current state of the high-power switch according to FIG. 2 for the current-through characteristic.

The distance d between the contact 2 of the second pin-shaped structure and the constriction 6 can be kept substantially constant by the substantially 1:1 speed ratio v1/v2 in the same direction of movement of the second contact and the insulating nozzle. This distance d is selected in such a way that when the quenching gas flows through the constriction 6 to the suppression contact 2 (in direction z2), the maximum flow velocity is located laterally next to the suppression contact 2, or at least not on both sides. On the section between arcing contacts 1 and 2 (or next to this section). A particularly effective arc load is thereby achieved and re-ignition of the arc is effectively suppressed. The distance d is chosen as d≈(0.7±0.2)×D, where D is the diameter of the stenosis 6 (at its z2-side end).

If the speed ratio v1/v2 of 1:1 is preset via the transmission 3, then when the switch is attenuated, i.e. the contacts 1, 2 are braked by the damping mechanism, the distance d and thus also the corresponding flow ratio. Towards the end of the disconnection process, on the one hand, a backflow (opposite direction of movement) of first contact 1 often results due to the pressure ratio in heating chamber 11 and/or compression chamber 10 . Even with this backflow, the distance d does not change when a speed ratio v1/v2 of 1:1 is selected. As long as the preferred flow ratio is maintained until the end of the breaking movement, a reliable arc extinguishing is thus ensured in the absence of flashback. With the speed ratio v1/v2 of 1:1, the distance between the two contacts 1 and 2 is also kept constant, which keeps the electric field distribution constant.

Through the speed ratio v1/v2 after the opposite direction of movement, it is possible to reduce the load on the damping device that brakes the movement of the contact, or to use a simpler damping device, because a longer damping stroke can be specified ( longer distances during which the braking movement takes place). This is because after a sufficient (generally almost maximum) distance between the arcing contacts has been reached in advance, the braking of the contacts takes place already, since the contact distance is kept constant by the gear ratio of 1:1. For a speed ratio v1/v2 of almost 1, the same is valid in principle, but a small change in the contact distance occurs here.

By reducing the velocity v2 of the second contact 2 at the end of the opening movement, the load on the damping device can be reduced, since less movement energy has to be absorbed.

The auxiliary nozzle 13 can also be understood as an insulating nozzle with a constriction (if the auxiliary nozzle 13 is configured accordingly), wherein the distance between the first contact 1 and this auxiliary nozzle constriction is selected according to the invention in such a way that The arc extinguishing gas density of the arc extinguishing gas flow extending in the direction z1 is the smallest at a point, or the flow velocity of the arc extinguishing gas flow extending in the direction z1 is the largest at a point, which is relative to The axis A is arranged beside the first arcing contact 1 or inside the first arcing contact 1 .

As shown in the right part of FIG. 2 (in plan view), a lever 8 is rotatably mounted on the second contact piece 2 at a first end via a pin 16 . At the second end of the lever 8 , the lever 8 is mounted rotatably via a pin 17 on the side leg of the toggle lever 9 . The second leg of the toggle lever 9 is guided in a linkage plate 14 via a pin 18 . The toggle lever 9 is rotatably mounted via a stationary pin 19 , for example fixed to the housing of the high-power switch. As indicated by the line of action W, the movement of the connecting rod plate 14 is coupled (preferably rigidly) to the movement of the first contact piece 1 .

The movement of the second contactor 2 is also controlled by a lever mechanism through the link plate 14 connected to the drive mechanism. The transmission 3 converts a constant speed (drive mechanism) linear motion into a motion in the opposite direction of motion. By suitable selection of the lever length and angle, a desired speed profile can be selected for the second contact 2 .

As shown in FIG. 1 , the transmission 3 can be constructed symmetrically, which leads to a more favorable force distribution and greater stability.

