A power distribution network operation state multi-dimensional analysis and management and control method

Abstract

The application provides a power distribution network operation state multi-dimensional analysis and management and control method, comprising: obtaining external surface temperature distribution data from each area of a switch cabinet wall, obtaining airflow flow rate and flow direction information from a bus gap, simultaneously collecting temperature window inner wall and outer wall temperature data, and obtaining real-time airflow field distribution characteristics; evaluating the chimney effect strength level of a three-phase bus vertical arrangement area according to the real-time airflow field distribution characteristics, and determining the thermal superposition interference area range affected by the chimney effect in combination with the temperature window inner wall temperature data; performing sliding regression fitting on the accurate joint temperature estimation value according to a time window, and generating an overheating point positioning alarm signal when the change rate of the temperature abnormal rise trend exceeds a preset safety upper limit in a plurality of continuous sampling periods.

Description

Technical Field

[0001] This invention relates to the field of information technology, and in particular to a method for multi-dimensional analysis and control of the operation status of power distribution networks. Background Technology

[0002] In the operation of power distribution networks, ensuring the safe and stable operation of equipment is crucial, especially in critical equipment such as switchgear. Abnormal temperatures are often a precursor to faults, directly impacting the reliability of the power grid and the safety of users' electricity consumption. Timely and accurate monitoring of heat source temperatures within the switchgear not only prevents faults caused by overheating but also provides vital information for operation and maintenance. Research and practice in this area have undeniable value in improving the overall efficiency of the power system. However, current methods for switchgear temperature monitoring often struggle to cope with interference from complex operating environments. Many solutions neglect the influence of airflow within the switchgear on temperature distribution, leading to significant deviations between measured temperatures and actual heat source temperatures. Particularly during equipment operation, the flow of hot air within the switchgear alters the temperature field distribution, making surface temperatures unable to accurately reflect the true condition of internal heat sources. This problem is particularly pronounced under high-load operating scenarios. Furthermore, the heat generated by heat sources within the switchgear drives air upwards, forming specific airflow paths. This airflow can superimpose heat from different heat sources, interfering with the accuracy of temperature measurement points. Especially in scenarios where three-phase buses are vertically arranged and closely spaced, the rising hot air from the middle phase carries heat from other phases, affecting the temperature reading at the measuring window. This causes the displayed temperature to be influenced by non-target heat sources rather than the target heat source. This interference causes a deviation between the externally measured temperature and the actual internal heat source temperature, potentially underestimating the overheating risk of critical components. Specifically, in actual operation, suppose a switchgear's three-phase busbars are running and the temperature at the connection point of the middle phase abnormally rises. However, because the rising airflow carries heat from other phases to the measuring window, the measured temperature is incorrectly inflated. Maintenance personnel might mistakenly believe that a heat source near the window is overheating, ignoring the true risk at the middle phase connection point. This temperature misjudgment due to airflow interference not only increases the difficulty of troubleshooting but may also delay addressing critical hidden dangers. Therefore, accurately distinguishing the heat contribution of target and non-target heat sources in complex airflow environments and eliminating the interference of airflow superposition on the measuring window reading has become a key issue in ensuring the accuracy of switchgear temperature monitoring and the safe operation of equipment. Summary of the Invention

[0003] This invention provides a method for multi-dimensional analysis and control of the operating status of a power distribution network, mainly including: The temperature distribution data of the outer surface of the switch cabinet wall is obtained from various areas of the switch cabinet wall. The airflow velocity and direction information are obtained from the gap of the busbar. At the same time, the temperature data of the inner and outer walls of the temperature measurement window are collected to obtain the real-time airflow field distribution characteristics. The intensity level of the chimney effect in the vertically arranged area of ​​the three-phase busbars is evaluated based on the real-time airflow field distribution characteristics, and the range of the thermal superposition interference area affected by the chimney effect is determined by combining the temperature data of the inner wall of the temperature measurement window. The temperature difference sequence between the inner and outer walls of the temperature measurement window is extracted from the area of ​​thermal superposition interference. The airflow velocity and direction data are fused together and the temperature difference sequence is adjusted point by point according to the location of each collection point in the airflow channel and the degree of wind speed attenuation to obtain the corrected temperature difference compensation amount. By using the corrected temperature difference compensation amount to deduct the additional temperature rise component superimposed by the chimney effect at the temperature measurement window one by one, the true temperature rise data of each heat source in the cabinet is restored and conducted outward through the cabinet wall. Abnormal temperature rise heat sources that exceed the static thermal resistance network calibration value are identified, and the coordinates of potential hot spots are determined. Based on the coordinates of potential hot spots and the heat conduction paths of the three-phase busbars and conductors inside the cabinet, the proportion of heat contribution from non-target heat sources transferred to the temperature measurement window along the airflow channel is identified. The extent of the underestimation of the joint temperature caused by this proportion is assessed. The temperature inversion results of each potential hot spot are updated in combination with the airflow velocity to obtain an accurate estimate of the joint temperature. The accurate estimated joint temperature is fitted by sliding regression over a time window. When the rate of change of the abnormal temperature rise exceeds the preset safety limit in multiple consecutive sampling periods, an overheating alarm signal is generated.

[0004] Furthermore, external surface temperature distribution data are obtained from various areas of the switchgear wall, airflow velocity and direction information are obtained from the busbar gaps, and temperature data of the inner and outer walls of the temperature measurement window are collected simultaneously to obtain real-time airflow field distribution characteristics, including: Temperature probes are deployed in the top, middle, and bottom areas of the switchgear wall to obtain the outer surface temperature values ​​from each wall section. The outer surface temperature values ​​are mapped to the corresponding grid nodes according to the spatial coordinates of each temperature probe. The main direction of heat transfer is determined based on the temperature difference between adjacent grid nodes. Airflow velocity probes are deployed in the gaps between the three-phase buses in the vertically arranged area corresponding to this main direction to collect the airflow velocity and airflow direction angle within the gaps, thus obtaining the airflow motion parameters of the gaps. The airflow velocity probes are used to simultaneously collect the inner and outer wall temperatures of the temperature measurement window. The temperature difference gradient value of the window is obtained by subtracting the outer wall temperature from the inner wall temperature. Combined with the airflow direction angle and airflow velocity values ​​in the airflow motion parameters of the gaps, the spatial direction of the airflow channel through the temperature measurement window area is determined, thus obtaining the real-time airflow field distribution characteristics.

[0005] Furthermore, the step of assessing the chimney effect intensity level in the vertically aligned region of the three-phase busbars based on real-time airflow field distribution characteristics, and determining the range of the thermal superposition interference region affected by the chimney effect by combining the temperature data of the inner wall of the temperature measurement window, includes: Based on the airflow velocity and airflow direction angle in the real-time airflow field distribution characteristics, the upward velocity of the airflow in the gaps between each busbar within the vertically arranged three-phase busbar region is compared. If the upward velocity exceeds a preset velocity threshold, a chimney effect is determined to exist in the vertically arranged region. The chimney effect intensity is classified into low, medium, and high levels based on the ratio of the upward velocity to the velocity threshold. The inner wall temperature data of the temperature measurement window is processed using a thermal superposition interference identification method based on the chimney effect intensity level. This method involves moving a fixed-duration sliding window along the time axis segment by segment, capturing the inner wall temperature data for the corresponding time period at each window position, and extracting the maximum temperature value from each segment of the inner wall temperature data. The difference between the minimum temperature values ​​is used as the temperature fluctuation amplitude to obtain the inner wall temperature fluctuation characteristic sequence. The inner wall temperature fluctuation characteristic sequence is compared with the chimney effect intensity level. If the temperature fluctuation amplitude increases synchronously with the increase of the chimney effect intensity level, it is determined that there is thermal superposition interference at the temperature measurement window. The spatial coordinates of the temperature measurement window are marked as thermal superposition interference points. The determination results of each temperature measurement window are summarized to obtain a set of thermal superposition interference points. According to the spatial coordinates of each interference point in the set of thermal superposition interference points, the entire temperature measurement window area covered by the extended path is defined as the thermal superposition interference area affected by the chimney effect, extending upward to the top area of ​​the cabinet wall and downward to the bottom area of ​​the cabinet wall along the vertical arrangement direction of the three-phase busbar.

