A power distribution box with overheat grading protection and a control method

Abstract

The application provides a power distribution box with overheat grading protection and a control method. The application can distinguish overall environmental changes and local abnormal changes, and can adapt to power distribution boxes of different models and different configurations without complex on-site calibration work. The application can capture deviation signals before the fault develops to a dangerous threshold, thereby realizing early warning, greatly advancing the response time of overheat protection, and significantly improving the sensitivity of early fault identification. The application can accurately distinguish primary hot spots and secondary temperature rises, and the protection action can be accurately limited to the fault branch, thereby avoiding large-area power failure caused by heat diffusion in the prior art, maximizing the continuity of power supply of normal branches, eliminating secondary misjudgments caused by the heat diffusion coupling effect, realizing precise targeted protection, and having important practical value for industrial production scenes with strict power supply reliability requirements.

Description

Technical Field

[0001] This invention relates to the field of distribution box technology, and specifically to a distribution box and control method with graded overheat protection. Background Technology

[0002] As the final stage of power distribution in a power distribution system, the reliability of the distribution box directly affects power supply safety. In actual operation, overheating frequently occurs inside the distribution box due to the thermal effect of load current, the gradual degradation of terminal contact resistance, and changes in ambient temperature. Statistics show that insulation aging and short-circuit fires caused by overheating account for a significant proportion of electrical fires.

[0003] Currently, the main method for overheat protection of distribution boxes is to install multiple monitoring points inside the box. When any sensor detects a temperature value or rate of temperature rise exceeding a preset threshold, an alarm or circuit breaker tripping action is triggered. However, this method has the following drawbacks in practical applications: (1) The conductor cross-sectional area, heat capacity and heat dissipation conditions are different in different locations in the distribution box. The preset threshold of each monitoring point should be different. If a unified threshold is adopted, the risk of missed reporting for locations with large heat capacity will increase, and the risk of false reporting for locations with small heat capacity will increase. If the threshold is calibrated separately for each monitoring point, the problem of large on-site calibration workload and difficulty in promotion will be faced.

[0004] (2) The degradation of contact resistance is a gradual process. The absolute value of the temperature rise rate in the early stages of a fault often has not yet exceeded the preset threshold. When a terminal becomes slightly loose, causing an increase in contact resistance, its temperature rise rate may only increase from the baseline value of 0.5℃ / min to 0.7℃ / min, while the set alarm threshold is usually 1.0℃ / min. At this time, the single-point threshold scheme will determine that "the system is normal", but the relative change at this point has already indicated the early development of the fault. Relying solely on the absolute threshold can easily lead to a serious lag in fault detection.

[0005] (3) Heat diffusion leads to secondary false alarms and improper expansion of the protection range. When a terminal block forms a local hot spot due to poor contact, heat will spread to the adjacent parts through copper busbars, air convection and other means, causing the temperature rise rate of the adjacent normal parts to also increase, which will be judged as a fault point, and thus trigger the protection action of the branch where it is located. This can easily lead to a local poor contact fault being amplified into a power outage accident in multiple branches, seriously sacrificing the continuity of power supply.

[0006] Therefore, how to accurately identify faults and take reasonable overheat protection measures based on the corresponding faults is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a distribution box and control method with graded overheat protection.

[0008] The technical solution adopted by this invention is as follows: The first aspect of this invention provides a distribution box with graded overheat protection, including a box body. The box body contains a plurality of electrical components and terminal blocks. The electrical components and terminal blocks have a plurality of electrical connection points for fixing wires with terminal bolts. The invention is characterized by setting monitoring points for each electrical connection point, and further includes a multi-point temperature sensor array for temperature detection at each monitoring point, and a control module electrically connected to the multi-point temperature sensor array. The control module is configured as follows: The temperature change rate of each monitoring point is calculated based on the temperature collected at each monitoring point within a preset sampling period, and a spatial distribution matrix of temperature rise rate composed of the temperature change rates of each monitoring point is constructed. Calculate the spatial difference and concentration parameters of the spatial distribution matrix of the temperature rise rate, compare them with the preset spatial difference and concentration thresholds, and determine whether the current overheating mode is an equilibrium temperature rise mode or a local hot spot mode. When the temperature rise is determined to be in a balanced temperature rise mode, a global response strategy is executed; when the temperature rise is determined to be in a local hot spot mode, the temperature change rate of each monitoring point is corrected based on the preset thermal diffusion coefficient to distinguish between primary hot spots and secondary temperature rise locations, and a targeted protection strategy is executed to locate the branch where the primary hot spot is located.

