Three-dimensional layout method for compact structure of ring main unit

Abstract

The invention particularly relates to a three-dimensional layout method for a compact structure of a ring main unit, which relates to the technical field of power equipment and comprises the following steps of: designing a three-dimensional space layout; key performance structure design; modeling simulation and optimization are carried out; and physical verification and improvement. According to the invention, the thermal infrared imager obtains temperature data to construct a temperature influence coefficient, the smoke generator is combined with video analysis software to obtain a heat dissipation flow hysteresis coefficient, the two coefficients are integrated to calculate a positioning evaluation coefficient, and quantitative evaluation of the heat dissipation performance of the installation position of the circuit breaker is realized; compared with traditional experience judgment and simple test, the heat dissipation bottleneck can be positioned more accurately; in the modeling simulation and optimization link, multiple professional software is used for multi-dimensional simulation, layout can be optimized in the design stage, and design defects are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of power equipment, and particularly to a three-dimensional layout method for a compact structure of a ring main unit (RMU). Background Art

[0002] Under the background of accelerating the construction of the smart grid and the new power system, as a core device for realizing power distribution, control, and protection in the distribution network, the structural design of the RMU directly affects the power supply reliability and operation and maintenance efficiency.

[0003] In the process of the three-dimensional layout design of the existing RMU, it is necessary to determine the positions of each compact structure. In order to meet the heat dissipation requirements of compact structures such as circuit breakers, after the three-dimensional layout design is completed, it is necessary to conduct a heat dissipation performance test on the circuit breaker to test whether the RMU meets the heat dissipation requirements of the circuit breaker, so as to cope with subsequent position adjustments of the internal components of the RMU.

[0004] In addition, in terms of the heat dissipation performance evaluation of the circuit breaker, the traditional method only obtains single-point temperature data through infrared thermometry, and cannot comprehensively reflect the heat dissipation efficiency in a complex air flow environment; while some technologies introducing smoke visualization only stay at the qualitative observation level and do not quantitatively correlate the flow field distribution with the equipment installation position.

[0005] Therefore, a three-dimensional layout method for the compact structure of the RMU is needed to address the above-mentioned problems. Summary of the Invention

[0006] The purpose of the present invention is to propose a three-dimensional layout method for the compact structure of the RMU in order to solve the above problems.

[0007] In order to achieve the above purpose, the present invention adopts the following technical solutions: A three-dimensional layout method for the compact structure of the RMU includes: Three-dimensional space layout design: Planning the overall architecture of the RMU in a hierarchical manner, arranging the electrical components in each functional module, and reserving space for wiring and maintenance; Key performance structure design: Conducting special structure design based on the requirements of insulation, heat dissipation, and pressure relief protection performance; Modeling, simulation, and optimization: Constructing a three-dimensional model of the RMU, conducting multi-dimensional simulation analysis, and optimizing the layout design according to the results; Physical verification and improvement: Making a physical model according to the design scheme, carrying out performance tests, and iteratively optimizing according to the test results until reaching the standard; including conducting a heat dissipation performance test on the circuit breaker, collecting and analyzing the data during the test, obtaining a positioning evaluation coefficient, and determining whether the installation position of the circuit breaker is reasonable based on the positioning evaluation coefficient.

[0008] Preferably, the planning and module division: according to the application scenario of the ring main unit, clarify the functional requirements and size restrictions, disassemble the functional modules and determine the core parameters.

[0009] Preferably, the three-dimensional space layout design specifically includes: overall architecture planning and refined arrangement of components; Overall architecture planning: Layered layout: The top floor is equipped with an instrument room for easy operation and monitoring; the middle floor is used for the busbar room to install the main busbar, and the circuit breaker room accommodates the circuit breaker and operating mechanism; the bottom floor cable room is responsible for cable laying; load-bearing analysis is carried out; Detailed arrangement of components: Busbar room: The main busbar is fixed to the top plate with high-strength ceramic insulators, and the branch busbars are bolted and coated with conductive paste; short-circuit thermal effect and dynamic stability calculations are performed to ensure the safety of the busbar under short-circuit conditions; Circuit breaker room: The vacuum circuit breaker is installed vertically, and the operating mechanism is connected to the moving contact through a connecting rod; the opening and closing process is simulated using ADAMS software; Cable room: install cable brackets; calculate the short-circuit force of the cables to ensure reliable fixation; Instrument room: The inner wall is covered with a copper foil shielding layer, and the signal line uses twisted pair cable; instruments are installed according to functional areas.

[0010] Preferably, the key performance structure design specifically includes: insulation enhancement design, heat dissipation system construction and pressure relief protection system; Insulation enhancement design specifically includes material selection, distance control and structural optimization; The construction of the heat dissipation system specifically includes natural heat dissipation and forced heat dissipation; The pressure relief protection system specifically includes pressure relief design and protection upgrade.

[0011] Preferably, the modeling, simulation and optimization specifically include: Use Solid Works for parametric modeling and associate dimensions through equations; shell out non-critical parts to reduce model weight; Build a model in Ansys Maxwell, set material conductivity properties, apply rated voltage boundary conditions, solve the electric field distribution, and optimize the insulation structure; Use Fluent to set environmental and cooling parameters and simulate the rated load temperature distribution; Using Ansys Mechanical to simulate transportation vibration conditions, we ensured that the cabinet stress was less than the material yield strength; Improve your design based on simulation results.

