A DC circuit breaker active protection method and system

Abstract

The present invention discloses a DC circuit breaker active protection method and system, which relates to the field of power protection technology, including real-time acquisition of original signals of DC lines, preprocessing of original signals; establishing a dynamic multidimensional threshold model based on the preprocessed original signals and historical current signals, generating dynamic multidimensional thresholds; combining the dynamic multidimensional thresholds and the preprocessed original signals, calculating overload indexes, dividing current overload stages, and outputting current overload signals; performing high-frequency oscillation detection on the preprocessed original signals according to the current overload signals, obtaining high-frequency oscillation abnormal signals; disconnecting the DC circuit through a fast disconnection mechanism according to the high-frequency oscillation abnormal signals, obtaining disconnection fault information; performing functional self-checking according to the disconnection fault information, and restoring the disconnected DC circuit. The present invention solves the problems of untimely response and inaccurate fault identification of traditional protection mechanisms by combining dynamic multidimensional threshold models and high-frequency oscillation detection.

Description

Technical Field

[0001] The present invention relates to the technical field of power protection, and in particular to a method and system for active protection of a DC circuit breaker. Background Art

[0002] DC power systems have been widely used in recent years, especially in the fields of photovoltaic and wind power generation, electric vehicles and energy storage systems. Compared with traditional AC power systems, DC power systems have higher energy efficiency, less transmission loss and better compatibility with electronic equipment. However, with the expansion of the scale and application of DC power systems, their stability and safety issues have gradually emerged. Overload, short circuit and other fault conditions in the DC circuit often cause serious consequences such as equipment damage and system shutdown. Therefore, how to ensure that the DC power system can quickly cut off the fault circuit when a fault occurs to avoid further damage has become an important issue that needs to be solved urgently.

[0003] At present, the research and application of DC circuit breakers are mainly focused on overload protection and short-circuit protection mechanisms. Traditional overload protection usually relies on a set fixed current threshold, and the disconnection action is triggered when the current exceeds the set threshold. This method has certain limitations because it cannot take into account current fluctuations and dynamic changes in the system, which can easily lead to excessive or false disconnection. In addition, traditional short-circuit protection mechanisms are mostly based on the detection of rapid current rise, but the response to complex high-frequency oscillation signals is not sensitive enough, resulting in the inability to accurately identify some specific fault modes. In the prior art, overload protection and short-circuit protection mechanisms often operate separately, and fail to effectively combine the real-time dynamic characteristics of the system, so it is impossible to achieve more accurate fault detection and protection. Summary of the invention

[0004] In view of the above existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a DC circuit breaker active protection method to solve the problems of untimely response and inaccurate fault identification of traditional protection mechanisms.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a method for active protection of a DC circuit breaker, comprising: real-time acquisition of original signals of a DC line, and preprocessing of the original signals; establishing a dynamic multidimensional threshold model based on the preprocessed original signals and historical current signals, and generating a dynamic multidimensional threshold; combining the dynamic multidimensional threshold and the preprocessed original signals, calculating an overload index, dividing the current overload stage, and outputting a current overload signal; based on the current overload signal, performing high-frequency oscillation detection on the preprocessed original signals to obtain a high-frequency oscillation abnormal signal; based on the high-frequency oscillation abnormal signal, disconnecting the DC circuit through a fast disconnection mechanism to obtain disconnection fault information; performing a functional self-check based on the disconnection fault information, and restoring the disconnected DC circuit.

[0008] As a preferred solution of the active protection method of the DC circuit breaker of the present invention, the real-time acquisition of the original signal of the DC line and the preprocessing of the original signal are specifically performed as follows:

[0009] Collect the original signal of the DC line through current and voltage sensors;

[0010] Use a digital-to-analog converter to convert the original signal from analog to digital;

[0011] Use a low-pass filter to remove the high-frequency noise in the original signal;

[0012] The gain of the original signal is adjusted through the gain amplifier;

[0013] Use mean filtering algorithm to remove random noise from the original signal;

[0014] Adjust the sensor gain and bias parameters to calibrate and calibrate the original signal;

[0015] The processed original signal is transmitted to the data processing unit via the I2C bus;

[0016] The original signal includes a current signal and a voltage signal.

[0017] As a preferred solution of the active protection method of the DC circuit breaker of the present invention, wherein: the dynamic multidimensional threshold model is established based on the preprocessed original signal and the historical current signal to generate the dynamic multidimensional threshold, and the specific steps are:

[0018] A dynamic multidimensional threshold model is established based on the preprocessed original signal and historical current signal. The expression is:

[0019] ;

[0020] in, is a dynamic multidimensional threshold, For the current moment, is the current average value parameter, For the current moment The sliding average of the collected current signal, is the weight coefficient of the current signal fluctuation range, is the number of sampling points of the sliding window, is the sampling point index, is the time sampling point in the current time window, is the current signal collected at the time sampling point in the current time window, is the historical current trend weight coefficient, is the historical current trend integral term, is the length of the historical window, For the current moment The collected current signal, is the small time step of the time integration;

[0021] The preprocessed original signal and the historical current signal are input into the dynamic multidimensional threshold model to calculate the dynamic multidimensional threshold.

