CN202632870U - Medium-voltage fireproof frequency-conversion electric cable - Google Patents

Abstract

The utility model discloses a medium-voltage fireproof frequency-conversion electric cable. An electric cable core is formed by twisting a plurality of metal shielding wire cores and a plurality of neutral wire auxiliary wire cores. The neutral wire auxiliary wire cores are embedded into cable gaps among the metal shielding wire cores. The exterior of the cable core is sequentially provided with a lining layer, a metal shielding layer in a winding mode, and a ceramic silicon rubber fireproof layer and an anti-flaming polyolefin inner protecting sleeve in an extruding mode. A glass fiber belt winding layer covered with ceramic silicon rubber in a coating mode is arranged outside the inner protecting layer in a winding mode. An anti-flaming polyolefin outer protecting sleeve is wrapped around the outermost layer of the electric cable in an extruding mode. The medium-voltage fireproof frequency-conversion electric cable which has no halogen has the advantages of being fireproof, high in conveyed voltage, highly anti-flaming, low in smoke, long in fireproof time, strong in shielding performance, safe, effective, energy-saving, and suitable for connection among a high-voltage large-power frequency-conversion motor, a transducer and a medium-voltage frequency-conversion motor.

Description

The fire-resistant frequency-changing cable of middle pressure

Technical field:

The utility model relates to a kind of middle fire-resistant frequency-changing cable of pressing.

Background technology:

As everyone knows, the low-voltage variable frequency cable is full maturity, and obtains extensive use, and along with industrial expansion, the continuous appearance of middle pressure high-power frequency conversion motor and medium voltage frequency converter must be used the medium voltage converter cable and connected in the medium voltage converter speed regulation process.Because the transmission voltage grade is high, the medium voltage converter cable is simple unlike low-voltage variable frequency cable that kind, because motor is in speed regulation process; Frequency converter provides different frequency power supplys to motor, and this frequency usually is the hundreds of hertz, and the power supply of this frequency can have the waveform profiles of a basic frequency in transmission course; This main outline has also contained many high order harmonic components, and these high order harmonic components propagate as a kind of capable ripple and after repeatedly reflecting, original operating voltage is just high; Can be higher after its amplitude stack, usually reach the several times of operating voltage, cable is long more; Amplitude is high more, and when this amplitude reaches certain multiple, cable holds can't stand and can puncture.Because this kind cable is to be used between control cubicle frequency converter and the variable-frequency motor; It is inner that the cable of this purposes often is laid in industrial and mining enterprises' factory building; Factory building inside and stube cable place often have a lot of equipment and precision instrument; These environment need cable to have fire-resistant, Halogen, low cigarette, fire-retardant, the characteristic that shielding properties is high, safe and effective, energy-conservation.

Summary of the invention:

For overcoming the defective of prior art; The purpose of the utility model is to provide a kind of middle fire-resistant frequency-changing cable of pressing; Be 6kV and above in press fire-resistant frequency-changing cable, that this kind cable has is fire-resistant, transmission voltage is high, high flame retardant, low cigarette, halogen, fire resistance period is long, shielding properties is high, and is safe and effective; Energy-conservation characteristic is highly suitable for being connected usefulness between high-power variable-frequency motor, frequency converter and the medium voltage converter motor.

The utility model technical solution problem adopts following technical scheme:

The fire-resistant frequency-changing cable of middle pressure, cable conductor is by many metallic shield cores and the many stranded strandings of neutral line auxiliary core, and said neutral line auxiliary core is embedded in the stranding gap of said metallic shield core;

Said cable core is provided with inner covering outward successively, is surrounded with metal screen layer, is extruded with potteryization silicon rubber flame retardant coating, fire retardant polyolefin inner sheath; Said inner sheath outside is surrounded with the glass fiber tape lapping layer of coated ceramic silicon rubber, and the outermost layer of cable is extruded with the fire retardant polyolefin oversheath.

Said metallic shield core is three, each metallic shield core by the copper core press round conductor, wrapped in the semiconductive conductor shield on the conductor, extrude in the crosslinked polyetylene insulated layer on the conductor shield, wrappedly constitute in the semiconductive insulation screen on the insulating barrier, wrapped metal copper strips lapping layer on insulation screen.

