Ring main unit cable connector temperature expansion compensation sliding rail device and using method thereof

Abstract

The invention relates to the technical field of power equipment, in particular to a ring main unit cable connector temperature expansion compensation sliding rail device and a using method thereof. The device comprises double sliding rails parallelly mounted on the inner wall of the ring main unit, sliding blocks are slidably embedded in sliding grooves of the sliding rails, springs are elastically connected between the sliding blocks and the sliding rails, and the sliding blocks are provided with adjustable clamping assemblies through connecting plates; the clamping assembly comprises an adjusting rod and a symmetrical cable clamp, spacing adjustment is achieved through a T-shaped block-T-shaped groove structure, and bolts are detachably locked. The use method comprises the steps of parameter acquisition and calculation, device assembly and adjustment, cable positioning and fixing, compensation performance detection and dynamic maintenance. The expansion and contraction displacement of the cable joint can be accurately compensated, cables of different specifications can be adapted, installation and maintenance are convenient, operation is stable and reliable, the cable joint is effectively prevented from being damaged due to expansion and contraction deformation, and safe operation of a power system is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of power equipment technology, and in particular to a temperature expansion compensation slide rail device for cable joints in ring main units and its usage method. Background Technology

[0002] As a core device in power distribution networks, the reliability of the cable joints inside ring main units directly determines the stability and security of power transmission. During power system operation, cable joints within the ring main unit experience thermal expansion and contraction due to factors such as changes in ambient temperature and fluctuations in load current, causing the cable length to stretch or shrink. If effective compensation measures are not taken, or if the compensation device is poorly designed, the cable joints will continuously bear tensile and compressive stresses. Under long-term effects, this can easily lead to problems such as insulation damage, loosening of joints, and increased contact resistance, which can then cause localized overheating, arcing, or even short-circuit faults. In severe cases, this can result in large-scale power outages, causing significant economic losses and social impact.

[0003] Currently, existing temperature compensation technologies for cable joints in ring main units mainly include rigid fixed buffers and rubber pad compensation, but these generally have many shortcomings. Firstly, the compensation accuracy is insufficient. Most devices use a fixed-stroke compensation structure, which cannot dynamically adapt to actual parameters such as cable material, laying length, and ambient temperature range, easily leading to over-compensation or under-compensation. Secondly, adaptability is poor. The clamping structure of traditional compensation devices is mostly of fixed specifications, making it difficult to accommodate cables of different outer diameters. When changing cable models, the entire clamping component needs to be replaced, increasing maintenance costs. Thirdly, long-term operational stability is poor. The elasticity of the elastic components cannot be adjusted in time after its elasticity decays, leading to a gradual decline in compensation performance and making it difficult to meet the requirements of long-term safe operation.

[0004] With the increasing demands for power supply reliability in power distribution networks, there is an urgent need for a ring main unit cable joint temperature expansion compensation device that is accurate, widely adaptable, and stable in operation, along with corresponding scientific usage methods, to address the shortcomings of existing technologies and ensure the safe and efficient operation of the power system. Summary of the Invention

[0005] This invention addresses the technical shortcomings of existing ring main unit (RNB) cable joint temperature compensation devices, such as low compensation accuracy, poor adaptability, and insufficient long-term operational stability. It provides a RNB cable joint temperature expansion compensation slide rail device and its usage method. Through precise structural design and a scientific operating procedure, it achieves accurate compensation for the thermal expansion and contraction displacement of the cable joint, improves the device's adaptability to cables of different specifications, ensures long-term stable operation, and thus prevents cable joint damage due to expansion and contraction deformation, reducing the incidence of power failures and ensuring the safe and reliable operation of the power distribution network system.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A temperature expansion compensation slide rail device for cable joints in a ring main unit includes two slide rails installed parallel to each other on the inner wall of the ring main unit. Each slide rail has a groove along its length, and the openings of the two grooves are opposite to each other. A slider is slidably embedded in the groove and can slide along the length of the slide rail. A connecting plate is fixedly connected to one side of each slider away from the slide rail, and a clamping assembly for clamping the cable is assembled between the two connecting plates. A spring is elastically connected between one side of each slider and the inner wall of the slide rail.

[0008] The clamping assembly includes multiple parallel and spaced adjusting rods, the two ends of which are fixedly connected to two connecting plates respectively. The multiple adjusting rods together form the support frame of the clamping assembly.

[0009] Each of the adjusting rods has a T-slot along its length, and two symmetrically arranged cable clamps are provided between the multiple adjusting rods. The cable clamps are adapted to the adjusting rods through a sliding structure.

[0010] The cable clamp has a semi-circular arc structure, with protruding blocks fixedly connected to both ends; the sliding structure includes T-shaped blocks fixedly connected to both sides of each protruding block, the T-shaped blocks being adapted to T-shaped grooves and slidably embedded in the T-shaped grooves.

