CN211654392U - Rated voltage fireproof frequency conversion cable - Google Patents
Rated voltage fireproof frequency conversion cable Download PDFInfo
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- CN211654392U CN211654392U CN202020510755.7U CN202020510755U CN211654392U CN 211654392 U CN211654392 U CN 211654392U CN 202020510755 U CN202020510755 U CN 202020510755U CN 211654392 U CN211654392 U CN 211654392U
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Abstract
A rated voltage fireproof frequency conversion cable comprises a cable core formed by a plurality of insulating wire cores, wherein each insulating wire core comprises a conductor, a conductor shielding layer, a crosslinked polyethylene insulating layer, an insulating shielding layer and a metal shielding layer are sequentially arranged outside the conductor from inside to outside, and an isolation cooling layer, a wrinkle metal layer, a fireproof mud layer and a low-smoke zero-halogen outer sheath layer are sequentially arranged on the outer surface of the cable core from inside to outside; the insulation shielding layer is a crosslinked semi-conducting layer; the metal shielding layer consists of copper wires loosely wound on the outer surface of the insulating shielding layer and copper strips wound in gaps. The utility model provides a rated voltage fire prevention variable frequency cable can solve the contradiction between current fire resisting cable electrical property and the fire resisting property, not only has good electrical property, still has good fire resisting property.
Description
Technical Field
The utility model belongs to the technical field of the cable technique and specifically relates to a rated voltage 8.7/15kV frequency conversion cable that prevents fires.
Background
In recent years, the variable frequency speed regulation device becomes a central equipment of electric transmission by virtue of the remarkable advantages of energy conservation, labor saving and easy automatic control, and the variable frequency speed regulation technology is promoted to be more and more widely applied to various industries. At present, the voltage class of the fire-resistant cable is 1kV or below, the fire-resistant test is according to the national standard GB/T19216-2003 (equivalent to IEC 60331-1999), and the safety performance of the fire-resistant cable cannot be guaranteed in some occasions requiring medium-high voltage power transmission and distribution because the fire-resistant cable does not exist. The existing fire-resistant cable generally adopts a structure that a conductor is wrapped with a fire-resistant mica tape or a copper core copper sheath magnesium oxide insulated cable is adopted, the former mica tape is generally made of mica paper, alkali-free glass fiber cloth and silicate adhesives and generates an insoluble and infusible hard shell after encountering fire, thereby achieving the purpose of fire resistance, and the latter mica tape adopts mineral magnesium oxide as insulation and cannot be burnt when catching fire; the two fire-resistant cables are characterized in that an inorganic fire-resistant layer is coated outside the conductor to achieve the purpose of fire resistance. And the medium-high voltage cable cannot adopt the structure to realize fire resistance due to the particularity of performance requirements.
Disclosure of Invention
The utility model aims to solve the technical problem that a rated voltage fire prevention variable frequency cable is provided, can solve the contradiction between current fire resisting cable electrical property and the fire resisting property, not only has good electrical property, still has good fire resisting property.
In order to solve the technical problem, the utility model discloses the technical scheme who adopts is: a rated voltage fireproof frequency conversion cable comprises a cable core formed by a plurality of insulating wire cores, wherein each insulating wire core comprises a conductor, a conductor shielding layer, a crosslinked polyethylene insulating layer, an insulating shielding layer and a metal shielding layer are sequentially arranged outside the conductor from inside to outside, and an isolation cooling layer, a wrinkle metal layer, a fireproof mud layer and a low-smoke zero-halogen outer sheath layer are sequentially arranged on the outer surface of the cable core from inside to outside;
the insulation shielding layer is a crosslinked semi-conducting layer;
the metal shielding layer consists of copper wires loosely wound on the outer surface of the insulating shielding layer and copper strips wound in gaps.
The conductor is composed of bare annealed copper wires meeting the GB/T3956 specification, and is subjected to layered compression molding during stranding, and the compression coefficient is not less than 0.9.
In the metal shielding layer, the sparse winding pitch of the copper wire is 14-18 times of the shielding outer diameter of the copper wire, and the sparse winding direction is the left direction; the surface of the copper wire is fastened by a right-hand lapped copper strip.
The cabling pitch-diameter ratio is 25-30.
The corrugated metal layer is a corrugated copper layer, and the inner wall of the corrugated copper layer is attached to the inner layer of the cable.
The utility model discloses the design principle of structure as follows:
1. conductor structure design
A2-type stranded conductor meeting the GB/T3956-2008 requirement is generally adopted for the low-voltage variable-frequency power cable, but the voltage level of the 8.7/15kV cable is high, so that a compact circular structure is adopted for the conductors specified in GB/T12706.2-2008, the uniform distribution of an electric field can be obviously improved, and the insulation quality is prevented from being damaged by point discharge.
