DE627208C - Device for interrupting an alternating current circuit with the help of a tight insulating sleeve - Google Patents

Description

Device for interrupting an alternating current circuit with the aid of a tight insulating sleeve It is known to facilitate the interruption of high power circuits to switch on a series resistor in front of the switch.

Up until now it was only possible to use relatively small resistances To switch on ohmic value, since with a larger ohmic value the done in the resistor Power becomes so great that the series resistance precludes its practical use large dimensions.

The invention consists in a device which enables the connection of a series resistor with a very high ohmic value and at the same time small dimensions. It is based on the device known from patent 626 72o, consisting of a narrow insulating envelope for the arc, to which a semiconducting liquid is supplied under external pressure in such a way that it can follow the shrinking arc cross-section without delay in the current zero passage.

The invention consists in that to that within the insulating hut created part of the interruption path additional arcs in series to be pulled.

It is thereby achieved that the forming in the insulating sleeve Liquid resistance of high ohms only for a very short period of time, namely is switched on for the low-current pause of the AC arc, which is why the amount of energy absorbed by the resistor does not reach an impermissibly high value and can be removed with practically applicable means. The formation of the fluid resistance in the envelope is with an interaction between the arc and the liquid -explain in the case. The liquid in the shell works namely on the drawn arc extinguishing, so that the insulation resistance of the arc path during the low-current pause of the alternating current arc increases so much, that the power line passes from the arc to the liquid and the arc thus in turn causes the activation of the liquid column.

To switch on the highest possible liquid resistance To bring about, it is necessary to determine the resistance of the parallel connected to the liquid Arc path in the low-power, break up as quickly as possible to drive. This can. Expediently be done in that the liquid with the Arc on a certain_ length., brought intimate contact and the fluid in the vicinity of the light arc is thereby continuously renewed becomes, - that gas and liquid in violent flow in the direction of the interrupted section be moved. This means that the gases in the immediate vicinity are a good conductor the arc column continuous through liquid with that of the liquid's own high resistance replaced. In particular, the liquid follows in each case when the current passes through zero after the shrinking cross-sectional arc without delay. The energy will. - Discharged quickly in. The expanding steam.

In a switch according to the invention, it is possible in particular to have high-power current circuits of very high levels. Tension - to interrupt, namely - with. non-insulating liquids. The high voltage stress can namely be borne better by the arrangement according to the invention than by the device. according to the main patent alone, since essential parts of the reversing voltage are allotted to the upstream interruption lines, for the following reason: When using water-like fluids as hydraulic fluid for the. When the liquid column is switched on, the extinguishing channel extends the natural low-current break in the alternating current arc. one, namely at the time - which the water channel for heating and evaporation due to the - recurring voltage. second hand. This extension of the low-current pause enables the series arcs connected upstream to largely die down, which increases their resistance and the part of the voltage that is allotted to them. A penetration of the so. The large interruption sections that have been created and are not filled by the liquid are then no longer possible. The length of the currentless or low-current break can be made all the longer; the greater -man = the resistance of the body of liquid in the extinguishing channel, i.e., for example, the greater the length of the liquid channel -night. If necessary, it can be extended from a fraction of the half-wave duration of the alternating current to the full Ilafwave duration and even beyond. In general, it will suffice if it extends over a fraction of a half-wave.

The interruption of the circuit can already be done according to the invention simple lengthening of the arc beyond the extinguishing channel can be achieved, because with a certain length of the arcs the normal cooling conditions suffice to cause the series arc to be so strong during the extended currentless break to let fade away that the interruption line has a sufficient insulation strength regained. So you can get the Löschkailal in the interruption section of a Arrange switch and train it so that when the switch is open to the extinguishing channel subsequent arc pieces are present, which through the -aus the extinguishing channel escaping gases are blown. - E.g. you can connect the extinguishing channel to an or " Expand both ends like a nozzle to increase this blowing effect.

An extinguishing channel equipped with auxiliary contacts can also be used as an auxiliary switch with a main switch, e.g. B. an already existing oil switch, Connect in series, with the auxiliary switch at about the same time as the main switch is turned off. The extinguishing of the arc is then carried out at the main switch very small requirements, so that these are relatively very small can. A compressed air switch or an expansion switch can also be used as the main switch be used. Another advantage of this arrangement is that the activation of the circuit can be done with the main switch, for which you then have a switch selects which is well suited for switching on larger voltages, e.g. B. an oil switch. The triggering of the auxiliary switch must inevitably depend on the main switch take place, e.g. B. with a known automatic release. It becomes practical. always - a little earlier or a little later than the triggering of the main switch. If you set it up like that; that the switching off of the auxiliary switch always a little later takes place, the can from the main switch. developed pressure - used to make the To trigger the auxiliary switch and to control its hydraulic fluid or to press the liquid into the extinguishing channel of the auxiliary switch.