[0011] The two protruding blocks at the same end of the two cable clamps are detachably locked together by bolts.

[0012] The method for using the temperature expansion compensation slide rail device for cable joints in ring main units includes the following steps:

[0013] S1: Based on the installation environment parameters of the ring main unit and the cable specifications, calculate the theoretical thermal expansion compensation of the cable joint and determine the pre-adjustment parameters of the slide rail device;

[0014] S2: The slide rail device is installed at a preset position on the inner wall of the ring main unit, and the initial position of the slider is achieved by adjusting the spring pre-compression.

[0015] S3: Adjust the relative distance between the two cable clamps in the clamping assembly according to the cable diameter specification, and achieve adaptive positioning of the cable clamps through the sliding structure;

[0016] S4: Place the cable connector between the two cable clamps and use a quantitative locking method to complete the detachable fixing of the cable;

[0017] S5: After installation, perform compensation performance testing and dynamically fine-tune the device parameters based on real-time temperature change data to ensure compensation accuracy.

[0018] Step S1 specifically includes:

[0019] 1.1 Collect basic parameters: Determine the effective fixing length L0 of the cable joint in the ring main unit through on-site measurement, obtain the extreme temperatures Tmax and Tmin of the operating environment by referring to the design documents of the ring main unit, determine the type of cable conductor material and find the corresponding coefficient of linear expansion α; at the same time, measure the outer diameter D of the cable to be fixed, and obtain the allowable compressive strength σ of the cable outer sheath by referring to the cable product manual;

[0020] 1.2 Calculate the core parameters: According to the formula:

[0021]

[0022] Calculate the theoretical thermal expansion compensation for the cable joint. =Tmax - Tmin; According to the formula:

[0023]

[0024] Determine the spring precompression, where To compensate for the safety factor, the value is selected based on the cable laying tension level: 1.1 for tension levels 1-2, 1.2 for levels 3-4, and 1.3 for levels 5 and above; the contact area S between the cable clamp and the cable is calculated based on the cable outer diameter D.

[0025]

[0026] The effective clamping length of the cable clamp, and then through Calculate the target clamping force, and finally apply the formula:

[0027]

[0028] Determine the bolt tightening torque, where K is the torque coefficient, selected according to the bolt material: 0.15 for carbon steel bolts and 0.12 for stainless steel bolts; d is the nominal diameter of the bolt.

[0029] Step S2 specifically includes:

[0030] 2.1 Slide rail installation: Clean the impurities on the pre-set installation surface inside the ring main unit to ensure that the installation surface is flat. Place the two slide rails parallel to each other on the installation surface and use a spirit level to calibrate the parallelism to ensure that the parallelism error is ≤0.5mm / m. Then, fix the slide rails firmly with expansion bolts. During the fixing process, continuously monitor the parallelism to avoid installation deviation.

[0031] 2.2 Spring pre-compression adjustment: Fix one end of the spring to the inner wall of the slide rail and the other end to the slider. Push the slider to slide along the slide groove so that the spring is compressed to the pre-compression amount x calculated in step 1.2. Use the probe of the dial indicator to press against the end face of the slider and read the displacement data in real time. When the displacement reaches x and stabilizes for 30 seconds, use a temporary positioning pin to temporarily fix the position of the slider.

[0032] 2.3 Lubrication Treatment: Apply wear-resistant grease evenly to the contact area between the slider and the groove, ensuring the grease covers the sliding contact surface of the slider. The application amount should be controlled at 0.2~0.3 g / cm². 2 After applying the coating, remove the temporary positioning pins and gently push the slider to check its smoothness and ensure there is no jamming.

[0033] Step S3 specifically includes:

[0034] 3.1 Assembly of adjusting rod and cable clamp: Confirm that both ends of the adjusting rod are fixedly connected to the connecting plate, and that multiple adjusting rods are arranged in parallel and spaced apart to form a support frame. Align the T-shaped blocks on both sides of the cable clamp with the T-shaped grooves of the adjusting rod, and slowly push them in so that the T-shaped blocks slide into the T-shaped grooves, ensuring that the two cable clamps are arranged symmetrically.

[0035] 3.2 Cable clamp spacing adjustment: Based on the cable outer diameter D measured in step 1.1, determine the target spacing between the two cable clamps, and push the two cable clamps to slide along the T-slot simultaneously. Observe the movement of the cable clamps during the sliding process to ensure that the two cable clamps move along the same axis. Use calipers to measure the spacing between the cable clamps. Stop pushing after the target spacing is reached.

