A method for facilitating internal welding and sealing of leaky coaxial cable joints for high voltage power transmission tunnels and a welding method

Abstract

The application discloses a kind of for high-voltage transmission tunnel, facilitate internal welding and sealing leak coaxial cable joint and welding method, cable joint includes first joint rear body (1), second joint main body (2) and third joint main body (3);Welding method steps are: 1) leak coaxial cable is worn into cable joint;2) power supply is provided for heating body (4), so that heating body (4) completes leak coaxial cable and the welding of coaxial cable joint;3) by welding processing hole, sealing material is injected into cable joint inside;4) matching screw is screwed into welding processing hole, and cable joint is sealed.The application can improve leak coaxial cable and the connection firmness of feeder and connector, corrosion resistance, waterproof and moisture-proof degree.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cable, in particular to a coaxial cable joint for high-voltage power transmission tunnel and a welding method. BACKGROUND

[0002] In recent years, the pulse-related technology has been developing, and many high-power pulse technology-related applications have been popularized, including electromagnetic pulse, which is a promising technology. Compared with traditional welding technology, this technology is a solid-phase welding technology that can be used for welding dissimilar metals and metals and non-metals. The welding speed can reach the level of microseconds, the discharge energy of the welding process can be accurately controlled, the repeatability is good, the automation and mechanization level is high, and the welding process is environmentally friendly and pollution-free, so it has a broad application and promotion prospect. At present, scholars at home and abroad have carried out research on this technology, and have carried out electromagnetic pulse welding tests on aluminum alloy of the same kind and dissimilar metals. The results show that the strength of the metal joint of electromagnetic pulse welding almost does not decrease, and the mechanism of electromagnetic pulse welding is proposed. By using the electromagnetic pulse welding method, dissimilar material welding test of pure copper and anti-rust aluminum can obtain high-quality welded joints.

[0003] Leaky coaxial cable is a waveguide device that uses the slots on the outer conductor of the coaxial cable to radiate electromagnetic waves outward and communicate wirelessly with the outside space. It is applied to wireless communication in enclosed spaces such as mines and tunnels. With the vigorous development of mobile communication, it is also applied to mobile communication along the subway, high-speed railway, and high-rise buildings. Leaky coaxial cable is artificially opened with a series of slots on the outer conductor of the coaxial cable, which has the functions of transmission line and continuous antenna. Each slot along the axial direction of the coaxial cable is an electromagnetic wave radiation source, and the electromagnetic field radiated by all the slots along the axial direction is superimposed to form the radiation field around the cable. Theoretical analysis of the radiation field of leaky coaxial cable is very complex. Currently, the original overhead power transmission lines in cities are gradually replaced by power cables. With the increase of cable tunnels, new challenges are posed for the daily operation and emergency repair of cable tunnels. During the operation and repair of the tunnel, how to ensure effective communication between the tunnel staff and the outside world is one of the key factors to ensure the safety of the tunnel staff.

[0004] In the installation of leaky coaxial cable and joint, the inner conductor copper core of the coaxial cable is directly inserted into the corresponding hole of the joint, and no other measures are taken to increase the connection reliability. Because the leaky coaxial cable is usually thick in diameter and the cable body is heavy, it is installed in a tunnel with high humidity. During use, the coaxial cable joint may be deformed, displaced, or corroded, making the leaky coaxial cable unable to work normally. SUMMARY

[0005] The utility model provides a kind of for high-voltage transmission tunnel's inside welding and sealing leak coaxial cable joint easily, including joint rear body, cable compression ring and joint front body;

[0006] The joint rear body and joint front body are screwed, to form a cavity;

[0007] The cable compression ring is installed in the cavity, and is tightly clamped on the outer conductor surface of leak cable;

[0008] The side wall of the cable compression ring is provided with a plurality of welding processing holes;

[0009] The welding processing hole is used for injecting sealing material.

[0010] A welding method for a leak coaxial cable joint for high-voltage transmission tunnel easily welded and sealed, comprising the following steps:

[0011] 1) pass the leak coaxial cable into the cable joint;

[0012] 2) complete the welding of the leak coaxial cable and the coaxial cable joint using a welding heating device;

[0013] 3) inject sealing material into the cable joint through the welding processing hole;

[0014] 4) screw matching screws into the welding processing hole to seal the cable joint.

[0015] The technical effect of the utility model is self-evident, and the beneficial effects of the utility model are as follows:

[0016] 1) the utility model can improve the connection firmness, corrosion resistance and waterproofness of the leak coaxial cable and the connection head.

