A medium voltage cable for photovoltaic power generation

Abstract

The application discloses a kind of photovoltaic power generation medium voltage cable, it is related to cable technical field, support reinforcing assembly is arranged in outer insulating layer, middle support pipe is arranged in the middle of outer insulating layer inside, inside wire is uniformly bonded in outer insulating layer, gas hole is uniformly opened in the position between adjacent inside wire at the outside of middle support pipe, porous heat-conducting silica gel strip is arranged at the gas hole of middle support pipe, filling layer is filled between outer insulating layer and inside wire, gas long hole is opened in the place close to inside wire of filling layer, armour net layer is wrapped in the outside of filling layer, outer auxiliary protection assembly is installed in the outside of outer insulating layer, the chain structure of reinforcing thin pipe and reinforcing thick pipe combination is supported in the application, inflatable hose deforms, improve cable bending resistance, pressurized carbon dioxide in inflatable hose can be discharged, cooperate with flame-retardant tube and filling layer, protect cable when overheating combustion, reduce the damage of cable.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to a medium-voltage cable for photovoltaic power generation. Background Technology

[0002] A cable is a device for transmitting electrical energy or signals, usually composed of several or groups of wires. Photovoltaic cables are a type of cable, specifically designed for use in solar power generation systems. They need to be used for extended periods in harsh environments such as high temperatures and ultraviolet radiation, which conventional PVC or rubber cables cannot meet. The characteristics of photovoltaic cables are determined by their special insulation and sheathing materials, which are cross-linked PE. Irradiation alters their molecular structure, thereby improving their performance.

[0003] However, photovoltaic cables currently on the market are often subjected to compression and bending during installation, such as overhead or underground installations in the field, and come into contact with sharp stone edges. If the cable sheath is not strong enough, the cable insulation layer will be severely damaged, thus affecting the service life of the entire cable. However, the existing cable structure is difficult to cope with various complex and harsh environments. Summary of the Invention

[0004] This invention provides a medium-voltage cable for photovoltaic power generation, which can effectively solve the problem mentioned in the background art that if the cable sheath strength is insufficient, the cable insulation layer will be severely damaged, thereby affecting the service life of the entire cable. However, the structure of existing cables is difficult to cope with various complex and harsh environments.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a medium-voltage cable for photovoltaic power generation, comprising an outer insulation layer, wherein a support and reinforcement component is disposed inside the outer insulation layer, and the support and reinforcement component comprises a central support tube; A central support tube is provided in the middle of the inner part of the outer insulation layer; The inner side of the outer insulation layer is uniformly bonded with an inner conductor. The outer side of the middle support tube is uniformly provided with vent holes between adjacent inner conductors. The middle support tube is provided with a porous thermally conductive silicone strip at the vent holes. A filling layer is filled between the outer insulation layer and the inner conductor. The filling layer is provided with a long vent hole near the inner conductor. An armored mesh layer is wrapped around the outside of the filling layer. The filling layer has a support groove between adjacent inner conductors. Reinforcing thin tubes are uniformly installed inside the support groove. Reinforcing thick tubes are movably sleeved at both ends of the reinforcing thin tubes. A movable end ring is welded to the end of the reinforcing thin tube inside the reinforcing thick tube. A sealing groove is opened on one side of the movable end ring. A hot melt block is bonded inside the sealing groove. Two opposite hot melt blocks are respectively bonded to both ends of the inflation hose.

[0006] According to the above technical solution, an inner reinforcing steel rope is provided in the middle of the middle support tube, and a connecting outer tube is sleeved on the outside of the inner reinforcing steel rope. The outer side of the connecting outer tube is bonded to the inner side of the middle support tube. A flame-retardant tube is uniformly filled at the end of the middle support tube, and a dry block is filled inside the flame-retardant tube.

[0007] According to the above technical solution, pressure relief holes are provided at both ends of the inflatable hose, a transition tube is bonded between two adjacent reinforced thick tubes, a limit heat fusion ring is embedded in the end plate of the reinforced thick tube, and pressurized carbon dioxide gas is filled inside the inflatable hose.