[0036] 3.3 Concentricity Calibration: The concentricity of the two cable clamps is measured using a laser concentricity tester. The transmitter and receiver of the tester are aligned with the two ends of the two cable clamps respectively. After starting the tester, the concentricity error is read. If the error is >0.3mm, the position of the cable clamps is finely adjusted until the error is ≤0.3mm.

[0037] Step S4 specifically includes:

[0038] 4.1 Cable positioning and placement: Slowly place the cable joint section to be fixed between the two cable clamps, adjust the cable position so that the core connection part of the cable joint is aligned with the center position of the cable clamp, and use a ruler to measure the alignment deviation to ensure that the deviation is ≤1.0mm;

[0039] 4.2 Bolt quantitative tightening: Insert bolts between the corresponding protruding blocks at the same end of the two cable clamps, put on nuts, and apply torque using a torque wrench according to the tightening torque M calculated in step 1.2. Apply force at a constant speed during tightening to avoid sudden torque changes. After tightening, keep the torque wrench in the state for 3 seconds to ensure stable tightening.

[0040] 4.3 Fit Test: Use a feeler gauge to test the gap between the cable clamp and the cable. The test points are evenly distributed on the inner surface of the cable clamp. A total of 8 test points are selected. If there is a test point with a gap > 0.2mm, it means that the fit is not up to standard. The bolts need to be loosened, the position of the cable clamp needs to be readjusted, and then tightened again according to the preset torque until the gap of all test points is ≤ 0.2mm and the fit area is ≥ 90%.

[0041] Step S5 specifically includes:

[0042] 5.1 Simulated Temperature Environment Detection: Install temperature sensors and displacement sensors inside the ring main unit. The temperature sensor is placed near the cable joint, and the displacement sensor is aligned with the slider to detect the slider displacement. Start the temperature control system and gradually increase the ambient temperature from Tmin to Tmax at a rate of 2℃ / min. After each 5℃ increase, stabilize for 10 minutes and record the temperature value and slider displacement ΔL' at this time.

[0043] 5.2 Parameter Deviation Adjustment: Compare the measured displacement ΔL' at each temperature point with the theoretical compensation ΔL, and calculate the deviation rate. If the deviation rate is greater than 5%, according to the formula:

[0044]

[0045] Calculate the spring pre-compression adjustment amount, loosen the fixing bolts between the slide rail and the inner wall of the ring main unit, push the slide rail to fine-tune the spring compression amount, after adjustment, re-fix the slide rail, and perform simulated temperature detection again until the deviation rate is ≤5%;

[0046] 5.3 Dynamic Maintenance During Actual Operation: After the ring main unit is put into actual operation, the temperature sensor collects the temperature data of the cable joints in real time and transmits it to the monitoring system. The system automatically summarizes the temperature change data and slider displacement data every 24 hours. When the temperature change exceeds 10℃, it automatically issues a fine-tuning reminder. The operation and maintenance personnel perform dynamic fine-tuning according to the process in steps 5.1 to 5.2 to ensure that the device is always in a state of accurate compensation.

[0047] Working principle:

[0048] After the device is installed, the cable connector is firmly fixed by the clamping assembly. The clamping assembly is rigidly connected to the slider and the connecting plate. The slider is embedded in the slide rail groove and can slide freely. The slider and the slide rail are elastically connected by a spring, forming a telescopic compensation linkage structure. When the ambient temperature inside the ring main unit rises, the cable elongates due to heat, causing the clamping assembly to move synchronously. This pushes the slider along the slide rail groove towards the fixed end of the spring. The spring is compressed and stores elastic potential energy, achieving buffer compensation for the cable elongation. When the temperature drops, the cable contracts, the spring releases elastic potential energy, and pushes the slider to slide in the opposite direction along the slide rail groove, causing the clamping assembly to reset synchronously with the cable, compensating for the cable contraction.

[0049] The present invention has the following beneficial effects:

[0050] 1. High compensation accuracy: This invention accurately collects environmental and cable parameters, calculates the theoretical compensation amount using scientific formulas, and combines spring pre-compression adjustment and dynamic deviation correction to achieve accurate compensation for the thermal expansion and contraction displacement of cable joints. This effectively avoids damage to cable joints due to excessive stretching or compression, and reduces the risk of faults such as local overheating and short circuits.

[0051] 2. Wide adaptability: The clamping assembly adopts a T-block-T-slot sliding structure, which can flexibly adjust the cable clamp spacing according to different cable outer diameters. Combined with the detachable bolt locking design, it is compatible with various cable specifications.

[0052] 3. Stable and reliable operation: Through a long-term operation and maintenance mechanism of real-time monitoring and dynamic fine-tuning, the device is guaranteed to operate stably for a long time and its service life is extended. Attached Figure Description

[0053] Figure 1 This is a perspective view of the temperature expansion compensation slide rail device for cable joints in a ring main unit proposed in this invention.

