CN106098264A - A kind of 10kV Multifunctional disaster prevention evil insulator and preparation method - Google Patents

Abstract

The invention provides a multi-functional disaster-proof insulator for 10kV transmission lines and a preparation method thereof. The insulator includes arc-shaped line slot fittings, upward-curved rod-shaped discharge electrodes, composite insulator components, insulating umbrella covers, mandrels, and steel foot fittings. , the composite insulator assembly includes a lower conductive spacer, a metal oxide resistor group, a middle conductive spacer, an insulating spacer and an upper conductive spacer, which are sleeved on the mandrel in sequence and are closely attached to each other. The insulating umbrella cover is connected with the upper conductive pad, and the middle conductive pad is connected with an upwardly curved rod-shaped discharge electrode extending to the outside of the insulating umbrella cover. There is air between the arc-shaped wire groove fittings and the upwardly curved rod-shaped discharge electrode. gap. The insulator can realize the lightning protection and anti-ice flashing functions of 10kV lines at the same time, and take into account the functions of preventing heavy rain, bird droppings, pollution, and falling branches. Investment in the construction of distribution network lines.

Description

A 10kV multifunctional disaster-proof insulator and its preparation method

technical field

The invention belongs to the technical field of electrical engineering, and in particular relates to a 10kV multifunctional disaster-proof insulator and a preparation method thereof.

Background technique

The distribution network line is an important part of the system in the five subsystems of power system generation, transmission, transformation, distribution, and use. It undertakes the important task of distributing electric energy to the load. The low insulation level and the simple grid structure make it unable to protect against direct lightning strikes. In addition, the induced lightning voltage generated by lightning on the conductors also greatly exceeds the insulation level of the distribution lines. According to statistics, in the power grid with a voltage level of 6-35kV, the lightning trip rate remains high, and there are often pole-mounted switches, knife switches, lightning arresters, transformers, bushings and other equipment damaged during lightning activities. When the distribution network line is struck by lightning, flashover discharge of the insulator is very easy to occur, causing the surface of the insulator to be burned by the arc, greatly reducing the insulation level, and in severe cases, it will cause the wire to break (the insulated wire is more likely to be broken by lightning than the bare wire), and the line outage.

On the other hand, due to the joint influence of the strong cold air from the north and the warm and humid air from the southwest, some provinces in southern my country have experienced icing disasters on transmission lines, and because the overall height of the distribution network lines is low, the lines are mainly distributed around the city, and the power supply of the distribution network is stable. Sex is more susceptible to falling branches, bird droppings, dirt, heavy rain, etc. Operational statistics show that insulator flashovers caused by lightning strikes and icing in distribution networks account for 70% of the total distribution network tripping faults. These disaster accidents show that: in order to improve the safe operation conditions of existing transmission lines, carry out professional line disaster prevention technical work, strengthen the research on transmission line anti-lightning tripping, anti-icing flashover, anti-pollution flashover, etc., developed a Distribution network insulators with multiple disaster prevention functions are an important issue that needs to be solved urgently.

The related invention patent 201510376532.X has the following defects and deficiencies in the lightning protection and anti-icing flash composite insulator:

1) The insulator’s functions of preventing bird damage, falling branches, and heavy rain are not considered. Under this type of disaster, the overall insulation performance of the insulator decreases, and the stability of power supply is difficult to guarantee;

2) The size of the umbrella group and the discharge electrode is not optimally designed, and the structural design of the discharge electrode is flawed. During the ice-covered period, there will be bridging between the discharge electrodes, the insulation section will fail, the aging of the arrester valve will increase, and the lightning protection and anti-ice flash effect will decline.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art, and provide a system that can effectively prevent various disasters such as thunder, ice, rainstorm, pollution, bird droppings, etc. Multifunctional disaster-proof insulators for 10kV transmission lines undergoing transformation.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