[0022] As a preferred solution of the active protection method of the DC circuit breaker of the present invention, wherein: the above steps of combining the dynamic multi-dimensional threshold and the pre-processed original signal, calculating the overload index, dividing the current overload stage, and outputting the current overload signal are as follows:

[0023] Through the difference between the current signal in the preprocessed original signal and the dynamic multi-dimensional threshold, and introducing the dynamic adjustment factor, the overload index function is constructed to quantify the overload degree and calculate the overload index. The expression is:

[0024] ;

[0025] in, For the current moment The overload index, For the current moment The collected current signal, is a dynamic multidimensional threshold, is the nonlinear amplification factor of the overload index, is the dynamic adjustment factor, is the natural base, For the current moment The first derivative of the acquired current signal, is the decay rate of the rate of change to the exponential factor, For the current moment The absolute value of the first derivative of the collected current signal;

[0026] Based on the value range of the overload index, the current overload stage is divided into normal operation, slight overload, moderate overload and severe overload;

[0027] According to the calculated overload index and combined with the current overload stage division, a current overload signal is output.

[0028] As a preferred solution of the active protection method of a DC circuit breaker of the present invention, wherein: according to the current overload signal, the pre-processed original signal is subjected to high-frequency oscillation detection to obtain a high-frequency oscillation abnormal signal, and the specific steps are as follows:

[0029] Perform empirical mode decomposition on the current overload signal, retain the intrinsic mode function components containing high-frequency components, and extract the high-frequency component signal. The expression is:

[0030] ;

[0031] in, is the high frequency component signal, is the total number of modes decomposed, is the modal number index coefficient, is the first The intrinsic mode functions, For the The instantaneous frequency of an eigenmode function, is the high frequency threshold, is a Boolean indicator function;

[0032] The oscillation energy is calculated based on the high-frequency component signal and normalized. The expression is:

[0033] ;

[0034] in, is the normalized value of high-frequency oscillation energy, is the loss power of the high frequency component signal, is the instantaneous power of the original signal after preprocessing, The length of the time window for energy calculation;

[0035] The degree of high-frequency oscillation is determined based on the oscillation energy, and a high-frequency oscillation abnormality signal is output.

[0036] As a preferred solution of the active protection method of the DC circuit breaker of the present invention, wherein: according to the high-frequency oscillation abnormal signal, the DC circuit is disconnected by a fast disconnection mechanism to obtain disconnection fault information, the specific steps are:

[0037] Determine whether a disconnection operation needs to be performed according to the high-frequency oscillation abnormal signal and the current overload signal;

[0038] When it is determined that the disconnection operation is not to be performed, the standby monitoring state is entered and the original signal is continued to be monitored;

[0039] When it is determined that a disconnection operation is to be performed, a disconnection instruction is sent to a drive unit of the circuit breaker, and current is cut off through an insulated gate bipolar transistor to disconnect the DC circuit;

[0040] After disconnecting the DC circuit, monitor the circuit breaker working status and obtain disconnection fault information.

[0041] As a preferred solution of the active protection method of the DC circuit breaker of the present invention, the specific steps of performing a functional self-check according to the disconnection fault information and restoring the disconnected DC circuit are as follows:

[0042] According to the disconnection fault information, the sensor, switch assembly and power supply are self-checked and a self-check result report is obtained;

[0043] Perform fault analysis and diagnosis based on the self-test result report, and formulate line recovery strategies according to the fault type;

[0044] Execute the recovery operation according to the line recovery strategy, enter the standby monitoring state, and continue to monitor the original signal.

[0045] In a second aspect, the present invention provides a DC circuit breaker active protection system, including an original signal acquisition module, a threshold model construction module, an overload stage division module, a high-frequency oscillation detection module, a circuit quick disconnect module and a fault self-detection and recovery module; the original signal acquisition module is used to collect the original signal of the DC line in real time and preprocess the original signal; the threshold model construction module is used to establish a dynamic multidimensional threshold model based on the preprocessed original signal and the historical current signal to generate a dynamic multidimensional threshold; the overload stage division module is used to combine the dynamic multidimensional threshold and the preprocessed original signal, calculate the overload index, divide the current overload stage, and output the current overload signal; the high-frequency oscillation detection module is used to perform high-frequency oscillation detection on the preprocessed original signal according to the current overload signal to obtain a high-frequency oscillation abnormal signal; the circuit quick disconnect module is used to disconnect the DC circuit through a quick disconnect mechanism according to the high-frequency oscillation abnormal signal to obtain disconnection fault information; the fault self-detection and recovery module is used to perform functional self-detection according to the disconnection fault information and restore the disconnection of the DC circuit.

[0046] In a third aspect, the present invention provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program is executed by the processor, any step of the DC circuit breaker active protection method as described in the first aspect of the present invention is implemented.

[0047] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, any step of the DC circuit breaker active protection method as described in the first aspect of the present invention is implemented.

[0048] The beneficial effects of the present invention are as follows: by real-time acquisition and preprocessing of the original signal of the DC line, a dynamic multi-dimensional threshold model is established in combination with historical data, the current overload stage is accurately divided and the overload index is quantified, thereby optimizing the accuracy of overload protection. By extracting abnormal signals through high-frequency oscillation detection technology, rapid response and early warning to current line fluctuations are achieved, and the sensitivity and accuracy of the protection mechanism are improved. Relying on the fast disconnect mechanism, the DC circuit can be quickly cut off when an abnormality is detected, avoiding potential line damage. By disconnecting the fault information for self-inspection and restoring the line, the self-healing ability and stability of the line are enhanced. The response speed, protection accuracy and line reliability of the circuit breaker active protection are improved, and the problems of false triggering, missed triggering and response delay in the prior art are solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0050] Figure 1 This is a flow chart of the active protection method for a DC circuit breaker in Example 1.