The velocity v1 of the insulating nozzle 5 and the first contact 1 can be generally between 3m/s and 10m/s, for example 5m/s, after the start of acceleration. The maximum velocity v2 of the second contact 2 can be between 12m/s and 20m/s, for example 15m/s. The maximum velocity ratio v1/v2 (for the opposite movement) may be between 1:2.4 and 1:3.5, eg 1:3. Thereby can correspondingly reach general 13m/s, 15m/s, 17m/s, 19m/s and greater relative velocity v12, they can realize quick release pin 6, and by providing large extinction within a short time arc gas pressure to achieve effective arc loading. If the constriction has a greater length (axial extension), then a very large insulating nozzle surface can be placed under the arc in this way, whereby a large amount of material can be evaporated from the insulating nozzle, whereby Achieving an effective arc load. In particular, the length of the stenosis can be greater than 40 mm, preferably greater than 50 mm and greater than 60 mm. Larger distances between contacts 1 and 2 (insulation path) can also be achieved in a very short time.

A corresponding high-power switch can be used for rated short-circuit currents exceeding 40kA or 50kA at rated voltages exceeding 170kV or 200kV.

Figure 3 shows the graphical relationship of the equation:

d=D×((1+b'·cosα) ^1/2 -1)/(2·sinα·cosα),

Among them, it represents the relationship between d/D and the opening angle α (alpha). Corresponding curves are given for the parameters b'=1, b'=2, b'=3, b'=4 and b'=5. A suitable (fluid-optimized) ratio d/D for an approximately cylindrical stenosis of diameter D can be obtained from the curve (see FIG. 1 ). These ratios lie in the range of approximately b=1.4 to b=4.5, where b'=b−F'/F, and F' is perpendicular to the axis, possibly located in the second contact 2 for the discharge of the quenching gas The cross-sectional area of the hole. F is the cross-sectional area perpendicular to the axis of the constriction 6 close to the end of the constriction 6 facing the second arcing contact 2 during the extinguished state (see FIGS. 1 and 2 ). As shown in Figures 1 and 2, for a second contact 2 without a discharge hole, F'=0 and b'=b. The value d/D≈0.7 for α≈45° can also be obtained from the curve, which is shown in FIG. 1 .

The maximum relative speed v _{12 , max of the contacts 1 , 2} is advantageously selected for such a switch to be at least 40%, in particular at least 60% and even at least 80% greater than the speed required for a capacity switch. Advantageously, the switching chamber is designed in such a way that when it is installed in a single-chamber high-power switch, for the maximum relative speed v _{12, max} of the two arcing contacts 1, 2 relative to each other during the breaking process, the : v _{12, max} ≥k'×U _N ·p·f/(E _krit ·p ₀ ), where U _N is the rated voltage of the high-power switch in kV; p is the pole coefficient of the high-power switch (dimensionless ), E _krit is the field strength used for arc extinguishing gas unloading, the unit is Kv/(bar m), p ₀ is the full pressure of the arc extinguishing gas, the unit is bar (typical value is 4 bar or 6 bar, the general total is between 1 bar and 10 bar), and f is the high-voltage network frequency, the unit is Hz, and the high-power switch is designed for this network frequency. v _{12, the unit of max} is m/s. The coefficient k' is 23, advantageously 27, preferably 31. In the case of high-power switches with more than one switching chamber, a further factor is added which takes into account the control process of the high-power switch.

As a result, very large arc sections can be generated in a very short time. During relatively long time intervals, a large surface, in particular the entire inner surface of the constriction, can be used for generating (evaporating) the material which extinguishes the arc. This produces a large amount of arc-extinguishing material, so that an effective arc load is achieved. Due to the very rapid relative movement, such a large amount of arc-extinguishing material can already be generated in a very short time, so that a very high arc-extinguishing gas pressure can be generated, which can be generated very quickly after the separation of the contacts. This makes it possible to achieve very strong arc loads and thus very reliable switching, even in the case of high short-circuit currents.

