DE19730583B4 - Air blast switch - Google Patents

Abstract

Compressed gas switch with the following features:
- The gas blast switch has at least one point of interruption;
- belongs to the point of interruption in each case a first and a second contact piece (2, 3);
- The contact pieces (2, 3) of the breaker point are coupled via a lever mechanism with a two lever arms (28, 29) Umklenkhebel (27);
- The two lever arms (28, 29) of the reversing lever (27) have different lengths;
- On both lever arms (28, 29) a rod (7, 8) is attached in each case via a rotary joint;
- The first rod (7) is rotatably coupled to the first contact piece (3); and
- The second rod (8) is rotatably coupled to the second contact piece (2).

Description

The The invention relates to a compressed gas switch with two against each other movable contact pieces.

Such a gas blast switch is from the essay
Toda, H. et al.: Development of 550kV 1-Break GCB (Part II) Development of Prototype;
in: IEEE Transactions on Power Delivery, Vol. 8, no. 3, July 1993, pages 1192-1198
known. The displacement of a contact piece is transmitted via a lever mechanism to the other. For this purpose - are symmetrical to the central axis of the gas pressure switch - two lever available, are rotatably mounted on the two rods. About the rods both contacts are symmetrically connected to opposite ends of the lever.

Of the known gas blast switch operates on the conventional autopneumatic Principle. This means that the for the Arc extinction necessary pressure even at large Flow mainly through a compression device is generated in the switching chamber. Accordingly the known compressed gas switch has a compression device on, with the help of those in a turn-off by the movement a compression cylinder against a stationary piston insulating gas compressed and then to delete an arc is used.

The Compression of the insulating gas to the required pressure is only possible, when the compression cylinder and the associated contact piece with a relatively high minimum speed is moved. Consequently, must the switch drive for this speed be dimensioned. The minimum speed increases with decreasing diameter of the compression device. Because of economical reasons one strives to keep the diameter as small as possible.

Also from the EP 0 313 813 is a high voltage switch with two mutually movable contacts known, of which only one is driven directly. At this contact piece a Isolierstoffdüse with a coaxially surrounding this conductive shield is attached. This carries two parallel racks, each interacting with a gear associated with them.

each the two gears on the one hand engages in one of the two racks and on the other in another rack, to which the not connected to the insulating nozzle contact piece is coupled. The gears cause a reversal of the direction of movement, the contact pieces thus always shift in the opposite direction. The gears need to be very high Loads are designed as they abruptly at Ausschaltvorgangen be exposed to high speeds.

Of the High voltage switch works with a blowing device for the arc. This causes decomposition products that cause the arc with his generated high energy, distributed very far inside the switch and thus also get into the rack and pinion gear. This reduces the reliability of the high-voltage switch in the case of a multi-year operation.

Of the Invention is based on the object, a compressed gas switch to create, with the at a switch-off a high contact separation speed is achieved at low drive power.

These The object is achieved by a compressed gas switch according to claim 1.

If both contact pieces using the lever mechanism to move in opposite directions, if the relative speed between them is greater than the speed, with which the drive sets one of the two contact pieces in motion. In this way, with low drive energy, a high contact separation speed reached.

This is especially useful in gas blast switches that operate on the pressure chamber principle. In such switches, the arc provides the energy for his Blowing when turning off big Streams. For this purpose, heated from the arc insulating gas first in a pressure chamber. Near of the current zero crossing triggers this heated insulating then a Isoliergasströmung from the Pressure chamber in the area between the contact pieces. Only for the interruption of small currents is a compression device required, but only small Generate extinguishing pressures must and can be moved with a correspondingly low speed. For an arc blowing is thus only a right in such high voltage switches low drive speed required. A high contact separation speed but is also in such switches for the recirculation-free interruption of capacitive currents necessary.

A reduction of the drive energy can be achieved by the speed is divided differently between the two contact systems. In this case, it is favorable to choose the speed of that contact system which has a lower mass higher. When splitting the Ge The following must be noted with regard to speed: The speed of the other contact system also decreases with speed. Both quantities determine the compression in the compression device that is coupled to the contact system. This results in an additional condition for the optimization of the drive energy.

With the switch type according to the invention a high contact separation speed at a switch-off achieved at low drive power. The energy for the elimination is considerably reduced, but still a fairly high breaking capacity is achieved. For switches according to the pressure chamber principle come Advantages of the lever mechanism according to the invention so very good effect.

