Terminal overheating early warning method, system and power distribution switchgear

Abstract

The present application relates to the technical field of power distribution switchgear monitoring, and particularly relates to a terminal overheating early warning method and system and a power distribution switchgear. By synchronously acquiring a main loop current sequence, a terminal temperature sequence and at least one environmental reference parameter sequence in a sliding evaluation time window, and constructing a thermal disturbance indication feature, a thermal disturbance type and a reliability index in a to-be-evaluated working condition section, a thermal environmental disturbance component in terminal temperature change can be identified and quantified. Then, according to the thermal disturbance type and the reliability, the terminal temperature sequence is de-disturbance corrected or shielded, so that a de-disturbance terminal temperature rise feature which can better represent the terminal self-heating behavior is obtained. Then, a contact state physical quantity representing the terminal contact state is calculated in combination with the current characteristic parameter, and a terminal overheating early warning result is generated based on the change trend, so that the representation stability of the terminal overheating early warning to the contact state deterioration trend is improved, the false alarm risk caused by the thermal environmental disturbance is reduced, and the early warning reliability is improved.

Description

Technical Field

[0001] This invention relates to the field of power distribution switchgear monitoring technology, specifically to a terminal overheating early warning method, system, and power distribution switchgear. Background Technology

[0002] Switchgear (such as switchgear, ring main units, circuit breakers, and their primary conductive connection components) plays a crucial role in power distribution network operation, performing functions such as switching, protection, and isolation. Conductive connection terminals, as key components for main circuit current transmission and mechanical connection, directly affect operational heat generation levels due to their contact resistance, fastening condition, and conductor surface condition. When terminals experience weakened fastening force, oxidation / contamination of contact surfaces, loose connections, or insufficient conductor cross-section, localized contact deterioration and abnormal temperature rise can easily occur, potentially leading to insulation aging, ablation, or even power outages. Therefore, online monitoring and early warning of overheating in conductive connection terminals is a critical requirement in the operation and maintenance of power distribution equipment.

[0003] In existing technologies, terminal overheat monitoring typically relies on temperature detection results near the terminal and generates alarms or warnings based on preset thresholds, tiered thresholds, or delayed triggering. While this approach is easy to deploy in engineering, in actual operating environments, terminal temperature is not solely determined by contact conditions. It is also affected by factors such as ambient temperature fluctuations, changes in cabinet heat dissipation conditions, thermal coupling between adjacent conductors / components, and load disturbances. These factors may superimpose on the terminal temperature rise process at different time scales, causing the terminal temperature to exhibit a rise pattern similar to contact degradation, or masking the true overheating trend.

[0004] In this situation, early warning methods that rely solely on terminal temperature thresholds are often unable to effectively distinguish between "overheating trends caused by actual contact degradation" and "temperature rise changes caused by environmental factors, nearby heat sources, or operating condition disturbances." This can easily lead to both false alarms and missed alarms. On the one hand, temperature rises caused by environmental factors or thermal coupling may trigger early warnings, causing maintenance personnel to repeat the process and reducing their trust in early warning information. On the other hand, the overheating risk caused by continuous degradation of terminal contact conditions may be masked by external disturbances and fail to be promptly alerted, thereby increasing the risk of failure.

[0005] Therefore, there is still a need for an overheating early warning scheme for the conductive connection terminals of power distribution switchgear, which can improve the reliability and consistency of the early warning under complex thermal environment and operational disturbance conditions, so as to solve the problem that it is difficult to balance false alarms and missed alarms in the existing technology. Summary of the Invention

[0006] (i) The technical problem to be solved by the present invention is that the temperature change of the conductive connection terminals of the power distribution switch equipment is affected by the changes in load conditions and the disturbance of the thermal environment inside / around the cabinet. Existing terminal overheat warnings usually only rely on the fixed threshold of terminal temperature or temperature rise, and fail to effectively deal with the temperature rise fluctuation caused by thermal environment disturbances. It is difficult to stably reflect the overheating trend corresponding to the deterioration of terminal contact status, which easily leads to false alarms or missed alarms, and the reliability of the warning is insufficient.

[0007] (II) Technical Solution To address the aforementioned technical problems, this invention provides a terminal overheating early warning method, applied to the conductive connection terminals of a power distribution switchgear. The power distribution switchgear includes a current detection unit, a terminal temperature detection unit, and an intelligent control unit. The method is executed by the intelligent control unit and includes the following steps: S1, within the sliding evaluation time window, acquire the main circuit current sequence collected by the current detection unit, the terminal temperature sequence collected by the terminal temperature detection unit, and acquire at least one environmental reference parameter sequence, the environmental reference parameter sequence being used to characterize the thermal environment state of the terminal. S2, determine the operating condition segment to be evaluated based on the main circuit current sequence, and extract the current characteristic parameters corresponding to the operating condition segment to be evaluated; S3, within the operating condition segment to be evaluated, analyze the correlation between the changes in the terminal temperature sequence and the environmental reference parameter sequence, construct thermal disturbance indication features, and determine the thermal disturbance type and its reliability index for the current operating condition based on the preset disturbance discrimination criteria. S4. Based on the thermal disturbance type and its reliability index, perform de-disturbance correction or shielding processing on the terminal temperature sequence to obtain the de-disturbance terminal temperature rise characteristics. S5. Based on the temperature rise characteristics of the disturbance-removing terminal and the current characteristic parameters, calculate the physical quantity of the contact state that characterizes the contact state of the terminal, and generate a terminal overheating early warning result based on the changing trend of the physical quantity of the contact state.

[0008] According to an embodiment of the present invention, the disturbance discrimination criterion includes: matching the thermal disturbance indication feature with multiple disturbance fingerprint templates in a pre-stored disturbance fingerprint template set to obtain a matching score corresponding to each disturbance fingerprint template; determining the thermal disturbance type based on the disturbance fingerprint template with the largest matching score, and determining the value with the largest matching score as the confidence index, or determining the difference between the largest and second largest matching scores as the confidence index; wherein, the thermal disturbance indication feature includes the correlation coefficient between the terminal temperature sequence and the environmental reference parameter sequence in the operating condition segment to be evaluated, the time lag of the terminal temperature sequence relative to the environmental reference parameter sequence, and the percentage of the amplitude of the terminal temperature sequence changing in the same direction as the environmental reference parameter sequence.

