DE1640286A1 - High voltage switch - Google Patents

Description

4498-68 / H / Ro. _Λ ~> _ηΟβ Λ

Docket No. llD-2859 IO ⁴ + U £ 00

(Christy WiIkes Bell) ■

US Ser.No. 6l8,405

US Filing Date: February 24, I967

General Electric Company, Scheneetady, HJ., V.St.A.

He switches high voltage

The invention relates to a Hochspännungsschalter with a plurality of electrically i _n series-connected sets of separable contact parts, the switch is open all separately and are movable during closing of the switch in a Berührungsiage, and associated with each contact set, the voltage controlling resistor specific to a Time during the closing of the switch can be switched in parallel * to the associated contact set.

In particular concerns; the invention of a high-voltage switch, at which the circuit through the switch during a closing process to a precisely controlled tent point closed will.

To the size of the closing of a high voltage switch To limit the voltage surge that occurs, it was proposed that to provide the switch with resistors that are in the power

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circuit can be switched on immediately before the main contact pieces touch and close the circuit. These Resistances are generally parallel to the. Main contact pieces and in series with appropriately controlled resistance holders, which are closed and the resistors at an appropriate time before touching the main contact switch on pieces. . .

If present in a high voltage circuit lying resistance switch more in, series _a 1st it important that all resistance switches are closed substantially simultaneously. Otherwise the gap between the contacts of the last resistor switch to be closed can be so large that it is not immediately broken down by the high voltage applied to these contacts when the other resistor holders are closed. This high voltage can lead to a destructive arc across the voltage exposed insulation.

The invention therefore aims, to provide a switching device in which the resistors to a precisely controlled; Time can be pre-switched, so a practically simultaneous pre-insertion of all resistors connected in series is possible. ''^ ^r

The magnitude of the voltage surge caused by the closing of the switch can still be controlled by that one controlled the point on the voltage wave at which the resistors are switched on. In the Skeat's essay

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. In the journal ¹¹ AIEE transactions, Volume-6ö, Part II, 1949 ", pages IO58-IO67, it is stated, for example, that a voltage surge with minimal amplitude occurs when the closure takes place at or near voltage zero. Another purpose of the The invention accordingly consists in specifying a device by which the pre-insertion of the resistors is possible at a certain point on the voltage wave.

In a preferred embodiment of the invention A high voltage switch contains a plurality of sets of separable contact pieces which are electrically connected in series are. The series connection is parallel to each contact set from a voltage-controlling resistor and a triggerable one Switching path. Each switching path contains separate main electrodes, which form a gap or a flashover path, in series with their associated resistor and one Carrying device for causing a rollover through this gap when a trigger signal is sent to the trigger device is created. It is a "-during a closing process of the Switch operable device provided which is connected to the The triggering device of these rollover sections supplies trigger signals that are practically simultaneously in all of these sections Initiate flashovers before the contact sets touch.

To explain the invention are in the following on hand the drawing besehrieben preferred embodiments. the Drawing shows in:

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Pig. 1 is a schematic representation of a switch according to a particular embodiment of the invention;

Fig. La.a schematic representation of a modified embodiment the invention;

2 shows a schematic representation of another modified embodiment of the invention;

Fig. J5 shows a further embodiment of the invention and

4 shows another modified embodiment of the invention.

In Fig. 1 is a schematic high-voltage electrical switch shown, the two main contact pairs 11 electrical connected in series in a high voltage AC circuit I ^ are. Each main contact pair contains a stationary contact piece 12 and a movable contact piece 14, which in vertical Direction can be brought into contact with the stationary contact piece or separated from it. By means of a conductive contact bridge 15 on which an insulating actuating rod 16 "is attached", the movable contact pieces are electrically and mechanically connected to one another.

In Fig. 1, the switch is in its full lines open position "shown, with its main contact pieces 14 of their corresponding stationary contact pieces 12 are separated. When the operating rod l6 by a suitable drive device (not shown) is moved upwards, the

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movable contact pieces l4 together with the contact bridge 15 lifted until the contact pieces 14 come into contact with the stationary Contact piece 12 come and thereby close the switch, with each broken line 1? is the location of the moving contact pieces shown when the switch is closed. The contact bridge 15 mechanically couples the moving contact pieces together, so that it is ensured that both contact pieces © 14 each other during a closing process / together and in agreement move and their corresponding stationary contact piece 12.approx touch at the same time.