[0009] Preferably, the distribution locations of the monitoring points include the electrical connection points of the main incoming line terminals and / or the electrical connection points of the incoming terminals of each branch circuit breaker and / or the electrical connection points of the outgoing terminals of each branch circuit breaker and / or the electrical connection points of the busbar connections.

[0010] Preferably, the spatial variability parameter is obtained by calculating the standard deviation of the spatial distribution matrix of the temperature rise rate, and the concentration parameter is obtained by calculating the ratio of the maximum temperature rise rate to the mean.

[0011] Preferably, the global response strategy includes calculating the comprehensive environmental thermal stress index S based on the internal and external temperatures of the enclosure. env Based on this index, forced air cooling is initiated and / or the overload protection current threshold is dynamically adjusted.

[0012] Preferably, S env The response level is determined by comparing the response with multiple preset thresholds S1, S2, and S3: when S... env When S1 < S1, the system maintains normal operation; when S1 ≤ S env When S2 < S2, initiate a level 1 response, activating the built-in forced air cooling fan to operate at a fixed duty cycle; when S2 ≤ S envWhen <S3, the secondary response is initiated, the cooling fan runs at full speed, and the overload protection current threshold of the main circuit is dynamically reduced according to the preset temperature compensation curve, with the reduction amount being the same as S. env Proportional; when S env When the value is ≥S3, a Level 3 response is initiated. Based on the Level 2 response, an early warning message indicating excessive environmental thermal stress in the distribution box is sent to the monitoring platform via the communication interface.

[0013] Preferably, the targeted protection strategy includes implementing graded measures based on the urgency of heat accumulation.

[0014] A second aspect of the present invention provides a control method for a distribution box with graded overheat protection as described above, comprising the following steps: S1: Temperature values ​​at each monitoring point are collected in real time by temperature sensors arranged in the distribution box; S2: Calculate the temperature change rate of each monitoring point within the preset sampling period and construct the spatial distribution matrix of the temperature rise rate; S3: Calculate the spatial dissimilarity and concentration parameters of the spatial distribution matrix of the temperature rise rate; S4: Compare the spatial difference parameter with a preset spatial difference threshold, and compare the concentration parameter with a preset concentration threshold to determine whether the current overheating mode is a balanced temperature rise mode or a local hot spot mode. S5: When the temperature rise mode is determined to be balanced, a global response strategy is executed; when the temperature rise mode is determined to be local hot spot, the temperature change rate of each monitoring point is decoupled and corrected based on the preset thermal diffusion coefficient to distinguish between primary hot spots and secondary temperature rise locations, and the branch where the primary hot spot is located is located to implement a targeted protection strategy.

[0015] Preferably, in step S5, the expression for the decoupling correction is: , Among them, v' j v is the corrected rate of temperature change at the j-th monitoring point. j Let H be the measured temperature change rate at the j-th monitoring point, H be the set of identified primary hotspots, and k be the temperature change rate at the j-th monitoring point. ij T is the thermal conductivity coefficient from the primary hotspot i to the adjacent part j. i and T j These are the current temperature values ​​of the primary hotspot i and the adjacent location j, respectively.

[0016] Preferably, the thermal conductivity k ij By analyzing the covariance matrix of the temperature rise rate of each monitoring point under independent load changes in the online learning mode during the initial commissioning of the distribution box, and adaptively calibrating it using the partial least squares regression algorithm.

[0017] Preferably, before step S2, a step of performing time-stamp-aligned sliding window synchronization compensation processing on the temperature data collected from each monitoring point is included to eliminate spatial distribution calculation errors caused by asynchronous sampling timing.