A multifunctional disaster-proof insulator for 10kV transmission lines, including arc-shaped wire slot fittings and upwardly bent rod-shaped discharge electrodes, a composite insulator assembly, an insulating umbrella cover, a mandrel, and steel foot fittings. The composite insulator assembly includes sequentially The lower conductive spacer, the metal oxide resistance sheet group, the middle conductive spacer, the insulating spacer and the upper conductive spacer, which are set on the mandrel and are closely attached to each other, and the insulating umbrella is wrapped outside the composite insulator assembly. An insulating layer is provided between the composite insulator assembly and the insulating umbrella cover, the arc-shaped wire groove fittings penetrate through the insulating umbrella cover and are threadedly connected with the upper conductive pad, and the steel foot fittings pass through the insulating umbrella cover and the lower conductive pad thread connection, the two ends of the mandrel are respectively connected with the arc-shaped groove fittings and the steel foot fittings, the upper conductive pad and the middle conductive pad are insulating pads, and the middle conductive pad is connected with The upward-bending rod-shaped discharge electrode extending to the outside of the insulating umbrella cover has an air gap between the arc-shaped wire groove fittings and the upward-bending rod-shaped discharge electrode.

The arc-shaped wire slot fittings are umbrella-shaped and cover the upwardly bent rod-shaped discharge electrodes as a whole, that is, the overall extension length of the arc-shaped wire slot fittings is greater than that of the upwardly bent rod-shaped discharge electrodes. There is an inclined distance between the end edge of the arc-shaped wire groove fittings and the upwardly curved end of the upwardly curved rod-shaped discharge electrode.

As a further improvement and supplement to the above technical solution, the present invention adopts the following measures.

The insulating umbrella covers are arranged with umbrella groups at intervals from top to bottom. Along the direction from top to bottom, the diameters of the first two insulating umbrella groups decrease sequentially, and the diameters of the last three insulating umbrella groups decrease sequentially. The protruding length and size of the insulating umbrella cover are smaller than the protruding dimensions of the arc-shaped wire groove fittings and the upward-bending rod-shaped discharge electrodes. On the one hand, the staggered arrangement of umbrella groups increases the creepage distance of insulators, and on the other hand, it can prevent ice bridging between umbrella groups.

The upward-bending rod-type discharge electrode includes a screw rod and an upward-bending electrode rod. One end of the screw rod is connected to the middle conductive pad, and the other end extends to the outside of the insulating umbrella cover. The upward-bending electrode rod is connected to the One end of the screw rod protruding from the outside of the insulating umbrella cover is threaded, and the length of the upwardly bent rod-shaped discharge electrode extending out of the insulating umbrella cover is 80-120mm.

The outer part of the upwardly curved electrode rod is covered with an insulating sleeve, and one end of the upwardly curved electrode rod connecting screw is connected to the insulating sheath and is coated with sealing insulating glue at the junction. Both the insulating sleeve and the insulating glue are made of silicon Rubber material, which has strong corrosion resistance and anti-pollution ability and is easy to combine with insulating shed material, effectively increases the flashover level of the insulator along the surface.

The arc-shaped wire groove fittings have a radius of 150-250 mm, which can reduce the impact of disasters such as heavy rain, ice covering, tree branches falling, sewage bridging, bird droppings, etc. on the insulator umbrella cover, and effectively improve the operation stability of the insulator. The lightning strike discharge gap is formed between the arc-shaped wire groove fittings and the upwardly bent rod-shaped discharge electrode, and the gap distance is 50-100 mm. During the lightning strike process, the air gap breaks down and conducts. Under the action, the high resistance is converted into low resistance, and the lightning current is quickly introduced into the earth to prevent the line from tripping.

Both the steel foot fittings and the arc-shaped wire groove fittings are provided with crimping grooves, and the two ends of the mandrel are respectively crimped in the crimping grooves of the steel foot fittings and the arc-shaped wire groove.

The insulating layer is formed by tightly winding and wrapping an insulating tape outside the composite insulator assembly, and the insulating tape is a glass fiber tape soaked in epoxy resin. The glass fiber tape is impregnated by vacuum pressure, that is, the glass fiber tape is first wrapped, and then impregnated with epoxy resin by vacuum pressure, and becomes an insulating layer after curing. The insulating layer is formed by tightly winding and wrapping 10-20 turns of 0.2-0.5mm glass fiber tape insulating tape, has good insulating performance, and can prevent side flashover of the metal oxide resistance sheet. After vacuum pressure is used to add epoxy resin, the adhesion of the insulating tape is enhanced, there is no internal air bubble, the insulation performance is improved, and the metal oxide resistor sheet is well fixed.