[0009] By matching the thermal disturbance indication features constructed within the evaluation operating condition segment with multiple pre-stored disturbance fingerprint templates, and determining the thermal disturbance type based on the highest matching score, while simultaneously outputting the corresponding confidence index, the "thermal environment disturbance" can be transformed from empirical judgment into a calculable and reusable pattern recognition process. This allows disturbances from different sources and in different forms to be classified and their discrimination confidence quantified within the same discriminative framework. Specifically, the correlation coefficient characterizes the synchronicity between terminal temperature rise and changes in the thermal environment; the time lag characterizes the sequential relationship between their responses in the heat transfer chain; and the proportion of amplitude of the same-direction change characterizes the contribution of the terminal temperature rise change to the co-coupling with environmental disturbances. The combination of these three factors forms a constraint on the three-dimensional characteristics of the disturbance: "correlation-time sequence-amplitude," making the discrimination of thermal disturbance types more physically directional. Furthermore, using the maximum matching score or the difference between it and the second largest score as a reliability index can adaptively reflect the stability of the discrimination results under different operating conditions and noise levels: when the template matching shows a significant advantage, the reliability is higher, which is suitable for implementing more aggressive disturbance correction; when the scores of each template are close, the reliability decreases, indicating that the disturbance pattern of the current operating condition is atypical or the characteristics are insufficient, thus providing a basis for adopting more conservative processing strategies (such as shielding, weight reduction or delayed judgment) and reducing the warning bias introduced by misjudging the disturbance type.

[0010] According to one embodiment of the present invention, the environmental reference parameter sequence includes at least two spatially separated reference temperature sequences; The at least two reference temperature sequences are collected by temperature sensors located at at least two locations in the air region surrounding the conductive connection terminal, the conductor region adjacent to the conductive connection terminal, and the internal region of the cabinet. The temperature difference sequence between the at least two reference temperature sequences is calculated within the operating condition segment to be evaluated. The maximum absolute value of the temperature difference sequence and the rate of change of the temperature difference sequence are incorporated into the thermal disturbance indication feature to characterize the spatial temperature difference state of the thermal environment.

[0011] By introducing spatially separated multi-path reference temperatures and calculating their temperature difference sequence within the operating range, the key factor affecting terminal temperature rise interpretation—whether the thermal environment is spatially non-uniform and rapidly changing—is explicitly quantified. The maximum absolute value of the temperature difference sequence can be used to characterize the non-uniformity of the thermal field, and the rate of change of the temperature difference sequence can be used to characterize the thermal field reconstruction speed (e.g., the start-up and shutdown of nearby heat sources, changes in airflow within the cabinet, etc.). After this "spatial temperature difference state" is incorporated into the thermal disturbance indication features, disturbance judgment no longer relies solely on the correlation between terminal temperature and a single-path environmental quantity, but also possesses the ability to identify the spatial distribution of the thermal environment. This makes subsequent disturbance type determination and reliability assessment more stable and less likely to mistake temperature rise fluctuations caused by spatial thermal gradients for terminal contact degradation signals.

[0012] Further, the terminal temperature sequence is subjected to de-disturbance correction or shielding processing, including: aligning the environmental reference parameter sequence according to the time lag; determining a compensation coefficient based on the correlation coefficient between the terminal temperature sequence and the environmental reference parameter sequence within the operating condition segment to be evaluated, and calculating the disturbance temperature rise component accordingly; subtracting the disturbance temperature rise component from the terminal temperature sequence to obtain the de-disturbance terminal temperature rise feature; when the confidence index is lower than a preset confidence threshold, the shielding processing is performed, the shielding processing including marking the de-disturbance terminal temperature rise feature corresponding to the operating condition segment to be evaluated as invalid and prohibiting the generation or updating of the terminal overheating warning result based on the operating condition segment to be evaluated.

[0013] By aligning the environmental reference parameter sequence according to the time lag, the terminal temperature response and thermal environmental disturbance are made to correspond on the same time base, avoiding the impact of phase deviation caused by thermal inertia on disturbance estimation. A compensation coefficient is determined based on the correlation coefficient, and the disturbance temperature rise component is calculated accordingly, so that the estimation of the disturbance component adaptively matches the correlation degree within the operating condition range. The de-disturbed terminal temperature rise characteristic obtained by subtracting the disturbance temperature rise component from the terminal temperature sequence can be used to characterize the temperature rise behavior that more closely resembles the changes in the terminal's own contact state, thereby improving the pertinence of subsequent calculations of contact state physical quantities and early warning judgments.

[0014] When the credibility index is lower than the preset credibility threshold, the terminal temperature rise characteristics of the corresponding operating condition segment are marked as invalid, and the generation or updating of terminal overheating warning results based on the operating condition segment is prohibited. This can avoid introducing uncertain samples into the warning logic or parameter update process when the disturbance type determination is unreliable, reduce the risk of false triggering and false updating, and maintain the stability and interpretability of the warning output.

[0015] According to one embodiment of the present invention, the physical quantity of the contact state includes an equivalent thermal resistance value or an equivalent contact resistance characterization value, which is calculated based on the temperature rise characteristics of the de-disturbance terminal and the square integral of the current, wherein the square integral of the current is the square integral of the main circuit current sequence within the operating condition segment to be evaluated.

