Medium-voltage rubber jacketed flexible cable with twisted sparsely-wound shielding structure

Abstract

The utility model relates to a medium-voltage rubber jacketed flexible cable with a twisted sparsely-wound shielding structure, and belongs to the technical field of power cables. According to the technical scheme, the cable comprises a metal shielding layer twisted outside a wire core, the metal shielding layer is formed by twisting a plurality of bunch-stranded units, and a gap is reserved between every two adjacent bunch-stranded units; the bunch stranding unit is formed by stranding a plurality of bunch wire units, each bunch wire unit is formed by stranding a plurality of tinned copper wire bunches, and the stranding direction of the bunch stranding unit is the same as that of the bunch wire units. The cable has the advantages that the metal shielding layer is directly connected to the grounding device, cost is reduced, additional independent grounding wires or other grounding structures are omitted, the cable structure is remarkably simplified, raw material and manufacturing cost is reduced, meanwhile, connection points between the shielding layer and the grounding wire core in a traditional structure do not exist, and cost is reduced. The risk of connection point failure is thoroughly eliminated, and the electrical continuity and long-term reliability of the grounding path of the shielding layer are ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of middle voltage rubber jacketed flexible cable with twisted sparse winding shielding structure, specifically to a kind of rubber jacketed flexible cable suitable for middle voltage usually refers to 6kV-35kV power transmission, belong to power cable technical field. BACKGROUND

[0002] The middle voltage power cable usually needs to be provided with a metal shielding layer for homogenizing electric field distribution, preventing partial discharge, and providing a fault current path. The traditional shielding structure usually adopts copper tape wrapping or copper wire sparse winding. The shielding cross section is small, the shielding resistance is large, the shielding copper tape or copper wire cannot play the role of grounding conductor during installation and construction, and the grounding treatment mode needs to be considered separately during laying. This structure has the following disadvantages:

[0003] 1. Complex structure, high cost: additional grounding wire or other grounding structure design is needed, which increases the installation diameter, weight and raw material cost of the cable.

[0004] 2. Connection reliability risk: the shielding layer and the grounding wire core need to be connected by welding, crimping or winding. The connection point may fail due to vibration, bending or corrosion during subsequent use, resulting in poor grounding.

[0005] 3. Limited flexibility: the additional grounding wire core and connection point may affect the overall flexibility of the cable, especially for soft cable applications that need to be frequently moved or bent. UTILITY MODEL CONTENT

[0006] The utility model aims to provide a kind of middle voltage rubber jacketed flexible cable with twisted sparse winding shielding structure, simple structure, more reliable grounding, better flexibility, solve the above problems existing in background technology.

[0007] The technical solution of the utility model is:

[0008] A kind of middle voltage rubber jacketed flexible cable with twisted sparse winding shielding structure, comprising a metal shielding layer twisted on the core, the metal shielding layer is twisted by a plurality of bundle twisting units, and a gap is left between adjacent two bundle twisting units;The bundle twisting unit is twisted by a plurality of bundle wire units, and the bundle wire unit is twisted by a plurality of tinned copper wire bundles, and the twisting directions of the bundle twisting unit and the bundle wire unit are the same.

[0009] Further, the bundle twisting unit is twisted by a plurality of bundle wire units according to 12 times pitch ratio left direction, and the bundle wire unit is twisted by a plurality of tinned copper wire single wires according to 16 times pitch ratio left direction.

[0010] Further, the core comprises a cable conductor, a conductor shield layer, an insulation layer and an insulation shield layer, the cable conductor is extruded with the conductor shield layer, the conductor shield layer is extruded with the insulation layer, the insulation layer is extruded with the insulation shield layer, and the metal shield layer is twisted outside the insulation shield layer.

[0011] Further, the metal shield layer is wrapped outside the isolation layer, and the isolation layer is extruded with the sheath.

[0012] Further, the gap between two adjacent bundle twisting units is not greater than 4mm.