[0006] Furthermore, the step of extracting the temperature difference sequence of the inner and outer walls of the temperature measurement window from the thermal superposition interference area, and then adjusting the temperature difference sequence point by point according to the location of each collection point in the airflow channel and the degree of wind speed attenuation, by fusing airflow velocity and direction data, yields the corrected temperature difference compensation amount, including: The spatial coordinates of each temperature measuring window are located within the thermal interference area. For each window, the inner and outer wall temperatures are simultaneously read. The difference between the inner and outer wall temperatures is obtained by subtracting the outer wall temperature from the inner wall temperature. All single-point temperature difference values ​​are then arranged into a sequence of inner and outer wall temperature differences according to the arrangement of the temperature measuring windows on the cabinet wall. Based on the airflow direction angle in the real-time airflow field distribution characteristics, the airflow channel position of each temperature measuring window within the thermal interference area is determined. If the temperature measuring window is located in the lower region where the airflow enters the cabinet, it is marked as the channel inlet section; if it is located in the middle region where the airflow rises, it is marked as the channel middle section. The area above the airflow outlet is marked as the channel outlet section, and the airflow channel location labels of each collection point are obtained. The wind speed attenuation degree at each collection point is determined according to the airflow channel location labels and the airflow velocity value. An increasing attenuation coefficient is set according to the wind speed attenuation degree from low to high. The attenuation coefficient is multiplied point by point by the single-point temperature difference value at the corresponding position in the temperature difference sequence to obtain the attenuated temperature difference value. The attenuated temperature difference value is used to replace the original single-point temperature difference value at the corresponding temperature measurement window position in the temperature difference sequence. All temperature measurement windows within the thermal superposition interference area are traversed to complete the point-by-point replacement, and the corrected temperature difference compensation amount is obtained.

[0007] Furthermore, the modified temperature difference compensation is used to subtract the additional temperature rise component at the temperature measurement window due to the chimney effect, restoring the true temperature rise data of each heat source in the cabinet conducted outward through the cabinet wall, identifying abnormal temperature rise heat sources exceeding the static thermal resistance network calibration value, and determining the coordinates of potential hot spots, including: The corrected temperature difference compensation is used to subtract the inner wall temperature values ​​of each temperature measuring window within the thermal superposition interference area. The temperature difference compensation at the corresponding position is subtracted from the inner wall temperature value to obtain the actual temperature rise data conducted outward through the cabinet wall at each temperature measuring window. The actual temperature rise data is compared with the pre-calibrated temperature rise benchmark value. If the actual temperature rise data exceeds the temperature rise benchmark value at the corresponding position and the exceedance is greater than the preset temperature rise deviation threshold, the heat source inside the cabinet corresponding to the temperature measuring window is determined to be an abnormal temperature rise heat source. Based on the spatial coordinates of the temperature measuring window corresponding to the abnormal temperature rise heat source, the grid node where the temperature measuring window is located is located. According to the preset correspondence between the grid node of the cabinet wall and the spatial position of the three-phase bus inside the cabinet, the cabinet wall coordinates of the grid node are mapped to the spatial coordinates of the bus area inside the cabinet. The mapping results of all abnormal temperature rise heat sources are summarized to determine the coordinates of the potential hot spot.

[0008] Furthermore, based on the coordinates of potential hot spots and the heat conduction paths of the three-phase busbars and conductors within the cabinet, the proportion of heat contribution from non-target heat sources transferred along the airflow channel to the temperature measurement window is identified. The extent of the underestimation of the joint temperature caused by this proportion is assessed. Combined with the airflow velocity, the temperature inversion results of each potential hot spot are updated to obtain an accurate estimate of the joint temperature, including: Based on the location of the potential hot spot coordinates within the three-phase busbar space inside the cabinet, the heat conduction path between the hot spot and adjacent busbar joints and conductors inside the cabinet is traced along the physical connection direction of the three-phase busbars. Other heat-generating components located upstream of the heat conduction path, whose heat is transferred via airflow channels to the temperature measurement window near the potential hot spot, are identified. These other heat-generating components are marked as non-target heat sources, thus obtaining a set of non-target heat source locations. Based on the airflow channel connectivity between each non-target heat source in the set of non-target heat source locations and the current hot spot, the airflow velocity gradually decreases with increasing transmission distance. The attenuation characteristics are used to determine the proportion of heat contribution transferred by each non-target heat source to the temperature measurement window corresponding to the overheating point. The heat contribution proportion is used to evaluate the underestimation of the joint temperature caused by the current overheating point receiving superimposed heat from non-target heat sources. The actual temperature rise data at the temperature measurement window corresponding to the current overheating point is added to the underestimation to obtain the temperature inversion result of the overheating point. The heat contribution proportion is updated in combination with the dynamic changes in airflow velocity. The underestimation of each potential overheating point is recalculated based on the updated heat contribution proportion, and the temperature inversion result is corrected to obtain the accurate joint temperature estimate.

[0009] Furthermore, a sliding regression fitting is performed on the accurate estimated joint temperature over a time window. When the rate of change of the abnormal temperature rise trend exceeds the preset safety limit within multiple consecutive sampling periods, an overheating alarm signal is generated, including: The precise estimated joint temperature is segmented into time series using a sliding time window. Within each window, a linear regression is performed on the estimated joint temperature. The slope of the temperature change is extracted from the fitting result as the rate of change of the abnormal temperature rise trend within that window. The rate of change is compared window by window with a preset safety upper limit. The number of consecutive windows where the rate of change exceeds the preset safety upper limit is counted. If the number of consecutive windows reaches a preset periodic threshold, an overheating hotspot location alarm signal is generated for the potential overheating hotspot.

[0010] Furthermore, the method also includes: based on the hot spot location alarm signal and the operating load and topology of the feeder where the switch cabinet is located, identifying feeder segments and equipment that may be affected by heat, outputting the location of the hot spot, estimated joint temperature, and risk level of the affected area, and generating an operation and maintenance solution.

[0011] Furthermore, based on the hot spot location alarm signal and the operating load and topology of the feeder where the switchgear is located, feeder sections and equipment that may be affected by heat are identified, and the location of the hot spot, estimated joint temperature, and risk level of the affected area are output. An operation and maintenance response plan is then generated, including: Obtain the current operating load data and feeder topology information of the feeder corresponding to the switchgear where the potential hot spot is located. The topology information includes the electrical connection relationship between the feeder and adjacent feeders and the installation position of the switchgear in the feeder. Based on the topology information along the physical connection direction of the three-phase busbar and the spatial arrangement relationship of adjacent cabinets, trace the transmission path of the overheating risk from the current hot spot to the upstream and downstream, identify the feeder segments and cabinet equipment located on the transmission path that have an electrical connection or thermal conduction association with the current hot spot, and obtain the set of affected feeder segments and the list of affected equipment. Based on the set of affected feeder segments and the list of affected equipment, combined with the operating load data of each feeder segment and the accurate joint temperature estimate, output the coordinates of the hot spot location, the estimated joint temperature, the set of affected feeder segments, the list of affected equipment, and the risk level of each area, and generate an operation and maintenance handling plan that includes maintenance priority ranking and load transfer suggestions.

[0012] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects: This invention discloses a multi-dimensional analysis and control method for the operation status of a power distribution network. It addresses unique business scenario problems such as thermal superposition interference, temperature underestimation, and overheating risk spread caused by the chimney effect in the vertically arranged area of ​​three-phase busbars in switchgear. This method integrates the logical connection of real-time airflow distribution assessment, heat conduction path identification, and fault operation and maintenance handling, namely, how to accurately restore the true temperature rise of heat sources in the cabinet, estimate the joint temperature, and prevent the spread of risks. This invention acquires external surface temperature distribution, airflow information, and temperature difference data between the inner and outer walls of the measurement window using a multi-point temperature acquisition module and airflow velocity probe. Based on real-time airflow field distribution characteristics, it assesses the intensity level of the chimney effect. A thermal superposition interference identification algorithm processes the inner wall temperature data to determine the interference area range. Temperature difference sequences are extracted and fused with airflow data to obtain a corrected temperature difference compensation amount, thereby deducting additional temperature rise components, restoring the true temperature rise data, identifying abnormal heat sources and potential overheating hotspot coordinates, and further evaluating the contribution ratio of non-target heat sources based on heat conduction paths. The temperature inversion results are updated to obtain accurate joint temperature estimates. A sliding regression fitting analysis is performed to analyze temperature anomaly trends, generating overheating hotspot location alarm signals. Based on feeder load and topology analysis, the risk diffusion path is analyzed, outputting the overheating hotspot location, temperature estimate, risk level of the affected area, and operation and maintenance handling plan. Overall, this invention achieves accurate monitoring and intelligent control of overheating faults in switchgear busbar joints, improving the safety and reliability of power distribution network operation. Attached Figure Description

[0013] Figure 1 This is a flowchart of a method for multi-dimensional analysis and control of power distribution network operation status according to the present invention.