[0051] Figure 2 This is a module diagram of the DC circuit breaker active protection system in Example 1. DETAILED DESCRIPTION

[0052] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0053] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0054] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0055] Example 1, reference Figure 1 and Figure 2 , which is the first embodiment of the present invention, and provides a DC circuit breaker active protection method, comprising the following steps:

[0056] S1: collect the original signal of the DC line in real time and pre-process the original signal.

[0057] Specifically, the following steps are included:

[0058] S1.1: Collect the original signal of the DC line through current and voltage sensors.

[0059] Specifically, a Hall effect current sensor (such as ACS758) is used to collect current signals. Hall effect sensors have good isolation performance and high precision, can accurately measure a large current range (such as 0-500A) and provide linear output. A high-precision voltage sensor is used to collect voltage signals, such as LTC2990, which can accurately measure high voltages (such as above 500V) and has high linearity and low error characteristics.

[0060] S1.2: Use a digital-to-analog converter to convert the original signal from an analog signal to a digital signal.

[0061] Specifically, select a high-precision analog-to-digital converter (such as ADS1256, 24-bit ADC) with up to 30kSPS (sampling rate) and up to 24-bit resolution to ensure that the collected original signal has sufficient accuracy and high frequency response. Configure the ADC to continuous sampling mode to ensure the real-time nature of the original signal. The sampling frequency should be set to 2-5 times the current fluctuation frequency (for example, if the current frequency is 50Hz, the sampling frequency should be at least 250Hz).

[0062] S1.3: Remove the high-frequency noise in the original signal through a low-pass filter.

[0063] Specifically, a standard second-order Butterworth filter is used to remove high-frequency noise exceeding 1 kHz and retain the basic waveform of the original signal.

[0064] S1.4: The gain of the original signal is adjusted through the gain amplifier.

[0065] Specifically, use a programmable gain amplifier (PGA) such as INA333. Adjust the original signal amplitude by configuring the gain value. The gain should be set according to the output voltage range of the sensor and the input range of the ADC. Assuming the sensor output voltage is 0-3V and the ADC input range is 0-5V, you can choose a gain of 2 to maximize the original signal within the input range of the ADC.

[0066] S1.5: Use the mean filter algorithm to remove random noise from the original signal.

[0067] It should be understood that the mean filtering algorithm refers to a sliding window algorithm, which can effectively remove random noise generated by the sensor and sampling process.

[0068] S1.6: Adjust the sensor gain and bias parameters to calibrate and calibrate the original signal.

[0069] Specifically, a known 20A standard signal is provided by a known standard current source (such as a precision current generator) as a reference signal for calibration. During the calibration process, the gain factor of the gain amplifier and the bias voltage of the sensor are adjusted. By reversely adjusting the 20A standard signal, it is ensured that the original signal accurately reflects the actual current or voltage value. The calibration accuracy should be within 0.1%.

[0070] S1.7: The processed original signal is transmitted to the data processing unit via the I2C bus.

[0071] Specifically, the processed raw signal is sent to the main controller or data processing unit through the I2C bus. In the I2C protocol, the host controls the data transmission and uses SCL (clock line) and SDA (data line) to transmit data. After each data transmission, the receiver should confirm the received data through ACK. The I2C bus protocol supports multi-device communication and is suitable for low power consumption, short distances and multiple sensor devices.

[0072] S1.8: The original signal includes a current signal and a voltage signal.

[0073] It should be noted that the current signal is used to establish a dynamic multi-dimensional threshold model, and the voltage signal is used to verify the connectivity of the line to ensure the normal operation of the loop.

[0074] Preferably, the original signal of the DC line is collected in real time through accurate current and voltage sensors, and combined with high-precision analog-to-digital converters and processing methods such as filtering and gain adjustment to effectively eliminate noise and improve the accuracy of the original signal. The mean filter algorithm is used to remove random noise to ensure the stability of the original signal, and the acquisition accuracy is calibrated through sensor calibration. The processed original signal is transmitted to the data processing unit through the I2C bus to ensure real-time and high efficiency.

[0075] S2: A dynamic multidimensional threshold model is established based on the preprocessed original signal and the historical current signal to generate a dynamic multidimensional threshold.

[0076] Specifically, the following steps are included:

[0077] S2.1: A dynamic multidimensional threshold model is established based on the preprocessed original signal and historical current signal. The expression is:

[0078] ;

[0079] in, is a dynamic multidimensional threshold, For the current moment, is the current average value parameter, For the current moment The sliding average of the collected current signal, is the weight coefficient of the current signal fluctuation range, is the standard deviation of the current signal, indicating the degree of fluctuation of the current signal within the sliding window and reflecting the amplitude of the change of the current signal. is the number of sampling points of the sliding window, is the sampling point index, is the time sampling point in the current time window, is the current signal collected at the time sampling point in the current time window, is the historical current trend weight coefficient, It is the historical current trend integral item, which is used to reflect the historical change trend of the current signal, especially the large changes. is the length of the historical window, For the current moment The collected current signal, is the small time step size for the time integration.

[0080] Preferably, the core goal of the dynamic multidimensional threshold model is to dynamically generate a multidimensional threshold corresponding to the current moment based on the fluctuation, average value, standard deviation and historical trend information of the real-time current and voltage signals for subsequent current overload detection, protection control and fault warning.

