CN103474144B - Metal shell cast bus and preparation method thereof - Google Patents

Abstract

The invention discloses a cast bus bar with a metal shell and a manufacturing method thereof. The cast metal busbar includes: multiple standard unit segments; and connecting components; any one of the standard unit segments includes: inner conductor; metal shell; intermediate insulating layer; the connecting components include: inner connecting components; outer connecting components; Insulation. In addition, it also discloses a manufacturing method of the cast bus bar with metal casing. Through the above technical proposal, the invention makes the assembly of the metal casing cast busbar more convenient, greatly shortens the design and production cycle, and saves costs. In addition, the external connection component in the connection component is not only a mold but also bears mechanical stress, and there is no need to demould when pouring insulating materials, and it can be grounded during use, making the operation safer and more reliable.

Description

Casting bus bar with metal casing and manufacturing method thereof

technical field

The invention relates to the field of metal-enclosed busbars in power transmission systems, in particular to a metal-cased cast busbar and a manufacturing method thereof.

Background technique

Metal-enclosed busbar products are indispensable basic equipment in power transmission systems. They connect generator outlets with transformers, circuit breakers, and transformer cabinets, and are widely used in various power plants and substations such as hydropower, thermal power, wind power, and nuclear power. And the power distribution system of large industrial and mining enterprises.

Traditional products are mainly divided into two categories: common box closed busbar and offline closed busbar. The former is mainly used in small-capacity units and plant branch circuits, while the latter is mainly used in large-capacity units and main circuits. These two categories of products have various branches and improved products respectively, and their insulation medium is air, even the insulation medium of the newly emerging forced air-cooled isolated phase-enclosed busbars used in larger capacity units is also air.

Although in the busbar products whose insulating medium is gas, some use sulfur hexafluoride gas with excellent insulating properties to replace air, which improves the withstand voltage level of the product and reduces the size of the product, but in practical applications it is necessary to use micro The positive pressure system prevents external gas from entering the inner conductor, and after a period of time after the micro positive pressure system is inflated, the gas will leak completely. It is necessary to monitor and start the micro positive pressure system at any time to replenish the gas, otherwise, once the external gas invades, it will cause the busbar The insulation performance of the insulation is low, and it is not easy to make adaptive adjustments according to the magnitude of the current, and the cost is high.

The resin layer of the epoxy resin cast busbar not only bears the role of electrical main insulation, but also bears the role of bearing mechanical stress. The traditional cast bus bar is a three-phase cast integrated structure. Products with low voltage levels do not need casings, that is, no magnetic field shielding; products with high voltage levels usually have metal casings, but the metal casings seal the three-phase conductors together, which is equivalent to The shielding effect of the magnetic field of the metal shell of the traditional common-box enclosed busbar structure is weak. Therefore, there is no electromagnetic shielding structure between the three phases, and the conductor current will produce a proximity effect. No matter whether there is a shell structure or not, the induced magnetic field outside the cast busbar cannot be ignored, and as the conductor current increases, its current-carrying capacity is increasing. When a large current develops, it will also be restricted by external magnetic field factors.

Contents of the invention

In order to solve the problems of the prior art, the present invention provides a cast metal busbar on the one hand, which includes: a plurality of standard unit sections; and a connecting component connected to any two adjacent standard unit sections; wherein, any One of the standard unit segments includes: an inner conductor; a metal shell, which is sheathed on the circumferential outside of the inner conductor; Insulation layer; wherein, the connection assembly includes: an internal connection assembly, connected to the inner conductors of two adjacent standard cell segments so that the inner conductors of the two adjacent standard cell segments are connected; a first method is provided flange, a second flange and an external connecting assembly of the connecting shell, the first flange and the second flange are respectively sleeved on the metal shells of two adjacent standard unit sections, and the connecting shell Each surface is respectively fixedly connected between the first flange and the second flange so as to connect the metal shells of two adjacent standard unit segments; and filling the insulating material in the casting form The intermediate connection insulating layer formed between the internal connection component and the external connection component.

In the cast metal busbar as described above, preferably, the internal connection assembly includes a connecting plate and bolts; both ends of the connecting plate are respectively connected to the inner conductors of two adjacent standard unit sections, and the bolts The two ends of the connecting plate are respectively fixed on the inner conductor.