This facility can also advantageously be used in order to in existing systems that are equipped with switches that are too low in power, to increase the switching capacity of these switches significantly.

An advantageous embodiment of the invention is that on one side of the extinguishing channel or drying chambers on both sides be made by one or more walls with central holes for passage of the arc are shielded from the extinguishing channel. You can this way a switch for circuits of very high voltage with a single interruption path obtained, with one contact piece or both contact pieces of the switch one after the other pulled through the extinguishing channel and the adjoining drying room will. The upstream drying room has the effect that it is the formation allows a good isolating interruption section, especially when using semiconducting liquids. The holes in the shielding walls of the drying room with movable shielding devices provided, e.g. B. can be used as rotatable or sliding flaps with a certain distance from the wall that is not too small in order to increase the Voltage gradients of the arc at these sticks and burning of the insulating material to prevent being trained. You can also use the upstream drying rooms so train that they have additional extinguishing effects on the arc drawn therein exercise, for example by moving the walls surrounding the arc path from gas-emitting substances, e.g. B. Borax, fiber, or by the fact that one for the creation of a strong gas flow through the arc cares.

Exemplary embodiments of the invention are shown in the drawing.

In Fig. Io i is the quenching device, ii the fixed contact piece 12 and the switching pin of the - switch. 13 is the refill container for the extinguishing device and 14 is a pressurized gas cylinder. The extinguishing device io consists of an insulating body; which has a central bore 15, the extinguishing channel. This channel is widened to a cavity 16 in which the walls 17, 18 made of insulating material are built. These walls are widened too conically towards the extinguishing channel, so that only narrow annular slots 19 to 21 remain free between the walls for the supply of liquid into the extinguishing channel 15. The cavity 16 also has a widening 22 at the top, which serves as an air chamber in order to buffer the rapid pressure surges caused by the alternating current arc. The extinguishing channel 15 is continued upwards and downwards in the insulating body in the form of widening nozzles 23, 24. The liquid container 13 is connected to the cavity 16 via an inflow channel 25. In this inflow channel, a shut-off device 26 is installed, which is controlled as a function of the switching process. This control is not shown in the drawing. You can z. B. be an electromagnetic control of the valve 26 depending on the trigger of the switch. The container 13 is connected to the compressed gas cylinder 14 by a pressure gas line 27 via a pressure reducing valve 28, so that there is a constant gas pressure of, for example, 20 atm in the space 29 above the liquid level in the vessel 13.

The switch is shown in the drawing at the moment shortly before the power interruption. Since the contact piece ii is fixed at a certain distance from the quenching channel and the switching pin i2 was also pulled a certain distance beyond the quenching channel when the power was interrupted, the arc to be quenched consists of three parts, namely the part 30 above the quenching channel 15, the part 31 within the extinguishing channel and the part 32 below the extinguishing channel. 30 and 32 burn partly in the nozzles 23, 24. - In the substitute diagram of FIG. 2, the resistances of these parts of the interruption path are shown. The arc piece 3o has the resistor R1, the arc piece 31 the resistance. stood r and the arc piece 32 the resistor R2. The resistance w of the liquid in the extinguishing channel lies parallel to the arc 31 in the extinguishing channel 15. All of the resistors are connected to the operating voltage E. When the interruption process was initiated, the valve 26 was opened and the space 16 was thereby filled with hydraulic fluid from the container 13. From the space 16 the liquid penetrates through the slots 19 to 21 into the extinguishing channel. As soon as the arc is drawn through, a thin vapor jacket is formed around the arc column, which quickly flows out in the axial direction. As the alternating current approaches zero, as a result of this rapid axial expansion of the vapor envelope of the arc on the one hand and the clamping effect of the pressure fluid on the other hand in the immediate vicinity of the arc, the hot gas is replaced by liquid at any moment, which results in a rapid constriction of the arc takes place on an increasingly narrowing fluid channel. Due to the high heat absorption / cm3, which the liquid has up to its evaporation, the gaseous channel in the liquid is increasingly withdrawn from its conductivity, as a result of which the current line passes over to the liquid column.