The metal oxide resistor group includes a plurality of metal oxide resistors that are sequentially sleeved on the mandrel and closely attached to each other. The metal oxide resistor group generally adopts 7-10 metal oxide resistors in series, Metal aluminum sheets are added between the metal oxide resistance sheets. The metal aluminum sheet can effectively improve the conductivity of the contact surface of the metal oxide resistor, and during the equipment process, it can buffer the crimping of the metal oxide resistor and prevent the metal oxide resistor from crimping damage.

The lower conductive spacer, the insulating spacer, the middle conductive spacer, the metal oxide resistance sheet, the metal aluminum sheet and the upper conductive spacer all have a disc structure with a through hole in the middle.

The insulating umbrella cover is made of high-temperature vulcanized silicone rubber, and the silicone rubber is a hydrophobic material, which can effectively prevent pollution flashover.

Compared with the prior art, the present invention has the advantages of:

1) The multi-functional disaster-proof insulator used for 10kV transmission lines of the present invention has good performance against lightning, ice, rainstorm, pollution, bird droppings and other disasters. It also has the function of insulation, and most of the working voltage is borne by the insulating pad, the aging process of the metal oxide valve plate is significantly weakened, and the service life is greatly extended;

2) Due to the isolation effect of the insulating pad, even if the metal oxide valve plate deteriorates, it will not affect the normal operation of the line;

3) When the line is struck by lightning to generate overvoltage, the non-linear resistance characteristics of the metal oxide resistor play a role in clamping the overvoltage, preventing the external insulation flashover of the insulator, thereby avoiding the tripping of the line by lightning;

4) The metal oxide resistor also limits the size of the lightning current and reduces the heat generated by the current, thereby avoiding disconnection caused by lightning;

5) A metal aluminum sheet is added between the metal oxide resistors, which can effectively improve the conductivity of the contact surface of the metal oxide resistor, and play a buffer role in the crimping of the metal oxide resistor during the equipment process , to prevent crimping damage of metal oxide resistors;

6) Under lightning overvoltage, air breakdown occurs between the arc-shaped wire groove fittings and the upward-bending rod-shaped discharge electrode, which eliminates the burning of the insulating material on the surface of the insulator by the discharge arc and prolongs the service life of the insulator;

7) The design of the arc-shaped wire slot fittings can effectively prevent the discharge gap and the lower umbrella group from bridging under the conditions of ice coating, heavy rain, bird droppings, tree branches falling, etc., and effectively improve the stability of the insulator operation;

8) The application of silicone rubber material insulating sleeve, insulating glue and glass fiber tape impregnated with vacuum pressure epoxy resin effectively improves the insulating performance of the insulator and prevents flashover on the outer surface and the side of the inner metal oxide resistance sheet; In comparison, the insulation tape of 201510376532.X is not impregnated with vacuum pressure, the existence of internal air bubbles will lead to the occurrence of partial discharge, and the insulation performance will be exacerbated and deteriorated;

9) The composite insulator replaces the original ordinary insulator, which can realize the lightning protection and anti-ice flashing functions of the 10kV line at the same time, and take into account the functions of preventing heavy rain, bird droppings, pollution, and falling branches, and is easy to install without changing the tower structure , It is convenient to transform the existing transmission lines, and can save a lot of investment in the construction of distribution network lines.

Description of drawings

Fig. 1 is the cross-sectional structure schematic diagram of the multifunctional disaster prevention insulator that the present invention is used for 10kV transmission line;

Legend: 1. Arc-shaped wire groove fittings; 2. Insulating shed; 21. Shed; 3. Mandrel; 4. Steel foot fittings; 5. Upward-bending rod-shaped discharge electrodes; 51. Upward-bending electrodes Rod; 52, screw; 6, insulating sleeve; 7, sealing insulating glue; 8, nut; 9, metal oxide resistance sheet group; 91, metal oxide resistance sheet; 10, metal aluminum sheet; 11, upper conductive pad block; 12, insulating pad; 13, middle conductive pad; 14, lower conductive pad; 15, insulating layer.

