A method for diagnosing performance of a molded case circuit breaker

Abstract

The application provides a method for diagnosing the performance of a molded case circuit breaker, belonging to the technical field of molded case circuit breakers, comprising the following steps: S1: collecting the gas temperature data of the exhaust port of the arc extinguishing chamber in real time through a temperature sensor; S2: extracting temperature characteristic parameters based on the temperature data; S3: based on the preset hierarchical threshold system of the temperature characteristic parameters, combining the multi-feature cross-validation logic of each performance dimension, respectively comprehensively judging the contact performance, arc extinguishing chamber performance and breaking capacity of the molded case circuit breaker; S4: generating corresponding hierarchical fault early warning information or performance evaluation reports according to the performance judgment results. The application collects the gas temperature data of the exhaust port of the arc extinguishing chamber, extracts multi-dimensional temperature characteristic parameters, combines the hierarchical threshold system and the multi-feature cross-validation logic, realizes direct and accurate diagnosis of the contact performance, arc extinguishing chamber performance and breaking capacity, and solves the problems of early warning lag and high misjudgment rate caused by the dependence on indirect indexes in the prior art.

Description

Technical Field

[0001] This invention relates to the field of molded case circuit breaker technology, and in particular to a method for diagnosing the performance of molded case circuit breakers. Background Technology

[0002] Molded case circuit breakers (MCCBs) are core protection devices in industrial power distribution and building electrical systems. The reliability of their contact performance, arc-extinguishing chamber performance, and breaking capacity directly impacts the safe operation of the power distribution system. In practical applications, circuit breakers frequently need to interrupt fault currents such as overloads and short circuits. After long-term use, they are prone to problems such as contact wear, arc-extinguishing chamber grid erosion, and decreased breaking speed. Existing technologies mostly rely on indirect indicators such as the number of breaking actions and operating time to judge performance, which cannot reflect the core state during the arc-extinguishing process in real time. This results in delayed fault warnings and a high false alarm rate, making it difficult to meet the needs of power distribution systems for accurate equipment status monitoring. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a method for diagnosing the performance of molded case circuit breakers.

[0004] The technical solution adopted by this invention is as follows: This application provides a performance diagnosis method for molded case circuit breakers, including the following steps: S1: A temperature sensor is installed at the outlet of the arc-extinguishing chamber of the molded case circuit breaker, and the gas temperature data of the outlet of the arc-extinguishing chamber is collected in real time through the temperature sensor; S2: Temperature feature parameters are extracted based on the temperature data, the temperature feature parameters including temperature value, temperature change rate, temperature duration and temperature fluctuation pattern; S3: Based on a preset graded threshold system of temperature feature parameters, combined with multi-feature cross-validation logic of each performance dimension, the contact performance, arc-extinguishing chamber performance and breaking capacity of the molded case circuit breaker are comprehensively judged, the specific judgment logic is as follows: Contact performance judgment: Based on the deviation of the temperature value from the normal threshold range... The following parameters are considered: S1: Contact performance degradation or fault; S2: The performance of the arc-extinguishing chamber is assessed based on the matching degree between the temperature change rate and the normal drop rate threshold, the deviation of the temperature duration from the normal threshold, and whether a secondary peak appears in the temperature fluctuation pattern. S3: Breaking capacity is assessed based on the circuit breaker's preset current level operating conditions, the adaptability of the temperature value to the normal threshold under the corresponding preset current level, the rationality of the temperature duration, and the integrity of the temperature fluctuation pattern. S4: Based on the above performance assessment results, corresponding graded fault warning information or performance evaluation reports are generated.

[0005] In some embodiments, temperature-current linkage compensation is further included, which includes: setting a current sensor in the main circuit of the molded case circuit breaker, and synchronously collecting the breaking current data of the main circuit through the current sensor and the temperature sensor; establishing a dynamic correlation model between breaking current and temperature characteristic parameters, and dynamically calculating the normal threshold range of each temperature characteristic parameter based on the real-time collected breaking current data through a temperature-current linkage compensation algorithm, replacing the preset normal threshold range of temperature characteristic parameters in step S3, and synchronously updating the operating condition for breaking capacity judgment to the operating condition combined with the real-time collected breaking current.

[0006] In some embodiments, the dynamic correlation model between breaking current and temperature characteristic parameters is established as follows: a full-current-range breaking test is performed on the molded case circuit breaker, and sample data of temperature values, temperature change rates, temperature durations, and temperature fluctuation patterns corresponding to different breaking currents are collected; mathematical fitting or intelligent algorithm modeling is used to construct a quantitative correlation relationship between each temperature characteristic parameter and the breaking current, thus forming the dynamic correlation model.