[0054] Figure 2 This is a front view of the ring main unit cable joint temperature expansion compensation slide rail device proposed in this invention;

[0055] Figure 3 This is a structural diagram of the clamping assembly of the temperature expansion compensation slide rail device for cable joints in a ring main unit proposed in this invention;

[0056] Figure 4 This is a diagram of the slide rail structure of the ring main unit cable joint temperature expansion compensation slide rail device proposed in this invention.

[0057] Legend:

[0058] 1. Slide rail; 2. Slide groove; 3. Slider; 4. Spring; 5. Connecting plate; 6. Adjusting rod; 7. Cable clamp; 8. Extending block; 9. T-block; 10. T-slot; 11. Bolt; 12. Cable socket; 13. Cable; 14. Inner wall of ring main unit. Detailed Implementation

[0059] The present invention will be further described in detail below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] The ring main unit cable joint temperature expansion compensation slide rail device includes two slide rails 1 installed parallel to each other on the inner wall 14 of the ring main unit. Each slide rail 1 has a slide groove 2 along its length, and the openings of the two slide grooves 2 are arranged opposite each other. A slider 3 is slidably embedded in the slide groove 2 and can slide along the length of the slide rail 1. A connecting plate 5 is fixedly connected to the side of each slider 3 away from the slide rail 1, and a clamping assembly for clamping the cable is assembled between the two connecting plates 5. A spring 4 is elastically connected between one side of the slider 3 and the inner wall of the slide rail 1.

[0061] The core purpose of this structural design is to address the expansion and contraction of cables during operation due to changes in ambient temperature or load heat. Displacement compensation is achieved through the sliding engagement of the slider and the guide rail, preventing damage to cable joints from excessive pulling or compression. The guide rail is made of high-strength alloy material, with a smooth, wear-resistant coating on the inner side of the groove to reduce frictional resistance during slider movement and ensure smooth compensation action. The spring is made of corrosion-resistant stainless steel, with its elastic coefficient precisely calculated to provide stable restoring force to the slider and generate appropriate buffering force during cable expansion and contraction.

[0062] The clamping assembly includes multiple parallel, spaced-apart adjusting rods 6. Each adjusting rod 6 has its two ends fixedly connected to two connecting plates 5, and the multiple adjusting rods 6 together form the support frame of the clamping assembly. Each adjusting rod 6 has a T-slot 10 along its length. Two symmetrically arranged cable clamps 7 are positioned between the multiple adjusting rods 6, and the cable clamps 7 are connected to the adjusting rods 6 via a sliding structure. The cable clamp 7 has a semi-circular arc structure, with protruding blocks 8 fixedly connected to both ends. The sliding structure includes T-blocks 9 fixedly connected to both sides of each protruding block 8. The T-blocks 9 are adapted to the T-slots 10 and slidably embedded within them. The two protruding blocks 8 corresponding to the same end of the two cable clamps 7 are detachably locked together by bolts 11.

[0063] The parallel spacing of multiple adjusting rods evenly distributes the clamping force transmitted by the cable clamps, preventing localized stress concentration that could lead to deformation of the support frame. The adjusting rods are made of lightweight, high-strength aluminum alloy, effectively reducing the overall weight of the device while ensuring structural strength. The matching design of the T-slots and T-blocks serves both guiding and limiting functions, ensuring smooth sliding of the cable clamps along the length of the adjusting rods and preventing them from falling off after clamping the cable. The T-blocks also have a wear-resistant surface treatment, extending the service life of the sliding structure. The semi-circular inner wall of the cable clamp conforms to the curvature of the cable's outer sheath, and an insulating, anti-slip rubber pad is added to the inner side. This enhances the clamping stability and prevents damage to the cable sheath from excessive clamping force. The bolt locking mechanism is detachable, allowing for flexible adjustment of the spacing between the two cable clamps according to the cable diameter, improving the device's adaptability to different cable types and facilitating future maintenance and repair.

[0064] The method for using the temperature expansion compensation slide rail device for cable joints in ring main units includes the following steps:

[0065] S1: Based on the installation environment parameters of the ring main unit and the cable specifications, calculate the theoretical thermal expansion compensation of the cable joint and determine the pre-adjustment parameters of the slide rail device;

[0066] S2: The slide rail device is installed at a preset position on the inner wall of the ring main unit, and the initial position of the slider is achieved by adjusting the spring pre-compression.

[0067] S3: Adjust the relative distance between the two cable clamps in the clamping assembly according to the cable diameter specification, and achieve adaptive positioning of the cable clamps through the sliding structure;

[0068] S4: Place the cable connector between the two cable clamps and use a quantitative locking method to complete the detachable fixing of the cable;

[0069] S5: After installation, perform compensation performance testing and dynamically fine-tune the device parameters based on real-time temperature change data to ensure compensation accuracy.