detailed description

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

As shown in Figure 1, the multifunctional disaster-proof insulator used for 10kV transmission lines of the present invention includes arc-shaped wire slot fittings 1 and upwardly bent rod-shaped discharge electrodes 5, composite insulator components, insulating umbrella sleeves 2, and mandrels 3 , steel foot fittings 4, the composite insulator assembly includes an upper conductive spacer 11, an insulating spacer 12, an intermediate conductive spacer 13, a metal oxide resistor group 9, a metal aluminum sheet 10 and the lower conductive pad 14, the metal oxide resistor sheet group 9 includes a plurality of metal oxide resistor sheets 91 that are sequentially sleeved on the mandrel 3 and are closely attached to each other, and the metal oxide resistor sheets 91 are made of metal aluminum slice 10. The insulating umbrella cover 2 is wrapped on the outside of the composite insulator assembly. An insulating layer 15 is provided between the composite insulator assembly and the insulating umbrella cover 2. The arc-shaped wire groove fitting 1 runs through the insulating umbrella cover 2 and is screwed to the upper conductive pad 11. The steel foot Fitting 4 runs through the insulating umbrella cover 2 and is threadedly connected to the lower conductive pad 14. The two ends of the mandrel 3 are respectively connected to the arc-shaped wire groove fitting 1 and the steel foot fitting 4. The middle conductive pad 13 is connected with a pair of symmetrically arranged On both sides of the insulator and through the upwardly bent rod-shaped discharge electrodes 5 protruding to the outside of the insulating sheath 2 , there is an air gap between the arc-shaped wire groove fittings 1 and the upwardly curved rod-shaped discharge electrodes 5 .

In this embodiment, the insulating layer 15 is formed by tightly wrapping an insulating tape on the outside of the composite insulator assembly, and the insulating tape is a glass fiber tape impregnated with epoxy resin. The insulation layer is tightly wound and wrapped with 10-20 turns of 0.2-0.5mm glass fiber tape insulation tape, which has good insulation performance and can prevent side flashover of metal oxide resistors. After the epoxy resin is added under vacuum pressure, the adhesion of the insulating tape is enhanced, there is no internal air bubble, the insulating performance is improved, and the metal oxide resistance sheet 91 is well fixed.

In this embodiment, the upwardly curved rod-shaped discharge electrode 5 includes an upwardly curved electrode rod 51 and a screw 52. The screw 52 is a steel screw. Stretch out the outside of the insulating umbrella cover 2 and be screwed with the upwardly bent electrode rod 51 . During manufacture, the screw rod 52 is first installed in the radial hole of the middle conductive spacer 13, and then the upper conductive spacer 11, the insulating spacer 12, the middle conductive spacer 13, the metal oxide resistance sheet 91, the metal aluminum sheet 10 , and the lower conductive pads 14 are arranged in sequence along the axial direction and pre-compressed, and then wrapped tightly with insulating tape to form a whole. The steel leg fitting 4 is threadedly connected with a nut 8 for use when installing an insulator. The nut 8 is a commercially available stainless steel nut, which is matched with the steel leg fitting 4 .

The above-mentioned upwardly curved electrode rod 51 is covered with an insulating sleeve 6, and one end of the upwardly curved electrode rod 51 connecting screw 52 is connected to the insulating umbrella cover 2 and is coated with sealing insulating glue 7 at the junction, which can prevent moisture from intruding into the insulator Inside: the sealing insulating glue 7 and the insulating sleeve 6 covered on the surface of the upwardly bent electrode rod 51 can extend the creepage distance of the lower half of the composite insulator and ensure its external insulation level.

In this embodiment, both the arc-shaped wire groove fitting 1 and the steel-leg fitting 4 are provided with crimping grooves, and the two ends of the mandrel 3 are respectively crimped in the crimping grooves of the arc-shaped wire groove fitting 1 and the steel-leg fitting 4 Among them, since the arc-shaped wire groove fitting 1 and the steel foot fitting 4 are firmly crimped on both ends of the mandrel 3, sufficient mechanical load bearing capacity can be ensured when supporting and fixing the transmission wire.

In this embodiment, the upper conductive spacer 11 , the insulating spacer 12 , the middle conductive spacer 13 , the metal oxide resistor 91 , the metal aluminum sheet 10 and the lower conductive spacer 14 are all disc structures with through holes in the middle. The arc-shaped wire groove fitting 1 is a steel processing part, and the steel-leg fitting 4 can be a commercially available steel-foot fitting; Reduce the influence of the lower insulator umbrella cover from heavy rain, icing, falling branches, accumulation of bird droppings, etc., and effectively improve the insulation performance of the insulator.