[0008] According to the above technical solution, the longitudinal section of the hot melt block is T-shaped, and one end of the hot melt block is embedded in the pressure relief hole.

[0009] According to the above technical solution, the outer diameter of the reinforced thin tube and the inner diameter of the movable end ring are the same, the outer side of the movable end ring is attached to the inner side of the reinforced thick tube, and the outer edge of the movable end ring is rounded.

[0010] According to the above technical solution, a pressure relief groove is formed on the outer side of the outer insulation layer, and a wear-resistant ring is sleeved inside the pressure relief groove. The outer side of the wear-resistant ring is aligned with the outer side of the outer insulation layer.

[0011] According to the above technical solution, an external auxiliary protection component is installed on the outside of the outer insulation layer, and the external auxiliary protection component includes an inner spiral collar; An inner spiral collar is sleeved on the outer side of the outer insulation layer. A thermally conductive spiral gasket is bonded inside the inner spiral collar. An outer spiral collar is sleeved on the outer side of the thermally conductive spiral gasket. A reflective thermally conductive layer is symmetrically sleeved on the outer side of the outer spiral collar. A semi-circular hoop is uniformly bonded on the outer side of the reflective thermally conductive layer. Heat dissipation fins are uniformly distributed on the outer side of the semi-circular hoop. A connecting clamp plate is welded to one end of the semi-circular hoop, and a connecting clamp hole plate is welded to the other end of the semi-circular hoop.

[0012] According to the above technical solution, a C-shaped rubber clip is sleeved on the outer side of the outer insulation layer at both ends of the inner spiral collar. A C-shaped hole is opened in the middle of the C-shaped rubber clip. A supporting rubber strip is evenly adhered inside the C-shaped hole. A central airbag is embedded inside the C-shaped hole at the position between the supporting rubber strips. End airbags are connected to both ends of the central airbag. A C-shaped spring steel sheet is sleeved on the outer side of the C-shaped rubber clip.

[0013] According to the above technical solution, the inner side of the C-shaped rubber card is provided with an adhesive groove, the inside of the adhesive groove is filled with adhesive, and the inner side of the C-shaped rubber card is attached to the outer side of the outer insulation layer.

[0014] According to the above technical solution, the two opposite semi-ring hoops are spliced ​​together to form a ring, the connecting card plate and the connecting card hole plate are engaged with each other, and the end face of the reflective heat-conducting layer is semi-ring.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Equipped with a support and reinforcement component, the cable is supported by a chain structure composed of a thin and thick reinforcing tube when it bends. The movable end ring slides inside the thick reinforcing tube, and the air hose deforms to provide cushioning. The chain structure reduces the bending amplitude and provides support to prevent the inner conductor from being damaged due to excessive bending amplitude, thereby improving the cable's bending resistance. The bending resistance is determined by the air pressure inside the air hose. The higher the air pressure inside the air hose, the stronger the bending resistance, thus improving the overall strength of the cable. During normal cable operation, if the internal temperature of the cable rises rapidly, the fusible block will soften and fail, and the pressurized carbon dioxide in the inflation hose will be released. The inside of the cable at that location will be filled with pressurized carbon dioxide, reducing the air ratio. Together with the flame-retardant tube and filling layer, this hinders combustion. If the temperature continues to rise, the carbon dioxide will expand due to heat, pushing up the pressure relief groove of the cable at the heated location and releasing the carbon dioxide from the groove. This prevents the carbon dioxide from affecting other locations. The released carbon dioxide will also temporarily prevent air from entering the cable, preventing the cable from contacting air and burning. This protects the cable and reduces damage during overheating and combustion.

