A mechanical characteristic on-line monitoring system for switch cabinet

Abstract

This invention relates to the field of switchgear monitoring technology and discloses an online monitoring system for the mechanical characteristics of switchgear, comprising: data acquisition; calculation of the energy storage input integral; extraction of the electromagnetic release time; calculation of the structural transmission delay; calculation of the baseline delay; calculation of the health benchmark of the structural temperature sensitivity coefficient; and output of monitoring results. This invention separates the additional mechanical delay caused by temperature variations in the upper and lower contact boxes of the switchgear from the overall action delay, distinguishing the effects of temperature coupling and conventional factors such as uniform temperature energy storage input on mechanical action. The monitoring process relies on electrical and temperature signals, eliminating the need for additional mechanical displacement sensors. It is adaptable to the internal space and insulation constraints of switchgear and can be used for monitoring new equipment commissioning and intelligent upgrading of in-operation equipment. It can provide corresponding reference information for switchgear condition assessment and operation and maintenance decisions, meeting the operation and management needs of the entire life cycle of switchgear.

Description

Technical Field

[0001] This invention relates to the field of switchgear monitoring technology, and more specifically, to an online monitoring system for the mechanical characteristics of switchgear. Background Technology

[0002] Switchgear is a widely used medium-voltage switchgear in 10kV to 35kV indoor power distribution networks, and its mechanical operating characteristics directly affect the stability of the power grid. Current monitoring of switchgear mechanical characteristics mainly focuses on the operating parameters of the circuit breaker itself. Conventional monitoring methods center on closing and opening times, coil current amplitude, and auxiliary contact position signals, with some schemes using external displacement sensors to obtain mechanical motion parameters. These monitoring methods follow the monitoring logic of independent circuit breakers, failing to consider the switchgear's cabinet structure and compartment distribution characteristics, and neglecting to take into account the thermal differences between the upper and lower areas of the cabinet. Traditional monitoring can only obtain the overall operating delay, unable to break down the components of the delay, making it difficult to adapt to the unique operating conditions of switchgear.

[0003] The switchgear contains upper and lower contact boxes, which connect to the busbar and cable circuits respectively, serving as the mechanical connectors for electrical connections and heat conduction during operation. The compartments containing the upper and lower contact boxes naturally differ in heat dissipation and current-carrying characteristics, easily leading to temperature differences between the upper and lower areas during long-term operation. These temperature differences cause uneven thermal expansion of the upper and lower structures, altering the equivalent stress distribution within the mechanism and causing a shift in the pre-tension state. This structural change caused by vertical temperature variations generates additional mechanical delays, a technical issue unique to switchgear structures; independent circuit breakers do not exhibit this characteristic.

[0004] Existing monitoring technologies cannot separate the additional delay caused by temperature variations in the upper and lower contact boxes from the overall delay, typically attributing all delay anomalies to conventional factors such as mechanical wear and insufficient energy storage. Furthermore, existing solutions often output multi-dimensional indicators or dimensionless evaluation results, failing to generate single-valued quantitative results to characterize the abnormal impact of temperature coupling. Offline detection methods cannot capture the transient characteristics of the closing process in real time, while online monitoring solutions lack feature extraction logic for vertical temperature variations in the switchgear. This makes it impossible for maintenance personnel to determine whether delay anomalies originate from temperature coupling between the upper and lower structures, hindering the timely detection of potential structural hazards and failing to provide data support for targeted maintenance of the switchgear. Summary of the Invention

[0005] This invention provides an online monitoring system for the mechanical characteristics of switchgear, which solves the technical problems mentioned in the background.

[0006] This invention provides an online monitoring system for the mechanical characteristics of switchgear, comprising: The data acquisition module synchronously acquires the closing coil current, energy storage motor current, primary side transient voltage, primary side transient current, upper contact box temperature at the start of the action, and lower contact box temperature at the start of the action during the closing action. The energy storage input integral calculation module calculates the uniform temperature and vertical differential temperature based on the temperature of the upper and lower contact boxes, and performs integral calculation on the energy storage motor current to obtain the energy storage input integral. The electromagnetic release timing extraction module extracts the extreme points of the second derivative of the closing coil current as a function of time as the electromagnetic release timing. The structural propagation delay calculation module integrates the rate of change of the primary transient voltage and the rate of change of the primary transient current to construct a composite slope, extracts the extreme point of the composite slope as the actual engagement time, and uses the time difference between the actual engagement time and the electromagnetic release time as the structural propagation delay. The baseline delay calculation module constructs a baseline delay model by combining historical health samples, and calculates the baseline delay by substituting the average temperature and energy storage input integrals into the baseline delay model. The health baseline calculation module divides the difference between the structural transfer delay and the baseline delay by the vertical anisothermal effect to obtain the structural anisothermal sensitivity coefficient, and combines it with historical health samples to calculate the health baseline of the structural anisothermal sensitivity coefficient. The monitoring results output module calculates and outputs single-valued online mechanical monitoring results based on vertical temperature variation and the difference between the structural temperature variation sensitivity coefficient and the health baseline.

[0007] The beneficial effects of this invention are as follows: This invention utilizes the existing structure of the switchgear for deployment, requiring no mechanical modification to the cabinet and not affecting its original insulation performance or operating status. This invention can separate the additional mechanical delay caused by temperature differences between the upper and lower contact boxes of the switchgear from the overall action delay, distinguishing the effects of temperature coupling and conventional factors such as uniform temperature energy storage input on mechanical action. This invention outputs single-valued quantitative monitoring results, presenting the equipment status in time units, facilitating understanding and use by on-site maintenance personnel. The monitoring process relies on electrical and temperature signals, eliminating the need for additional mechanical displacement sensors, and is adaptable to the internal space and insulation constraints of the switchgear. Furthermore, this invention enables continuous online monitoring of closing actions, retaining complete historical data to form a reference for changes in equipment status. It is compatible with indoor switchgear of different voltage levels and can be used for new equipment commissioning monitoring and intelligent transformation of in-operation equipment, providing corresponding reference information for switchgear status assessment and maintenance decisions, meeting the operational management needs of the switchgear throughout its entire lifecycle. Attached Figure Description

[0008] Figure 1 This is a calculation flowchart of an online monitoring system for the mechanical characteristics of a switchgear according to the present invention; Figure 2This is a calculation scenario diagram of an online monitoring system for the mechanical characteristics of a switchgear according to the present invention. Detailed Implementation

[0009] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, features described in some examples may be combined in other examples.