In this embodiment, the mandrel 3 adopts commercially available epoxy glass fiber drawing rod, and the insulating umbrella cover 2 is made of high-temperature vulcanized silicone rubber. The high-temperature vulcanized silicone rubber is made of methyl vinyl silicone rubber with compounding agent. It is vulcanized at high temperature in the designed mold. The metal oxide resistance sheet 91 can be a commercially available annular zinc oxide resistance sheet, and the upper conductive pad 11, the middle conductive pad 13, the metal aluminum sheet 10 and the lower conductive pad 14 are custom-made annular aluminum processing Parts, the insulating spacer 12 is a ring-shaped epoxy glass fiber processing part. The thickness of the metal aluminum sheet is 1-2mm, which can improve the conductivity of the contact surface of the metal oxide resistor, and play a buffer role in the crimping of the metal oxide resistor during the equipment process.

In this embodiment, the upwardly curved electrode rod 51 of the upwardly curved rod-shaped discharge electrode 5 is a steel processing part, the insulating sleeve 6 is a high-temperature vulcanized silicone rubber product, and the sealing insulating glue 7 is room temperature vulcanized silicone rubber. Silicone rubber material Corrosion resistance, strong anti-fouling ability and easy to combine with insulating shed material, effectively increasing the flashover level of the insulator along the surface.

In this embodiment, the insulating shed 2 is provided with sheds 21 arranged at intervals. Along the direction from top to bottom, the diameters of the first two sheds decrease sequentially, and the diameters of the last three sheds decrease successively. The insulating sheds 2 The overall protruding length and size are smaller than the protruding dimensions of the arc-shaped slot fitting 1 and the upwardly bent rod-shaped discharge electrode 5 . When encountering rain, snow and freezing weather, the arc-shaped wire groove fittings 1, the upwardly curved rod-shaped discharge electrode 5 and the large umbrella skirt 21 above all play a good shielding effect on the middle and small umbrella skirts 21 below, and In the case of icing, the air gap between the arc-shaped wire slot fitting 1 and the upward-curved rod-shaped discharge electrode 5 will not appear to be connected by ice bridging, and the gap distance will not be significantly shortened due to the freezing of the electrodes, which is effective. Prevent the false breakdown of the air gap and the drop of the outer insulation level of the insulator.

When the multifunctional disaster-prevention insulator for 10kV transmission line of the present invention is applied to the transmission line, it is installed on the tower to support and fix the transmission wire. When the line is in normal operation, the composite insulator plays the role of an ordinary insulator to support and fix the power transmission The lead wire and keep good insulation between the lead wire and the ground, and most of the working voltage of the line is borne by the insulating spacer 12; in thunderstorm weather, when a lightning strikes the tower or the wire directly, or the lightning strikes the ground near the line, the direct strike overvoltage caused Or when the induced overvoltage is applied to the composite insulator, the overvoltage will cause the air gap between the arc-shaped slot fitting 1 and the upwardly bent rod-shaped discharge electrode 5 to break down, and the overvoltage will be applied to the metal oxide resistance sheet 91 , the non-linear resistance characteristic of the metal oxide resistor sheet 91 plays a role in clamping the overvoltage, thereby protecting the whole composite insulator from external insulation flashover and avoiding line tripping accidents. The composite insulator has been proved to have good lightning protection and anti-icing effects through trial production and trial production. It also takes into account the functions of preventing heavy rain, accumulation of bird droppings, and falling branches. It can fully meet the design requirements for disaster prevention of 10kV transmission lines.

The above descriptions are only preferred implementations of the present invention, and the scope of protection of the present invention is not limited to the above examples. For those skilled in the art, improvements and transformations obtained without departing from the technical concept of the present invention should also be regarded as the protection scope of the present invention.

Claims (10)

1. a 10kV Multifunctional disaster prevention evil insulator, including:

Compound inslation sub-component, insulation umbrella cover (2), plug (3) and steel foot gold utensil (4), described insulation umbrella cover (2) is wrapped in compound Outside insulator assembly, between described compound inslation sub-component and insulation umbrella cover (2), it is provided with insulating barrier (15)；

It is characterized in that:

Described compound inslation sub-component includes being sheathed on upper conductive cushion block (11), the insulation that plug (3) above and is mutually close to successively Cushion block (12), middle conductive cushion block (13), metal oxide resistance group (9) and lower conductive cushion block (14)；

Described metal oxide resistance group (9) includes multiple metal oxide resistance being sheathed on successively on plug (3) (91), it is provided with metal aluminium flake (10) between described metal oxide resistance (91)；

