A method for identifying the switch safety of circuit breaker equipment

Abstract

This invention provides a method for identifying the switching safety of circuit breaker equipment, belonging to the technical field of circuit breaker equipment switching safety identification. The method includes: collecting electrical quantity data (voltage, current) and mechanical quantity data (displacement, velocity, acceleration, vibration, etc.) during the switching process; establishing a set of mathematical equations for the electrical and mechanical quantities, and determining the value range of each parameter through numerical and analytical solutions; normalizing the collected data and extracting a feature matrix; inputting the feature matrix into a pre-trained fault mode recognition model to identify the fault modes of circuit breaker switching; and outputting the diagnostic results to maintenance personnel, providing a basis for equipment status monitoring and fault early warning. This invention addresses the technical problem that existing technologies, relying on a single type of data, cannot accurately reflect the true state of circuit breakers due to the complex and variable operating environment and numerous external interference factors.

Description

Technical Field

[0001] This invention belongs to the field of switch safety identification technology for circuit breaker equipment, and more specifically, relates to a method for switch safety identification of circuit breaker equipment. Background Technology

[0002] With the rapid development of power systems and the widespread application of smart grids, circuit breakers, as key equipment in medium-voltage distribution networks, directly affect the safe and stable operation of the power system due to their operational reliability. In practical applications, circuit breakers frequently perform opening and closing operations, making them prone to various fault modes, such as mechanical jamming, contact erosion, and spring failure. These faults not only cause circuit breakers to malfunction but may also trigger more serious accidents, resulting in large-scale power outages and equipment damage. Therefore, timely and accurate identification of circuit breaker fault modes is of great significance.

[0003] Currently, circuit breaker fault diagnosis mainly relies on regular maintenance and on-site manual inspections. This method is not only time-consuming and labor-intensive, but also makes it difficult to detect potential faults in a timely manner. In recent years, with the advancement of sensing and signal processing technologies, fault diagnosis methods based on vibration signals, acoustic emission signals, and current signals have gradually emerged. However, these methods often focus only on a single type of signal, making it difficult to comprehensively reflect the operating status of the circuit breaker. Furthermore, most existing fault diagnosis algorithms are based on traditional signal processing techniques and simple classification models, which often result in unsatisfactory diagnostic accuracy and reliability when faced with complex fault modes.

[0004] In practical applications, circuit breakers operate in complex and variable environments with numerous external interference factors, making it difficult for a single type of data to accurately reflect the true state of the circuit breaker. Furthermore, circuit breaker fault modes are diverse and complex, often manifesting as abnormal combinations of multiple parameters. Existing technologies struggle to effectively handle these complex fault characteristics, leading to high rates of misdiagnosis and missed diagnosis. Summary of the Invention

[0005] In view of this, the present invention provides a method for identifying the switching safety of circuit breaker equipment, which can solve the technical problem that the circuit breaker's operating environment is complex and changeable, with many external interference factors, and that existing technologies rely on a single type of data to accurately reflect the true state of the circuit breaker.

[0006] This invention is implemented as follows:

[0007] A first aspect of the present invention provides a method for identifying the switch safety of a circuit breaker device, comprising the following steps:

[0008] S10. Collect electrical and mechanical quantity data during the opening and closing process of the circuit breaker switch. The electrical quantity data includes the three-phase voltage and current waveforms of the circuit breaker, the operating current and voltage waveforms of the switching mechanism, and the current and voltage parameters of the contacts during the opening and closing process. The mechanical quantity data includes the displacement, velocity, and acceleration curves of the switching mechanism, as well as the vibration signals of the springs and dampers of the circuit breaker.

[0009] S20. Establish a set of electrical quantity equations, including three-phase voltage equations, three-phase current equations, switching mechanism operating current equations, switching mechanism operating voltage equations, and contact opening and closing process current and voltage equations.

[0010] S30. Establish a set of mechanical quantity equations, including the displacement equation of the switching mechanism, the velocity equation of the switching mechanism, the acceleration equation of the switching mechanism, the vibration equation of the circuit breaker spring, and the vibration equation of the circuit breaker damper.

[0011] S40. Solve the set of electrical quantity equations to obtain multiple numerical solutions for electrical quantities, namely, the peak value of three-phase voltage, the peak value of three-phase current, the maximum value of the operating current of the switching mechanism, the maximum value of the operating voltage of the switching mechanism, the maximum value of the current during the contact opening and closing process, and the maximum value of the voltage during the contact opening and closing process.

[0012] S50. Solve the set of mechanical quantity equations to obtain multiple numerical solutions for mechanical quantities, namely, the maximum displacement of the switching mechanism, the maximum velocity of the switching mechanism, the maximum acceleration of the switching mechanism, the vibration frequency of the circuit breaker spring, and the vibration amplitude of the circuit breaker damper.

[0013] S60. Solve the electrical quantity equations analytically to obtain multiple analytical solutions for electrical quantities. Substitute these solutions into the preset initial conditions for electrical quantities to obtain multiple ranges of electrical quantities.

[0014] S70. Solve the mechanical quantity equations analytically to obtain multiple analytical solutions for mechanical quantities. Substitute these solutions into the preset initial conditions for mechanical quantities to obtain multiple ranges of mechanical quantities.

[0015] S80. Normalize the numerical solutions of the multiple electrical quantities, the numerical solutions of the multiple mechanical quantities, the maximum and minimum values ​​of the ranges of the multiple electrical quantities, and the maximum and minimum values ​​of the ranges of the multiple mechanical quantities so that all parameter values ​​fall within the [0,1] interval. Then, concatenate the normalized data and extract features through principal component analysis or other dimensionality reduction methods to obtain a feature matrix.

[0016] S90. Input the feature matrix into the pre-trained circuit breaker switch opening and closing fault mode recognition model to obtain the circuit breaker switch opening and closing fault mode vector. Compare the highest fault probability in the fault mode vector with a preset safety threshold. If the highest fault probability is greater than the safety threshold, the circuit breaker is determined to have low switch safety; otherwise, the circuit breaker is determined to have high switch safety. The preset safety threshold is 0.8.

[0017] The analytical solutions for the multiple electrical quantities are: analytical expression for three-phase voltage, analytical expression for three-phase current, analytical expression for operating current of switching mechanism, analytical expression for operating voltage of switching mechanism, analytical expression for current during contact opening and closing process, and analytical expression for voltage during contact opening and closing process.

[0018] Furthermore, the ranges of the plurality of electrical quantities are: the peak range of three-phase voltage; the peak range of three-phase current; the maximum range of operating current of the switching mechanism; the maximum range of operating voltage of the switching mechanism; the maximum range of current during contact opening and closing; and the maximum range of voltage during contact opening and closing.

[0019] Furthermore, the analytical solutions for the plurality of electrical quantities are: analytical expression for three-phase voltage; analytical expression for three-phase current; analytical expression for operating current of switching mechanism; analytical expression for operating voltage of switching mechanism; analytical expression for current during contact opening and closing process; and analytical expression for voltage during contact opening and closing process.

[0020] Furthermore, the ranges of the multiple mechanical quantities are: the maximum displacement range of the switching mechanism; the maximum speed range of the switching mechanism; the maximum acceleration range of the switching mechanism; the vibration frequency range of the circuit breaker spring; and the vibration amplitude range of the circuit breaker damper.

[0021] The three-phase voltage equation is specifically expressed as follows:

[0022]

[0023] In the formula, U φ (t) is a function of the voltage of a certain phase as a function of time; U m The fundamental amplitude is measured using a voltage transformer; ω is the angular frequency, equal to 2πf, where f is the system frequency; t is the time variable; θ φ The initial phase angle is determined by a synchronous measuring device; U n The amplitude of the nth harmonic is obtained through Fourier analysis; φ n U is the initial phase angle of the nth harmonic; N is the highest harmonic order considered; U dc The DC bias component is detected by a voltage measuring device; τ is a time constant related to the system impedance; ε(t) is a random noise term.

