Special-shaped self-breakdown high-voltage gas switch with peak electrode structure
Technical Field
The invention relates to a self-breakdown gas switch in the technical field of high-power pulse driving sources, in particular to a special-shaped self-breakdown high-voltage gas switch with a peak electrode structure.
Background
The technology of the high-power pulse driving source is a scientific technology which rapidly releases energy stored for a relatively long time in a short time through a high-power pulse generator. In recent years, with the development of high power pulse generators in the directions of high repetition frequency, high stability, long service life, and the like, the high power pulse drive source technology has been widely applied in the fields of high energy laser, high power microwave, biomedical, environmental protection, material treatment, and the like.
The switch is used as a core device in the high-power pulse generator and plays a role in connecting the energy storage device with a load, and the characteristics of the switch greatly determine the waveform of an output pulse. The switches are classified into gas switches, magnetic switches, semiconductor switches, and the like. At present, gas switches are generally applied to high-power pulse generators due to high working voltage, strong current capacity, low cost and flexible and various shapes and forms. The gas switches are mainly classified into self-breakdown switches and trigger switches. Compared with a self-breakdown switch, the trigger switch is provided with a trigger pole, the switch structure is complex, the trigger is easy to ablate, and the service life and occasions of the trigger switch are influenced. The self-breakdown switch has an advantage of simple structure, but the switching jitter is large relative to the trigger switch. Based on the self-breakdown gas switch, the research on the self-breakdown gas switch with low jitter, long service life and high stability has important application prospect in the field of high-power pulse power.
For the self-breakdown gas switch, the self-breakdown voltage dispersion is an important factor for judging the working stability of the self-breakdown gas switch. The traditional concept holds that the smaller the roughness of the electrode surface, the smoother the whole electrode, the more stable the electrode breakdown, and the smaller the dispersion of the self-breakdown voltage. However, in previous studies, it was found that in the self-breakdown test, the surface of the gas switch electrode is continuously ablated, and the protrusions and pits are generated. These bumps and pits may change the flatness of the electrode surface, thereby affecting the stability of self-breakdown. Based on this, if increase electrode surface roughness, the electric field on electrode surface can strengthen, and initial electron can concentrate in electrode surface minimums to electrode ablation can concentrate, and the gas switch is more stable, thereby reduces the dispersion of self breakdown voltage.
Wujiawei of SiAnn university of transportation reports a Self-breakdown gas switch as shown in FIG. 1 in the academic paper "Experimental Study of Self-breakdown gas Switches in Cu-W Electrode Spark gaps Switches" [ Jianwei Wu. "Experimental Study of Self-breakdown gas Switches in Cu-W Electrode Spark gaps Switches", Transactions on diagnostics and electric instrumentation, Vol.24,2017 (Experimental Study on copper-tungsten electrodes, dielectric and Electrical Insulation, volume 24, page number: 2056-. The gas switch is rotationally symmetric about NN'. The self-breakdown gas switch consists of an insulating cavity 1, a cathode rod 2, an anode rod 3, a cathode electrode 4 and an anode electrode 5. The insulating cavity 1 is a cylindrical cavity with two end faces and is composed of an insulating cylinder 101, a front insulating end plate 102 and a rear insulating end plate 103. The front insulating end plate 102 is fixedly installed at the left end (end connected with a high-voltage power supply) of the insulating cylinder 101, the rear insulating end plate 103 is fixedly installed at the right end (end connected with a load) of the insulating cylinder 101, and the front insulating end plate 102 and the rear insulating end plate 103 are symmetrical with respect to AA'. The cathode rod 2 and the anode rod 3 are identical in shape and structure and are symmetrical in position with respect to AA'. The cathode electrode 4 is fixed at the right end of the cathode rod 2 and is positioned in the insulating cavity 1, and the anode electrode 5 is fixed at the left end of the anode rod 3 and is positioned in the insulating cavity 1. The specific shape and structure of the insulating cavity 1, the cathode rod 2, the anode rod 3, the cathode electrode 4 and the anode electrode 5 are not described in detail herein. In a 2-ten-thousand pulse experiment, the self-breakdown voltage of the self-breakdown gas switch shown in fig. 1 is about 32.4kV, and the self-breakdown voltage dispersion is larger and is 10.2%. The instability of the self-breakdown voltage of the gas switch is illustrated, and the application of the gas switch in a pulse power device is limited.