[0016] By defining the physical quantity of the contact state as an equivalent thermal resistance or equivalent contact resistance, and calculating it together with the temperature rise characteristics of the de-disturbed terminal and the square integral of the current, the "temperature rise phenomenon" can be transformed into a physical quantity characterization that is more directly related to the conductive connection state. The square integral of the current is used to characterize the intensity and accumulation of Joule heat input within the evaluated operating condition segment, reflecting the actual driving force of terminal heating in that operating condition segment better than single-point current or instantaneous peak value. Based on this, the temperature rise response after de-disturbance is correlated with this heat input, forming comparable equivalent quantities between operating conditions with different load amplitudes and durations. This makes the obtained equivalent thermal resistance / equivalent contact resistance characterization value more sensitive to "deterioration of the thermal path or increase in contact resistance due to contact degradation" and less dependent on thermal environment disturbances, thus providing a more stable basis for subsequent early warning judgments based on changing trends.

[0017] According to an embodiment of the present invention, the method further includes: maintaining a baseline parameter set for generating the thermal disturbance indication features and for calculating the physical quantities of the contact state, wherein the baseline parameter set is adaptively updated based on historical operating conditions to be evaluated when a preset update condition is met; when the terminal overheating warning result reaches a preset level, or the confidence index is lower than a preset confidence threshold, the use of data from the current operating condition to be evaluated for the adaptive update of the baseline parameter set is prohibited, so as to avoid abnormal samples from participating in the baseline parameter update.

[0018] By maintaining a baseline parameter set for generating thermal disturbance indication features and calculating physical quantities of contact states, and adaptively updating it based on historical operating conditions when preset update conditions are met, the relevant parameters can be gradually calibrated as the heat dissipation conditions change, sensor zero drift occurs, and seasonal environmental changes occur during long-term equipment operation. This avoids mismatch in the discrimination scale caused by long-term baseline solidification. Furthermore, when the terminal overheating warning result reaches a preset level or the confidence index falls below a preset confidence threshold, the data of the current operating condition to be evaluated is prohibited from being included in the baseline parameter set update. Samples that "have shown obvious abnormalities" or "disturbance type discrimination is unreliable" can be removed from the baseline update closed loop. This prevents abnormal temperature rises or strong disturbances from pulling the baseline parameters in the opposite direction, thereby reducing the risk of misjudgment in subsequent operating conditions and ensuring the consistency and stability of the warning judgment during long-term operation.

[0019] According to an embodiment of the present invention, the terminal overheating warning result includes at least a first warning level and a second warning level; wherein, when the physical quantity of the contact state exceeds the first warning threshold and continues for no less than a first duration, it is determined to be a first warning level; when the physical quantity of the contact state exceeds the second warning threshold and continues for no less than a second duration, or when the physical quantity of the contact state monotonically increases within multiple consecutive sliding evaluation time windows and the cumulative increment exceeds a preset trend threshold, it is determined to be a second warning level; and the second warning threshold is higher than the first warning threshold.

[0020] By classifying terminal overheating warning results into at least a first warning level and a second warning level, and simultaneously constraining the judgment conditions to two criteria—"exceeding the limit + duration" and "continuous deterioration trend"—the warning output can cover scenarios where the physical quantities of the contact state deteriorate rapidly in a short period of time, as well as identifying the hidden deterioration process where the risk gradually increases over multiple sliding assessment time windows. The first warning level is triggered with a lower threshold and a minimum duration to provide timely alerts for early anomalies and avoid false triggers caused by instantaneous fluctuations. The second warning level is triggered by a higher threshold and a longer duration, or by a condition of monotonically increasing increments that exceed the trend threshold, clearly escalating high-risk and continuously deteriorating states. This facilitates tiered handling and priority management under the same set of physical quantity indicators for the contact state, thereby improving the availability and consistency of warning results for operation and maintenance decisions.

[0021] According to an embodiment of the present invention, the method further includes: performing data quality checks on the terminal temperature sequence and the main circuit current sequence; when sampling loss, saturation exceeding the limit, or noise abnormality exceeding a preset ratio is detected, the corresponding operating condition segment to be evaluated is marked as invalid, and steps S3 to S5 are prohibited from being executed based on the operating condition segment to be evaluated.

[0022] By performing data quality checks on the terminal temperature sequence and main circuit current sequence before entering the disturbance discrimination and de-disturbance processing, and marking the corresponding operating condition segment to be evaluated as invalid and prohibiting further execution of steps S3 to S5 when sampling loss, saturation exceeding limits, or noise anomalies exceed a preset proportion, the construction of thermal disturbance indication features, calculation of de-disturbance terminal temperature rise characteristics, and derivation of contact state physical quantities can be avoided from the source using distorted or missing data. This prevents the introduction of false correlations, time lags, or same-direction change proportions by abnormal sampling, which could lead to misjudgment of thermal disturbance types. It also avoids generating unreliable de-disturbance correction results and contact state physical quantities when current saturation or temperature signal noise dominates, thereby reducing the risk of false alarms, missed alarms, and baseline parameters being influenced by abnormal samples, and ensuring that the early warning output is based on usable and repeatable operating condition data.

[0023] The present invention also provides a terminal overheating early warning system, integrated into the intelligent control unit of power distribution switchgear, comprising: The data acquisition module is configured to acquire the main circuit current sequence, terminal temperature sequence and at least one environmental reference parameter sequence within a sliding evaluation time window. The environmental reference parameter sequence is used to characterize the thermal environment state of the conductive connection terminal. The operating condition segment determination module is configured to determine the operating condition segment to be evaluated based on the main circuit current sequence, and extract the current characteristic parameters corresponding to the operating condition segment to be evaluated; The disturbance discrimination module is configured to analyze the correlation between the changes in the terminal temperature sequence and the environmental reference parameter sequence within the operating condition segment to be evaluated in order to construct thermal disturbance indication features, and to determine the type of thermal disturbance and its reliability index according to the preset disturbance discrimination criteria. The de-disturbance processing module is configured to perform de-disturbance correction or shielding processing on the terminal temperature sequence based on the thermal disturbance type and its reliability index, so as to obtain the de-disturbance terminal temperature rise characteristics. The physical quantity calculation module is configured to calculate the contact state physical quantity characterizing the terminal contact state based on the temperature rise characteristics of the de-disturbance terminal and the current characteristic parameters. The early warning generation module is configured to generate terminal overheating early warning results based on the changing trend of the physical quantities of the contact state.