4 to 8 show graphs of simulated calculations for the switching gas flow at different distances d. The simulation calculations are based on the theory of fully compressible gas flows. The figures show isobars, ie lines of equal pressure. Only the section of the upper half of the rotationally symmetric problem (axis of rotation A) is shown. Common parameters for all simulations are: the quenching gas is SF ₆ at room temperature (300K); the filling pressure (static pressure) is p ₀ =6 bar; The pressure in p _H ) was 20 bar. The pressure ratio p ₀ /p _H =6/20=0.3 is therefore. This is significantly less than the Laval-to-pressure ratio for SF ₆ , which is about 0.59. A supersonic flow thus occurs at least locally. The parameter that differs in the simulations of FIGS. 4 to 8 is the distance d.

Shock waves ("shock bottles") can be seen in all of Figures 4-8, and are particularly evident in Figures 6-8.

The second contact 2 is arranged at the bottom left in FIGS. 4-8 ; it is designed as a solid pin and has rounded ends. The stenosis 6 is arranged at the bottom right. The quenching gas flow s3 , symbolized by an arrow, flows through the elongated constriction 6 . The calculated nozzle geometry cannot be fully realized in the expanded region 21 since it has an opening angle of 90°. The opening angle α is generally between 30° and 60°. D is the diameter of the stenosis, which is chosen as 20mm. d is the distance between the second contact and the end of the narrow portion 6 facing the second contact during the extinguished state.

The minimum quenching gas density, the minimum quenching gas pressure or the maximum flow rate between the second contact piece and the constriction or in the constriction is denoted by ρ1, p1, M1. The minimum quenching gas density, the minimum quenching gas pressure or the maximum flow rate next to the second contact is indicated by ρ2, p2, M2. In Figures 4-8 the dotted line shown for the purpose of representing the distance d can be regarded as between the position "beside the second contact" and the position "between the second contact and the narrow position or in the narrow position" the border between.

FIG. 4 shows the case of d=0.2×D. In this case, there is a region 20 on the side of the second contact in which the pressure p2 (p2=1 bar) is significantly lower than the minimum pressure p1 in the connecting path (p1=19 bar). The corresponding local flow velocities are M2 = Mach 2.2 and M1 = Mach 0.9. The maximum flow velocity M2 next to the contact is therefore significantly greater than the maximum flow velocity M1 in front of the contact.

d is also sufficiently small for a good compressive strength to be achieved according to the invention. However, since d is only 0.2×D, the cross-sectional area available for the quenching gas flow in the widening region is only approximately as large as the cross-sectional area occurring in the narrowing region (F=πD ² /4). Compare this to FIG. 3 with the curves for b′=1 at α≈90°: accordingly at d≈0.25 an area of the same size occurs, but only for non-rounded cylindrical contacts.

A larger distance d is therefore desirable to achieve more severe loads.

FIG. 5 shows the case of d=0.6×D. Even in this case there is also a region 20 on the side of the second contact in which the pressure p2 (p2=1.3 bar) is significantly lower than the minimum pressure p1 in the connection path (p1≈4.2 bar; at axis A on p1 = 8.8 bar). The corresponding local flow velocities are M2 = Mach 2.2 and M1 = Mach 1.5 (also on axis A). The maximum flow velocity M2 next to the contact is therefore significantly greater than the maximum flow velocity M1 in front of the contact.

d is also sufficiently small to achieve a good compressive strength according to the invention. Furthermore, since d=0.6×D, given the existing nozzle geometry, the cross-sectional area available for the quenching gas flow in the widened area is significantly larger than the cross-sectional area occurring in the narrowed area, thus ensuring a strong extinguishing arc load.