[0010] It should be noted that, unless otherwise defined, the technical or scientific terms used in one or more embodiments of the present invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in one or more embodiments of the present invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" indicate that the element or object preceding the term encompasses the elements or objects listed following the term and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0011] like Figures 1-2 As shown, an online monitoring system for the mechanical characteristics of a switchgear includes: The data acquisition module synchronously acquires the closing coil current, energy storage motor current, primary side transient voltage, primary side transient current, upper contact box temperature at the start of the action, and lower contact box temperature at the start of the action during the closing action. The energy storage input integral calculation module calculates the uniform temperature and vertical differential temperature based on the temperature of the upper and lower contact boxes, and performs integral calculation on the energy storage motor current to obtain the energy storage input integral. The electromagnetic release timing extraction module extracts the extreme points of the second derivative of the closing coil current as a function of time as the electromagnetic release timing. The structural propagation delay calculation module integrates the rate of change of the primary transient voltage and the rate of change of the primary transient current to construct a composite slope, extracts the extreme point of the composite slope as the actual engagement time, and uses the time difference between the actual engagement time and the electromagnetic release time as the structural propagation delay. The baseline delay calculation module constructs a baseline delay model by combining historical health samples, and calculates the baseline delay by substituting the average temperature and energy storage input integrals into the baseline delay model. The health baseline calculation module divides the difference between the structural transfer delay and the baseline delay by the vertical anisothermal effect to obtain the structural anisothermal sensitivity coefficient, and combines it with historical health samples to calculate the health baseline of the structural anisothermal sensitivity coefficient. The monitoring results output module calculates and outputs single-valued online mechanical monitoring results based on vertical temperature variation and the difference between the structural temperature variation sensitivity coefficient and the health baseline.

[0012] In one embodiment of the present invention, synchronously acquiring the closing coil current, energy storage motor current, primary side transient voltage, primary side transient current, upper contact box temperature at the start of the operation, and lower contact box temperature at the start of the operation during the closing action includes: With the first The start time of the secondary closing action Using time as the reference, construct the first Data window corresponding to the second closing action It satisfies the formula: ; in For the first The data window corresponding to the next closing action. For the first The start time of the next closing action The start time of the action Previous pre-collection duration, The start time of the action Subsequent data collection duration; In the data window Internal synchronous acquisition of closing coil current Energy storage motor current Primary transient voltage and primary transient current And all domains satisfy ;in For the first The time sequence of the closing coil current corresponding to the next closing action. In order to be with the first Time series of energy storage motor current associated with the second closing action. For the first The time sequence of the primary side transient voltage corresponding to the next closing action. For the first The time sequence of the primary side transient current corresponding to the next closing action. Sampling time; At the start of the action Temperature of the upper contact box at the start of the acquisition action Temperature of the lower contact box at the start of the action ;in For the first The start time of the secondary closing action The temperature of the upper contact box at the start of the corresponding action. For the first The start time of the secondary closing action The temperature of the lower contact box at the start of the corresponding action; Integrated closing coil current Energy storage motor current Primary transient voltage Primary transient current Temperature of the upper contact box at the start of the action And the temperature of the lower contact box at the start of the action. Form an output data set It satisfies the formula: ; in For the first The set of output data generated during the second closing action.

[0013] It should be noted that the pre-acquisition duration is the time length set before the start time of the action to capture the associated electrical signals before the closing action. A preferred value is 50 to 200 milliseconds. This range covers the final stage of the energy storage motor current and the preparatory signals before the closing coil is energized, ensuring complete acquisition of the electrical signals associated with the closing action. The subsequent acquisition duration is the time length set after the start time of the action to capture the electrical signals throughout the entire closing action process. A preferred value is 300 to 800 milliseconds. This range covers the entire process of closing coil energization, electromagnetic mechanism operation, and primary side transient signal changes, ensuring no missing electrical signals related to the closing action. The closing coil current is the change in the current value of the closing coil during the closing action, reflecting the energization of the closing coil and the operating state of the electromagnetic mechanism. It can be acquired by a Hall current sensor connected in series in the closing coil circuit. The energy storage motor current is the change in the current value of the energy storage motor associated with the closing action, and it can be acquired by a Hall current sensor connected in series in the energy storage motor circuit. The primary-side transient voltage is the instantaneous voltage change on the high-voltage side of the main circuit during closing action, reflecting the transient voltage response of the main circuit. It can be acquired by a voltage transformer installed on the primary side of the switchgear. The primary-side transient current is the instantaneous current change on the high-voltage side of the main circuit during closing action, reflecting the transient current response of the main circuit. It can be acquired by a current transformer installed on the primary side of the switchgear. The upper contact box temperature at the start of the action is the temperature value of the upper contact box area of ​​the switchgear at the start of the closing action, reflecting the thermal state of the upper contact box at the start of the closing action. It can be acquired by a platinum resistance temperature sensor mounted on the outer wall of the upper contact box. The lower contact box temperature at the start of the action is the temperature value of the lower contact box area of ​​the switchgear at the start of the closing action, reflecting the thermal state of the lower contact box at the start of the closing action. It can be acquired by a platinum resistance temperature sensor mounted on the outer wall of the lower contact box.

[0014] It should be noted that the pre-acquisition duration can be adjusted according to the switchgear model and the operating characteristics of the energy storage motor in practical applications. For small switchgear, 50 to 100 milliseconds is used, and for large switchgear, 100 to 200 milliseconds is used. The core purpose is to cover the final current of the energy storage motor and the preparatory signals before the closing coil is energized. The subsequent acquisition duration can be adjusted according to the closing action time of the switchgear in practical applications. For switchgear with a shorter closing action time, 300 to 500 milliseconds is used, and for switchgear with a longer closing action time, 500 to 800 milliseconds is used. The core purpose is to cover the electrical signal changes throughout the entire closing process. The data window uses the start time of the closing action as the zero point. The pre-acquisition duration before the zero point is the beginning of the window, and the subsequent acquisition duration after the zero point is the end of the window, forming a continuous time interval from the beginning to the end, uninterruptedly covering the pre-closing preparation and the closing process. The synchronous acquisition of multiple electrical signals employs a unified synchronous triggering module. This module receives the action start command for the closing action as a trigger signal and simultaneously sends sampling trigger commands to each electrical signal acquisition sensor. All sensors begin sampling simultaneously upon receiving the trigger commands, and the sampling frequency of all sensors remains consistent. Furthermore, the mechanical characteristics of the switchgear's closing action are influenced by multiple factors, including the electromagnetic mechanism's action, energy storage preparation, main circuit transient response, and contact box thermal state. Acquiring only one type of physical quantity cannot fully reflect the mechanical characteristics of the closing action. Synchronously acquiring electrical and temperature signals allows for the correlation between changes in these factors and the mechanical process of the closing action.