[0007] In some embodiments, the mathematical fitting is a polynomial fitting, and the intelligent algorithm is a neural network algorithm. The correlation expression between each temperature characteristic parameter and the breaking current is obtained through the mathematical fitting or intelligent algorithm, and the normal threshold range of each temperature characteristic parameter is dynamically calculated based on the correlation expression.

[0008] In some embodiments, the temperature-current linkage compensation algorithm further includes a self-learning correction step: after accumulating a preset number of interruption operations, the real-time collected interruption current and temperature characteristic parameter data are compared with the initial dynamic correlation model for deviation; if the deviation exceeds the preset allowable range, the parameters of the dynamic correlation model are automatically corrected to maintain the long-term accuracy of the calculation of the normal threshold range of each temperature characteristic parameter.

[0009] In some embodiments, the graded threshold system includes temperature value graded thresholds, which include normal threshold ranges and fault thresholds; the specific judgment logic for contact performance is as follows: if the temperature value exceeds the normal threshold range but does not reach the fault threshold, and the temperature values ​​of multiple consecutive segments show a continuous upward trend, it is determined that the contact performance has deteriorated; if the temperature value reaches or exceeds the preset fault threshold, or the temperature fluctuation pattern shows multi-peak unstable characteristics, it is determined that the contact is faulty.

[0010] In some embodiments, the graded threshold system includes a temperature rate graded threshold and a temperature duration graded threshold; the temperature rate graded threshold includes a normal rate threshold and a fault rate threshold, and the temperature duration graded threshold includes a normal duration threshold and a fault duration threshold; the specific judgment logic for the arc-extinguishing chamber performance is as follows: if the temperature change rate is lower than the normal rate threshold and higher than the fault rate threshold, and the temperature duration exceeds the normal duration threshold but does not reach the fault duration threshold, and there is no secondary temperature peak, then it is determined that the arc-extinguishing chamber performance has degraded; if the temperature change rate reaches or is lower than the preset fault rate threshold, and the temperature duration reaches or exceeds the preset fault duration threshold, or the temperature fluctuation pattern shows a secondary peak, then it is determined that the arc-extinguishing chamber is faulty.

[0011] In some embodiments, the graded threshold system includes a temperature value graded threshold and a temperature duration graded threshold; the temperature value graded threshold includes a normal threshold range and a fault threshold, and the temperature duration graded threshold includes a normal duration threshold and a fault duration threshold; the specific judgment logic of the breaking capacity is as follows: combined with the circuit breaker's preset current level operating conditions, if the temperature value corresponding to the preset small overload current level exceeds the normal threshold range but does not reach the fault threshold, or the temperature value corresponding to the preset large short-circuit current level is lower than the normal threshold range but not lower than the fault threshold, then it is determined that the breaking capacity has degraded; if the temperature duration corresponding to the preset large short-circuit current level reaches or exceeds the preset fault duration threshold, and the temperature fluctuation pattern shows a second peak, then it is determined that the breaking capacity has failed.

[0012] In some embodiments, the graded threshold system includes a temperature value graded threshold and a temperature duration graded threshold; the temperature value graded threshold includes a dynamically calculated normal threshold range and a fault threshold, and the temperature duration graded threshold includes a dynamically calculated normal duration threshold and a fault duration threshold; the specific judgment logic of the breaking capacity is as follows: combining the breaking current conditions collected in real time, if the temperature value under the real-time small overload current condition exceeds the dynamically calculated normal threshold range but does not reach the fault threshold, or the temperature value under the real-time large short-circuit current condition is lower than the dynamically calculated normal threshold range but not lower than the fault threshold, then it is determined that the breaking capacity has degraded; if the temperature duration under the real-time large short-circuit current condition reaches or exceeds the dynamically calculated fault duration threshold, and the temperature fluctuation pattern shows a second peak, then it is determined that the breaking capacity has failed.

[0013] In some embodiments, the stability of the temperature fluctuation pattern is determined by a quantitative index, which includes a temperature fluctuation coefficient and a peak interval time. The temperature fluctuation coefficient is the ratio of the temperature peak value to the temperature mean value, and the peak interval time is the time difference between adjacent temperature peak values. If the temperature fluctuation coefficient exceeds a preset stability coefficient range, or the peak interval time is less than a preset minimum interval time, the temperature fluctuation pattern is determined to be unstable.