[0070] Step S1 specifically includes:

[0071] 1.1 Collect basic parameters: Determine the effective fixing length L0 of the cable joint in the ring main unit through on-site measurement, obtain the extreme temperatures Tmax and Tmin of the operating environment by referring to the design documents of the ring main unit, determine the type of cable conductor material and find the corresponding coefficient of linear expansion α; at the same time, measure the outer diameter D of the cable to be fixed, and obtain the allowable compressive strength σ of the cable outer sheath by referring to the cable product manual;

[0072] 1.2 Calculate the core parameters: According to the formula:

[0073]

[0074] Calculate the theoretical thermal expansion compensation for the cable joint. =Tmax - Tmin; According to the formula:

[0075]

[0076] Determine the spring precompression, where To compensate for the safety factor, the value is selected based on the cable laying tension level: 1.1 for tension levels 1-2, 1.2 for levels 3-4, and 1.3 for levels 5 and above; the contact area S between the cable clamp and the cable is calculated based on the cable outer diameter D.

[0077]

[0078] The effective clamping length of the cable clamp, and then through Calculate the target clamping force, and finally apply the formula:

[0079]

[0080] Determine the bolt tightening torque, where K is the torque coefficient, selected according to the bolt material: 0.15 for carbon steel bolts and 0.12 for stainless steel bolts; d is the nominal diameter of the bolt.

[0081] Step S1 is the stage of collecting basic parameters and calculating core parameters for the installation and commissioning of the temperature expansion compensation slide rail device for the cable joint of the ring main unit. It is a crucial preliminary step to ensure that the device adapts to the operating characteristics of the cable, achieves accurate temperature expansion compensation, and ensures safe clamping and fixing. This step involves collecting actual on-site parameters through the system and consulting technical documents, combined with scientific formulas to calculate the core parameters. This provides accurate data support for subsequent operations such as device assembly and positioning, spring selection, cable clamp adjustment, and bolt tightening. It directly determines the reliability of the device's compensation effect and the safety of cable operation, effectively avoiding problems such as insufficient compensation, cable damage, or clamping failure caused by parameter deviations.

[0082] Step S2 specifically includes:

[0083] 2.1 Slide rail installation: Clean the impurities on the pre-set installation surface inside the ring main unit to ensure that the installation surface is flat. Place the two slide rails parallel to each other on the installation surface and use a spirit level to calibrate the parallelism to ensure that the parallelism error is ≤0.5mm / m. Then, fix the slide rails firmly with expansion bolts. During the fixing process, continuously monitor the parallelism to avoid installation deviation.

[0084] 2.2 Spring pre-compression adjustment: Fix one end of the spring to the inner wall of the slide rail and the other end to the slider. Push the slider to slide along the slide groove so that the spring is compressed to the pre-compression amount x calculated in step 1.2. Use the probe of the dial indicator to press against the end face of the slider and read the displacement data in real time. When the displacement reaches x and stabilizes for 30 seconds, use a temporary positioning pin to temporarily fix the position of the slider.

[0085] 2.3 Lubrication treatment: Apply wear-resistant grease evenly to the contact area between the slider and the groove, covering the sliding contact surface of the slider. The amount of grease should be controlled at 0.2~0.3g / cm². After application, remove the temporary positioning pin and gently push the slider to check the smoothness of sliding and ensure that there is no jamming.

[0086] Step S2 is the core assembly stage of the ring main unit cable joint temperature expansion compensation slide rail device. Through three key operations—precise slide rail fixing, spring pre-compression calibration, and lubrication of the sliding parts—the basic structure of the device is built and debugged, laying a solid structural foundation for subsequent cable clamping and fixing. The quality of this step directly affects the device's compensation accuracy, structural stability, and long-term operational reliability. Parallelism control of the slide rail installation is a prerequisite for smooth slider movement; precise control of spring pre-compression is crucial for effective temperature compensation; and lubrication reduces wear on sliding components and extends the device's service life.

[0087] Step S3 specifically includes:

[0088] 3.1 Assembly of adjusting rod and cable clamp: Confirm that both ends of the adjusting rod are fixedly connected to the connecting plate, and that multiple adjusting rods are arranged in parallel and spaced apart to form a support frame. Align the T-shaped blocks on both sides of the cable clamp with the T-shaped grooves of the adjusting rod, and slowly push them in so that the T-shaped blocks slide into the T-shaped grooves, ensuring that the two cable clamps are arranged symmetrically.

[0089] 3.2 Cable clamp spacing adjustment: Based on the cable outer diameter D measured in step 1.1, determine the target spacing between the two cable clamps, and push the two cable clamps to slide along the T-slot simultaneously. Observe the movement of the cable clamps during the sliding process to ensure that the two cable clamps move along the same axis. Use calipers to measure the spacing between the cable clamps. Stop pushing after the target spacing is reached.

