Variable frequency cable

Abstract

The frequency conversion cable comprises an optical cable used for detecting temperature and detecting on-off of signals, an outer sheath, and a frequency conversion wire arranged in the outer sheath and used for transmitting electric energy, and the optical cable is arranged between the outer sheath and the frequency conversion wire and is arranged close to the inner wall of the outer sheath. According to the utility model, the optical cable is arranged between the outer sheath and the frequency conversion lead, and the optical cable is arranged close to the inner wall of the outer sheath, so that the optical cable can quickly sense abnormal temperature rise of the frequency conversion lead and external temperature change outside the outer sheath. When the temperature is too high, the optical signal of the optical cable changes, so that the current in the variable-frequency lead can be controlled to be reduced or power supply can be cut off. Meanwhile, when the outer sheath, close to one side of the optical cable, of the variable-frequency cable is broken, the optical cable is arranged close to the inner wall of the outer sheath, so that the optical cable is broken prior to the variable-frequency wire. Therefore, when the optical cable is fractured but the variable-frequency lead is not fractured, it can be quickly known that the variable-frequency cable is about to be fractured, and maintenance of the variable-frequency cable is facilitated.

Description

Technical Field

[0001] This utility model relates to the field of cables, and more particularly to a frequency conversion cable. Background Technology

[0002] In recent years, with the transformation of the global energy structure and the rapid development of marine engineering, the shipbuilding industry has increasingly demanded energy conservation, emission reduction, and efficient operation. Variable frequency technology (VFD), as a highly efficient and energy-saving power control technology, has been widely used in ship power systems, and VFD cables, as an important component of ship power systems, are seeing a continuous increase in usage.

[0003] Variable frequency cables generate more heat than conventional cables. Variable frequency systems produce high-order harmonic currents, which cause more current to concentrate on the surface of the conductor. At the same time, additional inductive losses are generated between adjacent conductors, which further increases heat generation.

[0004] However, there is no simple component in the existing technology to monitor abnormal heating of frequency converter cables. If the abnormal heating of frequency converter cables is not controlled, the high temperature will accelerate the oxidation of the conductor surface, increase the contact resistance, further aggravate the heating, form a vicious cycle, and may eventually cause a fire. Utility Model Content

[0005] To address the problems existing in the prior art, this utility model discloses a frequency conversion cable that facilitates temperature detection.

[0006] The objective of this utility model is achieved through the following technical solution:

[0007] A frequency conversion cable includes an optical cable for detecting temperature and signal continuity, an outer sheath, and a frequency conversion conductor disposed within the outer sheath for transmitting electrical energy. The optical cable is disposed between the outer sheath and the frequency conversion conductor and is located close to the inner wall of the outer sheath.

[0008] Furthermore, a communication cable for transmitting data is also provided inside the outer sheath.

[0009] Furthermore, a ground wire core is also provided inside the outer sheath.

[0010] Furthermore, a steel wire rope is also provided inside the outer sheath.

[0011] Furthermore, the steel wire rope, the frequency converter conductor, the optical cable, the communication cable, and the ground wire core are twisted together; the frequency converter conductor has three wires arranged in a triangular pattern around the steel wire rope; two adjacent frequency converter conductors cooperate with the outer sheath to form a gap area, and the optical cable, the communication cable, and the ground wire core are each located in different gap areas.

[0012] Furthermore, the frequency conversion conductor comprises, from the inside out, a conductor, an aramid fiber reinforcing layer, and an insulation layer.

[0013] Furthermore, the conductor is formed by bundling and twisting several monofilaments, with the bundling direction of the monofilaments opposite to the twisting direction of the monofilaments, and the twisting direction of the monofilaments in adjacent layers being opposite.

[0014] Furthermore, the communication cable includes a communication line and a drain wire.

[0015] Furthermore, the outer sheath has a shielding layer on the side facing the optical cable, and the steel wire rope, the frequency conversion conductor, the optical cable, the communication cable, and the ground wire core are all located on the side of the shielding layer away from the outer sheath.

[0016] Furthermore, the shielding layer is provided with an aramid mica composite tape layer on the side away from the outer sheath, and the steel wire rope, the frequency conversion conductor, the optical cable, the communication cable and the ground wire core are all located on the side of the aramid mica composite tape layer away from the shielding layer.