[0081] S2.2: Input the preprocessed original signal and the historical current signal into the dynamic multidimensional threshold model to calculate the dynamic multidimensional threshold.

[0082] Specifically, the data required for calculation is extracted from the preprocessed original signal and the historical current signal (obtained from the historical signal cache or storage unit); the real-time current signal is used and historical current signals, and calculate the sliding average in a dynamic multidimensional threshold model , the expression is:

[0083] ;

[0084] Based on the number of sliding windows Calculate the standard deviation of the current signal. Through these calculations, the current fluctuation range and its changing trend can be obtained. Combine the average value of the current signal at the current moment and the fluctuation amplitude of the historical current signal, and substitute these values ​​into the formula. By adjusting the parameters and , fine-tune the calculation of dynamic thresholds to ensure that the dynamic multi-dimensional threshold reflects the fluctuation characteristics and change trend of the current signal. Calculate the historical change trend of the current through the integral term of the historical current signal, and use the historical current trend weight coefficient , combining historical trend factors with the fluctuation of the current original signal to calculate the final dynamic multidimensional threshold .

[0085] Preferably, by introducing a dynamic multi-dimensional threshold model, combined with the volatility of the real-time current signal, historical current trends and average values, the current overload threshold can be flexibly adjusted to accurately respond to current fluctuations and changes. The dynamic multi-dimensional threshold model provides a real-time, dynamically generated threshold by calculating the standard deviation, historical trends and instantaneous changes of the current signal, effectively avoiding the limitations of the traditional static threshold method. This solution can not only improve the accuracy, timeliness and adaptability of current overload detection, but also reduce false alarms and missed alarms, ensuring the reliability and flexibility of current overload protection in complex environments.

[0086] S3: Combine the dynamic multi-dimensional threshold and the pre-processed original signal to calculate the overload index, divide the current overload stage, and output the current overload signal.

[0087] Specifically, the following steps are included:

[0088] S3.1: By taking the difference between the current signal in the original signal after preprocessing and the dynamic multi-dimensional threshold and introducing the dynamic adjustment factor, an overload index function is constructed to quantify the overload degree and calculate the overload index. The expression is:

[0089] ;

[0090] in, For the current moment The overload index, For the current moment The collected current signal, is a dynamic multidimensional threshold, is the nonlinear amplification factor of the overload index, is the dynamic adjustment factor, is the natural base, For the current moment The first derivative of the acquired current signal, is the decay rate of the rate of change to the exponential factor, For the current moment The absolute value of the first derivative of the acquired current signal.

[0091] Preferably, the overload exponential function introduces a dynamic adjustment factor of the current change rate, so that the algorithm can have a higher sensitivity to rapidly changing current signals, thereby avoiding the problem of delayed response to sudden overload in traditional methods.

[0092] S3.2: Based on the value range of the overload index, the current overload stage is divided into normal operation, slight overload, moderate overload and severe overload.

[0093] Specifically, according to the overload index The value range is classified as follows:

[0094] : Normal operation, the line is not overloaded;

[0095] : Slight overload, enter the first level overload protection;

[0096] : Moderate overload, enter the second level overload protection;

[0097] : Severe overload, entering level 3 overload protection.

[0098] S3.3: Output a current overload signal according to the calculated overload index and the current overload stage division.

[0099] Specifically, according to the calculated overload index , output current overload signal in real time, and trigger corresponding protection mechanism according to overload level. The specific operation is as follows:

[0100] like , output normal operating signal and continue to monitor the current signal;

[0101] like , output a slight overload signal, triggering the first-level protection mechanism: record the overload time, continuously monitor whether to increase further;

[0102] like , output moderate overload signal, triggering the secondary protection mechanism: shortening the monitoring cycle and issuing an alarm signal at the same time;

[0103] like , outputs a severe overload signal, triggering the third-level protection mechanism: immediately sending a quick disconnect command to the circuit breaker drive module.

[0104] Preferably, accurate detection and real-time response to the current overload state can be achieved by combining the dynamic multidimensional threshold model and overload index calculation. According to the difference between the current signal and the dynamic multidimensional threshold, the overload index is constructed in combination with the current change rate, and a dynamic adjustment factor is introduced to improve the algorithm's sensitivity to rapid current changes. Through the value range classification of the overload index, the current overload state is divided into four stages: normal operation, mild overload, moderate overload and severe overload, and the corresponding protection mechanism is triggered according to the stage. This solution can flexibly adjust the protection strategy according to the degree of overload, ensure timely warning at the early stage of overload, quickly disconnect the current in case of severe overload, avoid equipment damage and improve line safety.

[0105] S4: According to the current overload signal, a high-frequency oscillation detection is performed on the preprocessed original signal to obtain a high-frequency oscillation abnormal signal.

[0106] Specifically, the following steps are included:

[0107] S4.1: Perform empirical mode decomposition on the current overload signal, retain the intrinsic mode function components containing high-frequency components, and extract the high-frequency component signal. The expression is:

[0108] ;

[0109] in, is the high frequency component signal, is the total number of modes decomposed, is the modal number index coefficient, is the first The intrinsic mode functions, For the The instantaneous frequency of an eigenmode function, is the high frequency threshold, is a Boolean indicator function.

[0110] Specifically, The calculation expression is:

[0111] ;

[0112] in, is the instantaneous phase, For the The first derivative of the IMF component.

[0113] Preferably, the high-frequency component signal is extracted through the above expression The method of combining empirical mode decomposition with instantaneous frequency analysis is different from the traditional fixed bandpass filter and can dynamically adapt the oscillation frequency range to avoid the limitations of filter design.