There the axis of rotation of each reversing lever in the center axis of the gas pressure switch lies, he lets himself produce the same diameter as conventional gas blast switches. This is particularly advantageous when used as an outdoor switch with a porcelain insulator is sealed gas-tight. The cost of a porcelain insulator rise considerably larger with its diameter. The lever mechanism is a special one simple and robust means to cause an opposite movement of the contacts. Because the power transmission over the insulating takes place, the lever mechanism itself needs no insulating To contain elements (e.g., insulating bars).

One cup-shaped Contact unit body takes care of a dielectric shield of the reversing lever with its hinges against the point of interruption.

through a power transmission element at the insulating nozzle becomes the fulcrum of the first rod attached to the insulating nozzle guided in a straight line.

• 1. Die Schlagweite entlang der Düsenaußenwand kann wesentlich größer werden als die Schlagweite in SF6. Dies ist wichtig, weil die Spannungsfestigkeit an der Isolierstoffoberfläche an der Außenseite der Düse im Vergleich zum SF6 durch Verschmutzung und Fremdpartikel herabgesetzt sein kann. Dies gilt bereits für den Neuzustand, aber noch mehr für den langjährigen Betrieb.
• 2. Auch die Schlagweite entlang der Düseninnenwand wird in ähnlichem Maße vergrößert. Diese Düseninnenwand ist durch die Lichtbogenbeanspruchung im Betrieb starken Beanspruchungen unterworfen.
• 3. Weiter wird auf diese Weise erreicht, daß die dielektrische Beanspruchung des festen Isolierstoffes der Düse stark vermindert ist. Dies ist für einen langjährigen störungsfreien Betrieb wichtig, weil sich Schädigungen im festen Isolierstoff akkumulieren können.

Preferably, the force transmission element, which is located with respect to the power flow between the insulating nozzle and the lever, is arranged at a greater distance from the opposite contact body in the interior of the contact unit body. As a result, the metallic connecting elements of the power transmission element are electrically shielded. These important transmission elements can thus be optimally designed without regard to the electric field strength. Further advantages of this design are:

• 1. The impact distance along the nozzle outer wall can be much larger than the impact distance in SF6. This is important because the dielectric strength on the insulating surface on the outside of the nozzle can be reduced by contamination and foreign particles compared to the SF6. This applies already for the new condition, but even more for the long-term operation.
• 2. The distance along the nozzle inner wall is increased to a similar extent. This nozzle inner wall is subjected to strong stresses during operation due to the arc stress.
• 3. Next is achieved in this way that the dielectric stress of the solid insulating material of the nozzle is greatly reduced. This is important for years of trouble-free operation because damage can accumulate in the solid insulating material.

Polytetrafluoroethylene rings take care of a maintenance-free good sliding of the power transmission element to the Inner wall of the hollow cylinder.

If the power supply has the shape of a tube and the bell crank housed in this tube is this, by simple means and thereby particularly effective dielectrically shielded. The lever mechanism additionally against decomposition products to protect, is very easy.

When tubular power supply Such can be used as in conventional gas-blast switches is used (for example, in a gas blast after the Page 4 in the company brochure "SF6 Circuit Breaker with spring energy drive. 72.5-170 kV ", A22 V.7.104 / 0993 DE of AEG Aktiengesellschaft, D-34123 Kassel-Bettenhausen). The diameter of the equipped with a lever mechanism gas blast switch so stays opposite usual Gas-operated switches unchanged.

By an encapsulation, the sliding bearing in particular against penetration protected by decomposition products, which arise under the action of arc energy. This is Such a lever mechanism with regard to a long-term use reliable as a gear with gears.

One Lever mechanism made of metal is characterized by its stability; this has a particularly advantageous effect on the two (long) rods from which are attached to the Umklenkhebel.

in the The following will be an embodiment of Invention with reference to two drawings, from which further details and advantages, closer described.

It demonstrate

1 a compressed gas switch in the off position in section,

2 the compressed gas switch off 1 in the on position and

It shows the 1 a longitudinal section through a vertical Schalterpol a gas pressure switch in the off position.

The compressed gas switch is filled with insulating gas, for example SF ₆ , and laterally from a tubular insulator 1 surround. With regard to the switch type, it is an outdoor switch.

The compressed gas switch has two counter-rotating along its central axis M contact pieces 2 and 3 on, which form an interruption point. The contact piece 2 is a contact pin and at the bottom of a cup-shaped contact unit body 4 appropriate.

The contact unit body 4 surrounds the contact piece 2 and the center axis M of the gas pressure switch coaxial and points with its opening in the direction of the point of interruption, namely downwards.