[0014] The beneficial effects of this invention are as follows: This invention collects gas temperature data by setting a temperature sensor at the outlet of the arc-extinguishing chamber, extracts multi-dimensional temperature feature parameters, and combines a graded threshold system with multi-feature cross-validation logic to achieve direct and accurate diagnosis of contact performance, arc-extinguishing chamber performance and breaking capacity, thus solving the problems of delayed early warning and high misjudgment rate caused by the reliance on indirect indicators in existing technologies. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0016] Figure 1 This is a schematic diagram of the molded case circuit breaker in this invention;

[0017] Figure 2 This is a cross-sectional view of the molded case circuit breaker in this invention;

[0018] Figure 3 This is a flowchart illustrating a performance diagnosis method for molded case circuit breakers according to the present invention.

[0019] Figure 4 This is a block diagram of the internal functional units of the processor in this invention;

[0020] Figure 5 This is an overall structural block diagram of a performance diagnostic system for molded case circuit breakers according to the present invention. Detailed Implementation

[0021] The following description provides specific application scenarios and requirements for this specification, intended to enable those skilled in the art to make and use the contents of this specification. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this specification. Therefore, this specification is not limited to the embodiments shown, but rather to the widest scope consistent with the claims.

[0022] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "longitudinal", "lateral", "radial", "length", "width", "thickness", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element or component to have a specific orientation, or to be constructed and operated in a specific orientation.

[0023] It should be noted that the terms "first," "second," and similar words do not indicate any order, quantity, or importance, but are only used to distinguish different components and should not be construed as limiting the embodiments of this application.

[0024] It should be noted that the terms "installation," "setup," "equipped with," "connection," and "connected" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral structures; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium, or internal connections between two devices, components, or parts.

[0025] It should be noted that the terms "in some embodiments," "exemplarily," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "in some embodiments," "exemplarily," or "for example" should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "in some embodiments," "exemplarily," and "for example" is intended to present related concepts in a specific manner, meaning that a particular feature, structure, or characteristic described in connection with an embodiment may include in at least one embodiment of this application. The appearance of the above terms in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0026] Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0027] Regarding the accompanying drawings of this application, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this specification. It should also be understood that the drawings are not necessarily drawn to scale.

[0028] Existing performance diagnostic methods for molded case circuit breakers rely on indirect indicators, such as the number of breaking actions and running time, which cannot reflect the core state of the arc extinguishing process in real time. This results in problems such as delayed early warning, high misjudgment rate, and poor adaptability to operating conditions.

[0029] Based on the above problems, this invention proposes a performance diagnosis method for molded case circuit breakers, as shown in Figures 1 to 5. This method can be applied to a performance diagnosis system that utilizes this method. The system includes a molded case circuit breaker 1 and a processor. The molded case circuit breaker 1 includes a moving contact 2, a stationary contact 3, an arc-extinguishing chamber 4, and an operating mechanism 5. The moving contact 2 and the stationary contact 3 are disconnected within the arc-extinguishing chamber 4. An air outlet 6 is provided at the end of the arc-extinguishing chamber 4 furthest from the moving contact, and a temperature sensor 7 is installed at the air outlet. A current sensor is installed on the main circuit of the molded case circuit breaker. Both the temperature sensor 7 and the current sensor are connected to the processor. The processor can be embedded within the molded case circuit breaker or installed on a monitoring platform and connected to the data transmission module of the molded case circuit breaker. The processor incorporates a temperature feature parameter extraction unit 8, a hierarchical threshold calculation unit 9, a dynamic correlation model construction unit 10, a multi-feature cross-validation unit 11, a compensation correction unit 12, a self-learning correction unit 13, and a predictive maintenance suggestion generation unit 14.

[0030] Preferably, the temperature sensor can be a non-contact infrared temperature sensor. An installation hole is opened on the side wall of the arc-extinguishing chamber outlet, and the sensor is fixed in the hole by a threaded locking structure. The probe extends into the outlet and directly contacts the core area of ​​the arc airflow, avoiding temperature attenuation caused by airflow diffusion.

[0031] Preferably, the current sensor and the temperature sensor synchronously collect the main circuit interruption current data, and their sampling frequencies are kept consistent to ensure the time synchronization of the interruption current and temperature data.

[0032] Preferably, the signal acquisition circuit of the temperature sensor is equipped with an electromagnetic shielding filter module. The electromagnetic shielding filter module adopts a combination structure of shielded twisted pair cable and RC low-pass filter to perform electromagnetic interference filtering on the acquired temperature data.

[0033] Preferably, the system is further equipped with an ambient temperature sensor to collect the operating ambient temperature of the circuit breaker.