[0016] 2. An external auxiliary protection component is provided. The reflective heat-conducting layer reflects sunlight, reducing the damage of ultraviolet rays to the outer insulation layer. When subjected to external pressure, the inner spiral collar, the heat-conducting spiral gasket, the outer spiral collar, and the C-shaped spring steel sheet are all compressed. The spiral structure, together with the heat-conducting spiral gasket made of heat-conducting silicone material, reduces the impact force and reduces the damage of the cable under pressure and external friction, thus better protecting the cable. When the C-shaped rubber clip is compressed, it deforms, and the gas in the middle air bladder flows to the end air bladders at both ends. The end air bladders contact the compression surface for support, preventing the C-shaped rubber clip that fixes the outer spiral collar from being damaged and falling off due to excessive pressure. In addition, the heat dissipation fins can also dissipate the heat transferred from the inside of the cable to the outer insulation layer, preventing the cable from overheating locally. In summary, the support and reinforcement components utilize a chain-like structure composed of reinforced thin tubes and reinforced thick tubes to improve its bending resistance. In addition, the inner and outer spiral collars on the outside of the outer insulation layer can also improve the cable's bending resistance and compressive strength. The two components work together to further enhance the cable's bending resistance and extend its service life in frequently bending locations. The porous thermally conductive silicone strip structure within the support and reinforcement components makes the heat distribution inside the cable more uniform. This allows heat to be transferred sequentially through the porous thermally conductive silicone strip, the filling layer, and the armor mesh layer to the outer insulation layer, and then discharged by the thermally conductive spiral pad, the reflective thermally conductive layer, and the heat dissipation fins. This better dissipates heat, prevents heat accumulation, improves cable safety, and provides more diverse protective structures for better cable protection. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0018] In the attached diagram: Figure 1 This is a three-dimensional structural schematic diagram of the present invention; Figure 2 This is a schematic diagram of the structure of the support and reinforcement component of the present invention; Figure 3 This is a schematic diagram of the installation structure of the internal conductor of the present invention; Figure 4 This is the present invention. Figure 3 A schematic diagram of the structure of region A; Figure 5 This is a schematic diagram of the installation structure of the reinforced thin tube of the present invention; Figure 6 This is a schematic diagram of the external auxiliary protection component of the present invention; Figure 7 This is a schematic diagram of the installation structure of the C-type rubber clip of the present invention; Labels in the diagram: 1. Outer insulation layer; 2. Support and reinforcement components; 201. Middle support tube; 202. Inner reinforcing steel rope; 203. Connecting outer tube; 204. Flame-retardant tube; 205. Drying block; 206. Inner conductor; 207. Ventilation hole; 208. Porous thermally conductive silicone strip; 209. Filling layer; 210. Ventilation elongated hole; 211. Armored mesh layer; 212. Support groove; 213. Reinforced thin tube; 214. Reinforced thick tube; 215. Movable end ring; 216. Sealing groove; 217. Hot melt block; 218. Inflatable hose; 219. Pressure relief hole; 220. Transition tube; 221. Limiting hot melt ring; 222. Pressure relief groove; 223. Wear-resistant ring; 3. External auxiliary protective components; 301. Inner spiral collar; 302. Thermally conductive spiral gasket; 303. Outer spiral collar; 304. Reflective thermally conductive layer; 305. Semi-ring clamp; 306. Heat dissipation fins; 307. Connecting clip plate; 308. Connecting clip hole plate; 309. C-type rubber clip; 310. C-type hole; 311. Supporting rubber strip; 312. Central airbag; 313. End airbag; 314. C-type spring steel sheet; 315. Glue groove. Detailed Implementation