[0024] By implementing the data acquisition, operating condition segment extraction, disturbance discrimination, disturbance removal processing, physical quantity calculation, and early warning generation processes in the terminal overheating early warning method as mutually coordinating data acquisition, operating condition segment determination, disturbance discrimination, disturbance removal processing, physical quantity calculation, and early warning generation modules, and integrating them into the intelligent control unit of the power distribution switchgear, the data input and output relationships between the modules are clearly defined, and the processing links can be automatically invoked according to a preset sequence. This provides a clear device-based implementation carrier for the terminal overheating early warning method. The system structure facilitates deployment on existing control units via software / firmware and adaptation through parameter configuration. It also facilitates the engineering management of the input data, discrimination criteria, and threshold strategies of each module, ensuring that the method is implementable, maintainable, and reusable on the equipment side.

[0025] The present invention also provides a power distribution switchgear, comprising: Conductive connection terminals; The current detection unit is used to acquire the main circuit current sequence; Terminal temperature detection unit, used to collect terminal temperature sequences; An environmental reference parameter acquisition unit is used to acquire at least one environmental reference parameter sequence. The intelligent control unit is signal-connected to the current detection unit, the terminal temperature detection unit, and the environmental reference parameter acquisition unit. The intelligent control unit is configured to execute the terminal overheat warning system described above, so as to implement the terminal overheat warning method described in any of the above claims.

[0026] By installing conductive connection terminals, current detection units, terminal temperature detection units, and environmental reference parameter acquisition units in power distribution switchgear, and connecting the intelligent control unit to these acquisition units to operate a terminal overheating early warning system, the current information, terminal temperature information, and thermal environment reference information required for terminal overheating early warning can be simultaneously acquired at the equipment side. Correlation analysis and early warning output can then be completed within the same control unit. This eliminates the need for external dedicated testing equipment or manual inspections, enabling online monitoring and early warning of terminal overheating trends during equipment operation. This structure also integrates the early warning function with the existing measurement and control hardware platform, facilitating functional expansion through control unit upgrades on existing equipment. It ensures that early warning results are generated locally and uploaded to the upper-level monitoring or maintenance interface as needed, meeting the integration and feasibility requirements of engineering applications.

[0027] (III) Beneficial effects of the present invention: By simultaneously acquiring the main circuit current sequence, terminal temperature sequence and at least one environmental reference parameter sequence within the sliding evaluation time window, and constructing thermal disturbance indication features, identifying thermal disturbance types and reliability indicators within the evaluation operating condition segment, the thermal environment disturbance components in the terminal temperature change can be identified and quantified; then, based on the thermal disturbance type and reliability, the terminal temperature sequence is de-disturbed and corrected or shielded to obtain a de-disturbed terminal temperature rise characteristic that better represents the terminal's own heating behavior; then, combined with the current characteristic parameters, the physical quantity of the contact state characterizing the terminal contact state is calculated, and the terminal overheating early warning result is generated based on its changing trend, thereby improving the stability of the terminal overheating early warning in characterizing the contact state deterioration trend, reducing the risk of false alarms and missed alarms caused by thermal environment disturbances, and improving the reliability of the early warning. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of a power distribution switchgear and terminal overheat warning system provided in one embodiment of the present invention; Figure 2This is a schematic flowchart of a terminal overheat warning method provided in one embodiment of the present invention. Detailed Implementation

[0030] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation

[0031] During the operation of conductive connection terminals in power distribution switchgear, terminal temperature rise may originate from actual heat generation caused by deterioration of terminal contact conditions, or be affected by external thermal disturbances such as changes in the cabinet's thermal environment and heat transfer from adjacent conductors. This can lead to unstable or uninterpretable warnings based solely on terminal temperature thresholds. To address these issues, this embodiment provides a terminal overheat warning method, system, and power distribution switchgear.

[0032] like Figure 1As shown, the power distribution switchgear in this embodiment includes at least conductive connection terminals, a current detection unit, a terminal temperature detection unit, an environmental reference parameter acquisition unit, and an intelligent control unit. The conductive connection terminals can be cable terminals, busbar connection terminals, or circuit breaker incoming / outgoing terminals, etc. This embodiment takes the three-phase busbar-circuit breaker incoming terminal connection point in a low-voltage distribution cabinet as an example. This location has high current, many contact interfaces, and is significantly affected by the internal thermal environment of the cabinet, making it suitable as a typical target for terminal overheating early warning. The current detection unit can use a current transformer, a Hall current sensor, or a shunt sampling circuit. This embodiment preferably uses a three-phase current transformer on the circuit breaker incoming side to collect the main circuit current sequence. The advantages are strong anti-interference capability, minimal modification to the main circuit, and ease of long-term stable operation. The terminal temperature detection unit can employ thermocouples, thermistors, platinum resistance thermometers, or digital temperature sensors. In this embodiment, a surface-mount platinum resistance temperature sensor is preferably placed near the crimp / lap joint of each phase conductive connection terminal to collect the terminal temperature sequence. This offers advantages such as good temperature linearity, low long-term drift, and the installation location directly reflects localized contact heating at the terminal. The environmental reference parameter acquisition unit is used to acquire at least one environmental reference parameter sequence. In some implementations, only the reference temperature sequence may be acquired; in others, auxiliary quantities related to the thermal environment, such as fan status and cabinet door opening / closing status, may be superimposed. This embodiment uses "at least two spatially separated reference temperature sequences" as the environmental reference parameter sequence: the first reference temperature sensor is arranged in the air area around the conductive connection terminal (close to the terminal but insulated from it), and the second reference temperature sensor is arranged inside the cabinet near the ventilation channel / top hot area to reflect the overall thermal environment changes inside the cabinet; the advantage of using two points is that it can capture both local hot air disturbances near the terminal and spatial temperature difference changes caused by overall temperature rise or heat source migration inside the cabinet, providing a more stable reference for the construction of subsequent thermal disturbance indication features.

