CN106099645B - Multi-stage gas switch with corona gap - Google Patents

Abstract

The invention discloses a kind of multistage gas switch containing corona gap, additional triggering system is needed for solving existing multistage gas switch, the baroque technical problem of switching system is caused.Technical scheme is made up of corona gap and over-voltage breakdown gap two parts.Sulfur hexafluoride gas is filled in switch.When switch ends voltage reaches predeterminated level, corona gap preferentially punctures, and over-voltage breakdown gap then punctures.Corona gap has good job stability, can stably Triggered Multi-stage, run multiple-pole switch low jitter.Therefore, the multiple-pole switch containing corona gap, can the stable operation under conditions of external trigger system is not added with, enormously simplify switching system, and reduce switching system volume.

Description

Multi-stage gas switch with corona gap

technical field

The invention relates to a multistage gas switch, in particular to a multistage gas switch with a corona gap.

Background technique

In the field of pulse power technology, switching technology has a particularly important position. It determines the output characteristics of the pulse power device, and is even the key to the success of the pulse power system. The gas switch is a switch that realizes on and off through the generation and dissipation of plasma flow. It has been widely used in the field of pulse power because of its high working voltage, strong current capacity, good repetition frequency stability, and long working life. At present, high voltage and high repetition frequency are important development directions of gas switches. However, when there are special requirements on the volume and weight of the pulse power device, the structure and weight of the gas switch are also restricted.

Refer to Figure 1. The document "Rimfire: A Six Megavolt Laser-Triggered Gas Filled Switch for PBFA II Proceedings of the Fifth IEEE Pulse Power Conference in 1987, pages 262 to 265" discloses a multi-level switch with a laser-triggered gap. The multi-level switch with laser triggering gap includes head-end grading plate 1, end grading plate 3, first electrode 4, first insulator 5, second electrode 6, second insulator 7, third electrode 8 and insulating support 9 . The first electrode 4 is a perforated ball electrode, the second electrode 6 is a ball electrode, and the third electrode 8 is a disc electrode. The first electrode 4 and the second electrode 6 are supported by the first insulator 5 to form a laser trigger gap; every two third electrodes 8 are supported by the second insulator 7 to form an overvoltage breakdown gap. A hole is opened in the center of the first electrode 4 to introduce laser light. When the laser reaches the trigger gap, the trigger gap breaks down preferentially, and the overvoltage gap breaks down subsequently. The electrode spacing of the laser trigger gap is 45 mm. The electrode spacing of the subsequent cascaded 15 levels is 9mm overvoltage breakdown gap. A KrF laser and a laser guiding light path are used as the trigger system. The KrF laser can emit laser light with a full width at half maximum of 22ns and a single pulse energy of 30mJ. In a sulfur hexafluoride environment of 4.48atm, the breakdown voltage of this multilevel switch with a laser-triggered gap can reach 5MV. The standard deviation of the breakdown time is 1 ns. Although a multi-level switch with a laser trigger gap can achieve high voltage and low jitter operation, it requires an additional trigger system, resulting in a complex structure and bulky switch system.

Contents of the invention

In order to overcome the disadvantage that the existing multi-stage gas switch requires an external trigger system, resulting in a complex structure of the switch system, the invention provides a multi-stage gas switch with a corona gap. The multi-stage gas switch is composed of corona gap and overvoltage breakdown gap. The switch is filled with sulfur hexafluoride gas. When the voltage across the switch reaches a predetermined level, the corona gap breaks down preferentially, and the overvoltage breakdown gap breaks down subsequently. The corona gap has good working stability, which can stably trigger the multi-level switch and make the multi-level switch operate with low jitter. Therefore, the multi-level switch with corona gap can operate stably without an external trigger system, which greatly simplifies the switching system and reduces the volume of the switching system.