[0014] Figure 2 This is a schematic diagram of a multi-dimensional analysis and control method for the operation status of a power distribution network according to the present invention.

[0015] Figure 3 This is another schematic diagram of a multi-dimensional analysis and control method for the operation status of a power distribution network according to the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and thoroughly described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of the present invention.

[0017] like Figures 1-3 This embodiment of a multi-dimensional analysis and control method for the operation status of a power distribution network may specifically include: Step S101: Obtain the outer surface temperature distribution data from each area of ​​the switch cabinet wall, obtain the airflow velocity and direction information from the bus gap, and simultaneously collect the temperature data of the inner and outer walls of the temperature measurement window to obtain the real-time airflow field distribution characteristics.

[0018] Temperature probes are deployed in the top, middle, and bottom areas of the switchgear wall using a multi-point temperature acquisition module. The outer surface temperature values ​​are obtained from each wall section. These values ​​are then mapped to corresponding grid nodes according to the spatial coordinates of each probe, forming a temperature distribution matrix for the switchgear wall's outer surface. The main direction of heat transfer is determined based on the temperature difference between adjacent grid nodes in the matrix. At the gaps between the three-phase buses in the vertically aligned area corresponding to this main direction, probes from a pre-arranged airflow velocity probe array are activated and used to collect the airflow velocity and direction angle within each gap, obtaining the airflow motion parameters of the gaps. The airflow velocity probes simultaneously acquire the inner and outer wall temperatures of the temperature measurement window. The temperature difference gradient is obtained by subtracting the outer wall temperature from the inner wall temperature. Combined with the airflow direction angle and velocity values ​​from the airflow motion parameters of the gaps, along with the temperature distribution matrix and main direction information of the switchgear wall's outer surface, the spatial direction of the airflow channel traversing the temperature measurement window area is determined, yielding real-time airflow field distribution characteristics.

[0019] In the specific implementation of switchgear temperature monitoring, the arrangement of multi-point temperature acquisition modules follows the principle of cabinet wall space zoning.

[0020] For example, the switch cabinet wall is vertically divided into a top area, a middle area, and a bottom area, and several temperature probes are installed in each area at preset intervals. The temperature probes in the top area mainly cover the heat dissipation surface on the top of the cabinet and the vicinity of the upper busbar outlet, the temperature probes in the middle area correspond to the height of the three-phase busbar body, and the temperature probes in the bottom area are arranged around the air inlet at the bottom of the cabinet.

[0021] In one possible implementation, each temperature probe records its spatial coordinates during installation, including its lateral and longitudinal positions within the cabinet wall plane. The temperature distribution matrix is ​​formed as follows: the outer surface of the cabinet wall is virtually divided into several grid cells, each corresponding to a grid node. The temperature values ​​collected by each temperature probe are mapped to the nearest grid node according to the probe's spatial coordinates, thus forming a temperature distribution matrix for the outer surface of the cabinet wall, indexed by grid nodes and containing temperature values. This matrix visually reflects the temperature distribution across different areas of the cabinet wall.

[0022] Specifically, the primary direction of heat transfer is determined based on the temperature difference between adjacent grid nodes. When the temperature of a grid node is higher than that of its adjacent grid nodes, heat is transferred in the direction of decreasing temperature. By traversing each pair of adjacent grid nodes in the temperature distribution matrix of the outer surface of the cabinet wall, the temperature difference of each pair of nodes is calculated, and each direction is represented as a vector, for example, the upward direction is (0,1), the downward direction is (0,-1), the left direction is (-1,0), and the right direction is (1,0). Then, all vectors are weighted and averaged, with the weighting coefficient being the corresponding temperature difference. The direction of the resulting average vector is the primary direction of heat transfer. In switchgear with three-phase busbars arranged vertically, the primary direction of heat transfer usually points to the upper part of the cabinet, corresponding to the natural convection path formed by the rising hot air inside the cabinet.

[0023] It should be noted that the airflow velocity probe is positioned at the bus gap corresponding to the main direction of heat transfer. The bus gap refers to the empty area between two adjacent phase buses, which is the main channel for the rising of hot air inside the cabinet. The airflow velocity probe simultaneously collects the airflow velocity value and the airflow direction angle. The airflow velocity value reflects the speed of airflow, and the airflow direction angle reflects the spatial orientation of airflow. Together, they constitute the airflow motion parameters of the bus gap.

[0024] In one embodiment, the inner and outer wall temperatures of the temperature measuring window are simultaneously acquired by the airflow velocity probe or a separate window temperature sensor. The window temperature gradient is obtained by subtracting the outer wall temperature from the inner wall temperature, and this value characterizes the intensity of heat passing through the window wall. Combined with the airflow direction angle in the airflow motion parameters of the busbar gap, it is determined whether the airflow channel passes through the temperature measuring window area; combined with the airflow velocity value, the ability of the airflow to carry heat through this area is evaluated. This determines the spatial orientation of the airflow channel through the temperature measuring window area, forming a real-time airflow field distribution characteristic that describes the flow path of the airflow within the cabinet and its spatial relationship with the temperature measuring window.

[0025] Step S102: Evaluate the chimney effect intensity level in the vertically arranged area of ​​the three-phase busbars based on the real-time airflow field distribution characteristics, and determine the range of the thermal superposition interference area affected by the chimney effect by combining the temperature data of the inner wall of the temperature measurement window.

[0026] Based on the airflow velocity and direction angle in the real-time airflow field distribution characteristics, the rising velocity of the airflow in the gaps between each busbar within the vertically arranged three-phase busbar region is compared. The chimney effect intensity is classified into low, medium, and high levels based on the ratio *r* of the rising velocity to a preset velocity threshold of 0.5 m / s. Where *r* < 1 indicates a low level, 1 ≤ *r* < 2 indicates a medium level, and *r* ≥ 2 indicates a high level. If *r* ≥ 1, a chimney effect is determined to exist in the vertically arranged region. The inner wall temperature data of the temperature measurement window is processed using a thermal superposition interference identification method based on the chimney effect intensity level. This method involves moving a fixed-duration sliding window along the time axis segment by segment, capturing the inner wall temperature data for the corresponding time period at each window position. The difference between the maximum and minimum temperature values ​​in each segment of inner wall temperature data is extracted as the temperature fluctuation amplitude, obtaining the inner wall temperature fluctuation characteristic sequence. The temperature fluctuation characteristic sequence of the inner wall is correlated and compared with the chimney effect intensity level. If the temperature fluctuation amplitude increases synchronously with the increase of the chimney effect intensity level, it is determined that there is thermal superposition interference at the temperature measurement window. The spatial coordinates of the temperature measurement window are marked as thermal superposition interference points. The determination results of each temperature measurement window are summarized to obtain a set of thermal superposition interference points. Based on the spatial coordinates of each interference point in the set of thermal superposition interference points, the entire temperature measurement window area covered by the extended path is defined as the thermal superposition interference area affected by the chimney effect, extending upwards to the top area of ​​the cabinet wall and downwards to the bottom area of ​​the cabinet wall along the vertical arrangement direction of the three-phase busbar.

[0027] In the specific implementation of switchgear temperature monitoring, the chimney effect refers to the natural convection phenomenon formed by the vertical rise of hot air inside the cabinet due to its decreased density. When the three-phase busbars are arranged vertically, the heat generated by each phase busbar heats the surrounding air, and the hot air flows upward along the gaps between the busbars, forming an airflow channel similar to the inside of a chimney. This airflow carries the heat generated by the heat source below to the upper area, causing the heat from different heat sources to overlap spatially.

[0028] For example, the assessment of the chimney effect intensity level is based on the airflow velocity values ​​in the real-time airflow field distribution characteristics.