[0019] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0020] Example: Figure 1-7As shown, the present invention provides a medium-voltage cable technical solution for photovoltaic power generation, including an outer insulation layer 1, and a support and reinforcement component 2 disposed inside the outer insulation layer 1. The support and reinforcement component 2 includes a middle support tube 201, an inner reinforcing steel rope 202, a connecting outer tube 203, a flame-retardant tube 204, a drying block 205, an inner conductor 206, a vent hole 207, a porous thermally conductive silicone strip 208, a filling layer 209, a vent elongated hole 210, an armored mesh layer 211, a support groove 212, a reinforcing thin tube 213, a reinforcing thick tube 214, a movable end ring 215, a sealing groove 216, a hot melt block 217, an air-filled hose 218, a pressure relief hole 219, a transition tube 220, a limiting hot melt ring 221, a pressure relief crack groove 222, and a wear-resistant ring 223. The outer insulation layer 1 has a central support tube 201 in the middle, an inner reinforcing steel rope 202 in the middle, a connecting outer tube 203 on the outside of the inner reinforcing steel rope 202, and the inner side of the central support tube 201 is bonded to the outside of the connecting outer tube 203. The end of the central support tube 201 is evenly filled with a flame-retardant tube 204, and the inside of the flame-retardant tube 204 is filled with a drying block 205 to improve the tensile strength of the cable and keep the inside dry. An inner conductor 206 is uniformly bonded to the inner side of the outer insulation layer 1. Ventilation holes 207 are uniformly opened on the outer side of the middle support tube 201 between adjacent inner conductors 206. A porous thermally conductive silicone strip 208 is provided on the middle support tube 201 at the ventilation hole 207. A filling layer 209 is filled between the outer insulation layer 1 and the inner conductor 206. Ventilation holes 210 are opened on the filling layer 209 near the inner conductor 206. An armored mesh layer 211 is wrapped around the outer side of the filling layer 209. A support groove 212 is provided in the filler layer 209 between adjacent inner conductors 206. Reinforcing thin tubes 213 are uniformly installed inside the support groove 212. Reinforcing thick tubes 214 are movably sleeved at both ends of the reinforcing thin tubes 213. A movable end ring 215 is welded to the end of the reinforcing thin tube 213 inside the reinforcing thick tube 214. The outer diameter of the reinforcing thin tube 213 is the same as the inner diameter of the movable end ring 215. The outer side of the movable end ring 215 is fitted against the inner side of the reinforcing thick tube 214. The outer edge of the movable end ring 215 is rounded to facilitate sliding within the reinforcing thick tube 214. A sealing groove 216 is provided on one side of the movable end ring 215. A hot melt block 217 is bonded inside the sealing groove 216. Two hot melt blocks 217 are respectively bonded to both ends of the air hose 218. Both ends of the air hose 218 are provided with pressure relief holes 219. The longitudinal section of the hot melt block 217 is T-shaped. The middle of one end of the hot melt block 217 is embedded in the pressure relief hole 219 to facilitate the hot melt block 217 to seal the pressure relief hole 219. A transition pipe 220 is bonded between two adjacent reinforced thick pipes 214. The end plate of the reinforced thick pipe 214 is inlaid with a limiting hot melt ring 221. The air hose 218 is filled with pressurized carbon dioxide gas. A pressure relief groove 222 is provided on the outer side of the outer insulation layer 1. A wear-resistant ring 223 is sleeved inside the pressure relief groove 222. The outer side of the wear-resistant ring 223 is aligned with the outer side of the outer insulation layer 1.

[0021] An external auxiliary protection component 3 is installed on the outside of the outer insulation layer 1. The external auxiliary protection component 3 includes an inner spiral collar 301, a heat-conducting spiral gasket 302, an outer spiral collar 303, a reflective heat-conducting layer 304, a semi-ring 305, a heat dissipation fin 306, a connecting clip plate 307, a connecting clip hole plate 308, a C-type rubber clip 309, a C-type hole 310, a supporting rubber strip 311, a central airbag 312, an end airbag 313, a C-type spring steel sheet 314, and an adhesive groove 315. An inner spiral collar 301 is sleeved on the outer side of the outer insulation layer 1. A heat-conducting spiral gasket 302 is bonded inside the inner spiral collar 301. An outer spiral collar 303 is sleeved on the outer side of the heat-conducting spiral gasket 302. A reflective heat-conducting layer 304 is symmetrically sleeved on the outer side of the outer spiral collar 303. A semi-circular hoop 305 is uniformly bonded on the outer side of the reflective heat-conducting layer 304. Heat dissipation fins 306 are evenly distributed on the outer side of the semi-circular hoop 305. A connecting clip plate 307 is welded to one end of the semi-circular hoop 305, and a connecting clip hole plate 308 is welded to the other end of the semi-circular hoop 305. The two opposite semi-circular hoops 305 are spliced ​​into a ring. The connecting clip plate 307 and the connecting clip hole plate 308 are interlocked. The end face of the reflective heat-conducting layer 304 is semi-circular, which facilitates fixing the semi-circular hoop 305 to the outer side of the reflective heat-conducting layer 304.