[0012] Preferably, the specific includes: The cabinet body is processed by laser cutting, bending and welding technology; When assembling, use a torque wrench to control the pre-tightening force of the bolts and match with a lock washer. Electrical tests: For the insulation resistance test, use a preset voltage and keep it for 1 min. A value ≥ 1000 MΩ is qualified; for the power frequency withstand voltage test, it is 42 kVAC for 1 min without breakdown and flashover; for the partial discharge test, at a voltage of 1.5Un, the discharge amount ≤ 10 pC within 10 min; for the short-circuit test, verify the reliability of the circuit breaker's opening and closing under a short-circuit current of 25 kA / 3 s. Mechanical tests: The operating mechanism is run in first and then continuously opened and closed. Record the operating force and time, and check the contact wear amount after the test. Protection tests: For the dust-proof test, keep it in the dust-proof box for 8 h with no dust inside; for the waterproof test, use a 6.3 mm nozzle, spray water at a distance of 3 m with a water volume of 12.5 L / min for 3 min, and there is no water seepage in the cabinet; for the salt spray test, for 48 h, there is no obvious corrosion on the surface.

[0013] Preferably, for the heat dissipation performance test of the circuit breaker, collect and analyze the data during the test process to obtain a positioning evaluation coefficient, which specifically includes: Use an infrared thermal imager to scan the surface of the circuit breaker, detect the heat generation points at the contact connections, arc extinguishing chambers, and cable terminals, obtain the corresponding temperature data, and analyze the temperature data to obtain a temperature influence coefficient. Place a smoke generator at the ventilation opening of the cabinet and observe the data information on the smoke flow direction, which specifically includes: Smoke generator: Select a smoke source with low concentration, no residue, and high visibility. Auxiliary tool: Use a strong flashlight to irradiate the smoke from the side and shoot a video of the smoke flow direction. Environmental preparation: Close the doors, windows or fans near the cabinet to avoid interference from external strong airflows during the test; ensure that the cabinet is in a power-off state to avoid short circuits caused by smoke contacting live parts; clean the dust on the surface of the ventilation opening to avoid obstruction by sundries affecting the real air flow path. Analyze the data information on the smoke flow direction to obtain a heat dissipation stagnation coefficient. Comprehensively analyze the temperature influence coefficient and the heat dissipation stagnation coefficient to obtain a positioning evaluation coefficient. Preset a threshold for the positioning evaluation coefficient, compare the positioning evaluation coefficient with the threshold for the positioning evaluation coefficient. If the positioning evaluation coefficient is less than the threshold for the positioning evaluation coefficient, it is judged that the installation position of the circuit breaker meets the heat dissipation requirements. If the positioning evaluation coefficient is greater than the threshold for the positioning evaluation coefficient, it is judged that the installation position of the circuit breaker does not meet the heat dissipation requirements.

[0014] Preferably, the process of obtaining the temperature influence coefficient includes: Obtain the temperatures of the contact connection points, arc extinguishing chambers, and cable terminal heating points at preset time intervals, and preset the temperature thresholds for the contact connection points, arc extinguishing chambers, and cable terminal heating points respectively; successively subtract the temperature thresholds of the contact connection points, arc extinguishing chambers, and cable terminal heating points from the temperatures of the contact connection points, arc extinguishing chambers, and cable terminal heating points; Take the absolute value of the values less than 0, and mark them as the contact temperature difference value, arc extinguishing temperature difference value, and terminal temperature difference value respectively; and exclude the values greater than 0; Arrange the contact temperature difference values, arc extinguishing temperature difference values, and terminal temperature difference values obtained at each time interval in descending order according to the numerical size, and extract the maximum contact temperature difference value, arc extinguishing temperature difference value, and terminal temperature difference value, and mark them as the contact temperature difference extreme value, arc extinguishing temperature difference extreme value, and terminal temperature difference extreme value respectively; Obtain the acquisition time points of the contact temperature difference extreme value, arc extinguishing temperature difference extreme value, and terminal temperature difference extreme value respectively, and the time points when the temperatures of the contact connection points, arc extinguishing chambers, and cable terminal heating points are less than the corresponding temperature thresholds before the time points of the contact temperature difference extreme value, arc extinguishing temperature difference extreme value, and terminal temperature difference extreme value, and record the corresponding time points as the contact normal point, arc extinguishing chamber normal point, and cable terminal normal point respectively; Record the time differences between the acquisition time points of the contact temperature difference extreme value, arc extinguishing temperature difference extreme value, and terminal temperature difference extreme value and their corresponding contact normal points, arc extinguishing chamber normal points, and cable terminal normal points as the contact temperature rise duration, arc extinguishing temperature rise duration, and terminal temperature rise duration respectively; Perform product calculations on the contact temperature rise duration, arc extinguishing temperature rise duration, and terminal temperature rise duration and their corresponding contact temperature difference extreme value, arc extinguishing temperature difference extreme value, and terminal temperature difference extreme value respectively to obtain the contact temperature quantization value, arc extinguishing temperature quantization value, and terminal temperature quantization value; Use the contact temperature quantization value and arc extinguishing temperature quantization value as the major semi-axis and minor semi-axis of the ellipse respectively to establish an ellipse model, use the terminal temperature quantization value as the height of the ellipse model to establish an ellipsoid, and calculate the volume of the ellipsoid, which is recorded as the temperature influence coefficient.