In the casting bus bar with a metal shell as described above, preferably, the connection shell includes an upper top metal plate, a front side metal plate, a lower side metal plate and a rear side metal plate; the upper top metal plate, the front Two ends of the side metal plate, the lower side metal plate and the rear side metal plate are respectively connected to the first flange and the second flange by bolts.

In the cast busbar with a metal casing as described above, preferably, the standard unit section further includes a supporting structure, and the supporting structure is arranged on the outside of the metal casing.

In the casting bus bar with a metal casing as described above, preferably, the insulating material is epoxy resin.

In the cast bus bar with a metal shell as described above, preferably, the cross section of the inner conductor perpendicular to the axis of the inner conductor is rectangular, and the cross section of the metal shell perpendicular to the axis of the metal shell is square.

In the casting bus bar with a metal shell as described above, preferably, the material of the metal shell and the connecting shell is the same, and the material of the connecting plate and the inner conductor is the same; the material of the inner conductor can be copper, aluminum and new Copper-clad aluminum, and the material of the metal shell can also be copper, aluminum and new copper-clad aluminum, but based on cost considerations, the materials of the metal shell and the connecting shell are preferably aluminum.

Another aspect of the present invention provides a method for manufacturing the metal-cased cast busbar, the method comprising:

Step S10, exposing inner conductors of a certain length at both ends of the standard unit segment;

Step S20, using an internal connection component to connect the exposed inner conductors at the ends of two adjacent standard cell segments, so as to conduct the inner conductors of the two adjacent standard cell segments;

Step S30, the first flange is socketed on the metal casing of one of the two adjacent standard unit segments, the second flange is socketed on the metal casing of the other standard cell segment, and the top surface of the connecting casing is The other faces of each are respectively connected between the first flange and the second flange, thereby forming a casting mold with no cover at the upper end;

Step S40, covering the upper end of the casting mold with a temporary upper cover having the same shape as the top surface of the connecting shell and having a sprue, and then using a pouring process to pour the mixed pouring material on the inner connection component and An intermediate connection insulating layer is formed between the connection shells;

Step S50, remove the temporary upper cover after pouring, connect the upper top surface of the connection shell between the first flange and the second flange to form a closed connection shell, and form the castable after solidification The above-mentioned metal casing casts the busbar.

In the manufacturing method as described above, preferably, the temporary upper cover is also provided with a vacuum port, and the casting process is a vacuum film casting process, including the following steps:

Equipment installation steps:

Cover the casting mold covered with the temporary upper cover with a vacuum film so that the casting mold is completely sealed; then insert the vacuum tube connected to the vacuum pump into the vacuum port arranged on the temporary upper cover, and the vacuum pumping The sealing process is carried out between the mouth and the vacuum tube; then the injection pipe connected to the mixing equipment is inserted into the pouring port on the temporary upper cover, and the sealing process is carried out between the pouring port and the injection pipe;

Vacuum steps:

Open the valve of the vacuum pump to vacuumize the inside of the pouring mold until the specified vacuum pressure value is reached;

Pouring steps:

Pour the mixed pouring material between the inner connection assembly and the connection shell through the sprue until it is full; during the pouring process, the valve of the vacuum pump is always kept open to ensure that the pressure in the casting mold is set. value;

Vacuum release step: After pouring is completed, first turn off the vacuum pump, and then remove the vacuum tube, injection tube and vacuum film, thereby releasing the vacuum state of the casting mold.

In the above manufacturing method, preferably, the casting material is epoxy resin.

The beneficial effects brought by the technical solution provided by the embodiments of the present invention are:

By setting the metal shell, the mechanical performance of the product is improved, and the epoxy resin insulation layer is also protected. At the same time, it is not necessary to make a mold when the epoxy resin is poured. The cast busbar in the metal casing can be like a phase-separated closed busbar, forming a circulating current on the metal casing during operation, which has a good shielding effect on the magnetic field generated by the inner conductor, so that the external magnetic field of the metal casing can be ignored. The standard unit structure of the aluminum square tube cast busbar is more flexible than the traditional cast busbar application layout. According to the current size, the number of standard units per phase can be combined arbitrarily, which greatly shortens the design and production cycle.