[0034] The diagnostic methods applied to the above systems include the following steps:

[0035] S1: The gas temperature data at the outlet of the arc-extinguishing chamber is collected in real time by the temperature sensor;

[0036] S2: Extract temperature feature parameters based on the temperature data. These parameters include temperature value, temperature change rate, temperature duration, and temperature fluctuation pattern. The temperature value represents the peak and average temperatures within the acquisition period. The peak temperature directly reflects the highest energy intensity of the arc combustion, while the average temperature mitigates the impact of transient interference on the diagnostic results. The temperature change rate is the rate at which the temperature drops from the peak to the average temperature. This rate is positively correlated with the arc energy dissipation efficiency, directly reflecting the energy extraction capability of the arc extinguishing system. The temperature duration is the cumulative time the temperature is above a preset reference temperature, corresponding to the equivalent duration of actual arc combustion. A longer duration indicates greater difficulty in extinguishing the arc. The stability of the temperature fluctuation pattern is determined by quantitative indicators, including the temperature fluctuation coefficient and peak interval time. The temperature fluctuation coefficient is the ratio of the peak temperature to the average temperature, and the peak interval time is the time difference between adjacent temperature peaks. If the temperature fluctuation coefficient exceeds a preset stability coefficient range, or the peak interval time is less than a preset minimum interval time, the temperature fluctuation pattern is determined to be unstable.

[0037] This allows for a comprehensive capture of temperature change characteristics during the arc extinguishing process, providing multi-dimensional data support for performance diagnosis. Compared to monitoring a single temperature parameter, the accuracy of diagnosis is significantly improved.

[0038] S3: Based on a preset temperature characteristic parameter grading threshold system, combined with multi-feature cross-validation logic for each performance dimension, the contact performance, arc-extinguishing chamber performance, and breaking capacity of the molded case circuit breaker are comprehensively judged. The grading threshold system includes temperature numerical grading thresholds, temperature rate grading thresholds, and temperature duration grading thresholds. All grading thresholds are calibrated through laboratory full-current-range breaking tests. The temperature numerical grading thresholds include normal threshold ranges and fault thresholds. The temperature rate grading thresholds include normal rate thresholds and fault rate thresholds. The temperature duration grading thresholds include normal duration thresholds and fault duration thresholds.

[0039] The specific judgment logic is as follows:

[0040] Contact performance assessment: Based on the deviation of the temperature value from the normal threshold range, the trend of temperature value changes during continuous breaking, and the stability of temperature fluctuation pattern, it is determined whether the contact performance has deteriorated or is faulty. This is mainly because contact wear or poor contact will lead to increased contact resistance, and the arc energy during breaking will increase accordingly, which is directly reflected in the temperature rise. Contact wear is a gradual degradation, so the temperature during continuous breaking will show a continuous upward trend. Poor contact will lead to intermittent contact of the contacts, repeated generation and extinguishing of the arc, corresponding to the multi-peak characteristics of the temperature fluctuation pattern.

[0041] For example, if the temperature value exceeds the normal threshold range but does not reach the fault threshold, and the temperature values ​​of multiple consecutive breaks show a continuous upward trend, it is determined that the contact performance has deteriorated; if the temperature value reaches or exceeds the preset fault threshold, or the temperature fluctuation pattern shows a multi-peak unstable characteristic, it is determined that the contact has failed. Arc-extinguishing chamber performance judgment: Based on the matching degree between the temperature change rate and the normal fallback rate threshold, the deviation of the temperature duration from the normal threshold, and whether a secondary peak appears in the temperature fluctuation pattern, it is determined whether the arc-extinguishing chamber performance has deteriorated or has a fault. This is mainly because the core function of the arc-extinguishing chamber is to quickly extinguish the arc. Grid erosion and arc-extinguishing medium failure will lead to a decrease in arc-extinguishing efficiency and a prolonged arc duration, manifested as an increase in temperature duration and a decrease in the fallback rate of the temperature change rate. When arc extinguishing fails or the arc reignites, secondary arc energy will be released, reflected as a secondary peak in the temperature fluctuation pattern.

[0042] For example, the specific judgment logic of the arc-extinguishing chamber performance is as follows: if the temperature change rate is lower than the normal rate threshold and higher than the fault rate threshold, and the temperature duration exceeds the normal duration threshold but does not reach the fault duration threshold, and there is no secondary temperature peak, then it is determined that the arc-extinguishing chamber performance has degraded; if the temperature change rate reaches or is lower than the preset fault rate threshold, and the temperature duration reaches or exceeds the preset fault duration threshold, or the temperature fluctuation pattern shows a secondary peak, then it is determined that the arc-extinguishing chamber is faulty.