[0015] It should be noted that this invention uses the start time of the closing action as a unified time reference to construct a data window, synchronously collecting electrical and temperature signals related to the closing action. By limiting the data window, a strong correlation between the sampled data and the closing action is achieved, eliminating irrelevant signal interference. Simultaneously, the contact box temperature is collected at the start of the action to ensure spatiotemporal matching between the temperature data and the closing action. This aligns the collected multi-physical quantity data in the time dimension, providing complete and relevant basic data for subsequent analysis of the mechanical characteristics of the closing action. The data window setting ensures the relevance of the collected data and avoids redundancy of irrelevant data. The synchronous acquisition allows the changes in each physical quantity to correspond one-to-one with the mechanical process of the closing action. The accurate acquisition of the contact box temperature accurately reflects the thermal state at the start of the closing action, laying a reliable data foundation for subsequent feature extraction and time delay calculation.

[0016] In one embodiment of the present invention, the energy storage motor current is integrated to obtain the energy storage input integral by calculating the uniform temperature and vertical temperature difference based on the upper contact box temperature and the lower contact box temperature, including: extract Temperature of the upper contact box at the start of the action Temperature of the lower contact box at the start of the action and the current of the energy storage motor ; Calculate the average temperature It satisfies the formula: ; in For the first Temperature equalization corresponding to the second closing action. For the first The start time of the secondary closing action The temperature of the upper contact box at the start of the corresponding action. For the first The start time of the secondary closing action The temperature of the lower contact box at the start of the corresponding action; Calculate vertical differential temperature It satisfies the formula: ; in For the first The vertical temperature difference corresponding to the second closing action; In the data window Internal determination of the starting time of the energy storage motor current With the termination time of the energy storage motor current And from the starting moment of the energy storage motor current With the termination time of the energy storage motor current Determine the integration interval And satisfy as well as ; Calculate the energy storage input integral It satisfies the formula: ; in For the first The energy storage input integral corresponding to the next closing action. In order to be with the first Time series of energy storage motor current associated with the second closing action. For the first The starting time of the energy storage motor current associated with the second closing action. For the first The termination time of the energy storage motor current associated with the second closing action; Combined temperature equalization Vertical heterotherm and energy storage input integral Form the output parameter set It satisfies the formula: ; in For the first The set of output parameters formed during the next closing action.

[0017] It should be noted that the uniform temperature reflects the overall thermal background state of the upper and lower contact box areas of the switchgear at the start of the closing action. Vertical temperature variation reflects the degree of thermal difference between the upper and lower contact boxes of the switchgear at the start of the closing action. The integration interval is the time range defined by the start and end times of the energy storage motor current, reflecting the effective time interval for integrating the energy storage motor current. The energy storage input integral is the result of integrating the energy storage motor current with respect to time within the integration interval, reflecting the overall input intensity of the energy storage process associated with this closing action. The specific method for determining the start time of the energy storage motor current within the data window is to first calibrate the static baseline value of the current when the energy storage motor is not working. The threshold is set at 1.2 times the baseline value when the current rises within the data window. When the current reaches this threshold for three consecutive sampling points, this moment is determined as the start time of the energy storage motor current. The specific method for determining the end time of the energy storage motor current within the data window is to set the threshold at 1.1 times the static baseline value when the current falls back from the working state within the data window. When the current is below this threshold for five consecutive sampling points, this moment is determined as the end time of the energy storage motor current. In addition, the unit for collecting the current of the energy storage motor is amperes, the unit for sampling time is seconds, and the unit for the integration result is calibrated as ampere-seconds.

[0018] It should be noted that the upper and lower contact boxes of the switchgear are the core mechanical and electrical connection areas for the closing action. The temperature of a single contact box cannot represent the overall thermal situation of this core area; the average temperature of both boxes can comprehensively reflect the overall thermal background. The heat dissipation boundaries and current-carrying conditions of the upper and lower contact boxes of the switchgear naturally differ, and the temperature difference directly reflects the degree of thermal asymmetry between them. This difference affects the equivalent force distribution of the mechanism links. This invention, based on the temperatures of the upper and lower contact boxes at the start of the closing action, extracts the average temperature representing the overall thermal background and the vertical temperature difference representing the thermal difference between the upper and lower boxes through arithmetic mean and difference calculations. Simultaneously, within the dedicated closing data window, the effective integration interval of the energy storage motor current is determined, and the energy storage input integral, which comprehensively represents the energy storage input intensity, is obtained through integration calculations. This transforms the raw temperature and current data into characteristic quantities with clear engineering interpretability, enabling quantitative differentiation of the thermal state characteristics of the switchgear contact box and freeing the energy storage input intensity from the limitations of a single indicator. All characteristic quantities are strongly correlated with the current closing action, eliminating interference from irrelevant data. The transformed characteristic quantities provide accurate quantitative basis for subsequent baseline modeling and time delay decomposition, ensuring the effectiveness and consistency of subsequent analysis data.

[0019] In one embodiment of the present invention, extracting the extreme point of the second derivative of the closing coil current as a function of time as the electromagnetic release moment includes: Call the closing coil current and data window And meet the following conditions: ;in For the first The time sequence of the closing coil current corresponding to the next closing action. For the first The data window corresponding to the next closing action. For data window Sampling time within; In the data window Internal determination of closing coil current Power-on start time And meet the following conditions: ;in For the first During the second closing operation, the current in the closing coil... The moment when the power is applied; For the closing coil current Regarding time Find the second derivative and take its absolute value to construct a scalar function of the second derivative. It satisfies the formula: ; in For the first During the second closing operation, the current in the closing coil... The second derivative scalar function; In satisfying Under the condition of extracting the scalar function of the second derivative The moment corresponding to the first local maximum is taken as the electromagnetic release moment. It satisfies the formula: ; in For the first The electromagnetic release time corresponding to the next closing action. The second derivative scalar function Conditions for stationing troops This is a criterion for determining local maxima. The goal is to select the earliest time among all times that satisfy the given conditions.

