阅读说明：本技术 铁路数字信号电缆 (Railway digital signal cable ) 是由 王子纯 吴荣美 邵秀琴 唐秀芹 陈彩云 袁海峰 于 2019-12-15 设计创作，主要内容包括：本发明公开了一种铁路数字信号电缆,其缆芯至少包括有一星形四线组；在星形四线组的线组内包带层和线组外包带层之间设置有监测电容板组件,每一侧的监测电容板由若干电容板单元构成,各电容板单元的长度均不相等,电容板单元的展角α=90°—120°,电容板单元由电容连接线相互并联；所述线组屏蔽结构包括线组屏蔽波纹带和相互间隔地支撑于线组屏蔽波纹带内的线组屏蔽撑圈；总屏蔽结构包括总屏蔽波纹带和相互间隔地支撑于总屏蔽波纹带内的屏蔽撑圈；铠装层包括绕包的内层绕包钢带和外层绕包钢带,在内层绕包钢带和外层绕包钢带相互搭接段之间嵌装有橡胶密封带。该信号电缆能有效地监测电缆的适时运行状态,且具有良好的抗压,阻水性能。(The invention discloses a railway digital signal cable, wherein a cable core at least comprises a star quad, a monitoring capacitor plate assembly is arranged between a wire group inner wrapping tape layer and a wire group outer wrapping tape layer of the star quad, a monitoring capacitor plate on each side is composed of a plurality of capacitor plate units, the lengths of the capacitor plate units are different, the spread angles of the capacitor plate units are α = 90-120 degrees, the capacitor plate units are connected in parallel through capacitor connecting wires, the wire group shielding structure comprises a wire group shielding corrugated belt and wire group shielding support rings which are supported in the wire group shielding corrugated belt at intervals, the total shielding structure comprises a total shielding corrugated belt and shielding support rings which are supported in the total shielding corrugated belt at intervals, an armor layer comprises an inner layer wrapping steel belt and an outer layer steel belt which are wrapped, and a rubber sealing belt is embedded between the mutually overlapped sections of the inner layer wrapping steel belt and the outer layer wrapping steel belt.)

1. A railway digital signal cable comprises a cable core, and is characterized in that the cable core at least comprises a star quad group (8), the star quad group (8) is formed by twisting four insulated single wires (7), the insulation layers of the insulated single wires (7) are three layers of a solid inner skin layer (72), a middle foam layer (73) and a solid outer skin layer (74) from a conductor (71) to the outside in sequence, a wire group inner wrapping tape layer (81), a wire group outer wrapping tape layer (83), a wire group shielding structure (84) and a wire group outer sheath (85) are sequentially wrapped on the star quad group (8) from the inside to the outside, a monitoring capacitor plate assembly (82) is arranged between the wire group inner wrapping tape layer (81) and the wire group outer wrapping tape layer (83), the monitoring capacitor plate assembly (82) comprises monitoring capacitor plates (821) which are oppositely arranged, the monitoring capacitor plate (821) on each side is formed by a plurality of capacitor plate units (18) which are longitudinally arranged, the lengths of the capacitor plate units (823) are different, the capacitor plate units (823) are all different in length, the spread angle α degrees of the capacitor plate units (821) are formed by overlapping the shielding plate units (822) which are overlapped with the shielding tape units (4) and the corrugated shielding tape structures (18), the shielding tape structures (4) which are overlapped with each other shielding tape units, the shielding tape structures (21) which are overlapped with each other shielding tape structures, the shielding tape structures (21) which are overlapped with the corrugated tape structures, the shielding tape structures, the inner wrapping tape structures (18) which are overlapped with the corrugated tape structures, the corrugated tape structures (4) and the corrugated tape structures (21) which are overlapped with the corrugated tape structures (21) in the corrugated tape structures, 22) which are overlapped with the corrugated tape structures, the corrugated tape.

2. The railway digital signal cable of claim 1, wherein: the lengths of the adjacent capacitor plate units (823) are increased or decreased by multiples along the longitudinal direction, and the lengths of the oppositely arranged capacitor plate units (823) are equal.