2. Insulation design
To selecting for use general power cable, like XLPE insulating polyvinyl chloride sheath cable, because the withstand voltage level of cable itself is higher, seldom take place the breakdown of cable body, but why can long-term operation under the power frequency and breakdown within a few hours under the frequency conversion, the fact proves that this is never ageing problem, can be attributed to the high-frequency impulse voltage impact's the reason basically.
Since the frequency of the high-order harmonic is 3 to 8 times of the fundamental wave, the ratio of the impedance generated by the inductor and the capacitor is much larger than that of the fundamental wave, which is enough to give attention to the reactive loss. The frequency control range of the variable frequency power supply is wide, and the variable frequency power supply has a waveform profile with main frequency no matter the frequency is high or low. The cable comprises a plurality of higher harmonics, the higher harmonics are used as a traveling wave, the amplitude superposition can reach a plurality of times of working voltage after multiple reflections, the longer the cable is, the higher the amplitude is, and the cable can be punctured if the insulation safety coefficient of the cable is not high. In order to enable the cable to be capable of safely transmitting at a long distance, the 8.7/15kV frequency conversion cable is required to have excellent insulating property, so that the thickness of the 8.7/15kV cable is properly thickened, a high-dielectric XLPE material with the thickness of 5.5mm is adopted as the insulation of the frequency conversion cable, a three-layer co-extrusion mode of conductor shielding, insulation and insulation shielding is adopted, the interlayer is smooth, an electric field is homogenized, the insulating property is improved, and the impact of high-frequency pulse reflection superposed voltage can be met.
3. Design of symmetry
The cable between the frequency converter and the variable frequency motor has the advantages that due to the asymmetric structure balance, an electric field and a magnetic field of the cable are always in an unbalanced state, the transmission impedance is high, and the transmission amount of higher harmonics is large. Require the cable to necessarily adopt electric symmetry's structure, ordinary power cable is the stranding after using the copper strips shielding with three insulation core, and the utility model discloses a dredge around adding copper strips reverse clearance around crowded package split-phase sheath behind the package shielding by the copper wire, then the symmetry stranding. The good symmetrical cable structure has better electromagnetic compatibility, can inhibit electromagnetic wave interference and improves the anti-interference performance of the cable.
4. Shielding structure design
The cable shield adopts a structure of split-phase shield and total shield, and the split-phase shield generally adopts a shielding mode of combining copper wire loose winding and copper strip reverse fastening as described above; the total shielding structure adopts the wrinkle copper sheath, has realized the totally enclosed shielding effect of whole cable, and the shielding inhibition factor is less than 0.01, can restrain higher harmonic, electromagnetic radiation and conduction effectively, has reached the symmetry balance of each electric parameter of cable, and under the state (including various electric parameters such as inductance, electric capacity) containing higher balance, transmission impedance is low, high harmonic emission is little. The cable is in the optimum and gives full play to its insulation level, guarantees to keep the stable performance under the high-frequency pulse emission effect, safe and reliable to have good comprehensive properties, adapt to multiple environment of laying, guarantee that the cable operation is reliable for a long time.
5. Other structures and materials are selected. In order to ensure that the electrical insulation performance and other performances of the cable meet the requirements of national standards, other structures and materials meet the standard regulation of GB/T12706.2-2008.
The utility model provides a rated voltage frequency conversion cable that prevents fires, beneficial effect as follows:
1. when a fire disaster happens, the cable normally works within the specified 90min through the combined action of the flame-retardant layer, the fireproof layer, the heat-insulating and oxygen-insulating layer and the oxygen-insulating and temperature-reducing layer, so that the aim of fire resistance is fulfilled.
2. The heat insulation and oxygen isolation layer adopts the corrugated copper sheath, so that the fire barrier layer can isolate oxygen, the complete sealing and shielding effect of the whole cable can be realized, and the shielding inhibition coefficient is less than 0.01.
3. The outer sheath layer is made of low-smoke halogen-free flame-retardant polyolefin with the oxygen index larger than 36, the material can emit a large amount of moisture under the high-temperature condition, the moisture can absorb a large amount of heat by evaporation, and meanwhile, the material has a flame-retardant effect, does not generate toxic and harmful substances during combustion, and is not harmful to a human body.
The cable can solve the contradiction between the electrical performance and the fire resistance of the existing fire-resistant cable, and has excellent electrical performance and good fire resistance.
The cable is tested, and the result shows that the cable has excellent performance indexes which all meet the design requirements:
drawings
The invention will be further explained with reference to the following figures and examples:
fig. 1 is a schematic structural diagram of the present invention.