[0114] S4.2: Calculate the oscillation energy based on the high-frequency component signal and normalize the oscillation energy. The expression is:

[0115] ;

[0116] in, is the normalized value of high-frequency oscillation energy, is the loss power of the high frequency component signal, is the instantaneous power of the original signal after preprocessing, The length of the time window for energy calculation.

[0117] Preferably, the influence of different current amplitudes on the calculation of high-frequency oscillation energy is eliminated through normalization processing, so that the calculation result of high-frequency oscillation energy has universal applicability.

[0118] S4.3: Determine the degree of high-frequency oscillation based on the oscillation energy and output a high-frequency oscillation abnormality signal.

[0119] Specifically, The range of is [0,1], where:

[0120] : Normal signal, no significant high-frequency oscillation;

[0121] : Slight high-frequency oscillation, record abnormal time and continue monitoring;

[0122] : Moderate high-frequency oscillation, triggering an alarm and shortening the monitoring period;

[0123] : Severe high-frequency oscillation, immediately triggering high-frequency abnormal signal and starting the quick disconnect mechanism.

[0124] Preferably, by combining empirical mode decomposition and instantaneous frequency analysis, the high-frequency components in the current signal are dynamically extracted, overcoming the limitations of traditional fixed-frequency bandpass filters and enhancing the sensitivity to high-frequency oscillations. By calculating the energy of high-frequency oscillations and normalizing them, the oscillation energy at different current amplitudes is made comparable, thereby effectively quantifying the oscillation intensity. According to the oscillation energy value, the high-frequency oscillation is divided into different degrees, and corresponding response measures are taken, such as alarm, shortening of monitoring cycle or fast disconnection protection mechanism. This method can dynamically adapt to line frequency changes, improve the detection accuracy and response efficiency of high-frequency oscillations, and ensure strong protection capabilities and adaptability under different current conditions.

[0125] S5: According to the high-frequency oscillation abnormal signal, the DC circuit is disconnected through a quick disconnection mechanism to obtain disconnection fault information.

[0126] Specifically, the following steps are included:

[0127] S5.1: Determine whether a disconnection operation needs to be performed based on the high-frequency oscillation abnormality signal and the current overload signal.

[0128] Specifically, if the high-frequency oscillation abnormal signal is a severe high-frequency oscillation ( ) or the current overload signal is severe overload ( ), it is considered an abnormal situation and a disconnection operation needs to be performed;

[0129] If the high-frequency oscillation abnormal signal is not a severe high-frequency oscillation ( ) or the current overload signal is not a severe overload ( ), no disconnection is required.

[0130] S5.2: When it is determined that the disconnection operation is not to be performed, the system enters the standby monitoring state and continues to monitor the original signal.

[0131] Specifically, if it is determined that the current state does not require a disconnection operation, the system enters a standby state, keeps continuously monitoring the current signal, the voltage signal, and the oscillation signal, and waits for the next trigger.

[0132] S5.3: When it is determined that a disconnection operation is to be performed, a disconnection instruction is sent to a drive unit of the circuit breaker, and current is cut off through an insulated gate bipolar transistor to disconnect the DC circuit.

[0133] Specifically, a disconnection command is issued from the monitoring unit, and the command is transmitted to the circuit breaker drive unit through a communication interface (such as an I2C bus). After receiving the command, the circuit breaker drive unit drives the insulated gate bipolar transistor (IGBT) or other solid-state switching device through the control command to cut off the current. The switching operation of the IGBT switching device can instantly interrupt the current path, quickly cut off the DC circuit, and prevent electrical fires or equipment damage caused by overload or oscillation.

[0134] Furthermore, IGBT is selected due to its high efficiency, fast response and low conduction loss.

[0135] S5.4: After disconnecting the DC circuit, monitor the circuit breaker working status and obtain disconnection fault information.

[0136] Specifically, after the disconnection operation, continue to monitor the working status of the circuit breaker to ensure that it is successfully disconnected and in a safe state. The switch position (open or closed) and operating status of the circuit breaker are monitored by sensors to ensure stable transmission feedback of fault information. The status information of the circuit breaker is fed back to the main control unit through the I2C bus. The main control unit determines whether the disconnection is successful by obtaining feedback and triggers subsequent operations. If the circuit breaker fails to disconnect successfully, the fault information should be recorded and output, such as the fault code, current signal, voltage signal, etc. of the circuit breaker, to facilitate later fault diagnosis. If the disconnection operation is successful, a functional self-check is performed to try to restore the line; if the disconnection fails, an alarm is issued and further fault handling is taken (retry disconnection or manual intervention).

[0137] Preferably, by accurately judging high-frequency oscillation and current overload signals, a quick disconnect operation is implemented to ensure that the circuit breaker quickly cuts off the DC circuit under abnormal conditions to prevent equipment damage or fire risks. An IGBT solid-state switch is used to achieve efficient disconnection, and enters the standby monitoring state when disconnection is not required to ensure continuous monitoring of the line. After disconnection, the circuit breaker status is monitored through real-time feedback. If the operation fails, the fault information is recorded and further measures are taken. This mechanism improves the overall safety, reliability and intelligent fault diagnosis capabilities, effectively reduces the risk of electrical fires and equipment damage, ensures stable operation of the line and improves fault handling efficiency.

[0138] S6: Perform a functional self-check based on the disconnection fault information and restore the disconnected DC circuit.