3. The railway digital signal cable of claim 1, wherein: the longest capacitor plate unit (823) in the capacitor plate units (823) is located in the middle of the longitudinal direction of the star quad group (8), and the length of each capacitor plate unit (823) from the longest capacitor plate unit (823) to the two longitudinal ends of the star quad group (8) is reduced by multiple; each capacitor plate unit (823) arranged from the middle to two ends of the star quad-set (8) is connected in parallel by a corresponding capacitor connecting line (822).

4. The railway digital signal cable according to claim 2 or 3, wherein the capacitor plate unit (823) has an angular spread of α =100 °.

5. The railway digital signal cable of claim 1, wherein: the line group shielding corrugated belt (841) is a corrugated copper belt, and the line group shielding support ring (842) is embedded in a corrugated groove corresponding to the line group shielding corrugated belt (841).

6. The railway digital signal cable of claim 5, wherein: the wire group shielding support ring (842) is made of carbon fibers, the wire group shielding support ring (842) is composed of a shielding upper support ring (843) and a shielding lower support ring (845), and the shielding upper support ring (843) and the shielding lower support ring (845) are mutually inserted and connected through a support ring tenon (844) and a support ring groove (846).

7. The railway digital signal cable of claim 1, wherein: the total shielding corrugated belt (41) is an embossed copper belt, and the shielding support ring (42) is embedded in a corrugated groove corresponding to the total shielding corrugated belt (41).

8. The railway digital signal cable of claim 7, wherein: the shielding support ring (42) is made of carbon fibers, the shielding support ring (42) is composed of an upper support ring (43) and a lower support ring (45), and the upper support ring (43) and the lower support ring (45) are mutually inserted through an inserting tenon (44) and an inserting groove (46).

9. The railway digital signal cable of claim 1, wherein: the inner layer wrapping steel strips (21) are spirally and alternately wrapped on the inner cushion layer (3); the outer layer of the wrapping steel belt (22) is spirally and alternately wrapped on the inner layer of the wrapping steel belt (21).

10. The railway digital signal cable of claim 9, wherein: the distance between two adjacent sides of the inner layer wrapping steel belt (21) or the outer layer wrapping steel belt (22) which are spirally wrapped is smaller than half of the width of the steel belt.

Technical Field

The invention relates to the technical field of cables, in particular to a railway signal cable for connecting related equipment and control devices in a railway signal system.

Background

The railway signal cable is an electric wire cable which is essential in railway construction and carries signal transmission and energy transmission, is a key component for connecting related equipment and control devices in a railway signal system, and is a nerve center of a railway operation control system. Particularly, along with the continuous speed increasing of the railway and the development trend that the high-speed railway enters digitization, intellectualization and synthesis, the reliability and safety of the railway signal cable are more important for the high-efficiency operation of a high-speed railway system, so that the comprehensive performance of the cable is improved on the basis that the railway digital signal cable meets the indexes of the original railway signal cable, the capacitance index is reduced by 40%, the insulation resistance index is improved by 2.3 times, and the impedance, attenuation and crosstalk performance are optimized.