[0029] In one embodiment, the preset flow velocity threshold is determined based on the structural dimensions of the switchgear and the width of the busbar gap. When the upward velocity of the airflow in the busbar gap does not exceed the flow velocity threshold, the chimney effect intensity is determined to be low, at which point the airflow has little interference with the temperature distribution. When the upward velocity of the airflow exceeds the flow velocity threshold but does not reach twice the flow velocity threshold, it is determined to be medium. When the upward velocity of the airflow reaches or exceeds twice the flow velocity threshold, it is determined to be high, at which point the heat superposition interference is significant.

[0030] It should be noted that the purpose of the thermal superposition interference identification method is to identify abnormal temperature fluctuations affected by the chimney effect from the inner wall temperature data of the temperature measurement window. This method uses a sliding window approach to segment the time series data. The specific process is as follows: A window of fixed duration is set, which is determined based on the thermal response characteristics of the switchgear. The window starts from the beginning of the temperature data sequence and moves forward by a preset step along the time axis each time, capturing all the inner wall temperature samples within that time period at each window position. For each segment of temperature data, the maximum and minimum temperature values ​​are extracted, and the difference between the two is taken as the temperature fluctuation amplitude for that time period. As the window moves segment by segment and completes the traversal of all data, a set of temperature fluctuation amplitude values ​​arranged by time is obtained, i.e., the inner wall temperature fluctuation characteristic sequence.

[0031] In one possible implementation, the duration of the sliding window is set to match the periodic fluctuations of airflow within the switchgear. When a chimney effect exists within the cabinet, the upward flow of hot air is not constant but rather exhibits periodic variations in intensity due to factors such as changes in the ambient temperature outside the cabinet and load fluctuations. The window duration covers at least one complete airflow fluctuation cycle, thereby enabling the extracted temperature fluctuation amplitude to reflect the temperature change characteristics caused by the chimney effect.

[0032] Specifically, the correlation between the inner wall temperature fluctuation characteristic sequence and the chimney effect intensity level follows this logic: the temperature fluctuation amplitudes obtained at different time periods are grouped according to the chimney effect intensity level at the corresponding time, and the changing trend of the temperature fluctuation amplitudes in each group is observed. If the temperature fluctuation amplitude shows a synchronous increasing trend as the chimney effect intensity level rises from low to medium and then to high, it indicates that there is a positive correlation between the temperature fluctuation and the chimney effect at this temperature measurement window, and thus it is determined that there is thermal superposition interference at this location.

[0033] It is understandable that the essence of thermal superposition interference is that heat generated by a non-target heat source is transferred to the temperature measurement window area by the airflow and superimposed on the temperature reading of the target heat source. When the chimney effect intensifies, the airflow's ability to carry heat increases, resulting in more superimposed heat received at the temperature measurement window, and consequently, a greater fluctuation in the inner wall temperature. Conversely, when the chimney effect weakens, the superimposed heat decreases, and the fluctuation amplitude decreases accordingly. This synchronous change relationship is the basis for determining the existence of thermal superposition interference.

[0034] Preferably, for temperature measuring windows identified as having thermal superposition interference, their spatial coordinates on the switchgear wall are recorded, including the window's height relative to the bottom of the cabinet and its horizontal position relative to the side of the cabinet. These coordinates are marked as thermal superposition interference points. After traversing all temperature measuring windows within the switchgear and completing the above determination process, all marked interference points are summarized to form a thermal superposition interference point set. Further, the delineation of the thermal superposition interference area is based on the spatial distribution of each point in the interference point set. Along the direction perpendicular to the three-phase busbars, the path extends upwards from the coordinate position of each interference point to the boundary of the top area of ​​the cabinet wall, and downwards to the boundary of the bottom area of ​​the cabinet wall. All temperature measuring windows traversed by the extension path are included in the interference area. When the extension paths of multiple interference points overlap, the union of the paths is taken as the thermal superposition interference area. The determination of this area provides a spatial positioning basis for subsequent temperature compensation processing, clarifying the distribution of temperature measuring windows that are affected by the chimney effect, leading to temperature reading distortion.

[0035] Step S103: Extract the temperature difference sequence of the inner and outer walls of the temperature measurement window from the thermal superposition interference area, and adjust the temperature difference sequence point by point according to the location of the airflow channel and the degree of wind speed attenuation of each collection point by fusing the airflow velocity and direction data to obtain the corrected temperature difference compensation amount.

[0036] The spatial coordinates of each temperature measuring window are located within the thermal interference area. For each window, the inner and outer wall temperatures are simultaneously read. The difference between the inner and outer wall temperatures is calculated to obtain a single-point temperature difference. These single-point temperature differences are then arranged into a sequence based on the window's arrangement on the cabinet wall. The airflow direction angle in the real-time airflow field distribution is used to determine the airflow channel location of each temperature measuring window within the thermal interference area. If the window is located in the lower part of the cabinet where air enters, it is marked as the channel inlet; if in the middle part where air rises, it is marked as the channel middle section; and if in the upper part where air flows out, it is marked as the channel outlet. This provides the airflow channel location label for each data collection point. The degree of wind speed attenuation at each sampling point is determined based on the airflow channel location labels and airflow velocity values. The wind speed attenuation is low at the channel inlet section because the airflow has just entered the cabinet; medium attenuation is due to the airflow being blocked by the busbar; and high attenuation is due to airflow diffusion at the channel outlet section. An increasing attenuation coefficient is set according to the degree of wind speed attenuation from low to high. This attenuation coefficient is then multiplied point-by-point by the corresponding single-point temperature difference value in the temperature difference sequence to obtain the attenuated temperature difference value. The attenuated temperature difference value is then used to replace the original single-point temperature difference value at the corresponding temperature measurement window position in the temperature difference sequence. This point-by-point replacement is performed across all temperature measurement windows within the thermal superposition interference area to obtain the corrected temperature difference compensation amount.

[0037] In the specific implementation of switchgear temperature monitoring, extracting the temperature difference sequence between the inner and outer walls of the temperature measuring window is fundamental to temperature compensation. Each temperature measuring window within the thermal superposition interference area is equipped with an inner wall temperature sensor and an outer wall temperature sensor, which are respectively attached to the inner and outer surfaces of the measuring window. At the same sampling time, the inner and outer wall temperature values ​​of each measuring window are simultaneously read, and the single-point temperature difference value at that window location is obtained by subtraction. This value reflects the intensity of heat passing through the wall of the temperature measuring window.

[0038] For example, when the thermal interference area contains several temperature measuring windows, the temperature difference values ​​of all single points are arranged sequentially according to the spatial arrangement of the windows on the cabinet wall from bottom to top or from left to right to form a temperature difference sequence of the inner and outer walls of the temperature measuring windows. Each element of this sequence corresponds to the temperature difference state of a temperature measuring window, and the length of the sequence is consistent with the number of temperature measuring windows in the interference area.

[0039] It is important to note that determining the location of the airflow channel is a crucial step in temperature difference compensation. In a switchgear with vertically arranged three-phase busbars, hot air rises along the gaps between the busbars, forming an airflow channel with distinct spatial segmentation. Based on the airflow direction angle in the real-time airflow field distribution, when the airflow direction angle is nearly vertically upward and the temperature measuring window is located at the bottom of the cabinet, the window is at the channel inlet section. Here, the airflow has just entered from the bottom of the cabinet, with a high velocity and concentrated direction. When the temperature measuring window is located in the middle of the cabinet and the airflow direction angle has deflected somewhat, the window is at the middle section of the channel. Here, the airflow is blocked and guided by the busbar conductors, and the flow path changes. When the temperature measuring window is located at the top of the cabinet and the airflow direction angle tends to diverge, the window is at the channel outlet section. Here, the airflow is about to leave the busbar area and diffuse towards the top of the cabinet.

[0040] In one possible implementation, the labeling of airflow channel locations uses a discrete classification method. Each temperature measurement window within the thermal interference area is traversed, and the airflow direction angle corresponding to that window location is read. Based on the comparison of the direction angle with a preset angle range, the window is classified into one of three categories: channel inlet, channel middle, or channel outlet, thus completing the labeling of the airflow channel locations.