[0018] The beneficial effects of this invention are as follows: 1. This invention introduces a spatial variability parameter. When the overall ambient temperature changes or the overall load fluctuates, the temperature rise rate at each point rises and falls synchronously, and the average value changes accordingly. However, the spatial variability parameter remains stable. This allows the invention to distinguish between overall environmental changes and local abnormal changes, and it can adapt to different models and configurations of distribution boxes without complicated on-site calibration work.

[0019] 2. In the early stages of contact resistance degradation, the absolute value of the temperature rise rate at the fault point may not have exceeded the safety threshold, but its deviation from the population mean has already occurred. The spatial variability parameter, as a statistical measure characterizing spatial non-uniformity, can capture this deviation signal before the fault develops to the dangerous threshold, thereby achieving early warning, significantly advancing the response time of overheat protection, and significantly improving the sensitivity of early fault identification.

[0020] 3. This invention corrects the temperature change rate of each monitoring point based on a preset thermal diffusion coefficient, which can eliminate the influence of heat conduction from primary hot spots to adjacent parts, accurately distinguish between primary hot spots and secondary temperature rises, and precisely limit the protection action to the faulty branch. This avoids large-scale power outages caused by thermal diffusion in existing technologies, maximizes the protection of the power supply continuity of normal branches, eliminates secondary misjudgments caused by thermal diffusion coupling effects, and achieves precise targeted protection. It has important practical value for industrial production scenarios with stringent power supply reliability requirements. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0022] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 2 This is a flowchart illustrating Embodiment 2 of the present invention; In the diagram, 1. enclosure; 2. electrical components; 3. busbar; 4. multi-point temperature sensor array; 5. support frame. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0024] The following description provides specific application scenarios and requirements for this specification, intended to enable those skilled in the art to make and use the contents of this specification. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this specification. Therefore, this specification is not limited to the embodiments shown, but rather to the widest scope consistent with the claims.

[0025] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "longitudinal", "lateral", "radial", "length", "width", "thickness", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element or component to have a specific orientation, or to be constructed and operated in a specific orientation.

[0026] It should be noted that the terms "first," "second," and similar words do not indicate any order, quantity, or importance, but are only used to distinguish different components and should not be construed as limiting the embodiments of this application.

[0027] It should be noted that the terms "installation," "setup," "equipped with," "connection," and "connected" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral structures; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium, or internal connections between two devices, components, or parts.

[0028] It should be noted that the terms "in some embodiments," "exemplarily," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "in some embodiments," "exemplarily," or "for example" should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "in some embodiments," "exemplarily," and "for example" is intended to present related concepts in a specific manner, meaning that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the above terms in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0029] Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0030] Regarding the accompanying drawings of this application, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this specification. It should also be understood that the drawings are not necessarily drawn to scale.

[0031] Example 1 This embodiment provides a distribution box with graded overheat protection, such as... Figure 1 The diagram shows a housing 1 containing a busbar 3, several electrical components 2, and a terminal block. The electrical components 2 and the terminal block have several electrical connection points for fixing wires with bolts. Monitoring points are set at these electrical connection points. The bolts and wires are not shown in the diagram. The diagram also includes a multi-point temperature sensor array 4 for detecting the temperature at each monitoring point, and a control module electrically connected to the multi-point temperature sensor array 4. The control module is configured to: calculate the temperature change rate of each monitoring point based on the temperature collected within a preset sampling period, and construct a spatial distribution matrix of the temperature rise rate composed of the temperature change rates of each monitoring point; calculate the spatial difference parameter and concentration parameter of the spatial distribution matrix of the temperature rise rate, compare them with preset spatial difference thresholds and concentration thresholds, and determine whether the current overheating mode is a balanced temperature rise mode or a local hotspot mode; when determined to be a balanced temperature rise mode, execute a global response strategy; when determined to be a local hotspot mode, correct the temperature change rate of each monitoring point based on a preset thermal diffusivity coefficient to distinguish between primary hotspots and secondary temperature rise locations, and locate the branch where the primary hotspot is located to execute a targeted protection strategy.