The technical solution adopted by the present invention to solve the technical problem is: a multi-stage gas switch with a corona gap, which is characterized in that it includes a head equalizing plate 1, a pull rod 2, an end equalizing plate 3, a first electrode 4, The first insulator 5 , the second electrode 6 , the second insulator 7 and the third electrode 8 . The first electrode 4 is in the shape of a circular knife edge, and the tip of the knife is rounded. The second electrode 6 is a plate electrode, the third electrode 8 is a disk electrode, and the edge of the first insulator 5 is grooved. The first electrode 4 and the second electrode 6 are placed opposite to each other, and they are supported by the first insulator 5 to form a corona gap; every two third electrodes 8 are placed opposite to each other and supported by the second insulator 7 to form an overvoltage breakdown gap. A uniform electric field is formed between the pressure equalizing plate 1 at the head end and the equalizing plate 3 at the end, which avoids the interference of the external electric field on the inside. The pressure equalizing plate 1 at the head end and the pressure equalizing plate 3 at the end have holes along the circumferential direction for inserting the pull rod 2 . There are threads at both ends of the pull rod 2, and the threads are exposed outside the pressure equalizing disc. Install nuts at both ends of the tie rod 2 during assembly, and change the distance between the pressure equalizing plate 1 at the head end and the pressure equalizing plate 3 at the end by adjusting the tightness of the nuts, and then compact and fix all electrodes and insulators.

304 stainless steel is used for the head-end pressure equalizing plate 1 , the end pressure equalizing plate 3 , the first electrode 4 , the second electrode 6 and the third electrode 8 .

The material of the pull rod 2 is nylon 1010.

The material of the first insulator 5 and the second insulator 7 is any one of MC nylon or polyimide.

The beneficial effect of the invention is that: the multistage gas switch with corona gap is composed of corona gap and overvoltage breakdown gap. The number of switch stages is adjustable. The first electrode takes the shape of an annular blade. The electric field is higher at the tip of the knife. The edge of the disk electrode is ellipsoidal. Ellipsoidal edges create a quasi-uniform field. During the charging process of the switch, due to the high electric field at the tip of the first electrode, a local self-sustained discharge, that is, a corona layer, can be formed at the tip of the knife before the plasma discharge channel is formed. The corona layer weakens the electric field near the tip of the knife, inhibits the generation of effective seed electrons, and then inhibits the occurrence of pre-breakdown. As the charging voltage increases, the field strength around the corona layer gradually increases, and gradually develops towards the second electrode. If and only when the voltage reaches a specified level, effective seed electrons can be generated to form a plasma discharge channel and cause the switch to break down. During the plasma dissipation process, the heat in the plasma channel can be conducted to the disk electrode through heat exchange. This greatly increases the insulation recovery speed of the gas, thereby increasing the operating frequency of the switch. Under the condition of no external trigger system and gas blowing system, the breakdown voltage of the multi-stage gas switch with corona gap can reach megavolt level, and the working frequency can reach hundreds of hertz.

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Fig. 1 is a schematic structural diagram of a multi-level gas switch with a laser trigger gap in the background technology.

Fig. 2 is a structural schematic diagram of a multi-stage gas switch with a corona gap in the present invention.

Fig. 3 is a waveform diagram of the comb voltage corresponding to the multi-stage gas switch with corona gap according to the embodiment of the present invention.

In the figure, 1-head equalizing plate, 2-tie rod, 3-end equalizing plate, 4-first electrode, 5-first insulator, 6-second electrode, 7-second insulator, 8-third Electrode, 9 - insulating support.

detailed description

The following embodiments refer to Figures 2-3.

The multi-stage gas switch with corona gap of the present invention includes a head-end equalizing plate 1, a pull rod 2, an end equalizing plate 3, a first electrode 4, a first insulator 5, a second electrode 6, a second insulator 7 and a third Electrode 8. The first electrode 4 is in the shape of a ring blade, the second electrode 6 is a plate electrode, and the third electrode 8 is a disk electrode. The first electrode 4 and the second electrode 6 are placed opposite to each other, and they are supported by the first insulator 5 to form a corona gap; every two third electrodes 8 are placed opposite to each other and supported by the second insulator 7 to form an overvoltage breakdown gap. A uniform electric field can be formed between the head-end pressure equalizing plate 1 and the end pressure equalizing plate 3, which avoids the interference of the external electric field to the inside. The pressure equalizing plate 1 at the head end and the pressure equalizing plate 3 at the end have holes along the circumferential direction for inserting the pull rod 2 . There are threads at both ends of the pull rod 2, and the threads are exposed outside the pressure equalizing disc. Install nuts at both ends of the tie rod 2 during assembly, and change the distance between the pressure equalizing plate 1 at the head end and the pressure equalizing plate 3 at the end by adjusting the tightness of the nuts, and then compact and fix all electrodes and insulators.