The switch is opened by pushing the movable contact pieces 14 from their position shown with broken lines IZ down "into their position shown with solid lines. The opening force is transmitted via the actuating rod 16 and the mechanical coupling through the contact bridge 15 causes the movable contact pieces l4 to be separated from their associated stationary contact pieces practically at the same time.

To limit the size of the switch when closing evoked. Voltage surge is the switch with low resistance Resistors 50 oversight that occurred during a closing process immediately before touching the main contacts in the 'Performance group can be inserted. Such a connection of the resistors can be called "pre-connection" or "pre-insertion" "\ are designated. When the resistors'30 in the power circuit

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have been switched on, each of them lies parallel to a set or pair 11 of the main contacts 12, 14.

To insert the resistors j? 0 in the power circuit for desired point in time is in series with each resistor and. ~ ".. A triggerable vacuum switching path, generally designated ^ 2, is connected in parallel to the associated main contact set. There these vacuum switching sections can be the same as one another ^ only one of them is shown in detail, while the others can be seen in their outlines. The vacuum switching section 52 has a sealed piston 40 * except for one

Pressure of 10 mm of mercury or lower is evacuated. The piston 40 includes a tubular housing 42 of suitable Insulating material and two metallic end caps 43, 44, the by means of a suitable sealing process, vacuum-tight in each case with the opposite ends of the insulating housing 42 connected are.

There are two inside the evacuated piston 40 Primary or main electrodes 46, 48 separated from each other and between them form a main or primary path / * The upper electrode 46 is in the middle of a conductive support 46a mounted on the upper end cap 4 ^, while the lower Electrode 48 on the lower end cap 44 by means of a tubular conductive support member 48a is supported.

The primary section 50 between the electrodes 46, 48 has a sufficiently high dielectric breakdown strength,

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around the parallel circuit via the resistor JO normally to keep open. It should be noted that the in Fig. 1 Sehalteinrichtung shown is designed for a sufficiently low voltage, so that a single .Schalteinrichtung is sufficient, to withstand the tension built up on the bridged main contact pieces 12 without flashover. For circuits higher voltage, a corresponding plurality of these switching paths are connected in series in the bypass circuit.

So that the main switching path can be ignited if a release or trigger pulse to the triggerable vacuum switchgear is applied is in a central recess 55 in the lower electrode 48 a trigger or ignition path 54 is arranged. This ignition path comprises one located in the recess 55 annular ceramic disc 57 and two thin layers 5ö, OC made of metal adhering to the top of the ceramic plate 57 and are radially spaced from one another. These two pieces of metal form the electrodes of the ignition path. They are marked by a circular notch 62 with a V-shaped cross-section separated, which extends parallel to the circumference of the ceramic disc and its walls through the ceramic material itself are formed. The one formed by the layer 60 Trigger electrode is electrically connected to main electrode 48. The other trigger electrode formed by layer 53 is normally electrically isolated from the main electrode 48. These layers 58 »60 preferably consist of one

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Metal like titanium that contains a large amount of hydrogen is enriched.

It is generally / known that the field lines at the interface between a metal and a ceramic body, which are touch intimately, run in such a way that they very much favor a rollover at this interface. Consequently, one can over The relatively low voltage appearing in the ignition gap causes a discharge from one of the interfaces across the ignition gap initiate. This discharge continues immediately from the trigger electric "." releases the hydrogen, ionizes it and forces electron-ion plasma into the main or primary line 50, over which a lient arc is ignited.

To apply a voltage to the ignition path, a conductor 65 is used, which extends aureh a central passage in the ceramic disk 57. At its upper end, this conductor 65 is electrically connected to the layer 50 forming a trigger electrode. At its lower end, the conductor 65 protrudes through a ceramic plate 6j , which is connected to it and to the lower end cap 44 with a hermitic seal, whereby the lower end of the piston is tightly closed.

The main electrode 46 is shaped to have a The nozzle surrounding the upper end of the conductor 65 forms. This nozzle has one between the ignition path 54 and the primary path 50 located narrowed neck through which ionized plasma exits from the ignition section into the main section to .'- the- main-

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"to ignite the arc. The constriction of this nozzle prevents the Main arc from making a way to the parts of the ignition range search so that these parts are protected from the arc. ·

So at a certain point in time to the ignition gap 54 a trigger pulse can be applied is parallel to the. Ignition gap 54 between the conductor 65 and the end cap 44 a Trigger pulse source 70 switched, which can be of conventional type and is therefore not shown in detail. At a The preferred embodiment of the invention is this trigger pulse source 70 a normally off source that is switched on by means of a light signal which is brought in via a fiber optic light guide 73. To switch on the source 70 on the basis of the reception of the light signal a silicon-controlled direct current, which can be activated by light, richter, a so-called SCR element, in the known way be used.