[0032] The enclosure 1 is a conventional distribution box structure made of cold-rolled steel plate, which has good dustproof and moisture-proof performance, and provides a carrier for the installation and protection of internal electrical components 2 and terminal blocks. The electrical components 2 include commonly used components of power distribution systems such as circuit breakers and contactors, which are used to realize the functions of circuit switching and protection. The terminal blocks are made of copper material and are used to realize the circuit connection between various electrical components 2 to ensure stable current transmission. The wiring bolts are high-strength conductive bolts, which are used to firmly fix the wires to the electrical connection points to ensure connection reliability and avoid increased contact resistance due to loosening.

[0033] The multi-point temperature sensor array 4 integrates several single-point infrared temperature sensor probes. The multi-point temperature sensor array 4 is mounted on the inside of the box door (or on the inner wall of the distribution box) at a preset observation position via a bracket 5, ensuring that the single-point infrared temperature sensor probes are aligned with each monitoring point. These monitoring points include the electrical connection points of the main incoming line terminals and / or the electrical connection points of the incoming lines of each branch circuit breaker and / or the electrical connection points of the outgoing lines of each branch circuit breaker and / or the electrical connection points at the busbar 3 connections. Each infrared temperature sensor measures the surface temperature of the conductor in each monitoring area remotely at a preset sampling frequency (e.g., 1Hz) and transmits the temperature data and corresponding timestamp to the control module via a communication bus. This non-contact infrared temperature measurement method eliminates the need to attach any sensing element to the conductor surface, fundamentally avoiding interference with existing electrical connections or introducing new contact problems due to temperature sensor installation. It also eliminates the risk of short circuits caused by detached sensor leads.

[0034] As an alternative embodiment, a small number of wide-angle infrared thermal imagers or scanning sensors can be used to perform global monitoring of the distribution box, using thermal images to quickly screen for abnormal hot spots in spatial distribution. Once an abnormal area is detected, a single-point infrared sensor installed nearby (or a thermal imager adjusted to that area) is triggered to perform high-frequency, high-precision data acquisition to calculate accurate temperature rise rate and spatial difference parameters for executing subsequent protection logic.

[0035] The control module uses a microcontroller or PLC controller, with a built-in preset control program. It has the functions of data reception, calculation, judgment and instruction output, and is the core control unit of the entire overheat protection system.

[0036] In this embodiment, the control module receives real-time temperature values ​​from each sensor and calculates the temperature change rate at each monitoring point using a preset time window Δt (Δt = 10s in this embodiment). To eliminate spatial distribution calculation errors caused by slight asynchrony in the sampling timing of each sensor, the control module performs a sliding window synchronization compensation process based on timestamp alignment on the data from each monitoring point before performing the calculation. Specifically, each sensor node records a high-precision timestamp during sampling, and the control module performs a sliding window synchronization compensation process with a length of Δt.s Linear interpolation is performed on the data of each node within a small time window to uniformly align it to the reference time t. ref Obtain the equivalent synchronous temperature value T i (t ref ).

[0037] After completing the synchronization compensation, calculate the temperature change rate v at the i-th monitoring point at time t. i (t), the formula is as follows: , Among them, T i (t) represents the temperature sample value of the i-th monitoring point at time t. Calculate v for all N monitoring points. i After (t), it is assembled into an N-dimensional column vector, forming a spatial distribution matrix of the temperature rise rate. .

[0038] The control module further performs quantitative analysis on the spatial distribution matrix of the temperature rise rate. Its core involves calculating two key parameters: the spatial variability parameter σ. V and concentration parameter C V .

[0039] First, calculate the arithmetic mean μ of the temperature rise rate at N monitoring points. V : ; Furthermore, the spatial variability parameter σ is calculated. V This parameter reflects the unevenness of the temperature rise rate at each monitoring point, and is essentially the standard deviation of the temperature rise rate sequence. Because the standard deviation can sensitively capture the deviation of individual data points from the overall mean, it is particularly suitable for identifying early characteristics of local anomalies. The calculation formula is: ; Calculate the concentration parameter C V This parameter reflects the degree of deviation between the point of fastest temperature rise and other points, and is used to help confirm the significance of outliers. The calculation formula is: .

