Power transmission line lead ground potential wiring board-free lap joint method based on electric contact constant voltage control

Abstract

The invention provides a power transmission line lead ground potential wiring board-free lap joint method based on electric contact constant voltage control, which is suitable for a 66KV power transmission line ground potential connection operation scene, and comprises the following specific steps: removing dirt outside a lead and loosening an oxide layer, ensuring that the surface of a conductor is clean, and meeting the basic condition of subsequent reliable contact; required constant-voltage contact force is calculated, and it is ensured that long-term electrical stability and anti-vibration performance meet operation specifications after lap joint; an electric positioning mode is adopted to complete accurate fixation of a lead lap joint section, and a potential coupling structure is introduced, so that continuous conduction of ground potential is ensured, and the problems of electric corrosion and the like caused by poor contact or potential suspension are avoided; when the wire is inserted, the wedge block is compressed, and the wire is reversely tightened under the action of elastic force after being positioned, thereby realizing self-locking fixation of the wire. Ground potential lead lap joint under the condition of no wiring board is achieved, the contact reliability, the electrical stability and the high-altitude operation efficiency are remarkably improved, and good engineering adaptability and popularization value are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power transmission construction, and particularly relates to a ground potential no-connection-plate lapping method for a transmission line lead wire based on electric contact constant voltage control. BACKGROUND

[0002] In the operation and maintenance process of the power system, the transmission line as the core channel of high-voltage power transmission, its construction quality and electrical connection reliability are directly related to the stable operation of the entire power grid. In particular, in the construction and reconstruction of the 66-kilovolt voltage level transmission line, in order to protect the safety of the operating personnel and realize the uniform control of the potential, it is often necessary to implement the temporary or permanent ground potential lapping operation on the construction lead wire. Such lapping is usually carried out in high altitude, high voltage or complex environment, and puts forward higher requirements for the contact reliability, electrical stability and operation efficiency.

[0003] The traditional ground potential connection process mainly depends on the structural auxiliary devices such as connection plates, bolts and pressure connection pieces, and the construction lead wire is lapped with the running wire by manual method. Although this method is widely used, it has exposed many problems in actual engineering. First, the structural parts such as the connection plate often need to be pre-installed in a space and firmly supported on a foundation, and many construction environments in the transmission line such as the tower, cross arm or high-altitude span section do not have stable fixing conditions, which limits the use range of the traditional structural parts. Secondly, the contact pressure cannot be accurately controlled in the manual lapping process, and the contact resistance is easily increased, the potential is uneven, and even the local discharge phenomenon occurs due to insufficient force, uneven contact surface or residual conductor oxide layer, which further threatens the safety of system operation.

[0004] Under the condition of high-altitude operation, the use of connection plates for operation also significantly increases the operation time and safety risk. Due to the complicated construction process and frequent use of tools, the operating personnel are in a suspended state for a long time, which not only has high labor intensity, but also has many variables on site. The rework is often caused by the substandard contact quality, which affects the overall construction progress and cost control. In addition, the contact resistance after lapping is usually unstable, and it is difficult to guarantee the conductivity performance in the long-term operation process. Especially under the external interference factors such as wind vibration, temperature difference change, hot and humid environment, the contact point is prone to performance degradation, and even induces operation failure.

[0005] At present, there is still a lack of systematic method and standard specification for the ground potential lapping operation under the condition of no connection plate in the industry, especially in the key links such as constant voltage contact control, potential balancing mechanism and contact quality guarantee, which still mainly relies on the experience operation of the operating personnel, and lacks the standardized and parameterized technical system. This problem is particularly prominent in the construction of the line with voltage level of 66 kilovolts and above. With the extension of the power grid construction to high altitude, complex terrain and extreme climate areas, the construction environment is more severe, and it is urgent to develop innovative, highly adaptive and low-dependent ground potential lapping technology.

[0006] Therefore, in view of the above problems and limitations, the present application proposes a method for connecting the ground potential of the lead wire of the power transmission line without the terminal board based on the constant voltage control of electrical contact, aiming to solve the problems of strong dependence on the connection structure, uncontrollable contact pressure, large resistance fluctuation and low operation efficiency in the prior art. This method is particularly suitable for the ground potential connection of the 66kV voltage level power transmission line, and can realize reliable electrical connection between the lead wires without the terminal board, ensure the potential balance and contact stability during the operation, and significantly improve the construction efficiency and operation safety in the high-altitude operation environment. This method not only simplifies the connection operation process and reduces the dependence on the traditional connection structure, but also effectively suppresses the heat accumulation and electric erosion caused by poor contact while maintaining the safety of the operation potential, and has good engineering adaptability and application value.