The resistances R1 and R2 of the arcs connected to the extinguishing channel and the resistance r of the arc in the channel are very small during the current maximum. In the vicinity of the current zero crossing, these resistances now rise very rapidly. The resistance r rises particularly rapidly as a result of the cooling conditions in the extinguishing channel. When the current passes through zero, the resistance r - becomes so great that the parallel connected resistance w of the liquid takes over the current. The voltage; which takes up the interruption path after the current has passed through zero, is now distributed among the three series resistors R1, R2 and w. The voltage component that is attributable to w must now be kept as small by keeping the resistors R1 and R2 high . be, 'that a breakthrough of the extinguishing channel no longer takes place. If water or a liquid similar to water is used, for this increase in the resistances R, and R2, the gain in time can be made use of, which takes place in the extension of the currentless pause by switching on the liquid instead of the arc line in the channel namely with water-like rivers. the breakdown by the electrical voltage is a heat breakdown; A longer time is required to heat up the liquid than to heat up a gas section of the same length until the breakdown: - As long as the liquid has not yet broken down, the current is of course very low due to the specific resistance of the liquid. At this low current, however, the resistances Ri and R2 of the series arcs 30 and 3a are also very high. This delay time, -during which only, the current confined by 'the fluid resistance current flows ;, is to - use cancellation of the series arcs.

In the present example the series arcs 30 and 32 are blown by the gases expanding out of the extinguishing channel and the effect of this blowing is further supported by the fact that the expanding gases are guided into nozzles 23, z4. The arcs 30, 32 'therefore increase their resistances very quickly and thereby limit the load on the extinguishing channel below the amount required for its breakdown. 3 shows another embodiment of the invention. This embodiment is particularly suitable for switches for very 1% he voltages. 40 is an insulating body with the extinguishing channel 41, to which the pressure fluid, z. B. pressurized water, in 'the direction of arrow 43 is supplied during the interruption. The fixed contact 44 is fastened below the channel 41 at a certain distance. Above the extinguishing channel there is a space which is shielded from the channel 41 by the insulating wall 45 and which is delimited by the side walls 46, 47 and the upper wall 48. The transverse walls 49, 50 are built into it. The walls 45, 48, 49, 5o have narrow central holes for the switching pin 51. In the side walls 46, 47 wide holes 52, 53 are made. The arcing spaces between the plates 45, 49 and 50, 48 are narrowed by transverse walls 54 to 57. 58 is a flap; which can be rotated about a pin 59 ' - and is rotated into that position by a spring when the Bern switch pin is pulled out. in which it stands in front of the switch pin opening 6o. The switching pin 51: however, turns the flap 58 downwards when it is down, so that it - releases the switching path. The flap 58 is attached at a certain distance 61 from the wall 45. 62 is a vessel which serves to collect the liquid emerging from the extinguishing channel 41. The switch works as follows: When the timing is interrupted, the supply of pressure fluid is initiated through channel 42. The pin 5i then goes through the extinguishing channel 41 and pulls the arc through the extinguishing channel, where it burns in intimate contact with the liquid. During the further upward movement of the .Stift -5 r occurs over the flap 58, which until then was held by the pin in the dashed position, and this now rotates upwards to the horizontal. Location; in which it shields the opening 6o. The pin then goes through the opening 6o of the wall 45 and pulls the arc into the dry space, which is shielded from the liquid ejected from the channel 41 by the door 58 and the wall 45. The arc bends to the left and goes through the space 61 between flap 5-8 and wall 45. - That part of the arc that is drawn into the drying room is now exposed to a gas flow that forms through the switch pin openings of the plates 45, 49, 5o and 48. In the position shown, the switching pin 5s takes z. B. the pressure within the area of the plates q.5; 49, 54 and 55 limited space to a higher value, as the pressure in the space above the plate 49, whereby a lively, pressure-equalizing flow of heated gases through the opening 63 enters hinddrch. Under the effect of this blowing and lengthening, the resistance of the arc part above the flap 58 increases rapidly. When the current passes through zero, the arc is extinguished in the extinguishing channel 4z and instead the liquid in the channel 41 is now in front of the arc. The voltage and thus the current load or liquid column in the channel 4.z is so severely limited after the current zero passage by the high resistance of the upstream arc that reignition in the extinguishing channel 41 no longer occurs, but the arc extended into the drying room also goes out. Since the part of the interruption section located in the drying room is protected against the semiconducting liquid escaping from the extinguishing channel, it has good insulation properties and as a result secondary reignitions via wetted walls no longer occur.

To extinguish the arc, which through the walls 45, 49, 50, 48 is pulled through, also contributes the wall effect created by the narrow switch pin openings goes out. You can increase this effect by making the walls out of one gas-emitting pulp, e.g. B. made of fiber, wood or pressed borax.