[0040] This unit will calculate σ V Spatial difference threshold ε s (In this embodiment, 0.25℃ / min is used for comparison, and C is used for comparison.) V Compared with the preset concentration threshold ε c (In this embodiment, 1.5 is used for comparison.) When σ V ≥ε s And C V ≥ε c If the temperature rise is within a certain range, it is determined that there is a local hot spot mode inside the distribution box, that is, there is a local rapid temperature rise caused by abnormal contact resistance; otherwise, it is determined to be a balanced temperature rise mode, and the temperature rise may be caused by overall overload or overall change in ambient temperature.

[0041] It should be noted here that σ V The threshold setting does not depend on the specific model of the distribution box or the absolute location of the monitoring point. Because σ V This characterizes the "non-uniformity" of the temperature rise rate distribution. Under normal operating conditions, regardless of the differences in the reference temperature rise rates at various points, the non-uniformity of the distribution is always maintained at a low level. When a point begins to accelerate its temperature rise, even if its absolute value is still lower than the normal alarm value, σ V It will also increase significantly. In the early stages of fault development, the absolute value of the temperature rise rate at the fault point does not exceed the threshold, but σ V It has already exceeded the limit, thus achieving an early warning.

[0042] Because the heat generated by local hot spots can diffuse to adjacent parts through conductors such as copper busbars, the temperature rise rate v of nearby sensors is affected. j Passive elevation. If not distinguished, nearby healthy areas may be misjudged as another hotspot, leading to an inappropriate expansion of the protection zone.

[0043] To address this issue, this embodiment introduces a thermal diffusion coupling decoupling algorithm. The control module stores a pre-calibrated N×N dimensional thermal diffusion coefficient matrix K, where element k... ij This represents the heat conduction influence factor on monitoring point j when monitoring point i is a hotspot. Regarding k... ij To obtain the temperature rise data, this embodiment employs an online adaptive calibration method: during the learning window period (e.g., 72 hours) after the initial commissioning of the distribution box, the system automatically records the temperature rise response of each monitoring point when an independent load is switched on or off. For example, when only the load current of the m-th branch undergoes a step change, the system analyzes the change in the temperature rise rate Δv of monitoring point m and its adjacent monitoring point n. m and Δv n k can be estimated using the partial least squares regression algorithm. mn ≈ Δv n / Δv m Through regression analysis under multiple different operating conditions, an accurate thermal diffusivity matrix K was established and stored in non-volatile memory.

[0044] For the identified primary hotspot set H (initially, v can be selected) i (After determining the point with the largest temperature change), the temperature change rate of the remaining monitoring points j is corrected using the following formula: , Among them, v' j v is the corrected rate of temperature change at the j-th monitoring point. j For its measured rate, T i and T jLet v' be the current temperature values ​​of hotspot i and its neighboring point j, respectively. After correction, if v' j If the temperature drops back to the normal range, it is determined to be a secondary temperature rise; if v' j If the temperature remains significantly high, it can be identified as a new primary hotspot and added to set H for iterative decoupling until all abnormal temperature rises are reasonably explained.

[0045] Based on the final results of spatial difference analysis and decoupling correction, the control module executes differentiated protection strategies. If the temperature rise mode is determined to be balanced, a global response strategy is executed; if the temperature rise mode is determined to be local hotspot, a targeted protection strategy is executed on the branch where the primary hotspot is located.

[0046] The global response strategy includes: calculating the comprehensive environmental thermal stress index based on real-time data from the internal ambient temperature sensor and the external ambient temperature sensor, and initiating forced air cooling and / or dynamically adjusting the overload protection current threshold based on the index.