[0017] Compared with existing technologies, the advantages of this invention are as follows: By placing the optical cable between the outer sheath and the frequency converter conductor, and positioning the optical cable close to the inner wall of the outer sheath, the optical cable can quickly sense abnormal temperature rises in the frequency converter conductor and changes in the external temperature outside the outer sheath. When the temperature is too high, the optical signal of the optical cable changes, thereby controlling and reducing the current in the frequency converter conductor or cutting off the power supply. Simultaneously, when the frequency converter cable is subjected to external force and the outer sheath near the optical cable breaks, the optical cable, being close to the inner wall of the outer sheath, will break before the frequency converter conductor. Therefore, when the optical cable breaks but the frequency converter conductor does not, it is quickly known that the frequency converter cable is about to break, facilitating the maintenance of the frequency converter cable. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of the frequency conversion cable of this utility model.

[0019] In the picture:

[0020] 1-Optical cable; 2-Outer sheath; 3-Ground core; 4-Steel wire rope; 5-Conductor; 6-Reinforcing layer; 7-Insulation layer; 8-Core wire; 9-Draining wire; 10-Aramid mica composite tape layer; 11-Main shielding tape; 12-Braided shielding layer. Detailed Implementation

[0021] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0022] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0024] This utility model discloses a frequency conversion cable, mainly used in ships. Figure 1 As shown, the variable frequency cable of this utility model includes an optical cable 1 for detecting temperature and signal continuity, an outer sheath 2, and a variable frequency conductor disposed within the outer sheath 2 for transmitting electrical energy. The optical cable 1 includes a cable core and a nitrile rubber layer wrapped around the cable core. During the manufacturing process of the optical cable 1, the optical cable 1 is subjected to low-temperature tank vulcanization, which makes the optical cable 1 less susceptible to damage and improves its flexibility.

[0025] In this invention, optical cable 1 is positioned between the outer sheath 2 and the frequency converter conductor, and is located close to the inner wall of the outer sheath 2. Optical cable 1 is a temperature-sensitive cable. Because optical cable 1 is close to both the frequency converter conductor and the outer sheath 2, it can quickly sense abnormal temperature increases in the frequency converter conductor and changes in the external temperature outside the outer sheath. The frequency converter cable of this invention is typically connected to a control system. When the frequency converter conductor and / or the external temperature are too high, the intensity of the scattered light from the optical fiber in optical cable 1 changes. Upon receiving this information, the control system can reduce the current in the frequency converter conductor or cut off the power supply, thereby lowering the operating temperature of the frequency converter cable and reducing the likelihood of a fire.

[0026] Meanwhile, in actual production, the diameter of optical cable 1 is usually smaller than that of the frequency converter conductor. Under the same shear force, optical cable 1 is more prone to breakage than the frequency converter conductor. When the frequency converter cable is about to break under external force, such as when it is subjected to shear force, the shear force acts on the outer sheath 2 near optical cable 1, causing the outer sheath 2 near optical cable 1 to crack. Because optical cable 1 is located close to the inner wall of the outer sheath, and the diameter of optical cable 1 is smaller than that of the frequency converter conductor, even if... Figure 1 As shown, the diameter of the frequency converter conductor is larger than that of the optical cable 1, so it is also located close to the inner wall of the outer sheath 2. Under the continued action of shear force, the optical cable 1 will also break before the frequency converter conductor. Therefore, when the optical cable 1 breaks but the frequency converter conductor does not break, it is possible to quickly know whether the frequency converter cable is about to break, which facilitates the maintenance of the frequency converter cable.

[0027] In the bone plate of this utility model, many technical features, such as the other structures within the outer sheath 2 and the structure of the frequency converter wire, have multiple implementations. Below, for each of these technical features, one implementation is selected for detailed description, and the embodiment in which this implementation is located is referred to as this embodiment. Other implementations of the other structures within the outer sheath 2 are referred to as other embodiments, which are briefly described below.

[0028] In this embodiment, as Figure 1 As shown, a communication cable for data transmission is also provided inside the outer sheath 2. The function of the communication cable is to transmit data signals, and optical signals are used for transmission. Therefore, the frequency conversion cable in this embodiment is essentially an optoelectronic composite cable, capable of transmitting both electrical energy and data. In other embodiments, a communication cable may not be provided.

[0029] In this embodiment, as Figure 1 As shown, a ground wire core 3 is also provided inside the outer sheath 2. The function of the ground wire core 3 is: since the frequency converter cable transmits a current with varying frequency, this current will generate electromagnetic radiation around the cable and also form induced stray currents inside the cable. The ground wire core 3 can conduct these stray currents and the induced currents generated by electromagnetic radiation, reducing the impact of these currents on the power signal transmitted by the frequency converter cable itself and ensuring the stability of power transmission. In other embodiments, the ground wire core 3 may not be provided.