[0015] Preferably, the obtaining process of the heat dissipation stagnation coefficient includes: Divide the interior of the ring main unit into regions according to the heat dissipation and ventilation path of the circuit breaker; Mark the movement trajectories of smoke particles frame by frame through video analysis software to generate a streamline diagram and a velocity vector diagram; perform cross-correlation calculation on the displacements of smoke particles in two consecutive frames of images to obtain a two-dimensional velocity field, and mark it as the average smoke flow velocity; Mark the area where smoke particles with an average smoke flow velocity less than 0.1 m / s stay as the stagnant area; Obtain the areas of each stagnant area, and divide the sum of the areas of each stagnant area by the total area of the area covered by smoke to obtain the stagnant area ratio; Draw a circle with the position of the circuit breaker as the center and a preset size radius, and mark all the stagnant areas involved in the circle; then sort the stagnant areas in ascending order according to their average smoke flow velocity, extract the three areas with the smallest average smoke flow velocity, and mark them as the analysis areas; Obtain the area centers of the analysis areas respectively, and successively connect the adjacent analysis area centers with straight lines to obtain a reference triangle composed of three straight lines; Obtain the overlapping area between the reference triangle and the circuit breaker, and record it as the heat dissipation stagnation coefficient.

[0016] To sum up, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows: 1. The present invention obtains the temperature influence coefficient by using an infrared thermal imager to acquire temperature data, obtains the heat dissipation stagnation coefficient by using a smoke generator in combination with video analysis software, and comprehensively calculates and locates the evaluation coefficient by combining the two, realizing the quantitative evaluation of the heat dissipation performance of the circuit breaker installation position; compared with traditional empirical judgment and simple testing, it can more accurately locate the heat dissipation bottleneck; in the modeling, simulation and optimization links, multi-dimensional simulations are carried out using a variety of professional software, and the layout can be optimized at the design stage to reduce design defects.

[0017] 2. The present invention conducts systematic and refined design from multiple dimensions such as planning and module division, three-dimensional spatial layout, and key performance structure design. In the planning stage, closely combined with the application scenario, transportation and installation conditions, and national standards, the functional requirements and core parameters are accurately determined, so that the ring main unit can be adapted to both the narrow urban space and the large current scenario in industrial parks. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the following description of the exemplary embodiments in conjunction with the drawings, more details, features and advantages of the present application are disclosed. In the drawings: Figure 1 is a flow chart of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following will describe several embodiments of the present application in more detail with reference to the drawings so that those skilled in the art can implement the present application. The present application can be embodied in many different forms and purposes and should not be limited to the embodiments described herein. These embodiments are provided to make the present application comprehensive and complete, and to fully convey the scope of the present application to those skilled in the art. The embodiments do not limit the present application.