[0090] 3.3 Concentricity Calibration: The concentricity of the two cable clamps is measured using a laser concentricity tester. The transmitter and receiver of the tester are aligned with the two ends of the two cable clamps respectively. After starting the tester, the concentricity error is read. If the error is >0.3mm, the position of the cable clamps is finely adjusted until the error is ≤0.3mm.

[0091] Step S3 is the fine assembly and calibration stage of the clamping components, which is a key step to ensure the stability and uniform force distribution of the subsequent cable clamping. Based on the basic parameters such as the cable outer diameter obtained in step S1, this step completes the precise matching and assembly of the adjusting rod and the cable clamp. Through spacing adjustment and concentricity calibration, it ensures that the two cable clamps form a symmetrical and coaxial clamping space, providing structural protection for the stable placement and uniform force distribution of the cable.

[0092] Step S4 specifically includes:

[0093] 4.1 Cable positioning and placement: Slowly place the cable joint section to be fixed between the two cable clamps, adjust the cable position so that the core connection part of the cable joint is aligned with the center position of the cable clamp, and use a ruler to measure the alignment deviation to ensure that the deviation is ≤1.0mm;

[0094] 4.2 Bolt quantitative tightening: Insert bolts between the corresponding protruding blocks at the same end of the two cable clamps, put on nuts, and apply torque using a torque wrench according to the tightening torque M calculated in step 1.2. Apply force at a constant speed during tightening to avoid sudden torque changes. After tightening, keep the torque wrench in the state for 3 seconds to ensure stable tightening.

[0095] 4.3 Fit Test: Use a feeler gauge to test the gap between the cable clamp and the cable. The test points are evenly distributed on the inner surface of the cable clamp. A total of 8 test points are selected. If there is a test point with a gap > 0.2mm, it means that the fit is not up to standard. The bolts need to be loosened, the position of the cable clamp needs to be readjusted, and then tightened again according to the preset torque until the gap of all test points is ≤ 0.2mm and the fit area is ≥ 90%.

[0096] Step S4 is the precise positioning and quantitative clamping stage for the cable, achieving a stable connection between the cable and the device, while quantitative control ensures that the clamping force meets safety standards. Cable positioning must ensure that the core of the connector is aligned with the clamping center to prevent misalignment under stress. Bolt tightening strictly follows the torque value calculated in step S1 to ensure moderate clamping force—neither insufficient clamping force causing cable slippage nor excessive clamping force damaging the cable sheath. Fit testing is the final verification of the clamping effect, ensuring full fit between the cable and the cable clamp, guaranteeing uniform force distribution.

[0097] Step S5 specifically includes:

[0098] 5.1 Simulated Temperature Environment Detection: Install temperature sensors and displacement sensors inside the ring main unit. The temperature sensor is placed near the cable joint, and the displacement sensor is aligned with the slider to detect the slider displacement. Start the temperature control system and gradually increase the ambient temperature from Tmin to Tmax at a rate of 2℃ / min. After each 5℃ increase, stabilize for 10 minutes and record the temperature value and slider displacement ΔL' at this time.

[0099] 5.2 Parameter Deviation Adjustment: Compare the measured displacement ΔL' at each temperature point with the theoretical compensation ΔL, and calculate the deviation rate |ΔL'-ΔL| / ΔL×100%. If the deviation rate > 5%, adjust according to the formula:

[0100]

[0101] Calculate the spring pre-compression adjustment amount, loosen the fixing bolts between the slide rail and the inner wall of the ring main unit, push the slide rail to fine-tune the spring compression amount, after adjustment, re-fix the slide rail, and perform simulated temperature detection again until the deviation rate is ≤5%;

[0102] 5.3 Dynamic Maintenance During Actual Operation: After the ring main unit is put into actual operation, the temperature sensor collects the temperature data of the cable joints in real time and transmits it to the monitoring system. The system automatically summarizes the temperature change data and slider displacement data every 24 hours. When the temperature change exceeds 10℃, it automatically issues a fine-tuning reminder. The operation and maintenance personnel perform dynamic fine-tuning according to the process in steps 5.1 to 5.2 to ensure that the device is always in a state of accurate compensation.

[0103] Step S5 is the stage for verifying the compensation performance of the device and ensuring long-term operation and maintenance. It is a crucial final step and long-term management link to ensure that the device accurately performs its compensation function under all temperature conditions. This step tests the compensation effect by simulating the actual temperature environment and makes precise adjustments for deviations that exceed the standard to ensure that the device meets the design compensation requirements. Subsequent dynamic maintenance during actual operation establishes a full life cycle guarantee mechanism. By monitoring temperature and displacement data in real time, it responds promptly to compensation needs caused by sudden temperature changes, avoids a decrease in compensation accuracy due to long-term operation, and ensures the long-term safe and stable operation of the cable joint.