[0007] The purpose of the present application is to provide a method for connecting the ground potential of the lead wire of the power transmission line without the terminal board based on the constant voltage control of electrical contact, which not only realizes the ground potential lead wire connection without the terminal board, but also significantly improves the contact reliability, electrical stability and high-altitude operation efficiency, and has good engineering adaptability and application value.

[0008] The technical solution of the present application to solve the above technical problems is as follows:

[0009] The present application provides a method for connecting the ground potential of the lead wire of the power transmission line without the terminal board based on the constant voltage control of electrical contact, and the specific steps are as follows:

[0010] S1: In the 66kV line construction, according to the connection operation drawing and the ground potential distribution requirement, the position of the lead wire ground potential connection point is determined, the external dirt and loose oxide layer of the lead wire is removed, the conductor surface is cleaned to meet the basic conditions for reliable contact in the subsequent operation;

[0011] S2: According to the wire specification, construction position and required contact resistance threshold, the required constant pressure contact force is calculated, the target crimping value suitable for 66kV ground potential transfer operation is set to ensure that the long-term electrical stability and anti-vibration performance after connection meet the operation specifications;

[0012] S3: The pretreated lead wire is introduced into the ground potential connection area, the precise fixation of the lead wire connection section is completed by using the electric positioning method, and the potential coupling structure is introduced to ensure the continuous conduction of the ground potential and avoid the problems of electric erosion caused by poor contact or potential suspension;

[0013] S4: After the lead wire is inserted into the connection hole, the self-adaptive clamping is realized by using the wedge-shaped elastic structure arranged in the hole, the wedge block is compressed when the wire is inserted, and the reverse tightening is realized under the action of the elastic force after positioning, so as to realize the self-locking fixation of the wire.

[0014] Alternatively, in step S1, the application first determines the reasonable overlap position of the target lead according to the 66 kV transmission line connection diagram and the field operation layout before implementing the overlap operation. The selected area needs to avoid stress points, angle turning points or high-vibration areas, and preferentially selects linear straight sections and ensures the operable space. Then, the surface of the overlap section of the lead is treated mechanically and chemically, and the surface attached oil, oxide layer and corrosion products are polished or cleaned by using a steel wire brush or abrasive cloth, and a non-corrosive conductor cleaning liquid can be optionally used for auxiliary cleaning. Through this step, the initial contact resistance of the overlap surface is significantly reduced, providing a basis for forming a high-quality contact interface.

[0015] Alternatively, in step S2, the application establishes a correlation model between the contact pressure and the contact resistance according to the conductor specifications (such as cross-sectional shape, material, and stranding type) of the lead, the overlap length, the resistance limit value and the field construction environment (wind load, temperature difference, etc.), and determines the required constant pressure crimping force and its distribution range through empirical parameters or simulation analysis. The crimping force setting should ensure that the resistance is less than the specification limit under reasonable contact area, while considering the vibration resistance performance and long-term structural stability. An elastic adjustment mechanism and control time logic are introduced during the crimping process, and a matched constant pressure control tool is selected to realize standardized operation, improve contact consistency and controllability.

[0016] Alternatively, in step S3, after completing the lead pretreatment, the lead is accurately introduced into the ground potential overlap area by an electric positioning device to realize accurate alignment and stable fixation of the overlap section. During the process, a potential coupling structure is introduced in combination with the lead arrangement structure to ensure that the overlap point has continuous potential conduction capability, effectively eliminating the transient potential difference and suspended potential problems at the contact site, avoiding the phenomena of electric erosion, electric arc or thermal damage caused by poor contact and uneven potential, and improving the electrical safety and system compatibility of the overlap process.