[0139] Specifically, the following steps are included:

[0140] S6.1: Perform self-inspection on the sensor, switch assembly and power supply according to the disconnection fault information, and obtain a self-inspection result report.

[0141] Specifically, the sensor output is compared through the built-in test circuit to verify the accuracy and response of the sensor. If the test result deviation exceeds the set range (for example, the voltage is not 500V, or the current deviates too far from the standard value of 20A), it is marked as a fault. Check whether the temperature sensor can accurately read the device temperature to prevent safety problems caused by excessive temperature. Send a test command to the drive unit to check whether the switching element can receive the command and perform the operation within the normal time. By simulating the current disconnection, verify whether components such as IGBT can effectively interrupt the current. Ensure that the power output is stable and there is no excessive current or unstable voltage. For lines that require backup power support, check whether the battery is sufficient and whether the backup power is in standby mode.

[0142] S6.2: Perform fault analysis and diagnosis based on the self-test result report, and formulate a line recovery strategy based on the fault type.

[0143] Specifically, if a sensor failure is detected (such as failure of the current or voltage sensor), you can try to restart the sensor or replace it with a backup sensor. If the sensor failure cannot be repaired, manual intervention is required and an alarm notification is issued. If a switch component (such as an IGBT) fails, the current path needs to be restored through a backup switch or a redundant circuit. The fault analysis report will check the internal state of the switch, such as whether the control instructions are correct and whether the switch can operate normally. If there is a problem with the power module, you need to check the power connection, battery status, and ensure that the battery is charging normally. If the main power cannot be restored, you can switch to the backup power supply or switch to the backup power channel.

[0144] S6.3: Execute the recovery operation according to the line recovery strategy, enter the standby monitoring state, and continue to monitor the original signal.

[0145] It should be understood that the standby monitoring state refers to the continuous monitoring of the original parameters to ensure the normal operation of the circuit breaker. And continuously report the current status to the central control unit to ensure that the monitoring data is updated in time and provide real-time feedback and alarm mechanism.

[0146] Preferably, a comprehensive self-check of sensors, switch components, and power supplies can ensure that faults can be discovered and handled in a timely manner to avoid recovery failures caused by hardware problems. Analysis of self-check results helps to accurately diagnose the type of fault and select the most appropriate recovery strategy, such as restarting sensors, switching backup switches or power supplies, etc., to ensure that the line is quickly restored to operation. After entering the standby monitoring state, sensors continuously monitor key parameters and provide real-time feedback to ensure the stability of the current path and power supply. Through redundant design and backup components, a smooth transition can be achieved in the event of a fault, reducing downtime and improving safety, ultimately achieving efficient, stable, and reliable fault recovery and safety assurance.

[0147] This embodiment also provides a DC circuit breaker active protection system, including:

[0148] The original signal acquisition module is used to collect the original signal of the DC line in real time and pre-process the original signal;

[0149] A threshold model building module is used to establish a dynamic multi-dimensional threshold model based on the pre-processed original signal and the historical current signal to generate a dynamic multi-dimensional threshold;

[0150] An overload stage division module is used to combine the dynamic multi-dimensional threshold and the pre-processed original signal, calculate the overload index, divide the current overload stage, and output the current overload signal;

[0151] The high-frequency oscillation detection module is used to perform high-frequency oscillation detection on the pre-processed original signal according to the current overload signal to obtain a high-frequency oscillation abnormal signal;

[0152] A circuit quick disconnect module is used to disconnect the DC circuit through a quick disconnect mechanism according to a high-frequency oscillation abnormal signal and obtain disconnection fault information;

[0153] The fault self-check and recovery module is used to perform a functional self-check according to the disconnection fault information and restore the disconnected DC circuit.

[0154] This embodiment also provides a computer device, which is applicable to the case of a DC circuit breaker active protection method, including: a memory and a processor; the memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions to implement the DC circuit breaker active protection method proposed in the above embodiment.

[0155] The computer device may be a terminal, and the computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device may be a touch layer covered on the display screen, or a key, trackball or touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse, etc.

[0156] This embodiment also provides a storage medium, on which a computer program is stored. When the program is executed by a processor, the method for realizing active protection of a DC circuit breaker as proposed in the above embodiment is realized; the storage medium can be realized by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (Static Random Access Memory, referred to as SRAM), electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, referred to as EEPROM), erasable programmable read-only memory (Erasable Programmable Read Only Memory, referred to as EPROM), programmable read-only memory (Programmable Red-Only Memory, referred to as PROM), read-only memory (Read-Only Memory, referred to as ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0157] In summary, the present invention optimizes the accuracy of overload protection by: real-time acquisition and preprocessing of the original signal of the DC line, combining historical data to establish a dynamic multi-dimensional threshold model, accurately dividing the current overload stage and quantifying the overload index. By extracting abnormal signals through high-frequency oscillation detection technology, rapid response and early warning to current line fluctuations are achieved, and the sensitivity and accuracy of the protection mechanism are improved. Relying on the fast disconnect mechanism, the DC circuit can be quickly cut off when an abnormality is detected, avoiding potential line damage. By disconnecting the fault information for self-inspection and restoring the line, the self-healing ability and stability of the line are enhanced. The response speed, protection accuracy and line reliability of the circuit breaker active protection are improved, and the problems of false triggering, missed triggering and response delay in the prior art are solved.