[0013] The positive effect of the utility model is: the metal shield layer of the cable is directly connected to the grounding device, the cost is reduced: the additional independent grounding wire or other grounding structure is saved, the cable structure is obviously simplified, the raw material and manufacturing cost are reduced, meanwhile, there is no connecting point between the shield layer and the grounding core in the traditional structure, the risk of connecting point failure is completely eliminated, the electrical continuity and long-term reliability of the shield layer grounding path are ensured. The metal shield layer of the application is twisted by tinned copper wires, has good flexibility, makes the overall bending performance of the cable good, and is especially suitable for occasions requiring movement or bending. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a bundle wire unit structure schematic view of the utility model;

[0015] Figure 2 It is a structure schematic view of the utility model;

[0016] In the figure: cable conductor 1, conductor shield layer 2, insulation layer 3 and insulation shield layer 4, insulation shield layer 4, metal shield layer 5, bundle wire unit 51, bundle twisting unit 52, isolation layer 6, sheath 7. DETAILED DESCRIPTION

[0017] The utility model will be further explained in connection with the drawings and examples:

[0018] A kind of medium voltage rubber sheath flexible cable with twisted sparse winding shield structure, it comprises metal shield layer 5 twisted in the core, the metal shield layer 5 is twisted by multiple bundle twisting units 52, and gap is left between two adjacent bundle twisting units 52;Bundle twisting unit 52 is twisted by multiple bundle wire units 51, and bundle wire unit 51 is twisted by multiple tinned copper wire bundles, and the twisting direction of bundle twisting unit 52 and bundle wire unit 51 is same.

[0019] The bundle twisting unit 52 is twisted by multiple bundle wire units 51 according to 12 times pitch diameter ratio left direction, and the bundle wire unit 51 is twisted by multiple tinned copper wire single lines according to 16 times pitch diameter ratio left direction.

[0020] The cable core comprises a cable conductor 1, a conductor shielding layer 2, an insulation layer 3, and an insulation shielding layer 4, the cable conductor 1 is extruded with the conductor shielding layer 2, the conductor shielding layer 2 is extruded with the insulation layer 3, the insulation layer 3 is extruded with the insulation shielding layer 4, and a metal shielding layer 5 is twisted outside the insulation shielding layer 4.

[0021] Referring to the accompanying drawings Figure 2 In the embodiment, the cable conductor 1 is a conductive core twisted by a plurality of metal wires, the metal wires are tin-plated copper wires or copper wires, preferably tin-plated or bare copper 5 copper conductors. The cable conductor 1 is extruded with the conductor shielding layer 2, the conductor shielding layer 2 is a semi-conductive layer tightly wrapped around the conductor surface; the shielding layer 2 is extruded with the insulation layer 3, the insulation layer 3 is a polymer insulation layer, for example, ethylene propylene rubber EPR; the insulation layer 3 is extruded with the insulation shielding layer 4 and tightly wrapped with the insulation layer 3, which is easy to peel off in cold state, the insulation shielding layer 4 is a semi-conductive layer tightly wrapped around the insulation layer 3 surface; the insulation shielding layer 4 is twisted with the metal shielding layer 5 outside, which meets the shielding and plays the role of electrical grounding. The metal shielding layer 5 is wrapped with the isolation layer 6, the isolation layer 6 is a thin layer of non-hygroscopic material, mainly plays the role of isolation, buffering and other functions, effectively protects the metal shielding layer, and also plays the role of isolation with the sheath. The isolation layer 6 is extruded with the sheath 7, the sheath 7 is a rubber sheath, preferably a rubber material with good mechanical properties, wear resistance, weather resistance and flexibility, for example, chlorinated polyethylene CPE, which maintains the softness of the cable, protects the internal structure of the cable, and ensures the stability of the internal structure after the sheath 7 is extruded, has good mechanical properties and comprehensive protection performance, improves the safety protection of the cable and prolongs the service life of the cable.

[0022] The metal shielding layer 5 is directly wrapped outside the insulation shielding layer 4. The metal shielding layer 5 has a high coverage rate, usually ≥80%, preferably 90%-95%, forming a continuous, uniform and good conductive metal shielding.