304 stainless steel is used for the head-end equalizing plate 1 , the end equalizing plate 3 , the first electrode 4 , the second electrode 6 , and the third electrode 8 . The material of pull rod 2 adopts nylon 1010. The material of the first insulator 5 and the second insulator 7 is any one of MC nylon and polyimide.

The corona gap: take the first-level corona gap, which is located at the head end of the switch and close to the cathode. Wherein, the diameter of the first electrode 4 is 100 mm, the thickness of the blade is 1 mm, and the tip of the blade is rounded. The thickness of the first insulator 5 is 18mm. Grooves are carved on the edge of the first insulator 5 to increase the creepage distance. The distance from the tip of the knife to the second electrode 6 is 15 mm.

The overvoltage breakdown gap mentioned above: 6 grades of overvoltage breakdown gaps are used. There are 5 third electrodes 8 in total, all of which have a diameter of 120 mm. The thickness of the second insulator 7 is 11 mm. The shortest distance between the edges of two facing third electrodes 8 is 5 mm.

The diameters of the pressure equalizing disc 1 at the head end and the equalizing disc 3 at the end are both 232mm. Open 8 tie rod holes evenly along the circumference direction with a diameter of 180mm. The length of the pull rod 2 is 115mm, and both ends are tapped with M10 threads. Breakdown voltage jitter is defined as the ratio of the standard deviation of the breakdown voltage to the mean. Under the environment of sulfur hexafluoride gas with an absolute pressure of 5 atm, the switch can work stably at a frequency of 100 Hz, the breakdown voltage reaches 1.1 megavolts, and the breakdown voltage jitter is less than 2%.

Claims (4)

1. a kind of multistage gas switch containing corona gap, it is characterised in that：Including the equal platen of head end (1), pull bar (2), end Equal platen (3), first electrode (4), the first insulator (5), second electrode (6), the second insulator (7) and the 3rd electrode (8)；Institute The first electrode (4) stated is endless knife tooth shape, and point of a knife does rounding processing；Described second electrode (6) is plate electrode, described 3rd electrode (8) is disc electrode, described the first insulator (5) edge cutting；First electrode (4) and second electrode (6) phase To placing, both are supported by the first insulator (5), constitute corona gap；The electrode (8) of each two the 3rd is staggered relatively, by second Insulator (7) is supported, composition over-voltage breakdown gap；The equal platen of the equal platen of head end (1) and end (3) forms uniform electricity between the two , it is to avoid external electrical field is to internal interference；Along the circumferential direction perforate on the equal platen of the equal platen of head end (1) and end (3), is used To insert pull bar (2)；There is screw thread at pull bar (2) two ends, and screw thread is exposed on the outside of equal platen；Spiral shell is installed at pull bar (2) two ends during assembling Mother, and the equal platen of head end (1), end equal platen (3) spacing are changed by adjusting nut elasticity, and then by all electrodes and absolutely Edge is compacted, fixed.

2. the multistage gas switch according to claim 1 containing corona gap, it is characterised in that：The equal platen of described head end (1), the material of the equal platen in end (3), first electrode (4), second electrode (6) and the 3rd electrode (8) uses 304 stainless steels.

3. the multistage gas switch according to claim 1 containing corona gap, it is characterised in that：Described pull bar (2) material Material uses nylon 1010.

4. the multistage gas switch according to claim 1 containing corona gap, it is characterised in that：The first described insulator (5) and the second insulator (7) material using MC nylon or polyimides any one.