Disclosure of Invention
The invention aims to solve the technical problems that the self-breakdown of the conventional self-breakdown gas switch is unstable due to no trigger electrode, the self-breakdown voltage dispersion is large and the like, and provides a special-shaped self-breakdown high-voltage gas switch with a peak electrode structure.
The technical scheme of the invention is as follows: the special-shaped self-breakdown high-voltage gas switch with the peak electrode structure comprises a cathode electrode, an anode electrode, a cathode rod, an anode rod and an insulating cavity. The cathode rod and the anode rod are fixed on the insulating cavity through bolts, and the cathode electrode and the anode electrode are respectively fixed on the cathode rod and the anode rod through threaded holes. The insulating cavity is composed of an insulating cylinder, a front insulating end plate and a rear insulating end plate. The end of the invention connected with a high-voltage power supply (namely, the side of the front insulating end plate) is defined as an input end (left end), and the end of the invention connected with a load (namely, the side of the rear insulating end plate) is defined as an output end (right end).
The insulating cavity is a cylindrical cavity with two end faces and consists of an insulating cylinder, a front insulating end plate and a rear insulating end plate. The insulating cylinder 101 has a length L and a thickness W ═ R2-R1Inner radius of R1And an outer radius of R2(R1<R2) L is generally 8 to 80cm, R1Generally 10-50 cm, and is made of insulating materials. The front insulating end plate and the rear insulating end plate are completely the same in structure and have the radius equal to R2The disc of (2) has a thickness of T. Front stopThe flange end plate is fixedly arranged at the left end of the insulating cylinder, the rear insulating end plate is fixedly arranged at the right end of the insulating cylinder, and the front insulating end plate and the rear insulating end plate are symmetrical relative to BB'. The centers of the front insulating end plate and the rear insulating end plate are drilled with through holes.
The two end faces of the insulating cylinder are uniformly tapped with S (S)>1) A first threaded hole. The first threaded hole has a diameter M (M)<R
2-R
1) The radius of the central line of the first threaded hole is
The left end face of the insulating cylinder is fixedly connected with the front insulating end plate through a screw rod with the diameter equal to M inserted into the first threaded hole, and the right end face of the insulating cylinder is fixedly connected with the rear insulating end plate through a screw rod with the diameter equal to M inserted into the first threaded hole.
The front insulating end plate is a disc made of insulating material and has a radius of R
2The thickness is T, and T is generally 2-10 cm. At a center line radius of
S first through holes are drilled at the positions, the aperture of each first through hole is equal to M, and the front insulation end plate is connected with the left end face of the insulation cylinder through the S first through holes through a screw rod. The center O of the front insulation end plate is drilled with a radius R
3And a second through hole of radius R
4First positioning groove of R
3Generally 0.5 to 5cm, R
4>R
3. The
first positioning groove 1023 has a depth H, which is generally 0.5-1 cm.
The rear insulating end plate and the front insulating end plate are completely the same in shape and structure, and the installation position is symmetrical to the front insulating end plate about a central line BB'. The rear insulating end plate is connected with the right end of the insulating cylinder through a screw.
The anode rod is a round rod with a disc and consists of a left anode round rod, an anode disc and a right anode round rod. The anode disc is made of stainless steel and welded between the left anode round rod and the right anode round rod to connect the left anode round rod and the right anode round rod together. The left anode round rod is L in length1,L1Generally 1-20 cm, and the radius is equal to half of the second through holeDiameter R3. The radius of the anode disc is equal to the radius R of the first positioning groove4The thickness is equal to the depth H of the first positioning groove. The length of the right anode round rod is L2,L2Generally 1-20 cm, and the radius is equal to the radius R of the second through hole3And the left anode round rod penetrates through the second through hole from the right side of the front insulating plate, the anode disc is embedded in the first positioning groove, the left anode round rod is fixed on the front insulating end plate through a bolt, and the left end of the left anode round rod is connected with a high-voltage power supply. The right end of the right anode round rod is tapped with threads and is connected with an anode electrode. The left anode round rod and the right anode round rod can also be a complete round rod, and a radius equal to R is dug in the center of the anode disc3The round rod consisting of the left anode round rod and the right anode round rod is inserted into the through hole in the center of the anode disc and is welded and fixed, thus forming the anode rod.