[0041] Specifically, the determination of the wind speed attenuation level is based on the energy loss law of airflow within the channel. At the channel inlet, the airflow experiences relatively low resistance upon entering the cabinet, maintaining a high level of kinetic energy; therefore, the wind speed attenuation level is set to low. As the airflow passes through the middle section of the channel, factors such as friction on the busbar conductor surface and mutual airflow interference cause some kinetic energy to be converted into heat, resulting in a decrease in flow velocity; therefore, the wind speed attenuation level is set to medium. Upon reaching the channel outlet, the increased flow space leads to airflow diffusion, reducing the airflow energy density per unit cross-section and further decreasing the flow velocity; therefore, the wind speed attenuation level is set to high.

[0042] Preferably, the attenuation coefficient is set in a corresponding relationship with the degree of wind speed attenuation. The attenuation coefficient is a value greater than zero and less than one, used to characterize the relative ability of the airflow to carry heat at each channel location. The channel inlet section corresponds to low attenuation, with a smaller attenuation coefficient value, indicating that the superimposed heat carried by the airflow at this location has a greater impact on the temperature difference, and a larger proportion is deducted during compensation. The channel middle section corresponds to medium attenuation, with an attenuation coefficient value in the middle range. The channel outlet section corresponds to high attenuation, with a larger attenuation coefficient value, indicating that the superimposed heat carried by the airflow at this location has been significantly reduced, and a smaller proportion is deducted during compensation.

[0043] For example, the attenuation coefficients for low attenuation, medium attenuation, and high attenuation are 0.2, 0.5, and 0.8, respectively.

[0044] In one embodiment, the specific process of point-by-point adjustment is as follows: For each single-point temperature difference value in the temperature difference sequence, the airflow channel position label corresponding to the temperature measurement window is read, the attenuation coefficient corresponding to the position label is found, and the attenuation coefficient is multiplied by the single-point temperature difference value to obtain the attenuated temperature difference value. This value represents the temperature difference contribution after deducting the influence of airflow attenuation.

[0045] Understandably, the attenuated temperature difference value differs from the original single-point temperature difference value, and the magnitude of this change depends on the location of the temperature measurement window within the airflow channel. Windows located at the channel inlet have a smaller adjustment range, while those at the channel outlet have a larger adjustment range. This differentiated adjustment reflects the physical characteristic that the heat transfer capacity of the airflow gradually weakens as it flows along the channel. Furthermore, all attenuated temperature difference values ​​are replaced according to the original temperature difference sequence, and this point-by-point replacement operation is performed across all temperature measurement windows within the thermal superposition interference area, forming the corrected temperature difference compensation amount. This compensation amount comprehensively considers the differences in the airflow channel location and wind speed attenuation of each temperature measurement window, reflecting the temperature offset value that should be deducted from each window location after eliminating the superposition interference of the chimney effect.

[0046] Step S104: The corrected temperature difference compensation amount is used to deduct the additional temperature rise component superimposed by the chimney effect at the temperature measurement window one by one, restore the real temperature rise data of each heat source in the cabinet conducted outward through the cabinet wall, identify abnormal temperature rise heat sources that exceed the static thermal resistance network calibration value, and determine the coordinates of potential hot spots.

[0047] The corrected temperature difference compensation is used to subtract the inner wall temperature values ​​of each temperature measuring window within the thermal superposition interference area. This temperature difference compensation is calculated by the difference between the measured inner wall temperature in the chimney effect superposition area and the interference-free reference temperature. Subtracting the corresponding temperature difference compensation from the inner wall temperature value removes the additional temperature rise component caused by the chimney effect superposition, yielding the actual temperature rise data conducted outwards through the cabinet wall at each temperature measuring window. The actual temperature rise data is compared with a pre-calibrated temperature rise reference value. The temperature rise reference value is the reference value for normal heat transfer at each temperature measuring window location under no-load operation of the switchgear. If the actual temperature rise data exceeds the temperature rise reference value at the corresponding location and the excess exceeds a preset temperature rise deviation threshold of 3.0 degrees Celsius, the heat source inside the cabinet corresponding to that temperature measuring window is determined to be an abnormal temperature rise heat source. Based on the spatial coordinates of the temperature measurement window corresponding to the abnormal temperature rise heat source, the grid node where the temperature measurement window is located is positioned in the temperature distribution matrix of the outer surface of the cabinet wall. According to the preset correspondence between the cabinet wall grid nodes and the spatial positions of the three-phase busbars inside the cabinet, the cabinet wall coordinates of the grid nodes are mapped to the spatial coordinates of the busbar region inside the cabinet. The mapping results of all abnormal temperature rise heat sources are then summarized to determine the coordinates of potential overheating points. In one method, the mapping specifically involves: first, querying a preset coordinate mapping table based on the row and column indices of the grid nodes to obtain the corresponding busbar phase identifier and axial position parameters along the busbar length; then, combining this with the fixed installation height of the busbar, calculating the specific spatial coordinates of the abnormal heat source in the busbar region inside the cabinet; and finally, summarizing the mapping results of all abnormal temperature rise heat sources to determine the coordinates of potential overheating points.

[0048] In the specific implementation of switchgear temperature monitoring, the deduction of the temperature difference compensation is a key operation for restoring the true temperature rise data. For each temperature measurement window within the thermal superposition interference area, the current inner wall temperature value of the window is read, and the corrected temperature difference compensation value corresponding to the window position is obtained. By subtracting the temperature difference compensation value from the inner wall temperature value, the additional temperature rise component caused by the chimney effect is removed, and the true temperature rise data conducted outward through the cabinet wall at that window is obtained.

[0049] For example, when the inner wall temperature of a certain temperature measuring window is a high reading and the corresponding temperature difference compensation reflects the superposition contribution of the chimney effect, the actual temperature rise data after deduction will more accurately reflect the actual heating state of the heat source behind the window, rather than the mixed temperature performance after being interfered with by the superposition of heat from other heat sources.

[0050] It should be noted that the temperature rise baseline value is the reference standard for judging abnormal temperature rise. This baseline value is calibrated under no-load conditions before the switchgear is put into operation. The specific method is as follows: with the three-phase busbars inside the cabinet not energized and no heat source inside the cabinet, record the natural heat transfer temperature rise value of the cabinet wall at each temperature measurement window position due to the ambient temperature difference. This temperature rise value reflects the inherent temperature rise characteristics caused by factors such as cabinet wall material, thickness, and ambient temperature differences, and serves as a reference baseline under normal heat transfer conditions.

[0051] In one possible implementation, the actual temperature rise data is compared point-by-point with the temperature rise reference value at the corresponding location. When the actual temperature rise data exceeds the temperature rise reference value and the excess exceeds a preset temperature rise deviation threshold, it is determined that there is abnormal heating at the location inside the cabinet corresponding to the temperature measurement window, and the heat source is marked as an abnormal temperature rise heat source. The temperature rise deviation threshold is set based on the rated operating parameters and safety margin of the switchgear.

[0052] Specifically, the determination of potential overheating point coordinates is based on the mapping relationship between the cabinet wall coordinates and the busbar coordinates inside the cabinet. During the design and manufacturing of the switchgear, the location of the temperature measuring windows and the spatial layout of the three-phase busbars inside the cabinet have a predetermined geometric correspondence. Each temperature measuring window corresponds to a grid node in the temperature distribution matrix on the outer surface of the cabinet wall. This grid node can be mapped to the spatial coordinates of the busbar area inside the cabinet through a predetermined coordinate transformation relationship. Furthermore, the mapped coordinates corresponding to all abnormal temperature rise heat sources are summarized to form a set of potential overheating point coordinates. Each coordinate point in this set indicates the spatial location of a busbar joint or conductor connection within the cabinet that may have an overheating risk.

[0053] Step S105: Based on the coordinates of potential hot spots and the heat conduction paths of the three-phase busbar and the conductors inside the cabinet, identify the proportion of heat contribution from non-target heat sources transferred to the temperature measurement window along the airflow channel, assess the extent of the underestimation of the joint temperature caused by this proportion, and update the temperature inversion results of each potential hot spot in combination with the airflow velocity to obtain an accurate estimated value of the joint temperature.