[0020] It should be noted that the energization start moment is the moment when the closing coil current in the data window transitions from a static, de-energized state to an energized, changing state, reflecting the time node when the electromagnetic mechanism of the closing coil begins to receive electrical signals. The second derivative quantitative function is a function obtained by taking the absolute value of the second derivative of the closing coil current with respect to time, reflecting the degree of curvature of the closing coil current curve at each moment. The electromagnetic release moment is the moment corresponding to the first local maximum point of the second derivative quantitative function after the energization start moment, reflecting the time node when the electromagnetic mechanism begins to truly drive the mechanical chain to produce effective action. The first derivative of the closing coil current only reflects the rate of change of the current, while the second derivative reflects the change in the rate of change of the current. At the instant when the electromagnetic mechanism overcomes static friction and drives the mechanical chain, the current curve will show a significant bend, and the second derivative will form an extremum. Taking the absolute value can eliminate the influence of the bend direction, retaining only the characteristic of the severity of the bend. Before the energization start moment, the closing coil is in a static, de-energized state, with no electrical signal response and no mechanical action associated characteristics. After this moment, the coil begins to build magnetism and gradually acts on the mechanical mechanism; only the signal during this stage is related to mechanical action. The instant the electromagnetic mechanism begins to drive the mechanical chain is the moment when the current curve bends most sharply, corresponding to the first local maximum of the second derivative scalar function. This moment precedes subsequent processes such as contact movement and main circuit conduction, and is the true starting point of the mechanical action. Furthermore, a moving average filtering method can be used to process the original closing coil current data. The number of sampling points in the filtering window is preferably set to 5. The arithmetic mean of 5 consecutive sampling points is calculated sequentially, and the sampling value at the center of the window is replaced to complete the full-sequence filtering, eliminating sampling glitches and high-frequency interference, and preventing noise from distorting the second derivative calculation results.

[0021] It should be noted that this invention relies on the electrical signal change characteristics of the closing coil current to determine the energization start time within a dedicated data window for the closing action. This serves as the effective boundary for the electromagnetic mechanism's electrical signal response. First, the coil current is preprocessed to remove noise. Then, a numerical function is constructed by calculating the second derivative and taking its absolute value. The first local maximum of this function after the energization start time is extracted, thus locating the electromagnetic release time. This operation requires no additional mechanical sensors, adapts to the insulation and space constraints of the switchgear, ensures the accuracy of the derivative calculation through signal preprocessing, eliminates invalid signals using the energization start time as the boundary, and the local maximum determination rule ensures the uniqueness of the electromagnetic release time location. The extracted electromagnetic release time provides a unified and reliable time reference for subsequent structural transmission delay calculations, allowing for accurate time starting points for subsequent delay decomposition and coupling analysis.

[0022] In one embodiment of the present invention, a composite slope is constructed by fusing the rate of change of the primary-side transient voltage and the rate of change of the primary-side transient current. The extreme point of the composite slope is extracted as the actual engagement time. The time difference between the actual engagement time and the electromagnetic release time is used as the structural propagation delay, including: Calling the primary transient voltage Primary transient current Data window and the electromagnetic release time And meet the following conditions: ;in For the first The time sequence of the primary side transient voltage corresponding to the next closing action. For the first The time sequence of the primary side transient current corresponding to the next closing action. For the first The data window corresponding to the next closing action. For the first The electromagnetic release time corresponding to the next closing action. For data window Sampling time within; Transient voltage on the primary side and primary transient current Regarding time respectively Find the first derivative to obtain the rate of change of the transient voltage on the primary side. and the rate of change of the primary transient current ; Calculate the scaling factor It satisfies the formula: ; in For the first The proportional factor corresponding to the next closing action. For data window The root mean square value of the rate of change of the transient voltage on the inner primary side. For data window The root mean square value of the rate of change of the transient current on the inner primary side; Construct composite slope It satisfies the formula: ; in For the first The composite slope corresponding to the second closing action; In satisfying Extracting the composite slope under the given conditions The moment corresponding to the first local maximum is taken as the actual moment of contact. It satisfies the formula: ; in For the first The actual moment of closing corresponds to the second closing action. Composite slope Conditions for stationing troops This is a criterion for determining local maxima. To select the earliest time among all times that meet the conditions; Computational structure propagation delay It satisfies the formula: ; in For the first The structural transmission delay corresponding to the second closing action.

[0023] It should be noted that the rate of change of the primary transient voltage is obtained by taking the first derivative of the primary transient voltage with respect to time, reflecting how quickly the primary transient voltage changes with time. The rate of change of the primary transient current is obtained by taking the first derivative of the primary transient current with respect to time, reflecting how quickly the primary transient current changes with time. The scaling factor is the ratio of the root mean square value of the rate of change of the primary transient voltage to the root mean square value of the rate of change of the current within the data window, reflecting the quantization coefficient for scaling the voltage and current rates of change. The composite slope is a comprehensive quantity obtained by combining the rates of change of the primary transient voltage and the rate of change of the current using the scaling factor, reflecting the transient impact intensity of the transient electrical signal during the main circuit closing process. The actual closing moment is the moment corresponding to the local maximum point where the composite slope first appears after the electromagnetic release moment, reflecting the time node when the moving and stationary contacts of the main circuit of the switchgear establish effective electrical conduction. The structural transmission delay is the time difference between the actual closing moment and the electromagnetic release moment, reflecting the overall time consumed by the electromechanical transmission chain from the action of the electromagnetic mechanism to the effective conduction of the main circuit.

[0024] It should be noted that when the moving and stationary contacts in the main circuit are not in contact, the transient voltage and current on the primary side are in a relatively stable state, and the first derivative value is close to 0. At the instant the contacts close, the voltage and current change abruptly, and the first derivative immediately forms a significant extremum. This extremum can be used to accurately capture this transient electrical event. For example, if the voltage is stable at 10 kV before the contacts close and suddenly drops to 0 kV at the moment of contact, the rate of change of voltage will show a large negative extremum, clearly demonstrating the characteristics of contact closing. The moment of electromagnetic release is the starting point of mechanical action. Afterward, the moving contact gradually moves towards the stationary contact until it closes and forms effective conduction. During this process, the transient impact intensity of the transient electrical signal will first rise and then fall. The first local maximum point is the moment of maximum impact intensity, that is, the instant the contacts close. This moment can accurately correspond to the physical event of the main circuit being turned on. In addition, the moving average filtering method can be used to preprocess the signal before calculating the first derivative of the transient voltage and current on the primary side. The number of sampling points in the filtering window is preferably set to 5. The arithmetic mean of the 5 consecutive sampling points is calculated in sequence, and the sampling value at the center of the window is replaced to complete the full sequence filtering, remove high-frequency interference and glitches in the sampling process, and avoid noise from causing distortion of the derivative calculation results.

[0025] It should be noted that this invention relies on the electrical signal characteristics of transient voltage and current on the primary side. First, the original signal is preprocessed to remove noise. Then, the first derivative is calculated to obtain the rate of change reflecting transient changes. A scaling factor is constructed using the root mean square ratio to achieve scale matching between the two signals. After fusion, a composite slope that comprehensively characterizes the transient impact intensity is formed. The first local maximum of the composite slope after the electromagnetic release is extracted to locate the actual engagement moment. Finally, the time difference between this point and the electromagnetic release moment is calculated to obtain the structural transmission delay. Similarly, no additional mechanical sensors are required, adapting to the installation and insulation constraints of switchgear. The scaling factor solves the dimensional difference problem between voltage and current rates of change. The composite slope integrates dual signal characteristics, improving the stability of engagement moment identification. The local maximum determination rule ensures the uniqueness of the actual engagement moment location. Validity verification ensures the rationality of the extraction results. The calculated structural transmission delay provides a core electromechanical transmission quantification indicator for subsequent baseline modeling and heterogeneous temperature sensitivity coefficient calculation, providing an accurate basis for subsequent additional delay decomposition.