Description of drawings

Fig. 1 is a schematic structural view of a standard unit section of a cast metal busbar provided by an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a three-phase standard unit section of a cast metal busbar provided by an embodiment of the present invention;

Fig. 3 is a schematic diagram of the connection structure of two adjacent standard unit sections in a cast metal bus bar provided by an embodiment of the present invention;

Fig. 4 is a schematic diagram of the connection between the connecting plate and the two inner conductors;

Fig. 5 is a schematic flow chart of a method for manufacturing a cast metal busbar provided by an embodiment of the present invention;

Among them, the symbols in the figure illustrate:

1 standard unit segment,

10 inner conductor, 11 metal shell, 12 intermediate insulating layer,

13 supporting structures, 14 connecting metal sheets,

20 inner connecting components, 201 connecting plate, 202 bolts,

21 external connection assembly, 210 first flange, 211 second flange, 212 connecting shell,

22 intermediate connection insulating layers.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the implementation manner of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Referring to Fig. 1 to Fig. 3, the embodiment of the present invention provides a metal casing cast busbar, which includes: a plurality of standard unit sections 1; and a connecting component, which is connected to any two adjacent standard unit sections 1, to Combine multiple standard unit segments 1 and connect them together.

Wherein, as shown in FIG. 1 , any standard unit segment 1 includes: an inner conductor 10 , a metal shell 11 and an intermediate insulating layer 12 . The metal shell 11 is sleeved on the outer side of the inner conductor. Preferably, the axis of the metal shell 11 coincides with the axis of the inner conductor 10 , and the length of the metal shell 11 is equal to the length of the inner conductor 10 . The mixed insulating material is poured between the inner conductor 10 and the metal shell 11 to form the intermediate insulating layer 12. The pouring method can be a vacuum casting process, or a normal pressure casting process, preferably a vacuum film casting process. In this implementation For example, this is not limited, and the insulating material is a material that prevents the conduction between the inner conductor and the metal shell, preferably epoxy resin.

In practice, the shape of the inner conductor and the metal shell can be: the cross section perpendicular to the axis of the inner conductor is rectangular, the cross section perpendicular to the axis of the metal shell is square; the cross section perpendicular to the axis of the inner conductor can also be circular, perpendicular to the The cross section of the metal shell axis is circular, which is not limited in this embodiment. The inner conductor 10 can be an aluminum busbar or a copper busbar. In this example, an aluminum conductor with a rectangular cross-section is used, or it can also be based on GB/T5585.1-2005 "Copper, Aluminum and Their Alloy Busbars for Electrical Engineering Part One: Copper and Copper Alloys" Busbar" and GB/T5585.2-2005 "Electrical Copper, Aluminum and Their Alloy Busbar Part II: Aluminum and Aluminum Alloy Busbar" select conductors with other cross-sectional shapes and sizes. The material of the metal shell is aluminum, copper, copper-clad aluminum and other metal materials. In order to reduce costs, aluminum is preferably used.

The intermediate insulating layer 12 of the cast bus bar in the metal case adopts epoxy resin as the insulating material, and the epoxy resin not only assumes the role of electrical main insulation, but also bears the role of bearing mechanical stress at the same time. It is suitable for all kinds of harsh environments. It is an all-weather product. It can work in the environment of minus 40 degrees for a long time, and can also be buried in the ground; it can work for a long time in the environment with explosion hazard and corrosive liquid; it can still maintain high temperature Good insulation; epoxy resin is halogen-free, flame-retardant and does not release toxic gases; has high mechanical strength and impact resistance. It not only has excellent insulation performance, but also has a high carrying capacity, and is small in size, easy to install, and does not require high requirements for civil engineering foundations. It does not require heating to drive away moisture, nor does it need to be equipped with micro positive pressure devices to ensure the insulation level of the busbar. It has a record of safe operation for more than 30 years without replacement and maintenance, and truly realizes the maintenance-free function. In addition, the inner conductor and the metal shell can be connected as a whole to improve the mechanical strength.

The shell of the cast bus bar with metal shell adopts metal shell 11, which can increase the mechanical strength of the product, protect the epoxy resin layer from erosion and damage, and can sense the circulating current to shield the magnetic field inside the metal shell, and will not cause heating of nearby steel structures, etc. , At the same time, aluminum is used as the metal shell. Since aluminum is a good conductor of heat, it can also increase heat dissipation and improve product performance. The aluminum casing is also used as a metal casing, which can be grounded in practical applications, so that the potential of the metal casing is zero, which can not only protect personal safety, but also avoid phase-to-phase short circuit.