The cathode rod and the anode rod are identical in shape and structure, and the installation positions are symmetrical about a center line BB'. The cathode rod is a round rod with a circular disc and consists of a left cathode round rod, a cathode circular disc and a right cathode round rod. The disc material is generally stainless steel and is welded between the left cathode round rod and the right cathode round rod. The length of the left cathode round rod is equal to the length L of the right anode round rod2Radius equal to radius R of the third through hole3. Radius of cathode disc equal to R4The thickness is equal to H. The length of the right cathode round rod is equal to the length L of the left anode round rod1Radius equal to R3. The right cathode round rod penetrates through the third through hole from the left side of the rear insulating plate, the cathode disc is embedded in the second positioning groove, the right cathode round rod is fixed on the rear insulating end plate through a bolt, and the right end of the right cathode round rod is connected with a load. The left end of the left cathode round rod is tapped with threads and is connected with a cathode electrode. The left cathode round rod and the right cathode round rod can also be a complete round rod, and a radius equal to R is dug in the center of the cathode disc3The round rod consisting of the left cathode round rod and the right cathode round rod is inserted into the through hole in the center of the cathode disc and is welded and fixed, thus forming the cathode rod.
The anode electrode is of a special-shaped structure and made of any one of stainless steel, copper-tungsten alloy and brass. AnodeThe whole electrode is in a disc shape with a pit on the end face, but the outer side face of the disc is not a regular circular ring but is processed into a circular face protruding outwards. Radius of the disc being R5The maximum thickness of the disc is L3Wherein R is3<R5<R1,L3<L/3. The distance from the left end face and the right end face of the disc along the thickness direction of the disc is L3The line perpendicular to the anode rod of/2 is an anode electrode center line SS ', and the left side of the center line SS' is defined as the left end face of the anode electrode 4, and the right side is defined as the right end face of the anode electrode. The left end face of the anode electrode is provided with a radius equal to R3And a third threaded hole 402 having a depth L5,L5<L3/2. The left end face of the anode electrode is tightly connected with the right end of the right anode round rod through a third threaded hole. The outer ring of the anode electrode is processed into a round surface with the radius of R6The curvature CMD of the circular surface is alpha, wherein R6=L3/2,π/2<α<3 pi/2. Because the radian CMD of the circular surface is between pi/2 and 3 pi/2, the thickness of the central part of the right end surface of the anode electrode is less than L3Thereby forming an anode pit. The radius of the anode pit is R7,R7=R5-R6-R6sin (α - π/2); depth of anode pit is L4,L4=L3-R6-R6cos (a-. pi./2). Ablation of the anode electrode typically occurs at the anode overhang. The anode electrode has a smaller ablation surface, and the anode protruding part is generally smaller and can be approximately considered as a plane.
The anode protruding part is processed into a surface with the roughness N, the electrode surface is processed into a peak structure, and the roughness N is determined according to a surface roughness grade comparison table and is generally 0.8 or 1.6 or 3.2 or 6.3 or 12.5. The protruding part of the anode is generally small, and for the convenience of processing, the right end face of the anode electrode is uniformly processed into a special-shaped face with the roughness of N. The central radius of the anode protruding part is R8,R8=R5-R6(ii) a Width L5,0.05R6<L5<0.2R6. Amplifying an axis K in the anode protruding part (which refers to a connecting line from the inner edge of the anode protruding part to the outer edge of the anode protruding part), and taking the axis K as the axis KIs made up of several peaks. The length of the axis K is L5The peak width is L, the peak height is h, the peak interval is d, and the number of peaks n is equal to L5/(l + d). According to the surface roughness level comparison table, the larger the surface roughness N is, the larger the peak width l is, the higher the peak height h is, the larger the peak interval d is, and the smaller the number N of peaks is (as known from the machining process, N, l, h, d, N are also determined). As the surface roughness N increases, the larger the peak width l and the peak interval d, the smaller the number of peaks N, the fewer points at which breakdown easily occurs, and the more easily the breakdown concentrates on a few peak positions. Meanwhile, the larger the peak height h is, the stronger the electric field of the peak is, and the more easily the breakdown occurs. Consequently through increase electrode surface roughness N, can increase electrode surface electric field, make switch electrode surface electron production, make the switch puncture more stable, reduce from breakdown voltage dispersion, promote switch job stabilization nature.
