Intelligent circuit breaker state detection method based on current characteristic analysis

Abstract

The invention relates to the technical field of data processing, in particular to an intelligent circuit breaker state detection method based on current characteristic analysis, and the method comprises the steps: obtaining an original coil current sequence of a to-be-detected circuit breaker, and automatically positioning a current sag sequence corresponding to the movement of an iron core, obtaining a current waveform complexity factor of the movement stage of the iron core based on the fluctuation characteristics and the duration of the current sag sequence, calculating the modal number of variational mode decomposition based on the current waveform complexity factor, carrying out variational mode decomposition on the current sag sequence, and extracting a high-frequency component as a mechanical friction characteristic component, based on the mechanical friction characteristic component, obtaining a mechanical friction factor of the iron core in a motion stage; and on the basis of the mechanical friction factor and the current waveform complexity factor in the iron core motion stage, the mechanical stagnation risk value is obtained to judge the state of the circuit breaker, and the accuracy of mechanical fault diagnosis of the circuit breaker is improved.

Description

Technical Field

[0001] This invention relates to the field of data processing technology. More specifically, this invention relates to a method for detecting the condition of an intelligent circuit breaker based on current characteristic analysis. Background Technology

[0002] Circuit breakers are key protection and control devices in power systems. Their operational reliability is directly related to the safe and stable operation of the power grid. During the operation of a circuit breaker, the current waveform flowing through the coil contains rich mechanical state information. A typical coil current waveform usually includes stages such as coil energization and excitation, core start-up, core movement, contact contact, and coil de-energization. During the core's movement, it cuts the magnetic field generated by the coil, thus generating a back electromotive force (EMF). This back EMF cancels out part of the power supply voltage, forcing the coil current to drop and forming a trough region in the current waveform. However, the core's movement speed and the mechanical resistance it experiences directly affect the magnitude and rate of change of the back EMF, which in turn changes the shape of the current trough. In other words, the shape of the trough region corresponding to the core's movement is closely related to the core's movement speed and the mechanical resistance it experiences. Therefore, analyzing the changing characteristics of the trough region can effectively diagnose mechanical faults in circuit breakers, such as corrosion and jamming of transmission components, friction, and obstruction by foreign objects.

[0003] It is known that mechanical faults in circuit breakers often generate high-frequency vibrations or transient impacts. Therefore, existing technologies for monitoring mechanical faults in circuit breakers typically utilize time-frequency analysis tools such as Variational Mode Decomposition (VMD) to extract the high-frequency components of the current. However, in existing VMD algorithm applications, the number of modes K is usually set to a fixed value. If a fixed number of modes is used to decompose the current signal, it may lead to under-decomposition (inability to completely extract high-frequency components) or over-decomposition (noise mixing), thereby affecting the accuracy of circuit breaker mechanical fault diagnosis. Furthermore, after obtaining the high-frequency components, the entire high-frequency components are usually subjected to indiscriminate mathematical processing. Then, the mechanical friction characteristics are mainly concentrated in the current trough region of the iron core during high-speed movement, and are most significant at the moment of maximum speed. Therefore, the analysis based on the entire high-frequency components will introduce a large amount of electromagnetic transient noise, which will drown out the weak early fault signals. Summary of the Invention

[0004] To address the issues of under-decomposition or over-decomposition when extracting high-frequency components of current based on variational mode decomposition due to the fixed number of modes, and the introduction of significant electromagnetic transient noise that overwhelms fault signals and affects the accuracy of circuit breaker mechanical fault diagnosis due to indiscriminate processing of the entire high-frequency component, this invention proposes a smart circuit breaker condition detection method based on current characteristic analysis. This method includes the following steps: Obtain the original coil current sequence of the circuit breaker under test; locate the current descent sequence corresponding to the core movement stage based on the original coil current sequence. Based on the fluctuation characteristics and duration of the current dip sequence, the current waveform complexity factor of the core motion stage is obtained; based on the current waveform complexity factor, the mode number of variational mode decomposition is obtained; based on the mode number of variational mode decomposition, variational mode decomposition is performed on the current dip sequence, and high-frequency components are extracted as mechanical friction feature components. Based on the velocity law of the iron core, the current data values ​​at each moment in the high-frequency friction component are weighted and summed to obtain the mechanical friction factor of the iron core during the motion stage. Based on the waveform complexity factor and the mechanical friction factor, a mechanical stall risk value is obtained; the health status of the circuit breaker is determined based on the mechanical stall risk value.