[0033] The intelligent control unit is signal-connected to the current detection unit, terminal temperature detection unit, and environmental reference parameter acquisition unit. In this embodiment, the intelligent control unit preferably includes a processor, memory, a real-time clock / timer, an analog-to-digital converter and acquisition interface, and a communication interface. The processor can be an MCU or an embedded processor. The memory stores the program, sliding window cache data, and a pre-stored set of disturbance fingerprint templates. The analog-to-digital converter and acquisition interface is used for synchronous sampling or timestamp-aligned sampling of the current / temperature sensor outputs. The communication interface is used to upload the warning results to a host computer or station control system. To facilitate the implementation of sliding evaluation time windows and operating condition segment processing, this embodiment uses a ring buffer to cache the current sequence, terminal temperature sequence, and environmental reference parameter sequence, and manages them with a unified sampling period or unified timestamp for alignment. This allows subsequent thermal disturbance indication features such as correlation coefficients, time lag, and the proportion of same-direction change amplitudes to be calculated within the same operating condition segment to be evaluated.

[0034] In terms of software / firmware implementation, the terminal overheat warning system is integrated into the intelligent control unit as a program module, including at least a data acquisition module, a working condition segment determination module, a disturbance discrimination module, a disturbance removal processing module, a physical quantity calculation module, and a warning generation module: The data acquisition module reads the main circuit current sequence, terminal temperature sequence, and environmental reference parameter sequence within the sliding evaluation time window from the annular buffer; the working condition segment determination module identifies a relatively stable time period that meets the evaluation conditions on the current sequence as the working condition segment to be evaluated, and forms current characteristic parameters within this segment; the disturbance discrimination module calculates the correlation coefficient between the terminal temperature sequence and the environmental reference parameter sequence, the time lag of the terminal temperature relative to the environmental reference parameter, and the proportion of the same direction change amplitude within the working condition segment to be evaluated, and compares the thermal disturbance indication characteristics with... The pre-stored set of disturbance fingerprint templates is matched to obtain a matching score, thereby determining the type of thermal disturbance and its credibility index. When the credibility meets the threshold, the de-disturbance processing module performs time alignment on the environmental reference parameter sequence based on the time lag, and determines a compensation coefficient based on the correlation coefficient to estimate the disturbance temperature rise component. This component is then subtracted from the terminal temperature sequence to obtain the de-disturbed terminal temperature rise characteristic. When the credibility is below the threshold, the evaluation condition segment is shielded (e.g., marked as invalid and prohibited from generating or updating warning results). The physical quantity calculation module calculates contact state physical quantities (e.g., equivalent thermal resistance or equivalent contact resistance characterization value) based on the de-disturbed terminal temperature rise characteristic and current characteristic parameters. The warning generation module outputs the terminal overheating warning result based on the changing trend of the contact state physical quantities. Through the above implementation chain of hardware acquisition—cache alignment—feature calculation—template matching—de-disturbance—physical quantity calculation, this embodiment provides a directly reproducible system carrier and implementation principle, providing a clear foundation for the specific implementation of subsequent method steps.

[0035] Based on the aforementioned power distribution switchgear and terminal overheating early warning system, this embodiment implements the terminal overheating early warning method as software / firmware within the intelligent control unit. The intelligent control unit synchronously samples the main circuit current sequence I(n) and the terminal temperature sequence T_term(n) with a sampling period Δt, and writes the data from the most recent period into a circular buffer to support the rolling calculation of the sliding evaluation time window. Simultaneously, the environmental reference parameter sequence in this embodiment uses two spatially separated reference temperature sequences, T_ref1(n) and T_ref2(n), where T_ref1(n) is collected by a temperature sensor located in the air region surrounding the conductive connection terminals, and T_ref2(n) is collected by a temperature sensor located in the area inside the cabinet. To facilitate subsequent correlation analysis, this embodiment defines the environmental reference parameter sequence as T_env(n) = (T_ref1(n) + T_ref2(n)) / 2, and calculates the temperature difference sequence ΔT_ref(n) = T_ref1(n) - T_ref2(n) between the two reference temperature sequences within the operating condition segment to be evaluated. The rate of change characteristics of max(|ΔT_ref(n)|) and ΔT_ref(n) are incorporated into the thermal disturbance indication characteristics to characterize the spatial temperature difference state of the thermal environment. In this embodiment, the rate of change characteristic rate(ΔT_ref) can be obtained by discrete difference, for example, the average absolute rate of change within the operating condition segment to be evaluated is taken as: rate(ΔT_ref) = mean(|ΔT_ref(n) - ΔT_ref(n-1)|) / Δt.

[0036] like Figure 2 As shown, the steps are as follows: In step S1, the intelligent control unit reads the sampling sequences of I(n), T_term(n), T_env(n), T_ref1(n), and T_ref2(n) within the sliding evaluation time window, and marks abnormal samples such as sampling loss and saturation exceeding limits to ensure the availability of input data for subsequent feature extraction. In step S2, the intelligent control unit determines the operating condition segment to be evaluated based on the main circuit current sequence: I(n) is segmented statistically within the sliding evaluation time window, and a segment in which the current change enters a relatively stable state and continuously meets the preset length requirement is selected as the operating condition segment to be evaluated, and the current characteristic parameters corresponding to the operating condition segment to be evaluated are extracted; wherein, the relatively stable state can be understood as the short-term fluctuation of the current meeting the preset constraints, such as the sliding standard deviation of the current not exceeding the sliding mean within the statistical window and continuously meeting the preset length requirement. To support the subsequent calculation of physical quantities of the contact state, this embodiment extracts at least the average current, peak current, and current square integral Q_I2 of the operating condition to be evaluated. Q_I2 is calculated in discrete form as Q_I2=Σ(I(n)^2×Δt), and the summation range is the start and end sampling points of the operating condition to be evaluated.