Detailed Description
As shown in fig. 1, a rated voltage fireproof frequency conversion cable comprises a cable core formed by a plurality of insulating wire cores, wherein each insulating wire core comprises a conductor 1, a conductor shielding layer 2, a crosslinked polyethylene insulating layer 3, an insulating shielding layer 4 and a metal shielding layer 5 are sequentially arranged outside the conductor 1 from inside to outside, and an isolation cooling layer 6, a corrugated metal layer 7, a fireproof mud layer 8 and a low smoke zero halogen outer sheath layer 9 are sequentially arranged on the outer surface of the cable core from inside to outside;
the insulation shielding layer 4 is a crosslinked semiconductive layer;
the metal shielding layer 5 is composed of copper wires loosely wound on the outer surface of the insulating shielding layer 4 and copper strips wound in gaps.
The conductor is composed of bare annealed copper wires meeting the GB/T3956 specification, and is subjected to layered compression molding during stranding, and the compression coefficient is not less than 0.9.
In the metal shielding layer 5, the sparse winding pitch of the copper wire is 14-18 times of the shielding outer diameter of the copper wire, and the sparse winding direction is the left direction; the surface of the copper wire is fastened by a right-hand lapped copper strip.
The cabling pitch-diameter ratio is 25-30.
The corrugated metal layer 7 is a corrugated copper layer, and the inner wall of the corrugated copper layer is attached to the inner layer of the cable.
The utility model discloses a manufacturing process and main points are as follows:
1. the conductor 1 consists of a bare annealed copper wire in accordance with GB/T3956 (the purity of copper is more than or equal to 99.97%). In the manufacturing process of the cable conductor, an oxygen-free copper rod is manufactured by an up-drawing production line, and a single wire is drawn by an import large drawing machine with continuous annealing. The conductor 1 is formed by layer pressing during stranding, so that the tightness and the stable structure of the conductor 1 are ensured. The compression coefficient is not less than 0.9, the surface of the conductor is smooth and clean, has no oil stain, has no damage to shielding and insulating burrs and sharp edges, and has no bulge or broken single line.
2. Extrusion crosslinking process
The conductor shielding layer 2, the crosslinked polyethylene insulating layer 3 and the insulating shielding layer 4 adopt a three-layer co-extrusion and totally-closed chemical crosslinking process.
3. Conductor shield layer 2
The extruded conductor shield 2 (semi-conducting layer) should be coated uniformly on the conductor 1, with smooth surface, no obvious twisted wire relief, no sharp corners, particles, scorching or scratching marks. The semiconducting layer should not cause seizing between the strands of conductor when stripping the conductor screen 2.
The conductor shield 2 has a nominal thickness of 0.8mm and the minimum thickness should be no less than 0.64 mm.
The resistivity of the conductor shield layer 2 does not exceed 1000 ohm-meter.
4. Insulation
The insulation is made of cross-linked polyethylene insulation material, the nominal thickness of the insulation is 5.0mm, the average value of the insulation thickness is not less than the nominal value, and the minimum measurement thickness of any point is not less than 4.5 mm.
5. Insulation shield
The insulating shielding layer 4 is an extruded cross-linked semi-conducting layer, the semi-conducting layer is uniformly coated on the insulating surface, and the surface is smooth and has no sharp corners, particles, scorched or scratched traces.
The nominal thickness of the insulating and shielding layer 4 is: 0.8 mm. The minimum thickness should be no less than 0.64 mm. The insulating-shielding layer 4 should be of a peelable type.
The resistivity of the insulating shield layer 4 is not more than 500 ohm-meter.
6. Metal shield
The copper wire shield is composed of loosely wound annealed copper wires, and the annealed copper wires are in accordance with the regulation of GB/T3953-2009. The loose winding pitch of the soft copper wire is 14-18 times of the shielding outer diameter of the copper wire, the loose winding direction is leftward, the surface of the loose winding pitch is tightened by a right-hand wrapped copper strip, the average gap between every two adjacent copper wires is not larger than 4mm, and the gap between every two adjacent copper wires is not larger than 8 mm.
The nominal thickness of the cable copper strip is not less than 0.10mm, and the minimum thickness of the copper strip is not less than 90% of the nominal value.
The copper strip shielding is composed of a layer of soft copper strips wound in a clearance mode, the copper strip winding is smooth, the average clearance rate between the copper strips is not larger than 40% (a nominal value), the defects of curling, scratching and the like are avoided, and the copper strip joint is firm and smooth.
7. Cabling method
The cabling pitch-diameter ratio is controlled to be 25-30, so that the cable core is compact and round after cabling and bending flexibility are guaranteed.