[0020] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the relevant art and / or the context of this specification, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0021] Please refer to Figure 1 As shown, the present invention provides a technical solution: A three-dimensional layout method for the compact structure of a ring main unit, comprising: Planning and module division: Based on the application scenario of the ring main unit, transportation and installation conditions, and national standards, clarify the functional requirements and dimensional limitations, disassemble functional modules such as the busbar chamber and circuit breaker chamber, and determine the core parameters; Specifically including: Clarify the demand parameters: Application scenario adaptation: The ring main unit used in urban distribution networks needs to meet the installation in narrow spaces, such as underground cable wells and old community distribution rooms, requiring miniaturized design and a protection level of IP65 or above to resist moisture and dust invasion; The ring main unit in industrial parks focuses on high current carrying capacity, such as in chemical and steel enterprises, where the rated current often needs to be ≥1250A, and it is necessary to strengthen heat dissipation and short-circuit withstand capacity; Transportation and installation limitations: During road transportation, according to the "Regulations on the Administration of Over-limit Vehicles Traveling on Highways", the size of the ring main unit needs to adapt to the limitations of a single-axis load of 10 tons and a total height of 4 meters; If sea transportation is involved, it needs to fit into the internal space of a 20-foot container (5.898m × 2.352m × 2.385m) or a 40-foot container (12.032m × 2.352m × 2.385m). During on-site installation, it is necessary to consider the width and height of the distribution room passage, as well as the opening range of the equipment door, etc.; Strictly follow the standards: Strictly implement standards such as GB / T11022 and DL / T404. For 10kV ring main units, the phase-to-phase and phase-to-ground insulation distances are required to be ≥125mm (air insulation), and for 35kV ring main units, this distance is ≥300mm; The protection level is at least IP65 for outdoor type and at least IP44 for indoor type; The copper bar temperature rise is limited to ≤65K at an ambient temperature of 40°C; The short-circuit withstand current generally needs to reach 20kA / 3s (10kV) or 25kA / 3s (35kV); Disassemble the functional modules: Busbar Chamber: As the core of power transmission, it needs to be accurately selected according to the rated current. Copper busbars have high conductivity (58 MS / m) and are suitable for high-current and high-reliability scenarios; aluminum busbars have low cost and light weight and are mostly used in cost-sensitive projects. For example, for a 630A current, a 60×6mm² copper bar (rated current of about 700A) can be selected, and for 1250A, a 100×10mm² copper bar (rated current of about 1300A) is required. At the same time, the temperature rise is calculated through the formula to ensure that the temperature rise during operation ≤ 65K; Circuit Breaker Chamber: Compare vacuum circuit breakers with the characteristics of circuit breakers. The arc extinguishing medium of vacuum circuit breakers is vacuum ( ), suitable for voltage levels of 10~35kV, breaking current of 25~50kA, mechanical life ≥ 10000 times, and no greenhouse gas emissions; The circuit breaker uses gas (0.3~0.5MPa) for arc extinguishing, with a wider applicable voltage range (10~220kV) and a breaking current of 40~63kA, but it is a strong greenhouse gas (GWP = 23900); in terms of the operating mechanism, the spring operating mechanism is suitable for frequent operations, and the opening and closing time ≤ 50ms; the permanent magnet operating mechanism has a simple structure and high reliability; Cable Chamber: According to the cable specifications (such as YJV22~8.7 / 15kV~3×300), reserve enough space for the bending radius, generally not less than 20 times the outer diameter of the cable. The cables are fixed using C-type cable clamps, and the clamping force under short-circuit electrodynamic force needs to be calculated to ensure ≥ 500N. At the cable inlet and outlet, a combination of fireproof mud and fireproof board is used for sealing, with a fire resistance limit ≥ 1h; when passing through the floor, a 100mm thick fireproof isolation layer is set; Instrument Chamber: Following ergonomics, the installation height of the instruments is controlled at 800~1700mm, the operating handle force ≤ 50N, and the display screen is inclined at 15°~30° downward horizontally to prevent reflection. Shielded cables and twisted pairs are used, with the shielding layer grounded at a single point, the line spacing between different voltage levels ≥ 50mm, 10% spare terminals are reserved on the terminal block, and the wires are distinguished by phase as A yellow, B green, and C red; Mechanism Chamber: Optimize the transmission efficiency through the formula to ensure ≥ 90%. Use a PLC to control the motor to simulate more than 10000 opening and closing operations, and record parameters such as the opening and closing time and contact wear in real time to ensure stable performance; Three-dimensional Space Layout Design: The overall structure of the ring main unit is planned in a layered or zoned manner, and the electrical components in each functional module are arranged in a refined manner, reserving space for wiring and maintenance; Specifically include: overall structure planning and refined component layout; Hierarchical layout: An instrument room with a height of 500 mm is set on the top layer for easy operation and monitoring; the middle layer is 1200 mm high, with 300 mm for installing the main bus in the busbar chamber and 900 mm for accommodating the circuit breaker and operating mechanism in the circuit breaker chamber; the bottom layer is an 800-mm-high cable chamber responsible for cable laying; load-bearing analysis is carried out through SolidWorks Simulation to ensure that the top layer load ≤ 100 kg / m², the middle layer ≤ 300 kg / m², and the bottom layer ≤ 200 kg / m²; Zonal layout: Functional areas are separated by epoxy resin plates with a thickness of 8 mm or SMC composite partitions. The electric field distribution is simulated using AnsysMaxwell to ensure that the maximum field strength ≤ 20 kV / cm. A 50 - 100 mm wiring and maintenance channel is reserved between regions; Fine layout of components: Busbar chamber: The main busbar is fixed to the top plate by high-strength ceramic insulators (creepage distance ≥ 400 mm), and the branch busbars are bolt-connected and coated with conductive paste; short-circuit thermal effect and dynamic stability calculations are carried out to ensure the safety of the busbar under short-circuit conditions; Circuit breaker chamber: The vacuum circuit breaker is installed vertically and fixed to a special bracket with 4 M12 bolts. The operating mechanism is connected to the moving contact through a connecting rod; the opening and closing process is simulated using ADAMS software to ensure that the contact moving speed ≥ 1.5 m / s and the bounce time ≤ 2 ms; the ventilation holes are optimized using Fluent software to make the air flow velocity around the circuit breaker ≥ 0.5 m / s; Cable chamber: Three layers of cable brackets with a spacing of 300 mm are set, and C-type cable clips are used to fix the cables; the short-circuit force on the cables is calculated to ensure reliable fixation; a humidity sensor is installed, and the