Described middle conductive cushion block (13) connects to have runs through the rod type the being bent upwards electric discharge electricity extending out to insulation umbrella cover (2) outside Pole (5)；

Also include that circular arc type wire casing gold utensil (1) runs through insulation umbrella cover (2) and is connected with upper conductive cushion block (11), described circular arc molded line Groove gold utensil (1) is umbrella and entirety covers the rod type sparking electrode (5) being bent upwards, the two ends of described plug (3) respectively with circle Camber wire casing gold utensil (1) and steel foot gold utensil (4) connect；

The air gap is left between described circular arc type wire casing gold utensil (1) and the rod type sparking electrode (5) being bent upwards.

10kV Multifunctional disaster prevention the most according to claim 1 evil insulator, it is characterised in that: circular arc type wire casing gold utensil (1) Overall extension elongation size stretches out size, circular arc type wire casing gold utensil (1) end more than the rod type sparking electrode (5) being bent upwards The end that edge and the rod type sparking electrode (5) being bent upwards are bent upwards leaves one section of distance tilted.

10kV Multifunctional disaster prevention the most according to claim 1 and 2 evil insulator, it is characterised in that: circular arc type wire casing gold utensil (1) radius is 150-250mm, described circular arc type wire casing gold utensil (1) and be bent upwards between rod type sparking electrode (5) composition thunderbolt Discharging gap, clearance distance is 50-100mm.

10kV Multifunctional disaster prevention the most according to claim 1 evil insulator, it is characterised in that the rod type being bent upwards described in: Sparking electrode (5) has a pair, is symmetricly set on insulator both sides.

10kV Multifunctional disaster prevention the most according to claim 1 evil insulator, it is characterised in that: described insulation umbrella cover (2) sets Having spaced apart full skirt (21), along from top to bottom direction, the full skirt umbrella footpath on rod type sparking electrode (5) being bent upwards depends on Secondary reduction, the full skirt umbrella under rod type sparking electrode (5) being bent upwards is through being sequentially reduced, and insulation umbrella cover (2) entirety stretches out length What degree size was respectively less than circular arc type wire casing gold utensil (1) and the rod type sparking electrode (5) that is bent upwards stretches out size.

10kV Multifunctional disaster prevention the most according to claim 5 evil insulator, it is characterised in that be bent upwards rod type described in: and put Electricity electrode (5) stretches out a length of 80-120mm of insulation umbrella cover (2).

7. according to the 10kV Multifunctional disaster prevention evil insulator described in claim 1 or 4, it is characterised in that be bent upwards rod described in: Type sparking electrode (5) includes screw rod (52) and the electrode bar (51) being bent upwards, described screw rod (52) one end and middle conductive pad Block (13) connects, and the other end runs through the outside of the umbrella cover (2) that extend out to insulate, described in the electrode bar (51) that is bent upwards and described spiral shell Bar (52) stretches out the outside threaded one end of insulation umbrella cover (2) and connects.

10kV Multifunctional disaster prevention the most according to claim 7 evil insulator, it is characterised in that the electrode being bent upwards described in: The outer cover of rod (51) is provided with insulation sleeve (6), and the electrode bar being bent upwards (51) connects one end and the insulation umbrella cover 2 of screw rod (52) Connect and scribble sealed insulation glue (7) in intersection.

10kV Multifunctional disaster prevention the most according to claim 1 evil insulator, it is characterised in that: described insulating barrier (15) is by absolutely Marginal zone compact winding is wrapped in composite insulator component external and is formed, and insulating tape is the glass fiber tape of epoxy resin dipping, glass Fiber band uses vacuum pressure impregnation to form.

10. the preparation method of 10kV Multifunctional disaster prevention evil insulator described in a claim 7, it is characterised in that:

First screw rod (52) is arranged in the radial hole of middle conductive cushion block (13), then by upper conductive cushion block (11), cross-over block (12), middle conductive cushion block (13), metal oxide resistance (91), metal aluminium flake (10), lower conductive cushion block (14) are vertically It is arranged in order and pre-pressing, is rolled into an entirety with insulating tape compact winding afterwards；

Described insulating tape is the glass fiber tape of epoxy resin dipping, is first wrapped glass fiber tape, then uses vacuum pressure impregnation Epoxy resin, then becomes insulating barrier (15) after solidification.