[0026] In one embodiment of the present invention, a baseline delay model is constructed by combining historical health samples, and the baseline delay is calculated by substituting the average temperature and energy storage input integrals into the baseline delay model, including: Call the first Temperature equalization corresponding to the second closing action and the Energy storage input integral corresponding to the second closing action Call the first Structural propagation delay corresponding to the secondary closing action And call the average temperature corresponding to the historical healthy samples. Energy storage input integral corresponding to historical health samples and the structural propagation delay corresponding to historical healthy samples ; Constructing the first based on historical health samples Baseline delay model input for each historical health sample It satisfies the formula: ; in For the first The baseline time delay model input for each historical health sample For the position of the constant term, Integral input for energy storage corresponding to historical health samples The reciprocal of; and simultaneously construct the first The baseline delay model output term corresponding to each historical health sample It satisfies the formula: ; in For the first The baseline time delay model output term corresponding to each historical health sample; Input the baseline time delay model corresponding to all historical health samples. Combine to form the input matrix The baseline time delay model output terms corresponding to all historical health samples will be generated. Combine to form the output vector And calculate the baseline delay model parameters. It satisfies the formula: ; in These are the baseline delay model parameters. For the input matrix The transpose of the matrix, For matrix The inverse matrix; the baseline delay model parameters Expanded representation: ; in These are the constant parameters of the baseline delay model. These are the model parameters corresponding to the average temperature. The model parameters corresponding to the inverse integral of the energy storage input; According to the Temperature equalization corresponding to the second closing action and the Energy storage input integral corresponding to the second closing action Construct the first Baseline delay model input for the second closing action It satisfies the formula: ; in For the first The baseline delay model input for the second closing action. For the first Energy storage input integral corresponding to the second closing action The reciprocal of; The first Baseline delay model input for the second closing action Substituting into the baseline delay model, the first time delay is calculated. Baseline delay corresponding to the second closing action It satisfies the formula: ; in For the first Baseline delay corresponding to the second closing action.

[0027] It should be noted that the input terms of the baseline delay model corresponding to historical healthy samples are a combination of features consisting of a constant term, the average temperature of the historical healthy samples, and the reciprocal of the energy storage input integral of the historical healthy samples, reflecting the characteristics of the effect of conventional influencing factors on structural transmission delay under historical healthy conditions. The output terms of the baseline delay model corresponding to historical healthy samples are the structural transmission delay of the historical healthy samples, reflecting the actual value of the structural transmission delay corresponding to conventional influencing factors under historical healthy conditions. The input matrix is ​​a matrix formed by sequentially combining the input terms of the baseline delay model of all historical healthy samples, reflecting the overall characteristic distribution of conventional influencing factors in the historical healthy samples. The output vector is a vector formed by sequentially combining the output terms of the baseline delay model of all historical healthy samples, reflecting the overall numerical distribution of structural transmission delay in the historical healthy samples. The baseline delay model parameters are a set of coefficients obtained by solving the input matrix and output vector, reflecting the quantitative influence of the average temperature and the reciprocal of the energy storage input integral on the structural transmission delay. The input terms of the baseline delay model corresponding to the closing action are a combination of features consisting of a constant term, the average temperature of the current closing action, and the reciprocal of the energy storage input integral of the current closing action, reflecting the characteristics of the effect of conventional influencing factors under the current operating condition. Baseline delay is the delay value calculated by linearly combining the current closed model input with the baseline delay model parameters, reflecting the structural transmission delay that the equipment should have under the current operating conditions.

[0028] It should be noted that the selection criteria for historical health samples are data collected during periods when the equipment had no fault records, the structure had not undergone any repairs or modifications, and the closing action was normal. The minimum number of historical health samples is 50 sets. This number ensures the accuracy of model fitting and avoids overfitting due to insufficient sample size. The specific construction rule for the baseline delay model input terms corresponding to historical health samples is to arrange them in the following order: constant term 1, average temperature of historical health samples, and reciprocal of the integral of the energy storage input of historical health samples, forming a one-dimensional row vector. Each element in the vector is retained to three decimal places to ensure a consistent format for the input terms. The specific combination and dimension matching method of the input matrix and output vector is as follows: the row vectors of the input terms of each historical health sample are arranged in the order of collection time, forming an input matrix with the number of rows equal to the number of samples and the number of columns equal to 3; the output terms of each historical health sample are arranged in the same time order, forming an output vector with the number of rows equal to the number of samples and the number of columns equal to 1, thus achieving dimension matching between the matrix and the vector. The baseline delay model parameters are solved using the least squares method. First, the transpose of the input matrix is ​​calculated. Then, the product of the transpose and the original input matrix is ​​calculated, and the inverse of this product matrix is ​​obtained. This inverse is then multiplied by the transpose. Finally, the result is multiplied by the output vector to obtain the baseline delay model parameters. The validity criterion for the baseline delay model parameters is to substitute the solved parameters into the input terms of historical healthy samples, calculate the fitted delay, and statistically analyze the error between the fitted delay and the historical actual delay. If the average error is less than 5 milliseconds and the maximum error is less than 10 milliseconds, the model parameters are considered valid.

[0029] It should be noted that this invention relies on historical health samples of the equipment to construct model input terms consisting of constant terms, temperature uniformity, and the inverse integral of energy storage input, and model output terms centered on structural transmission delay. Input and output terms from multiple sets of samples are respectively organized into input matrices and output vectors. Baseline delay model parameters are solved through standardized calculations. Then, the model input terms for the current closing action are constructed, and the baseline delay is calculated by linearly combining them with the model parameters. An individualized model is constructed based on the equipment's own health data, adapting to the individual differences of different equipment. The model input terms comprehensively cover the common factors affecting structural transmission delay, effectively isolating the effects of temperature uniformity and energy storage input. The solution of model parameters and the validity judgment rules ensure the accuracy of the model, providing reliable health reference values ​​for subsequent extraction of additional delays caused by structural anomalies, and providing a clear comparative benchmark for subsequent analysis of the effects of temperature coupling.