[0017] 2) the utility model can improve the installation quality and efficiency of the leak coaxial cable and the connection head. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is the assembly drawing of leak cable joint;

[0019] Figure 2 is the component drawing of leak cable joint

[0020] Figure 3 is the thread processing hole mode

[0021] Figure 4 is the schematic view of leak cable joint;

[0022] Figure 5 is the basic circuit of electromagnetic pulse welding forming

[0023] Figure 6 Equivalent circuit of electromagnetic pulse welding forming;

[0024] In the figure: joint rear body 1, cable compression ring 2 and joint front body 3, welding heating device 4, connecting rod 5, chip 6, welding processing hole A. DETAILED DESCRIPTION

[0025] The application will be further described below in conjunction with the examples, but should not be understood as limiting the above-mentioned subject matter of the application to the following examples. Various substitutions and modifications can be made according to ordinary technical knowledge and conventional means in the art without departing from the above-mentioned technical idea of the application, and all of them should be included in the protection scope of the application.

[0026] Example 1:

[0027] Reference Figures 1 to 6 A joint for high-voltage transmission tunnel for facilitating internal welding and sealing of a leaking coaxial cable, comprising a joint rear body 1, a cable compression ring 2 and a joint front body 3.

[0028] The joint rear body 1 and the joint front body 3 are threadedly connected to form a cavity;

[0029] The cable compression ring 2 is installed in the cavity and tightly clamps the outer conductor surface of the leaking cable;

[0030] The side wall of the cable compression ring 2 is provided with a plurality of welding processing holes;

[0031] The welding processing holes are used for injecting sealing material.

[0032] A welding method for a joint for high-voltage transmission tunnel for facilitating internal welding and sealing of a leaking coaxial cable, comprising the following steps:

[0033] 1) Insert the leaking coaxial cable into the cable joint;

[0034] 2) Use the welding heating device 4 to complete the welding of the leaking coaxial cable and the coaxial cable joint, and the specific process is that the chip 6 controls the welding heating device 4 to weld through the connecting rod 5;

[0035] 3) Inject sealing material into the cable joint through the welding processing hole;

[0036] 4) Screw the matching screw into the welding processing hole A to seal the cable joint.

[0037] Example 2:

[0038] A joint for high-voltage transmission tunnel for facilitating internal welding and sealing of a leaking coaxial cable, the contents include:

[0039] Leakage coaxial cable has signal transmission function and antenna function. Through the control of the opening of the outer conductor, the controlled electromagnetic wave energy can be uniformly radiated along the line and received, the coverage of electromagnetic field blind area is realized, and the purpose of smooth mobile communication is achieved. Leakage coaxial cable is formed by periodically or non-periodically arranging narrow slots on the outer conductor of the coaxial cable according to specific electromagnetic field theory. Each slot distributed along the axis of the coaxial cable is an electromagnetic wave radiation source. While the electric signal is transmitted in the cable, part of the electromagnetic energy can be uniformly radiated to the surrounding space in the form of electromagnetic wave from the slot according to the requirement.

[0040] At present, the frequency band of leakage cable covers 450MHz-2GHz or above, which is suitable for existing wireless communication system. The application scenarios include various spaces with limited wireless propagation.

[0041] Compared with the traditional antenna system, the leakage cable system has the following advantages:

[0042] 1. Uniform signal coverage, especially suitable for narrow spaces such as tunnels;

[0043] 2. Leakage cable is essentially a wideband system. Some models of leakage cable can be used in CDMA800, GSM900, GSM1800, WCDMA and WLAN systems at the same time;

[0044] 3. The insulation medium of leakage cable adopts a uniform and fine closed micro-bubble structure by physical foaming. Compared with the traditional air insulation structure, the transmission parameters such as characteristic impedance, standing wave ratio and attenuation are more uniform and stable. Moreover, it can resist the invasion of moisture in the wet environment, which can cause the decline or loss of transmission performance, greatly improving the service life and stability and reliability of the product.

[0045] 4. Wide frequency, uniform and stable field strength radiation, high pressure resistance and high tensile strength, no special requirements for construction.

[0046] 5. Although the price of leakage cable is higher, it is reliable in work, long in service life, simple in maintenance and low in comprehensive cost.

[0047] Combined with the advantages of repeater and leakage cable, full coverage of mobile phone signal can be realized in any curved tunnel.

