CN218975190U - Guiding and detecting fault medium voltage cable - Google Patents

Abstract

The utility model discloses a guiding and detecting fault medium voltage cable, which comprises three power insulation wire cores, a pair of guiding wires, a filling strip and an outer sheath, wherein the three power insulation wire cores are connected with the filling strip; the three power insulation wire cores are mutually attached; the pair of guide wires are arranged in the middle of the three power insulation wire cores and are attached to the three power insulation wire cores; the outer sheath is arranged at the periphery of the three power insulation wire cores; the filling strips are filled between the three power insulation wire cores and the outer sheath. According to the scheme, the twisted pair wire cores for guiding and detecting are additionally arranged in the gaps of the three-phase cables, so that the fault points of the cables can be detected rapidly, and the reliability of the medium-voltage cables is improved greatly.

Description

Guiding and detecting fault medium voltage cable

Technical Field

The utility model relates to the technical field of cables, in particular to a medium-voltage power cable and a line fault detection technology.

Background

Along with the acceleration of the construction steps of the Chinese electric power system, the requirements of electric power equipment and accessories are driven, the demand of wires and cables is increased along with the acceleration, the middle-voltage electric power interval tunnel, the subway station, the factory building, the power plant, the intelligent building, the airport and the like are constructed, and the demands of the middle-voltage electric power cables are vigorous.

As the demand for cables increases, so does the number of cable failures, particularly for high economic objectives, the power safety supply, once the medium voltage cable fails. A single-chip power interruption is caused, resulting in a large economic loss. When a cable fails, the difficulty in detecting the failure position and maintaining is increased due to the limitation of topography factors, equipment factors, personnel factors, economic factors and the like, so that the cable is required to have better cable failure detection and action requirements, a standby cable is started, and uninterrupted power connection is ensured.

Thus, the above-mentioned drawbacks greatly reduce the reliability of the medium voltage power cable, and it can be seen how to improve the reliability of the medium voltage power cable is a problem to be solved in the art.

Disclosure of Invention

Aiming at the technical problem of low reliability of the existing medium voltage power, the utility model aims to provide a guiding and detecting fault medium voltage cable, which ensures the reliability of the medium voltage cable and well overcomes the problems in the prior art.

In order to achieve the above purpose, the utility model provides a guiding and detecting fault medium voltage cable, which comprises three power insulation wire cores, a pair of guiding wires, a filling strip and an outer sheath; the three power insulation wire cores are mutually attached; the pair of guide wires are arranged in the middle of the three power insulation wire cores and are attached to the three power insulation wire cores; the outer sheath is arranged at the periphery of the three power insulation wire cores; the filling strips are filled between the three power insulation wire cores and the outer sheath.

Further, the three power insulation wire cores respectively comprise a conductor, a buffer layer, an insulation layer and a metal shielding layer; the buffer layer is coated on the periphery of the conductor; the insulating layer is coated on the periphery of the buffer layer; the metal shielding layer is coated on the periphery of the insulating layer.

Further, the insulating layer is formed by three layers of co-extrusion of a semi-conductive inner shielding layer, a crosslinked polyethylene insulating layer and a semi-conductive outer shielding layer.

Further, the buffer layer is a semiconductive water blocking tape layer.

Further, the metal shielding layer is a copper wire sparse winding and copper strip gap winding composite shielding layer.

Further, the guide wire is a 6 th tinned copper conductor and a thin insulating layer of poly-perfluoroethylene propylene; the poly-perfluoroethylene propylene thin insulating layer is coated on the periphery of the 6 th tinned copper conductor.

Further, the outer sheath is a weather-proof halogen-free low-smoke flame-retardant sheath.

According to the guide detection fault medium-voltage cable, the twisted pair wire cores for guide detection are added in the gaps of the three-phase cables, so that the fault point of the cable can be detected quickly, and the reliability of the medium-voltage cable is improved greatly.

Drawings

The utility model is further described below with reference to the drawings and the detailed description.

Fig. 1 is a schematic diagram of the overall structure of the guide fault detection medium voltage cable.

The following is a description of the components in the drawings:

1. conductor 2, insulating layer 3, buffer layer 4, filler strip 5, metal shielding layer 6, pilot wire 7, and outer sheath.

Detailed Description

The utility model is further described with reference to the following detailed drawings in order to make the technical means, the creation characteristics, the achievement of the purpose and the effect of the implementation of the utility model easy to understand.