[0030] In this embodiment, as Figure 1 As shown, a steel wire rope 4 is also provided inside the outer sheath 2, and the steel wire rope 4 is located at the center of the entire frequency conversion cable. The function of the steel wire rope 4 is to provide mechanical strength and tensile strength. In particular, when the frequency conversion cable of this invention is moved, the high strength of the steel wire rope 4 can withstand the weight of the cable itself, as well as the tensile force generated during laying and use, preventing the frequency conversion cable from being pulled apart. In other embodiments, the steel wire rope 4 may not be provided.

[0031] In this embodiment, as Figure 1 As shown, the steel wire rope 4, frequency converter conductor, optical cable 1, communication cable, and grounding core 3 are twisted together in a left-hand direction. Three frequency converter conductors are arranged in a triangular pattern around the steel wire rope 4. Adjacent frequency converter conductors cooperate with the outer sheath 2 to form a gap area. One optical cable 1, one communication cable, and one grounding core 3 are each located in different gap areas; that is, the optical cable 1, communication cable, and grounding core 3 are arranged in an inverted triangular pattern around the outside of the frequency converter conductor. In this invention, the structure inside the outer sheath 2 is equivalent to a structure with the steel wire rope 4 on the innermost side, the triangularly arranged frequency converter conductor in the middle, and the inverted triangularly arranged optical cable 1, communication cable, and grounding core 3 on the outer side. The optical cable 1, communication cable, and grounding core 3 have the same diameter, all smaller than the frequency converter conductor. Ideally, the frequency converter conductor, optical cable 1, communication cable, and grounding core 3 are all in contact with the outer sheath 2, giving the frequency converter conductor good structural stability. Meanwhile, the identical twisting direction among the steel wire rope 4, frequency converter conductor, optical cable 1, communication cable, and grounding core 3 reduces relative movement and friction among them, decreasing wear and extending the service life of the frequency converter cable. It also improves electromagnetic compatibility by reducing electromagnetic interference and radiation generated within the frequency converter cable. In other embodiments, a partition plate can be installed between the steel wire rope 4, frequency converter conductor, optical cable 1, communication cable, and grounding core 3.

[0032] In this embodiment, due to the need for the frequency converter cable to be used on a ship, the cable needs to move within the ship's cabin space. This means the cable needs good bending freedom to adapt to the complex layout and movement conditions inside the ship. Simultaneously, the ship experiences dynamic conditions such as swaying, vibration, and deformation during navigation. It is also necessary to ensure that the frequency converter cable is not prone to breakage under tension and torsion during movement, guaranteeing stable transmission and reliable operation. To meet this requirement, the frequency converter conductor is configured from the inside out as follows: conductor 5, aramid fiber reinforcement layer 6, and insulation layer 7. The conductor 5 transmits electrical energy. The aramid fiber reinforcement layer 6 is a layer of 3160D aramid fiber braided using a 36-spindle braiding machine on the outside of the conductor 5. The braiding pitch is the outer diameter of the conductor 5 × π, which balances mechanical strength and flexibility. The aramid fiber reinforcement layer 6 primarily enhances the tensile and torsional resistance of the conductor 5. The insulation layer 7 is made of ethylene propylene insulating material, manufactured through an insulation vulcanization process. The insulation processing temperature is 55-85℃, and the insulation vulcanization pressure is 1.2MPa-1.5MPa, ensuring thorough insulation vulcanization. Thorough vulcanization of the insulation layer 7 optimizes its mechanical properties and fatigue resistance. Besides the frequency converter conductor having the insulation layer 7, the grounding core 3 and the optical signal transmission cable in the communication cable are also wrapped with the same material as the insulation layer 7. This invention, through the inclusion of the aramid fiber reinforcement layer 6 and the insulation layer 7, gives the frequency converter cable strong tensile strength, allowing it to move within the ship. In other embodiments, where the frequency converter cable is fixed in place, only the insulation layer 7 needs to be installed on the conductor 5.