[0005] The innovation of this invention lies in the fact that by locating the current dip sequence and calculating the current waveform complexity factor, it achieves adaptive adjustment of the number of modes in the variational mode decomposition algorithm, solving the problem of over-decomposition or under-decomposition caused by the traditional fixed number of modes. At the same time, by using the core motion law to weight the high-frequency components, it effectively suppresses electromagnetic noise in non-critical motion stages, significantly improving the anti-interference capability and accuracy of circuit breaker mechanical fault diagnosis.

[0006] Preferably, obtaining the original coil current sequence of the circuit breaker under test includes: A Hall current sensor is connected to the control circuit of the opening / closing coil or the closing coil of the circuit breaker under test. The Hall current sensor is used to convert the current signal of the opening / closing coil or the closing coil into a voltage signal. The voltage signal is then input into a high-precision analog-to-digital converter with a sampling frequency of 1 millisecond / time to obtain the original coil current sequence of the circuit breaker under test.

[0007] Preferably, the current dip sequence corresponding to the core movement stage based on the original coil current sequence includes: Obtain the first-order difference value at each time step in the original coil current sequence. If the first-order difference value at time step t1 in the original coil current sequence is less than 0 and the first-order difference value at time step t1-1 is greater than 0, then record time step t1 as the starting point and the first starting point in the original coil current sequence as the target starting point. The current sequence after the target starting point is taken as the target current sequence. If the first-order difference value at time step t2 in the target current sequence is greater than 0 and the first-order difference value at time step t2-1 is less than 0, then record time step t2 as the ending point. The first ending point in the target current sequence is the target ending point. The sequence segment formed between the target starting point and the target ending point is recorded as the current trough sequence.

[0008] Locating the start and end points of the current trough allows for precise capture of core movement segments containing rich mechanical information, facilitating subsequent analysis of mechanical faults in the circuit breaker.

[0009] Preferably, the current waveform complexity factor is obtained by: The original coil current sequence of the circuit breaker in a healthy state is collected, and the current sag sequence of the circuit breaker in a healthy state is obtained. The number of times in the current sag sequence of the circuit breaker in a healthy state is used as the reference operating time of the circuit breaker in a healthy reference state, denoted as . ; , The current waveform complexity factor represents the phase of the iron core's movement. This represents the current data value at the (i+1)th moment in the current dip sequence; This represents the current data value at the i-th moment in the current dip sequence; This represents the maximum current data value in the current dip sequence; Represents the minimum current data value in the current dip sequence; || is the absolute value symbol. This represents the number of moments in the current dip sequence.

[0010] This provides an accurate physical basis for the adaptive selection of the number of modes.

[0011] Preferably, obtaining the number of modes in the variational mode decomposition includes: ; In the formula, Represents the number of modes in the variational mode decomposition; This represents the number of fundamental modes in the variational mode decomposition. Represents the adjustment sensitivity coefficient; The current waveform complexity factor represents the phase of the iron core's movement. Represents the logarithmic function, with restrictions The value of increases infinitely as the complexity factor of the current waveform increases. This represents the rounding function.

[0012] It can increase the number of modes when the fault is severe (high complexity) to facilitate the extraction of high-frequency components, and can limit the number of modes to prevent noise from mixing in when the condition is good.

[0013] Preferably, the variational mode decomposition of the current dip sequence based on the mode number of variational mode decomposition, and the extraction of high-frequency components as mechanical friction feature components, includes: Mode number based on variational mode decomposition The current dip sequence is subjected to variational mode decomposition to obtain the following results: For each IMF component, calculate its center frequency and select the IMF component with the highest center frequency as the mechanical friction characteristic component.