[0030] In one embodiment of the present invention, the difference between the structural transfer delay and the baseline delay is divided by the vertical anisothermal effect to obtain the structural anisothermal sensitivity coefficient, and a health benchmark for the structural anisothermal sensitivity coefficient is calculated by combining historical health samples, including: Call the first Structural propagation delay corresponding to the secondary closing action , No. Baseline delay corresponding to the second closing action and the Vertical temperature variation corresponding to the second closing action And call the structure corresponding to the historical healthy sample to pass the delay. Baseline delay corresponding to historical health samples and the vertical anisotropy corresponding to historical healthy samples ; Calculate the first The time delay difference corresponding to the second closing action It satisfies the formula: ; in For the first The time delay difference corresponding to the second closing action. For the first The structural transmission delay corresponding to the second closing action. For the first Baseline delay corresponding to the second closing action; Calculate the first Structural temperature sensitivity coefficient corresponding to the secondary closing action It satisfies the formula: ; in For the first The structural temperature sensitivity coefficient corresponding to the second closing action. For the first The vertical temperature difference corresponding to the second closing action; Calculate the first Time delay difference corresponding to each historical health sample It satisfies the formula: ; in For the first The time delay difference corresponding to each historical healthy sample For the first The structural propagation delay corresponding to each historical healthy sample For the first Baseline latency corresponding to each historical health sample; Calculate the first Structural isothermal sensitivity coefficient corresponding to a historical healthy sample It satisfies the formula: ; in For the first Structural isothermal sensitivity coefficients corresponding to historical healthy samples For the first Vertical anisotropy corresponding to each historical healthy sample; Health benchmark for calculating structural temperature sensitivity coefficient It satisfies the formula: ; in As a health benchmark for structural temperature sensitivity coefficient, The number of historical healthy samples used in the calculation. For the first Structural isothermal sensitivity coefficients corresponding to historical healthy samples.

[0031] It should be noted that the delay difference is the difference between the structural transmission delay and the baseline delay, reflecting the additional delay caused by the closing action after eliminating the influence of uniform temperature and energy storage input. The structural temperature sensitivity coefficient is the ratio of the delay difference to the vertical temperature difference, reflecting the additional delay sensitivity caused by the unit temperature difference between the upper and lower contact boxes. The delay difference corresponding to the historical healthy sample is the difference between the structural transmission delay and the baseline delay of the historical healthy sample, reflecting the additional delay value under the equipment's healthy state. The structural temperature sensitivity coefficient corresponding to the historical healthy sample is the ratio of the delay difference to the vertical temperature difference of the historical healthy sample, reflecting the unit temperature-related additional delay sensitivity under the equipment's healthy state. The health benchmark for the structural temperature sensitivity coefficient is the result of averaging the structural temperature sensitivity coefficients corresponding to the historical healthy samples, reflecting the reference value of the structural temperature sensitivity coefficient under the equipment's healthy state.

[0032] It should be noted that the baseline delay is the normal delay under the current operating conditions and health status, while the structural transmission delay is the actual measured total delay. The difference between the two can eliminate the thermal background effect from the uniform temperature and the energy input effect from the energy storage input, retaining only the additional delay caused by unconventional factors such as structural anomalies. For example, if the baseline delay is 20 milliseconds and the actual structural transmission delay is 25 milliseconds, the 5-millisecond difference is the additional delay after eliminating the normal effects. The larger the sensitivity coefficient, the more additional delay is caused by a unit temperature difference, and the tighter the coupling between vertical temperature variation and mechanical delay. This coefficient can transform the invisible structural stress changes into quantifiable characteristic values, intuitively reflecting the degree of influence of structural temperature variation coupling. The number of historical health samples used in the health benchmark calculation should be consistent with the minimum requirement for historical health samples, preferably 50 groups. This number ensures the statistical reliability of the health benchmark and avoids the benchmark value deviating from the true health characteristics of the equipment due to insufficient sample size.

[0033] It should be noted that this invention first calculates the difference between the structural transmission delay and the baseline delay, stripping away the conventional influences of temperature equalization and energy storage input to obtain the additional delay caused only by unconventional factors. Then, this difference is compared with the vertical temperature variation to quantify the sensitivity of the additional delay caused by a unit of temperature variation, i.e., the structural temperature variation sensitivity coefficient. Simultaneously, the same calculation process is performed on historical healthy samples. After outlier removal, the average is taken to obtain the sensitivity coefficient health benchmark adapted to the equipment itself. This transforms the coupling relationship between vertical and vertical temperature variations and additional delay unique to switchgear into a quantifiable characteristic coefficient, achieving an intuitive representation of invisible structural stress changes. Outlier removal and validity verification rules ensure the statistical reliability of the coefficient and the health benchmark. Based on the benchmark value of the equipment's own health samples, and adapted to individual structural and operational differences, the coefficient after removing conventional influences can accurately point to structural changes caused by temperature variation coupling. This provides core characteristic basis for the subsequent output of single-valued monitoring results, giving the determination of structural anomalies a clear quantitative standard.

[0034] In one embodiment of the present invention, based on vertical anisotropic temperature and the difference between the structural anisotropic temperature sensitivity coefficient and the health baseline, a single-valued online mechanical monitoring result is calculated and output, including: Call the first Vertical temperature variation corresponding to the second closing action and the Structural temperature sensitivity coefficient corresponding to the secondary closing action Health benchmarks for structural temperature sensitivity coefficients ;in For the first The vertical temperature variation corresponding to the second closing action For the first The structural temperature sensitivity coefficient corresponding to the second closing action. As a health benchmark for structural temperature sensitivity coefficient; Calculate the difference between the structural temperature sensitivity coefficient and the healthy baseline. It satisfies the formula: ; in For the first The difference between the structural temperature sensitivity coefficient and the health baseline corresponding to the second closing action; Calculate the single-valued online monitoring results of machinery It satisfies the formula: ; Or it can be expressed as: ; in For the first The single-valued online mechanical monitoring results corresponding to the next closing action This is for absolute value operations.

[0035] It should be noted that the difference between the structural temperature anomaly sensitivity coefficient and the health baseline is the result of subtracting the health baseline from the current structural temperature anomaly sensitivity coefficient, reflecting the degree of deviation of the current structural temperature anomaly sensitivity relative to the equipment's health status. The single-valued online mechanical monitoring result is the product of the absolute value of the vertical temperature anomaly and the absolute value of the difference between the structural temperature anomaly sensitivity coefficient and the health baseline, reflecting the abnormal additional mechanical delay caused by the coupling of temperature anomalies between the upper and lower parts of the switchgear, exceeding the healthy state. The health baseline is the sensitivity reference value when the equipment has no structural abnormalities. The difference between the current sensitivity and the baseline directly reflects the deviation of the sensitivity; the larger the difference, the more significant the difference between the current structural state and the healthy state. Vertical temperature anomalies can be positive or negative, only indicating that the upper or lower contact box is hotter. The actual impact of thermal differences is only related to the amplitude; taking the absolute value can uniformly characterize the strength of the temperature anomaly. The abnormal additional delay caused by temperature anomaly coupling is affected by both the temperature anomaly amplitude and the degree of sensitivity deviation. Multiplying the two can integrate the influence of the two dimensions into a single quantitative value, achieving a single-valued representation of the influence of multiple factors. In addition, the specific output form of the single-valued mechanical online monitoring results adopts digital signals, synchronously outputting numerical values ​​and units, supporting real-time display on the field display screen and uploading via remote communication interface; the data storage requirements are to store the results sequentially according to the number of closing actions, and the stored content includes the result value, closing action time, corresponding vertical temperature variation and sensitivity deviation, with a storage period of not less than 3 years, to facilitate subsequent trend analysis and historical data traceability.