[0033] In this embodiment, as Figure 1 As shown, conductor 5 is formed by bundling and twisting several monofilaments. The bundling direction of the monofilaments is opposite to the twisting direction, and the twisting direction of adjacent layers of monofilaments is also opposite. Specifically, conductor 5 uses tin-plated Category 5 flexural tin-plated copper monofilaments to ensure that the monofilaments are not easily broken or punctured by the insulation layer 7 during dynamic operation of the frequency converter cable. The nominal diameter of the monofilaments is 0.25 to 0.40 mm, and each monofilament is twisted in a multi-strand (1+6+12+18) configuration. The strand bundling direction is left-handed, the first twisting direction is right-handed, and the second twisting direction (twisting of the outermost monofilament) is left-handed. Setting the strand bundling and twisting directions opposite helps to enhance the overall stability of conductor 5, helps conductor 5 maintain a more consistent structure and performance during bending and torsion, reduces uneven internal stress distribution caused by twisting direction, improves the overall fatigue resistance of conductor 5, effectively reduces fatigue damage during repeated bending and torsion, extends the service life of the conductor, and facilitates the movement of the frequency converter cable. Simultaneously, reducing internal friction decreases the mutual friction between individual filaments when the frequency converter cable is bent and twisted, thereby reducing wear and heat generation. In other embodiments, the twisting direction of each filament may also be the same.

[0034] Meanwhile, since the outermost strand of conductor 5 is twisted to the left, and the three frequency converter wires are also twisted to the left, this helps maintain the structural stability of the frequency converter cable. The frequency converter cable is less prone to structural deformation under bending and tensile conditions.

[0035] In this embodiment, as Figure 1 As shown, the communication cable includes a communication line 8 and a guide wire 9. The communication line 8 is responsible for transmitting optical signals and is wrapped with ethylene propylene insulation material. Two communication lines 8 are provided, cabled from left to right. Each communication line 8 is wrapped with an overlapping layer of copper-plastic / aluminum-plastic composite tape. The guide wire 9 is also wrapped with the copper-plastic / aluminum-plastic composite tape, serving as a shield to prevent external interference to the communication line 8. An additional layer of non-metallic tape is wrapped outside the copper-plastic / aluminum-plastic composite tape. In other embodiments, the guide wire 9 may be omitted.

[0036] In this embodiment, as Figure 1 As shown, the outer sheath 2 has a shielding layer on the side facing the optical cable 1. The steel wire rope 4, frequency converter wire, optical cable 1, communication cable, and ground wire core 3 are twisted together to form a stranded cable core, which is located on the side of the shielding layer away from the outer sheath 2. That is, the shielding layer is equivalent to an inner tube inside the outer sheath 2, and the stranded cable core is located inside the tubular shielding layer. From the stranded cable core towards the outer sheath 2, the shielding layer consists of a main shielding strip 11 and a braided shielding layer 12. The main shielding strip 11 is composed of a layer of copper-plastic composite tape or aluminum-plastic composite tape overlapped and wound, with the metal side facing the braided shielding layer 12, forming electrical contact with it, with an overlap rate of 25%-35%. The braided shielding layer 12 is woven from metal composite aramid fibers, which are tin-plated copper annealed, flattened, and wound onto 400D aramid fibers. This invention, through the installation of a shielding layer, not only achieves shielding (suppressing electromagnetic interference during inverter operation) but also enhances the tensile strength of the inverter cable, reduces the probability of the single filament in conductor 5 breaking during operation, and improves the service life of the inverter cable. In other embodiments, the shielding layer may simply consist of shielding material spirally wound around the stranded cable core.

[0037] In this implementation, such as Figure 1 As shown, the outer sheath 2 is made of low-smoke halogen-free rubber sheath material, and the thickness of the outer sheath 2 is not less than 1 mm. The tear strength of the low-smoke halogen-free rubber sheath material is greater than or equal to 10 N / mm, and the original mechanical properties are greater than or equal to 15 MPa. This ensures that the outer sheath 2 has excellent strength while reducing the probability of broken wires in the shielding layer puncturing the outer sheath 2 and causing frequency converter cable failure. In other embodiments, the outer sheath 2 can also be made of neoprene rubber.