The contact unit body 4 projects telescopically in a tubular, open towards the interruption part of a power supply 5 (for the contact piece 2 ) and is movable out of it. The power supply 5 also coaxially surrounds the center axis M of the gas pressure switch. Within this power supply 5 is above the contact unit body 4 a bellcrank 6 arranged, whose axis of rotation 17 the longitudinal axis of the gas pressure switch intersects at a right angle.

The lever 6 has two different length lever arms 28 . 29 on, at the outer ends of each rotatable rod 7 . 8th is appropriate. Both bars 7 . 8th stick down. The pole 7 is rotatably at its lower end in the upper end of a Isolierstoffdüse 9 attached. The insulating nozzle 9 surrounds laterally the mutually facing ends of the contact piece 3 and the contact piece 2 ,

The insulating nozzle 9 is at the upper end of a hollow cylindrical metal contact body 10 attached, which coaxially both the center axis M of the gas pressure switch and partly the contact piece 3 encloses.

In this contact piece 3 it is a tulip contact, the contact piece in the on state of the gas blast switch 2 touched at its end on the circumference.

The contact piece 3 is at the bottom of the contact body 10 attached and electrically connected to him.

Between the contact piece 3 and the insulating nozzle 9 There is a small gap that provides a connection between the area between the contact pieces 2 and 3 (Switching path) on the one hand and the interior of the contact body 10 on the other hand.

The compressed gas switch works according to the pressure chamber principle. The interior of the contact body 10 is closed at the end facing away from the point of interruption by a bottom. The interior of the contact body 10 serves as a pressure chamber 19 , In this pressure chamber 19 penetrates at a switch-off first heated by the arc insulating gas. Near the current zero crossing, the gas pressure in the switching path decreases, and it flows in the pressure chamber 19 buffered insulating gas through a in the insulating material 9 bottleneck in the area of the switching path and blows the arc.

For small breaking currents, the blowing of the arc is generated by means of a compaction device, which consists of the front part of the power supply designed as a fixed cylinder 14 and a movable piston 21 which at the same time is the bottom of the pressure chamber 19 is. The moving piston 21 and the cylinder enclose a compression space 20 ,

The quenching gas flows from the compression space at the blowing of the arc 20 via check valves 23 to the pressure chamber 19 and from there to the insulating nozzle 9 , Überdurckventile 24 limit the pressure in the compression space 20 and thus relieves the drive 11 ,

check valves 25 give the gas flows in the compression chamber at the time of switching on 20 free.

By means of a motor drive 11 , which is arranged in the lower part of the gas pressure switch, is a vertically arranged in the center axis M of the gas pressure switch actuator rod 12 during a power up and during a power down moves. The drive rod 12 sits down in the direction of the point of interruption in a blowback pipe 26 continued. The drive rod 12 is coaxial with a tubular insulator 13 surround. At the top closes to the insulator 13 the end of a power supply 14 for the tulip contact piece.

The power supply 14 coaxially surrounds the center axis M of the gas pressure switch and is tubular, with its lower end is guided dish-shaped horizontally outwards. There are the outside of the gas blast switch electrical Final options available. Inside is in the plate-shaped end of the power supply 14 an opening for the drive rod 12 available.

On the plate-shaped end of this power supply 14 is the insulator 1 appropriate. The transitions from the insulator 1 and from the insulator 13 to the plate-shaped end of the power supply 14 are each gas-tight.

The contact body 10 can be telescoped into the power supply during switching operations 14 in and out of it. About spring contacts 18 at the top of the power supply 14 are mounted, there is a conductive contact between the power supply in each switch position 14 and the contact body 10 with the contact piece 3 ,

At that the drive 11 opposite end of the drive rod 12 is the blowback tube 26 with the contact body 10 and the insulating nozzle 9 attached. The insulating nozzle 9 points to her from the contact piece 3 opposite end of a plate-shaped power transmission element 15 made of metal, extending from the insulating nozzle 9 radially to the inner wall of the cup-shaped contact unit body 4 extends. In this case, there is the inner wall of the contact unit body 4 a sliding connection with one or more PTFE rings. In this way, the insulating material becomes 9 with the rod rotatably mounted thereon 7 guided.

Simultaneously with the rod 7 the other moves on the lever 6 mounted rod 8th , It is with its lower end via a hinge at the bottom of the contact unit body 4 attached, at the side facing away from the point of interruption.