FIG. 6 shows the case of d=0.9×D. Even in this case there is also a point 20 on the side of the second contact in which the pressure p2 (p2=2.1 bar) is significantly lower than the minimum pressure p1 in the connection path (p1≈3.3 bar; on axis A p1 = 4.3 bar). The corresponding local flow velocities are M2 = Mach 1.9 ≈ 245 m/s and M1 = Mach 1.9 ≈ 240 m/s (on axis A). The temperature in the point 20 , ie for p2 and M2 , is greater than the temperature in the region p1 , M1 ; and the local sound velocity in Mach is given as a function of the temperature. The maximum flow velocity M2 next to the contact is therefore still slightly greater than the maximum flow velocity M1 in front of the contact.

d is also sufficiently small to achieve a good compressive strength according to the invention. Furthermore, since d=0.9×D, the cross-sectional area available for the quenching gas flow in the widened area is significantly larger than the cross-sectional area present in the narrowed area, thus ensuring a strong arc-extinguishing load.

FIG. 7 shows the case of d=1.5×D. In this case, there is no longer any point on the side of the second contact in which the pressure p2 (p2=2.0 bar) is lower than the minimum pressure p1 (p1=1.9 bar) in the connection path. The corresponding local flow velocities are M2 = Mach 1.9 and M1 = Mach 2.2. The maximum flow velocity M2 next to the contact is therefore smaller than the maximum flow velocity M1 in front of the contact.

Although d=1.5×D makes the cross-sectional area available for the quenching gas flow significantly larger in the expansion than in the constriction, thus ensuring a strong extinguishing load; the distance d is too large to make it possible A good compressive strength according to the invention is ensured.

FIG. 8 shows the case of d=2.0×D. In this case there is no longer any point on the side of the second contact in which the pressure p2 (p2=2.1 bar) is lower than the minimum pressure p1 in the connection path (p1=1.6 bar). The corresponding local flow velocities are M2 = Mach 1.8 and M1 = Mach 2.4. The maximum flow velocity M2 next to the contact is therefore smaller than the maximum flow velocity M1 in front of the contact.

Although d=2.0×D makes the cross-sectional area available for the quenching gas flow significantly larger in the widening than in the narrowing, thus ensuring a strong extinguishing load; the distance d is too large to be possible A good compressive strength according to the invention is ensured.

In summary Figures 4-6 show the case of (d=0.2×D, d=0.6×D, d=0.9×D), in which the distance d is smaller than the upper limit of the distance interval, where this upper limit is given by such that The minimum value p1 of the quenching gas pressure generated in the constriction 6 or between the constriction 6 and the second contact 2 is greater than the minimum value p2 of the quenching gas pressure generated in or next to the second contact 2 .

In the formula with the corresponding arc extinguishing gas density:

Figures 4-6 (d=0.2×D, d=0.6×D, d=0.9×D) show situations in which the distance d is smaller than the upper limit of the distance interval, where this upper limit is given by such that The minimum value ρ ₁ of the quenching gas density which occurs in the constriction 6 or between the constriction 6 and the second contact 2 is greater than the minimum value of the quenching gas density which occurs in or next to the second contact 2 ρ ₂ .

In the formula with the corresponding arc extinguishing gas flow rate:

Figures 4-6 (d=0.2×D, d=0.6×D, d=0.9×D) illustrate the case where the distance d is smaller than the upper limit of the distance interval, where this upper limit is given by, Make the maximum value M1 of the arc extinguishing gas flow rate generated in the narrow part 6 or between the narrow part 6 and the second contact 2 smaller than the maximum value of the arc extinguishing gas flow rate generated in or beside the second contact 2 M2.

On the other hand, FIGS. 5-8 show (d=0.6×D, d=0.9×D, d=1.5×D, d=2.0×D) the case where the distance d is greater than the lower limit of the distance interval, This lower limit is given here by the fact that the cross-sectional area for the switching gas flow in the widening 21 is at least as large as the cross-sectional area of the constriction (closer to the widening).

Therefore, in the case of d=0.6×D ( FIG. 5 ) d=0.9×D ( FIG. 6 ), the distance d is selected according to the invention and has the advantages according to the invention, as long as the distance d remains at The distance interval is inside. Whereas the case of d=0.2×D ( FIG. 4 ) does not allow a sufficiently intense discharge of the quenching gas and thus shows a position of the second contact which is not occupied according to the invention during the critical time interval for back arcing. Location. In the case of d=1.5×D (Fig. 7) and d=2.0×D (Fig. 8), the density and arc extinguishing gas pressure are also smaller on the connecting path than next to the contact, so for back arcing According to the invention, this position is also not occupied during critical time intervals, since otherwise there would be a risk of back arcing.