[0043] Breaking capacity assessment: Based on the circuit breaker's preset current rating conditions, and considering the compatibility of temperature values ​​with the corresponding preset current rating's normal threshold, the reasonableness of temperature duration, and the integrity of temperature fluctuation patterns, determine whether the breaking capacity has diminished or failed. This is mainly because breaking capacity is essentially the ability of the opening speed and arc-extinguishing capacity to match the current rating. An abnormally high temperature under a small overload current indicates insufficient opening speed, i.e., slow contact separation and accumulation of arc energy. A low temperature under a large short-circuit current indicates that the arc-extinguishing chamber has not fully participated in arc extinguishing, possibly resulting in incomplete breaking and the arc not fully entering the arc-extinguishing chamber. A prolonged temperature duration and secondary peak under a large short-circuit current indicate that the arc cannot be extinguished quickly, and the breaking capacity can no longer match the current rating.

[0044] For example, the specific judgment logic of the breaking capacity is as follows: combined with the preset current level operating conditions of the circuit breaker, if the temperature value corresponding to the preset small overload current level exceeds the normal threshold range but does not reach the fault threshold, or the temperature value corresponding to the preset large short-circuit current level is lower than the normal threshold range but not lower than the fault threshold, it is determined that the breaking capacity is degraded; if the temperature duration corresponding to the preset large short-circuit current level reaches or exceeds the preset fault duration threshold, and the temperature fluctuation pattern shows a second peak, it is determined that the breaking capacity is failed.

[0045] This multi-feature cross-validation logic can avoid misjudgment based on a single feature and ensure the reliability of the diagnostic results.

[0046] S4: Based on the above performance judgment results, generate corresponding graded fault warning information or performance evaluation reports.

[0047] In some embodiments, due to the significant differences in arc energy under different breaking currents, the arc energy of the short-circuit current is much greater than that of the overload current. A fixed threshold can easily lead to misjudging normal high temperatures as faults during high-current breaking and missing abnormal high temperatures during low-current breaking. A dynamic threshold can achieve accurate adaptation to different current conditions. Therefore, temperature-current linkage compensation is added, which includes: synchronously collecting main circuit breaking current data through the current sensor and temperature sensor; establishing a dynamic correlation model between breaking current and temperature characteristic parameters; and dynamically calculating the normal threshold range of each temperature characteristic parameter based on the real-time collected breaking current data using a temperature-current linkage compensation algorithm, replacing the preset normal threshold range of temperature characteristic parameters in step S3. The operating condition for judging breaking capacity is synchronously updated to combine the breaking current operating condition collected in real time.

[0048] Specifically, in step S3, the temperature value grading threshold includes a dynamically calculated normal threshold range and a fault threshold, and the temperature duration grading threshold includes a dynamically calculated normal duration threshold and a fault duration threshold. The breaking capacity judgment logic is changed to: combining the real-time collected breaking current conditions, if the temperature value under the real-time small overload current condition exceeds the dynamically calculated normal threshold range but does not reach the fault threshold, or the temperature value under the real-time large short-circuit current condition is lower than the dynamically calculated normal threshold range but not lower than the fault threshold, then it is determined that the breaking capacity has decayed; if the temperature duration under the real-time large short-circuit current condition reaches or exceeds the dynamically calculated fault duration threshold, and the temperature fluctuation pattern shows a second peak, then it is determined that the breaking capacity has failed.

[0049] This allows the method to adapt to different breaking current conditions, avoid misjudgments caused by fixed thresholds, and significantly improve the adaptability of the method to different operating conditions, especially suitable for power distribution scenarios with large current fluctuation ranges.

[0050] In some embodiments, the dynamic correlation model between breaking current and temperature characteristic parameters is established as follows: a full-current-range breaking test is performed on the molded case circuit breaker, and sample data of temperature values, temperature change rates, temperature durations, and temperature fluctuation patterns corresponding to different breaking currents are collected; mathematical fitting or intelligent algorithm modeling is used to construct a quantitative correlation relationship between each temperature characteristic parameter and the breaking current, forming the dynamic correlation model. The mathematical fitting is a polynomial fitting, and the intelligent algorithm is a neural network algorithm. The correlation expression between each temperature characteristic parameter and the breaking current is obtained through the mathematical fitting or intelligent algorithm, and the normal threshold range of each temperature characteristic parameter is dynamically calculated based on the correlation expression. Polynomial fitting has the advantages of simple calculation and strong real-time performance, making it suitable for low-cost embedded scenarios; neural network algorithms have higher fitting accuracy, can adapt to complex nonlinear correlation relationships, and meet high-precision diagnostic requirements.