The contact unit body 4 is through the tubular part of the power supply 5 guided. This is also for a linear guidance of the power transmission element 15 taken care of, which in turn within the contact unit body 4 is slidably mounted. spring contacts 22 on the inner wall of the power supply 5 provide a conductive contact between the power supply 5 and the outer wall of the (metal) contact unit body 4 ,

The power supply 5 goes over into a lid that holds the insulator 1 closes gas-tight at the top and on the outside electrical connection options are available.

During a switch-on process, the drive rod becomes 12 with the blowback tube 26 and the contact body 10 moved upward, while the contact unit body shifts 4 downward.

When reaching a certain stroke, first come the contact pieces 2 and 3 in contact with each other. In the course of the further switch-on movement, the rated current contacts come 16 at the bottom of the contact unit body 4 are fastened, with the outer wall of the contact body 10 in contact and allow a flow of current through the upper power supply 5 , the contact body 10 and the lower power supply 14 , Even in the closed position, the (nominal) current flows through the mentioned elements.

2 shows the gas pressure switch in the closed position. The individual parts are provided with the same reference numerals as in 1 , In comparison with this Fig. It can be clearly seen that the lever 6 now inclined to the other direction.

In a turn-off, first the electrical connection between the contact body dissolves 10 and the rated current contacts 16 , The current then commutates to the contact pieces 2 and 3 ,

In the course of the switch-off also these contacts separate 2 and 3 and an arc is formed between them.

The relative speed between the contact body 10 and the contact unit body 4 is the sum of the absolute velocity of the contact body 10 and the absolute speed amount of the contact unit body 4 ,

For the recirculation-free interruption of capacitive currents, the relative speed of the "contact systems" (contact body 10 / Contact piece 3 and contact unit body 4 / Contact piece 2 ) crucial to each other. On the other hand, the absolute speed of the compression device is of minor importance in switches operating on the pressure chamber principle. With the described gas pressure switch, it is thus possible - with the same breaking power - the absolute speed of the contact body 10 to reduce considerably. The drive therefore requires significantly less energy.

The lengths of the two lever arms 28 . 29 behave like 2 to 3. The rod 8th that with the contacts 2 . 16 is coupled with the longer arm 29 , and the pole 7 is with the short arm 28 connected. This will ensure that the speed of the contacts 2 . 16 is larger.

The moving masses of the two moving "contact systems" - contact body 10 / Contact piece 3 and contact unit body 4 / Contact piece 2 - are usually different. Dimensioning the two lever arms 28 . 29 so that the "contact system" with the lower moving mass, this is in usually the "contact system" consisting of contact unit body 4 / Contact piece 2 , is moved faster than the "contact system" with the larger moving mass, so the energy demand can be further reduced.

1

insulator

2

(Second) contact piece

3

(First) contact piece

4

Contact unit body

5

power supply

6

Umlenkhebel

7

(first) pole

8th

(second) pole

9

insulating

10

Contact body

11

drive

12

drive rod

13

insulator

14

power supply

15

Power transmission element

16

Rated current contacts

17

axis of rotation

18

spring contact

19

pressure chamber

20

compression chamber

21

(Movable) piston

22

spring contact

23

check valve

24

Pressure relief valve

25

check valve

26

blow back tube

28

short poor

29

longer poor

Claims (5)

Compressed gas switch with the following features: - the gas blast switch has at least one point of interruption; - to the point of interruption belongs in each case a first and a second contact piece ( 2 . 3 ); - the contact pieces ( 2 . 3 ) of the breaker point are via a lever mechanism with a two lever arms ( 28 . 29 ) Umklenkhebel ( 27 coupled; - the two lever arms ( 28 . 29 ) of the reversing lever ( 27 ) have different lengths; - on both lever arms ( 28 . 29 ) is in each case via a rotary joint a rod ( 7 . 8th ) attached; - the first pole ( 7 ) is rotatable with the first contact piece ( 3 coupled; and - the second rod ( 8th ) is rotatable with the second contact piece ( 2 ) coupled. Gas-blast breaker according to claim 1, characterized in that the ratio of the lengths of the two lever arms ( 28 . 29 ) Is 2 to 3. Gas-blast breaker according to claim 1 or 2, characterized in that the longer arm ( 29 ) with the second contact piece ( 2 ) is coupled. Gas-blast breaker according to one of claims 1 to 3, characterized in that the contact pieces ( 2 . 3 ) of the point of interruption by means of a single drive ( 11 ) are displaceable against each other along the central axis (M) of the gas pressure switch in opposite directions. Gas-blast breaker according to one of claims 1 to 4, characterized in that the axis of rotation of the reversing lever ( 27 ) crosses the central axis (M) of the gas blast switch at right angles.