[0017] Alternatively, in step S4, after completing the lead insertion and overlap positioning, a wedge-shaped elastic structure arranged in the wire clamp through hole is used to mechanically fix the lead. The structure is composed of a wedge block arranged on the inner wall of the wire through hole and a compression spring, and a specific angle sliding fit relationship is formed between the wedge block and the hole wall. When the lead is inserted, the wedge block slides axially along the hole and compresses the spring to leave a passage; after the lead is inserted, the spring drives the wedge block to slide reversely under the condition of no external force, and the conductor surface is compressed to form an axial clamping force. Through the wedge angle structure between the wedge block and the conductor, when the wire is subjected to back pull or vibration interference, the wedge block can produce a self-locking effect to automatically enhance the clamping force, thereby ensuring that the overlap structure has stable anti-sliding ability and reliable long-term mechanical holding force. This step realizes the bolt-free self-fixing of the wire in the overlap section, which is one of the key links for the application to realize efficient and reliable overlap connection.

[0018] The present application has the following beneficial effects:

[0019] The present application has the following beneficial effects: the method for connecting the ground potential of the lead wire of the power transmission line without the connection board based on the constant voltage control of the electric contact effectively breaks through the dependence of the traditional connection method on the connection board, bolts and other structural parts, solves the problems of difficult fixation, unstable contact and insufficient safety of the ground potential connection of the lead wire in high altitude and narrow space, etc. Through reasonable selection and surface cleaning of the connection position of the ground potential of the lead wire, the low-resistance contact basis is ensured; the constant voltage contact force calculation method is used to accurately define the target crimping value and improve the electrical stability of the connection; the electric positioning and potential coupling structure is introduced to realize high-precision alignment and continuous conduction of the ground potential, and the risk of electric erosion and breakdown caused by potential difference is avoided; the wedge elastic structure is used to realize self-locking clamping of the conductor, and the mechanical stability and anti-vibration ability of the connection part are enhanced. The overall method does not need to rely on the traditional connection board structure, is suitable for the lead wire connection operation of the 66 kilovolt power transmission line under complex working conditions such as high altitude and compact space, and has the engineering application advantages of high contact reliability, high construction efficiency and strong safety performance. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a flow chart of the method for connecting the ground potential of the lead wire of the power transmission line without the connection board based on the constant voltage control of the electric contact;

[0021] Figure 2 It is a detailed view of the internal structure of the lead wire clamp;

[0022] In the figure, 1 is a lead wire entry hole, 2 is a lead wire exit hole, 3 is a spring, 4 is a wedge-shaped movable clamping plate, and 5 is a lead wire connection device. DETAILED DESCRIPTION

[0023] The principles and characteristics of the present application are described below in combination with the drawings, and the examples are only used to explain the present application and are not used to limit the scope of the present application.

[0024] EMBODIMENT

[0025] The technical solution of the present application to solve the above technical problems is as follows:

[0026] The present application provides a method for connecting the ground potential of the lead wire of the power transmission line without the connection board based on the constant voltage control of the electric contact, as shown in Figure 1 The method comprises the following steps:

[0027] S1: in the 66 kilovolt line construction, according to the connection operation drawing and the ground potential distribution requirement, the lead wire ground potential connection point position is determined, the external dirt and loose oxide layer of the lead wire are removed, the conductor surface is cleaned to meet the basic conditions of reliable contact in the subsequent process;

[0028] Wherein, in the 66 kV power transmission line field operation, in order to ensure that the lap joint of the terminal without the terminal can form a stable, reliable and low resistance electrical connection, the selection logic of the lap joint point and the surface state of the conductor must be systematically processed. This step focuses on how to provide electrical and mechanical basis for subsequent constant voltage control crimping by scientifically positioning the lap joint position and fine conductor surface pretreatment technology.

[0029] 1. Technical selection principle of lap joint point position

[0030] In actual engineering, 66 kV conductors usually use steel core aluminum stranded wire (such as LGJ-400 / 50), the structure of which has a steel core and a peripheral stranded aluminum strand. The lap joint point should be preferentially selected in the uniform stranded section, and should not be close to the end of the tension concentration section, hoop or strain clamp, so as to prevent stress interference. The minimum safe distance of the lead lap joint point from the clamp should meet the following conditions:

[0031] D safe ≥10d+50mm (1)

[0032] Wherein, d is the outer diameter of the conductor (unit: mm); D safe is the minimum distance of the lap joint point from the clamp; the distance meets the mechanical buffer zone to avoid the influence of clamp disturbance on the original tension structure of the conductor.