A suitable lamp 75 is used to generate a light signal for switching on the trigger pulse source 70. This lamp 75 / ^{which is in} a supply circuit 76 is normally switched off. If, however, the feed circuit 76 is closed, a voltage pulse is applied to the lamp, which generates a light pulse with a steeply increasing light intensity. The light pulse runs through the light guide 73 and switches the. a pulse source 70 which can be activated by the light.

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Each trigger pulse source 70 is provided with a light guide 7 $ through which the light pulse from the lamp 75 is transmitted. Since both pulse sources 70 receive their switch-on signal from a common light source, namely the lamp 75. » received, the light pulses obviously reach both pulse sources at the same time. As a result of the reception of the light pulse, both pulse sources 70 are switched on extremely quickly. The pulse sources 70 therefore emit their voltage pulses to their corresponding ignition paths largely simultaneously.

Due to the application of the trigger pulses to the ignition sections 5 ^ · these will break through instantly, and will take place immediately a rollover over their associated primary routes 50. The ge, total time between the generation of the light pulse and the flashover the primary stretch 50 is in the vicinity of 15-20 Microseconds. This time can be controlled by a triggerable vacuum switchgear to the other vary by a few microseconds, so that one route a few microseconds after the other ignites, but this time difference is so small that it is practically meaningless. .

In a preferred embodiment of the invention the light pulse generated at such a time that the

'' triggerable vacuum switching section J52 in the vicinity of a voltage zero point between the power circuit 1> The voltage prevailing on the source side of the switch and ground ignites. this

“Is realized by the fact that the lamp 75 immediately before

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or shortly after such a voltage zero point a voltage; pulse is applied. This timing of the voltage pulse can be accomplished by conventional means. Since the details of the pulse generation and timing circuit 80 are not part of the invention, this circuit is shown only as a block in the drawing. A voltage converter 82 connected between the alternating current circuit Ip and ground on the source side of the switch supplies input information about the mains voltage via an input circuit 85 to the pulse generation and time control circuit SO.

So that the circuit SO does not deliver an output pulse to the lamp 75 before a certain point in time of the normal operation, a normally open control switch 85 is provided, which is coupled in a suitable manner to the movable contact piece 14 of the switch. When the contact pieces 14 of the switch run through a desired point of the closing stroke, the control switch 65 is closed. Thereafter, the next pulse generated by the circuit oO is applied to the lamp 75, whereupon the trigger pulse source 70 is switched on and causes a flashover over the vacuum maintenance section 52. When the switch reaches its position in which it is completely closed, a so-called ¹¹ V or normally closed switch 36 is opened, which prevents further voltage pulses from being applied to the lamp 75 as long as the switch remains closed. This switch So is shown schematically so that it is by means of a

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suitable cam 88 on the operating rod 16 of the switch is controlled.

It is known that the size of the Switch generated voltage surge can be significantly reduced can when the closure is close to the voltage zero crossing is synchronized, but such a synchronized closing has not been attempted in general, since mechanically'ge

t, switches seldom controlled with precision closed that for a matching closure at the voltage zero point is required. With a mechanically controlled switch, minor changes in the start-up characteristics, the speed and the gap width before the rollover cause unpredictable fluctuations in the closing point, which prevents reliable closing at the desired voltage zero point. The one with triggerable vacuum switching sections working switches, on the other hand, can be controlled much more precisely are used as a mechanically controlled switch. As already

"was mentioned, the fluctuations in the total time lie between the Application of the light signal and the ignition of the vacuum switching sections only on the order of microseconds, and this is so rjeringTügig that all triggered vacuum switching sections can be reliably ignited in a small range around the desired point in time at zero voltage. This The point in time can be placed close to "" enough to the voltage zero point, to a large reduction in the size of the

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Sehalten to bring about the voltage surge.

Since all vacuum switching sections ignite practically at the same time, there is a very low probability that the insulation lying parallel to the last switching line to be ignited will be a destructive tension builds up. Before the tension at this last switching line. reach a dangerous height can ignite this path, which prevents a further increase in voltage.

