RU2254652C2 - Controlled gas switch - Google Patents

Abstract

FIELD: switching engineering.

SUBSTANCE: proposed controlled gas switch that can be used in electrodynamic installations for switching energy over from storage to load is started by means of gas supply system which feeds gas to electrode gap communicating with external gas source; electric strength of gas within its source is much lower than that in electrode gap. Gas can be supplied through holes made in one of or both switch electrodes. Gas jet may be directed perpendicular to switch axis.

EFFECT: enlarged control range and simplified design of switch.

4 cl, 3 dwg, 1 tbl

Description

The present invention relates to switching equipment and can be used in various electrophysical installations, in high-voltage test installations for switching the source energy to the load.

A typical switch circuit contains two electrodes. One electrode is connected to a voltage source, the second electrode is connected to a load. To transfer energy from the source to the load, you must start the switch. The switch is started as a result of the influence of some factor on its interelectrode gap, under which the condition E> E _{P is created} , where E _P is the electric strength of the gap, E is the field strength in the gap. The specified condition can be met with an increase in E or a decrease in E _P. In accordance with this approach, switches are divided into two types:

1) switches controlled by the principle of reducing the electrical strength of the switch _EP ;

2) switches controlled by the principle of increasing field strength in the gap E.

To date, there are several ways to reduce the value of E _P.

These include trigatrons, spark relays, the use of an electron beam, a high-power laser, a magnetic field [1-3], and a plasma jet [4]. With almost all methods for starting the switch, the control range of the switch (except for starting the switch with a plasma jet) is K = U _st / U _p ≈ 2, where V _st is the static breakdown voltage of the switch electrode gap, and U _p is the minimum voltage at which a discharge is formed. Despite the good starting characteristics of the switches, their use is complicated by additional elements (expensive laser, the need for an electron or ion gun, etc.) and their complexity in layout.

Closest to the proposed technical essence is a managed switch [4] (prototype), in which the control range is K> 2. The switch is launched by supplying a plasma jet formed by means of a discharge in the capillary of the electrode into the interelectrode gap. The switch contains two electrodes. In one of the electrodes along its axis, a ceramic tube is used as a capillary, open on the discharge gap side and closed on the opposite side. Inside the tube is the ignition electrode. The ignition electrode is connected to an ignition circuit that generates a high voltage pulse (15 kV). Auxiliary discharge is carried out on the inner surface of the ceramic tube from the ignition electrode to the main one. Since the diameter of the capillary is small, the discharge plasma quickly fills the volume of the capillary and enters the main gap under pressure, which ultimately leads to the operation of the switch.

The disadvantage of this method and device, which is chosen as the prototype, is the presence of a ceramic capillary, which with a large number of operations will be destroyed, since the temperature of the ignition jet is ~ 3000 K. In addition, to solve many problems, it is desirable to expand the control range of the switch without rebuilding it.

The present invention is aimed at solving the problem of expanding the control range of the switch and simplifying its design.

To solve this problem, as in the prototype, start switch is carried out by reducing the electric strength E _P interelectrode gap. In contrast to the prototype, a decrease in E _P is due to the injection of a gas jet into the interelectrode gap of the switch, the electric strength of which is lower than the electric strength of the gas located in the interelectrode gap of the switch.

The problem is also solved by the fact that in a controlled gas switch containing two electrodes separated by a gas gap and a start system, according to the invention, the start system is made in the form of a system for supplying gas to the interelectrode gap in communication with an external gas source.

In this case, the gas supply system can be made in the form of at least one through hole in one of the electrodes, which is connected by a dielectric tube to an external gas source.

For faster "bridging" between the electrodes, the gas supply system can be made in the form of through holes in two electrodes connected by dielectric tubes to an external gas source.

In addition, the gas supply system can be made in the form of a pipe connected to an external gas source, which has a gap for supplying a gas stream perpendicular to the axis of the switch, while the pipe gap should be no less than the length of the interelectrode gap of the switch.

It is known that the electric strength of gases differs significantly from each other, for example, such results are given in [5] (see table).

E / E values of _air relative electric strength for various gases Gas E / E _ride Relative electric strength C ₂ H ₅ Cl 1.22 1.23 Sf ₆ 2.22 2,3 CHCl ≥ 4.15 4.24 CCl ≥5.9 6.36 Ne 0.17 ~ 0.14

It must be added that the Ne + Ar ₂ mixture [5] has lower strength than pure Ne.

The present invention has significant differences and novelty in that the switch is launched by injecting gas into the interelectrode gap.