The cathode electrode and the anode electrode are completely the same in shape, structure and material, and the installation position is symmetrical about the center line BB'. Ablation of the cathode electrode typically occurs at the cathode projection, which is symmetric about centerline BB' to the anode projection. The right side of the cathode electrode is tightly connected with the left end of the cathode rod through a fourth threaded hole.
The working principle of the invention is as follows: the high-voltage direct-current power supply continuously loads high-voltage electric signals to two ends of the switch electrode, and as the voltage increases, the switch electrode is conducted after the self-breakdown voltage of the gas switch is reached, energy is transmitted to a load, the voltage of the two ends of the switch electrode is reduced, and the switch electrode is closed. Then, the high-voltage signal is continuously loaded to two ends of the switch electrode, the switch electrode is continuously conducted and closed, and energy is continuously transmitted to the load. Through processing the electrode surface into the structure of area peak, increase electrode surface electric field makes switch electrode surface electron produce, makes the switch puncture more stable, reduces from the breakdown voltage dispersion.
The invention can achieve the following technical effects:
1. according to the invention, the anode protruding part and the cathode electrode protruding part are processed into the surfaces with the roughness of N, and the electrode surfaces are processed into the structures with the peak, so that the electrode surface electric field is increased, the generation of switch electrode surface electrons is facilitated, the self-breakdown voltage dispersion is reduced, and the switch breakdown is more stable.
2. The invention has simple principle, convenient use and wide application range.
Drawings
FIG. 1 is a general structure diagram of a switch according to the prior art;
FIG. 2 is a general block diagram of the present invention;
FIG. 3 is a left side view of the insulating cylinder of the present invention;
FIG. 4 is a right side view of the front insulating end plate of the present invention;
FIG. 5 is a view of the anode stem structure of the present invention;
FIG. 6 is a view showing the structure of a cathode bar according to the present invention;
FIG. 7 is a schematic view of an anode electrode of the present invention, FIG. 7(a) is a left side view of the anode electrode, FIG. 7(b) is a right side view of the anode electrode, and FIG. 7(c) is a three-dimensional perspective view of the anode electrode;
FIG. 8 is a side view of an anode electrode of the present invention;
fig. 9 is a right side view and an enlarged axial view of an anode projecting portion of the anode electrode according to the present invention, fig. 9(a) is a right side view of the anode projecting portion, and fig. 9(b) is an enlarged axial view of the anode projecting portion.
Detailed Description
The structure and the working principle of the invention are described in detail with the attached drawings as follows:
as shown in fig. 2, the present invention is composed of an insulating chamber 1, an anode rod 2, a cathode rod 3, an anode electrode 4 and a cathode electrode 5. The anode rod 2 and the cathode rod 3 are fixed on the insulating cavity 1 through bolts, the anode electrode 4 is fixed at the right end of the anode rod 2 and is positioned in the insulating cavity 1, and the cathode electrode 5 is fixed at the left end of the cathode rod 3 and is positioned in the insulating cavity 1; the end of the invention connected with the high-voltage power supply is defined as an input end (left end), and the end of the invention connected with the load is defined as an output end (right end).