Although the invention works particularly well for a synchronous closing with a special point on the tension wave Switch is suitable, it is understood that the invention also applies to Switch is applicable to which one is not one Trying to close at a certain point in time related to the wave of tension. With such a The voltage converter 82 can be omitted and the switch Voltage pulse can be applied to the lamp 75 when the control switch 85 regardless of the voltage of the power circuit is closed. Such a control causes a-practical simultaneous ignition of the triggerable vacuum maintenance sections J52 and thus protects the insulation parallel to the last one to be ignited Switching tree, as explained in the previous paragraph.

Once the vacuum interrupter has been ignited, it remains conductive until the current flows through the main or primary line practically goes to zero. At this point it becomes normal "extinguish", i.e. it will lose its dielectric

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Regain impact resistance so that further conduction is prevented. So that the vacuum switching paths 32 are not deleted before the point in time at which the main contact pieces 12, 14 touch, repeating voltage pulses are applied to the ignition path 54 when the primary path 50 'begins to conduct. These repetitive pulses prevent the primary path 50 from being extinguished after it has been ignited and before the contact pieces 12, 14 come into contact.

To generate these repetitive pulses after the initial one Ignition of the vacuum chal-ts track is an oscillator 90 is provided, which is able to at its output terminals 91 repetitive impulses with the desired ' Frequency. The output terminals 91 of the oscillator can be connected in parallel to lamp 75. An auxiliary control switch 92 connects the oscillator shortly after it closes of the control switch 85 with the lamp and thus supplies it the oscillator pulses. The lamp reacts to every voltage pulse with the delivery of a light pulse to the trigger pulse sources 70, whereupon each source 70 has its corresponding Ignition path supplied with a pulse in the desired manner. When the main contact pieces reach their contact position,

the switch 86 opens and separates the lamp 75 from the oscillator so that no more pulses reach the ignition path.

The oscillator 90 can be superfluous if, instead of a triggerable vacuum switching path, a "triggerable

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Low pressure gas train used. The low pressure gas train can have the same structure as the one shown Vacuum interrupter 32, but with the difference that they is not highly evacuated, but gas with a pressure in the micron range contains, e.g. nitrogen at a pressure of 1/10 mm. Such a switching path is normally not in a Then go out the current zero crossing after the discharge, but remain conductive after their ignition until the Main contact pieces 12, 14 touch. When touching the contact the voltage disappears across the primary path, so that it can be extinguished. Because with such a stopping distance No repetition pulses are required, the oscillator 90 is superfluous when using this switching path The gas pressure in the switching section is low enough so that is the mean free path of the gas particles inside the Piston 4o is greater than the distance between the electrodes.

Although in Fig. 1 for each triggerable vacuum holding section ^ 2 only a single ignition gap 54 is shown, it is at AC conditions usually desirable, two spark gaps one for each main electrode. Thus the ignition of the main line due to a rollover the ignition path is facilitated, the ignition path should be arranged at the cathode of the main path. If you have two Provides an ignition line, one near each main electrode, and if one flashes over these two ignition

η St · «« * -

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route initiates, if the main route is to ignite, so is ensures that regardless of which main electrode is the cathode, an ignition gap is ignited in the vicinity of the cathode will.

In Fig * la a triggerable vacuum switch-V is schematically stretch with two. Ignition gaps 54, one for each main electrode, shown. Each ignition gap 54 lies parallel to a separate one Trigger pulse source 70. The pulse sources 70 are normally turned off and are by light pulse signals, "from a common light source such as the lamp 75 according to FIG. 1 via light guide 75 are switched on.

In order to reduce the size of the voltage which the triggerable vacuum switching path must be able to withstand when the switch is open, the embodiment of the invention according to FIG. 2 can be used. In this embodiment, an intermediate contact 100 is provided at each separation point of the switch between the two main: contact pieces 12 and 14; see. There is an insulating gap 102 between the intermediate contact 100 and the movable contact piece 14 when the switch is in its fully open position according to FIG. In this position, the insulating gap 102 is in series with the primary section 50 of the vacuum switching section. The between. The voltage prevailing in the main contact pieces 12 and 14 is therefore divided between the insulating ^{gap 102 and:} the primary path, so that the vacuum or primary path 50 relieves part of the total voltage; is. _ - '- / -_

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-. During a closing process, the 'movable contact piece l4 is lifted * whereby it first touches the intermediate contact 100 and then the stationary contact piece 12. The ignition of the triggerable vacuum holding section is delayed until after the movable contact piece touches the intermediate contact 100. In the embodiment according to PIg. 2 \ ignition device used may be substantially equivalent to that used in Fig. 1 and is therefore shown in the drawing ni.cht.