[0158] Example 2, referring to Table 1, is the second example of the present invention. To further verify the technical solution of the present invention, experimental simulation data of the active protection method of a DC circuit breaker are provided.

[0159] This embodiment verifies the actual performance of the active protection method of the DC circuit breaker under different load and fault conditions, especially in terms of current overload, high-frequency oscillation and line recovery response speed. The test scenario simulates an actual DC power line, in which common industrial loads (such as motors and power supply equipment) are used. The test equipment includes: a DC circuit breaker (including an IGBT switch module and a high-frequency oscillation monitoring module); a current and voltage sensor: used to collect current and voltage signals in real time; a digital-to-analog converter (ADC): converts analog signals into digital signals; a digital signal processing unit (DSP): performs real-time processing on the collected original signals; example loads: motors, DC power supplies, transformers, etc.; measurement tools: power analyzers, oscilloscopes. Overload and high-frequency oscillation under different load conditions are simulated, including common electrical faults such as current fluctuations, voltage instability, etc. In different tests, the protection performance of the present invention and the prior art is tested, including reaction time, cut-off effect and fault recovery speed.

[0160] The specific experimental steps are as follows: the original current and voltage signals are collected in real time through the current and voltage sensors, and the original signals are processed through the digital-to-analog converter. The collected original signals are subjected to low-pass filtering, gain adjustment, and mean filtering to remove noise and ensure the accuracy of the original signals. According to the preprocessed original signals and historical signals, the dynamic multidimensional threshold is calculated through the dynamic multidimensional threshold model, and compared with the current signal to judge the overload situation. By calculating and classifying the overload index, the current state of the line is judged to determine whether high-frequency oscillation detection is required. When high-frequency oscillation occurs in the line, the oscillation signal is extracted through empirical mode decomposition (EMD), and the normalized value of the high-frequency oscillation energy is calculated. If the normalized value of the high-frequency oscillation energy exceeds the set threshold, the disconnection operation is triggered. According to the abnormal high-frequency oscillation signal, an instruction is sent to the circuit breaker drive unit to quickly cut off the DC circuit and monitor the status of the disconnection operation. After disconnection, a self-test is performed, including the detection of sensors, switch components, and power supplies, and fault diagnosis and recovery operations are performed according to the self-test report.

[0161] The details are shown in Table 1 below:

[0162]

[0163] In the traditional circuit breaker protection method (test 2), the response time is generally long, and the disconnection time is between 150 milliseconds and 200 milliseconds. Even in the case of high-frequency oscillation or mild overload, the response time remains long, indicating that the traditional method has a slow protection reaction under high load conditions. In contrast, using the protection method of the present invention (tests 4 to 9), the disconnection time of the line is greatly shortened even in the case of severe overload or high-frequency oscillation. For example, in the case of severe overload (test 6), the disconnection time is 43 milliseconds, which is about 140 milliseconds less than the traditional technology. When high-frequency oscillation and severe overload occur simultaneously (test 8), the disconnection time remains at around 39 milliseconds, showing its extremely fast response capability.

[0164] In the conventional circuit breaker (test 3), although high-frequency oscillation is detected and the normalized value of high-frequency oscillation energy reaches 0.77, the disconnection operation is not effectively triggered, which may cause overheating or damage to the device. In the embodiment of the present invention, even in the case of severe overload and high-frequency oscillation (test 6 and test 7), the protection mechanism can be triggered in time and the current can be quickly disconnected through the dual judgment of overload index and oscillation energy.

[0165] The method of the present invention can trigger the disconnection operation within 40 milliseconds after high-frequency oscillation (test 7) ​​and severe overload (test 8), and the recovery process (test 9) can also be completed within 50 milliseconds. The line recovery speed is significantly better than the processing capacity of traditional circuit breakers. In particular, through functional self-checking and recovery, the line can be restored to working status in time without long-term shutdown.

[0166] The disconnection mechanism of traditional circuit breakers only relies on threshold detection or simple high-frequency oscillation detection, while the present invention can accurately determine when to perform the disconnection operation and maintain a short disconnection time in multiple complex situations by integrating dynamic multi-dimensional threshold models, overload index and oscillation energy. In addition, the line can self-check and recover, which greatly improves the safety and stability of the line.

[0167] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A DC circuit breaker active protection method, characterized in that: include, Collect the original signal of the DC line in real time and pre-process the original signal; A dynamic multidimensional threshold model is established based on the preprocessed original signal and the historical current signal to generate a dynamic multidimensional threshold; Combine the dynamic multi-dimensional threshold and the pre-processed original signal to calculate the overload index, divide the current overload stage, and output the current overload signal; According to the current overload signal, high-frequency oscillation detection is performed on the pre-processed original signal to obtain a high-frequency oscillation abnormal signal; According to the high-frequency oscillation abnormal signal, the DC circuit is disconnected through the fast disconnection mechanism to obtain the disconnection fault information; Perform functional self-check according to disconnection fault information and restore the disconnected DC circuit; The dynamic multi-dimensional threshold model is established based on the pre-processed original signal and the historical current signal to generate the dynamic multi-dimensional threshold. The specific steps are: A dynamic multidimensional threshold model is established based on the preprocessed original signal and historical current signal. The expression is: ； in, is a dynamic multidimensional threshold, For the current moment, is the current average value parameter, For the current moment The sliding average of the collected current signal, is the weight coefficient of the current signal fluctuation range, is the number of sampling points of the sliding window, is the sampling point index, is the time sampling point in the current time window, is the current signal collected at the time sampling point in the current time window, is the historical current trend weight coefficient, is the historical current trend integral term, is the length of the historical window, For the current moment The collected current signal, is the small time step of the time integration; The preprocessed original signal and the historical current signal are input into the dynamic multi-dimensional threshold model to calculate the dynamic multi-dimensional threshold; The method combines the dynamic multi-dimensional threshold and the pre-processed original signal to calculate the overload index, divide the current overload stage, and output the current overload signal. The specific steps are: Through the difference between the current signal in the preprocessed original signal and the dynamic multi-dimensional threshold, and introducing the dynamic adjustment factor, the overload index function is constructed to quantify the overload degree and calculate the overload index. The expression is: ； in, For the current moment The overload index, For the current moment The collected current signal, is a dynamic multidimensional threshold, is the nonlinear amplification factor of the overload index, is the dynamic adjustment factor, is the natural base, For the current moment The first derivative of the acquired current signal, is the decay rate of the rate of change to the exponential factor, For the current moment The absolute value of the first derivative of the collected current signal; Based on the value range of the overload index, the current overload stage is divided into normal operation, slight overload, moderate overload and severe overload; According to the calculated overload index and combined with the current overload stage division, a current overload signal is output.