heating and dehumidification device is started when the relative humidity ≥ 80%; a 5% slope drainage trough is set at the bottom; Instrument room: A copper foil shielding layer (grounding resistance ≤ 1 Ω) is laid on the inner wall, and twisted pairs (twisted ≥ 30 times per meter) are used for signal lines; instruments are installed according to functional areas, and internal metal wire troughs are classified for wiring with clear markings; Key performance structural design: Based on the requirements of insulation, heat dissipation, and pressure relief protection performance, special structural design is carried out to ensure the electrical safety, efficient heat dissipation, and reliable protection of the ring main unit; Specifically, it includes: insulation strengthening design, heat dissipation system construction, and pressure relief protection system; The insulation strengthening design specifically includes material selection, distance control, and structural optimization; Material selection: Epoxy resin plates with an electrical strength ≥ 30 kV / mm are selected for insulation partitions; insulators are made of silicone rubber material with a tracking resistance index CTI ≥ 600; bushings are epoxy resin cast and designed with umbrella skirts to increase the creepage distance; Distance control: The insulation distance between the live parts and the cabinet body of the 10 kV ring main unit shall be ≥ 150 mm, and the phase-to-phase distance shall be ≥ 125 mm; for the 35 kV ring main unit, the corresponding distances shall be ≥ 350 mm and ≥ 300 mm respectively, and conductors with different potentials shall be isolated by partitions. Structural optimization: The breaker contacts adopt "epoxy resin casting + silicone rubber outer sheath" composite insulation, and the creepage distance specific to pollution degree III shall be ≥ 3.1 mm / kV. The construction of the heat dissipation system specifically includes natural heat dissipation and forced heat dissipation. Natural heat dissipation: On the top of the cabinet body, there are louver ventilation holes with a size of 200×100 mm and a spacing of 300 mm, and on the side, there are ventilation holes with a size of 150×80 mm and a spacing of 250 mm. Forced heat dissipation: According to the formula, axial fans are configured. For example, when the heat generation power is 500 W and the temperature difference is 10 K, a fan with an air volume of (432 m³ / h) is required; when the temperature sensor detects that the temperature exceeds 40 °C, it will be automatically started. The pressure relief and protection system specifically includes pressure relief design and protection upgrade. Pressure relief design: According to the IEC62271~200 standard, the pressure relief area ; rupture discs are installed on the top of the breaker compartment and the cable compartment, and they will rupture and relieve pressure when the pressure exceeds 0.2 MPa. The pressure relief opening faces the unoccupied area. Protection upgrade: The cabinet body is made of 2-mm-thick stainless steel plate, and the surface is sprayed with an outdoor anti-corrosion powder coating, reaching the IP65 protection level. Sealing rubber rings are provided at the cable inlet and outlet for dust and water protection. Modeling, simulation and optimization: A three-dimensional model of the ring main unit is constructed, and multi-dimensional simulation analyses such as electrical, thermal field, and mechanical strength are carried out, and the layout design is optimized according to the results. Specifically, it includes: Parametric modeling is carried out using Solid Works, and the dimensions are associated through equations (such as the height of the busbar compartment = the height of the breaker + 150 mm) for convenient modification; the non-critical components are shelled to reduce the model weight and improve the simulation efficiency. A model is established in Ansys Maxwell, the properties such as the electrical conductivity of the material are set, the rated voltage boundary condition is applied, the electric field distribution is solved, and the insulation structure is optimized (such as adding a shielding cover) to ensure that the electric field strength ≤ 20 kV / cm. The environment and heat dissipation parameters are set in Fluent to simulate the temperature distribution under the rated load; for example, for a certain 1250 A ring main unit, the simulation shows that the busbar connection is overheated, which is solved by adding heat sinks and optimizing ventilation. With the help of Ansys Mechanical, the transportation vibration (10~150 Hz, 1 g acceleration) condition is simulated to ensure that the stress of the cabinet body is less than the yield strength of the material and the safety factor ≥ 2.5. Improve the design according to the simulation results, such as adding partition plates or changing the conductor shape at the over-standard electric field; adding heat sinks and adjusting the fan position in the high-temperature area of the thermal field; strengthening the cabinet structure at the mechanical stress concentration point, and repeatedly simulating until reaching the standard; Physical verification and improvement: Fabricate a physical model according to the design scheme, conduct comprehensive performance tests on electricity, mechanics, protection, etc., and iteratively optimize according to the test results until reaching the standard; including the heat dissipation performance test of the circuit breaker, collecting and analyzing the data during the test, obtaining the positioning evaluation coefficient, and determining whether the installation position of the circuit breaker is reasonable based on the positioning evaluation coefficient; Fabricate a physical model according to the design scheme and conduct performance tests, specifically including: The cabinet is processed using laser cutting (accuracy ±0.1mm), bending (angle deviation ≤±0.5°), and welding (seam width deviation ≤±0.3mm) processes; When assembling, use a torque wrench to control the pre-tightening force of the bolts and match with lock washers; Electrical tests: For the insulation resistance test, use a 2500VDC voltage for 1 minute, and ≥1000MΩ is qualified; for the power frequency withstand voltage test, 42kVAC for 1 minute without breakdown and flashover; for the partial discharge test, at a voltage of 1.5Un (15kV), the discharge amount ≤10pC within 10 minutes; for the short-circuit test, verify the reliability of the circuit breaker's opening and closing under a short-circuit current of 25kA / 3s; Mechanical tests: The operating mechanism is first run in 50 times, and then continuously opened and closed 10000 times (60 times per hour). Record the operating force and time every 1000 times, and check the contact wear amount (≤0.5mm) after the test; Protection tests: For the dust-proof test, it lasts for 8 hours in a dust-proof box with no dust inside; for the waterproof test, use a 6.3mm nozzle, spray water at a distance of 3m with a water volume of 12.5L / min for 3 minutes, and there is no water seepage in the cabinet; for the salt spray test, 48 hours with no obvious corrosion on the surface; The positioning evaluation coefficient, the specific acquisition includes: Use an infrared thermal imager to scan the surface of the circuit breaker, detect the heat generation points at the contact connection, arc extinguishing chamber, and cable terminals, obtain the corresponding temperature data, and analyze the temperature data to obtain the temperature influence coefficient; The process of obtaining the temperature influence coefficient includes: Obtain the