In the case of a suitable distance d for the invention, said location 20 is arranged next to the second contact in which the minimum local quenching gas density (or the minimum local quenching gas pressure, or the maximum flow rate of the quenching gas ), which (or they) occur in the stenosis 6 or in the dilation 21 .

List of reference signs

1 contact, first arcing contact

2 contacts, second arc contact, suppression-contact

3 Second drive mechanism, transmission

4 arc

5 nozzles, insulated nozzles

6 Stenosis

7 channels, ring channel

8 leverage

9 toggle lever

10 compression chamber

11 heating chamber

12 valves

13 auxiliary nozzle

14 connecting rod, connecting rod plate

15 pistons

16, 17, 18 pins, rotatable bearings

19 Fixed pin, rotatable bearing

20 position, the position of the minimum arc extinguishing gas pressure, the minimum arc extinguishing gas density

Location, the location of the maximum flow rate

21 site, extended site, site that expands in radius

A axis, axis of symmetry

b, b' parameters

d distance

D diameter, radial dimension

F face, area

M1 flow rate

M2 flow rate

p pressure

p ₀ filling pressure, static pressure, background pressure

p1 pressure, the minimum value of the arc extinguishing gas pressure occurring at the constriction or between the constriction and the second contact; the minimum arc extinguishing gas present at the constriction or between the constriction and the second contact pressure

p2 pressure, the minimum value of the arc extinguishing gas pressure present in or next to the second contact; the minimum arc extinguishing gas pressure present in or next to the second contact

p _H Fill gas pressure in heating chamber

s1, s2, s3, s4, s5 Arc extinguishing gas - split flow

v1 speed of insulating nozzle

v2 Speed of the second contact

v12 relative speed

W line of action

z1 direction

z2 direction

α opening angle

α' angle

_ρ1 density, the minimum value of the arc extinguishing gas density occurring in the constriction or between the constriction and the second contact; the minimum arc extinguishing gas present at the constriction or between the constriction and the second contact density

_ρ2 density, the arc extinguishing gas density present in or next to the second contact; the minimum arc extinguishing gas density present in or next to the second contact

Claims (13)

1. high power switch, it can be full of by a kind of arc extinguishing gases,

-have one first arc contact (1) and one second arc contact (2),

-have the electric arc (4) that may between described arc contact (1,2), burn,

-have one to be used for the temporary heating chamber (11) that passes through the arc extinguishing gases of electric arc (4) heating, and

-having an insulation nozzle (5), it has a narrow positions (6) that is connected with heating chamber (11) in order to make arc extinguishing gases stream (s3) along an axis (A) guiding, is connecting an expansion position (21) thereon,

-wherein this narrow positions (6) near expansion position (21) have one perpendicular to axis (A), area is the cross-sectional area of F,

It is characterized in that,

-pass during the later disconnection process of contact separation, on arc extinguishing gases stream (s3) can the direction (z2) in second arc contact (2) narrow positions (6) extinguish state during, at least under the connection situation, arc extinguishing gases flows (s3 in this case, s4) can flow with the velocity of sound or supersonic speed at least partly

-one parallels to the axis (A) measure, between narrow positions (6) and second arc contact (2), flow (s3 with making arc extinguishing gases at least apart from d, s4) at least partly can with the velocity of sound or supersonic speed flow the same position (21) that is positioned at a geometry that depends on area F, second contact (2) and expansion for a long time geometry distance at interval in

-wherein provide distance thus at interval,

-on the one hand, apart from the interval limit, have the area of area F, especially at least 1.5 * F at least for arc extinguishing gases stream (s3) through-flow cross-sectional area at expansion position (21) corresponding to down,

-on the other hand, corresponding to the last distance interval limit, at the arc extinguishing gases density (ρ of narrow positions (6) or plug generation between narrow positions (6) and second contact (2) ₁) minimum value greater than in second contact (2) the inside or the arc extinguishing gases density (ρ that the next door produced ₂) minimum value.