[0022] A C-shaped rubber clip 309 is sleeved on the outer side of the outer insulation layer 1 at both ends of the inner spiral collar 301. The inner side of the C-shaped rubber clip 309 has an adhesive groove 315, which is filled with adhesive. The inner side of the C-shaped rubber clip 309 is attached to the outer side of the outer insulation layer 1 to facilitate the bonding and fixing of the C-shaped rubber clip 309, so that the two ends of the C-shaped rubber clip 309 are close to each other. A C-shaped hole 310 is opened in the middle of the C-shaped rubber clip 309. A support strip 311 is evenly bonded inside the C-shaped hole 310. A central airbag 312 is embedded in the C-shaped hole 310 between the support strips 311. The two ends of the central airbag 312 are connected to end airbags 313. A C-shaped spring steel sheet 314 is sleeved on the outer side of the C-shaped rubber clip 309.

[0023] The working principle and usage process of this invention: The outer side of the inner reinforcing steel rope 202 is wrapped with the outer tube 203 by an extruder. The flame-retardant tube 204 is filled with spherical granular dry blocks 205. The flame-retardant tube 204 is a hollow rope structure woven from halogen-free flame-retardant material. The flame-retardant tube 204 and the inner support tube 201 are wrapped with the middle support tube 201 by an extruder. The outer tube 203 is then bonded to the inner side of the middle support tube 201. Then, the inner wire 206 is bonded to the outer side of the middle support tube 201. A vent hole 207 is opened in the middle support tube 201 at the gap between the inner wires 206. A porous thermally conductive silicone strip 208 is bonded to the middle support tube 201 near the vent hole 207. The reinforced thin tube 213 and the reinforced thick tube 214 are combined into a long chain, and the structure is as follows: Figure 3 and Figure 5 As shown, the long chain-like material is temporarily bonded to one side of the porous thermally conductive silicone strip 208, and the outer side of the whole is wrapped with the filling layer 209 by an extruder, while retaining the ventilating long holes 210. Then, the armor mesh layer 211 is wrapped around the outside of the filling layer 209. Finally, the outer insulation layer 1 is wrapped around the outside of the armor mesh layer 211 by an extruder. As needed, pressure relief grooves 222 are opened on the outside of the outer insulation layer 1. The position and density of the pressure relief grooves 222 are opened as needed, and wear-resistant rings 223 are snapped into the pressure relief grooves 222 to complete the cable production. The external auxiliary protection component 3 is selected according to the environment when laying the cable. When laying cables outdoors, in locations susceptible to external influences such as sunlight, pressure, and bending, a spiral structure consisting of an inner spiral collar 301, a heat-conducting spiral gasket 302, and an outer spiral collar 303 is fitted onto this section. Adhesive is then applied to the adhesive groove 315. A C-shaped rubber clip 309, equipped with a central airbag 312, is then clipped onto the outer side of the outer insulation layer 1 near the end of the outer spiral collar 303. The C-shaped rubber clip 309 is then bent to... Under the pressure of the C-shaped spring steel sheet 314, the two ends of the card 309 approach each other and bend into a ring. After the glue in the glue tank 315 dries, the reflective heat-conducting layer 304 with the half-ring 305 attached is taken out and symmetrically wrapped around the outer spiral collar 303. The connecting card block plate 307 and the connecting card hole plate 308 are snapped together to protect the cable section. If the cable is indoors or has been fixed and is in a part with less loss, the external auxiliary protection component 3 is not installed to reduce the laying cost. During cable use, the outdoor portion equipped with external auxiliary protection components 3 reflects sunlight through the reflective heat-conducting layer 304, reducing ultraviolet damage to the outer insulation layer 1. When subjected to external pressure, the inner spiral collar 301, the heat-conducting spiral gasket 302, the outer spiral collar 303, and the C-shaped spring steel sheet 314 are all compressed. The spiral structure, combined with the heat-conducting spiral gasket 302 made of heat-conducting silicone material, reduces the impact force and reduces the cable's damage from pressure and external friction, thus better protecting the cable. When the C-shaped rubber clip 309 is compressed, it deforms, and the gas in the central air bladder 312 flows to the end air bladders 313 at both ends. The end air bladders 313 contact the compression surface for support, preventing the C-shaped rubber clip 309 that fixes the outer spiral collar 303 from being damaged or falling off due to excessive pressure. The heat dissipation fins 306 can also dissipate the heat transferred from inside the cable to the outer insulation layer 1, preventing local overheating of the cable. During cable use, water vapor inside the cable is absorbed by the drying block 205 inside the flame-retardant tube 204, keeping the inside of the cable dry. When the cable is bent, the chain structure composed of the reinforcing thin tube 213 and the reinforcing thick tube 214 provides support. Both the reinforcing thin tube 213 and the reinforcing thick tube 214 are made of fiberglass. When bending, the movable end ring 215 slides inside the reinforcing thick tube 214, squeezing the air hose 218 filled with pressurized carbon dioxide. The air hose 218 deforms, providing cushioning. The chain structure composed of the reinforcing thin tube 213 and the reinforcing thick tube 214 reduces the bending amplitude and provides support, preventing the inner conductor 206 from being damaged due to excessive bending amplitude, thus improving the cable's bending resistance. The bending resistance is determined by the air pressure inside the air hose 218. The higher the air pressure inside the air hose 218, the stronger the bending resistance, thus improving the overall strength of the cable. During normal operation of the cable, if a fire breaks out inside the cable due to local short circuit, overheating, or other reasons, and the internal temperature of the cable rises rapidly, exceeding the maximum withstand temperature of the polypropylene hot melt block 217, the hot melt block 217 and the limiting hot melt ring 221 of the same material will soften and fail. The pressurized carbon dioxide in the air-filled hose 218 will be discharged, and the inside of the cable at this location will be filled with pressurized carbon dioxide, reducing the air ratio. Together with the flame-retardant tube 204 and the filling layer 209, it will hinder the combustion process. If the temperature continues to rise, the carbon dioxide will expand due to heat, pushing up the pressure relief groove 222 of the cable at the heated location and discharging from the pressure relief groove 222, thereby avoiding the influence of other locations. The discharged carbon dioxide will also temporarily prevent air from entering the cable, preventing the cable from contacting air and burning. This protects the cable and reduces cable damage during overheating and combustion.