4 shows the series circuit as a further embodiment of the invention a main switch 70, e.g. B. an ordinary oil switch, with an extinguishing channel 7i. The line leads from the oil switch via the fixed contact piece 72 and through the switching pin 73 passing through the channel 71, from which the current is, for example, with Using a sliding contact 74 is removed. 75 is the channel for the liquid supply to the extinguishing channel 7i, 76 a shut-off valve. 77 is a liquid container and -78 a pressurized gas cylinder that is about. a pressure reducing valve 79 and the pressurized gas line = device 8o is in communication with the container 77 and, as in the case of FIG the container maintains a certain pressure, which is read on the pressure gauge 9o can be. In the line 81 there is an overcurrent release 82 on its contacts Trip circuits with trip coils 84 and 85 are connected. The trigger coil 84 opens the valve 76, while 85 causes the switching pin 73 to be triggered.

The mode of operation of this arrangement is as follows: Slight shutdowns the oil switch 70 alone coped with, however, as soon as a short-circuit-type current is switched off that would overload the oil switch alone, the overcurrent release speaks 82 at. As a result, the coil 84 is energized and opens the valve 76, whereby Liquid from the container 77 through the supply channel 75 into the extinguishing channel 71 is pushed in. The coil 85 is also traversed by the current and releases the Switch pin 73 off. This is pulled out of the contact 72, whereby a with the interruption path of the oil switch in series lying arc through the Extinguishing channel 71 is pulled through. It switches itself on at the first current zero crossing now in the same way as discussed in the embodiment Fig. i, the liquid in the quenching channel as a resistance in front of the interrupting arc in the oil switch, and this resistance is sufficient to instantly start the arc in the oil switch Bring extinction. In this way it is achieved that the circuit in the oil switch is interrupted after a few half waves, before the arc in the oil switch such Has assumed lengths that the oil switch is overloaded.

You can also use another switch instead of the oil switch, z. B. a compressed air switch or an expansion switch.

Instead of triggering the auxiliary switch depending on the overcurrent 'You can also do it from the pressure in the oil switch or from the switch-off path of the oil switch traverse make them dependent.

For example one can'die tripping circuits of the auxiliary switch Connect to a pressure gauge on the oil boiler. It is also possible to use the main switch pressure caused by the main arc directly to push in the Use liquid in the extinguishing channel.

Since the auxiliary switch is only used in the event of severe short circuits, i.e. rarely comes into function, can. he. be trained very easily, e.g. B. he doesn't need one to have remotely controllable switch-on mechanism. As the consumption of hydraulic fluid is small, the bottle 78 can also be omitted, instead the space above the liquid Form larger in the container 77 and only after each short-circuit release of the auxiliary switch Refill with pressurized gas. .

Claims (6)

PATENT CLAIMS: i. Device for interrupting an alternating current circuit with the help of a narrow insulating sleeve according to patent 626 72o, which is a semiconducting Liquid is supplied under external pressure in such a way that it is in the current zero passage can follow the shrinking arc cross-section without delay, characterized in that to the part created within the insulating sleeve the interruption path additional arcs in series are drawn. 2. Device according to claim i, characterized in that the insulating sleeve in the interruption path of the switch according to the main patent like that is arranged and designed so that when the switch is open to the extinguishing channel subsequent arcing pieces are present, which by the from the. Insulating sleeve the escaping gases are blown. 3. Device according to claim i, # characterized that an extinguishing channel equipped with auxiliary contacts with a main switch in series where the auxiliary switch = approximately 'at the same time as the. Main switch switched off will. 4. Device according to claim r, characterized in that on one side of the extinguishing channel or drying rooms on both sides are arranged, which are through a or several walls with central holes for the passage of the light 'arch against the extinguishing channel are shielded (Fig: 3): 5. High-voltage switch after spoke q., characterized in that the holes in the shielding walls can be moved with shielding - facilities are provided. 6. High-voltage switch after spoke 5, characterized in that rotatable or slidable plates on the walls (58) are arranged at a certain distance from the wall. i- high voltage switch according to spoke 4a_ characterized in that the extinguishing channel = switched on Dry rooms are designed and arranged so that they - an additional extinguishing effect on the arc drawn in it by the extinguishing agent emerging from the extinguishing channel enable. B. Device according to claim i, characterized in that the extinguishing channel is expanded nozzle-shaped at one or both ends. , 9. Device according to claim 3, characterized, .that the auxiliary switch is so dependent on the to be interrupted overcurrent is controlled that its contacts and its liquid supply can only be triggered in the event of very strong overcurrents. i o # device according to claim i, characterized in that the developed from a separate main arc Direct pressure to press the liquid into the extinguishing channel or for control of the auxiliary switch and the hydraulic fluid is used for the auxiliary switch.