[0051] In some embodiments, the temperature-current linkage compensation algorithm further includes a self-learning correction step: after accumulating a preset number of disconnection operations, the real-time collected disconnection current and temperature characteristic parameter data are compared with the initial dynamic correlation model to check for deviations; if the deviation exceeds a preset allowable range, the parameters of the dynamic correlation model are automatically corrected to maintain the long-term accuracy of the calculation of the normal threshold range of each temperature characteristic parameter. This is mainly because circuit breakers undergo gradual changes such as contact wear and natural degradation of arc-extinguishing chamber performance after long-term use, and the initial model cannot adapt to these changes. Self-learning correction can realize the dynamic updating of model parameters and ensure long-term diagnostic accuracy.

[0052] Furthermore, the self-learning correction step also includes fault risk weight allocation: differentiated weights are assigned to deviation data in different performance dimensions, with deviation weights corresponding to contact faults and arc-extinguishing chamber faults being higher than those corresponding to performance degradation; the model correction is triggered based on the weighted sum of deviations, improving the calibration sensitivity of parameters related to serious faults and ensuring diagnostic accuracy during long-term use. This is mainly because contact faults and arc-extinguishing chamber faults directly threaten the safety of the power distribution system, and the diagnostic accuracy of these faults must be prioritized, thus assigning them higher weights to avoid missing serious faults due to model bias.

[0053] In some embodiments, to address the impact of electromagnetic interference and ambient temperature drift on monitoring data, a joint compensation mechanism for electromagnetic interference and ambient temperature is also included: electromagnetic interference filtering is applied to the collected temperature data using an electromagnetic shielding filter module; the operating ambient temperature of the circuit breaker is collected using an ambient temperature sensor, and based on the correlation between the ambient temperature and the outlet temperature of the arc-extinguishing chamber, environmental baseline correction is applied to the temperature characteristic parameters to eliminate the influence of ambient temperature drift. This is primarily because the circuit breaker generates strong electromagnetic pulses when it breaks, which can easily lead to temperature signal distortion; and large fluctuations in ambient temperature in outdoor or industrial settings can superimpose on the monitored temperature, both of which can cause temperature data distortion. This joint compensation mechanism can effectively resist electromagnetic interference and ambient temperature changes in industrial settings, ensuring the authenticity of temperature characteristic parameters and providing a reliable data foundation for accurate diagnosis.

[0054] In some embodiments, the temperature-current linkage compensation algorithm further includes breaking current mutation identification and threshold adaptive adjustment: real-time monitoring of the breaking current change rate; if the current change rate exceeds a preset mutation threshold, it is determined to be a sudden short-circuit fault; at this time, the fault threshold for temperature value and the fault threshold for temperature duration are automatically increased to avoid misjudgment under sudden large current, while shortening the response time of temperature data acquisition, improving the ability to quickly capture sudden faults, and ensuring diagnostic reliability under extreme operating conditions. This is mainly because the current rise rate of a sudden short-circuit fault is extremely fast, and the arc energy surges instantaneously; if conventional thresholds are used, it is easy to misjudge it as a fault; at the same time, sudden faults require rapid response, and shortening the acquisition response time can capture fault characteristics in a timely manner.

[0055] In some embodiments, the graded fault warning information includes predictive maintenance suggestions, specifically: based on the performance judgment results of multiple consecutive segments, a performance degradation trend curve is fitted, for example using linear regression fitting, to calculate the estimated remaining lifespan of each performance dimension from the current state to the fault state; graded maintenance suggestions are generated based on the estimated remaining lifespan, including three categories: immediate maintenance, short-term maintenance, and periodic inspection, wherein immediate maintenance is triggered when the estimated remaining lifespan is less than a preset critical lifespan. Traditional diagnostics can only detect faults, while predictive maintenance can predict lifespan, helping users plan maintenance in advance, avoiding power distribution system outages caused by sudden equipment failures, and reducing operation and maintenance costs. This design provides end-to-end support from fault warning to maintenance guidance, helping users plan maintenance in advance, avoiding power distribution system outages caused by sudden equipment failures, and reducing operation and maintenance costs.