The invention is further explained in the description of examples of its implementation and drawings, in which

figure 1 - diagram of a switch according to the invention with a hole in one of the electrodes for injection of gas into the interelectrode gap;

figure 2 is the same device with holes in two electrodes;

3 is a diagram of a switch according to the invention with gas injection perpendicular to the axis of the switch.

In the interelectrode gap of the gas switch according to the invention, a jet of gas, for example Ne, is injected whose electric strength is much lower than the strength of the air with which the interelectrode gap is filled. Under the influence of the injected gas, the electric strength between the electrodes of the switch E _p decreases sharply and the switch starts up.

The controlled gas switch contains two arbitrary shaped electrodes 1, 2, one of the electrodes 1 is connected to a direct current source 3, the other to a load 4, and a gas supply system in the interelectrode gap, made in the form of an opening 5 in the electrode 2, which is connected by a dielectric tube 6 with an external gas source 7.

Another embodiment of the gas supply system is shown in FIG. 2, where holes 5, 8 are made in the electrodes 1, 2 for supplying a gas jet from an external gas source 7 through dielectric tubes 6, 9, respectively, into the interelectrode gap.

Figure 3 shows another embodiment of a gas supply system comprising a dielectric tube 10 connected to an external gas source 7 having an injection slit for supplying gas perpendicular to the axis of the switch, the length of the gap L _{1 is} greater than or equal to the length L of the interelectrode gap.

The device operates as follows. In the initial state (figure 1), a voltage is applied to the electrodes of the switch 1 and 2, which is lower than the static breakdown voltage of the gap of the switch and the switch does not work. At a certain point in time, to start the switch from the gas source 7, through the tube 6 through the hole 5 in the electrode 2, gas is injected into the interelectrode gap of the switch under pressure. Due to the gas pressure and the small hole 5 in the electrode 2, the gas jet quickly fills the gap between the electrodes 1 and 2. Since the gas jet between the electrodes has low electric strength, this greatly facilitates its breakdown. Breakdown of the interelectrode gap occurs under high overvoltage. Such a launch system does not change the physical processes inherent in a breakdown in a gas.

If the hole 7 is made in the electrode 7 (FIG. 2), as in the electrode 2, and is connected by a pipe 9 to the gas source 7, then in this case there will be a more rapid “bridging” between the electrodes 1 and 2 and thereby the switching time is reduced.

An even shorter switching time can be achieved in the design of the switch shown in figure 3. Here, the gas is injected into the gap between the electrodes 1 and 2 in the direction perpendicular to the axis of the switch along the tube 5, which has a gap, the gap being such that its length L ₁ is equal to or greater than the length of the interelectrode gap L of the switch. With such an injection of gas, “bridging” by gas occurs more quickly than in the structures described above.

It should be noted that the proposed method for starting the switch can be used to start gas switches, in which the electrodes and gas are under pressure. However, in this case, the design of the switch is complicated and gas replacement is required after each operation.

Thus, the proposed method for starting the switch allows to significantly increase the control range of the switch and simplify the design of the switch.

Sources of information

1. G.A.Mesyats. Generation of powerful nanosecond pulses / Moscow, Izd. Soviet Radio, 1974.

2. V.V. Kremnev, G.A. Month. Methods of Multiplication and Transformation of Pulses in High-Current Electronics / Novosibirsk, Nauka, Siberian Branch, 1987.

3. Abstracts of a joint meeting of the sections of scientific councils of the USSR Academy of Sciences “Scientific foundations of electrophysics and electric power” and “Problems of powerful pulsed energy” Tomsk, November 27-28, 1986.

4. N.I. Falkovsky. Controlled plasma-jet discharger for switching large pulsed currents, PTE, No. 3, 1973.

5. J. Mead, J. Kregs. Electrical breakdown in gases / Foreign literature, Moscow, 1960, p. 325, 112-113, 370-371.

Claims (4)

1. A controlled gas switch containing two electrodes separated by a gas gap, and a start-up system made in the form of a gas supply system into the interelectrode gap, which is connected to an external gas source, characterized in that the electric strength of the gas in the source is lower than the electric strength of the gas located in the interelectrode gap. 2. The controlled gas switch according to claim 1, characterized in that the gas supply system in the interelectrode gap is made in the form of at least one through hole in one of the electrodes, which is connected by a dielectric tube to an external gas source. 3. The controlled gas switch according to claim 1, characterized in that the gas supply system in the interelectrode gap is made in the form of through holes in both electrodes, which are connected by dielectric tubes to an external gas source. 4. The controlled gas switch according to claim 1, characterized in that the gas supply system is made in the form of a pipe that is connected to an external gas source and has a slot for supplying a gas stream perpendicular to the axis of the switch, the length of which is not less than the distance between the electrodes.

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