[0054] Based on the location of the potential hot spot in the three-phase busbar space within the cabinet, the heat conduction path between the hot spot and adjacent busbar joints and conductors within the cabinet is traced along the physical connection direction of the three-phase busbars. Other heat-generating components located upstream of this heat conduction path, whose heat is transferred via airflow channels to the temperature measurement window near the hot spot, are identified. These other heat-generating components are marked as non-target heat sources, thus obtaining a set of non-target heat source locations. Based on the airflow channel connectivity between each non-target heat source in this set and the current hot spot, and combining the airflow velocity and airflow direction angle in the real-time airflow field distribution characteristics, and considering the attenuation characteristic of airflow velocity gradually decreasing with increasing transmission distance, the heat contribution ratio transferred by each non-target heat source to the corresponding temperature measurement window of the hot spot is determined. This heat contribution ratio is used to assess the underestimation of the joint temperature caused by the superimposed heat from non-target heat sources received by the current hot spot. The actual temperature rise data at the corresponding temperature measurement window of the hot spot is then added to the underestimation to obtain the temperature inversion result of the hot spot. The heat contribution ratio is updated in real time by combining the dynamic changes in airflow velocity in the real-time airflow field distribution characteristics. The underestimation of each potential hot spot is recalculated based on the updated heat contribution ratio, and the temperature inversion result is corrected to obtain an accurate joint temperature estimate.

[0055] In the specific implementation of switchgear temperature monitoring, tracing the heat conduction path is fundamental to identifying non-target heat sources. For each potential hot spot, based on its coordinate position in the three-phase busbar space within the cabinet, the system traces upstream along the physical connection direction of the three-phase busbars to identify the conductor connection relationship between the hot spot and adjacent busbar joints. The heat conduction path refers to the physical channel through which heat is transferred from the heat-generating part through the busbar conductors and joint connections to the surrounding space.

[0056] For example, when a potential hot spot is located at a joint of the middle phase busbar, there are other phase busbar joints downstream of that busbar. Although the heat-generating parts of these other phases are not the current monitoring target, the heat they generate will be transferred to the temperature measurement window area near the middle phase busbar by the rising airflow inside the cabinet, resulting in heat superposition. These heat-generating parts located upstream of the airflow channel and having a superimposed effect on the current temperature measurement window reading are marked as non-target heat sources.

[0057] It should be noted that the connectivity of the airflow channel between the non-target heat source and the current overheating point determines the possibility and intensity of heat transfer. Airflow connectivity refers to whether the spatial path of airflow within the cabinet from the location of the non-target heat source to the temperature measurement window corresponding to the current overheating point is unobstructed. When the non-target heat source is located below the upward path of the airflow, and the airflow direction is towards the current temperature measurement window, there is an airflow channel connectivity between the non-target heat source and the current overheating point.

[0058] In one possible implementation, the heat contribution ratio is determined based on the attenuation characteristic of airflow velocity gradually decreasing with increasing transmission distance. As the airflow rises within the cabinet, its heat-carrying capacity gradually weakens due to friction with the busbar conductor surface, interactions between air molecules, and changes in the flow space. The farther the non-target heat source is from the temperature measurement window corresponding to the current hot spot, the longer the airflow path, and the more significant the velocity attenuation. Consequently, the proportion of heat transferred from this non-target heat source to the temperature measurement window is smaller than the total heat received by the window.

[0059] Specifically, by combining the airflow velocity values ​​from the real-time airflow field distribution characteristics, for each non-target heat source, the transfer distance along the airflow channel between its location and the current hot spot location is measured. Based on the correlation between the transfer distance and the airflow velocity, the degree of velocity attenuation along that path is determined, thus obtaining the heat contribution ratio of that non-target heat source. The heat contribution ratio represents the proportion of heat generated by the non-target heat source in the temperature reading of the temperature measurement window; a larger ratio indicates a stronger interference from the non-target heat source on the temperature measurement window.

[0060] Understandably, the underestimation of the connector temperature refers to the degree to which the displayed temperature on the temperature measuring window is inflated due to the superposition of heat from non-target heat sources, leading to a lower judgment of the actual temperature of the target heat source. When the temperature measuring window receives heat from both the target and non-target heat sources simultaneously, the displayed temperature is the result of their combined effects. If maintenance personnel directly use this displayed temperature to judge the status of the target heat source, they will underestimate the actual heat generation of the target heat source. The underestimation is obtained by multiplying the heat contribution ratio of each non-target heat source by the temperature reading on the temperature measuring window and then summing the results.

[0061] In one embodiment, the temperature inversion process is as follows: The actual temperature rise data at the temperature measurement window corresponding to the current hot spot is read, and an underestimated value is added to this actual temperature rise data to obtain the temperature inversion result for the hot spot. The temperature inversion result reflects the inferred temperature value at the target heat source junction after excluding interference from the superposition of heat from non-target heat sources.

[0062] Preferably, since the airflow field inside the cabinet is not constant, the airflow velocity and direction dynamically change with factors such as the ambient temperature outside the cabinet, the switchgear load, and the ventilation status, thus affecting the heat contribution ratio. By dynamically updating the real-time airflow field distribution characteristics, the heat contribution ratio of each non-target heat source is periodically recalculated. Based on the updated heat contribution ratio, the underestimation margin is re-determined, and the temperature inversion result is corrected. Furthermore, the dynamically updated and corrected temperature inversion result is the accurate estimate of the joint temperature. This estimate comprehensively considers the heat contribution of each non-target heat source along the heat conduction path, the attenuation characteristics of the airflow channel, and the real-time changes in the airflow field, accurately reconstructing the actual temperature state at the target heat source joint and providing reliable temperature data support for overheat risk assessment.

[0063] Step S106: Perform sliding regression fitting on the accurate estimated joint temperature value according to the time window, and analyze the change rate of abnormal temperature rise trend. When the rate of change exceeds the preset safety limit within multiple consecutive sampling periods, generate an overheating alarm signal.

[0064] A sliding time window is used to segment the precise joint temperature estimation sequence. Within each window, a linear regression is performed with the time sequence number as the independent variable and the corresponding joint temperature estimation value as the dependent variable. The slope of the resulting regression line is the rate of change k of the abnormal temperature increase within that window, expressed in degrees Celsius per minute. A preset safety upper limit k0 is set to 0.5. The calculated rate of change k for each window is compared with k0 window by window, and the number of consecutive windows where k exceeds k0 is counted. If the number of consecutive windows reaches a preset periodic threshold of 3, an overheating hotspot location alarm signal is generated for the potential overheating hotspot.

[0065] In the specific implementation of switchgear temperature monitoring, the setting of the sliding time window is determined based on the switchgear's operating characteristics and temperature change patterns.

[0066] For example, the precise joint temperature estimates are arranged into a time series according to the sampling time. A sliding window of fixed duration is set and starts from the beginning of the series, moving backward by one sampling interval each time. All temperature estimates within that time period are captured at each window position.

[0067] In one possible implementation, a linear regression is performed on the estimated joint temperature within each window. A linear relationship is established with the sampling time as the independent variable and the temperature estimate as the dependent variable. The slope of the fitted line represents the rate of change of the abnormal temperature increase trend within that window. A positive slope indicates an upward temperature trend, and a larger slope indicates a faster temperature increase.

[0068] It should be noted that the overheating hotspot location alarm signal is triggered using a continuous window determination mechanism. The rate of change of each window is compared with a preset safety limit. When the rate of change exceeds the preset safety limit, the window is recorded as an over-limit window, and the number of consecutive over-limit windows is counted. If the number of consecutive over-limit windows reaches a preset periodic threshold, it is determined that the potential overheating hotspot has a risk of continuous temperature rise, and an overheating hotspot location alarm signal is triggered at the coordinates of the overheating hotspot.

[0069] Step S107: Based on the hot spot location alarm signal and the operating load and topology of the feeder where the switch cabinet is located, identify the feeder segments and equipment that may be affected by heat, output the location of the hot spot, the estimated value of the joint temperature and the risk level of the affected area, and generate an operation and maintenance solution.