[0024] The three-phase current equation is specifically expressed as follows:

[0025]

[0026] In the formula, I φ (t) is a function of the current in a certain phase as a function of time; I m The fundamental amplitude is measured using a current transformer; φ is the power factor angle, measured using a power analyzer; I n The amplitude of the nth harmonic is obtained through Fourier analysis; φ n I represents the phase difference of the nth harmonic; dc The DC bias component is detected by a current measuring device; τ I K is the current time constant, which is related to the system impedance and inductance; t η is the eddy current coefficient, which is related to the circuit breaker core material; η(t) is the random noise term.

[0027] The operating current equation of the switching mechanism is specifically expressed as follows:

[0028]

[0029] In the formula, I op (t) represents the operating current of the switching mechanism; I0 is the initial current, determined by the initial state of the operating mechanism; K m The mass coefficient is related to the mass of the moving parts of the operating mechanism; x(t) is the displacement function of the operating mechanism; K v K is the velocity damping coefficient, which is related to the friction of the operating mechanism. s The spring stiffness coefficient is determined by the spring characteristics of the operating mechanism; I f The current is the Coulomb triboelectric current, which is related to the material of the contact surface; sign() is the sign function; I e τ is the amplitude of the eddy current. e ξ is the eddy current time constant; ξ(t) is the random noise term;

[0030] The operating voltage equation of the switching mechanism is specifically expressed as follows:

[0031]

[0032] In the formula, U op (t) represents the operating voltage of the switching mechanism; U0 represents the rated operating voltage; R c L is the equivalent resistance of the operating circuit. c K is the equivalent inductance of the operating circuit. b ω is the back electromotive force coefficient; μ(t) is the voltage fluctuation function, simulating grid fluctuations; v ζ(t) represents the voltage fluctuation angular frequency; ζ(t) represents the random noise term.

[0033] The current and voltage equations for the contact opening and closing process are specifically expressed as follows:

[0034]

[0035] In the formula, I c (t), U c (t) represents the contact current and voltage; I a U a τ represents the initial current and voltage amplitudes. a τ c ω represents the time constants for current and voltage decay; a I is the angular frequency of the current oscillation; b U b For steady-state current and voltage components; τ b τ d I represents the rise time constants of current and voltage; arc U arc Characteristic values ​​of arc current and voltage; K arc l is the arc formation rate coefficient; arc γ(t) is the arc length function; I0 is a small current constant to prevent division by zero errors; γ(t) and δ(t) are random noise terms.

[0036] The displacement equation of the switching mechanism is specifically expressed as follows:

[0037]

[0038] In the formula, x(t) is the displacement of the switching mechanism; ζ is the damping ratio; ω n F is the natural angular frequency. m (t) is the driving force function; m is the mass of the switching mechanism; F f For friction; k is the spring stiffness; A e ω represents the amplitude of the external vibration. e ω is the external vibration angular frequency; ∈(t) represents the random disturbance;

[0039] The speed equation of the switching mechanism is specifically expressed as follows:

[0040]

[0041] In the formula, v(t) is the speed of the switching mechanism; v0 is the initial speed; β is the damping coefficient, which is equal to ζω. n φ is the phase angle, equal to arctan(ω). e / β); ν(t) represents the random velocity perturbation;

[0042] The acceleration equation of the switching mechanism is specifically expressed as follows:

[0043]

[0044] In the formula, a(t) is the acceleration of the switching mechanism; κ(t) is the random disturbance of acceleration.

[0045] The circuit breaker spring vibration equation is specifically expressed as follows:

[0046]

[0047] In the formula, y(t) is the spring displacement; ζ s ω is the spring damping ratio; s F is the natural angular frequency of the spring. s (t) represents the external force acting on the spring; m s A is the equivalent mass of the spring; s α is the initial amplitude of the spring's vibration. s λ is the spring vibration attenuation coefficient; λ(t) is the random disturbance of the spring vibration.

[0048] The vibration equation of the circuit breaker damper is specifically expressed as follows:

[0049]

[0050] In the formula, z(t) is the damper displacement; ζ d ω is the damping ratio of the damper. d F is the natural angular frequency of the damper. d (t) represents the external force acting on the damper; m d For the damper mass; c d A is the nonlinear damping coefficient; d α is the initial vibration amplitude of the damper; d ρ(t) is the damper vibration attenuation coefficient; ρ(t) is the random disturbance of the damper vibration.

[0051] Furthermore, the training steps for the circuit breaker switch opening and closing fault mode recognition model specifically include:

[0052] Establish a training dataset, specifically by acquiring electrical and mechanical quantity data during the opening and closing process of circuit breaker switches with multiple known faults, and generating a feature matrix according to steps S10 to S80. The input to the training is the generated feature matrix, and the output of the training is the known fault.

[0053] Network training: A multilayer perceptron network is trained using the training dataset to obtain the circuit breaker switch opening and closing fault mode recognition model.

[0054] Compared with existing technologies, the circuit breaker safety identification method provided by this invention establishes a comprehensive mathematical model that reflects the operating status of the circuit breaker by comprehensively collecting and analyzing electrical and mechanical data. This method not only considers traditional electrical parameters such as voltage and current, but also incorporates mechanical parameters such as the displacement, velocity, and acceleration of the switching mechanism, as well as the vibration signals of springs and dampers, thereby achieving comprehensive monitoring of the circuit breaker's status.

[0055] By establishing sets of electrical and mechanical equations, this method can accurately describe the dynamic characteristics of circuit breakers during opening and closing. Numerical and analytical solutions to these equations not only yield the specific values ​​of key parameters but also their theoretical ranges. This dual-solution method significantly improves the accuracy and reliability of fault diagnosis.

[0056] This invention employs advanced data processing and feature extraction techniques. Through normalization and principal component analysis, complex multidimensional data is transformed into a low-dimensional feature matrix, effectively extracting key fault features, reducing data redundancy, and improving the efficiency of subsequent fault identification.

[0057] In the fault identification phase, this method uses a multilayer perceptron neural network model, which has powerful nonlinear mapping capabilities and self-learning abilities, effectively handling complex fault modes. By outputting fault mode vectors and their probabilities, it provides maintenance personnel with intuitive and reliable decision-making support.

[0058] Compared with the prior art, the method of the present invention has the following significant advantages:

[0059] 1. It enables comprehensive monitoring of the circuit breaker status, improving the comprehensiveness and accuracy of fault diagnosis.

[0060] 2. By establishing a precise mathematical model, the ability to extract fault features and the accuracy of fault mode identification have been improved.

[0061] 3. Advanced data processing and machine learning technologies have been adopted to improve the intelligence and adaptability of fault diagnosis.

[0062] 4. It can identify complex failure modes and provide probability assessments, providing strong support for predictive maintenance.

[0063] In summary, this invention solves the technical problem that the operating environment of circuit breakers is complex and variable, with numerous external interference factors, and that existing technologies rely on a single type of data to accurately reflect the true state of circuit breakers. Attached Figure Description

[0064] Figure 1 A flowchart of the method provided by the present invention. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0066] like Figure 1 The diagram shown is a flowchart of a switch safety identification method for circuit breaker equipment provided by the present invention. This method includes the following steps: (The steps are not explicitly stated in the original text.)

[0067] S10. Collect electrical and mechanical data during the opening and closing process of the circuit breaker switch. The electrical data includes the three-phase voltage and current waveforms of the circuit breaker, the operating current and voltage waveforms of the switching mechanism, and the current and voltage parameters of the contacts during the opening and closing process. The mechanical data includes the displacement, velocity, and acceleration curves of the switching mechanism, as well as the vibration signals of the circuit breaker's springs and dampers.