[0024] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A medium-voltage cable for photovoltaic power generation, comprising an outer insulation layer (1), characterized in that: The outer insulation layer (1) is provided with a support and reinforcement component (2), which includes a middle support tube (201). A central support tube (201) is provided in the middle of the inner part of the outer insulation layer (1). The inner side of the outer insulation layer (1) is uniformly bonded with an inner conductor (206). The outer side of the middle support tube (201) is uniformly provided with vent holes (207) between adjacent inner conductors (206). The middle support tube (201) is provided with a porous thermally conductive silicone strip (208). The space between the outer insulation layer (1) and the inner conductor (206) is filled with a filling layer (209). The filling layer (209) is provided with a long vent hole (210) near the inner conductor (206). The outer side of the filling layer (209) is wrapped with an armored mesh layer (211). The reinforced thin tube (213) and the reinforced thick tube (214) are combined into a long chain. The long chain is temporarily bonded to one side of the porous thermal conductive silicone strip (208), and the outer side of the whole is wrapped with a filling layer (209) by an extruder, while retaining the breathable long pores (210). The filling layer (209) has a support groove (212) between adjacent inner conductors (206). A reinforcing thin tube (213) is uniformly installed inside the support groove (212). Both ends of the reinforcing thin tube (213) are movably sleeved with a reinforcing thick tube (214). A movable end ring (215) is welded inside the reinforcing thick tube (214) at the end of the reinforcing thin tube (213). A sealing groove (216) is opened on one side of the movable end ring (215). A hot melt block (217) is bonded inside the sealing groove (216). Two opposite hot melt blocks (217) are respectively bonded to both ends of the air-filled hose (218).