temperatures of the heat generation points at the contact connection, arc extinguishing chamber, and cable terminals at a preset time interval, and respectively preset the temperature thresholds for the heat generation points at the contact connection, arc extinguishing chamber, and cable terminals; subtract the temperature thresholds of the heat generation points at the contact connection, arc extinguishing chamber, and cable terminals from the temperatures of the heat generation points at the contact connection, arc extinguishing chamber, and cable terminals in turn; Take the absolute value of the values less than 0, and mark them as the contact temperature difference value, arc extinguishing temperature difference value, and terminal temperature difference value respectively; and eliminate the values greater than 0; The contact temperature difference values, arc extinguishing temperature difference values, and terminal temperature difference values obtained at each time interval are sorted in descending order according to their numerical magnitudes, and the maximum contact temperature difference value, arc extinguishing temperature difference value, and terminal temperature difference value are extracted and marked as the contact temperature difference extreme value, arc extinguishing temperature difference extreme value, and terminal temperature difference extreme value respectively; The acquisition time points of the contact temperature difference extreme value, arc extinguishing temperature difference extreme value, and terminal temperature difference extreme value are obtained respectively, and the time points before the time points of the contact temperature difference extreme value, arc extinguishing temperature difference extreme value, and terminal temperature difference extreme value, when the temperatures of the contact connection, arc extinguishing chamber, and cable terminal heating points are less than the corresponding temperature thresholds, are obtained respectively, and the corresponding time points are denoted as the contact normal point, arc extinguishing chamber normal point, and cable terminal normal point; The time differences between the acquisition time points of the contact temperature difference extreme value, arc extinguishing temperature difference extreme value, and terminal temperature difference extreme value and their corresponding contact normal points, arc extinguishing chamber normal points, and cable terminal normal points are denoted as the contact temperature rise duration, arc extinguishing temperature rise duration, and terminal temperature rise duration respectively; The contact temperature rise duration, arc extinguishing temperature rise duration, and terminal temperature rise duration are respectively multiplied by their corresponding contact temperature difference extreme value, arc extinguishing temperature difference extreme value, and terminal temperature difference extreme value to obtain the contact temperature quantization value, arc extinguishing temperature quantization value, and terminal temperature quantization value; Taking the contact temperature quantization value and arc extinguishing temperature quantization value as the major semi-axis and minor semi-axis of the ellipse respectively, an ellipse model is established, and taking the terminal temperature quantization value as the height of the ellipse model, an ellipsoid is established, and the volume of the ellipsoid is calculated and denoted as the temperature influence coefficient; A smoke generator is placed at the ventilation opening of the cabinet body, and the smoke flow direction data information is observed, specifically including: Smoke generator: Select a smoke source with low concentration, no residue, and high visibility; such as a portable smoke test pen, a special aerosol generator), and avoid using harmful smoke (such as mosquito coils, cigarettes) to pollute the cabinet body or affect the equipment; Auxiliary tool: Use a strong flashlight to irradiate the smoke from the side and shoot a video of the smoke flow direction; Environmental preparation: Close the doors, windows or fans near the cabinet body to avoid interference from external strong airflows during the test; ensure that the cabinet body is in a power-off state to avoid short circuits caused by smoke contacting live parts; clean the dust on the surface of the ventilation opening to avoid obstruction by sundries and affect the true air flow path; After analyzing the smoke flow direction data information, the heat dissipation stagnation coefficient is obtained; The acquisition process of the heat dissipation stagnation coefficient includes: The interior of the ring main unit is divided into regions according to the heat dissipation and ventilation path of the circuit breaker; The motion trajectories of smoke particles are marked frame by frame through video analysis software (such as Tracker, PIVlab) to generate a streamline diagram and a velocity vector diagram; the cross-correlation calculation is performed on the displacements of smoke particles in two consecutive frames of images to obtain a two-dimensional velocity field, which is marked as the average smoke flow velocity; The calculation formula is: ; wherein , is the velocity component of the i-th particle in the x and y directions, and N is the total number of particles; Mark the area where smoke particles stay with an average smoke flow velocity less than 0.1 m / s as the stagnant area; Obtain the area of each stagnant area, and after accumulating the areas of each stagnant area and dividing by the total area of the area covered by smoke, obtain the stagnant area ratio; Draw a circle with the position of the circuit breaker as the center and a preset size radius, and mark all the stagnant areas involved in the circle; and sort them in ascending order according to the average smoke flow velocity of each stagnant area, and extract the three areas with the smallest average smoke flow velocity, and mark them as the analysis areas; Obtain the center of each analysis area respectively, and connect the centers of adjacent analysis areas with straight lines in turn to obtain a reference triangle composed of three straight lines; Obtain the overlapping area between the reference triangle and the circuit breaker, and record it as the heat dissipation stagnation coefficient; After comprehensively analyzing the temperature influence coefficient and the heat dissipation stagnation coefficient, obtain the positioning evaluation coefficient; Mark the temperature influence coefficient and the heat dissipation stagnation coefficient as and respectively, and then substitute them into the formula: ; to obtain the positioning evaluation coefficient ; wherein and are the maximum allowable value of the temperature influence coefficient and the reference value of the heat dissipation stagnation coefficient respectively; a1 and a2 are the weight factors of the temperature influence coefficient and the heat dissipation stagnation coefficient respectively; Preset the positioning evaluation coefficient threshold, compare the positioning evaluation coefficient with the positioning evaluation coefficient threshold. If the positioning evaluation coefficient is less than the positioning evaluation coefficient threshold, it is judged that the installation position of the circuit breaker meets the heat dissipation requirements; If the positioning evaluation coefficient is greater than the positioning evaluation coefficient threshold, it is judged that the installation position of the circuit breaker does not meet the heat dissipation requirements.