[0056] The working principle of this embodiment is as follows: When the molded case circuit breaker trips, the temperature sensor and current sensor simultaneously start data acquisition. The temperature sensor collects the gas temperature data at the outlet of the arc-extinguishing chamber, and the current sensor collects the main circuit tripping current data. The collected data is transmitted to the embedded processing module in real time. The temperature feature parameter extraction unit of the embedded processing module processes the temperature data and extracts four types of feature parameters: temperature value, temperature change rate, temperature duration, and temperature fluctuation pattern. If a current sensor is configured, the dynamic correlation model construction unit calls the dynamic correlation model and calculates the dynamic grading threshold through the temperature-current linkage compensation algorithm; otherwise, a preset grading threshold is used. The multi-feature cross-validation unit judges the contact performance, arc-extinguishing chamber performance, and tripping capacity based on the grading threshold and multi-feature cross-validation logic. At the same time, the electromagnetic interference and ambient temperature joint compensation mechanism corrects the data, and the tripping current mutation identification function adapts to extreme working conditions. Finally, the predictive maintenance suggestion generation unit generates graded fault warning information and maintenance suggestions, which are uploaded to the monitoring platform through the data transmission module to complete one performance diagnosis process. After accumulating a preset number of trips, the self-learning correction unit automatically triggers model correction to ensure long-term diagnostic accuracy.

[0057] In summary, after reading this detailed disclosure, those skilled in the art will understand that the foregoing detailed disclosure is presented by way of example only and is not restrictive. Although not explicitly stated herein, those skilled in the art will understand that the requirements of this application encompass various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are intended to be made by this application and are within the spirit and scope of the exemplary embodiments of this application.

[0058] Furthermore, it should be understood that in the foregoing description of the embodiments of this application, various features are combined in a single embodiment, drawing, or description for the purpose of simplifying the understanding of a feature. However, this does not mean that the combination of these features is necessary, and those skilled in the art may readily identify some of the devices as separate embodiments when reading this application. That is, the embodiments in this application can also be understood as an integration of multiple sub-embodiments. It is also valid when each sub-embodiment contains fewer than all the features of a single foregoing disclosed embodiment.

[0059] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the embodiments of this application. Other modified embodiments are also within the scope of this application. Therefore, the embodiments disclosed herein are merely examples and not limitations. Those skilled in the art can adopt alternative configurations to implement the applications in this application based on the embodiments in this application. Therefore, the embodiments of this application are not limited to the embodiments precisely described in the application.

Claims

1. A molded case circuit breaker performance diagnostic method characterized by, The method comprises the following steps: S1: A temperature sensor is arranged at the gas outlet of the arc extinguishing chamber of the molded case circuit breaker, and the temperature data of the gas outlet of the arc extinguishing chamber is collected in real time through the temperature sensor; S2: A temperature characteristic parameter is extracted based on the temperature data, and the temperature characteristic parameter comprises a temperature value, a temperature change rate, a temperature duration, and a temperature fluctuation form; S3: Based on a preset hierarchical threshold system of the temperature characteristic parameter, and in combination with a multi-feature cross-verification logic of each performance dimension, the contact performance, the arc extinguishing chamber performance, and the breaking capacity of the molded case circuit breaker are comprehensively judged, and the specific judgment logic is as follows: contact performance judgment: whether the contact performance is attenuated or has a fault is determined according to the deviation relationship between the temperature value and the normal threshold range, the change trend of the temperature value in the continuous breaking process, and the stability of the temperature fluctuation form; arc extinguishing chamber performance judgment: whether the arc extinguishing chamber performance is attenuated or has a fault is determined according to the matching degree between the temperature change rate and the normal falling rate threshold, the deviation degree between the temperature duration and the normal threshold, and whether a second peak value appears in the temperature fluctuation form; breaking capacity judgment: whether the breaking capacity is attenuated or invalid is determined according to the adaptability between the temperature value and the corresponding preset current level under the normal threshold, the rationality of the temperature duration, and the integrity of the temperature fluctuation form in combination with the preset current level working condition of the circuit breaker; S4: According to the performance judgment result, corresponding hierarchical fault early warning information or performance evaluation report is generated; and temperature-current linkage compensation is further included, which comprises: a current sensor is arranged at the main circuit of the molded case circuit breaker, and the main circuit breaking current data is synchronously collected through the current sensor and the temperature sensor; A breaking current and temperature characteristic parameter dynamic correlation model is established, and the normal threshold range of each temperature characteristic parameter is dynamically calculated through a temperature-current linkage compensation algorithm based on the real-time collected breaking current data, so as to replace the preset temperature characteristic parameter normal threshold range in step S3, and the working condition of the breaking capacity judgment is updated in combination with the real-time collected breaking current working condition.

2. The method of claim 1, wherein the method further comprises: The establishment mode of the breaking current and temperature characteristic parameter dynamic correlation model is as follows: A full-current interval breaking test is performed on the molded case circuit breaker, and sample data of the temperature value, the temperature change rate, the temperature duration, and the temperature fluctuation form corresponding to different breaking currents is collected; A mathematical fitting or intelligent algorithm modeling mode is adopted to construct a quantitative correlation between each temperature characteristic parameter and the breaking current, and the dynamic correlation model is formed.