In practice, the length of each standard unit segment 1 is 1-4 m, preferably 3 m, and the length generally refers to the length of the inner conductor 10 . The number of standard unit sections 1 of cast metal busbars can be adjusted adaptively according to the cross-sectional area and current size of the inner conductor 10. Since three-phase power is commonly used in power transmission systems, when the system uses cast metal busbars, each A phase consists of one or more standard cell segments1. The cast bus bar in the prior art is a three-phase cast integrated structure. Products with low voltage levels do not need casings, that is, no magnetic field shielding; products with high voltage levels usually have metal casings, but the metal casings seal the three-phase conductors together. It is equivalent to the traditional closed-box busbar structure, and the present invention has a metal shell for each phase of the cast busbar with a metal shell, and adopts a fully connected connection. Compared with the castable busbar of the prior art, it can basically Negligible effect of magnetic field outside the metal enclosure.

Referring to Fig. 2, there is also a support structure 13 on the outside of the metal shell of the metal shell cast busbar. The support structure 13 can be made of epoxy resin or other insulating materials or metal materials. Each standard unit The section is supported and fixed by two upper and lower support structures 13, and the threaded embedded metal inserts are set on the support structure 13, and the upper and lower support structures 13 are fixed together by bolts and connecting metal sheets 14.

Referring to FIG. 3 , the connection assembly includes: an inner connection assembly 20 , an outer connection assembly 21 and an intermediate connection insulating layer 22 .

The inner connecting component 20 is connected to the inner conductors 10 of two adjacent standard unit segments 1 to communicate the inner conductors 10 of the two adjacent standard unit segments.

Specifically, referring to FIG. 3 and FIG. 4 , the inner connection assembly 20 includes a connection plate 201 and bolts 202 . One end of the connecting plate 201 is connected to the inner conductor of one of the two adjacent standard unit segments, and the other end is connected to the inner conductor of the other standard unit segment, so that the inner conductors of the adjacent two standard unit segments are connected, Bolts 202 fix the two ends of the connecting plate on the inner conductor respectively (for example, there is a through hole in the connecting part of the conductor, and a positioning hole is also opened on the connecting plate. After a certain distance (such as 10mm) between the two inner conductors, pass through the bolt and nut. respectively connected to the connection board). In addition, it is preferable that the bolts are evenly arranged on the connecting plate, so that the connecting plate and the conductor connecting part are in good contact and the contact resistance is reduced.

In other embodiments, it is also possible not to use the internal connection component, but to use the welding method, that is, the inner conductors of two adjacent standard unit sections are connected by welding, but when the two sections of conductors are directly connected by welding, the two conductors The contact surface is very small, and the welding process will also lead to an increase in contact resistance, which will cause serious heating of the contact part, risk of fusion welding, etc., and greatly reduce safety. Therefore, it is more preferable to use the connection method of connecting plate screw connection.

In addition, it is preferable that the connecting plate and the conductor are made of the same material with the same cross-section. Firstly, the material of the connecting plate 201 corresponds to the material of the inner conductor, for example, if the material of the inner conductor is aluminum, then the material of the connecting plate is aluminum; if the material of the inner conductor is copper, then the material of the connecting plate is copper. The shape of the connection plate is plate-shaped and corresponds to the shape of the inner conductor. For example, if the shape of the inner conductor is rectangular, the shape of the connection plate is rectangular; if the shape of the inner conductor is circular, the shape of the connection plate is arc-shaped. plate shape. When installing, it is preferable that the sum of the exposed (extended) lengths of the respective inner conductors of two adjacent standard unit segments is slightly longer than the connection plate, and the total length of the conductor connection parts on both sides is greater than the length of the connection plate, in order to increase the installation area of the connection plate. In principle, the longer the length of the connecting plate, the larger the contact surface with the conductor and the better the contact. That is, the left end of the connection plate is screwed to the exposed inner conductor of one (left) standard unit segment of the two adjacent standard unit segments, and the right end is screwed to the exposed inner conductor of the other (right) standard unit segment. Make sure that the connection plates are connected with maximum area.