2. high power switch as claimed in claim 1, wherein said extinguishing from electric arc (4) apart from d begins just to be positioned at described distance inside at interval.

3. as each described high power switch in the above-mentioned claim, basic infundibulate ground, wherein said expansion position (21) constitutes, and especially vacates lateral access.

4. as each described high power switch in the above-mentioned claim, wherein by axis (A) definition one an axial and radial coordinate, and wherein said narrow positions (6) lengthways constitutes, and wherein especially along at least 1.5 times of the measured narrow positions of axial coordinate (6) expandable parts to along the measured narrow positions of radial coordinate (6) expandable part.

5. each described high power switch as in the above-mentioned claim, wherein said apart from d at least with (s3 can produce that the ultrasonic shock wave that causes is the same to be arranged in described distance at interval for a long time in s4) at arc extinguishing gases stream.

6. as each described high power switch in the above-mentioned claim, wherein said narrow positions (6) and expansion position (21) have a kind of geometry that departs from Bearing score ear nozzle geometry near the transition portion from narrow positions (6) to expansion position (21).

7. as each described high power switch in the above-mentioned claim, wherein during the disconnection process, exist the relative motion of second contact (2) and insulation nozzle (5), especially the relative motion at the expansion position (21) of second contact (2) and insulation nozzle (5) reduces when wherein the speed of this relative motion (v12) has at least during distance d is positioned at inside, distance interval.

8. each described high power switch as in the above-mentioned claim, wherein said to be positioned at distance after the disconnection process apart from d in a terminal location inner at interval.

9. as each described high power switch in the above-mentioned claim, it is characterized in that described narrow positions (6) is by described two arc contacts (1; 2) arc contact in-it is called as inhibition-contact (2)-suppress at least in part, and described narrow positions (6) no longer suppresses by inhibition-contact (2) at least in part during extinguishing state.

10. as each described high power switch in the above-mentioned claim, it is characterized in that, described constant in the inner at interval basic maintenance of distance apart from d.

11. be used to disconnect the method for the high power switch that is full of with a kind of arc extinguishing gases, this high power switch has one first arc contact (1) and one second arc contact (2) and has an insulation nozzle (5) that has a narrow positions (6), and this method comprises the following steps:

-two arc contacts (1,2) are separated from each other, light the electric arc (4) between described two arc contacts (1,2) thus, heat arc extinguishing gases by electric arc, it is temporarily stored in a heating chamber (11) the inside;

-by arc extinguishing gases stream (s3) make arc extinguishing gases from heating chamber (11) by narrow positions (6) along an axis (A) and guiding an expansion position (21) that is connected on the narrow positions (6), wherein narrow positions (6) close expand position (21) have one perpendicular to axis (A), area is the cross-sectional area of F;

-during this arc extinguishing gases stream (s3), at least under situation about connecting-arc extinguishing gases stream (s3 therein, s4) at least partly can with the velocity of sound or supersonic speed flow-one parallel to the axis that (A) plug is measured, between narrow positions (6) and second arc contact (2) (s3 s4) at least partly can be with the velocity of sound or the through-flow the same distance inside at interval that remains on for a long time of supersonic speed with making arc extinguishing gases stream at least apart from d;

-wherein said distance depends on the geometry of area F, second contact (2) and the geometry at expansion position (21) at interval, and

-wherein said distance provides at interval thus,

-on the one hand, apart from the interval limit, in expansion position (21), have the area of area F, especially at least 1.5 * F at least for arc extinguishing gases stream (s3) through-flow cross-sectional area corresponding to down,

-on the other hand, corresponding to the last distance limit at interval, in narrow positions (6) or the arc extinguishing gases density (ρ that between narrow positions (6) and second contact (2), is produced ₁) minimum value greater than in second contact (2) the inside or the arc extinguishing gases density (ρ that the next door produced ₂) minimum value.