Although they are also not shown, understand that suitable capacitors or other impedances are connected in parallel to the columns or switching paths of the switch can be used to achieve a desired tension distribution between the lines when the holder is open.

Certain switches require the resistors 30 both during opening and during Closing the switch to use. It is known that the resistors j50 the interruption during an opening process by limiting the rate of rise of the recovery surge. At the counters after 1 and 2 are the resistors j50 during an opening process separated and do not serve the desired reduction the recovery rate during opening. In which In the embodiment according to FIG. 3, however, the resistors are available for this purpose during an opening process. Here each of the main separation points of the contact pairs 11 is through

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a resistance switch 110 connected in parallel is bridged. These resistance switches 110 are designed in such a way that they close approximately simultaneously with the main contact pairs 11. When closed, the resistance switches 110 place the resistors 30 in parallel with the main isolators. While after opening the main switch, the resistance switches remain 110 closed until after the opening of the main separation points a predetermined period of time has elapsed. During this period, the resistors JO bridge the main separation points and limit the rate of rise of the recovery voltage in the desired manner. If the interruption at the main separation points is completed, the resistance switches 110 are opened and interrupt the residual current through the resistors JO.

Resistance switches 110 are in Pig. J schematic shown to facilitate an understanding of the invention.

Essentially in the same way as it was on hand Fig. 1 and 2 was explained in the Ausführungsbeisplel according to Fig.> the triggerable vacuum switching sections ^ 2 at the same time ignited during closing and thereby switched on the resistors JO.

Another embodiment of the invention, in which the resistors 3O used during an opening process is shown in Fig. 4, which is part of the Switch shows in its fully open position. In this embodiment according to FIG. 4, the triggerable vacuum "

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Switching tree 32 is relatively movable instead of fixed electrodes Main electrodes 46, 48, which are brought together via the main or primary section 50 following a rollover.

Pig. 4 a stationary electrode 40 and a vertically movable electrode 46. The movable electrode 46 is mounted on the upper end of a contact rod l46, which freely through the lower end cap 44 and an opening in the contact bridge 15 protrudes. A matching metal bellows 118 forms a seal around the contact rod 146 to maintain the vacuum inside of the switching path 32 to maintain "When the switch is open is, the movable electrode 46 is by means of a schematically shown, the arrangement holding open pawl ■ -120 in held in their position as shown:

The closing of the switch and the ignition of the safety line during the closing will be in the same catfish carried out as explained in connection with FIG. However, in the arrangement according to FIG. 4, the electrodes 46, 4c the switching path after this has been controlled in its conductive state "has been brought together, - instead of in · their position to stand still. At a suitable point of the Closing stroke of the switch, the retaining pawl 120 disengaged, whereupon a closing spring 123 touches the electrode 46 with the stationary electrode 43 pushes upwards.

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To release the pawl 120 at the desired point of the A release spring 121 and serve for the closing stroke of the switch a switching cam, 122 fastened to the contact bridge 15. if the contact bridge 15 reaches a certain point during its upward movement, the cam 122 releases the pawl 121 or releasing spring 121 free. With this solution, the closing spring 125 can move the electrode 46 of the switching path merge quickly with the stationary electrode 43. this effectively keeps the resistance ^ O parallel to the main contact pieces, when the switch is closed and during the initial part of an opening process.

While a switch is opened, the contact bridge 15, after it has traveled a certain distance down, comes into contact with a shoulder 126 on the movable contact rod 146, so that the vacuum switch formed by the triggerable switching path: 32 is opened at a desired point of the opening stroke after the main contact pieces have already separated. Before this opening of the switching. When the switching path j52 is opened, the electric current is interrupted by the resistance ^ O.