The external connection assembly 21 includes a first flange 210, a second flange 211 and a connecting shell 212. The first flange 210 and the second flange 211 are respectively arranged on the metal shells of two adjacent standard unit sections, and are connected Each surface of the shell 212 is respectively fixedly connected with the first flange 210 and the second flange 211 so as to connect the metal shells of two adjacent standard unit sections, and the fixed connection is a bolt connection.

The mixed casting material is poured between the inner connection component 20 and the outer connection component 21 to form the intermediate connection insulating layer 22. The casting method can be a vacuum casting process, or a normal pressure casting process, preferably a vacuum film casting process , which is not limited in this embodiment. The pouring material is a material that prevents the conduction between the inner connection component and the outer connection component, preferably epoxy resin.

Specifically, the connecting shell 212 includes an upper top metal plate, a front side metal plate, a lower side metal plate and a rear side metal plate; The ends are respectively connected with the first flange and the second flange by bolts. The connection housing 212 is preferably made of aluminum. The material of the first flange and the second flange is preferably the same as that of the metal casing 11 , for example both are aluminum or both are copper.

In another embodiment of the present invention, there is provided a method for manufacturing a metal-cased cast busbar. The metal-cased casted busbar is the above-mentioned metal-cased casted busbar. The manufacturing method is shown in FIG. 5 , including:

Step S10, exposing inner conductors of a certain length at both ends of the standard unit segment;

In production, a certain length of exposed inner conductor can be reserved at both ends of the metal shell of the standard unit section, and the two ends of the metal shell of the standard unit section and the intermediate insulating layer can be stripped to expose a certain length of inner conductor. The inner conductor with a certain length shall be subject to the inner conductor suitable for connecting two adjacent standard unit segments.

Step S20, using an internal connection component to connect the exposed inner conductors at the ends of two adjacent standard cell segments, so as to conduct the inner conductors of the two adjacent standard cell segments;

This step specifically includes:

Set connection plates and bolts as inner connection components;

Cover the two ends of the connecting plate on the exposed inner conductors of the two adjacent standard unit sections respectively, and fix the two ends of the connecting plate on the exposed inner conductors respectively with bolts. In practice, the exposed inner conductors can also be Weld to connect inner conductors of adjacent standard cell segments.

Step S30, the first flange is socketed on the metal casing of one of the two adjacent standard unit segments, the second flange is socketed on the metal casing of the other standard cell segment, and the top surface of the connecting casing is The other faces of each are respectively connected between the first flange and the second flange, thereby forming a casting mold with no cover at the upper end;

This step specifically includes:

The connection shell includes an upper top metal plate, a front side metal plate, a lower side metal plate and a rear side metal plate;

The metal plate on the lower side, the metal plate on the front side and the metal plate on the rear side are respectively connected between the first flange connection and the second flange by bolts to form a casting mold with no cover at the upper end (the upper end is an opening).

In step S40, a temporary upper cover having the same shape as the upper surface of the connection shell and having a pouring port and a vacuum port is placed on the upper end of the casting mold, and then the mixed castable is poured on the inner connection by a casting process Between the component and the connection shell to form an intermediate connection insulation layer;

The castable is preferably epoxy resin, which includes bisphenol A epoxy resin, modified epoxy resin, novolac epoxy resin, vinyl resin, phenolic resin, brominated epoxy resin and liquid cycloaliphatic One or more of epoxy resins, etc., with or without fillers; the resins used can also be polyurethane resins, polyimide resins (such as bismaleimide (BMI) resins), etc. Resin with casting process.

The casting process is preferably a vacuum film casting process, and the specific operations are as follows:

1) Equipment installation:

Cover the casting mold covered with the temporary cover with a vacuum film (such as a commercially available vacuum film with a thickness of 30 μm to 70 μm and a certain degree of toughness), and use soft materials such as cloth to cover the four pieces of metal connected to the shell. The sharp corners of the board are wrapped to ensure that the vacuum film is not damaged, so that the casting mold forms a sealed space; then insert the vacuum tube connected to the vacuum pump into the vacuum port provided on the temporary upper cover, and The commercially available sealing tape is used to seal the vacuum tube; the injection pipe connected to the mixing equipment is also inserted into the sprue on the temporary upper cover, and the sprue on the film is connected with the injection The tubes are sealed with commercially available sealing strips;