[0036] Specifically, the deployment of this invention relies on the existing switchgear cabinet structure, requiring no mechanical modification to the cabinet. A data acquisition and processing module is fixedly installed in the low-voltage instrument room of the switchgear, and the module has signal acquisition and preliminary calculation capabilities. A Hall current sensor is connected in series in the closing coil power supply circuit to acquire the closing coil current signal. A Hall current sensor of the same type is connected in series in the energy storage motor power supply circuit to acquire the energy storage motor current signal. Voltage transformers and current transformers are installed on the bus side and cable side of the primary main circuit of the switchgear, respectively, to acquire the transient voltage and transient current signals of the primary side. A platinum resistance temperature sensor is attached to the middle of the outer wall of the upper contact box facing the circuit breaker trolley, and a platinum resistance temperature sensor of the same specification is attached to the corresponding position in the lower contact box to acquire the temperature signals of the two contact boxes. The output terminals of all sensors are connected to the data acquisition and processing module, which is equipped with a synchronous clock unit to ensure that the acquisition time base of all signals is consistent. When the switchgear receives a closing operation command, the synchronous clock unit triggers the acquisition process, and completes the synchronous acquisition of all signals according to the preset time window. After the data collection is completed, the module transmits the raw data to the background analysis unit. The background analysis unit completes the entire process calculation according to the preset algorithm. The entire data collection and processing process is executed automatically without manual intervention.

[0037] Specifically, this invention ultimately outputs a single-valued online mechanical monitoring result, with the result unit being milliseconds. This result characterizes the abnormal additional mechanical delay caused by the temperature coupling between the upper and lower contact boxes of the switchgear, exceeding the equipment's healthy state. The background analysis unit automatically calculates and generates anomaly judgment thresholds based on historical data from the equipment's healthy operating cycle. When the output result is below the threshold, it indicates that the structural state of the equipment's closing action is normal. When the output result is above the threshold, it indicates that the equipment has structural state changes caused by the temperature coupling between the upper and lower contact boxes. For example, the anomaly threshold generated under the healthy state of a 10 kV switchgear is 3 milliseconds. The output result of the first closing action of this switchgear is 1.1 milliseconds, which is below the threshold, indicating that the equipment's structural state remains stable. The output result of the second closing action of this switchgear is 4.2 milliseconds, which is above the threshold, indicating that the equipment has structural anomalies related to the temperature coupling between the upper and lower contact boxes. The output result can be displayed in real time on the local display screen of the switchgear, or it can be uploaded to the substation integrated monitoring platform via a communication link. At the same time, historical data is completely stored according to the closing action sequence to meet the needs of status traceability and long-term analysis.

[0038] It should be noted that this invention is applicable to online monitoring of the mechanical characteristics of indoor switchgear with voltage levels ranging from 10 kV to 35 kV; it can be applied to switchgear monitoring scenarios in urban power distribution substations; it can be applied to switchgear monitoring scenarios in self-owned power distribution rooms of industrial and mining enterprises; it can be applied to switchgear monitoring scenarios in power distribution rooms of commercial buildings; it can be applied to factory acceptance and post-commissioning status monitoring scenarios for switchgear in newly built substations; and it can also be applied to intelligent transformation and upgrading scenarios for existing switchgear in operation, covering the status monitoring needs of the entire life cycle of switchgear. This invention can realize continuous online monitoring of the mechanical characteristics of switchgear closing actions, replacing the traditional periodic offline testing method; it can identify mechanical time delay changes caused by temperature differences in the upper and lower structures of the switchgear, providing a reference basis for equipment status assessment; it can detect potential hazards related to cabinet structural abnormalities in advance, reducing the risk of power outages caused by sudden equipment failures; it simplifies the operation process of switchgear mechanical characteristic monitoring, reducing the workload of manual on-site testing; by storing monitoring data for a long time, it can form equipment status change trends, providing data support for switchgear operation and maintenance decisions; it adapts to the deployment needs of existing and newly built equipment, improving the level of intelligence in switchgear operation and management.

[0039] It should be noted that the interval and threshold sizes are set for ease of comparison. The size of the threshold depends on the amount of sample data and the base number set by those skilled in the art for each set of sample data, as long as it does not affect the proportional relationship between the parameter and the quantized value. Furthermore, the above formulas are all dimensionless calculations, and the formulas are derived from software simulations using a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0040] The embodiments of this example have been described above. However, this example is not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms based on the guidance of this example, and all of them are within the protection scope of this example.

Claims

1. An online monitoring system for the mechanical characteristics of a switchgear, characterized in that, include: The data acquisition module synchronously acquires the closing coil current, energy storage motor current, primary side transient voltage, primary side transient current, upper contact box temperature at the start of the action, and lower contact box temperature at the start of the action during the closing action. The energy storage input integral calculation module calculates the uniform temperature and vertical differential temperature based on the temperature of the upper and lower contact boxes, and performs integral calculation on the energy storage motor current to obtain the energy storage input integral. The electromagnetic release timing extraction module extracts the extreme points of the second derivative of the closing coil current as a function of time as the electromagnetic release timing. The structural propagation delay calculation module integrates the rate of change of the primary transient voltage and the rate of change of the primary transient current to construct a composite slope, extracts the extreme point of the composite slope as the actual engagement time, and uses the time difference between the actual engagement time and the electromagnetic release time as the structural propagation delay. The baseline delay calculation module constructs a baseline delay model by combining historical health samples, and calculates the baseline delay by substituting the average temperature and energy storage input integrals into the baseline delay model. The health baseline calculation module divides the difference between the structural transfer delay and the baseline delay by the vertical anisothermal effect to obtain the structural anisothermal sensitivity coefficient, and combines it with historical health samples to calculate the health baseline of the structural anisothermal sensitivity coefficient. The monitoring results output module calculates and outputs single-valued online mechanical monitoring results based on vertical temperature variation and the difference between the structural temperature variation sensitivity coefficient and the health baseline.