[0037] In step S3, the intelligent control unit analyzes the correlation between the changes in the terminal temperature sequence and the environmental reference parameter sequence within the operating condition segment to be evaluated to construct thermal disturbance indication features. In this embodiment, the correlation coefficient between the terminal temperature sequence T_term(n) and the environmental reference sequence T_env(n) is denoted as r, and calculated using the Pearson correlation coefficient: r=Σ[(T_term(n)-mean(T_term))×(T_env(n)-mean(T_env))] / sqrt(Σ(T_term(n)-mean(T_term))^2 × Σ(T_env(n)-mean(T_env))^2), where mean(·) is the mean value calculation within the operating condition segment to be evaluated. The time lag of the terminal temperature sequence relative to the environmental reference sequence is denoted as L (in units of sampling points). In this embodiment, L is obtained by finding the lag that maximizes the cross-correlation strength within a finite lag search range, and then normalized to L_n = L / L_max (where L_max is the number of sampling points corresponding to the preset maximum lag). L_max can be determined based on the terminal thermal inertia and sampling period to cover the main lag range of the terminal temperature response to environmental changes. The proportion of the amplitude of the terminal temperature sequence changing in the same direction as the environmental reference sequence is denoted as P_same. In this embodiment, the proportion of samples with the same sign for adjacent sampling increments is used for calculation, that is, the number of samples that satisfy sign(T_term(n)-T_term(n-1))=sign(T_env(n)-T_env(n-1)) is counted and divided by the total number of samples in the operating condition segment to be evaluated. Combining the aforementioned spatial temperature difference state characteristics max(|ΔT_ref(n)|) and the rate of change of ΔT_ref(n), the intelligent control unit obtains the thermal disturbance indication feature vector V=[r,L_n,P_same,max(|ΔT_ref|), rate(ΔT_ref)] for the current operating condition. In this embodiment, the disturbance discrimination criterion is implemented using a matching method based on a set of disturbance fingerprint templates: each pre-stored disturbance fingerprint template corresponds to a central feature vector V_i. The intelligent control unit calculates the matching distance D_i=sqrt(Σ_k (V[k]-V_i[k])^2) for each template and calculates the matching score S_i=1 / (1+D_i) accordingly. The template with the largest S_i is taken as the thermal disturbance type determination result, and the maximum matching score C=max(S_i) is used as the reliability index. This allows the thermal disturbance type and the reliability index to be given by the same set of matching operation loops, facilitating the unified invocation of subsequent disturbance removal processing intensity and shielding strategies.Furthermore, to avoid the "black box" of "unclear template source", the disturbance fingerprint template set described in this embodiment can be pre-constructed during the factory debugging or operation and maintenance calibration stage: sample data under various typical thermal disturbance scenarios are collected under typical equipment operating environment, feature vector V is calculated for each group of samples in the above manner, and multiple groups of feature vectors under the same scenario are clustered or statistically summarized. The center vector of the sample in this class is taken as the disturbance fingerprint template V_i corresponding to the scenario and stored in the disturbance fingerprint template set, so that the template matching has a reproducible calibration source.

[0038] In step S4, the intelligent control unit performs de-disturbance correction or shielding processing on the terminal temperature sequence according to the thermal disturbance type and confidence index to obtain the de-disturbance terminal temperature rise characteristics. In this embodiment, the de-disturbance correction processing is performed when the confidence index C is not lower than the preset confidence threshold, and the shielding processing is performed directly when C is lower than the preset confidence threshold. The preset confidence threshold can be determined by historical sample backtesting or operation and maintenance data statistics, and is used to distinguish between "type discrimination confidence" and "type discrimination insufficient to support correction" operating conditions. In this embodiment, the environmental reference sequence is first time-aligned according to the time lag L to obtain T_env'(n) = T_env(n-L), and the environmental change ΔT_env'(n) = T_env'(n) - T_env'(n0) is constructed based on the sampling point n0 at the starting point of the operating condition to be evaluated. Subsequently, the intelligent control unit determines the compensation coefficient k based on the linear fit between T_term(n) and T_env'(n) within the evaluated operating condition segment, specifically using the least squares slope form: k = Σ[(T_env'(n) - mean(T_env')) × (T_term(n) - mean(T_term))] / Σ(T_env'(n) - mean(T_env'))^2. To ensure that the compensation strength is constrained by the strength of the correlation, this embodiment scales the compensation coefficient according to the magnitude of the correlation coefficient, obtaining k' = k × |r|, and calculates the disturbance temperature rise component T_dist(n) = k' × ΔT_env'(n) accordingly. The intelligent control unit subtracts the disturbance temperature rise component from the terminal temperature sequence to obtain the disturbance-free terminal temperature rise characteristic corresponding to the disturbance-free terminal temperature rise sequence T_de(n) = T_term(n) - T_dist(n). When the confidence index C is lower than the preset confidence threshold, the intelligent control unit performs a shielding process on the operating condition segment to be evaluated, that is, marks the disturbance-free terminal temperature rise characteristic corresponding to the operating condition segment to be evaluated as invalid, and prohibits the generation or updating of terminal overheat warning results based on the operating condition segment to be evaluated, thereby avoiding overcompensation or misjudgment when the disturbance type is uncertain.