[0033] In addition, in order to avoid the lap joint point after installation being located in the vibration antinode or node area of the conductor, it is necessary to evaluate the coupling relationship between the natural frequency f n of the conductor and the possible environmental excitation frequency (wind vibration, tower vibration, etc.), so as to ensure that the lap joint point does not form a resonance source. The vibration mode can be estimated as follows:

[0034]

[0035] Wherein, f n is the first order natural frequency of the conductor (Hz); L is the free hanging length of the lap joint section (m); T is the tension of the conductor (N); μ is the mass per unit length (kg / m). When f n is close to the wind excitation frequency, the lap joint position should be adjusted to avoid the resonance zone.

[0036] 2. Modeling and processing of conductor surface state

[0037] After the lap joint point is selected, the surface oxidation state of the lead wire needs to be graded and matched with the corresponding processing technology. The thickness of the oxidation layer on the surface of the steel core aluminum stranded wire often changes with the service life, environmental humidity and acid-base pollution degree. Its influence on the contact resistance can be approximately described by the following empirical model:

[0038]

[0039] Wherein, R cR = (ρ / A) ln(1 / r) is the contact resistance (Ω); ρ is the bulk resistivity of aluminum (about 2.8 x 10 -8 Ω·m); A eff is the effective contact area (m 2 ); R ox is the additional contact resistance of the oxide layer (Ω), which is related to the oxide layer thickness δ:

[0040]

[0041] where k is the surface impedance coefficient of the material; δ is the oxide layer thickness (μm); ∈ is the field penetration efficiency (related to the cleanliness of the conductor). It is found in experiments that the oxide layer thickness increases by 1 μm, R c increases by about 3-7 x 10 -5 Therefore, in high-requirement lapping processes, the oxide layer thickness should be controlled to be less than 3 μm.

[0042] 3. Implementation and evaluation of surface cleaning processes

[0043] In this example, the LGJ-400 / 50 type conductor lapping section was initially measured on site to have a moderate oxidation level, i.e., the average thickness of the oxide layer was about 4.2 μm. The following combined treatment process was used:

[0044] Initial cleaning: compressed air blowing + wiping with non-fiber cloth;

[0045] Mechanical polishing: using a hard steel wire brush (rotary type), polishing area ≥ 3 times the wire diameter, time 20 s;

[0046] Chemical cleaning: neutral copper-aluminum surface special cleaning agent, wiping 2 times, with 5 seconds of drying in between;

[0047] Electrical activation (optional): applying conductive paste (containing Zn-Al alloy particles) to improve the surface contact performance.

[0048] After the treatment is completed, a portable contact resistance measuring instrument (such as DL-RC2000 type, precision 10 μΩ) is used to test the contact resistance between the original conductor and the pre-contacting piece.

[0049] S2: According to the conductor specifications, construction location, and required contact resistance threshold, calculate the required constant pressure contact force, set the target crimping value suitable for 66 kV ground potential transfer operations, and ensure that the long-term electrical stability and anti-vibration performance after lapping meet the operation specifications;

[0050] Wherein, in order to ensure that the terminal block lap joint process forms a stable and reliable electrical connection, the application further introduces a constant pressure contact control mechanism on the basis of completing the conductor surface pretreatment, and the unit pressure of the lap joint area is accurately designed and constantly controlled. The core goal of the mechanism is to establish a uniform constant pressure contact state in the contact area through elastic loading and control retention means, control the lap joint resistance within the specification range, and avoid the deterioration of the contact electrical performance caused by local overpressure, pressure deviation or later loosening.

[0051] 1. Pressure contact area and pressure design The lead lap joint area usually presents a cylindrical surface contact structure, and the effective contact area A is determined by the conductor diameter D and the lap joint length L, and the calculation formula is as follows: In order to avoid local pressure being too high to cause aluminum stock crushing or steel core exposure, the lap joint length L is generally controlled within 2.5-3.5 times of the conductor diameter. The design of unit pressure p needs to meet the contact resistance target, and the recommended design range is: The corresponding total force F should meet: The conductor material is stranded aluminum wire, which has a certain elastic rebound ability during the pressure contact process, so the force value during the pressure contact process should be constant, and the pressure contact retention ability should be guaranteed, and the minimum retention time is not less than 15 seconds, so as to release the metal rebound stress.