[0022] The above formulas are all obtained by collecting a large amount of data for software simulation and selecting a formula close to the true value. The influence weight factors and specific coefficient values in the formula are set by those skilled in the art according to the actual situation and can be adjusted and modified later.

[0023] The foregoing description of the embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A three-dimensional layout method for the compact structure of a ring main unit, characterized in that Including: Three-dimensional space layout design: The overall structure of the ring main unit is planned in a layered manner, electrical components in each functional module are arranged, and space for wiring and maintenance is reserved; Key performance structure design: Based on the requirements of insulation, heat dissipation, and pressure relief protection performance, special structure design is carried out; Modeling, simulation and optimization: A three-dimensional model of the ring main unit is constructed, multi-dimensional simulation analysis is carried out, and the layout design is optimized according to the results; Physical verification and improvement: An entity model is made according to the design scheme, performance tests are carried out, and iterative optimization is carried out according to the test results until the standards are met; Among them, it includes the heat dissipation performance test of the circuit breaker, collecting and analyzing the data during the test process to obtain the positioning evaluation coefficient, and determining whether the installation position of the circuit breaker is reasonable based on the positioning evaluation coefficient.

2. The three-dimensional layout method of the compact structure of the ring main unit according to claim 1, characterized in that Planning and module division: According to the application scenario of the ring main unit, the functional requirements and size limitations are clarified, the functional modules are disassembled and the core parameters are determined.

3. The three-dimensional layout method of the compact structure of the ring main unit according to claim 2, characterized in that, Three-dimensional space layout design specifically includes: overall structure planning and refined component layout; Overall structure planning: Layered layout: An instrument room is set on the top floor for easy operation and monitoring; the middle layer is used for the main busbar room to install the main busbar, and the circuit breaker room accommodates the circuit breaker and the operating mechanism; the bottom layer cable room is responsible for cable laying; load-bearing analysis is carried out; Refined component layout: Main busbar room: The main busbar is fixed to the top plate by high-strength ceramic insulators, and the branch busbars are bolt-connected and conductive paste is applied; short-circuit thermal effect and dynamic stability calculations are carried out to ensure the safety of the busbar under short-circuit conditions; Circuit breaker room: The vacuum circuit breaker is installed vertically, and the operating mechanism is connected to the moving contact through a connecting rod; the opening and closing process is simulated using ADAMS software; Cable room: Cable brackets are set; the short-circuit force on the cable is calculated to ensure reliable fixation; Instrument room: A copper foil shielding layer is laid on the inner wall, and twisted pair wires are used for signal lines; instruments are installed according to functional partitions.

4. The three-dimensional layout method of the compact structure of the ring main unit according to claim 3, characterized in that, Key performance structure design specifically includes: insulation strengthening design, heat dissipation system construction, and pressure relief protection system; Insulation strengthening design specifically includes material selection, distance control, and structure optimization; Heat dissipation system construction specifically includes natural heat dissipation and forced heat dissipation; Pressure relief protection system specifically includes pressure relief design and protection upgrade.

5. The three-dimensional layout method for the compact structure of the ring main unit according to claim 4, characterized in that Modeling, simulation and optimization specifically include: Parametric modeling is carried out using Solid Works, and dimensions are related through equations; the non-critical components are shelled to reduce the model weight; A model is established in Ansys Maxwell, the electrical conductivity properties of the materials are set, the rated voltage boundary conditions are applied, the electric field distribution is solved, and the insulation structure is optimized; The environment and heat dissipation parameters are set in Fluent to simulate the temperature distribution under rated load; The transportation vibration conditions are simulated with the help of Ansys Mechanical to ensure that the stress of the cabinet body is less than the yield strength of the material; The design is improved according to the simulation results.

6. The three-dimensional layout method of the compact structure of the ring main unit according to claim 5, characterized in that, An entity model is made according to the design scheme, and performance tests are carried out, specifically including: Laser cutting, bending, and welding processes are used for cabinet processing; When assembling, a torque wrench is used to control the pre-tightening force of the bolts, and anti-loosening washers are used; Electrical tests: For the insulation resistance test, a preset voltage is applied for 1 minute. A value ≥ 1000 MΩ is considered qualified. For the power frequency withstand voltage test, it is 42 kVAC for 1 minute without breakdown or flashover. For the partial discharge test, at a voltage of 1.5Un, the discharge amount should be ≤ 10 pC within 10 minutes. The short-circuit test verifies the reliability of the circuit breaker's opening and closing under a short-circuit current of 25 kA / 3 s. Mechanical tests: The operating mechanism is first run in, then continuously opened and closed, and the operating force and time are recorded. After the test, the wear amount of the contacts is checked. Protection tests: For the dust-proof test, it lasts for 8 hours in a dust-proof chamber with no dust inside. For the waterproof test, a 6.3 mm nozzle is used, at a distance of 3 m, and water is sprayed at a rate of 12.5 L / min for 3 minutes, with no water seepage in the cabinet. For the salt spray test, it lasts for 48 hours with no obvious surface corrosion.