12. high power switch, it can be full of pressure p one with a kind of arc extinguishing gases ₀Under be full of,

-have one first arc contact (1) and one second arc contact (2),

-have the electric arc (4) that may between described arc contact (1,2), burn,

-have one to be used for the temporary heating chamber (11) that passes through the arc extinguishing gases of electric arc (4) heating, and

-having an insulation nozzle (5), it has the narrow positions (6) that is connected with heating chamber (11) in order to make arc extinguishing gases stream (s3) along axis (A) guiding, is connecting an expansion position (21) thereon,

-wherein this narrow positions (6) near described expansion position (21) have one perpendicular to axis (A), area is the cross-sectional area of F,

It is characterized in that,

-during the later disconnection process of contact separation, arc extinguishing gases stream (s3) can pass on the direction of second arc contact (2) narrow positions (6) extinguish state during, at least under the connection situation, the pressure p of existence in heating chamber (11) wherein _HAt least can be big like this: make ratio p ₀/ p _HBe less than or equal to the Bearing score ear-pressure proportional that is used for blanketing gas,

-one parallel to the axis (A) measured, the distance of the geometry at geometry that being positioned at least so for a long time apart from d between narrow positions (6) and second arc contact (2) depended on area F, second contact (2) and expansion position (21) at interval in, with the pressure p of existence in heating chamber (11) _HAt least equally big, make ratio p ₀/ p _HBe less than or equal to 1/4th of Bearing score ear-pressure proportional of being used for blanketing gas,

-wherein provide distance thus at interval:

-on the one hand, apart from the interval limit, in expansion position (21), have the area of area F, especially at least 1.5 * F at least for arc extinguishing gases stream (s3) through-flow cross-sectional area corresponding to down,

-on the other hand, corresponding to the last distance limit at interval, in narrow positions (6) or the arc extinguishing gases density (ρ that between narrow positions (6) and second contact (2), is produced ₁) minimum value greater than in second contact (2) the inside or the arc extinguishing gases density (ρ that the next door produced ₂) minimum value.

13. high power switch, it can be full of by a kind of arc extinguishing gases,

-have one first arc contact (1) and one second arc contact (2),

-have the electric arc (4) that may between arc contact (1,2), burn,

-have one be used for temporary arc extinguishing gases by electric arc (4) heating heating chamber (11) and

-having an insulation nozzle (5), it has the narrow positions (6) that is connected with a heating chamber (11) in order to make arc extinguishing gases stream (s3) along an axis (A) guiding, is connecting an expansion position (21) thereon,

-wherein this narrow positions (6) near expansion position (21) have one perpendicular to axis (A), area is the cross-sectional area of F,

It is characterized in that,

-during the later disconnection process of contact separation, arc extinguishing gases stream (s3) can pass on the direction of second arc contact (2) narrow positions (6) extinguish state during, at least under the connection situation-arc extinguishing gases stream (s3 wherein, s4) can flow with the velocity of sound or supersonic speed at least partly

-one parallel to the axis (A) measured, between narrow positions (6) and second arc contact (2) apart from d at least with make arc extinguishing gases stream (s3, s4) at least partly can with the velocity of sound or supersonic speed flow the same geometry that is positioned at the geometry that depends on area F, second contact (2) and expansion position (21) for a long time distance at interval in

-wherein provide described distance thus at interval:

-on the one hand, apart from the interval limit, in expansion position (21), have the area of area F, especially at least 1.5 * F at least for arc extinguishing gases stream (s3) through-flow cross-sectional area corresponding to down,

-on the other hand, corresponding to the last distance limit at interval, at narrow positions (6) or the arc quenching gas pressure (p that between narrow positions (6) and second contact (2), produced ₁) minimum value greater than in second contact (2) the inside or the arc quenching gas pressure (p that the next door produced ₂) minimum value.

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