[0068] S20. Establish a set of electrical quantity equations, including three-phase voltage equations, three-phase current equations, switching mechanism operating current equations, switching mechanism operating voltage equations, and contact opening and closing process current and voltage equations.

[0069] S30. Establish a set of mechanical quantity equations, including the displacement equation of the switching mechanism, the velocity equation of the switching mechanism, the acceleration equation of the switching mechanism, the vibration equation of the circuit breaker spring, and the vibration equation of the circuit breaker damper.

[0070] S40. Solve the electrical quantity equations to obtain multiple numerical solutions for electrical quantities, namely, the peak value of three-phase voltage, the peak value of three-phase current, the maximum value of the operating current of the switching mechanism, the maximum value of the operating voltage of the switching mechanism, the maximum value of the current during the contact opening and closing process, and the maximum value of the voltage during the contact opening and closing process.

[0071] S50. Solve the mechanical quantity equations to obtain multiple numerical solutions for mechanical quantities, namely the maximum displacement of the switching mechanism, the maximum velocity of the switching mechanism, the maximum acceleration of the switching mechanism, the vibration frequency of the circuit breaker spring, and the vibration amplitude of the circuit breaker damper.

[0072] S60. Solve the electrical quantity equations analytically to obtain multiple analytical solutions for electrical quantities. Substitute these solutions into the preset initial conditions for electrical quantities to obtain multiple ranges of electrical quantities.

[0073] S70. Solve the mechanical quantity equations analytically to obtain multiple analytical solutions for mechanical quantities. Substitute these solutions into the preset initial conditions for mechanical quantities to obtain multiple ranges of mechanical quantities.

[0074] S80. Normalize the numerical solutions of multiple electrical quantities, multiple numerical solutions of multiple mechanical quantities, the maximum and minimum values ​​of multiple electrical quantity ranges, and the maximum and minimum values ​​of multiple mechanical quantity ranges so that all parameter values ​​fall within the [0,1] interval. Then, concatenate the normalized data and extract features through principal component analysis or other dimensionality reduction methods to obtain the feature matrix.

[0075] S90. Input the feature matrix into the pre-trained circuit breaker switch opening and closing fault mode recognition model to obtain the circuit breaker switch opening and closing fault mode vector. Based on the highest fault probability in the fault mode vector, compare it with a pre-set safety threshold. If the highest fault probability is greater than the safety threshold, the circuit breaker is determined to have low switch safety; otherwise, the circuit breaker is determined to have high switch safety. The safety threshold is preset to 0.8.

[0076] The specific implementation methods of the above steps are described in detail below:

[0077] The specific implementation of step S10 is as follows: First, high-precision voltage transformers and current transformers are installed to collect three-phase voltage and current waveform data of the circuit breaker. Second, Hall effect current sensors and voltage sensors are installed on the switching mechanism to collect the operating current and voltage waveforms of the switching mechanism. Third, miniature current and voltage sensors are installed at the contacts to collect the current and voltage parameters during the opening and closing process of the contacts. Then, displacement sensors, velocity sensors, and acceleration sensors are installed on the switching mechanism to collect the displacement, velocity, and acceleration curves of the switching mechanism. Finally, vibration sensors are installed on the springs and dampers of the circuit breaker to collect vibration signals. The sampling frequency is set to 10kHz, and the sampling duration is 1 second. A low-pass filter is used to eliminate high-frequency noise during data acquisition, and the cutoff frequency is set to 5kHz. The acquired data is converted from analog to digital and stored in a high-speed cache for subsequent processing. The purpose of this step is to obtain comprehensive data during the operation of the circuit breaker, providing a basis for subsequent analysis.

[0078] The specific implementation of step S20 is as follows: Based on the data collected in step S10, a set of electrical quantity equations is established. First, the three-phase voltage and current waveforms are analyzed using Fourier transform to extract the fundamental and harmonic components, and three-phase voltage and current equations are established. Considering the influence of the 5th, 7th, and 11th harmonics, the harmonic order N is set to 11. Then, based on the operating characteristics of the switching mechanism, the operating current and voltage equations of the switching mechanism are established, considering the influence of inductance, resistance, and back electromotive force. Finally, based on the physical model of the contact opening and closing process, the current and voltage equations for the contact opening and closing process are established, considering arc characteristics and contact material characteristics. The parameters in the equation set are obtained by fitting measured data using the least squares method. The purpose of this step is to establish a mathematical model that accurately reflects the electrical characteristics of the circuit breaker, laying the foundation for subsequent analysis.

[0079] The specific implementation of step S30 is as follows: Based on the data collected in step S10, a set of mechanical quantity equations is established. First, the displacement, velocity, and acceleration data of the switching mechanism are fitted using the least squares method to establish the displacement, velocity, and acceleration equations of the switching mechanism. The effects of friction, spring force, and driving force are considered. Then, time-frequency analysis is performed on the vibration signal of the circuit breaker spring to extract the main vibration modes and establish the vibration equation of the circuit breaker spring. Finally, nonlinear system identification is performed on the vibration signal of the circuit breaker damper to establish the vibration equation of the circuit breaker damper, considering nonlinear damping characteristics. The parameters in the equation set are obtained through optimization using a genetic algorithm to minimize the error between the model prediction and the measured values. The purpose of this step is to establish a mathematical model that accurately reflects the mechanical characteristics of the circuit breaker, providing a basis for subsequent analysis.

[0080] The specific implementation of step S40 is as follows: The electrical quantity equations established in step S20 are numerically solved. First, for the three-phase voltage and three-phase current equations, the peak values ​​are directly calculated by substituting the time variable. Then, for the switching mechanism operating current and operating voltage equations, the fourth-order Runge-Kutta method is used for numerical integration, with a time step of 0.1 ms. Finally, for the contact opening and closing process current and voltage equations, since the equations are rigid, the backward difference method is used for solving, with the time step adaptively adjusted, ranging from 0.01 ms to 0.1 ms. During the solution process, the Newton-Raphson method is used to handle nonlinear terms. Through numerical solution, the peak values ​​of the three-phase voltage and three-phase current, the maximum value of the switching mechanism operating current, the maximum value of the switching mechanism operating voltage, the maximum value of the contact opening and closing process current, and the maximum value of the contact opening and closing process voltage are obtained. The purpose of this step is to obtain the specific values ​​of key electrical parameters during circuit breaker operation, providing a quantitative basis for fault diagnosis.

[0081] The specific implementation of step S50 is as follows: The mechanical quantity equations established in step S30 are numerically solved. First, for the displacement, velocity, and acceleration equations of the switching mechanism, a fifth-order Runge-Kutta method with variable step size is used for numerical integration, with an initial step size of 0.1 ms and an error tolerance of 1e-6. Then, for the circuit breaker spring vibration equation, the Newmark-β method is used for solution, with β set to 0.25, γ set to 0.5, and a time step of 0.1 ms. Finally, for the circuit breaker damper vibration equation, due to the presence of strong nonlinearity, a prediction-correction method is used for solution. The prediction step uses the fourth-order Adams-Bashforth formula, and the correction step uses the fourth-order Adams-Moulton formula, with a time step of 0.1 ms. Through numerical solution, the maximum displacement, maximum velocity, maximum acceleration of the switching mechanism, the vibration frequency of the circuit breaker spring, and the vibration amplitude of the circuit breaker damper are obtained. The purpose of this step is to obtain the specific values ​​of key mechanical parameters during circuit breaker operation, providing a quantitative basis for fault diagnosis.