Although only a single-phase Sehalter is shown in the drawing is, the invention is suitable, of course. also for multi-phase switches, with multiple marriages in each phase of the

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, BAD ORIGINAL

Circuit an arrangement * which is compatible with any of the in the Arrangements shown in the drawing match, switched •will. One of the arrangements can only switch on the trigger pulse sources 70 of all signal lines at the same time Phases common light source or lamp 70 can be used ^ so that all triggerable Sehaltverbindungen 52 practically simultaneously be ignited. In another execution form Invention, the sustained segments of each phase can be supported controlled separately from those of the other phases. For example can synchronously assign the stopping lines of each phase to that particular phase at a specific point in time Voltage oscillation can be ignited. -

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Claims (11)

Claims 1.) High-voltage switch with several sets of separable contact pieces connected electrically in series, which are all separated when the switch is open and can be moved into a contact position when the switch is closed, and with a voltage-controlling resistor assigned to each contact set, which at a certain point in time during the closing of the switch to the associated contact set can be switched in parallel, thereby geke η η ζ eich η et that a triggerable switching path {j> 2) with a primary electrode pair (46, 48), which form a main path (50) between them, in Series with the associated resistor (3> 0) and a trigger device (54 to 65) is connected, 'which causes a rollover over the main line when a trigger signal is applied, and that while the switch is closed, a device can be actuated which is connected to the Trigger device delivers trigger signals by which before the contact piece sets "(12, l4) in all Sc stopping distances (50, 54) - flashovers can be ignited practically at the same time. 2.) Switch according to claim 1, d a d u r c h g e k e η η -. ζ ei ch η e t that the triggerable switching path (32) a Vacuum holding distance is in which the normal pressure between the Electrodes (46, 48) is less than 10 "mm of mercury. 009840/03 17 3.) Switch according to claim 1, d a d u r c h ge ken n draws, that the triggerable switching path (32) is a low-pressure gas device in which the mean free path the gas particle is larger than the gap distance between the primary electrodes (46, 48). ' 4.) Switch according to claim 1, characterized in that the trigger device is one within the triggerable switching section (32) in the vicinity of the main section "(50") arranged ignition path (54) as well as a device (6-5) for initiating a rollover'over the ignition path on the ground of a trigger signal. 5.) Switch according to claim 1, d ad urch. gek en η - indicates that while the switch is closed, the flashovers via the switching paths (50, 54) can be initiated in the vicinity of the voltage zero point of the source-side network-ground voltage. 6.) Switch according to claim 1, since you r c h ge ken n ζ e i c h η e t that for each pair of separable contact pieces (12, 14) an 'intermediate electrode - (10Q) - is provided which is arranged between the contact pieces when they are full are open so that between the intermediate electrode and a first contact piece and between the intermediate electrode and the other Kpntaktstück a second switch gap (102) is located and the voltage prevailing between the separable contact pieces is divided among the Sehaltern column; is, 0098 407 03 1 7 and that one electrode (48) of the triggerable = switching path (j52) is connected to the intermediate electrode in such a way that the switching path is parallel to the first switch gap (Fig. 2). 7.) Switch according to claim 1, d a d u r e h g e k e η η. draws, that each contact piece set (12, l4) a'-. Resistance switch (110) is assigned, which is in series with the respective resistor (.30) and parallel to the triggerable Switching path (> 2) is switched and in the closed state puts the resistor parallel to the respective contact set, and that a device is provided that the resistor holder during the initial part of an opening process of the - ■ " Keeps the switch closed, which causes the resistance to increase the rate of rise of the recovery voltage surge in the event of a current zero crossing controls during opening, and then the resistance switch opens and thereby the current through the resistor interrupted (Fig. Jj). 8.) switch according to claim 1, d a d u r c h g e k e \ rv n, - .:: shows that both electrodes (46, 48) of the switching path (32) can be moved into and out of a contact position are, and that a control device (120 to 12 ^) is provided is what the electrodes are immediately after the ignition Switching path merges during the closing of the switch (Fig. 4). '. - ■■■ ": ■ 009840/0317 * ^{>? ί} '- y ^ f ßAD ORIGINAL 9 «) Switch? ' according to claim 8, d a u r eh g e k en η ζ ei c h η e t that the electrodes (46, 48) during the initial part of an opening process of the switch are held in their contact position and the resistance (JO) the Rate of rise of the recovery voltage surge with a current zero crossing controls during opening, and that the electrodes (46, 48) are separated during a subsequent part of the opening process and interrupt the current through the resistor. 10.) Switch according to claim 1 ,. characterized in that a device (65) for applying the Trigger signals normally switched off, trigger pulse sources connected to the associated trigger devices of the switching sections (70) and a device (75) which the pulse sources are activated practically at the same time. 11.) Switch according to claim 10, characterized in that the trigger pulse sources (70) can be activated by receiving a certain light signal, and that a light source common to all sources is provided, which generates and emits light energy, to activate the pulse sources, the ₄ simultaneously reaches the pulse sources in the form of light signals and switches them on. 009840/0317