[0038] In this embodiment, as Figure 1As shown, an aramid-mica composite tape layer 10 is provided on the side of the shielding layer away from the outer sheath 2. The steel wire rope 4, frequency converter wire, optical cable 1, communication cable, and ground wire core 3 are all located on the side of the aramid-mica composite tape layer 10 away from the shielding layer, that is, the aramid-mica composite tape layer 10 is located inside the shielding layer, and the aramid-mica composite tape layer 10 wraps around the stranded cable core. In detail, the aramid-mica composite tape layer 10 is an aramid-mica composite tape wrapped around the stranded cable core. The aramid-mica composite tape has an overlap rate of 25-30% and a wrapping direction to the right. The aramid-mica composite tape is composed of aramid fiber, mica sheet, and polyimide substrate. The tensile strength of the aramid-mica composite tape is more than three times that of traditional wrapping tape, and it can withstand high temperatures of 260℃. It effectively enhances the tightness of the stranded cable core and reduces the probability of the wrapping tape breaking during the twisting process of the stranded cable core and the insulation layer 7 in the stranded cable core being punctured by the shielding layer. In other embodiments, such as when the frequency conversion cable is fixed on the ship and does not move, the aramid mica composite tape layer 10 may not be provided.

[0039] In summary, the frequency conversion cable of this invention, by placing the optical cable 1 between the outer sheath 2 and the frequency conversion conductor, and positioning the optical cable 1 close to the inner wall of the outer sheath 2, can detect the temperature of the frequency conversion conductor and the outside of the frequency conversion cable, thus preventing the frequency conversion cable from operating at excessively high temperatures. Furthermore, when the outer sheath near the optical cable 1 is damaged or cracked, it can quickly detect whether the frequency conversion cable is about to break. The inclusion of a communication cable makes this frequency conversion cable a photoelectric composite cable. The ground core 3 serves to conduct induced current. The steel wire rope 4 provides mechanical strength and tensile strength to the frequency conversion cable. The structure, with the steel wire rope 4 on the innermost side, the frequency conversion conductor arranged in a triangular pattern in the middle, and the optical cable 1, communication cable, and ground core 3 arranged in an inverted triangular pattern on the outer side, gives the frequency conversion conductor good structural stability. The inclusion of the aramid fiber reinforcement layer 6 and the insulation layer 7 gives the frequency conversion cable strong tensile strength. By setting the strands of each conductor to be twisted in opposite directions, the overall stability of conductor 5 is enhanced. The guide wires 9 provide shielding. The shielding layer not only provides shielding but also increases the tensile strength of the frequency converter cable. The aramid-mica composite tape layer 10 reduces the probability of the insulation layer 7 being punctured by the shielding layer.

[0040] It should be emphasized that the above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. A frequency varying cable, characterized by, The cable (1) for detecting temperature and detecting on-off signal, the outer sheath (2), the variable frequency wire for transmitting electric energy arranged in the outer sheath (2), the optical cable (1) is arranged between the outer sheath (2) and the variable frequency wire and is arranged close to the inner wall of the outer sheath (2).

2. The variable frequency cable of claim 1, wherein, The outer sheath (2) is further provided with a communication cable for transmitting data.

3. The variable frequency cable of claim 2, wherein, The outer sheath (2) is further provided with a ground wire core (3).

4. The variable frequency cable of claim 3, wherein, The outer sheath (2) is further provided with a steel wire rope (4).

5. The variable frequency cable of claim 4, wherein, The steel wire rope (4), the variable frequency wire, the optical cable (1), the communication cable, the ground wire core (3) are twisted into shape; the variable frequency wire is provided with three and is arranged in a triangular shape around the steel wire rope (4); two adjacent variable frequency wires and the outer sheath (2) cooperate to form a gap region, and the optical cable (1), the communication cable and the ground wire core (3) are respectively located in different gap regions.

6. The variable frequency cable of claim 5, wherein, The variable frequency wire comprises, from inside to outside, a conductor (5), an aramid fiber reinforcing layer (6) and an insulating layer (7).

7. The variable frequency cable of claim 6, wherein, The conductor (5) is formed by twisting a plurality of single filaments, and the twisting direction of the single filaments is opposite to the twisting direction of the single filaments.

8. The variable frequency cable of claim 2, wherein, The communication cable comprises a communication wire (8) and a drainage wire (9).

9. The variable frequency cable of claim 6, wherein, The outer sheath (2) is provided with a shielding layer on the side facing the optical cable (1), and the steel wire rope (4), the variable frequency wire, the optical cable (1), the communication cable and the ground wire core (3) are all arranged on the side of the shielding layer away from the outer sheath (2).

10. The variable frequency cable of claim 9, wherein, The shielding layer is provided with an aramid mica composite tape layer (10) on the side away from the outer sheath (2), and the steel wire rope (4), the variable frequency wire, the optical cable (1), the communication cable and the ground wire core (3) are all arranged on the side of the aramid mica composite tape layer (10) away from the shielding layer.

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