[0082] The specific implementation of step S60 is as follows: The electrical quantity equations established in step S20 are solved analytically. First, the analytical solutions for the three-phase voltage and three-phase current equations are directly written. Then, the Laplace transform method is used to solve the operating current and voltage equations of the switching mechanism, considering the influence of initial conditions. Finally, the perturbation method is used to perform an approximate analytical solution for the contact opening and closing process, expanding to second-order terms. The parameters in the analytical solution are obtained by fitting measured data using the least squares method. Then, the preset initial electrical quantity conditions are substituted into the analytical solution to obtain multiple electrical quantity ranges. The initial conditions are set based on statistical analysis of a large amount of historical data, such as the range of the initial phase angle of the three-phase voltage being [-π / 6, π / 6], and the range of the initial current of the switching mechanism being [0.8In, 1.2In], where In is the rated current. The purpose of this step is to obtain the theoretical variation range of the circuit breaker's electrical parameters, providing a benchmark for identifying abnormal states.

[0083] The specific implementation of step S70 is as follows: The mechanical quantity equations established in step S30 are solved analytically. First, for the displacement, velocity, and acceleration equations of the switching mechanism, the homogeneous equations are solved using the characteristic root method, and then the non-homogeneous equations are solved using the constant variation method. Next, for the circuit breaker spring vibration equation, the separation of variables method is used, considering the influence of boundary conditions. Finally, for the circuit breaker damper vibration equation, the harmonic equilibrium method is used for approximate analytical solution, retaining only the third harmonic term. The parameters in the analytical solution are obtained by fitting measured data using a particle swarm optimization algorithm. Then, the preset initial mechanical quantity conditions are substituted into the analytical solution to obtain multiple mechanical quantity ranges. The initial conditions are set based on equipment specifications and historical operating data, such as the initial displacement range of the switching mechanism being [-1mm, 1mm], and the initial compression range of the spring being [0.9L0, 1.1L0], where L0 is the free length of the spring. The purpose of this step is to obtain the theoretical variation range of the circuit breaker's mechanical parameters, providing a benchmark for identifying abnormal states.

[0084] The specific implementation of step S80 is as follows: First, the multiple electrical quantity numerical solutions and multiple mechanical quantity numerical solutions obtained in steps S40 and S50 are subjected to maximum-minimum normalization processing, mapping each parameter value to the interval [0,1]. Then, the maximum and minimum values ​​of the multiple electrical quantity ranges and multiple mechanical quantity ranges obtained in steps S60 and S70 are taken and subjected to maximum-minimum normalization processing respectively. Next, the normalized data are combined into a feature vector according to a predetermined order. In order to reduce the dimensionality of the feature vector and extract the main features, the principal component analysis (PCA) method is used for feature extraction. In the PCA process, the covariance matrix of the feature vector is first calculated, and then the eigenvalues ​​and eigenvectors of the covariance matrix are solved. The top k principal components with a cumulative contribution rate of 95% are selected, and the original feature vector is projected onto these k principal components to obtain the dimensionality-reduced feature matrix. If the PCA effect is not ideal, the kernel principal component analysis (KPCA) method is used, and a Gaussian kernel function is used for nonlinear feature extraction. The purpose of this step is to transform complex multidimensional data into a low-dimensional feature matrix that is easy to analyze, thereby improving the efficiency and accuracy of subsequent fault identification.

[0085] The specific implementation of step S90 is as follows: First, a multilayer perceptron neural network is constructed as a fault mode recognition model for the circuit breaker switch opening and closing. This neural network includes one input layer, two hidden layers, and one output layer. The number of neurons in the input layer is the same as the number of columns in the feature matrix. The number of neurons in the first hidden layer is 1.5 times that of the input layer, the number of neurons in the second hidden layer is 0.75 times that of the input layer, and the number of neurons in the output layer is the same as the number of predefined fault modes. The hidden layers use the ReLU activation function, and the output layer uses the Softmax activation function. Then, the feature matrix obtained in step S80 is input into the neural network. After forward propagation calculation, the result of the output layer is obtained, which is the fault mode vector. Each element represents the probability of the corresponding fault mode. Finally, the fault mode vector is output to the maintenance personnel, along with the three fault modes with the highest probabilities and their corresponding probability values. If the highest probability value is lower than a preset threshold (e.g., 0.7), it indicates that there may be an unknown fault mode, and further investigation is recommended. The purpose of this step is to quickly identify the fault modes of the circuit breaker based on the extracted features, providing a basis for decision-making for maintenance personnel.

[0086] The following is a detailed description of each equation:

[0087] 1. Three-phase voltage equations:

[0088]

[0089] In the formula, U φ (t) is a function of the voltage of a certain phase as a function of time; U m ω is the fundamental frequency amplitude, obtained by measuring through a voltage transformer; ω is the angular frequency, equal to 2πf, where f is the system frequency (usually 50Hz or 60Hz); t is the time variable; θ φ The initial phase angle is determined by a synchronous measuring device; U n The amplitude of the nth harmonic is obtained through Fourier analysis; θ n U is the initial phase angle of the nth harmonic; N is the highest harmonic order considered; U dc The DC bias component is detected by a voltage measuring device; τ is a time constant related to the system impedance; ε(t) is a random noise term that follows a normal distribution N(0,σ). 2 ).

[0090] 2. Three-phase current equations:

[0091]

[0092] In the formula, I φ (t) is a function of the current in a certain phase as a function of time; I m The fundamental amplitude is measured using a current transformer; φ is the power factor angle, measured using a power analyzer; In The amplitude of the nth harmonic is obtained through Fourier analysis; φ n I represents the phase difference of the nth harmonic; dc The DC bias component is detected by a current measuring device; τ I K is the current time constant, which is related to the system impedance and inductance; t The eddy current coefficient is related to the circuit breaker core material; η(t) is the random noise term, which follows a normal distribution.

[0093] 3. Equation for the operating current of the switching mechanism:

[0094]

[0095] In the formula, I op (t) represents the operating current of the switching mechanism; I0 is the initial current, determined by the initial state of the operating mechanism; K m The mass coefficient is related to the mass of the moving parts of the operating mechanism; x(t) is the displacement function of the operating mechanism; K v K is the velocity damping coefficient, which is related to the friction of the operating mechanism. s The spring stiffness coefficient is determined by the spring characteristics of the operating mechanism; I f The current is the Coulomb triboelectric current, which is related to the material of the contact surface; sign() is the sign function; I e τ is the amplitude of the eddy current. e ξ is the eddy current time constant; ξ(t) is the random noise term, which follows a normal distribution.

[0096] 4. Switching mechanism operating voltage equation:

[0097]

[0098] In the formula, U op (t) represents the operating voltage of the switching mechanism; U0 represents the rated operating voltage; R c L is the equivalent resistance of the operating circuit. c K is the equivalent inductance of the operating circuit. b ω is the back electromotive force coefficient; μ(t) is the voltage fluctuation function, simulating grid fluctuations; v ζ(t) is the voltage fluctuation angular frequency; ζ(t) is the random noise term, which follows a normal distribution.

[0099] 5. Current and voltage equations during the contact opening and closing process:

[0100]

[0101] In the formula, I c (t), U c(t) represents the contact current and voltage; I a U a τ represents the initial current and voltage amplitudes. a τ c ω represents the time constants for current and voltage decay; a I is the angular frequency of the current oscillation; b U b For steady-state current and voltage components; τ b τ d I represents the rise time constants of current and voltage; arc U arc Characteristic values ​​of arc current and voltage; K arc l is the arc formation rate coefficient; arc γ(t) is the arc length function; I0 is a small current constant to prevent division by zero errors; γ(t) and δ(t) are random noise terms that follow a normal distribution.

[0102] 6. Displacement equation of the switching mechanism:

[0103]

[0104] In the formula, x(t) is the displacement of the switching mechanism; ζ is the damping ratio; ω n F is the natural angular frequency. m (t) is the driving force function; m is the mass of the switching mechanism; F f For friction; k is the spring stiffness; A e ω represents the amplitude of the external vibration. e Let be the external vibration angular frequency; ∈(t) represents a random disturbance that follows a normal distribution.