Aiming at the technical problem that the reliability of the existing medium-voltage power is low, based on the technical problem, the utility model provides a guide detection fault medium-voltage cable, which can rapidly detect a cable fault point by adding a guide detection twisted wire core in a three-phase cable gap, and greatly improves the reliability of the medium-voltage cable.

Referring to fig. 1, the pilot-detected fault medium voltage cable provided by the utility model comprises three power insulation wire cores, a pair of pilot wires 6, a filling strip 4 and an outer sheath 7.

The three power insulation wire cores respectively comprise a conductor 1, an insulation layer 2, a buffer layer 3 and a metal shielding layer 5.

Further, the 2 nd stranded round compressed copper conductor is adopted as the conductor 1, so that the bending performance of the stranded conductor is improved, the tensile force is enhanced, and the stranded structure has good stability.

The insulating layer 2 is coated on the periphery of the conductor 1, and the insulating layer 2 is formed by co-extrusion of three layers of a semi-conductive inner shielding layer, a crosslinked polyethylene insulating layer and a semi-conductive outer shielding layer.

External impurities can be prevented from being introduced between the crosslinked polyethylene insulating layer and the semiconductive inner shield and the semiconductive outer shield respectively by three-layer coextrusion.

And the semi-conductive inner shielding layer, the semi-conductive outer shielding layer and the crosslinked polyethylene insulating layer can be tightly combined together, so that the initial free discharge voltage is improved.

In addition, the semi-conductive inner shielding layer and the semi-conductive outer shielding layer can prevent gaps from being formed between the conductor and the crosslinked polyethylene insulating layer and between the crosslinked polyethylene insulating layer and the semi-conductive inner shielding layer and between the crosslinked polyethylene insulating layer and the semi-conductive outer shielding layer, so that point discharge is caused, and wire core breakdown is effectively prevented.

Further, the insulating layer 2 adopts a crosslinked polyethylene insulating layer, so that creep resistance, heat resistance and chemical stability can be enhanced, and the electric resistance strength can be improved.

The buffer layer 3 is coated on the periphery of the insulating layer 2, adopts a semiconductive water blocking tape layer, and has the characteristics of strong hygroscopicity, high expansion rate, small product resistance, semiconductive property, effective buffer, weakening of electric field intensity and high mechanical strength.

The metal shielding layer 5 is coated on the periphery of the insulating layer 2, adopts copper wires to form a sparse winding and copper strip gap winding composite shielding, and mainly plays a role in electromagnetic interference to the outside, and prevents interference to the surrounding environment and fault current passing due to electromagnetic fields generated by the metal shielding layer in the use process.

The pair of guide wires 6 are arranged in the middle of the three power insulation wire cores and are respectively attached to the three power insulation wire cores.

The guide wire 6 adopts a 6 th tinned copper conductor, the nominal section is 1mm < 2 >, the thickness of the extruded perfluoroethylene propylene thin insulating layer is 0.5mm, and the two red blue insulating wire cores are directly twisted.

The guide wire 6 is not provided with a shielding layer and a protective layer, so that the thermal resistance and the electromagnetic induction distance are reduced, and the induction efficiency is improved; meanwhile, the 6 th tinned copper conductor has good flexibility, corrosion resistance and oxidation resistance;

and secondly, the thin insulating layer of the poly (perfluoroethylene propylene) has good conductor flexibility, corrosion resistance and oxidation resistance, and the thin insulating layer of the poly (perfluoroethylene propylene) has excellent electrical insulation performance and excellent chemical stability. Particularly, the insulation temperature resistance grade reaches 200 ℃, the transmission performance is not affected under the middle heat of three phase lines, even under the condition of cable faults, the performance is not reduced, the service life is long, and the circuit is not broken; the power cable fault detection device has the advantages that the power cable fault detection device plays a role in detecting when the cable faults, and when the phases of the three power insulation wire cores and the guide wire are different, the fault point position of the power cable is detected.

Specifically, when the cable is in normal load operation, three power insulation wire cores are symmetrical in three-phase alternating current, the sum of currents is close to zero, an electric field is in a balanced state, induced voltage of a guide wire 6 to the power insulation wire cores is small, when one phase in the cable breaks down, positive and negative sequence impedance and zero sequence impedance of the electric field can generate components, the sum of currents is not zero, balance breaks, electric field synthesis generates deformity due to mutual induction, the phase of current and voltage changes, the guide wire 6 also generates larger induced fault voltage, after receiving information by a connecting instrument, a fault line is cut off, and the cable automatically jumps to a standby cable to operate, so that uninterrupted power is ensured.