[0014] Preferably, obtaining the mechanical friction factor during the core movement phase includes: ; In the formula, The mechanical friction factor represents the stage of the iron core's movement; This represents the number of current data points in the high-frequency friction component. This represents the current data value at the i-th moment in the high-frequency friction component; This represents the current data value at the i-th moment in the current dip sequence; The number of time points in the current dip sequence is represented by exp(); exp() represents an exponential function with the natural constant as the base. Represents the preset decay rate; This represents the preset hyperparameters.

[0015] Preferably, obtaining the mechanical stall risk value includes: Obtain the current waveform complexity factor and mechanical friction factor of the circuit breaker in the core movement phase to obtain its health status. , This represents the risk value of mechanical stagnation; The mechanical friction factor represents the stage of the iron core's movement; The current waveform complexity factor represents the phase of the iron core's movement. Represents the weight of the mechanical friction factor; Represents the weight of the current waveform complexity factor; The mechanical friction factor of a circuit breaker during the core movement phase, representing its health status; The current waveform complexity factor of a circuit breaker during the core movement phase, representing its health status.

[0016] This improves the accuracy of subsequent circuit breaker fault monitoring.

[0017] Preferably, determining the health status of the circuit breaker based on the mechanical stall risk value includes: A preset risk threshold T1 is set. If the mechanical stall risk value is greater than or equal to the risk threshold, the circuit breaker has a mechanical fault. The system will issue an alarm and notify the staff to carry out immediate repairs.

[0018] Preferably, the current waveform complexity factor and mechanical friction factor of the circuit breaker during the core movement phase for obtaining its health status include: Based on the method of obtaining the current waveform complexity factor, the current waveform complexity factor of the current sag sequence of the circuit breaker in a healthy state is obtained, which is used as the current waveform complexity factor of the circuit breaker in a healthy state during the core movement stage; based on the method of obtaining the mechanical friction factor, the mechanical friction factor of the current sag sequence of the circuit breaker in a healthy state is obtained, which is used as the mechanical friction factor of the circuit breaker in a healthy state during the core movement stage.

[0019] The present invention has the following beneficial effects: First, by locating the current dip sequence and calculating the current waveform complexity factor, the present invention achieves adaptive adjustment of the number of modes in the variational mode decomposition algorithm, solving the problem of over-decomposition or under-decomposition caused by the traditional fixed number of modes; further, by weighted summing of the current data values ​​at each moment in the high-frequency friction component based on the core motion speed law, the mechanical friction factor of the core motion stage is obtained, which effectively suppresses electromagnetic noise in non-critical motion stages and significantly improves the anti-interference capability and accuracy of circuit breaker mechanical fault diagnosis; finally, based on the waveform complexity factor and the mechanical friction factor, the mechanical fault risk of the circuit breaker is comprehensively assessed, and the early fault signals of the circuit breaker can be identified. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the steps of a smart circuit breaker state detection method based on current characteristic analysis according to an embodiment of the present invention. Figure 2 A schematic diagram representing the automatic positioning of the original coil current waveform and current descent sequence; Figure 3 A schematic diagram of the weighted processing of characteristic components representing mechanical friction; Figure 4 This diagram illustrates how the status of a circuit breaker is determined based on the risk value of mechanical shutdown. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0022] Please see Figure 1 The diagram illustrates a flowchart of a smart circuit breaker state detection method based on current characteristic analysis according to an embodiment of the present invention. The method includes the following steps: S001. Obtain the original coil current sequence of the circuit breaker to be tested, and automatically locate the current dimpling sequence corresponding to the movement of the iron core based on the original coil current sequence.

[0023] It should be noted that the original coil current sequence during the operation of the circuit breaker under test is obtained, and the current sag sequence corresponding to the movement of the iron core is automatically located based on the changes in current data in the original coil current sequence.