[0104] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A temperature expansion compensation slide rail device for cable joints in a ring main unit, comprising two slide rails (1) installed parallel to each other on the inner wall (14) of the ring main unit, characterized in that: Each of the slide rails (1) has a groove (2) along its length, and the openings of the two grooves (2) are arranged opposite to each other; a slider (3) is slidably embedded in the groove (2), and the slider (3) can slide along the length of the slide rail (1); a connecting plate (5) is fixedly connected to the side of each of the two sliders (3) away from the slide rail (1), and a clamping assembly for clamping the cable is assembled between the two connecting plates (5); a spring (4) is elastically connected between one side of the slider (3) and the inner wall of the slide rail (1).

2. The ring main unit cable joint temperature expansion compensation slide rail device according to claim 1, characterized in that: The clamping assembly includes multiple parallel and spaced adjusting rods (6), the two ends of which are fixedly connected to two connecting plates (5) respectively, and the multiple adjusting rods (6) together form the support frame of the clamping assembly.

3. The ring main unit cable joint temperature expansion compensation slide rail device according to claim 2, characterized in that: Each of the adjusting rods (6) has a T-slot (10) along its own length direction, and two symmetrically arranged cable clamps (7) are provided between the multiple adjusting rods (6). The cable clamps (7) are adapted to the adjusting rods (6) through a sliding structure.

4. The ring main unit cable joint temperature expansion compensation slide rail device according to claim 3, characterized in that: The cable clamp (7) is a semi-circular arc structure, with protruding blocks (8) fixedly connected to both ends; the sliding structure includes T-shaped blocks (9) fixedly connected to both sides of each protruding block (8), the T-shaped blocks (9) are adapted to the T-shaped groove (10) and slidably embedded in the T-shaped groove (10).

5. The ring main unit cable joint temperature expansion compensation slide rail device according to claim 4, characterized in that: The two protruding blocks (8) at the same end of the two cable clamps (7) are detachably locked together by bolts (11).

6. The method of using the temperature expansion compensation slide rail device for cable joints in ring main units, characterized in that: Includes the following steps: S1: Based on the installation environment parameters of the ring main unit and the cable specifications, calculate the theoretical thermal expansion compensation of the cable joint and determine the pre-adjustment parameters of the slide rail device; S2: The slide rail device is installed at a preset position on the inner wall of the ring main unit, and the initial position of the slider is achieved by adjusting the spring pre-compression. S3: Adjust the relative distance between the two cable clamps in the clamping assembly according to the cable diameter specification, and achieve adaptive positioning of the cable clamps through the sliding structure; S4: Place the cable connector between the two cable clamps and use a quantitative locking method to complete the detachable fixing of the cable; S5: After installation, perform compensation performance testing and dynamically fine-tune the device parameters based on real-time temperature change data to ensure compensation accuracy.

7. The method of using the temperature expansion compensation slide rail device for cable joints of ring main units according to claim 6, characterized in that: Step S1 specifically includes: (1.1) Collect basic parameters: Determine the effective fixing length L0 of the cable joint in the ring main unit through on-site measurement, obtain the extreme temperatures Tmax and Tmin of the operating environment by referring to the design documents of the ring main unit, determine the type of cable conductor material and find the corresponding coefficient of linear expansion α; at the same time, measure the outer diameter D of the cable to be fixed, and obtain the allowable compressive strength σ of the cable outer sheath by referring to the cable product manual; (1.2) Calculate the core parameters: According to the formula: Calculate the theoretical thermal expansion compensation for the cable joint. =Tmax - Tmin; According to the formula: Determine the spring precompression, where To compensate for the safety factor, the value is selected based on the cable laying tension level: 1.1 for tension levels 1-2, 1.2 for levels 3-4, and 1.3 for levels 5 and above; the contact area S between the cable clamp and the cable is calculated based on the cable outer diameter D. The effective clamping length of the cable clamp, and then through Calculate the target clamping force, and finally apply the formula: Determine the bolt tightening torque, where K is the torque coefficient, selected according to the bolt material: 0.15 for carbon steel bolts and 0.12 for stainless steel bolts; d is the nominal diameter of the bolt. Step S2 specifically includes: (2.1) Slide rail installation: Clean the impurities on the pre-set installation surface inside the ring main unit to ensure that the installation surface is flat. Place the two slide rails parallel to each other on the installation surface and use a spirit level to calibrate the parallelism to ensure that the parallelism error is ≤0.5mm / m. Then fix the slide rails firmly with expansion bolts. During the fixing process, continuously monitor the parallelism to avoid installation deviation. (2.2) Spring pre-compression adjustment: One end of the spring is fixedly connected to the inner wall of the slide rail, and the other end is connected to the slider. Push the slider to slide along the slide groove so that the spring is compressed to the pre-compression amount x calculated in step 1.