3. The method of claim 2, wherein: The mathematical fitting is polynomial fitting, and the intelligent algorithm is a neural network algorithm, and the correlation expression between each temperature characteristic parameter and the breaking current is obtained through the mathematical fitting or intelligent algorithm, and the dynamic calculation of the normal threshold range of each temperature characteristic parameter is realized based on the correlation expression.

4. The method of claim 1, wherein, The temperature-current linkage compensation algorithm further comprises a self-learning correction link: After a preset number of breaking operations, the deviation of the real-time collected breaking current and temperature characteristic parameter data and the initial dynamic correlation model is compared; If the deviation exceeds a preset allowable range, the parameters of the dynamic correlation model are automatically corrected to maintain the long-term accuracy of the calculation of the normal threshold range of each temperature characteristic parameter.

5. The method of claim 1, wherein the method further comprises: The hierarchical threshold system comprises temperature value hierarchical thresholds, and the temperature value hierarchical thresholds comprise a normal threshold range and a fault threshold; The specific determination logic of the contact performance is that if the temperature value exceeds the normal threshold range and does not reach the fault threshold, and the temperature values of continuous multiple breakages show a continuous rising trend, the contact performance is determined to be attenuated; If the temperature value reaches or exceeds the preset fault threshold, or the temperature fluctuation form shows a multi-peak unstable feature, the contact is determined to be faulty.

6. The method of claim 1, wherein the method further comprises: The hierarchical threshold system comprises temperature rate hierarchical thresholds and temperature duration hierarchical thresholds; the temperature rate hierarchical thresholds comprise a normal rate threshold and a fault rate threshold, and the temperature duration hierarchical thresholds comprise a normal duration threshold and a fault duration threshold; The specific determination logic of the arc chamber performance is that if the temperature change rate is lower than the normal rate threshold and higher than the fault rate threshold, and the temperature duration exceeds the normal duration threshold and does not reach the fault duration threshold, and there is no secondary temperature peak, the arc chamber performance is determined to be attenuated; if the temperature change rate reaches or is lower than the preset fault rate threshold, and the temperature duration reaches or exceeds the preset fault duration threshold, or the temperature fluctuation form shows a secondary peak, the arc chamber is determined to be faulty.

7. The method of claim 1, wherein the method further comprises: The hierarchical threshold system comprises temperature value hierarchical thresholds and temperature duration hierarchical thresholds; the temperature value hierarchical thresholds comprise a normal threshold range and a fault threshold, and the temperature duration hierarchical thresholds comprise a normal duration threshold and a fault duration threshold; The specific determination logic of the breaking capacity is that in combination with a preset current level working condition of the circuit breaker, if the temperature value corresponding to a preset small overload current level exceeds the normal threshold range and does not reach the fault threshold, or the temperature value corresponding to a preset large short-circuit current level is lower than the normal threshold range and does not reach the fault threshold, the breaking capacity is determined to be attenuated; If the temperature duration corresponding to the preset large short-circuit current level reaches or exceeds the preset fault duration threshold, and the temperature fluctuation form shows a secondary peak, the breaking capacity is determined to be invalid.

8. The method of claim 1, wherein: The hierarchical threshold system comprises temperature value hierarchical thresholds and temperature duration hierarchical thresholds; the temperature value hierarchical thresholds comprise a dynamically calculated normal threshold range and a fault threshold, and the temperature duration hierarchical thresholds comprise a dynamically calculated normal duration threshold and a fault duration threshold; The specific determination logic of the breaking capacity is that in combination with a real-time collected breaking current working condition, if the temperature value under a real-time small overload current working condition exceeds the dynamically calculated normal threshold range and does not reach the fault threshold, or the temperature value under a real-time large short-circuit current working condition is lower than the dynamically calculated normal threshold range and does not reach the fault threshold, the breaking capacity is determined to be attenuated; if the temperature duration under the real-time large short-circuit current working condition reaches or exceeds the dynamically calculated fault duration threshold, and the temperature fluctuation form shows a secondary peak, the breaking capacity is determined to be invalid.

9. The method of claim 1, wherein the method further comprises: The stability of the temperature fluctuation mode is determined by a quantitative index, and the quantitative index comprises a temperature fluctuation coefficient and a peak interval time; wherein the temperature fluctuation coefficient is a ratio of a temperature peak value to a temperature mean value, and the peak interval time is a time difference between adjacent temperature peak values; if the temperature fluctuation coefficient exceeds a preset stable coefficient range or the peak interval time is less than a preset minimum interval time, it is determined that the temperature fluctuation mode is unstable.

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