2) Vacuuming:

Close the injection port valve of the mixing equipment, open the valve of the vacuum pump, and vacuum the inside of the cavity of the mold for 10-50s, preferably 30s, then close the valve of the vacuum pump to check whether there is any leakage caused by improper sealing. If there is no air leakage, open the valve of the vacuum pump and vacuumize the space wrapped by the vacuum film for 1 to 5 minutes, preferably 3 minutes, until the specified vacuum pressure value is reached, for example, the vacuum value is 300~ 1000Pa, preferably 650Pa and stable (the vacuuming time is determined by the mold volume and the required pressure value; in addition, the vacuum pressure value is also determined according to the process requirements of different resin systems, for example, it can also be 700Pa, general electrical resin The process requirement of the system is within 2000Pa);

3) Pouring:

After the material mixing in the mixing equipment is completed, the pouring material can be obtained, and then the pouring can be carried out; open the valve of the injection port of the mixing equipment, and let the pouring material flow into the space between the inner connection component and the connecting shell along the pouring opening until it is full. Close the injection port valve of the mixing equipment to complete pouring;

During the pouring process, the valve of the vacuum pump is always kept open to ensure that the pressure in the space covered by the vacuum film is at the set value; if the pressure value changes greatly during the pouring period, the pressure value can be maintained at the set value by adjusting the valve of the vacuum pump. Fixed value (the set value is 300-2000Pa, such as 500Pa, 700Pa, 900Pa, 1100Pa, 1300Pa, 1500Pa, 1700Pa, preferably below 1000Pa, more preferably below 650Pa);

4) After the pouring is completed, first turn off the vacuum pump, and then remove all the pipelines and vacuum films to release the vacuum state of the casting mold;

Step S50, removing the temporary upper cover after releasing the vacuum state, screwing the metal plate on the upper top surface of the connecting shell between the first flange and the second flange to form a closed connecting shell, to be poured After the material is solidified, the metal casing casting busbar of the present invention is formed.

During on-site installation, it is only necessary to connect multiple standard unit sections of corresponding phases to form a metal casing cast busbar. First, put the first flange and the second flange on the metal casings of the two adjacent standard unit sections respectively. flange. Then, connect the exposed inner conductors into one body through the connecting plate and fix them with bolts. The connection section housing consists of four aluminum metal plates. Screw the bottom surface and two side surfaces of the shell of the connecting section with the first flange and the second flange respectively to form a simple mold without an upper cover. The mixed castable is poured into the shell of the connecting section by vacuum casting process, normal pressure pouring process or vacuum film casting process, and then the upper cover of the shell of the connecting section is screwed together. After curing is complete, there is no need to demould.

In summary, the beneficial effects brought by the present invention are as follows:

As a new type of epoxy resin cast busbar, the metal shell cast busbar has a series of advantages such as small size, large carrying capacity, flame retardancy, chemical corrosion resistance, and maintenance-free, and the metal shell is used as the product shell, which improves the The mechanical properties of the product also protect the epoxy resin layer, and there is no need to make molds. When the bus bar is working, it can form a circulating current on the metal shell, which can shield the magnetic field generated by the inner conductor well, so that the external magnetic field of the metal shell can be ignored. The cast metal busbar is composed of one or more standard unit segments, which makes the production and assembly of the cast metal busbar more convenient and cost-saving. Moreover, the application layout is more flexible, and the number of standard unit segment structures of each phase can be combined arbitrarily according to the magnitude of the current, which greatly shortens the design and production cycle. And the structure of the standard unit section can be a right-angle unit or a special unit such as a T-joint unit, which can be adjusted according to actual production needs to meet the needs of different customers.

The external connecting component in the connecting component is not only a mold but also bears mechanical stress. It does not need to be demolded when pouring insulating materials, and it can be grounded during use, making the operation safer and more reliable.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (11)