The insulating cavity 1 is a cylindrical cavity with two end faces and is composed of an insulating cylinder 101, a front insulating end plate 102 and a rear insulating end plate 103. The insulating cylinder 101 has a length L and a wall thicknessIs W ═ R2-R1Inner radius of R1And an outer radius of R2(R1<R2) (see FIG. 3), R1Generally 10-50 cm, and is made of insulating materials. The front insulating end plate 102 and the rear insulating end plate 103 are identical in structure and have the radius equal to R2Of (c) (see fig. 4), with a thickness T. The front insulating end plate 102 is fixedly arranged at the left end of the insulating cylinder 101, the rear insulating end plate 103 is fixedly arranged at the right end of the insulating cylinder 101, and the front insulating end plate 102 and the rear insulating end plate 103 are symmetrical about BB'. The centers of the front insulating end plate 102 and the rear insulating end plate 103 are drilled with through holes.
As shown in fig. 3, both end surfaces of the insulating
cylinder 101 are uniformly tapped with S (S)>1) A first threaded
hole 1011. The first threaded
hole 1011 has a diameter of M (M)<R
2-R
1) The radius of the center line of the first threaded
hole 1011 is
The left end face of the
insulation cylinder 101 is fixedly connected with the front
insulation end plate 102 through a screw rod with the diameter equal to M inserted into the first threaded
hole 1011, and the right end face of the
insulation cylinder 101 is fixedly connected with the rear
insulation end plate 103 through a screw rod with the diameter equal to M inserted into the first threaded
hole 1011.
As shown in connection with FIG. 4, the front
insulator end plate 102 is a disk of insulating material having a radius R
2The thickness is T (see figure 2), and T is generally 2-10 cm. At a center line radius of
S first through
holes 1021 are drilled at the positions, the aperture of each first through
hole 1021 is equal to M, and the front
insulation end plate 102 is connected with the left end face of the
insulation barrel 101 through the S first through
holes 1021 through screws. The center O of the front insulating
end plate 102 is drilled with a radius R
3And a second through-
hole 1022 and having a radius R
4 First aligning groove 1023, R
3Generally 0.5 to 5cm, R
4>R
3. The
first alignment groove 1023 has a depth H (see FIG. 2), which is generally 0.5-1 cm.
As shown in fig. 2, rear insulating end plate 103 is identical in shape and structure to front insulating end plate 102, and is mounted symmetrically to front insulating end plate 102 about center line BB'. The rear insulating end plate 103 is connected to the right end of the insulating cylinder 101 by a screw.
As shown in fig. 5, the anode rod 2 is a disk-shaped rod, and is composed of a left anode rod 201, an anode disk 202, and a right anode rod 203. The anode disc 202 is made of stainless steel, and is welded between the left anode rod 201 and the right anode rod 203 to connect the left anode rod 201 and the right anode rod 203. The left anode rod 201 has a length L1,L1Generally 1-20 cm, and the radius is equal to the radius R of the second through hole 10223. The anode disc 202 has a radius equal to the radius R of the first aligning groove 10234And has a thickness equal to the depth H of the first seating groove 1023. The right anode rod 203 has a length L2,L2Generally 1-20 cm, and the radius is equal to the radius R of the second through hole 10223The left anode rod 201 passes through the second through hole 1022 from the right side of the front insulating plate 102, the anode disc 202 is embedded in the first positioning groove 1023, the left anode rod 201 is fixed on the front insulating end plate 102 through bolts (see fig. 2), and the left end of the left anode rod 201 is connected with a high-voltage power supply. The right end of the right anode round rod 203 is tapped with threads and is connected with the anode electrode 4. The left anode round rod 201 and the right anode round rod 203 can also be a complete round rod, and a radius equal to R is dug in the center of the anode disc 2023The round rod composed of the left anode round rod 201 and the right anode round rod 203 is inserted into the through hole at the center of the anode disc 202 and is welded and fixed, thus forming the anode rod 2.