[0059] 2. Elastic pressure contact control structure requirements

[0060] The constant pressure control described in the application must have the following characteristics:

[0061] (1) The output force is stable during the pressure contact process: the pressure contact tool needs to have a force limiter or a feedback mechanism to avoid inconsistent pressure caused by manual errors during operation;

[0062] (2) The loading process should be slow rising and slow falling: the pressure contact speed should be controlled within 0.5-1.5 mm / s to avoid impact loading damage to the contact surface;

[0063] (3) Allow the existence of elastic compensation structure: embed elastic elements (such as steel springs, oil cylinders) in the pressure contact structure, so that the small deformation in the contact process is automatically absorbed and compensated by the system;

[0064] (4) Load distribution uniformity: The crimping surface shape should cover the entire lap length, and have a curved surface fitting or semi-enclosed structure to improve the uniformity of unit pressure distribution.

[0065] 3. Contact resistance target value setting and feedback mechanism

[0066] The method sets the contact resistance target value R c No more than the following formula:

[0067]

[0068] Where, ρ is the bulk resistivity of aluminum, about 2.8×10 -8 Ω·m; A is the actual effective contact area (m2); ΔR surf is the additional contact resistance caused by micro-irregularities and oxidation residues, and the control target is usually less than 1.0×10 -4 Ω.

[0069] After crimping, contact resistance detection should be performed, and the detection tool should have the following technical conditions: precision grade better than ±10μΩ; constant current method is used for measurement, and the current is not less than 100mA; support on-site digital recording and calibration traceability.

[0070] The present application recommends combining crimping feedback data and contact resistance results to establish a crimping pressure-contact resistance mapping curve, which facilitates rapid matching of crimping parameters according to wire specifications in the later stage, and realizes rapid pressure adjustment and standardized operation.

[0071] 4. Crimping operation preparation and process parameter matching

[0072] Before formal crimping operation, the following technical preparations should be made:

[0073] (1) Calibrate the force value output accuracy of the crimping tool, with a deviation of not more than ±5%;

[0074] (2) Select the pressure target value according to the lap wire specifications, construction environment temperature, and conductor surface treatment;

[0075] (3) Set the constant pressure holding time control module or countdown device to ensure that the loading time meets the process stability requirements;

[0076] (4) Prepare detection tools such as conductive paste, infrared thermometer, and resistance tester as auxiliary means for quality evaluation;

[0077] (5) Clean the crimping area again to avoid dust or residual oil film affecting the crimping fitting effect.

[0078] S3: The pre-processed lead wire is introduced into the ground potential overlap area, the precision fixation of the lead wire overlap section is completed by using the electric positioning method, and the potential coupling structure is introduced to ensure the continuous conduction of the ground potential and avoid the problems of poor contact or potential suspension causing electric corrosion and the like;

[0079] Wherein, after the surface cleaning of the lead wire and the contact pressure parameter setting are completed, the two sections of the lead wire need to be accurately introduced into the ground potential overlap area, and the positional consistency and stability in the physical structure and the electrical state need to be ensured. The embodiment adopts the synergistic technical means of "electric positioning + potential coupling" to complete the high-precision fixation and potential synchronous control of the lead wire overlap section.

[0080] 1. Technical principle of electric positioning

[0081] The lead wire overlap needs to realize the axial alignment in the three-dimensional space, and the errors of the lead wire in the translation direction (X, Y) and the angle direction (θ) need to be controlled at the same time. In the present application, the automatic positioning is realized by using the electric drive device combined with the feedback positioning system. The system realizes the following precision target modeling through the closed-loop adjustment of the encoder, displacement sensor and controller.

[0082]

[0083] Wherein, Δ x , Δ y is the positional error of the lead wire in the plane direction; Δ θ is the angle error; r is the radius of the conductor;

[0084] Δ total is the overall position error of the overlap surface. In order to prevent the deflection or the warping of the contact surface after the crimping, the maximum tolerance of Δ total is set by the system and is corrected in real time by the program.