1. A casting busbar with a metal casing, characterized in that the casting busbar with a metal casing comprises: multiple standard cell segments; and A connection component, connected to any two adjacent standard unit segments; Wherein, any one of the standard unit segments includes: inner conductor; a metal shell sleeved on the circumferential outer side of the inner conductor; and An intermediate insulating layer formed by filling an insulating material between the inner conductor and the metal shell by casting; Wherein, the connection components include: An inner connecting component, connected to the inner conductors of two adjacent standard cell segments so that the inner conductors of the two adjacent standard cell segments communicate; An external connection assembly provided with a first flange, a second flange and a connecting shell, the first flange and the second flange are respectively socketed on the metal shells of two adjacent standard unit segments, Each surface of the connecting shell is respectively fixedly connected between the first flange and the second flange so as to connect the metal shells of two adjacent standard unit segments; and The intermediate connecting insulating layer is formed by filling the insulating material between the inner connecting component and the outer connecting component in a pouring form. 2. The metal casing cast busbar according to claim 1, characterized in that, The inner connecting assembly includes connecting plates and bolts; Both ends of the connection plate are respectively connected to the inner conductors of two adjacent standard unit segments, and the bolts respectively fix the two ends of the connection plate to the inner conductors. 3. The metal casing cast busbar according to claim 2, characterized in that, The connection shell includes an upper top metal plate, a front side metal plate, a lower side metal plate and a rear side metal plate; Two ends of the upper top metal plate, the front side metal plate, the lower side metal plate and the rear side metal plate are respectively connected to the first flange and the second flange by bolts. 4. The metal casing cast busbar according to claim 2, characterized in that, The standard unit segment also includes a supporting structure, and the supporting structure is arranged on the outside of the metal casing. 5. The metal casing cast busbar according to claim 1, characterized in that, The insulating material is epoxy resin. 6. The metal casing cast busbar according to claim 1, characterized in that, The section of the inner conductor perpendicular to the axis of the inner conductor is rectangular, The cross section of the metal shell perpendicular to the axis of the metal shell is square. 7. The metal casing cast busbar according to claim 2, characterized in that, The metal shell and the connection shell are made of the same material, The connecting plate and the inner conductor are made of the same material. 8. The cast metal bus bar according to claim 7, characterized in that: Both the metal shell and the connection shell are made of aluminum. 9. A method for manufacturing the cast metal busbar according to any one of claims 1-8, characterized in that the method comprises: Step S10, exposing inner conductors of a certain length at both ends of the standard unit segment; Step S20, using an internal connection component to connect the exposed inner conductors at the ends of two adjacent standard cell segments, so as to conduct the inner conductors of the two adjacent standard cell segments; Step S30, the first flange is socketed on the metal casing of one of the two adjacent standard unit segments, the second flange is socketed on the metal casing of the other standard cell segment, and the top surface of the connecting casing is The other faces of each are respectively connected between the first flange and the second flange, thereby forming a casting mold with no cover at the upper end; Step S40, covering the upper end of the casting mold with a temporary upper cover having the same shape as the top surface of the connecting shell and having a sprue, and then using a pouring process to pour the mixed pouring material on the inner connection component and between the connecting shells to form an intermediate connecting insulating layer; Step S50, remove the temporary upper cover after pouring, connect the upper top surface of the connection shell between the first flange and the second flange to form a closed connection shell, and form the castable after solidification The above-mentioned metal casing casts the busbar. 10. The manufacturing method of the metal casing casting bus bar according to claim 9, characterized in that, The temporary upper cover is also provided with a vacuum port, The pouring process is a vacuum film casting process, comprising the steps of: Equipment installation steps: Cover the casting mold covered with the temporary upper cover with a vacuum film so that the casting mold is completely sealed; then insert the vacuum tube connected to the vacuum pump into the vacuum port arranged on the temporary upper cover, and the vacuum pumping The sealing process is carried out between the mouth and the vacuum tube; then the injection pipe connected with the mixing equipment is inserted into the pouring mouth arranged on the temporary upper cover, and the sealing treatment is carried out between the pouring mouth and the injection pipe; Vacuum steps: Open the valve of the vacuum pump to vacuumize the inside of the pouring mold until the specified vacuum pressure is reached; Pouring steps: Pour the mixed pouring material between the inner connection assembly and the connection shell through the sprue until it is full; during the pouring process, the valve of the vacuum pump is always kept open to ensure that the pressure in the casting mold is set. value; Vacuum release step: After pouring is completed, first turn off the vacuum pump, and then remove the vacuum tube, injection tube and vacuum film, so as to release the vacuum state of the casting mold. 11. The manufacturing method of the metal casing casting bus bar according to claim 9, characterized in that, The casting material is epoxy resin.