2. The medium-voltage cable for photovoltaic power generation according to claim 1, characterized in that, The middle support tube (201) is provided with an inner reinforcing steel rope (202) in the middle. The outer side of the inner reinforcing steel rope (202) is sleeved with a connecting outer tube (203). The outer side of the connecting outer tube (203) is bonded to the inner side of the middle support tube (201). The end of the middle support tube (201) is uniformly filled with a flame-retardant tube (204). The inside of the flame-retardant tube (204) is filled with a dry block (205).

3. A medium-voltage cable for photovoltaic power generation according to claim 1, characterized in that, The inflatable hose (218) has pressure relief holes (219) at both ends. A transition tube (220) is bonded between two adjacent reinforced thick tubes (214). A limit hot melt ring (221) is embedded in the end plate of the reinforced thick tube (214). The inflatable hose (218) is filled with pressurized carbon dioxide gas.

4. A medium-voltage cable for photovoltaic power generation according to claim 3, characterized in that, The hot melt block (217) has a T-shaped longitudinal section, and one end of the hot melt block (217) is embedded in the pressure relief hole (219).

5. A medium-voltage cable for photovoltaic power generation according to claim 1, characterized in that, The outer diameter of the reinforced thin tube (213) is the same as the inner diameter of the movable end ring (215). The outer side of the movable end ring (215) is attached to the inner side of the reinforced thick tube (214), and the outer edge of the movable end ring (215) is rounded.

6. A medium-voltage cable for photovoltaic power generation according to claim 1, characterized in that, The outer insulating layer (1) has a pressure relief groove (222) on its outer side, and a wear-resistant ring (223) is sleeved inside the pressure relief groove (222). The outer side of the wear-resistant ring (223) is aligned with the outer side of the outer insulating layer (1).

7. A medium-voltage cable for photovoltaic power generation according to claim 6, characterized in that, An external auxiliary protection component (3) is installed on the outside of the outer insulation layer (1), and the external auxiliary protection component (3) includes an inner spiral collar (301). The outer insulating layer (1) is fitted with an inner spiral collar (301), and a heat-conducting spiral gasket (302) is bonded inside the inner spiral collar (301). An outer spiral collar (303) is fitted outside the heat-conducting spiral gasket (302). A reflective heat-conducting layer (304) is symmetrically fitted outside the outer spiral collar (303). A semi-circular hoop (305) is uniformly bonded outside the reflective heat-conducting layer (304). Heat dissipation fins (306) are uniformly distributed outside the semi-circular hoop (305). A connecting clip plate (307) is welded to one end of the semi-circular hoop (305), and a connecting clip hole plate (308) is welded to the other end of the semi-circular hoop (305).

8. A medium-voltage cable for photovoltaic power generation according to claim 7, characterized in that, The outer insulating layer (1) is fitted with C-shaped rubber clips (309) at both ends of the inner spiral collar (301). A C-shaped hole (310) is opened in the middle of the C-shaped rubber clip (309). A support strip (311) is evenly bonded inside the C-shaped hole (310). A central airbag (312) is embedded in the C-shaped hole (310) between the support strips (311). The two ends of the central airbag (312) are connected to end airbags (313). A C-shaped spring steel sheet (314) is fitted on the outside of the C-shaped rubber clip (309).

9. A medium-voltage cable for photovoltaic power generation according to claim 8, characterized in that, The C-type rubber card (309) has an adhesive groove (315) on its inner side, and the adhesive groove (315) is filled with adhesive. The inner side of the C-type rubber card (309) is attached to the outer side of the outer insulation layer (1).

10. A medium-voltage cable for photovoltaic power generation according to claim 7, characterized in that, The two opposite semi-ring hoops (305) are spliced ​​together to form a ring, the connecting block plate (307) and the connecting hole plate (308) are engaged with each other, and the end face of the reflective heat-conducting layer (304) is semi-ring.

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