[0085] 2. Construction of potential coupling structure

[0086] In order to avoid the problems of discharge and breakdown caused by the potential difference between the two ends of the lead wire during the overlap process, the potential coupling structure is introduced before the overlap in the present embodiment. The structure can be regarded as a low-impedance path, and the equivalent resistance model thereof is:

[0087] R eq = R 导线 + 2·R 接触 (10)

[0088] Wherein, R 导线 is the body resistance of the flexible connecting line; R 接触 is the interface resistance of each end contacting with the conductor.

[0089] The present application effectively reduces R eq, the ground potential of both ends of the lead is synchronized.

[0090] According to Ohm's law of electrical path, the potential difference ΔV and the current I satisfy: Therefore, as long as is small enough, even if there is a transient induced current, ΔV can be maintained below the safety threshold to avoid the formation of a sharp discharge.

[0093] 3. Linkage control logic and protection strategy The entire electric positioning system and potential coupling structure are linked in the control system. The operation process is as follows: (1) Enter the alignment stage, the controller starts the servo system to drive the positioning slide to automatically search for position; (2) Real-time monitoring of the potential difference ΔV across the lap joint point, when the time limit allows the crimping to start; (3) If , the system suspends the crimping operation and indicates a potential anomaly; (4) After the positioning is locked, the system keeps the lead in the specified position for a certain period of time to ensure that there is no mechanical rebound risk of the conductor.

[0099] S4: After the lead is inserted into the lap joint hole, the wedge-shaped elastic structure inside the hole is used to achieve self-adaptive clamping. When the lead is inserted, the wedge block is compressed, and after positioning, it is tightened in the opposite direction under the action of the elastic force, achieving self-locking of the lead.

[0100] In this embodiment, to achieve self-adaptive clamping and long-term stable fixation after lead insertion, a set of wedge-shaped self-locking mechanisms are arranged inside the wire clamp through hole, specifically including a wedge block body, a compression spring, and a sliding guide groove. The wedge block is made of high-strength aluminum bronze material, and the surface is processed with an arc indentation matching the diameter of the lead. The indentation radius R wedge satisfies:

[0101] R wedge = R conductor ± 0.2mm (12)

[0102] to ensure that the compression surface can form effective contact without damaging the conductor. The wedge block and the hole form an included angle α, to prevent reverse slipping due to lead vibration, the wedge angle is set to:

[0103] α = 12 ~ 18° (13)

[0104] The angle range can meet the self-locking condition tan a < mu under the conventional aluminum strand surface friction coefficient mu = 0.3-0.35.

[0105] The compression spring adopts a disc spring group array, and the nominal compression stiffness k s is about:

[0106] k s = 80-120 N / mm (14)

[0107] The pre-tightening force meets the smooth displacement in the wire insertion process and the effective thrust after the wedge block resets. When the wire is inserted and the external force is released, the spring can provide the initial compression force of the wedge block within the recovery stroke Delta x = 2-3 mm:

[0108] F preload = k s * Delta x = 160-360 N (15)

[0109] When the lead wire has a pulling trend, the pre-tightening force is converted into a larger axial clamping force under the action of the wedge angle slope, forming a stable self-locking state. The structure has no obvious displacement under the condition that the lap wire is subjected to an axial disturbance of <= 100 N, the clamping force is stable, and has good vibration suppression and thermal expansion and contraction adaptability.

[0110] Meanwhile, the structure has good thermal expansion coordination of the compression mechanism parts in the operating temperature range of-25 DEG C to + 65 DEG C, ensures that the clamping force is maintained at more than 90% of the initial value in long-period operation, and meets the operating stability requirements of the outdoor 66 kV power transmission line on the lap structure.

[0111] The method for connecting the lead wire ground potential without a terminal block of a power transmission line based on the constant voltage control of electrical contact effectively breaks through the dependence of the traditional lap method on structural parts such as terminal blocks and bolts, solves the problems of difficult fixation, unstable contact and insufficient safety of the lead wire ground potential in high-altitude and narrow space, and the like. Through reasonable selection and surface cleaning of the lead wire ground potential lap position, the low-resistance contact basis is ensured; the constant voltage contact force calculation method is adopted to accurately define the target crimping value, and the lap electrical stability is improved; the electric positioning and potential coupling structure is introduced to realize high-precision alignment and continuous conduction of the ground potential, and the risk of electric erosion and breakdown caused by potential difference is avoided; the wedge type elastic structure is used to realize the self-locking clamping of the conductor, and the mechanical stability and vibration resistance of the lap position are enhanced. The overall method does not need to rely on the traditional terminal block structure, is suitable for the 66 kV power transmission line lead wire lap operation under complex working conditions such as high altitude and compact space, and has the engineering application advantages of high contact reliability, high construction efficiency and strong safety performance.