[0047] In practice, an ambient temperature sensor is installed inside the distribution box to measure the air temperature T inside the box. in An external ambient temperature sensor is installed on the outside of the distribution box or inside the distribution room to measure the external ambient reference temperature T. out When the control module determines that the current temperature rise mode is balanced, it initiates a global response strategy. First, it calculates the comprehensive environmental thermal stress index S. env The calculation formula is: , Where T ref The preset internal temperature is used (e.g., 40℃). α is the absolute temperature rise weighting coefficient, β is the internal / external temperature difference weighting coefficient, and γ is the temperature rise trend weighting coefficient. This index comprehensively reflects the current degree of heat accumulation inside the chamber, the degree of deterioration in heat dissipation conditions, and the temperature change trend. Subsequently, S... env The response level is determined by comparing the response with multiple preset thresholds S1, S2, and S3: when S... env When S1 < S1, the system maintains normal operation; when S1 ≤ S env When S2 < S2, initiate a level 1 response, activating the built-in forced air cooling fan to operate at a fixed duty cycle; when S2 ≤ S env When <S3, the secondary response is initiated, the cooling fan runs at full speed, and the overload protection current threshold of the main circuit is dynamically reduced according to the preset temperature compensation curve, with the reduction amount being the same as S. env Proportional; when S envWhen the value is ≥S3, a level 3 response is initiated. Based on the level 2 response, an early warning message indicating excessive environmental thermal stress in the distribution box is sent to the monitoring platform via the communication interface. The specific implementation method for dynamically adjusting the overload protection current threshold is as follows: the control module sends a threshold adjustment command to the electronic trip unit or intelligent circuit breaker via the communication bus, or controls the reference voltage base of the traditional thermal-magnetic trip unit through analog voltage output.

[0048] The global response strategy based on the comprehensive environmental thermal stress index described above enables fine-grained grading of response measures under balanced temperature rise scenarios, avoiding the one-size-fits-all, coarse response of traditional solutions. The comprehensive environmental thermal stress index integrates information from three dimensions: the absolute temperature inside the enclosure, the temperature difference between inside and outside, and the temperature rise trend. This allows for a more comprehensive assessment of the thermal state of the distribution box, especially when high external ambient temperatures worsen heat dissipation conditions. Even if the absolute temperature inside the enclosure has not yet reached a dangerous level, the S... env The temperature will also rise due to the contribution of the internal and external temperature difference, thus prompting the implementation of heat dissipation measures in advance. Simultaneously, the dynamic adjustment of the overload protection threshold allows the triggering timing of overload protection to adaptively follow changes in environmental thermal stress. In high-temperature environments, the threshold is appropriately lowered to improve protection sensitivity, while in normal-temperature environments, the standard threshold is restored to avoid unnecessary malfunctions, achieving an optimized balance between protection performance and environmental adaptability.

[0049] When the system identifies a local hotspot mode, it indicates the presence of one or more fault points with poor contact. The control module executes a targeted protection strategy, using the sensor ID corresponding to the primary hotspot identified after decoupling to find the specific power supply branch number through a preset mapping table.

[0050] For the identified target branch, this embodiment further implements refined grading measures based on the urgency of heat accumulation. The quantitative index of urgency is the branch heat accumulation hazard level R, which is calculated using the following formula: , Among them, v' i v represents the decoupled correction for the branch's hotspot temperature rise rate. th The threshold for the dangerous rate of temperature rise; T i T represents the current temperature of this hotspot. th The hazardous temperature threshold; the integral term is the temperature exceeding the baseline value T. base The cumulative heat; w1, w2, and w3 are weighting coefficients.

[0051] Based on the R value range, the following graded measures will be implemented: First level (R<R1, warning level): The system determines that there are early signs of contact degradation in the branch circuit, but no imminent danger has formed. The implementation measures are: sending a warning message of "Local temperature rise abnormality exists in the wiring terminal of branch XX, and it is recommended to arrange planned maintenance" to the upper computer monitoring system through the communication interface, and lighting the yellow indicator light corresponding to the branch on the local human-machine interface. At this time, the power supply of the branch is not intervened.

[0052] Second level (R1≤R<R2, attention level): The system determines that the contact degradation of the branch circuit has intensified, and preventive measures need to be taken. The implementation measures are: on the basis of maintaining the warning output of the first level, the load management module performs selective load shedding on non-critical loads (such as part of lighting and socket loops) carried by the branch, so as to reduce the load current of the branch and thus slow down the temperature rise rate. If there is no load that can be shed in the branch, the power supply is maintained but the data sampling frequency is increased to 2Hz for close monitoring.