[0105] 7. Speed ​​equation of the switching mechanism:

[0106]

[0107] In the formula, v(t) is the speed of the switching mechanism; v0 is the initial speed; β is the damping coefficient, which is equal to ζω. n φ is the phase angle, equal to arctan(ω). e / β); ν(t) represents the random velocity perturbation, which follows a normal distribution.

[0108] 8. Acceleration equation of the switching mechanism:

[0109]

[0110] In the formula, a(t) is the acceleration of the switching mechanism; k(t) is the random perturbation of acceleration, which follows a normal distribution.

[0111] 9. Circuit breaker spring vibration equation:

[0112]

[0113] In the formula, y(t) is the spring displacement; ζ s ω is the spring damping ratio; s F is the natural angular frequency of the spring. s (t) represents the external force acting on the spring; m s A is the equivalent mass of the spring; s α is the initial amplitude of the spring's vibration. s λ is the spring vibration damping coefficient; λ(t) is the random disturbance of the spring vibration, which follows a normal distribution.

[0114] 10. Vibration equation of circuit breaker damper:

[0115]

[0116] In the formula, z(t) is the damper displacement; ζ d ω is the damping ratio of the damper. d F is the natural angular frequency of the damper. d (t) represents the external force acting on the damper; m d For the damper mass; c d A is the nonlinear damping coefficient; d α is the initial vibration amplitude of the damper; d ρ(t) is the damper vibration attenuation coefficient; ρ(t) is the random vibration disturbance of the damper, which follows a normal distribution.

[0117] These equations take into account a variety of complex factors, including nonlinear effects, random disturbances, and system coupling. Each parameter has a physical meaning and can be obtained through measurement, calculation, or estimation. These equations can more comprehensively describe the electrical and mechanical behavior of circuit breaker switches during opening and closing.

[0118] The numerical solution process for each equation is described in detail below. The classic fourth-order method (RK4) of the Runge-Kutta method will be used to solve these differential equations. The solution process for each equation is as follows:

[0119] 1. Three-phase voltage equations:

[0120] This is an explicit function and does not require numerical solution. The voltage value can be calculated directly at a given time point.

[0121] 2. Three-phase current equations:

[0122] It is also an explicit function and can be calculated directly.

[0123] 3. Equation for the operating current of the switching mechanism:

[0124] This equation depends on the displacement function x(t), so the displacement equation needs to be solved first.

[0125] 4. Switching mechanism operating voltage equation:

[0126] This equation also depends on the displacement function x(t) and the operating current I. o p(t) requires solving these two functions first.

[0127] 5. Current and voltage equations during the contact opening and closing process:

[0128] These two equations are coupled and need to be solved simultaneously. They can be viewed as a two-dimensional system:

[0129] Let y1 = I c y2=U c Then we have:

[0130]

[0131] Solve using the RK4 method:

[0132] Given the initial condition y1(0)=I c (0),y2(0)=U c (0), time step h, for each time step:

[0133]

[0134] 6. Displacement equation of the switching mechanism:

[0135] This is a second-order ordinary differential equation, which can be transformed into a system of first-order equations:

[0136] Let y1 = x, y2 = dx / dt, then we have:

[0137]

[0138] The solution is obtained using the RK4 method, following the same steps as above.

[0139] 7. Speed ​​equation of the switching mechanism:

[0140] This equation can be obtained directly from the solution of the displacement equation, i.e., v(t) = y2(t).

[0141] 8. Acceleration equation of the switching mechanism:

[0142] Acceleration can be obtained by numerically differentiating the velocity. Using the central difference method:

[0143] Where h is the time step.

[0144] 9. Circuit breaker spring vibration equation:

[0145] Similarly, the second-order equation is transformed into a system of first-order equations:

[0146] Let y1 = y, y2 = dy / dt, then we have:

[0147]

[0148] The solution is obtained using the RK4 method, following the same steps as above.

[0149] 10. Vibration equation of circuit breaker damper:

[0150] This is also transformed into a system of first-order equations:

[0151] Let y1 = z, y2 = dz / dt, then we have:

[0152]

[0153]

[0154] The solution is obtained using the RK4 method, following the same steps as above.

[0155] For each equation, we need to:

[0156] 1. Set initial conditions

[0157] 2. Select an appropriate time step h

[0158] 3. Define the time interval [0, T]

[0159] 4. Apply the RK4 method to each time step.

[0160] 5. Store the results at each time step.

[0161] 6. Perform interpolation as needed to obtain more accurate results.

[0162] Optionally, this process needs to be implemented using a programming language (such as Python, MATLAB, etc.) to perform iterative calculations and data processing. In practical applications, issues such as numerical stability, computational efficiency, and error control also need to be considered.

[0163] The following provides the solution process for each equation, along with the calculation of the range. Due to the complexity of some equations, a complete analytical solution may not be possible; in these cases, approximate or partial analytical solutions will be provided.

[0164] 1. Analytical solution to the three-phase voltage equation:

[0165]

[0166] This equation is already in analytical form and does not require further solution.

[0167] Range calculation: Three-phase voltage peak range: [U m -3σ,U m +3σ], where σ is the standard deviation of ε(t);

[0168] For example, preset initial conditions: U m =8200V (peak), f=50Hz, U d c = 100V, τ = 0.01s; therefore, considering the influence of harmonics and DC components, the actual three-phase voltage peak range is: [7800V, 8600V].

[0169] 2. Analytical solution to the three-phase current equation:

[0170]

[0171] This equation contains derivative terms and requires solving a differential equation:

[0172] Let y(t) = I φ (t), then:

[0173]

[0174] Using the integral factor method, the integral factor is: Solving for:

[0175]

[0176] Where C is the integration constant, which is determined by the initial conditions.

[0177] Range calculation: Three-phase current peak range: [I m -3σ I ,I m +3σ I ], where σ I Let η(t) be the standard deviation.

[0178] For example, preset initial conditions: I m =1000A (peak value), I d c = 10A, τ I =0.005s,K t =0.001s; therefore, considering the influence of harmonics and DC components, the actual peak value range of the three-phase current is: [950A, 1050A].

[0179] 3. Analytical solution to the equation for the operating current of the switching mechanism:

[0180]

[0181] This equation depends on the displacement function x(t), and the displacement equation needs to be solved first. Assuming that an analytical solution to x(t) has been obtained, it can be substituted into this equation.

[0182] Due to the nonlinear nature of the sign function, a complete analytical solution may be difficult to obtain. A piecewise function form can be considered:

[0183] When dx(t) / dt>0:

[0184]

[0185] When dx(t) / dt < 0:

[0186]

[0187] Range calculation: Maximum operating current range of the switching mechanism: [I0+I e -3σ o p,I0+I e +K m ·a max +K v ·v max +K s ·x max +I f +3σ o p]; where a max ,v max ,x max These represent maximum acceleration, velocity, and displacement, respectively, v o p is the standard deviation of ξ(t);

[0188] For example, the initial conditions are preset as follows: I0 = 50A,K m =0.1kg,K v =10 N·s / m, K s =1000N / m,I f =5A,I e =20A,τ e =0.01s, then the maximum range of the actual switching mechanism operating current is: [65A, 150A].

[0189] 4. Analytical solution to the operating voltage equation of the switching mechanism:

[0190]

[0191] This equation depends on I op x(t) and x(t). Assuming that we have obtained the analytical solutions to these two functions, substitute them into this equation.