[0112] The remaining matters of the present application are known technologies.

[0113] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A method for ground potential connection of transmission line leads without a terminal block based on constant voltage control of electrical contact, characterized in that, Includes the following steps: S1: During the construction of 66 kV lines, based on the connection operation drawings and ground potential distribution requirements, the location of the ground potential connection point of the lead wire is determined, and the dirt and loose oxide layer on the outside of the lead wire are removed to ensure that the conductor surface is clean and to meet the basic conditions for subsequent reliable contact. S2: Calculate the required constant voltage contact force based on the conductor specifications, construction location and required contact resistance threshold, and set the target crimping value suitable for 66 kV ground potential transfer operations to ensure that the long-term electrical stability and vibration resistance performance after the connection meet the operating specifications. S3: The pre-treated lead wire is introduced into the ground potential overlap area. The lead wire overlap section is precisely fixed by electric positioning. A potential coupling structure is introduced to ensure continuous ground potential conduction and avoid problems such as electro-erosion caused by poor contact or potential floating. S4: After the lead wire is inserted into the lap hole, the wedge-shaped elastic structure set in the hole achieves self-adaptive clamping. When the wire is inserted, the wedge is compressed, and after positioning, it is tightened in the opposite direction under the action of elasticity, so as to achieve self-locking fixation of the wire.

2. The method for ground potential connection of transmission line leads without terminal block based on constant voltage control of electrical contact as described in claim 1, characterized in that, In step S1, the connection point of the lead wire to be connected is selected according to the connection operation drawing and the potential distribution requirements of the transmission line. The surface of the lead wire is cleaned by means of cleaning agent, wire brush, etc., to remove dirt, grease and loose oxide layer. According to the conductor surface roughness standard, the electrical performance of the contact area is ensured to meet the conduction requirements, so as to provide a low-resistance contact surface without insulation obstruction for subsequent electrical contact.

3. The method for ground potential connection of transmission line leads without terminal block based on constant voltage control of electrical contact as described in claim 1, characterized in that, In step S2, based on the conductor specifications, splicing area space limitations, electrical performance requirements, and construction height, empirical calculations and simulation modeling are used to calculate the target crimping force and pressure distribution range per unit area. Combined with the contact resistance safety value at a voltage level of 66 kV, constant voltage contact control parameters are set, including crimping force value, force application method, and minimum effective contact area, to ensure that the splicing structure meets the requirements for long-term stable conductive connection and resistance to mechanical vibration.

4. The method for ground potential connection of transmission line leads without terminal block based on constant voltage control of electrical contact as described in claim 1, characterized in that, In step S3, the pre-treated lead wire is introduced into the overlapping area by an electric positioning device to achieve precise control and stable fixation of the overlapping position; a potential coupling structure is introduced during the overlapping process to ensure continuous conduction of ground potential between the overlapping point and the busbar, and to prevent arc breakdown, electro-erosion corrosion or local floating potential phenomena caused by potential difference or uneven contact.

5. The method for ground potential connection of transmission line leads without terminal block based on electrical contact constant voltage control according to claim 1, characterized in that, In step S4, after the lead wire is inserted into the through hole of the wire clamp device, it is self-adaptively fixed by the wedge-shaped elastic clamping structure set in the hole. The wedge-shaped clamping structure includes a wedge block and a pre-compression spring set in the inner wall of the channel. When the lead wire is inserted, the wedge block compresses the spring in the sliding direction under the action of the axial thrust of the wire to make room. When the wire reaches the positioning position and the external force is released, the spring drives the wedge block to rebound in the opposite direction and stick tightly to the conductor surface. When the lead wire has an axial pull-back tendency, the wedge block and the wire form a clamping force that gets tighter and tighter through the wedge angle self-locking, so as to achieve stable fixation of the lapped wire under the condition of no bolt locking, and ensure that the lapped area has long-term vibration resistance, pull-back resistance and contact reliability.

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