[0024] In this embodiment of the invention, a Hall current sensor is connected to the control circuit of the opening / closing coil or the closing coil of the circuit breaker under test. The Hall current sensor is used to convert the current signal of the opening / closing coil or the closing coil into a voltage signal. The voltage signal is then input into a high-precision analog-to-digital converter with a sampling frequency of 1 millisecond / time to obtain the original coil current sequence of the circuit breaker under test. It should be noted that during the core movement phase, the back electromotive force causes the current waveform to exhibit a slope that changes from positive to negative and then back to positive, such as... Figure 2 As shown, this embodiment uses the first-order difference of the original coil current sequence to locate the current dip sequence corresponding to the core movement.

[0025] In this embodiment of the invention, the first-order difference value at each moment in the original coil current sequence is obtained; If the first-order difference value at time t1 in the original coil current sequence is less than 0 and the first-order difference value at time t1-1 is greater than 0, then time t1 is recorded as the starting point; the first starting point in the original coil current sequence is recorded as the target starting point. The current sequence following the target starting point is taken as the target current sequence. If the first difference value at time t2 in the target current sequence is greater than 0 and the first difference value at time t2-1 is less than 0, then time t2 is recorded as the termination point. The first termination point in the target current sequence is taken as the target termination point. The sequence segment formed between the target starting point and the target termination point is recorded as the current trough sequence.

[0026] Similarly, the original coil current sequence of the circuit breaker in a healthy state is collected, and the current sag sequence of the circuit breaker in a healthy state is obtained. The number of times in the current sag sequence of the circuit breaker in a healthy state is used as the reference operating time of the circuit breaker in a healthy baseline state.

[0027] Figure 2 The blue curve in the figure shows the curve of the coil current collected during the opening and closing of the circuit breaker as a function of time. The curve shows a trend of first rising, then plunging in the middle, and finally rising again. The green area in the figure clearly marks the current plunging sequence corresponding to the core movement stage. It intuitively shows the acquisition of the original coil current data and the automatic positioning of the current plunging sequence corresponding to the core operation stage containing the core physical characteristics (mechanical friction) in this step.

[0028] S002. Based on the fluctuation characteristics and duration of the current dip sequence, obtain the current waveform complexity factor of the core motion stage, and calculate the mode number of variational mode decomposition based on the current waveform complexity factor; perform variational mode decomposition on the current dip sequence based on the mode number of variational mode decomposition, and extract high-frequency components as mechanical friction feature components.

[0029] It should be noted that when a circuit breaker experiences a mechanical fault (such as jamming of transmission components, obstruction by foreign objects, or corrosion of components), the iron core will experience a brief pause or slowdown in its movement speed. The back electromotive force will then undergo a sudden change, which is reflected in the current waveform as irregular spikes or steps in the current trough sequence. In other words, the data in the current trough sequence fluctuates significantly. Furthermore, since the iron core experiences a brief pause or slowdown in its movement speed, it will also directly manifest as an extension of the duration of the current trough sequence. Therefore, this invention obtains the current waveform complexity factor of the iron core movement stage by analyzing the duration and fluctuation of the current trough sequence corresponding to the iron core movement stage. Its value is used to reflect whether the circuit breaker has experienced a mechanical fault.

[0030] In this embodiment of the invention, the current waveform complexity factor during the core motion phase is obtained: ; In the formula, The current waveform complexity factor represents the phase of the iron core's movement. This represents the current data value at the (i+1)th moment in the current dip sequence; This represents the current data value at the i-th moment in the current dip sequence; This represents the maximum current data value in the current dip sequence; || represents the minimum current data value in the current dip sequence; || represents the absolute value sign. Represents the number of moments in the current dip sequence; This represents the reference operating time of the circuit breaker under a healthy baseline condition. It represents the sum of the absolute values ​​of the differences between the current data at all adjacent time points in the current sag sequence. The larger the value, the more violent the fluctuation of the current sag sequence, and the circuit breaker may have a mechanical failure. Used for normalizing molecules; The larger the value, the more likely the circuit breaker is experiencing mechanical jamming, causing the core to run slower. The larger the value, the worse the mechanical condition of the circuit breaker, and the more non-stationary components are contained in the waveform.