The internal shielding railway digital signal cable has obvious advantages in digital signal transmission due to the stability and excellent anti-interference performance of transmission signals, occupies a high proportion in the cable consumption of the existing railway construction, and the existing railway digital signal cable mainly has two basic structures, namely an aluminum-polyethylene comprehensive sheath structure cable and an aluminum sheath structure cable, wherein the cable core mainly comprises an internal shielding four-wire set. Along with the continuous acceleration of high-speed railway, the complexity of laying environment, and the further stricter of installation and laying requirements, put forward more stringent requirements to the safe reliability of signal cable operation: firstly, because the stability of the conductor structure and the impedance of the conductor of the inner shielding four-wire group can affect the safe and accurate transmission of the analog signal, the digital signal and the control information of the cable, however, the digital signal cable can be accidentally changed in the positions of the four-wire group four-conductor structure in the manufacturing, laying and running processes, the digital signal cable is irregularly stretched to form a diameter reduction, particularly, the cable can bear larger longitudinal tension when the railway signal cable is in the environments of crossing special terrains or laying terrain creep and the like, the increase of the longitudinal tension can cause the irregular radial shrinkage deformation of the cable conductor, even the four-wire group conductor can be fractured, the result is very dangerous for locomotives running at high speed, and the change of the wire group conductor structure can not be timely monitored and found in the existing railway digital signal cable. The two existing wire group shields are shielding structures formed by wrapping four wire groups with metal foil strips, but signal cables are rolled and bent in laying and using processes, the metal foil strips can not bear the rolling and bending of external force, the rolling and bending formed by the external force can not only damage the stability of the position structure of a four wire group conductor, but also cause the fine flattening and even the fracture of the insulated single wires and the conductors of the wire groups, not only can influence the mechanical strength and the surface smoothness of the insulated single wires, but also can influence the coaxial capacitance, the concentricity and the ellipticity of the insulated single wires, and then influence the electrical property of the cables, and obviously, the shielding structures of the existing four wire groups can not effectively protect the wire group conductor. Thirdly, the use region of the railway digital signal cable is very complicated, especially the signal cable which is in a humid or water corrosion environment for a long time, the aging and cracking of the cable protective layer can cause water or vapor to permeate into the cable, the electrical performance of the cable is easy to be reduced, the conductor is corroded and oxidized, the reliable and accurate transmission of the control signal is seriously influenced, and the use safety and the service life of the signal cable are seriously reduced. Meanwhile, although the metal sheath of the conventional railway digital signal cable has a certain shielding effect, the main function of the sheath is still to protect the cable core, so the shielding performance of the cable is still insufficient, the reliable shielding of physical parameters such as external signals and disordered electromagnetic waves is lacked, the safe and reliable transmission of control signals is directly influenced, and the cable is particularly prominent in high-reliability and high-safety application occasions such as high-speed rails, urban light rails and the like.

Disclosure of Invention

Aiming at the defects in the prior art, the technical problem to be solved by the invention is to provide the railway digital signal cable, which not only can effectively monitor the timely running state of the cable, but also has good compression resistance and water resistance.

In order to solve the technical problem, the railway digital signal cable comprises a cable core, wherein the cable core at least comprises a star-shaped four-wire group, the star-shaped four-wire group is formed by twisting four insulating single wires, the insulating layers of the insulating single wires are three layers of a solid inner skin layer, a middle foam layer and a solid outer skin layer from a conductor to the outside in sequence, a wire group inner wrapping tape layer, a wire group outer wrapping tape layer, a wire group shielding structure and a wire group outer sheath are sequentially wrapped on the star-shaped four-wire group from the inside to the outside, a monitoring capacitor plate assembly is arranged between the wire group inner wrapping tape layer and the wire group outer wrapping tape layer and comprises monitoring capacitor plates which are oppositely arranged, the monitoring capacitor plates on each side are composed of a plurality of capacitor plate units which are longitudinally arranged, the lengths of the capacitor plate units are different, the spread angles of the capacitor plate units are α -90 degrees to 120 degrees, the capacitor plate units on the same sides are mutually connected in parallel through capacitor connecting wires, the wire group shielding structure comprises a shielding corrugated tape and shielding tape supporting rings which are mutually and lapped with the inner and outer steel tape wrapping tape supporting layers, and the armor tape supporting layers are arranged between the armor tape wrapping tape layers, and the armor tape wrapping tape supporting layers, and the armor tape supporting layers are mutually overlapped.

Compared with the prior art, the railway digital signal cable at least has the following remarkable advantages:

the monitoring capacitor plate is characterized in that a monitoring capacitor plate assembly is arranged between the inner wrapping band layer of the cable group and the outer wrapping band layer of the cable group, the oppositely arranged monitoring capacitor plates are composed of a plurality of capacitor plate units which are longitudinally arranged, the oppositely arranged monitoring capacitor plates form a capacitive monitoring sensor element, when physical quantities such as the structural positions of conductors of the four-wire group and the cable group between the two monitoring capacitor plates, the cross section shapes of the conductors and the like are changed, the relative dielectric constant epsilon of the four-wire group and the cable group are also changed, the monitoring capacitor plates convert the changes into the changes of capacitance, and then the changes are converted into corresponding electric signals through a capacitance connecting wire and a conversion circuit to be output, so that the running state of each group of the four-wire group of the signal cable is monitored.