2. Use the probe of the dial indicator to press against the end face of the slider and read the displacement data in real time. When the displacement reaches x and stabilizes for 30 seconds, use a temporary positioning pin to temporarily fix the position of the slider. (2.3) Lubrication treatment: Apply wear-resistant grease evenly to the contact area between the slider and the groove, covering the sliding contact surface of the slider, and control the amount of grease applied to be 0.2~0.3 g / cm. 2 After applying the coating, remove the temporary positioning pins and gently push the slider to check its smoothness and ensure there is no jamming.

8. The method of using the temperature expansion compensation slide rail device for cable joints of ring main units according to claim 6, characterized in that: Step S3 specifically includes: (3.1) Assembly of adjusting rod and cable clamp: Confirm that both ends of the adjusting rod are fixedly connected to the connecting plate, and that multiple adjusting rods are arranged in parallel and spaced apart to form a support frame. Align the T-shaped blocks on both sides of the cable clamp with the T-shaped groove of the adjusting rod, and slowly push them in so that the T-shaped blocks slide into the T-shaped groove, ensuring that the two cable clamps are arranged symmetrically. (3.2) Cable clamp spacing adjustment: Based on the cable outer diameter D measured in step 1.1, determine the target spacing between the two cable clamps, and push the two cable clamps to slide along the T-slot simultaneously. Observe the movement state of the cable clamps during the sliding process to ensure that the two cable clamps move along the same axis. Use calipers to measure the spacing between the cable clamps. Stop pushing after the target spacing is reached. (3.3) Concentricity calibration: Use a laser concentricity tester to test the concentricity of the two cable clamps. Align the transmitter and receiver of the tester with the two ends of the two cable clamps respectively. After starting the tester, read the concentricity error. If the error is >0.3mm, fine-tune the position of the cable clamps until the error is ≤0.3mm.

9. The method of using the temperature expansion compensation slide rail device for cable joints of ring main units according to claim 6, characterized in that: Step S4 specifically includes: (4.1) Cable positioning and placement: Slowly place the cable joint section to be fixed between the two cable clamps, adjust the cable position so that the core connection part of the cable joint is aligned with the center position of the cable clamp, and use a ruler to measure the alignment deviation to ensure that the deviation is ≤1.0mm; (4.2) Bolt quantitative locking: Insert bolts between the corresponding protruding blocks at the same end of the two cable clamps, put on nuts, and apply torque with a torque wrench according to the locking torque M calculated in step 1.

2. Apply force at a constant speed during the tightening process to avoid sudden torque changes. After tightening, keep the torque wrench in the state for 3s to ensure stable locking. (4.3) Fit test: Use a feeler gauge to test the gap between the cable clamp and the cable. The test points are evenly distributed on the inner surface of the cable clamp. A total of 8 test points are selected. If there is a test point with a gap > 0.2 mm, it means that the fit is not up to standard. The bolts need to be loosened, the position of the cable clamp needs to be readjusted, and then tightened again according to the preset torque until the gap of all test points is ≤ 0.2 mm and the fit area is ≥ 90%.

10. The method of using the ring main unit cable joint temperature expansion compensation slide rail device according to claim 6, characterized in that: Step S5 specifically includes: (5.1) Simulated temperature environment detection: Install temperature sensor and displacement sensor in ring network cabinet. The temperature sensor is placed close to the cable joint, and the displacement sensor is aligned with the slider to detect the slider displacement. Start the temperature control system and gradually increase the ambient temperature from Tmin to Tmax at a rate of 2℃ / min. After each 5℃ increase, stabilize for 10min and record the temperature value and slider displacement ΔL' at this time. (5.2) Parameter deviation adjustment: Compare the measured displacement ΔL' at each temperature point with the theoretical compensation ΔL, and calculate the deviation rate. If the deviation rate is greater than 5%, according to the formula: Calculate the spring pre-compression adjustment amount, loosen the fixing bolts between the slide rail and the inner wall of the ring main unit, push the slide rail to fine-tune the spring compression amount, after adjustment, re-fix the slide rail, and perform simulated temperature detection again until the deviation rate is ≤5%; (5.3) Dynamic maintenance during actual operation: After the ring main unit is put into actual operation, the temperature sensor collects the temperature data of the cable joint in real time and transmits it to the monitoring system. The system automatically summarizes the temperature change data and slider displacement data every 24 hours. When the temperature change exceeds 10℃, it automatically issues a fine-tuning reminder. The operation and maintenance personnel perform dynamic fine-tuning according to the process of steps 5.1 to 5.2 to ensure that the device is always in a state of accurate compensation.

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