[0031] It should be noted that when this invention uses the variational mode decomposition (VMD) algorithm to extract high-frequency components from the current signal, the number of modes is usually fixed. If a fixed number of modes is used to decompose the current signal, it may lead to under-decomposition (inability to completely extract high-frequency components) or over-decomposition (noise mixing), thereby affecting the accuracy of circuit breaker mechanical fault diagnosis. Therefore, this invention adaptively obtains the number of modes based on the current waveform complexity factor of the iron core movement stage. If the current waveform complexity factor during the core movement phase is small, it indicates that the waveform of the current trough sequence is smooth, and the circuit breaker is unlikely to have a mechanical fault. In this case, the number of modes in the variational mode decomposition is close to the number of fundamental modes, avoiding over-decomposition and the generation of spurious components. If the current waveform complexity factor during the core movement phase is large, it indicates that the waveform of the current trough sequence oscillates and the duration of the core movement phase is long, and the circuit breaker may have a mechanical fault. In this case, more modes are needed to facilitate the extraction of high-frequency components.

[0032] In this embodiment of the invention, the number of modes in the variational mode decomposition is obtained: ; In the formula, Represents the number of modes in the variational mode decomposition; This represents the number of fundamental modes in the variational mode decomposition. The sensitivity coefficient represents the adjustment value, which is preset in the embodiments of the present invention. ; The current waveform complexity factor represents the phase of the iron core's movement. Represents the logarithmic function, with restrictions The value of increases infinitely as the complexity factor of the current waveform increases. This represents the rounding function; In variational mode decomposition, the selection of the number of modes directly determines the number of signal components obtained after decomposition. It is known that the basic components of a signal are a DC component (representing the average value of the signal), a fundamental frequency (the most concentrated energy frequency component in the signal), and fundamental noise. Therefore, in this embodiment of the invention, a preset... In other embodiments, implementers may pre-set according to specific implementation conditions. The value of .

[0033] It should be noted that when a circuit breaker experiences a mechanical fault (such as jamming or friction), the iron core will generate high-frequency vibrations during its movement. These vibrations modulate the current signal, forming high-frequency components containing fault information. Therefore, this invention performs variational mode decomposition on the current dip sequence based on the mode number of variational mode decomposition, and extracts the high-frequency components as mechanical friction feature components, which facilitates subsequent analysis.

[0034] In this embodiment of the invention, the number of modes is based on variational mode decomposition. The current dip sequence is subjected to variational mode decomposition to obtain the following results: For each IMF component, calculate its center frequency and select the IMF component with the highest center frequency as the mechanical friction characteristic component.

[0035] S003. Based on the mechanical friction characteristic components, obtain the mechanical friction factor during the core motion stage; based on the mechanical friction factor during the core motion stage and the current waveform complexity factor, obtain the mechanical stall risk value.

[0036] It should be noted that the known mechanical friction characteristic component reflects the high-frequency vibration signal caused by the mechanical fault of the circuit breaker. Therefore, if the current data value in the high-frequency friction component is larger, it indicates that the circuit breaker is more likely to have a mechanical fault. Therefore, based on the current data value in the high-frequency friction component, the mechanical friction factor in the core movement stage is obtained to characterize the severity of the mechanical fault. However, since mechanical faults of circuit breakers (such as jamming and friction) often occur at the moment when the iron core is moving at high speed, and the signal energy is the richest at this time, this invention assigns a large weight to the data of the high-frequency friction component at the center position of the time axis to amplify the effective signal that reflects the true fault characteristics. At the beginning and end stages of the iron core movement, although it is still affected by electromagnetic transient noise, the mechanical movement speed is extremely low and the physical friction vibration is small. Therefore, the data of the high-frequency friction component at the edge position of the time axis is assigned a small weight. Thus, the mechanical friction factor obtained by weighting can accurately reflect the friction characteristics of the high-speed movement segment of the iron core and suppress the noise interference caused by electromagnetic transients at the beginning and end stages.