Because the lengths of the pole plates of the capacitor plate units longitudinally arranged along the cable are different, the position of the line group fault on the length of the cable can be accurately positioned according to the capacitance change rates corresponding to the pole plates with different lengths; any oppositely arranged initial capacitance C of monitoring capacitor plate₀=ε₀S/d (where ε₀The initial dielectric constant, S the area of the two polar plates covered with each other, and d the distance between the two polar plates; when physical quantities such as the line group and the line group conductor between the monitoring capacitor plates are changed, the dielectric constant is changed to epsilon₁And S/d is unchanged, the capacitance is C₁=ε₁S/d, the change rate of the position monitoring capacitance reflected by the monitoring capacitance plate is △ C/C₀=(C1-C₀)/C₀=(ε₁-ε₀)/ε₀Because the lengths of the polar plates of the capacitor plate units longitudinally arranged on the cable are different, the change rates of the initial capacitance and the monitoring capacitance of each capacitor plate unit are different, the position of a fault point of the cable group can be determined according to the difference of the change rates of the monitoring capacitance, and a maintenance scheme is formulated, so that the signal cable is well maintained to be in a safe and reliable running state all the time.

Still because each group shielding structure includes wired group shielding ripple area and supports in the group shielding ripple in-band line group shielding stay ring, the ripple shielding layer that adopts the embossing not only has comparatively stable shielding performance, can strengthen the crooked compliance of group and cable moreover, avoids the crooked extrusion deformation to insulating single line and insulated conductor when cable and group are crooked, can effectively guarantee the stability firm of insulating single line structure position. The annular shielding support ring embedded on the inner side of the shielding corrugated belt can effectively support and bear the pressure applied to the shielding wire group by external force, thereby forming a reliable protection structure, improving the anti-extrusion mechanical performance of the shielding four-wire group, not only ensuring the stability, coaxial capacitance, concentricity and roundness of the insulating single-wire structure in the shielding layer, but also avoiding the phenomena of crushing or breaking of the insulating layer and the conductor, and forming the dual effects of shielding and protection.

The total shielding structure also adopts the structure of the total shielding corrugated belt and the shielding support ring, and the total shielding corrugated belt and the shielding support ring replace the aluminum sleeve shielding structure in the existing signal cable, so that the weight and the overall dimension of the signal cable are greatly reduced, the signal cable has better laying flexibility, a firm and stable protection structure can be formed, the structural stability of each four-line group in the cable core is kept, and the mechanical properties of the signal cable, such as compression resistance, impact resistance and the like, are also kept.

The armor structure of signal cable adopts two layers to wrap around the package steel band structure, and it has the rubber sealing tape to inlay between the mutual overlap joint section of wrapping the package steel band and outer package steel band around the inlayer, the overlap joint structure of zero leakage has been formed, thereby make winding armor steel band form inclosed tubulose space, both had reinforcing tensile, compressive strength, improve cable interference killing feature, have high leakproofness again, moisture has been avoided completely along the radial infiltration and the invasion to the cable inside of cable, reliable tight waterproof performance has.

The insulating layer of the insulating single lines adopts a three-layer structure of a solid inner skin layer, a middle foam layer and a solid outer skin layer, so that the working capacitance between the insulating single lines is greatly reduced, and the attenuation constant of the transmission of the line set is reduced.

In a further embodiment of the present invention, the lengths of the adjacent capacitor plate units are increased or decreased by multiple times along the longitudinal direction, and the lengths of the oppositely arranged capacitor plate units are equal. The structure is convenient for distinguishing different capacitance change rates, thereby being accurately positioned.

In a preferred embodiment of the present invention, the longest capacitor plate unit of the capacitor plate units is located at the middle position in the longitudinal direction of the star quad, the lengths of the capacitor plate units from the longest capacitor plate unit to the two ends in the longitudinal direction of the star quad decrease by multiple, and the capacitor plate units arranged from the middle to the two ends of the star quad are connected in parallel by corresponding capacitor connecting lines, respectively, the spread angle of the capacitor plate units is α =100 °.