[0192] For μ(t), assume it is a constant μ. Then the analytical solution is in the form of:

[0193]

[0194] Range calculation: Maximum operating voltage range of the switching mechanism: [U0-R] c ·I max -L c ·(dI / dt) max -K b ·a max -μU0-3σ U ,U0+3σ U Among them, I max ,(dI / dt) max ,a max These represent the maximum current, the maximum rate of change of current, and the maximum acceleration, respectively, σ U Let ζ(t) be the standard deviation.

[0195] For example, preset initial conditions: U0 = 220V, R c =0.1Ω,L c =0.001H,K b =0.05V·s² / m, μ=0.05,ω v =100πrad / s; then the maximum range of the operating voltage of the switching mechanism is: [180V, 230V].

[0196] 5. Analytical solution to the current and voltage equations during the contact opening and closing process:

[0197] Current equation:

[0198] I c (t)=I a e -t / τa sin(ω a t)+I b (1-e -t / τb )+I arc tanh(K arc t)+γ(t);

[0199] This equation is already in analytical form and does not require further solution.

[0200] Voltage equation:

[0201]

[0202] This equation depends on I c (t) and l arc (t). Assume l arc (t)=l0+varc ·t, where l0 is the initial arc length, v arc It is the speed at which the electric arc extends.

[0203] Range calculation: Maximum current range during contact opening and closing process: [I b -3σ γ ,I a +I b +I arc +3σ γ ], where σ γ The standard deviation of γ(t); the maximum voltage range during the contact opening and closing process: [U b -3σ δ U a +U b +U arc ·l max / (I min +I0)+3σ δ ], where σ δ Let l be the standard deviation of δ(t). max For the maximum arc length, I min This is the minimum current value;

[0204] For example, preset initial conditions: I a =1000A,τ a =0.005s,ω a =1000πrad / s,I b =500A,τ b =0.01s,I arc =100A,K arc =100s⁻¹, U a =1000V,τ c =0.005s,U b =500V,τ d =0.01s,U arc =20V, l0=0.001m, v arc =10m / s, I0=1A, then the maximum current range of the actual contact opening and closing process is: [450A, 1650A].

[0205] 6. Analytical solution to the displacement equation of the switching mechanism:

[0206]

[0207] This is a nonlinear second-order differential equation, and a complete analytical solution is difficult to obtain. Linearization approximation or piecewise linearization can be considered.

[0208] Assuming the friction term can be approximated as linear damping, i.e.:

[0209] make The equation then simplifies to:

[0210]

[0211] This is a standard second-order linear differential equation, and its analytical solution is:

[0212]

[0213] in C1 and C2 are determined by the initial conditions, x p F(t) is a particular solution, which depends on the specific form of F(t).

[0214] Range calculation: Maximum displacement range of the switching mechanism: [-x max ,x max ], where x max The equations can be solved numerically.

[0215] For example, the initial conditions are preset as follows: ζ = 0.1, ω n =100 rad / s, m ​​= 10 kg, F f =50N, k=10000N / m, A e =0.1m,ω e =50rad / s; therefore, the maximum displacement range of the switching mechanism is: [-0.05m, 0.05m].

[0216] 7. Analytical solution to the velocity equation of the switching mechanism:

[0217] Since velocity is the derivative of displacement, therefore:

[0218]

[0219] Range calculation: Maximum speed range of the switching mechanism: [-v max ,v max ], where v max The equations can be solved numerically to obtain the maximum speed range of the switching mechanism, for example, the maximum speed range is [-5 m / s, 5 m / s].

[0220] 8. Analytical solution to the acceleration equation of the switching mechanism:

[0221] Acceleration is the derivative of velocity, which can be obtained by differentiating the velocity equation again. Due to the complexity of the expression, the specific form is omitted here.

[0222] Range calculation: Maximum acceleration range of the switching mechanism: [-a max ,a max ], where a maxThe equation can be obtained by solving it numerically, for example, [-500 m / s 2 500 m / s 2 ].

[0223] 9. Analytical solution to the equation of motion for circuit breaker spring vibration:

[0224]

[0225] This is a linear second-order differential equation, and its homogeneous solution is:

[0226]

[0227] in D_1 and D_2 are determined by the initial conditions.

[0228] The particular solution depends on the specific form of F_s(t). Assuming F_s(t) = F_0 (a constant), the particular solution takes the form:

[0229]

[0230] Where B1 and B2 are constants, they can be solved by substituting them into the original equation. λ (t) is a particular solution caused by the random perturbation λ(t).

[0231] The complete solution is: y(t) = y h (t)+y p (t);

[0232] Range calculation: Circuit breaker spring vibration frequency range: [ω s (1-3σ ω ),ω s (1+3σ ω )], where σ ω The standard deviation of the frequency;

[0233] For example, the initial condition is preset as follows: ζ s =0.05,ω s =200 rad / s, m s =1kg, F0=100N, A s =0.01m,α s =10s - 1. The frequency range of the circuit breaker spring vibration is [190 rad / s, 210 rad / s].

[0234] 10. Analytical solution to the vibration equation of a circuit breaker damper:

[0235]

[0236] This is a nonlinear equation, and a complete analytical solution is difficult to obtain. A linear approximation can be considered:

[0237] Assume that the nonlinear damping term can be approximated as linear damping:

[0238] The simplified equation is:

[0239]

[0240] The homogeneous solution is:

[0241]

[0242] in E_1 and E_2 are determined by the initial conditions.

[0243] The particular solution depends on the specific form of F_d(t). Assuming F_d(t) = F_d0 (a constant), the particular solution takes the form:

[0244]

[0245] C1 and C2 are constants, which can be solved by substituting them into the original equation. p ρ(t) is a particular solution caused by the random perturbation ρ(t).

[0246] The complete solution is: z(t) = z h (t)+z p (t);

[0247] Range calculation: Vibration amplitude range of circuit breaker damper: [-z max ,z max ], where z max The equations can be solved numerically.

[0248] For example, the initial condition is preset as follows: ζ d =0.1,ω d =150 rad / s, m d =2kg,F d 0 = 200N,c d =0.5 N·s 2 / m 2 A d =0.02m,α d =5s - 1; then the actual vibration amplitude range of the circuit breaker damper is [-0.03 m, 0.03 m].

[0249] Summarize:

[0250] 1. For linear equations, a complete analytical solution can be obtained.

[0251] 2. For nonlinear equations, a linearization approximation is used to obtain an approximate analytical solution.

[0252] 3. In practical applications, it may be necessary to combine numerical methods to obtain more accurate solutions and range estimates.

[0253] 4. Range calculation takes into account the effects of random disturbances, and the 3σ principle is usually used to estimate the range.

[0254] 5. The preset initial conditions and parameter values ​​are based on assumptions and need to be adjusted according to the specific characteristics of the circuit breaker in actual applications.

[0255] 6. For complex coupled systems, it may be necessary to consider the mutual influence between the equations, which may require more advanced mathematical tools or numerical methods to handle.

[0256] These analytical solutions and range calculations provide a theoretical basis for fault mode identification of circuit breaker switching. In practical applications, it may be necessary to combine experimental data and statistical analysis to further optimize the model and parameter estimation.

[0257] Specifically, the principle of this invention is:

[0258] First, this method employs the concept of multi-source data fusion. By simultaneously collecting electrical and mechanical data, comprehensive monitoring of the circuit breaker's status is achieved. Electrical data includes three-phase voltage and current, as well as electrical parameters of the switching mechanism and contacts; these data reflect the circuit breaker's electrical performance and breaking capacity. Mechanical data includes the motion parameters of the switching mechanism and vibration signals from springs and dampers; these data reflect the circuit breaker's mechanical performance and operating characteristics. The integrated analysis of multi-source data provides a more comprehensive and accurate reflection of the circuit breaker's operating status, effectively avoiding the bias and inaccuracies that may result from a single data source.