[0037] In this embodiment of the invention, the mechanical friction factor during the core movement phase is obtained: ; In the formula, The mechanical friction factor represents the stage of the iron core's movement; This represents the number of current data points in the high-frequency friction component. This represents the current data value at the i-th moment in the high-frequency friction component; This represents the current data value at the i-th moment in the current dip sequence; The number of moments in the current dip sequence is represented by , and the number of moments in the high-frequency friction component is equal to the number of moments in the current dip sequence; exp() represents an exponential function with the natural constant as the base. This represents the preset decay rate, used to control how quickly the weights decay. A larger value results in faster weight decay. In this embodiment of the invention, the preset decay rate is... In other embodiments, implementers may pre-determine specific implementation methods. The value; Representing preset hyperparameters, in this embodiment of the invention, the preset... To avoid the denominator being zero; This represents the normalization of molecules because an increase in control voltage leads to a larger overall current data, and the high-frequency friction component naturally increases proportionally. Therefore, by dividing by the corresponding current data value in the current dip sequence, the influence of voltage fluctuations is eliminated, resulting in... The value only reflects the change in mechanical friction characteristics; The smaller the value, the more likely the i-th moment in the high-frequency friction component is located at the center of the time axis and belongs to the high-speed operation stage of the iron core. The larger the value, the greater the weight assigned to the current data value at time i in the high-frequency friction component; conversely, the smaller the value, the less weight assigned to the current data value at time i. The larger the value, the more likely the i-th moment in the high-frequency friction component is located at the edge of the time axis, and it belongs to the low-speed operation stage of the iron core and is affected by electromagnetic transient noise. The smaller the value, the smaller the weight is assigned to the current data value at the i-th moment in the high-frequency friction component, thus suppressing the noise interference caused by electromagnetic transients during the start and stop phases of the iron core movement.

[0038] Figure 3 A schematic diagram representing the weighted processing of characteristic components of mechanical friction. Figure 3 The gray waveform represents the mechanical friction feature components extracted after the current dip sequence and variational mode decomposition, showing chaotic oscillations; the orange curve represents the weighted characterization curve constructed based on the core motion speed law, presenting a parabolic shape with a high middle and low ends, with a large weight for the high-speed position of the core motion (middle) and a small weight for the low-speed position of the core motion (ends); the red curve represents the final mechanical friction feature components after weighting, showing that the interference noise at both ends is significantly suppressed, and only the effective friction features of the middle section (when the core is moving at high speed) are retained.

[0039] It should be noted that mechanical failures of circuit breakers (such as jamming and friction) are essentially the result of both macroscopic motion obstruction and microscopic friction enhancement. The current waveform complexity factor during the core motion stage focuses on reflecting macroscopic sluggishness and fluctuation roughness, while the mechanical friction factor during the core motion stage focuses on reflecting microscopic high-frequency frictional vibration energy. Therefore, this invention combines the current waveform complexity factor and the mechanical friction factor during the core motion stage to obtain the mechanical stall risk value and comprehensively assess the mechanical failure risk of the circuit breaker.

[0040] In this embodiment of the invention, the mechanical stagnation risk value is obtained: ; In the formula, This represents the risk value of mechanical stagnation; The mechanical friction factor represents the stage of the iron core's movement; The current waveform complexity factor represents the phase of the iron core's movement. Represents the weight of the mechanical friction factor; Represents the weight of the current waveform complexity factor; The mechanical friction factor of a circuit breaker during the core movement phase, representing its health status; The current waveform complexity factor of a circuit breaker during the core movement phase, representing its health status. It is known that the root cause of mechanical stalling is the obstruction of the iron core's movement. The mechanical friction factor is a core indicator that directly reflects the physical resistance to the iron core's movement and is the dominant factor causing mechanical stalling. Meanwhile, the complexity of the current waveform is a detectable abnormal characteristic of the iron core's movement, used to assist in judgment. Since the two contribute differently to the risk of stalling, in this embodiment of the invention, a preset weight for the mechanical friction factor is used. Current waveform complexity factor weight In other embodiments, implementers may pre-determine specific implementation methods. as well as The value; The larger the value, the more the friction characteristics of the circuit breaker deviate from the healthy state due to mechanical failure, and the higher the risk of mechanical stagnation. The larger the value, the greater the actual current waveform complexity factor is compared to the healthy baseline value. In this case, the circuit breaker has a mechanical fault, and the risk of mechanical stall is higher. The smaller the value, the closer the actual current waveform complexity factor is to the healthy baseline value. At this time, the circuit breaker is less likely to have mechanical failures, and the lower the risk value of mechanical stall. It should be noted that the current waveform complexity factor and mechanical friction factor of the circuit breaker in a healthy state during the core movement stage are obtained as follows: based on the method for obtaining the current waveform complexity factor, the current waveform complexity factor of the current sag sequence of the circuit breaker in a healthy state is obtained, which is used as the current waveform complexity factor of the circuit breaker in a healthy state during the core movement stage; based on the method for obtaining the mechanical friction factor, the mechanical friction factor of the current sag sequence of the circuit breaker in a healthy state is obtained, which is used as the mechanical friction factor of the circuit breaker in a healthy state during the core movement stage.