2. The online monitoring system for the mechanical characteristics of a switchgear according to claim 1, characterized in that, Synchronously collect the closing coil current, energy storage motor current, primary side transient voltage, primary side transient current, upper contact box temperature at the start of the operation, and lower contact box temperature at the start of the operation, including: Using the start time of the closing action as the time reference, a data window corresponding to the closing action is constructed; the data window is jointly determined by the start time of the action, the pre-acquisition duration, and the subsequent acquisition duration. The closing coil current, energy storage motor current, primary side transient voltage, and primary side transient current are synchronously collected within the data window, and it is ensured that the domains of the closing coil current, energy storage motor current, primary side transient voltage, and primary side transient current all fall within the data window. The temperature of the upper contact box and the temperature of the lower contact box at the start of the action are collected.

3. The online monitoring system for the mechanical characteristics of a switchgear according to claim 1, characterized in that, Based on the temperature of the upper and lower contact boxes, the uniform temperature and vertical differential temperature are calculated. The energy storage motor current is then integrated to obtain the energy storage input integral, including: Call the temperature of the upper contact box, the temperature of the lower contact box, and the current of the energy storage motor at the start of the action; The average temperature is calculated by taking the arithmetic mean of the upper contact box temperature and the lower contact box temperature at the start of the action. The difference between the temperature of the upper contact box and the temperature of the lower contact box at the start of the action is calculated to obtain the vertical differential temperature. Within the data window, determine the start and end times of the energy storage motor current associated with the closing action, and determine the integration interval based on the start and end times of the energy storage motor current; perform integration calculation on the energy storage motor current within the integration interval to obtain the energy storage input integral.

4. The online monitoring system for the mechanical characteristics of a switchgear according to claim 1, characterized in that, The extreme points of the second derivative of the closing coil current over time are extracted as the electromagnetic release moments, including: Call the closing coil current and data window; determine the energization start time corresponding to the start of the energization change segment of the closing coil current in the data window; calculate the second derivative of the closing coil current with respect to time and take the absolute value to construct the second derivative quantization function; Within the range after the energization start time, extract the time corresponding to the first local maximum point of the second derivative scalar function in time, and determine this time as the electromagnetic release time.

5. The online monitoring system for the mechanical characteristics of a switchgear according to claim 1, characterized in that, A composite slope is constructed by integrating the rate of change of the primary transient voltage and the rate of change of the primary transient current. The extreme point of the composite slope is extracted as the actual engagement moment. The time difference between the actual engagement moment and the electromagnetic release moment is used as the structural propagation delay, including: Call the primary side transient voltage, primary side transient current, data window, and electromagnetic release time; The rate of change of the primary transient voltage and the rate of change of the primary transient current are obtained by taking the first derivative of the primary transient voltage and the primary transient current with respect to time. The scaling factor is constructed by comparing the root mean square value of the rate of change of the primary transient voltage with the root mean square value of the rate of change of the primary transient current within the data window. By using a scaling factor, the rate of change of the primary transient voltage and the rate of change of the primary transient current are fused together to construct a composite slope; Within the time range after the electromagnetic release, extract the moment corresponding to the first local maximum of the composite slope in time, and determine this moment as the actual moment of rigidity. The structural propagation delay is calculated by subtracting the actual moment of engagement from the moment of electromagnetic release.

6. The online monitoring system for the mechanical characteristics of a switchgear according to claim 1, characterized in that, A baseline latency model is constructed by combining historical health samples. The baseline latency is calculated by substituting the integrals of the average temperature and energy storage inputs into the baseline latency model, including: The isothermal, energy storage input integral, and structural propagation delay are called, and the isothermal, energy storage input integral, and structural propagation delay corresponding to the historical healthy samples are introduced. Based on historical health samples, the baseline delay model input and output terms corresponding to the historical health samples are constructed. The baseline delay model input terms corresponding to the historical health samples consist of a constant term, the mean temperature corresponding to the historical health samples, and the reciprocal of the energy storage input integral corresponding to the historical health samples. The baseline delay model output terms corresponding to the historical health samples are the structural transfer delay corresponding to the historical health samples. The baseline delay model inputs corresponding to all historical health samples are combined to form an input matrix, and the baseline delay model outputs corresponding to all historical health samples are combined to form an output vector. The baseline delay model parameters are then calculated. The baseline delay model parameters include constant parameters, model parameters corresponding to the average temperature, and model parameters corresponding to the inverse of the energy storage input integral. The baseline time delay model input term corresponding to the closing action is constructed based on the temperature and energy storage input integral; wherein, the baseline time delay model input term corresponding to the closing action consists of a constant term, the temperature and the reciprocal of the energy storage input integral; The baseline delay is obtained by linearly combining the input terms of the baseline delay model corresponding to the closing action with the baseline delay model parameters.

7. The online monitoring system for the mechanical characteristics of a switchgear according to claim 1, characterized in that, The structural anisothermal sensitivity coefficient is obtained by dividing the difference between the structural transfer delay and the baseline delay by the vertical anisothermal value. A health baseline for the structural anisothermal sensitivity coefficient is then calculated by combining this baseline with historical healthy samples, including: The structure propagation delay, baseline delay, and vertical temperature variation are invoked, and the structure propagation delay, baseline delay, and vertical temperature variation corresponding to the historical healthy samples are introduced. The delay difference is obtained by calculating the difference between the structure propagation delay and the baseline delay. Divide the time delay difference by the vertical temperature difference to obtain the structural temperature sensitivity coefficient; The difference between the structure transmission delay corresponding to the historical health sample and the baseline delay corresponding to the historical health sample is calculated to obtain the delay difference corresponding to the historical health sample. Divide the time delay difference corresponding to the historical healthy sample by the vertical anisothermia corresponding to the historical healthy sample to obtain the structural anisothermia sensitivity coefficient corresponding to the historical healthy sample. Set the number of historical healthy samples to participate in the calculation, and average the structural isothermal sensitivity coefficients corresponding to all historical healthy samples to obtain the health benchmark of structural isothermal sensitivity coefficients.

8. The online monitoring system for the mechanical characteristics of a switchgear according to claim 1, characterized in that, Based on vertical temperature variation and the difference between the structural temperature variation sensitivity coefficient and the health baseline, a single-valued online mechanical monitoring result is calculated and output, including: Call upon the health benchmarks of vertical isothermal and structural isothermal sensitivity coefficients; The difference between the structural isothermal sensitivity coefficient and the health baseline is obtained by subtracting the structural isothermal sensitivity coefficient from the health baseline. The absolute value of vertical temperature variation is taken, and the absolute value of the difference between the structural temperature variation sensitivity coefficient and the health baseline is taken. The absolute values ​​of the two are multiplied to obtain the single-valued mechanical online monitoring result and output it.

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