8. Extruded oxygen-insulating cooling layer 6
The extrusion type extrusion-coated tough flame-retardant oxygen-insulating material is adopted, the nominal thickness of the oxygen-insulating and cooling layer 6 is 2mm, the average thickness of the oxygen-insulating and cooling layer is not smaller than the nominal value, and the thinnest thickness of any point is not smaller than 85-0.1 mm of the nominal value. The extruded appearance should be smooth, dense, round.
9. Corrugated metal layer 7
And (3) adopting a copper strip with the thickness of 0.8-1.0 mm, and embossing after longitudinal argon arc welding. The welding seam is required to be sealed and smooth, and the inner wall of the wrinkle is tightly attached to the inner layer of the cable.
10. Extruded fireproof mud layer 8
The magnesium hydroxide material is extruded, the nominal thickness is 3mm, the average thickness of the magnesium hydroxide material is not less than the nominal value, and the thinnest thickness of any point is not less than 85-0.1 mm of the nominal value. The extruded appearance should be smooth, dense, round.
11. Extruded low smoke halogen-free outer sheath layer 9
The oxygen index of the adopted material is not lower than 32, the average thickness of the adopted material is not less than the nominal value, the nominal thickness is 4mm, and the thinnest thickness of any point is not less than 85-0.1 mm of the nominal value. After the sheath is extruded, the appearance should be smooth, dense and round.
The above embodiments are merely preferred technical solutions of the present invention, and should not be considered as limitations of the present invention, and the features in the embodiments and the examples in the present application may be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be defined by the claims and the technical solutions described in the claims, including the technical features of the equivalent alternatives as the protection scope. Namely, equivalent alterations and modifications within the scope of the invention are also within the scope of the invention.
Claims (5)
1. The utility model provides a rated voltage frequency conversion cable that prevents fires, includes the cable core that is formed by many insulation core, its characterized in that: the insulating wire core comprises a conductor (1), a conductor shielding layer (2), a crosslinked polyethylene insulating layer (3), an insulating shielding layer (4) and a metal shielding layer (5) are sequentially arranged outside the conductor (1) from inside to outside, and an isolation cooling layer (6), a wrinkle metal layer (7), a fireproof mud layer (8) and a low-smoke halogen-free outer sheath layer (9) are sequentially arranged on the outer surface of the cable core from inside to outside;
the insulation shielding layer (4) is a crosslinked semi-conducting layer;
the metal shielding layer (5) is composed of copper wires loosely wound on the outer surface of the insulating shielding layer (4) and copper strips wound in gaps.
2. A voltage rated fireproof frequency conversion cable according to claim 1, wherein: the conductor is composed of bare annealed copper wires meeting the GB/T3956 specification, and is subjected to layered compression molding during stranding, and the compression coefficient is not less than 0.9.
3. A voltage rated fireproof frequency conversion cable according to claim 1, wherein: in the metal shielding layer (5), the sparse winding pitch of the copper wire is 14-18 times of the shielding outer diameter of the copper wire, and the sparse winding direction is the left direction; the surface of the copper wire is fastened by a right-hand lapped copper strip.
4. A voltage rated fireproof frequency conversion cable according to claim 1, wherein: the cabling pitch-diameter ratio is 25-30.
5. A voltage rated fireproof frequency conversion cable according to claim 1, wherein: the wrinkled metal layer (7) is a wrinkled copper layer, and the inner wall of the wrinkled copper layer is attached to the inner layer of the cable.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020510755.7U CN211654392U (en) | 2020-04-09 | 2020-04-09 | Rated voltage fireproof frequency conversion cable |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202020510755.7U CN211654392U (en) | 2020-04-09 | 2020-04-09 | Rated voltage fireproof frequency conversion cable |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112710935A (en) * | 2021-03-29 | 2021-04-27 | 华东交通大学 | Power wire and cable protective layer ablation condition pre-alarming system and method |
| CN114446533A (en) * | 2022-03-21 | 2022-05-06 | 河南乐山电缆有限公司 | Rat-proof and ant-proof mineral insulated fireproof cable and preparation method thereof |
-
2020
- 2020-04-09 CN CN202020510755.7U patent/CN211654392U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112710935A (en) * | 2021-03-29 | 2021-04-27 | 华东交通大学 | Power wire and cable protective layer ablation condition pre-alarming system and method |
| CN112710935B (en) * | 2021-03-29 | 2021-06-25 | 吉安诺惠诚莘科技有限公司 | Power wire and cable protective layer ablation condition pre-alarming system and method |
| CN114446533A (en) * | 2022-03-21 | 2022-05-06 | 河南乐山电缆有限公司 | Rat-proof and ant-proof mineral insulated fireproof cable and preparation method thereof |
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