[0041] S004. Determine the status of the circuit breaker based on the mechanical stagnation risk value.

[0042] In this embodiment of the invention, the preset risk value threshold T1 is 0.7. In other embodiments, the implementer can preset the value of T1 according to the specific implementation situation. If the mechanical stagnation risk value is greater than or equal to the risk value threshold, the circuit breaker has a mechanical failure, the system will alarm and notify the staff to repair it immediately.

[0043] Figure 4 This diagram illustrates how to determine the status of a circuit breaker based on the risk value of mechanical shutdown. Figure 4The red bars in the graph represent the mechanical stall risk value of the circuit breaker under test. When the mechanical stall risk value clearly exceeds the risk threshold indicated by the orange dashed line, it is determined that the circuit breaker under test has a mechanical fault and an alarm is triggered, thus achieving accurate identification and automatic alarm of mechanical faults in circuit breakers.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting the condition of an intelligent circuit breaker based on current characteristic analysis, characterized in that, include: Obtain the original coil current sequence of the circuit breaker under test; The current dip sequence corresponding to the movement stage of the iron core is located based on the original coil current sequence. Based on the fluctuation characteristics and duration of the current dip sequence, the current waveform complexity factor during the core motion phase is obtained. Based on the current waveform complexity factor, the number of modes in the variational mode decomposition is obtained; Variational mode decomposition is performed on the current dip sequence based on the mode number of variational mode decomposition, and high-frequency components are extracted as mechanical friction feature components. Based on the velocity law of the iron core, the current data values ​​at each moment in the high-frequency friction component are weighted and summed to obtain the mechanical friction factor of the iron core during the motion stage. Based on the waveform complexity factor and the mechanical friction factor, obtain the mechanical stall risk value; The health status of the circuit breaker is determined based on the mechanical stall risk value.

2. The intelligent circuit breaker state detection method based on current characteristic analysis according to claim 1, characterized in that, The process of obtaining the original coil current sequence of the circuit breaker under test includes: A Hall current sensor is connected to the control circuit of the opening / closing coil or the closing coil of the circuit breaker under test. The Hall current sensor is used to convert the current signal of the opening / closing coil or the closing coil into a voltage signal. The voltage signal is then input into a high-precision analog-to-digital converter with a sampling frequency of 1 millisecond / time to obtain the original coil current sequence of the circuit breaker under test.

3. The intelligent circuit breaker state detection method based on current characteristic analysis according to claim 1, characterized in that, The current dip sequence corresponding to the movement stage of the iron core based on the original coil current sequence includes: Obtain the first-order difference value at each time step in the original coil current sequence. If the first-order difference value at time step t1 in the original coil current sequence is less than 0 and the first-order difference value at time step t1-1 is greater than 0, then record time step t1 as the starting point and the first starting point in the original coil current sequence as the target starting point. The current sequence after the target starting point is taken as the target current sequence. If the first-order difference value at time step t2 in the target current sequence is greater than 0 and the first-order difference value at time step t2-1 is less than 0, then record time step t2 as the ending point. The first ending point in the target current sequence is the target ending point. The sequence segment formed between the target starting point and the target ending point is recorded as the current trough sequence.