[0070] Based on the coordinates of potential hot spots contained in the hot spot location alarm signal, the current operating load data and feeder topology information of the feeder corresponding to the switchgear where the hot spot is located are obtained. The topology information includes the electrical connection relationship between the feeder and adjacent feeders and the installation position of the switchgear in the feeder. Based on the feeder topology information, the upstream and downstream electrical conduction paths are traced along the electrical connection direction of the three-phase busbar, and the heat diffusion path is analyzed based on the spatial arrangement relationship of adjacent switchgear. Feeder segments and cabinet equipment located on the above paths and having an electrical connection or heat conduction association with the current hot spot are identified, and a set of affected feeder segments and a list of affected equipment are obtained. Based on this list, combined with the operating load data of each feeder segment and the estimated joint temperature T obtained based on infrared thermography or online monitoring data, if T exceeds the preset temperature threshold of 90 degrees Celsius and the load ratio of the corresponding feeder segment exceeds the preset load threshold of 85%, it is classified as a high-risk level; if only one of the conditions is met, it is classified as a medium-risk level; and the rest are classified as low-risk levels. Output the coordinates of the hot spot location, the estimated value of the connector temperature, the set of affected feeder segments, the list of affected equipment, and the risk level of each area, and generate an operation and maintenance solution that includes maintenance priority ranking and load transfer suggestions.

[0071] In the specific implementation of switchgear temperature monitoring, after the overheating point location alarm signal is triggered, the current operating load data of the feeder corresponding to the switchgear where the overheating point is located is read from the distribution network operation database based on the coordinates of the potential overheating point carried in the alarm signal. The operating load data includes the current value carried by the feeder at the current moment, and the ratio of this current value to the rated current of the feeder is the load percentage.

[0072] For example, the feeder topology information describes the electrical connections between feeders in the distribution network and the installation location of the switchgear in the feeder power supply path. The topology information is obtained through pre-established distribution network topology data, including the upstream feeder source, downstream feeder destination, and bus connection method with adjacent switchgear.

[0073] It should be noted that tracing the overheating risk propagation path is based on the physical characteristics of heat conduction along conductors. Along the physical connection direction of the three-phase busbars, the path is traced upstream from the current overheated point to the incoming switchgear and downstream to the outgoing switchgear, identifying each switchgear and its internal busbar connections along the path. Simultaneously, based on the spatial arrangement of adjacent switchgear, it is determined whether heat is transferred to adjacent switchgear through thermal radiation or air convection between switchgear.

[0074] In one possible implementation, the identification of affected feeder segments is based on electrical connection relationships and thermal conduction correlations. Feeder segments located on the diffusion path and in the same electrical loop as the current overheating point are included in the set of affected feeder segments, and equipment located on the diffusion path and having a direct bus connection to the current overheating point or being adjacent to its cabinet are included in the list of affected equipment.

[0075] Specifically, the risk level classification adopts a dual-condition judgment method. The estimated joint temperature and operating load data for each affected feeder segment are read. When the estimated joint temperature exceeds a preset temperature threshold and the load percentage of that feeder segment exceeds a preset load threshold, the area is classified as high-risk. When only one condition (temperature exceeding limit or load exceeding limit) is met, it is classified as medium-risk. When neither condition is met, it is classified as low-risk. Furthermore, the operation and maintenance handling plan includes two parts: maintenance priority ranking and load transfer recommendations. Maintenance priority is ranked according to the risk level of each area from high to low, with high-risk areas receiving priority maintenance. Load transfer recommendations, based on the spare connection relationships in the feeder topology information, instruct the transfer of load from high-risk feeder segments to adjacent spare feeders, reducing the operating pressure on the circuits where hot spots are located.

[0076] If the technical solution of this application involves the acquisition of personal information, the product using this solution has clearly informed the user of the processing rules and obtained the user's consent before processing. If sensitive personal information is involved, the user's individual consent has been obtained and the "express consent" requirement has been met. For example, a clear sign is placed at the collection device to indicate the collection scope, and the user's voluntary entry is considered as consent; or authorization is obtained through pop-up windows, user uploads, etc. The processing rules include the processor, purpose, method, and type of information.

[0077] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. Furthermore, various different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the spirit of the present invention, and should also be regarded as the content disclosed by the present invention.

Claims

1. A method for multi-dimensional analysis and control of distribution network operation status, characterized in that, The method includes: The temperature distribution data of the outer surface of the switch cabinet wall is obtained from various areas of the switch cabinet wall. The airflow velocity and direction information are obtained from the gap of the busbar. At the same time, the temperature data of the inner and outer walls of the temperature measurement window are collected to obtain the real-time airflow field distribution characteristics. The intensity level of the chimney effect in the vertically arranged area of ​​the three-phase busbars is evaluated based on the real-time airflow field distribution characteristics, and the range of the thermal superposition interference area affected by the chimney effect is determined by combining the temperature data of the inner wall of the temperature measurement window. The temperature difference sequence between the inner and outer walls of the temperature measurement window is extracted from the area of ​​thermal superposition interference. The airflow velocity and direction data are fused together and the temperature difference sequence is adjusted point by point according to the location of each collection point in the airflow channel and the degree of wind speed attenuation to obtain the corrected temperature difference compensation amount. By using the corrected temperature difference compensation amount to deduct the additional temperature rise component superimposed by the chimney effect at the temperature measurement window one by one, the true temperature rise data of each heat source in the cabinet is restored and conducted outward through the cabinet wall. Abnormal temperature rise heat sources that exceed the static thermal resistance network calibration value are identified, and the coordinates of potential hot spots are determined. Based on the coordinates of potential hot spots and the heat conduction paths of the three-phase busbars and conductors inside the cabinet, the proportion of heat contribution from non-target heat sources transferred to the temperature measurement window along the airflow channel is identified. The extent of the underestimation of the joint temperature caused by this proportion is assessed. The temperature inversion results of each potential hot spot are updated in combination with the airflow velocity to obtain an accurate estimate of the joint temperature. The accurate estimated joint temperature is fitted by sliding regression over a time window. When the rate of change of the abnormal temperature rise exceeds the preset safety limit in multiple consecutive sampling periods, an overheating alarm signal is generated.

2. The method for multi-dimensional analysis and control of distribution network operation status according to claim 1, characterized in that, The process involves acquiring external surface temperature distribution data from various areas of the switchgear wall, obtaining airflow velocity and direction information from the busbar gap, and simultaneously collecting temperature data from the inner and outer walls of the temperature measurement window to obtain real-time airflow field distribution characteristics, including: Temperature probes are deployed in the top, middle, and bottom areas of the switchgear wall to obtain the outer surface temperature values ​​from each wall section. The outer surface temperature values ​​are mapped to the corresponding grid nodes according to the spatial coordinates of each temperature probe. The main direction of heat transfer is determined based on the temperature difference between adjacent grid nodes. Airflow velocity probes are deployed in the gaps between the three-phase buses in the vertically arranged area corresponding to this main direction to collect the airflow velocity and airflow direction angle within the gaps, thus obtaining the airflow motion parameters of the gaps. The airflow velocity probes are used to simultaneously collect the inner and outer wall temperatures of the temperature measurement window. The temperature difference gradient value of the window is obtained by subtracting the outer wall temperature from the inner wall temperature. Combined with the airflow direction angle and airflow velocity values ​​in the airflow motion parameters of the gaps, the spatial direction of the airflow channel through the temperature measurement window area is determined, thus obtaining the real-time airflow field distribution characteristics.

3. The method for multi-dimensional analysis and control of distribution network operation status according to claim 1, characterized in that, The method of assessing the chimney effect intensity level in the vertically aligned region of the three-phase busbars based on real-time airflow field distribution characteristics, and determining the range of thermal superposition interference area affected by the chimney effect by combining the inner wall temperature data of the temperature measurement window, includes: Based on the airflow velocity and airflow direction angle in the real-time airflow field distribution characteristics, the upward velocity of the airflow in the gaps between each busbar within the vertically arranged three-phase busbar region is compared. If the upward velocity exceeds a preset velocity threshold, a chimney effect is determined to exist in the vertically arranged region. The chimney effect intensity is classified into low, medium, and high levels based on the ratio of the upward velocity to the velocity threshold. The inner wall temperature data of the temperature measurement window is processed using a thermal superposition interference identification method based on the chimney effect intensity level. This method involves moving a fixed-duration sliding window along the time axis segment by segment, capturing the inner wall temperature data for the corresponding time period at each window position, and extracting the maximum temperature value from each segment of the inner wall temperature data. The difference between the minimum temperature values ​​is used as the temperature fluctuation amplitude to obtain the inner wall temperature fluctuation characteristic sequence. The inner wall temperature fluctuation characteristic sequence is compared with the chimney effect intensity level. If the temperature fluctuation amplitude increases synchronously with the increase of the chimney effect intensity level, it is determined that there is thermal superposition interference at the temperature measurement window. The spatial coordinates of the temperature measurement window are marked as thermal superposition interference points. The determination results of each temperature measurement window are summarized to obtain a set of thermal superposition interference points. According to the spatial coordinates of each interference point in the set of thermal superposition interference points, the entire temperature measurement window area covered by the extended path is defined as the thermal superposition interference area affected by the chimney effect, extending upward to the top area of ​​the cabinet wall and downward to the bottom area of ​​the cabinet wall along the vertical arrangement direction of the three-phase busbar.