[0048] The basic circuit of electromagnetic pulse welding forming is as follows: Figure 5As shown, it is approximately a pulse current source. Its working principle mainly includes: ① charging process: open the TVS (Triggered Vacuum Swtich), close the vacuum relay, control the high-voltage DC power supply to charge the pulse capacitor; ② discharging process: first open the vacuum relay, control the trigger signal to make the TVS conduct, the capacitor discharges through the loop to the welding coil, the whole loop is approximately short-circuit discharge, and its equivalent circuit is as shown in Figure 6 Due to the inductance and resistance existing in the welding coil itself and the circuit, the loop is an RLC oscillation, and even a small inductance and resistance will affect the oscillation period and the rising edge of the pulse current, affect the size of the induced magnetic field, and thus make the welding effect worse. Therefore, the influence of the resistance and inductance in the loop needs to be fully considered, and a suitable circuit structure needs to be designed.

[0049] Let the discharge voltage be U, and the current of the discharge loop be I(t), according to the Kirchhoff voltage law

[0050]

[0051] Taking the derivative of I(t) with respect to t can obtain

[0052]

[0053] In the formula, C is the pulse capacitor; L is the inductance of the whole loop; and R is the resistance of the whole loop. According to the second derivative solving formula and the initial condition of the circuit, it is obtained that

[0054] I(t)| t＝0 = 0 (3)

[0055]

[0056] Then

[0057]

[0058]

[0059] In the formula, ω is the inherent frequency of the loop. As known from formula (5), the peak value of the current is related to the charging voltage, the loop resistance and the loop inductance. Taking the derivative of formula (5) obtains

[0060]

[0061] According to formula (5) and formula (7), the first current peak value I reached by the RLC oscillation can be obtained max And the time t is

[0062]

[0063]

[0064] According to the law of electromagnetic induction, the size of the induced magnetic field is related to the current, and the magnetic induction strength B is proportional to the current, that is,

[0065] B∝I(t) (10)

[0066] Therefore, the size of the induced magnetic field is related to the resistance and inductance in the loop. As can be seen from equation (8), the smaller the inductance of the loop, the greater the peak current, and the greater the magnetic induction strength. Therefore, appropriate measures should be taken to reduce the inductance of the loop as much as possible.

[0067] The application designs a joint with holes on the side, which can effectively improve the connection firmness of the leaked coaxial cable and the connection head by reserving welding processing holes at appropriate positions of the cable joint, thread processing the hole wall, injecting sealing materials from the processing holes after welding, and finally screwing matching screws into the processing holes for sealing.

[0068] The application reserves welding processing holes at appropriate positions of the cable joint, thread processes the hole wall, injects sealing materials from the processing holes after welding, and finally screws matching screws into the processing holes for sealing.

[0069] Example 3:

[0070] A leaked coaxial cable joint for high-voltage power transmission tunnels is convenient for internal welding and sealing, which comprises a joint rear body 1, a cable compression ring 2 and a joint front body 3.

[0071] The joint rear body 1 and the joint front body 3 are threadedly connected to form a cavity.

[0072] The cable compression ring 2 is installed in the cavity and tightly clamps the outer conductor surface of the leaked cable;

[0073] A plurality of welding processing holes are formed in the side wall of the cable compression ring 2.

[0074] The welding processing holes are used for injecting sealing materials.

[0075] Example 4:

[0076] A welding method for a leaked coaxial cable joint for high-voltage power transmission tunnels is convenient for internal welding and sealing, which comprises the following steps:

[0077] 1) The leaked coaxial cable is inserted into the cable joint;

[0078] 2) The welding of the leaked coaxial cable and the coaxial cable joint is completed by using a welding heating device;

[0079] 3) Sealing materials are injected into the cable joint through the welding processing holes.

[0080] 4) Screw matching screw into the welding processing hole to seal the cable joint.

Claims

1. A soldering method for facilitating internal soldering and sealing of leaky coaxial cable joints using for high voltage power transmission tunnels, characterized by, The welding method is used for facilitating internal welding and sealing of a leaking coaxial cable joint; The method for facilitating internal welding and sealing of a leaking coaxial cable joint comprises a joint rear body (1), a cable compression ring (2) and a joint front body (3); The joint rear body (1) and the joint front body (3) are threadedly connected to form a cavity; The cable compression ring (2) is installed in the cavity and tightly clamps the outer conductor surface of the leaking cable; A plurality of welding processing holes are formed in the side wall of the cable compression ring (2); The welding processing holes are used for injecting sealing material; The welding method comprises the following steps: 1) inserting the leaking coaxial cable into the cable joint; 2) using a welding heating device to complete welding of the leaking coaxial cable and the coaxial cable joint; 3) injecting sealing material into the cable joint through the welding processing holes; 4) screwing a matching screw into the welding processing hole to seal the cable joint.

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