The naked copper bundle twisted wire that said neutral line boost line core is three same cross-sectional is embedded in the stranding gap of said metallic shield core.Said inner covering is made up of at alkali-free sized glass fibre band on the cable core and the low-smoke halogen-free polyolefin that is extruded on the said glass fiber tape wrapped.Metal screen layer is a copper wire braid and wrapped in the outside wrapped formation of copper strips of said copper wire braid.

Compared with present technology, the beneficial effect of the utility model is embodied in:

1, the utility model copper core low-smoke non-halogen flame-retardant 6kV and the fire-resistant frequency-changing cable all material of above middle pressure all are to adopt halogen-free low-smoke flame retardant material; Particularly inner covering, inside and outside sheath all are high flame resistance, low smoke halogen-free polyolefin materials, and its oxygen index can reach more than 40%, and this kind material tool hangs down cigarette; Halogen; Fire-retardant, halogen, nontoxic characteristic; Adopt halogen-free low-smoke flame retardant material can avoid because of accidents such as fire cause secondary disaster to other precision electronic element of surrounding environment, the product after the burning can not corrode the electronic component of other precision instrument.

2, cable adopts and extrudes potteryization silicon rubber refractory material and the wrapped glass fibre belt combining form that is coated with potteryization silicon rubber refractory material; Adopt the fire-resistant form of this kind combination; The cable fire resistance improves greatly, because every layer of refractory material can play the obstruct of certain hour to cable fire, and every layer material can both play the heat insulation of the inside cable core and oxygen barrier effect; Play double protection, further improved the fire resistance period and the fire-resistant fail safe of cable.

3, metal copper strips lapping layer and three auxiliary naked copper bundle twisted wire core area sums are not less than principal phase line area, and the fail safe that has improved the anti-harmonic wave property of cable is because in the ac cable transmission course; When three-phase current reached balance, its neutral current sum was zero, if triple-frequency harmonics occurs; Then there is not phase difference in the current component of triple-frequency harmonics in the neutral line; Its electric current and non-vanishing directly is superimposed as three times of current component, even higher; If three single-phase variable-frequency motors of the former confession of frequency-changing cable are balances; Then neutral current can be bigger, even can surpass the amount of principal phase line current, so copper strips shielding and three auxiliary naked copper bundle twisted wire core area sums are not less than the conducting that principal phase line area can improve the higher harmonic current component greatly; Current lead-through when accelerating cable fault and other and joining ground short circuit can be protected cable, variable-frequency motor, frequency converter and people's life security.

4, metal screen layer adopts copper cash braiding and the wrapped combination shielding of copper strips, and medium voltage converter cable operating voltage grade is high, and modulation frequency is big; High order harmonic component stack is frequent and amplitude is big, and on every side electronic component all be light current control, the magnetic field that the electric field of frequency change can change; The electromagnetic field of these variations can pollute and misoperation light current control element on every side, adopts the combination shielding, makes the shielding surface of cable reach 100%; The non-electromagnetic field leakage space greatly reduce the medium voltage converter cable to the interference of precision instrument electronic component and radio communication on every side, and its area is not less than 10% of principal phase line area; Increase the shielding area coverage, accelerate the screen induced current and insert underground speed, reduce higher harmonic current and penetrate screen and produce interference; Reduce repeatedly the electromagnetic field that reflection interference produces; The frequency change difference of input cable and cable output is reduced, improved the anti-interference and the interference of frequency-changing cable, improved the authenticity of frequency-changing cable two ends frequency conversion with frequency and transmission; Be response, also reduced the vibrations of variable-frequency motor when frequency conversion simultaneously.

Description of drawings:

Fig. 1 is the structural representation of the utility model.

Label among the figure: 1 conductor, 2 conductor shields, 3 insulating barriers, 4 insulation screens, 5 metal copper strips lapping layers, 6 neutral line auxiliary cores, 7 inner coverings, 8 metal screen layers, 9 flame retardant coatings, 10 inner sheaths, 11 lapping layers, 12 oversheaths.

Below pass through embodiment, and combine accompanying drawing that the utility model is described further.