2. The active protection method for a DC circuit breaker according to claim 1, characterized in that: The real-time acquisition of the original signal of the DC line and preprocessing of the original signal are specifically performed as follows: Collect the original signal of the DC line through current and voltage sensors; Use a digital-to-analog converter to convert the original signal from analog to digital; Use a low-pass filter to remove the high-frequency noise in the original signal; The gain of the original signal is adjusted through the gain amplifier; Use mean filtering algorithm to remove random noise from the original signal; Adjust the sensor gain and bias parameters to calibrate and calibrate the original signal; The processed original signal is transmitted to the data processing unit via the I2C bus; The original signal includes a current signal and a voltage signal.

3. The active protection method for a DC circuit breaker according to claim 2, characterized in that: According to the current overload signal, the pre-processed original signal is subjected to high-frequency oscillation detection to obtain a high-frequency oscillation abnormal signal. The specific steps are: Perform empirical mode decomposition on the current overload signal, retain the intrinsic mode function components containing high-frequency components, and extract the high-frequency component signal. The expression is: ； in, is the high frequency component signal, is the total number of modes decomposed, is the modal number index coefficient, is the first The intrinsic mode functions, For the The instantaneous frequency of an eigenmode function, is the high frequency threshold, is a Boolean indicator function; The oscillation energy is calculated based on the high-frequency component signal and normalized. The expression is: ； in, is the normalized value of high-frequency oscillation energy, is the loss power of the high frequency component signal, is the instantaneous power of the original signal after preprocessing, The length of the time window for energy calculation; The degree of high-frequency oscillation is determined based on the oscillation energy, and a high-frequency oscillation abnormality signal is output.

4. The active protection method for a DC circuit breaker according to claim 3, characterized in that: The method of disconnecting the DC circuit by a quick disconnection mechanism according to the high-frequency oscillation abnormal signal and obtaining disconnection fault information comprises the following specific steps: Determine whether a disconnection operation needs to be performed according to the high-frequency oscillation abnormal signal and the current overload signal; When it is determined that the disconnection operation is not to be performed, the standby monitoring state is entered and the original signal is continued to be monitored; When it is determined that a disconnection operation is to be performed, a disconnection instruction is sent to a drive unit of the circuit breaker, and current is cut off through an insulated gate bipolar transistor to disconnect the DC circuit; After disconnecting the DC circuit, monitor the circuit breaker working status and obtain disconnection fault information.

5. The active protection method for a DC circuit breaker according to claim 4, characterized in that: The specific steps of performing a functional self-check according to the disconnection fault information and restoring the disconnected DC circuit are as follows: According to the disconnection fault information, the sensor, switch assembly and power supply are self-checked and a self-check result report is obtained; Perform fault analysis and diagnosis based on the self-test result report, and formulate line recovery strategies according to the fault type; Execute the recovery operation according to the line recovery strategy, enter the standby monitoring state, and continue to monitor the original signal.

6. A DC circuit breaker active protection system, based on the DC circuit breaker active protection method according to any one of claims 1 to 5, characterized in that: It includes original signal acquisition module, threshold model building module, overload stage division module, high-frequency oscillation detection module, circuit quick disconnect module and fault self-detection and recovery module; The original signal acquisition module is used to collect the original signal of the DC line in real time and pre-process the original signal; The threshold model building module is used to establish a dynamic multi-dimensional threshold model based on the pre-processed original signal and the historical current signal to generate a dynamic multi-dimensional threshold; The overload stage division module is used to combine the dynamic multi-dimensional threshold and the pre-processed original signal, calculate the overload index, divide the current overload stage, and output the current overload signal; The high-frequency oscillation detection module is used to perform high-frequency oscillation detection on the pre-processed original signal according to the current overload signal to obtain a high-frequency oscillation abnormal signal; The circuit quick disconnect module is used to disconnect the DC circuit through a quick disconnect mechanism according to the high-frequency oscillation abnormal signal and obtain disconnection fault information; The fault self-checking and recovery module is used to perform a functional self-check according to the disconnection fault information and to recover and disconnect the DC circuit.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the DC circuit breaker active protection method according to any one of claims 1 to 5 are implemented.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the DC circuit breaker active protection method according to any one of claims 1 to 5 are implemented.

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