[0039] In step S5, the intelligent control unit calculates the physical quantity of the contact state characterizing the terminal contact state based on the temperature rise characteristics and current characteristic parameters of the disturbance-removed terminal, and generates a terminal overheating warning result according to its changing trend. In this embodiment, the equivalent thermal resistance value R_th is used as the physical quantity of the contact state: the disturbance-removed temperature rise ΔT_de(n) = T_de(n) - T_de(n0) is constructed based on the starting point n0 of the operating condition to be evaluated, the cumulative quantity Q_T = Σ(ΔT_de(n) × Δt) corresponding to the square integral of the temperature rise is calculated, and the equivalent thermal resistance value is obtained according to R_th = Q_T / Q_I2. The intelligent control unit forms a time series of R_th calculated by the continuous sliding evaluation time window, and determines the warning level according to the preset first warning threshold, second warning threshold and corresponding duration; the first warning threshold and second warning threshold can be set after being converted to the R_th domain based on the equipment factory temperature rise test data, historical healthy operation data or engineering tuning rules. The determination method is as follows: when R_th exceeds the first warning threshold and continues for no less than the first duration, the first warning level is output; when R_th exceeds the second warning threshold and continues for no less than the second duration, the second warning level is output. In addition, in order to reflect the gradual nature of contact degradation, this embodiment monitors the monotonically increasing trend of R_th within multiple consecutive sliding evaluation time windows. When the cumulative increment exceeds the preset trend threshold, the second warning level is also output, and the second warning threshold is kept higher than the first warning threshold, so that the warning results have consistent determinability and reproducibility under the two typical evolution paths of "continuous exceeding the limit" and "monotonically deteriorating".

[0040] In addition to the single evaluation in steps S1 to S5 above, to ensure consistency and reproducibility of thermal disturbance discrimination and contact state evaluation during long-term operation, this embodiment maintains a "baseline parameter set" within the intelligent control unit and uses it as the basic configuration for generating thermal disturbance indication features and calculating contact state physical quantities. In this embodiment, the baseline parameter set includes at least: the central feature vector of each disturbance fingerprint template in the disturbance fingerprint template set and its normalization range parameters, the allowable search range and normalization upper limit of the time lag, the judgment thresholds for correlation coefficients and confidence indices, and a reference baseline (e.g., the reference mean and fluctuation bandwidth of contact state physical quantities under healthy operating conditions) used to form trend discrimination of contact state physical quantities. The intelligent control unit only allows adaptive updates of the baseline parameter set using historical operating conditions to be evaluated when preset update conditions are met; in this embodiment, the preset update conditions are: the operating condition to be evaluated has completed data quality checks and been determined to be valid; the confidence index meets the preset confidence threshold requirements; and the terminal overheating warning result has not reached the preset level. When the above conditions are met, the intelligent control unit uses the thermal disturbance indication features extracted from the current working condition segment to be evaluated to update the corresponding disturbance fingerprint template parameters, and simultaneously updates the reference baseline of the physical quantity of the contact state smoothly, so that the template and the baseline gradually converge as the long-term heat dissipation conditions and installation tightness of the equipment change slowly. Conversely, when the terminal overheating warning result reaches the preset level, or the confidence index is lower than the preset confidence threshold, the intelligent control unit prohibits the use of the data of the current working condition segment to be evaluated for the adaptive update of the baseline parameter set, so that the abnormal samples corresponding to the alarm working condition and the low confidence working condition will not reverse "train" the template and the baseline, avoiding the misjudgment caused by threshold drift and template offset.

[0041] Furthermore, to ensure the engineering usability of the data entering the disturbance discrimination and de-disturbance calculation, this embodiment, after forming the operating condition segment to be evaluated in steps S1 and S2, first performs a data quality check on the terminal temperature sequence and the main circuit current sequence, and uses this as a gate condition for entering steps S3 to S5. In this embodiment, the data quality check covers at least three types of anomalies: first, sampling loss, where the intelligent control unit determines whether there are continuous or cumulative sampling losses exceeding limits within the operating condition segment to be evaluated by using sampling count, timestamp increment consistency, or ring buffer gap detection; second, saturation exceeding limits, where the intelligent control unit determines whether there is prolonged edge contact or instantaneous saturation based on the upper / lower limits of the temperature sensor range, the full-scale mark of the AD conversion, or the amplitude limit mark of the current sampling channel; and third, the proportion of noise anomalies, where the intelligent control unit uses the proportion of high-frequency jitter, the density of abrupt change points, or the deviation of variance from the baseline in the sequence within the operating condition segment to be evaluated as a noise anomaly characterization, and compares it with a preset proportional threshold. If sampling loss, saturation exceeding limits, or abnormal noise exceeding a preset proportion is detected, the corresponding test condition segment will be marked as invalid, and steps S3 to S5 will be prohibited based on the test condition segment. At the same time, the invalidation mark will also serve as an exclusion condition for baseline parameter set updates, so that test conditions with substandard data quality will not participate in disturbance type identification and disturbance removal correction, nor in the adaptive update of templates and baselines, thereby reducing the risk of misjudgment, missed judgment, and baseline contamination caused by abnormal sampling from the source.

[0042] The above are preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made to the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A terminal overheating early warning method, applied to the conductive connection terminals of a power distribution switchgear, wherein the power distribution switchgear includes a current detection unit, a terminal temperature detection unit, and an intelligent control unit, characterized in that... Performed by the intelligent control unit, the steps include: S1, within the sliding evaluation time window, acquire the main circuit current sequence collected by the current detection unit, the terminal temperature sequence collected by the terminal temperature detection unit, and acquire at least one environmental reference parameter sequence, the environmental reference parameter sequence being used to characterize the thermal environment state of the terminal. S2, determine the operating condition segment to be evaluated based on the main circuit current sequence, and extract the current characteristic parameters corresponding to the operating condition segment to be evaluated; S3, within the operating condition segment to be evaluated, analyze the correlation between the changes in the terminal temperature sequence and the environmental reference parameter sequence, construct thermal disturbance indication features, and determine the thermal disturbance type and its reliability index for the current operating condition based on the preset disturbance discrimination criteria. S4. Based on the thermal disturbance type and its reliability index, perform de-disturbance correction or shielding processing on the terminal temperature sequence to obtain the de-disturbance terminal temperature rise characteristics. S5. Based on the temperature rise characteristics of the disturbance-removing terminal and the current characteristic parameters, calculate the physical quantity of the contact state that characterizes the contact state of the terminal, and generate a terminal overheating early warning result based on the changing trend of the physical quantity of the contact state.