In a preferred embodiment of the present invention, the wire group shielding corrugated strip is an embossed copper strip, and the wire group shielding support ring is embedded in a corresponding corrugated groove of the wire group shielding corrugated strip. The wire group shielding support ring is made of carbon fibers, the wire group shielding support ring is composed of a shielding upper support ring and a shielding lower support ring, and the shielding upper support ring and the shielding lower support ring are mutually inserted and connected through a support ring tenon and a support ring groove. The structure is reasonable, the manufacture and the assembly are convenient, and the bearing capacity of the support ring can be effectively enhanced.

In a preferred embodiment of the present invention, the total shielding corrugated strip is an embossed copper strip, and the shielding support ring is embedded in a corresponding corrugated groove of the total shielding corrugated strip. The shielding support ring is made of carbon fiber, the shielding support ring is composed of an upper support ring and a lower support ring, and the upper support ring and the lower support ring are mutually inserted through an inserting tenon and an inserting groove. The structure is reasonable, the manufacture and the assembly are convenient, and the bearing capacity of the support ring is strong.

In a further embodiment of the present invention, the inner layer lapped steel strip is spirally and alternately lapped on the inner cushion layer; the outer layer wrapping steel belt is spirally and alternately wrapped on the inner layer wrapping steel belt. The distance between two adjacent sides of the inner-layer lapped steel belt or the outer-layer lapped steel belt spirally lapped is smaller than half of the width of the steel belt. The mechanical strength of the cable is effectively enhanced, and the anti-corrosion capability and the water resistance of the cable are improved.

Drawings

The railway digital signal cable of the invention is further explained by combining the attached drawings and the detailed description.

FIG. 1 is a schematic cross-sectional view of one embodiment of a railway digital signal cable according to the present invention;

FIG. 2 is a schematic cross-sectional view of the overall shielding structure of the railway digital signal cable shown in FIG. 1;

FIG. 3 is a schematic cross-sectional view of the upper support ring of the overall shield structure of FIG. 2;

FIG. 4 is a schematic left side view of the structure of FIG. 3;

FIG. 5 is a schematic cross-sectional view of the under-rounding of the overall shield structure of FIG. 2;

FIG. 6 is a schematic left side view of the structure of FIG. 5;

FIG. 7 is a schematic cross-sectional view of the armor layer of the railway digital signal cable shown in FIG. 1;

FIG. 8 is a schematic cross-sectional view of the insulated single-wire and star quad configuration of the railway digital signal cable shown in FIG. 1;

FIG. 9 is a schematic diagram of the structure of the monitoring capacitor in the quad star cell shown in FIG. 8;

FIG. 10 is a schematic cross-sectional view of a pair of monitoring capacitor plate cells oppositely disposed in the quad-bank cell of FIG. 8;

fig. 11 is a schematic cross-sectional view of the wire group shield structure in the railway digital signal cable shown in fig. 1;

FIG. 12 is a cross-sectional view of the wire-group shield support ring in the structure of FIG. 11;

FIG. 13 is a schematic cross-sectional view of the upper shield support ring of the structure of FIG. 12;

FIG. 14 is a left side view of the structure shown in FIG. 13;

FIG. 15 is a cross-sectional view of the shield lower support ring in the configuration of FIG. 12;

fig. 16 is a left side view of the structure shown in fig. 15.

In the figure, 1-outer sheath, 2-armor layer, 21-inner layer wrapped steel belt, 22-outer layer wrapped steel belt, 23-rubber sealing belt, 3-inner cushion layer, 4-total shielding layer, 41-total shielding corrugated belt, 42-shielding supporting ring, 43-upper supporting ring, 44-inserting tenon, 45-lower supporting ring, 46-inserting groove, 5-inner sheath, 6-wrapping belt layer, 7-insulating single wire, 71-conductor, 72-solid inner sheath layer, 73-middle foam layer, 74-solid outer sheath layer, 8-star quad group, 81-inner wrapping belt layer, 82-monitoring capacitor assembly, 821-monitoring capacitor plate, 822-capacitor connecting wire, 823-capacitor plate unit, 83-outer wrapping belt layer, 84-wire group shielding structure and 85-outer sheath wire group.