[0259] Secondly, this method establishes an accurate mathematical model. By establishing sets of electrical and mechanical equations, the dynamic characteristics of the circuit breaker during opening and closing are accurately described. These equations consider various complex factors, such as nonlinear effects, random disturbances, and system coupling, and can more realistically reflect the physical process of the circuit breaker. Numerical and analytical solutions to the equations not only yield specific values ​​for key parameters but also their theoretical ranges of variation. This dual-solution method provides more fault characteristic information, which is beneficial for improving the accuracy and reliability of fault diagnosis.

[0260] Furthermore, this method employs advanced data processing and feature extraction techniques. Normalization eliminates the influence of different dimensions among parameters, ensuring comparability of features in subsequent analyses. Principal Component Analysis (PCA) enables dimensionality reduction and feature extraction from high-dimensional data. PCA identifies the main directions of change in the data, retains the most important information, and removes redundancy and noise. This not only reduces the computational complexity of subsequent processing but also improves the representativeness and discriminative power of the features.

[0261] Finally, this method uses a multilayer perceptron neural network as the fault identification model. Neural networks possess powerful nonlinear mapping capabilities and self-learning abilities, enabling them to effectively handle complex fault modes. Through a multilayer structure and nonlinear activation functions, the neural network can learn and represent complex feature combinations, adapting to the diversity and complexity of circuit breaker fault modes. This allows the model to directly output the probabilities of various fault modes, providing reliable quantitative indicators for fault diagnosis.

[0262] The technical solution of this invention is logically sound, mainly reflected in the following aspects:

[0263] 1. From data acquisition to feature extraction and then to fault identification, a complete fault diagnosis process has been constructed, with each link closely connected and logically rigorous.

[0264] 2. The electrical and mechanical characteristics of the circuit breaker are taken into account, and it conforms to the working principle and fault mechanism of the circuit breaker.

[0265] 3. The mathematical model and data processing methods used have a solid theoretical foundation and can effectively extract fault characteristics.

[0266] 4. The machine learning model used is suitable for handling complex nonlinear problems, which matches the needs of circuit breaker fault diagnosis.

[0267] In summary, the technical solution of this invention, through the organic combination of multi-source data fusion, precise mathematical modeling, advanced data processing, and intelligent recognition algorithms, constructs a comprehensive, accurate, and efficient circuit breaker fault diagnosis system, which can effectively solve the problems existing in the prior art and improve the accuracy and reliability of circuit breaker fault diagnosis.

[0268] To better understand and implement this invention, an example of a specific application scenario is provided below: A power distribution station has 10 circuit breakers, model ZN63A-12, with a rated current of 1250A.

[0269] 1. Installation and configuration of the data acquisition system

[0270] First, the company installed a data acquisition system on each circuit breaker. This system includes the following sensors:

[0271] Three-phase voltage transformer: model JDZX9-10, transformation ratio 10000 / 100V;

[0272] Three-phase current transformer: model LZZBJ9-10, transformation ratio 1250 / 5A;

[0273] Displacement sensor for switching mechanism: model WY-LD, measuring range 0-100mm;

[0274] Speed ​​sensor for switching mechanism: Model WY-CS, range ±10m / s;

[0275] Accelerometer sensor for switching mechanism: Model WY-CA, measuring range ±500m / s 2 ;

[0276] Spring vibration sensor: model WY-SV, frequency range 0-1000Hz;

[0277] Damper vibration sensor: model WY-DV, amplitude range ±50mm;

[0278] All sensors are connected to a central data acquisition unit, model WY-DAQ1000. The sampling rate of this unit is set to 10kHz to ensure that rapid transient changes during circuit breaker operation are captured.

[0279] 2. Data Acquisition Process

[0280] During a routine operation test, the operator performed opening and closing operations on circuit breaker No. 1. The data acquisition system recorded various parameters throughout the process. The following is a partial list of the acquired data (which has undergone preliminary processing, with a sampling interval of 1ms), as shown in Table 1:

[0281] Table 1 Data Collection Table

[0282]

[0283]

[0284] (Note: The complete dataset contains 1000 data points, covering the entire opening and closing process.)

[0285] 3. Equation Establishment and Solution

[0286] Based on the collected data, the system established a set of equations for electrical quantities and a set of equations for mechanical quantities.

[0287] These equations were solved using numerical methods (fourth-order Runge-Kutta method), and numerical and analytical solutions for each parameter were obtained.

[0288] 4. Determining the parameter range

[0289] By substituting the analytical solution into the preset initial conditions, the system obtained the range of each parameter:

[0290] Three-phase voltage peak range: [7800V, 8600V];

[0291] Three-phase current peak range: [950A, 1050A];

[0292] Maximum operating current range of the switching mechanism: [65A, 150A];

[0293] Maximum operating voltage range of the switching mechanism: [180V, 230V];

[0294] Maximum current range during contact opening and closing process: [450A, 1650A];

[0295] Maximum voltage range during contact opening and closing process: [450V, 1600V];

[0296] Maximum displacement range of the switching mechanism: [-0.05m, 0.05m];

[0297] Maximum speed range of the switching mechanism: [-5 m / s, 5 m / s];

[0298] Maximum acceleration range of the switching mechanism: [-500 m / s²] 2 500 m / s 2 ];

[0299] Circuit breaker spring vibration frequency range: [190 rad / s, 210 rad / s];

[0300] Vibration amplitude range of circuit breaker damper: [-0.03 m, 0.03 m];

[0301] 5. Data Normalization and Feature Extraction

[0302] The system normalizes the obtained numerical solutions and the maximum and minimum values ​​within the range, ensuring that all parameter values ​​fall within the [0,1] interval. Then, the system uses Principal Component Analysis (PCA) to extract features from the normalized data.

[0303] PCA analysis showed that the first five principal components explained 95% of the data variance. The system retained these five principal components, forming a 5x1000 feature matrix.

[0304] 6. Application of Fault Mode Recognition Model

[0305] A circuit breaker switch opening and closing fault mode recognition model based on Support Vector Machine (SVM) was trained. This model can identify the following 10 fault modes:

[0306] Normal operation, mechanical jamming, spring fatigue, damper failure, contact erosion, operating mechanism failure, auxiliary switch failure, coil failure, secondary circuit failure, insulation deterioration.

[0307] The system inputs the extracted feature matrix into this pre-trained SVM model. The model outputs a 10-dimensional fault mode vector:

[0308] [0.02,0.92,0.01,0.01,0.01,0.01,0.01,0.01,0.00,0.00];

[0309] This vector represents the probability of various fault modes. Based on the output, the system determines that the operating state of circuit breaker No. 1 is mechanical jamming, with a probability of 92%. Since the set safety threshold is 0.8, this indicates that the circuit breaker has low safety.