4. The method for multi-dimensional analysis and control of distribution network operation status according to claim 1, characterized in that, The temperature difference sequence between the inner and outer walls of the temperature measurement window is extracted from the thermal superposition interference area. This sequence is then fused with airflow velocity and direction data, and the temperature difference sequence is adjusted point-by-point according to the location of each collection point within the airflow channel and the degree of wind speed attenuation to obtain the corrected temperature difference compensation amount. This includes: The spatial coordinates of each temperature measuring window are located within the thermal interference area. For each window, the inner and outer wall temperatures are simultaneously read. The difference between the inner and outer wall temperatures is obtained by subtracting the outer wall temperature from the inner wall temperature. All single-point temperature difference values ​​are then arranged into a sequence of inner and outer wall temperature differences according to the arrangement of the temperature measuring windows on the cabinet wall. Based on the airflow direction angle in the real-time airflow field distribution characteristics, the airflow channel position of each temperature measuring window within the thermal interference area is determined. If the temperature measuring window is located in the lower region where the airflow enters the cabinet, it is marked as the channel inlet section; if it is located in the middle region where the airflow rises, it is marked as the channel middle section. The area above the airflow outlet is marked as the channel outlet section, and the airflow channel location labels of each collection point are obtained. The wind speed attenuation degree at each collection point is determined according to the airflow channel location labels and the airflow velocity value. An increasing attenuation coefficient is set according to the wind speed attenuation degree from low to high. The attenuation coefficient is multiplied point by point by the single-point temperature difference value at the corresponding position in the temperature difference sequence to obtain the attenuated temperature difference value. The attenuated temperature difference value is used to replace the original single-point temperature difference value at the corresponding temperature measurement window position in the temperature difference sequence. All temperature measurement windows within the thermal superposition interference area are traversed to complete the point-by-point replacement, and the corrected temperature difference compensation amount is obtained.

5. The method for multi-dimensional analysis and control of distribution network operation status according to claim 1, characterized in that, The process involves subtracting the additional temperature rise component at the temperature measurement window due to the chimney effect from the corrected temperature difference compensation amount, restoring the true temperature rise data of each heat source inside the cabinet conducted outward through the cabinet wall, identifying abnormal temperature rise heat sources exceeding the static thermal resistance network calibration value, and determining the coordinates of potential hot spots, including: The corrected temperature difference compensation is used to subtract the inner wall temperature values ​​of each temperature measuring window within the thermal superposition interference area. The temperature difference compensation at the corresponding position is subtracted from the inner wall temperature value to obtain the actual temperature rise data conducted outward through the cabinet wall at each temperature measuring window. The actual temperature rise data is compared with the pre-calibrated temperature rise benchmark value. If the actual temperature rise data exceeds the temperature rise benchmark value at the corresponding position and the exceedance is greater than the preset temperature rise deviation threshold, the heat source inside the cabinet corresponding to the temperature measuring window is determined to be an abnormal temperature rise heat source. Based on the spatial coordinates of the temperature measuring window corresponding to the abnormal temperature rise heat source, the grid node where the temperature measuring window is located is located. According to the preset correspondence between the grid node of the cabinet wall and the spatial position of the three-phase bus inside the cabinet, the cabinet wall coordinates of the grid node are mapped to the spatial coordinates of the bus area inside the cabinet. The mapping results of all abnormal temperature rise heat sources are summarized to determine the coordinates of the potential hot spot.

6. The method for multi-dimensional analysis and control of distribution network operation status according to claim 1, characterized in that, The method involves identifying the proportion of heat contribution from non-target heat sources transferred to the temperature measurement window along the airflow channel based on the coordinates of potential hot spots and the heat conduction paths of the three-phase busbars and conductors within the cabinet. This proportion is then used to assess the extent of the underestimation of the joint temperature. Combined with the airflow velocity, the temperature inversion results for each potential hot spot are updated to obtain an accurate estimate of the joint temperature, including: Based on the location of the potential hot spot coordinates within the three-phase busbar space inside the cabinet, the heat conduction path between the hot spot and adjacent busbar joints and conductors inside the cabinet is traced along the physical connection direction of the three-phase busbars. Other heat-generating components located upstream of the heat conduction path, whose heat is transferred via airflow channels to the temperature measurement window near the potential hot spot, are identified. These other heat-generating components are marked as non-target heat sources, thus obtaining a set of non-target heat source locations. Based on the airflow channel connectivity between each non-target heat source in the set of non-target heat source locations and the current hot spot, the airflow velocity gradually decreases with increasing transmission distance. The attenuation characteristics are used to determine the proportion of heat contribution transferred by each non-target heat source to the temperature measurement window corresponding to the overheating point. The heat contribution proportion is used to evaluate the underestimation of the joint temperature caused by the current overheating point receiving superimposed heat from non-target heat sources. The actual temperature rise data at the temperature measurement window corresponding to the current overheating point is added to the underestimation to obtain the temperature inversion result of the overheating point. The heat contribution proportion is updated in combination with the dynamic changes in airflow velocity. The underestimation of each potential overheating point is recalculated based on the updated heat contribution proportion, and the temperature inversion result is corrected to obtain the accurate joint temperature estimate.

7. The method for multi-dimensional analysis and control of distribution network operation status according to claim 1, characterized in that, The precise estimated joint temperature is fitted using a sliding regression over a time window. When the rate of change of the abnormal temperature rise exceeds a preset safety limit within multiple consecutive sampling periods, an overheated hotspot location alarm signal is generated, including: The precise estimated joint temperature is segmented into time series using a sliding time window. Within each window, a linear regression is performed on the estimated joint temperature. The slope of the temperature change is extracted from the fitting result as the rate of change of the abnormal temperature rise trend within that window. The rate of change is compared window by window with a preset safety upper limit. The number of consecutive windows where the rate of change exceeds the preset safety upper limit is counted. If the number of consecutive windows reaches a preset periodic threshold, an overheating hotspot location alarm signal is generated for the potential overheating hotspot.

8. The method for multi-dimensional analysis and control of distribution network operation status according to claim 1, characterized in that, The method further includes: identifying feeder segments and equipment that may be affected by heat based on the hot spot location alarm signal and the operating load and topology of the feeder where the switch cabinet is located, outputting the location of the hot spot, the estimated value of the joint temperature and the risk level of the affected area, and generating an operation and maintenance solution.

9. The method for multi-dimensional analysis and control of distribution network operation status according to claim 8, characterized in that, Based on the hot spot location alarm signal and the operating load and topology of the feeder where the switchgear is located, the system identifies feeder sections and equipment that may be affected by heat, outputs the location of the hot spot, estimated joint temperature, and risk level of the affected area, and generates an operation and maintenance response plan, including: Obtain the current operating load data and feeder topology information of the feeder corresponding to the switchgear where the potential hot spot is located. The topology information includes the electrical connection relationship between the feeder and adjacent feeders and the installation position of the switchgear in the feeder. Based on the topology information along the physical connection direction of the three-phase busbar and the spatial arrangement relationship of adjacent cabinets, trace the transmission path of the overheating risk from the current hot spot to the upstream and downstream, identify the feeder segments and cabinet equipment located on the transmission path that have an electrical connection or thermal conduction association with the current hot spot, and obtain the set of affected feeder segments and the list of affected equipment. Based on the set of affected feeder segments and the list of affected equipment, combined with the operating load data of each feeder segment and the accurate joint temperature estimate, output the coordinates of the hot spot location, the estimated joint temperature, the set of affected feeder segments, the list of affected equipment, and the risk level of each area, and generate an operation and maintenance handling plan that includes maintenance priority ranking and load transfer suggestions.

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