Detailed Description

As shown in fig. 1, the cable core of the digital railway signal cable is formed by twisting four star quad groups 8, but the number of star quad groups of the cable core is not limited to four, but there is at least one star quad group. Besides the star quad, the cable core may also include a pair of quad or/and an insulated single wire, and the number or color of the star quad and the pair of quad of the cable core is generally determined according to design requirements and according to the railway signal cable standard of the railway industry. The cable core is coated with a belting layer 6, an inner sheath 5, a total shielding structure 4, an inner cushion layer 3, an armor layer 2 and an outer sheath 1 from inside to outside in sequence. The belting layer 6 is formed by lapping one layer of insulating tape with the thickness of 0.05mm and two layers of insulating tape with the thickness of 0.2 mm; the inner sheath 5 is a polyethylene sheath extruded with the thickness of 1 mm; the inner cushion layer 3 is a polyethylene sleeve with the thickness of 1.3mm in an extrusion wrapping manner, and the outer sheath 1 is a low-smoke halogen-free flame-retardant sheath with the thickness of 2.1 mm.

As shown in fig. 2, the total shielding structure 4 includes a total shielding corrugated strip 41, the total shielding corrugated strip 41 is a conventional corrugated copper strip, and annular shielding support rings 42 are supported on an inner wall surface of the total shielding corrugated strip 41 at intervals. The bearing strength of the shielding structure can be changed by adjusting the spacing distance between two adjacent shielding support rings 42, so that the shielding structure is suitable for different use environments. The shield stay 42 is just fitted into the corresponding corrugated groove of the total shield corrugated strip 41, so that the shield stay 42 is relatively stably fixed to the inner wall surface of the total shield corrugated strip 41. The annular shield stay 42 is made of a carbon fiber material, and has the characteristics of light weight and high strength. The shield stay 42 is composed of an upper stay 43 and a lower stay 45.

As shown in fig. 3 and 4, the upper supporting ring 43 is a semicircular ring, and both ends of the semicircular ring are trapezoidal inserting tenons 44. As shown in fig. 5 and 6, the lower supporting ring 45 is also a semi-circular ring, two ends of the semi-circular ring are respectively provided with an inserting groove 46 with an inward concave trapezoidal cross section, and the cross sections of the inserting tenon 44 and the inserting groove 46 are matched so as to be mutually inserted into the shielding supporting ring 42 with an integral ring structure.

As shown in fig. 7, the armor layer 2 adopts a double-layer steel tape wrapping structure, and the armor layer 2 comprises an inner wrapping steel tape 21 and an outer wrapping steel tape 22 which are wrapped. The inner layer is spirally wound on the inner cushion layer 3 at intervals, and the outer layer is also spirally wound on the inner layer by the winding steel belt 21 at intervals, wherein the outer layer is wound on the outer layer by the winding steel belt 22. The spacing distance between two adjacent sides of the inner layer wrapping steel strip 21 or the outer layer wrapping steel strip 22 which are spirally wrapped should be less than or equal to half of the width of the steel strip, in this embodiment, the width of the steel strip of the inner layer wrapping steel strip 21 or the outer layer wrapping steel strip 22 is B, the spacing distance between two adjacent sides of the same steel strip is B, B =0.45B, preferably B = (0.40-0.50) B, but the spacing distance should be less than half of the width of the steel strip. Corresponding embedded grooves are formed between the mutually overlapped sections of the inner-layer wrapped steel belt 21 and the outer-layer wrapped steel belt 22, and rubber sealing belts 23 are embedded in the embedded grooves, so that the rubber sealing belts 23 are also spirally embedded between the overlapped sections of the inner-layer wrapped steel belt 21 and the outer-layer wrapped steel belt 22, and a tight water-blocking and waterproof structure is formed.

As shown in figure 8, the star quad 8 in the cable core is formed by twisting four insulated single wires 7, the conductor 71 of each insulated single wire is a metal copper wire with the diameter of 0.995mm, the conductor 1 is coated with an insulating layer, the outer diameter of the insulating layer is 2.75mm, the insulating layer is formed by a three-layer structure, and the three-layer structure comprises a solid inner skin layer 72, a middle foam layer 73 and a solid outer skin layer 74 from the conductor 1 to the outside in sequence. The four mutually-twisted insulated single wires 7 are sequentially wrapped with a wire group inner wrapping tape layer 81, a wire group outer wrapping tape 83, a wire group shielding structure 84 and a wire group outer sheath 85 from inside to outside, the wire group inner wrapping tape layer 81 is formed by wrapping an insulating tape with the thickness of 0.05mm, the wire group outer wrapping tape layer 83 is also formed by wrapping an insulating tape with the thickness of 0.05mm, and the wire group outer sheath 85 is formed by extruding polyethylene materials. Between the intraconnection tape layer 81 and the intraconnection tape layer 83, there are provided monitoring capacitor plate assemblies 82, and the monitoring capacitor plate assemblies 82 are symmetrically arranged on both sides of the axis of the starquad 7, thereby constituting a monitoring capacitive sensor.