Embodiment:

Embodiment: referring to Fig. 1; Press round conductor 1 outside at the copper core and extrude semiconductive conductor shield 2; Concentrate and the puncture cable to reduce the most advanced and sophisticated outstanding electric field that causes of conductive surface; The conductor screen laminar surface extrudes peroxide crosslinked polyethylene insulating barrier 3, and insulating barrier 3 surfaces extrude semiconductive insulation screen 4, to reduce insulating surface resistance excessive generation span voltage and flashover; The wrapped copper strips shielding of insulation shielding laminar surface constitutes metal copper strips lapping layer 5; Threephase cable carries out stranding according to certain look preface, and in gap, cable core three place, embeds same cross-sectional naked copper bundle strand neutral line auxiliary core 6 respectively, and naked copper bundle twisted wire should closely contact with metal copper strips lapping layer 5; And the area of naked copper bundle twisted wire and copper strips and the area that is not less than the principal phase line, this auxiliary neutral core and metal copper strips lapping layer can bear the electric current that the triple-frequency harmonics stack appears in cable; The outer high oxygen barrier layer gluing of the wrapped high flame retardant glass fibre belt of cable core; And extrude one deck oxygen index on the glass fibre belt surface and be not less than 40% high flame resistance, low smoke halogen-free polyolefin and constitute inner covering 7 jointly; Braiding copper wire in inner covering outside adds the wrapped formation metal screen layer 8 of copper strips, and to form composite shielding, its shielding surface is not less than 10% of principal phase line area; Metal screen layer 8 outsides extrude potteryization silicon rubber flame retardant coating 9 again; This layer potteryization silicon rubber can form the firm ceramic body of one deck when high-temp combustion, the core of the inside is played heat insulation, the effect of oxygen barrier; The flame retardant coating outside extrudes one deck low-smoke bittern-free highly fire-proof polyolefin inner sheath 10, and this layer oxygen barrier inner sheath has fire-retardant, heat insulation, and the oxygen barrier effect can prolong the time of flame the inside cable core burning; The wrapped glass fiber tape that scribbles potteryization silicon rubber refractory material in inner sheath outside constitutes lapping layer 11, and this kind material has the effect of the fire-resistant and high flame retardant of height, can stop and prolong the burning of flame to the inside cable core certain hour; Outermost extrudes oxygen index and reaches the high flame resistance, low smoke halogen-free anti-flaming polyolefin oversheath 12 on 40%.

Claims (5)

1. the fire-resistant frequency-changing cable of middle pressure is characterized in that:

Cable conductor is by many metallic shield cores and the stranded stranding of many neutral line auxiliary cores (6), and said neutral line auxiliary core is embedded in the stranding gap of said metallic shield core;

Said cable core is provided with inner covering (7) outward successively, is surrounded with metal screen layer (8), is extruded with potteryization silicon rubber flame retardant coating (9), fire retardant polyolefin inner sheath (10); Said inner sheath outside is surrounded with the glass fiber tape lapping layer (11) of coated ceramic silicon rubber, and the outermost layer of cable is extruded with fire retardant polyolefin oversheath (12).

2. press fire-resistant frequency-changing cable in according to claim 1; It is characterized in that; Said metallic shield core is three, each metallic shield core by the copper core press round conductor (1), wrapped in the semiconductive conductor shield (2) on the conductor, extrude in the crosslinked polyetylene insulated layer (3) on the conductor shield (2), wrappedly constitute in the semiconductive insulation screen (4) on the insulating barrier (3), wrapped metal copper strips lapping layer (5) on insulation screen (4).

3. press fire-resistant frequency-changing cable in according to claim 1, it is characterized in that the naked copper bundle twisted wire that said neutral line boost line core is three same cross-sectional is embedded in the stranding gap of said metallic shield core.

4. press fire-resistant frequency-changing cable in according to claim 1, it is characterized in that, said inner covering (7) is made up of at alkali-free sized glass fibre band on the cable core and the low-smoke halogen-free polyolefin that is extruded on the said glass fiber tape wrapped.

5. press fire-resistant frequency-changing cable in according to claim 1, it is characterized in that, metal screen layer (8) is a copper wire braid and wrapped in the outside wrapped formation of copper strips of said copper wire braid.

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