4. The intelligent circuit breaker state detection method based on current characteristic analysis according to claim 1, characterized in that, The current waveform complexity factor is obtained by: The original coil current sequence of the circuit breaker in a healthy state is collected, and the current sag sequence of the circuit breaker in a healthy state is obtained. The number of times in the current sag sequence of the circuit breaker in a healthy state is used as the reference operating time of the circuit breaker in a healthy reference state, denoted as . ; , The current waveform complexity factor represents the phase of the iron core's movement. This represents the current data value at the (i+1)th moment in the current dip sequence; This represents the current data value at the i-th moment in the current dip sequence; This represents the maximum current data value in the current dip sequence; Represents the minimum current data value in the current dip sequence; || is the absolute value symbol. This represents the number of moments in the current dip sequence.

5. The intelligent circuit breaker state detection method based on current characteristic analysis according to claim 1, characterized in that, The process of obtaining the number of modes in the variational mode decomposition includes: ； In the formula, Represents the number of modes in the variational mode decomposition; This represents the number of fundamental modes in the variational mode decomposition. Represents the adjustment sensitivity coefficient; The current waveform complexity factor represents the phase of the iron core's movement. Represents the logarithmic function, with restrictions The value of increases infinitely as the complexity factor of the current waveform increases. This represents the rounding function.

6. The intelligent circuit breaker state detection method based on current characteristic analysis according to claim 1, characterized in that, The variational mode decomposition based on the mode number of the current dip sequence is performed to extract high-frequency components as mechanical friction feature components, including: Mode number based on variational mode decomposition The current dip sequence is subjected to variational mode decomposition to obtain the following results: For each IMF component, calculate its center frequency and select the IMF component with the highest center frequency as the mechanical friction characteristic component.

7. The intelligent circuit breaker state detection method based on current characteristic analysis according to claim 1, characterized in that, The method of obtaining the mechanical friction factor during the core movement phase includes: ； In the formula, The mechanical friction factor represents the stage of the iron core's movement; This represents the number of current data points in the high-frequency friction component. This represents the current data value at the i-th moment in the high-frequency friction component; This represents the current data value at the i-th moment in the current dip sequence; The number of time points in the current dip sequence is represented by exp(); exp() represents an exponential function with the natural constant as the base. Represents the preset decay rate; This represents the preset hyperparameters.

8. The intelligent circuit breaker state detection method based on current characteristic analysis according to claim 1, characterized in that, The acquisition of the mechanical stall risk value includes: Obtain the current waveform complexity factor and mechanical friction factor of the circuit breaker in the core movement phase to obtain its health status. , This represents the risk value of mechanical stagnation; The mechanical friction factor represents the stage of the iron core's movement; The current waveform complexity factor represents the phase of the iron core's movement. Represents the weight of the mechanical friction factor; Represents the weight of the current waveform complexity factor; The mechanical friction factor of a circuit breaker during the core movement phase, representing its health status; The current waveform complexity factor of a circuit breaker during the core movement phase, representing its health status.

9. The intelligent circuit breaker state detection method based on current characteristic analysis according to claim 1, characterized in that, The determination of the circuit breaker's health status based on the mechanical stall risk value includes: A preset risk threshold T1 is set. If the mechanical stall risk value is greater than or equal to the risk threshold, the circuit breaker has a mechanical fault. The system will issue an alarm and notify the staff to carry out immediate repairs.

10. The intelligent circuit breaker state detection method based on current characteristic analysis according to claim 8, characterized in that, The current waveform complexity factor and mechanical friction factor of the circuit breaker during the core movement phase for obtaining its health status include: Based on the method of obtaining the current waveform complexity factor, the current waveform complexity factor of the current sag sequence of the circuit breaker in a healthy state is obtained, which is used as the current waveform complexity factor of the circuit breaker in a healthy state during the core movement stage; based on the method of obtaining the mechanical friction factor, the mechanical friction factor of the current sag sequence of the circuit breaker in a healthy state is obtained, which is used as the mechanical friction factor of the circuit breaker in a healthy state during the core movement stage.

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