As shown in fig. 6, the cathode rod 3 is identical in shape and structure to the anode rod 2, and the installation position is symmetrical about a center line BB' (see fig. 2). The cathode rod 3 is a circular rod with a circular disk, and is composed of a left cathode rod 301, a cathode circular disk 302, and a right cathode rod 303. The disc material is typically stainless steel and is welded between the left cathode round bar 301 and the right cathode round bar 303. The length of the left cathode round rod 301 is equal to the length L of the right anode round rod 2032Radius equal to radius R of third through hole 10323. The cathode disk 302 has a radius equal to R4The thickness is equal to H. The length of the right cathode round bar 303 is equal to the length L of the left anode round bar 2011Radius ofIs equal to R3. The right cathode round bar 303 passes through the third through hole 1032 from the left side of the rear insulating plate 103, the cathode disc 302 is embedded in the second positioning groove 1033, the right cathode round bar 303 is fixed on the rear insulating end plate 103 through a bolt (see fig. 2), and the right end of the right cathode round bar 303 is connected with a load. The left end of the left cathode round rod 301 is tapped with threads and connected with the cathode electrode 5. The left cathode round bar 301 and the right cathode round bar 303 can also be a complete round bar, and a radius equal to R is dug in the center of the cathode disc 3023The round rod consisting of the left cathode round rod 301 and the right cathode round rod 303 is inserted into the through hole at the center of the cathode disc 302 and is welded and fixed, thus forming the cathode rod 3.
As shown in fig. 7, the anode electrode 4 is a special-shaped structure, and is made of any one of stainless steel, copper-tungsten alloy and brass. The anode electrode 4 is integrally in the shape of a disc with a concave on the end face, but the outer side face of the disc is not a regular circular ring but is processed into a circular face protruding outwards. As shown in fig. 8, the radius of the disc is R5The maximum thickness of the disc is L3Wherein R is3<R5<R1,L3<L/3. The distance from the left end face and the right end face of the disc along the thickness direction of the disc is L3The line of/2 perpendicular to the anode rod 2 is the center line SS 'of the anode electrode 4, and the left side of the center line SS' is defined as the left end face of the anode electrode 4, and the right side is defined as the right end face of the anode electrode 4. The center of the left end surface of the anode electrode 4 is tapped with a radius equal to R3And a third threaded hole 402, the third threaded hole 402 having a depth L5,L5<L3/2. The left end face of the anode electrode 4 is tightly connected with the right end of the right anode round rod 203 through a third threaded hole 402. The outer side surface of the anode electrode 4 is processed into a round surface with the radius of R6The curvature CMD of the circular surface is alpha, wherein R6=L3/2,π/2<α<3 pi/2. Because the radian CMD of the circular surface is between pi/2 and 3 pi/2, the thickness of the central part of the right end surface of the anode electrode 4 is less than L3Thereby forming anode pits 403. Anode pit 403 with radius R7,R7=R5-R6-R6sin (α - π/2); anode pits 403 have a depth L4,L4=R6-R6 cos(a-π/2)。Ablation of the anode electrode 4 typically occurs at the anode overhang 401. The anode protruding portion 401 (i.e., the most protruding portion on the right end surface of the anode electrode 4 shown in fig. 8, and 2 protruding portions when viewed from the side because the anode electrode 4 is a disk-like shape) is generally small because the ablated surface of the anode electrode 4 is small, and can be considered as a plane.
Referring to fig. 9(a), the anode protruding portion 401 is processed into a surface having a roughness N, and the surface of the anode protruding portion 401 is processed into a peak structure, and the roughness N is generally 0.8, 1.6, 3.2, 6.3, and 12.5, which is determined according to the surface roughness level comparison table. The anode projection 401 has a width L in a right view6The ring of (2). The anode protruding portion 401 is generally small, and for the sake of convenience of processing, the right end face of the anode electrode 4 is processed into a special-shaped face with a roughness of N. The center radius of the anode projection 401 is R8,R8=R5-R6(ii) a Width L6,0.05R6<L6<0.2R6. One axis K in the anode protruding portion 401 (referring to a connecting line from the inner edge of the anode protruding portion 401 to the outer edge of the anode protruding portion 401) is taken for amplification, and the axis K can be regarded as being formed by a plurality of peaks. As shown in FIG. 9(b), the axis K has a length L6The peak width is L, the peak height is h, the peak interval is d, and the number of peaks n is equal to L6/(l + d). According to the surface roughness level comparison table, the larger the surface roughness N is, the larger the peak width l is, the higher the peak height h is, the larger the peak interval d is, and the smaller the number N of peaks is (as known from the machining process, N, l, h, d, N are also determined). As the surface roughness N increases, the larger the peak width l and the peak interval d, the smaller the number of peaks N, the fewer points at which breakdown easily occurs, and the more easily the breakdown concentrates on a few peak positions. Meanwhile, the larger the peak height h is, the stronger the electric field of the peak is, and the more easily the breakdown occurs. Consequently through increase electrode surface roughness N, can increase electrode surface electric field, make switch electrode surface electron production, make the switch puncture more stable, reduce from breakdown voltage dispersion, promote switch job stabilization nature.