[0310] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for identifying the switch safety of a circuit breaker device, characterized in that, Includes the following steps: S10. Collect electrical and mechanical quantity data during the opening and closing process of the circuit breaker switch. The electrical quantity data includes: three-phase voltage and current waveform of the circuit breaker, operating current and voltage waveform of the switching mechanism, and current and voltage parameters of the contacts during the opening and closing process. The mechanical quantity data includes displacement, velocity, and acceleration curves of the switching mechanism, as well as vibration signals of the springs and dampers of the circuit breaker. S20. Establish a set of electrical quantity equations, including: three-phase voltage equations, three-phase current equations, switching mechanism operating current equations, switching mechanism operating voltage equations, and contact opening and closing process current and voltage equations. S30. Establish a set of mechanical quantity equations, including: the displacement equation of the switching mechanism, the velocity equation of the switching mechanism, the acceleration equation of the switching mechanism, the vibration equation of the circuit breaker spring, and the vibration equation of the circuit breaker damper. S40. Solve the set of electrical quantity equations to obtain multiple numerical solutions for electrical quantities, namely, the peak value of three-phase voltage, the peak value of three-phase current, the maximum value of the operating current of the switching mechanism, the maximum value of the operating voltage of the switching mechanism, the maximum value of the current during the contact opening and closing process, and the maximum value of the voltage during the contact opening and closing process. S50. Solve the set of mechanical quantity equations to obtain multiple numerical solutions for mechanical quantities, namely, the maximum displacement of the switching mechanism, the maximum velocity of the switching mechanism, the maximum acceleration of the switching mechanism, the vibration frequency of the circuit breaker spring, and the vibration amplitude of the circuit breaker damper. S60. Solve the electrical quantity equations analytically to obtain multiple analytical solutions for electrical quantities. Substitute these solutions into the preset initial conditions for electrical quantities to obtain multiple ranges of electrical quantities. S70. Solve the mechanical quantity equations analytically to obtain multiple analytical solutions for mechanical quantities. Substitute these solutions into the preset initial conditions for mechanical quantities to obtain multiple ranges of mechanical quantities. S80. Normalize the numerical solutions of the multiple electrical quantities, the numerical solutions of the multiple mechanical quantities, the maximum and minimum values ​​of the ranges of the multiple electrical quantities and the maximum and minimum values ​​of the ranges of the multiple mechanical quantities, so that all parameter values ​​fall within the [0,1] interval. Then, concatenate the normalized data and extract features through principal component analysis or dimensionality reduction methods to obtain a feature matrix. S90. Input the feature matrix into the pre-trained circuit breaker switch opening and closing fault mode recognition model to obtain the circuit breaker switch opening and closing fault mode vector. Compare the highest fault probability in the fault mode vector with a pre-set safety threshold. If the highest fault probability is greater than the safety threshold, the circuit breaker is determined to have low switch safety; otherwise, the circuit breaker is determined to have high switch safety.

2. The method for identifying the switch safety of a circuit breaker device according to claim 1, characterized in that, The analytical solutions for the multiple electrical quantities are: analytical expression for three-phase voltage, analytical expression for three-phase current, analytical expression for operating current of switching mechanism, analytical expression for operating voltage of switching mechanism, analytical expression for current during contact opening and closing process, and analytical expression for voltage during contact opening and closing process.

3. The method for identifying the switch safety of a circuit breaker device according to claim 2, characterized in that, The ranges of the electrical quantities are: the peak range of three-phase voltage, the peak range of three-phase current, the maximum range of operating current of the switching mechanism, the maximum range of operating voltage of the switching mechanism, the maximum range of current during contact opening and closing, and the maximum range of voltage during contact opening and closing.

4. The method for identifying the switch safety of a circuit breaker device according to claim 3, characterized in that, The ranges of the various mechanical quantities are: the maximum displacement range of the switching mechanism, the maximum speed range of the switching mechanism, the maximum acceleration range of the switching mechanism, the vibration frequency range of the circuit breaker spring, and the vibration amplitude range of the circuit breaker damper.

5. The method for identifying the switch safety of a circuit breaker device according to claim 4, characterized in that, The three-phase voltage equation is specifically expressed as follows: ； In the formula, It is a function of the voltage of a certain phase as a function of time; The fundamental amplitude is obtained by measuring it using a voltage transformer. Angular frequency, equal to , For system frequency; It is a time variable; The initial phase angle is determined by a synchronous measuring device; The amplitude of the nth harmonic is obtained through Fourier analysis; The initial phase angle of the nth harmonic; The highest harmonic order is considered; The DC bias component is detected by a voltage measuring device. It is a time constant and is related to the system impedance; For random noise; The three-phase current equation is specifically expressed as follows: ； In the formula, It is a function of the current in a certain phase as a function of time; The fundamental amplitude is obtained by measuring it using a current transformer. The power factor angle is measured using a power analyzer. The amplitude of the nth harmonic is obtained through Fourier analysis; The phase difference of the nth harmonic; The DC bias component is detected by a current measuring device. This is the current time constant, which is related to the system impedance and inductance. This is the eddy current coefficient, which is related to the circuit breaker core material; This is a random noise term.

6. The method for identifying the switch safety of a circuit breaker device according to claim 5, characterized in that, The operating current equation of the switching mechanism is specifically expressed as follows: ； In the formula, This refers to the operating current of the switching mechanism; The initial current is determined by the initial state of the operating mechanism; This is a mass coefficient, related to the mass of the moving parts of the operating mechanism; Let the displacement function of the switching mechanism be used. This is the velocity damping coefficient, which is related to the friction of the operating mechanism; The spring stiffness coefficient is determined by the spring characteristics of the operating mechanism; It is the Coulomb tribocurrent, which is related to the material of the contact surface. It is a symbolic function; This represents the amplitude of the eddy current. The eddy current time constant; For random noise; The operating voltage equation of the switching mechanism is specifically expressed as follows: ； In the formula, This is the operating voltage of the switching mechanism; Rated operating voltage; The equivalent resistance of the operating circuit; The equivalent inductance of the operating circuit; The back electromotive force coefficient; This is a voltage fluctuation function to simulate power grid fluctuations. The voltage fluctuation angular frequency; This is a random noise term.

7. The method for identifying the switch safety of a circuit breaker device according to claim 6, characterized in that, The current and voltage equations for the contact opening and closing process are specifically expressed as follows: ； ； In the formula, , For contact current and voltage; , These are the initial current and voltage amplitudes; , The current and voltage decay time constants; It is the angular frequency of the current oscillation; , These are the steady-state current and voltage components; , These are the rise time constants for current and voltage; , These are the characteristic values ​​of the arc current and voltage; This is the arc formation rate coefficient; It is a function of the arc length; The current constant is small to prevent division by zero errors; , This is a random noise term.

8. The method for identifying the switch safety of a circuit breaker device according to claim 7, characterized in that, The displacement equation of the switching mechanism is specifically expressed as follows: ； In the formula, For the displacement of the switching mechanism; The damping ratio; It is the natural angular frequency; The driving force function; For the quality of the switching mechanism; Friction; For spring stiffness; This refers to the amplitude of external vibration. The external vibration angular frequency; For random perturbations; The speed equation of the switching mechanism is specifically expressed as follows: ； In the formula, For the speed of the switching mechanism; The initial velocity; The damping coefficient is equal to ; The phase angle is equal to ; For random velocity perturbations; The acceleration equation of the switching mechanism is specifically expressed as follows: ； In the formula, Acceleration of the switching mechanism; For acceleration random perturbation; The circuit breaker spring vibration equation is specifically expressed as follows: ； In the formula, This represents the spring displacement. The spring damping ratio; The natural angular frequency of the spring; The external force acting on the spring; The equivalent mass of the spring; This represents the initial amplitude of the spring's vibration. This is the spring vibration attenuation coefficient; The spring vibration is a random disturbance; The vibration equation of the circuit breaker damper is specifically expressed as follows: ； In the formula, This represents the damper displacement. The damping ratio of the damper; The natural angular frequency of the damper; The external force acting on the damper; For the mass of the damper; The nonlinear damping coefficient; This represents the initial vibration amplitude of the damper. The damper vibration attenuation coefficient; This refers to random disturbances in the damper's vibration.

9. The method for identifying the switch safety of a circuit breaker device according to claim 8, characterized in that, The training steps for the circuit breaker switch opening and closing fault mode recognition model specifically include: Establish a training dataset, specifically by acquiring electrical and mechanical quantity data during the opening and closing process of circuit breaker switches with multiple known faults, and generating a feature matrix according to steps S10 to S80. The input to the training is the generated feature matrix, and the output of the training is the known fault. Network training: A multilayer perceptron network is trained using the training dataset to obtain the circuit breaker switch opening and closing fault mode recognition model.

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