[0023] Referring to Fig. 1, the metal shielding layer 5 is twisted by a plurality of bundle twisting units 52, the bundle twisting units 52 in the metal shielding layer 5 are regularly and orderly wound on the insulation shielding layer 4 during or after twisting, the gap between adjacent two bundle twisting units 52 is not more than 4mm, and the whole constitutes a twisted loose shielding structure, and the overall cross section meets the standard requirement of the grounding conductor cross section area, directly grounding and draining, and ensuring the reliability of the cable operation.

[0024] The bundle wire unit 1 is twisted by a plurality of tin-plated copper wires according to a 16 times pitch ratio, and the bundle wire unit 1 is twisted by a plurality of bundle wire units 1 according to a 12 times pitch ratio, the bundle wire unit 1 is twisted in the same direction as the bundle wire unit 1, the structure is compact, and the softness of the shielding wire is ensured after twisting.

[0025] The utility model has the advantages that:

[0026] Simplified structure, reduced cost: The additional independent grounding wire or other grounding structure is omitted, the cable structure is significantly simplified, and the raw material and manufacturing cost are reduced.

[0027] Reliable grounding height: The grounding lead is directly derived from the metal shielding layer itself (i.e. the tinned copper wire after twisting), and the two are integrated, and there is no connection point between the shielding layer and the grounding wire core in the traditional structure. This completely eliminates the risk of connection point failure, ensuring the electrical continuity and long-term reliability of the shielding layer grounding path.

[0028] Excellent flexibility: The shielding structure composed of traditional copper wires is hard. The metal shielding layer of the present application is twisted from tinned copper wires, has good flexibility, and cooperates with the rubber outer sheath, so that the overall bending performance of the cable is good, and it is especially suitable for occasions that need to be moved or bent.

[0029] Advantages of tinned copper wire: The use of tinned copper wire as the material of the metal shielding layer enhances the corrosion resistance, especially the sulfidation ability, and improves the stability of long-term use.

[0030] Convenient installation: Because the cross-sectional area of the twisted metal shielding layer is increased, its cross-sectional area meets the standard requirement of the grounding conductor cross-sectional area, so when installing, the metal shielding layer only needs to be directly connected to the grounding device, saving the step of finding and connecting the shielding layer on site, and improving the construction efficiency.

Claims

1. A medium voltage rubber jacketed flexible cable having a twisted and loosely stranded shielding structure, characterized in that: The metal shielding layer (5) is twisted outside the wire core, the metal shielding layer (5) is twisted by a plurality of bundle twisting units (52), and a gap is left between two adjacent bundle twisting units (52); the bundle twisting unit (52) is twisted by a plurality of wire bundle units (51), the wire bundle unit (51) is twisted by a plurality of tinned copper wire bundles, and the twisting directions of the bundle twisting unit (52) and the wire bundle unit (51) are the same.

2. A medium voltage soft cable with a twisted and loosely wound shielding structure according to claim 1, characterized in that: The bundle twisting unit (52) is twisted by a plurality of wire bundle units (51) at a 12-fold pitch ratio left, and the wire bundle unit (51) is twisted by a plurality of tinned copper wire bundles at a 16-fold pitch ratio left.

3. A medium voltage soft cable with a twisted and loosely wound shielding structure according to claim 1 or 2, characterized in that: The wire core comprises a cable conductor (1), a conductor shielding layer (2), an insulation layer (3) and an insulation shielding layer (4), the cable conductor (1) is extruded to cover the conductor shielding layer (2), the conductor shielding layer (2) is extruded to cover the insulation layer (3), the insulation layer (3) is extruded to cover the insulation shielding layer (4), and the metal shielding layer (5) is twisted outside the insulation shielding layer (4).

4. A medium voltage soft cable with a twisted and loosely wound shielding structure according to claim 1 or 2, characterized in that: The metal shielding layer (5) is wrapped with an isolation layer (6), and the isolation layer (6) is extruded with a sheath (7).

5. A medium voltage soft cable with a twisted and loosely wound shielding structure according to claim 1 or 2, characterized in that: The gap between two adjacent bundle twisting units (52) is not more than 4 mm.

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