Compared with the existing optical fiber detection, the guide wire 6 adopted by the scheme has the advantages of simple instrument, low cost, no need of a photoelectric converter, quick response, high temperature resistance, long service life and strong reliability, and the optical fiber is easy to break due to the fact that the residual length of the optical fiber is larger under the influence of high temperature (the temperature is higher during failure).

The metal shielding layer 5 is coated on the periphery of the three power insulation wire cores, adopts copper wires to wind around and copper strips to form a gap package composite shielding, and mainly plays a role in electromagnetic interference to the outside, and prevents interference to the surrounding environment and fault current passing due to electromagnetic fields generated by the metal shielding layer in the use process.

A filling strip 4 is arranged between the metal shielding layer 5 and the outer sheath 7, and the filling strip 4 is used for separating the metal shielding layer 5 from the outer sheath 7 and protecting the metal shielding layer 5.

The filler strip 4 adopts a sector filler strip, has excellent tensile strength, is waterproof and dampproof, is filled in gaps of the three-phase wire cores in a cabling way, fixes the positions of the wire cores to ensure that the cable is round, is fastened by a water blocking belt and an alkali-free glass fiber belt after being cabled, absorbs moisture to form water blocking gel after encountering the moisture and rapidly expands for water blocking; the alkali-free glass fiber tape has good insulating property, no halogen, no smoke, no toxicity, pure oxygen incombustibility and strong flame retardant property.

The outer sheath 7 is coated on the periphery of the filling strip 4, adopts a weather-proof halogen-free low-smoke flame-retardant sheath, and has good weather resistance, flame retardance, environmental protection and higher volume resistivity. When a fire disaster occurs, a large amount of dense smoke and toxic gas are not generated, and the oxygen index is high, so that the combustion is difficult.

The guiding and detecting fault medium-voltage cable formed by the scheme uses the high-temperature high-insulation guide wire to detect the longitudinal difference of the fault on line, the guide wire is reasonable in placement position and is close to the three-phase wire core, the information of detecting induced voltage can be directly and quickly achieved, and the instrument action is promoted to be switched.

The foregoing has shown and described the basic principles, principal features and advantages of the utility model. It will be understood by those skilled in the art that the present utility model is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present utility model, and various changes and modifications may be made without departing from the spirit and scope of the utility model, which is defined in the appended claims. The scope of the utility model is defined by the appended claims and equivalents thereof.

Claims (7)

1. The medium voltage cable for guiding and detecting faults is characterized by comprising three power insulation wire cores, a pair of guide wires, a filling strip and an outer sheath; the three power insulation wire cores are mutually attached; the pair of guide wires are arranged in the middle of the three power insulation wire cores and are attached to the three power insulation wire cores; the outer sheath is arranged at the periphery of the three power insulation wire cores; the filling strips are filled between the three power insulation wire cores and the outer sheath.

2. The pilot-detected fault medium voltage cable of claim 1, wherein the three power insulated wire cores each comprise a conductor, a buffer layer, an insulation layer and a metallic shielding layer; the buffer layer is coated on the periphery of the conductor; the insulating layer is coated on the periphery of the buffer layer; the metal shielding layer is coated on the periphery of the insulating layer.

3. The guided fault detection medium voltage cable of claim 2, wherein the insulation layer is a three-layer co-extrusion of a semiconductive inner shield, a crosslinked polyethylene insulation, and a semiconductive outer shield.

4. The pilot-detected fault medium voltage cable of claim 2, wherein the buffer layer is a semiconductive water blocking tape layer.

5. The guided fault detection medium voltage cable of claim 2, wherein the metallic shield is a copper wire sparse wrap plus copper tape gap wrap composite shield.

6. The pilot-detected fault medium voltage cable of claim 1, wherein the pilot wire is a 6 th tinned copper conductor and a thin insulation layer of poly perfluoroethylene propylene; the poly-perfluoroethylene propylene thin insulating layer is coated on the periphery of the 6 th tinned copper conductor.

7. The pilot-detected fault medium voltage cable of claim 1 wherein the outer jacket is a weatherable halogen-free low smoke flame retardant jacket.

Images