As shown in fig. 9, the monitoring capacitor plates 821 on both sides of the axis of the star quad are all composed of a plurality of capacitor plate units 823 arranged along the length direction of the axis, and the lengths of each unit plate of each capacitor plate unit 823 are different. In this embodiment, since the length of the cable is long, the longest capacitor plate unit 823 is located at both sides of the middle position of the length of the cable, and the lengths of the cell plates of the capacitor plate units 823 at both ends of the star quad are decreased by multiple from the longest capacitor plate unit 823 to each other, for example, the longest capacitor plate unit 823 is L, the lengths of the capacitor plate units 823 at both ends are 1/2L, 1/4L, 1/8L, 1/16L, and … … in this order, thus the rate of change of capacitance of each capacitive plate cell 823 due to a failure is different, and the numerical value difference is large, so that the fault position can be accurately judged, and the capacitor plate units 823 from the longest capacitor plate unit 823 in the middle are connected in parallel with the corresponding capacitor connecting lines 822 respectively at the two ends, so that the two capacitor connecting lines 822 respectively correspond to the star-shaped four-wire group from the middle to the ends. Of course, the plate length of capacitor plate 823 may be increased by multiple continuously from one end to the other end, such as L, 2L, 4L, 8L, and … … from one end to the other end of the star quad. The capacitor plate units 823 on the same side are connected in parallel with each other through the capacitor connecting line 822, and the overhanging end of the capacitor connecting line 822 is connected to the monitoring conversion circuit, so as to be converted into corresponding electric signals.

As shown in fig. 10, the corresponding capacitor plate units 823 on both sides of the axis of the radial quad 8 are symmetrical arc-shaped plate units, the capacitor plate units 823 are thin copper sheets, the spread angle α =100 ° of the capacitor plate units 823, and the spread angle α of the capacitor plate units 823 should be controlled preferably to be α =90 ° -120 °.

As shown in fig. 11 and 12, the wire group shielding structure 84 includes a wire group shielding corrugated strip 841, the wire group shielding corrugated strip 841 uses a common corrugated copper strip, and annular wire group shielding support rings 842 are supported on the inner wall surface of the wire group shielding corrugated strip 841 at intervals. The bearing strength of the shielding structure can be changed by adjusting the spacing distance between the adjacent two wire group shielding support rings 842, so that the shielding structure is suitable for different use environments. The group shield stay 842 is just embedded in the corrugated groove corresponding to the group shield corrugated belt 841, so that the group shield stay 842 is stably fixed on the inner wall surface of the group shield corrugated belt 841. The annular wire group shielding support ring 842 is made of carbon fiber material, and has the characteristics of light weight and high strength.

As shown in fig. 12, the wire group shielding stay 842 is composed of a shielding upper stay 843 and a shielding lower stay 845. As shown in fig. 13 and 14, the shield upper stay 843 is a semicircular ring, and both ends of the semicircular ring are trapezoidal stay tenons 844. As shown in fig. 15 and 16, the shielding lower supporting ring 845 is also a semicircular ring, two ends of the semicircular ring are respectively provided with a supporting ring groove 846 with an inward concave trapezoidal cross section, and the cross section shapes of the supporting ring tenon 844 and the supporting ring groove 846 are matched so as to be mutually inserted into the wire group shielding supporting ring 8 with a whole ring structure.

The above description is only for the purpose of illustrating a preferred embodiment of the present invention, but the present invention is not limited to the embodiment, and many modifications and changes may be made without departing from the basic principle of the present invention, and these modifications and changes fall into the protection scope of the present invention.