As shown in fig. 2, the cathode electrode 5 is identical in shape, structure and material to the anode electrode 4, and is installed at a position symmetrical with respect to the center line BB'. Ablation of cathode electrode 5 generally occurs at cathode projection 501, with cathode projection 501 being symmetrical with anode projection 401 about centerline BB'. The right side of the cathode electrode 5 is tightly connected with the left end of the cathode rod 3 through a fourth threaded hole 502.
A specific example is given below as example 1. Example 1 the insulating cylinder 101 is a cylinder made of plexiglas with an inner radius R120cm, outer radius R225cm and a length L of 20 cm. Two side end faces of the insulating cylinder 101 are uniformly tapped with 8 first threaded holes 1011. The diameter of the first threaded hole 1011 is 8mm, and the radius of the center line of the first threaded hole 1011 is 22.5 cm. The front insulating end plate 102 is a disk made of plexiglass with an outer radius equal to R2The thickness T is 2cm at 25cm, and 8 first through holes 1021 are drilled at the position where the center line radius R is 22.5 cm. The center O of the front insulating end plate 102 is drilled with a radius R3A second through hole 1022 of 0.5cm and radius R4The 2cm first alignment groove 1023 has a depth equal to H0.5 cm. The rear insulating end plate 103 has the same shape and structure as the front insulating end plate 102, and is installed symmetrically with the front insulating end plate 102 about the center line BB'. The anode rod 2 is a round rod with a disc and is made of stainless steel. Left anode rod 201 length L13cm, radius R30.5 cm; length L of right anode rod 20323cm, radius R30.5 cm; anode disc 203 radius R42cm and a thickness H of 0.5 cm. The cathode rod 3 is identical in shape and structure to the anode rod 2, and the installation position is symmetrical about the center line BB'. The anode electrode 4 and the cathode electrode 5 are of special-shaped structures with radius R52cm, width L31.0 cm. The outer side surface of the anode electrode 4 is processed into a round surface with a radius R60.5cm, and 2 pi/3 of circular radian COD. An anode pit 403 is formed on the right end surface of the anode electrode 4. Anode pit 403 radius R71.25 cm; width L40.67 cm. The electrode material is tungsten copper, brass or stainless steel. The three electrodes are respectively processed into nine pairs of electrodes with the roughness N of 0.8, 3.2 and 12.5, wherein each pair of electrodes comprises an anode electrode 4 and a cathode electrodeAnd a polar electrode 5.
In order to prove the characteristics of the invention, through an experimental method, 15 ten thousand pulse experiments are respectively carried out on the special-shaped electrodes of copper, tungsten, brass, stainless steel and the like with different roughness, the self-breakdown voltage is about 30kV, the current is about 2kA, and the total charge transfer amount is about 30C. The self-breakdown voltage dispersion of the special-shaped copper tungsten is 2.95%, 1.62% and 1.16% respectively at 0.8%, 3.2% and 12.5%. The self-breakdown voltage dispersion of the shaped brass is 0.8, 3.2 and 12.5, which are respectively 3.80%, 2.29% and 1.53%. The self-breakdown voltage dispersion of the deformed stainless steels 0.8, 3.2 and 12.5 is 1.42%, 1.19% and 1.12% respectively. It was verified that the self-breakdown voltage dispersion is smaller as the electrode surface roughness N increases. By increasing the electrode surface roughness N, the larger the peak width l and the peak interval d, the smaller the number of peaks N, the fewer points at which breakdown easily occurs, and the more easily the breakdown concentrates on a few peak positions. Meanwhile, the larger the peak height h is, the more stable the switch breakdown can be, the dispersion of the self-breakdown voltage is reduced, and the working stability of the switch is improved.