7. The three-dimensional layout method of the compact structure of the ring main unit according to claim 6, characterized in that, For the heat dissipation performance test of the circuit breaker, the data during the test process is collected and analyzed to obtain the positioning evaluation coefficient, specifically including: Use an infrared thermal imager to scan the surface of the circuit breaker, detect the heat generation points at the contact connections, arc extinguishing chambers, and cable terminals, obtain the corresponding temperature data, and analyze the temperature data to obtain the temperature influence coefficient. Place a smoke generator at the ventilation opening of the cabinet and observe the data information on the smoke flow direction, specifically including: Smoke generator: Select a smoke source with low concentration, no residue, and high visibility. Auxiliary tool: Use a strong flashlight to irradiate the smoke from the side and shoot a video of the smoke flow direction. Environmental preparation: Close the doors, windows or fans near the cabinet to avoid interference from external strong airflows during the test; ensure that the cabinet is in a power-off state to prevent the smoke from contacting live parts and causing a short circuit; clean the dust on the surface of the ventilation opening to avoid debris blocking and affecting the true airflow path. Analyze the data information on the smoke flow direction to obtain the heat dissipation stagnation coefficient. Comprehensively analyze the temperature influence coefficient and the heat dissipation stagnation coefficient to obtain the positioning evaluation coefficient. Preset the threshold of the positioning evaluation coefficient, compare the positioning evaluation coefficient with the threshold of the positioning evaluation coefficient. If the positioning evaluation coefficient is less than the threshold of the positioning evaluation coefficient, it is judged that the installation position of the circuit breaker meets the heat dissipation requirements. If the positioning evaluation coefficient is greater than the threshold of the positioning evaluation coefficient, it is judged that the installation position of the circuit breaker does not meet the heat dissipation requirements.

8. The three-dimensional layout method of the compact structure of the ring main unit according to claim 7, characterized in that The process of obtaining the temperature influence coefficient includes: Obtain the temperatures of the heat generation points at the contact connections, arc extinguishing chambers, and cable terminals at a preset time interval, and respectively preset the temperature thresholds for the heat generation points at the contact connections, arc extinguishing chambers, and cable terminals; successively subtract the temperature thresholds for the heat generation points at the contact connections, arc extinguishing chambers, and cable terminals from the temperatures of the heat generation points at the contact connections, arc extinguishing chambers, and cable terminals. Take the absolute value of the values less than 0, and respectively mark them as the contact temperature difference value, arc extinguishing temperature difference value, and terminal temperature difference value; and eliminate the values greater than 0. Arrange the contact temperature difference values, arc extinguishing temperature difference values, and terminal temperature difference values obtained at each time interval in descending order according to the numerical size, and extract the maximum contact temperature difference value, arc extinguishing temperature difference value, and terminal temperature difference value, and respectively mark them as the contact temperature difference extreme value, arc extinguishing temperature difference extreme value, and terminal temperature difference extreme value. Obtain the acquisition time points of the extreme values of the contact temperature difference, the arc extinguishing temperature difference, and the terminal temperature difference respectively, and the time points corresponding to the temperatures of the contact connection, the arc extinguishing chamber, and the cable terminal heating point being less than the corresponding temperature thresholds before the time points of the extreme values of the contact temperature difference, the arc extinguishing temperature difference, and the terminal temperature difference, and record the corresponding time points as the contact normal point, the arc extinguishing chamber normal point, and the cable terminal normal point respectively; Record the time differences between the acquisition time points of the extreme values of the contact temperature difference, the arc extinguishing temperature difference, and the terminal temperature difference and their corresponding contact normal point, arc extinguishing chamber normal point, and cable terminal normal point as the contact temperature rise duration, the arc extinguishing temperature rise duration, and the terminal temperature rise duration respectively; Perform product calculations on the contact temperature rise duration, the arc extinguishing temperature rise duration, and the terminal temperature rise duration respectively and their corresponding extreme values of the contact temperature difference, the arc extinguishing temperature difference, and the terminal temperature difference to obtain the contact temperature quantization value, the arc extinguishing temperature quantization value, and the terminal temperature quantization value; Take the contact temperature quantization value and the arc extinguishing temperature quantization value as the major semi-axis and the minor semi-axis of the ellipse respectively to establish an ellipse model, take the terminal temperature quantization value as the height of the ellipse model to establish an ellipsoid, and calculate the volume of the ellipsoid, which is denoted as the temperature influence coefficient.

9. The three-dimensional layout method of the compact structure of the ring main unit according to claim 1, characterized in that The acquisition process of the heat dissipation stagnation coefficient includes: Divide the interior of the ring main unit according to the heat dissipation and ventilation path of the circuit breaker; Mark the movement trajectories of the smoke particles frame by frame through video analysis software to generate a streamline diagram and a velocity vector diagram; perform cross-correlation calculation on the displacements of the smoke particles in two consecutive frames of images to obtain a two-dimensional velocity field, and mark it as the average smoke flow velocity; Mark the area where the smoke particles with an average smoke flow velocity less than 0.1 m / s stay as the stagnant area; Obtain the areas of each stagnant area, and divide the sum of the areas of each stagnant area by the total area of the area covered by the smoke to obtain the stagnant area ratio; Draw a circle with the position of the circuit breaker as the center and a preset size radius, and mark all the stagnant areas involved in the circle; and arrange them in ascending order according to the average smoke flow velocity of each stagnant area, extract the three areas with the smallest average smoke flow velocity, and mark them as the analysis areas; Obtain the regional centers of the analysis areas respectively, and connect the adjacent regional centers with straight lines in turn to obtain a reference triangle composed of three straight lines; Obtain the overlapping area between the reference triangle and the circuit breaker, and denote it as the heat dissipation stagnation coefficient.

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