2. The terminal overheating early warning method according to claim 1, characterized in that, The disturbance discrimination criterion includes: matching the thermal disturbance indication features with multiple disturbance fingerprint templates in a pre-stored disturbance fingerprint template set to obtain a matching score corresponding to each disturbance fingerprint template; determining the thermal disturbance type based on the disturbance fingerprint template with the largest matching score, and determining the value with the largest matching score as the credibility index, or determining the difference between the largest and second largest matching scores as the credibility index; wherein, the thermal disturbance indication features include the correlation coefficient between the terminal temperature sequence and the environmental reference parameter sequence in the operating condition segment to be evaluated, the time lag of the terminal temperature sequence relative to the environmental reference parameter sequence, and the percentage of the amplitude of the terminal temperature sequence changing in the same direction as the environmental reference parameter sequence.

3. The terminal overheating early warning method according to claim 1, characterized in that, The environmental reference parameter sequence includes at least two spatially separated reference temperature sequences; The at least two reference temperature sequences are collected by temperature sensors located at at least two locations in the air region surrounding the conductive connection terminal, the conductor region adjacent to the conductive connection terminal, and the internal region of the cabinet. The temperature difference sequence between the at least two reference temperature sequences is calculated within the operating condition segment to be evaluated. The maximum absolute value of the temperature difference sequence and the rate of change of the temperature difference sequence are incorporated into the thermal disturbance indication feature to characterize the spatial temperature difference state of the thermal environment.

4. The terminal overheating early warning method according to claim 2, characterized in that, The step of performing de-disturbance correction or shielding processing on the terminal temperature sequence includes: aligning the environmental reference parameter sequence according to the time lag; determining a compensation coefficient based on the correlation coefficient between the terminal temperature sequence and the environmental reference parameter sequence within the operating condition segment to be evaluated; and calculating the disturbance temperature rise component accordingly; subtracting the disturbance temperature rise component from the terminal temperature sequence to obtain the de-disturbance terminal temperature rise characteristic; and performing the shielding processing when the confidence index is lower than a preset confidence threshold, wherein the shielding processing includes marking the de-disturbance terminal temperature rise characteristic corresponding to the operating condition segment to be evaluated as invalid and prohibiting the generation or updating of the terminal overheating warning result based on the operating condition segment to be evaluated.

5. The terminal overheating early warning method according to claim 1, characterized in that, The physical quantities of the contact state include equivalent thermal resistance or equivalent contact resistance characterization values, which are calculated based on the temperature rise characteristics of the de-disturbance terminal and the square integral of the current, wherein the square integral of the current is the square integral of the main circuit current sequence within the operating condition segment to be evaluated.

6. The terminal overheating early warning method according to claim 1, characterized in that, The method further includes: maintaining a baseline parameter set for generating the thermal disturbance indication features and for calculating the physical quantities of the contact state, wherein the baseline parameter set is adaptively updated based on historical operating conditions to be evaluated when preset update conditions are met; when the terminal overheating warning result reaches a preset level, or the confidence index is lower than a preset confidence threshold, the data of the current operating condition to be evaluated is prohibited from being used for the adaptive update of the baseline parameter set, so as to avoid abnormal samples from participating in the baseline parameter update.

7. The terminal overheating early warning method according to claim 1, characterized in that, The terminal overheating warning result includes at least a first warning level and a second warning level; wherein, when the physical quantity of the contact state exceeds the first warning threshold and continues for no less than a first duration, it is determined to be a first warning level; when the physical quantity of the contact state exceeds the second warning threshold and continues for no less than a second duration, or when the physical quantity of the contact state monotonically increases within multiple consecutive sliding evaluation time windows and the cumulative increment exceeds a preset trend threshold, it is determined to be a second warning level; and the second warning threshold is higher than the first warning threshold.

8. The terminal overheating early warning method according to claim 1, characterized in that, The method further includes: performing data quality checks on the terminal temperature sequence and the main circuit current sequence; when sampling loss, saturation exceeding the limit, or noise abnormality exceeding the preset ratio is detected, the corresponding operating condition segment to be evaluated is marked as invalid, and steps S3 to S5 are prohibited from being executed based on the operating condition segment to be evaluated.

9. A terminal overheating early warning system, integrated into the intelligent control unit of a power distribution switchgear, characterized in that, include: The data acquisition module is configured to acquire the main circuit current sequence, terminal temperature sequence and at least one environmental reference parameter sequence within a sliding evaluation time window. The environmental reference parameter sequence is used to characterize the thermal environment state of the conductive connection terminal. The operating condition segment determination module is configured to determine the operating condition segment to be evaluated based on the main circuit current sequence, and extract the current characteristic parameters corresponding to the operating condition segment to be evaluated; The disturbance discrimination module is configured to analyze the correlation between the changes in the terminal temperature sequence and the environmental reference parameter sequence within the operating condition segment to be evaluated in order to construct thermal disturbance indication features, and to determine the type of thermal disturbance and its reliability index according to the preset disturbance discrimination criteria. The de-disturbance processing module is configured to perform de-disturbance correction or shielding processing on the terminal temperature sequence based on the thermal disturbance type and its reliability index, so as to obtain the de-disturbance terminal temperature rise characteristics. The physical quantity calculation module is configured to calculate the contact state physical quantity characterizing the terminal contact state based on the temperature rise characteristics of the de-disturbance terminal and the current characteristic parameters. The early warning generation module is configured to generate terminal overheating early warning results based on the changing trend of the physical quantities of the contact state.

10. A power distribution switchgear, characterized in that, include: Conductive connection terminals; The current detection unit is used to acquire the main circuit current sequence; Terminal temperature detection unit, used to collect terminal temperature sequences; An environmental reference parameter acquisition unit is used to acquire at least one environmental reference parameter sequence. The intelligent control unit is signal-connected to the current detection unit, the terminal temperature detection unit, and the environmental reference parameter acquisition unit. The intelligent control unit is configured to operate the terminal overheat warning system of claim 9 to implement the terminal overheat warning method of any one of claims 1 to 8.

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