[0053] Third level (R2≤R<R3, danger level): The system determines that the branch circuit has a high overheating risk and may develop into a serious fault in a short period of time. The implementation measures are: sending a pre-warning of "The thermal accumulation risk degree of branch XX exceeds the standard, and protection tripping will be executed soon" to the monitoring platform; at the same time, checking whether the branch is a critical load branch (judged by the preset important branch mark). If it is a non-critical branch, a delay timer is started. If the R value does not fall back within the delay time, the corresponding branch shunt release is driven to perform tripping protection; if it is a critical branch, the power supply is maintained but the overload protection threshold is temporarily reduced to 80% of the rated current, and an emergency notification is sent to the operation and maintenance personnel.

[0054] Fourth level (R≥R3, emergency level): The system determines that the branch circuit is in a serious overheating state, and there is an immediate risk of insulation damage or fire. The implementation measures are: without delay, immediately drive the corresponding branch shunt release to perform tripping protection, and at the same time start the micro fire extinguishing unit in the box (if configured) to enter the trigger-ready state, and send an emergency alarm signal to the monitoring platform and the fire protection system.

[0055] During the whole process of the above hierarchical response, other branch circuits in the distribution box that are determined to be normal remain in the original power supply state, thereby maximally avoiding the occurrence of unplanned full power outage accidents.

[0056] Example 2 This embodiment provides a control method applied to a distribution box with overheating hierarchical protection, and the method runs in the control module of the distribution box described in Embodiment 1. See Figure 2 , the specific process is as follows: Step S1: Initialization and data collection. After the distribution box is powered on, the initialization and self-inspection of each sensor and execution unit are completed. The infrared temperature sensor array continuously collects the temperature value T of each monitoring point at a period of 1Hzi And the corresponding timestamp.

[0057] Step S2: Data Synchronization Preprocessing. The temperature data collected from each monitoring point undergoes timestamp-aligned sliding window synchronization compensation processing to obtain the equivalent synchronized temperature value T. i (t ref ).

[0058] Step S3: Calculate the spatial distribution matrix of the temperature rise rate. Based on... Calculate v for each monitoring point i (t), and construct the spatial distribution matrix V(t) of the temperature rise rate.

[0059] Step S4: Calculation of spatial variability and concentration. Based on... and Calculate the current σ V and C V .

[0060] Step S5: Overheating mode determination. Compare σ V With ε s (0.25℃ / min), C V With ε c (1.5). If the threshold conditions are met simultaneously, it is determined to be a local hotspot mode. Based on the preset thermal diffusion coefficient, the temperature change rate of each monitoring point is decoupled and corrected to distinguish between primary hotspots and secondary temperature rise locations, and the branch where the primary hotspot is located is located and targeted protection strategy is implemented for it; otherwise, it is determined to be a balanced temperature rise mode and a global response strategy is implemented.

[0061] Step S6: Loop and Return. After completing one protection decision cycle, the system returns to step S1 to continue monitoring for the next cycle.

[0062] In the local hotspot mode, the thermal diffusion coupling decoupling unit is based on The temperature rise rate at each monitoring point is decoupled and corrected to eliminate thermal diffusion interference. Based on the decoupling correction results, the primary hot spot set H is accurately identified, and the corresponding power distribution branch number of each hot spot sensor is found through a preset mapping table. Corresponding measures such as early warning, load reduction, or circuit breaker tripping are taken for the identified target branches. In the balanced temperature rise mode, a global response strategy is executed (initiating heat dissipation and dynamically adjusting the overload threshold).

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A distribution box with graded overheat protection, comprising a box body, wherein a busbar, a plurality of electrical components, and a terminal block are disposed within the box body, and the electrical components and the terminal block are provided with a plurality of electrical connection points for fixing wires with terminal bolts, characterized in that, Monitoring points are set up for electrical connection points, and the system also includes a multi-point temperature sensor array for temperature detection at each monitoring point, and a control module electrically connected to the multi-point temperature sensor array. The control module is configured as follows: The temperature change rate of each monitoring point is calculated based on the temperature collected at each monitoring point within a preset sampling period, and a spatial distribution matrix of temperature rise rate composed of the temperature change rates of each monitoring point is constructed. Calculate the spatial difference and concentration parameters of the spatial distribution matrix of the temperature rise rate, compare them with the preset spatial difference and concentration thresholds, and determine whether the current overheating mode is an equilibrium temperature rise mode or a local hot spot mode. When the temperature rise mode is determined to be balanced, a global response strategy is executed. When the local hotspot pattern is determined, the temperature change rate of each monitoring point is corrected based on the preset thermal diffusion coefficient to distinguish between primary hotspots and secondary temperature rise locations, and to locate the branch where the primary hotspot is located and implement a targeted protection strategy. The spatial variability parameter is obtained by calculating the standard deviation of the spatial distribution matrix of the temperature rise rate, and the concentration parameter is obtained by calculating the ratio of the maximum temperature rise rate to the mean.

2. A distribution box with graded overheat protection according to claim 1, characterized in that, The monitoring points are located at electrical connection points of the main incoming line terminals and / or electrical connection points of the incoming terminals of each branch circuit breaker and / or electrical connection points of the outgoing terminals of each branch circuit breaker and / or electrical connection points of the busbar connections.

3. A distribution box with graded overheat protection according to claim 1, characterized in that, The global response strategy includes calculating the comprehensive environmental thermal stress index S based on the internal and external temperatures of the enclosure. env Based on this index, forced air cooling is initiated and / or the overload protection current threshold is dynamically adjusted.

4. A distribution box with graded overheat protection according to claim 3, characterized in that, S env The response level is determined by comparing the response with multiple preset thresholds S1, S2, and S3: when S... env When S1 < S1, the system maintains normal operation; when S1 ≤ S env When S2 < S2, initiate a level 1 response, activating the built-in forced air cooling fan to operate at a fixed duty cycle; when S2 ≤ S env When <S3, the secondary response is initiated, the cooling fan runs at full speed, and the overload protection current threshold of the main circuit is dynamically reduced according to the preset temperature compensation curve, with the reduction amount being the same as S. env Proportional; when S env When the value is ≥S3, a Level 3 response is initiated. Based on the Level 2 response, an early warning message indicating excessive environmental thermal stress in the distribution box is sent to the monitoring platform via the communication interface.

5. A distribution box with graded overheat protection according to claim 1, characterized in that, The targeted protection strategy includes implementing tiered measures based on the urgency of heat accumulation.

6. A control method applied to a distribution box with graded overheat protection as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Temperature values ​​at each monitoring point are collected in real time by temperature sensors arranged in the distribution box; S2: Calculate the temperature change rate of each monitoring point within the preset sampling period and construct the spatial distribution matrix of the temperature rise rate; S3: Calculate the spatial dissimilarity and concentration parameters of the spatial distribution matrix of the temperature rise rate; S4: Compare the spatial difference parameter with a preset spatial difference threshold, and compare the concentration parameter with a preset concentration threshold to determine whether the current overheating mode is a balanced temperature rise mode or a local hot spot mode. S5: When the temperature rise mode is determined to be balanced, a global response strategy is executed; when the temperature rise mode is determined to be local hot spot, the temperature change rate of each monitoring point is decoupled and corrected based on the preset thermal diffusion coefficient to distinguish between primary hot spots and secondary temperature rise locations, and the branch where the primary hot spot is located is located to implement a targeted protection strategy.

7. The control method for a distribution box with graded overheat protection according to claim 6, characterized in that, In step S5, the expression for the decoupling correction is: ， Among them, v' j v is the corrected rate of temperature change at the j-th monitoring point. j Let H be the measured temperature change rate at the j-th monitoring point, H be the set of identified primary hotspots, and k be the temperature change rate at the j-th monitoring point. ij T is the thermal conductivity coefficient from the primary hotspot i to the adjacent part j. i and T j These are the current temperature values ​​of the primary hotspot i and the adjacent location j, respectively.

8. A control method for a distribution box with graded overheat protection according to claim 7, characterized in that, The thermal conductivity coefficient k ij By analyzing the covariance matrix of the temperature rise rate of each monitoring point under independent load changes in the online learning mode during the initial commissioning of the distribution box, and adaptively calibrating it using the partial least squares regression algorithm.

9. A control method for a distribution box with graded overheat protection according to claim 6, characterized in that, Before step S2, there is also a step of performing time-stamp-aligned sliding window synchronization compensation processing on the temperature data collected from each monitoring point to eliminate spatial distribution calculation errors caused by asynchronous sampling time.

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