A current limiter control method, system, terminal and storage medium

Abstract

The application relates to a current limiter control method and system, a terminal and a storage medium, and relates to the technical field of current limiter control. The method comprises the following steps: acquiring a current limiter line voltage and a current limiter line current; analyzing the current limiter line voltage and the current limiter line current to determine a line actual power and a line power equivalent change amount; judging whether the line actual power and the line power equivalent change amount meet the requirements of preset normal working parameters; if yes, the current limiter line voltage and the current limiter line current are continuously acquired for cyclic judgment; if not, a preset relay is controlled to be powered off, and a tripping timestamp is acquired; the tripping timestamp and a preset tripping statistical period are analyzed to determine an automatic recovery duration; the relay is controlled to be re-attracted according to the automatic recovery duration, and the current limiter line voltage and the current limiter line current are acquired for cyclic judgment. The application has the effect of improving the accuracy of current limiter working condition discrimination.

Description

Technical Field

[0001] This application relates to the technical field of current limiter control, and in particular to a current limiter control method, system, terminal and storage medium. Background Technology

[0002] A current limiter is a protective device connected in series in a line. It can quickly limit the current in the circuit when abnormal conditions such as short circuits or frequent tripping occur. This reduces the impact damage of electric arcs generated by large currents on relay contacts and line loads, prevents equipment from overheating and burning out, and achieves graded protection in conjunction with tripping logic.

[0003] In related technologies, current limiters typically use a fixed power threshold as the sole criterion for judgment, execute on / off control via relays, and restore power supply after a fixed duration. During this process, the system often determines overload by comparing the total line power to a fixed threshold. When the monitored power exceeds the threshold, the relay is triggered to disconnect, and after a fixed recovery time, the circuit breaker is re-energized, continuing to monitor the line power to complete the full-process protection.

[0004] Regarding the aforementioned technologies, when current limiters use fixed power thresholds for judgment, they are prone to overlooking abnormal operating conditions such as instantaneous high-power load access, resulting in leakage protection problems and potentially causing electrical safety hazards such as line overheating and fires. At the same time, during the trip recovery process, the fixed-duration recovery strategy cannot distinguish between accidental misuse and malicious repeated violations, and it is difficult to adaptively adjust the penalty intensity to suppress violations, leaving room for improvement. Summary of the Invention

[0005] To improve the accuracy of current limiter condition determination, this application provides a current limiter control method, system, terminal, and storage medium.

[0006] Firstly, this application provides a current limiter control method, which adopts the following technical solution: A current limiter control method, comprising: Obtain the current limiter line voltage and current limiter line current; The voltage and current of the current limiter line are analyzed to determine the actual power and equivalent change in line power. Determine whether the actual power of the line and the equivalent change in line power meet the requirements of the preset normal operating parameters; If the conditions are met, continue to obtain the current limiter line voltage and current limiter line current for cyclical judgment; If it does not meet the requirements, the preset relay will be de-energized, and the trip timestamp will be obtained. Analyze the trip timestamp and the preset trip statistics period to determine the automatic recovery duration; The relay is controlled to re-engage based on the automatic recovery time, and the current limiter line voltage and current limiter line current are obtained for cyclic judgment.

[0007] By adopting the above technical solution, the line voltage and current are collected simultaneously to calculate the dual judgment indicators of the actual power and the power equivalent change. If either indicator is abnormal, the relay power-off protection is triggered. This can simultaneously identify two types of safety hazards: long-term overload and instantaneous high-power access, avoiding the risk of leakage protection caused by a single threshold judgment. Furthermore, by combining the trip timestamp statistics of fault frequency classification and matching the automatic recovery time, fault classification management can be achieved, and the safety of power distribution line operation can be comprehensively improved.

[0008] Optionally, the steps of analyzing the current limiter line voltage and current to determine the actual line power and the equivalent change in line power include: The active power and the original change in line power are determined based on the current limiter line voltage and current limiter line current. The original changes in line current and line power of the current limiter are analyzed to determine the equivalent change in line power. Obtain the filter cutoff frequency and power sampling frequency; The filter cutoff frequency and power sampling frequency are analyzed to determine the filter smoothing coefficient; The active power of the line and the filter smoothing coefficient are analyzed to determine the low-frequency steady-state component and the high-frequency fluctuation component. Obtain the weights of low-frequency steady-state components and high-frequency fluctuation components; The low-frequency steady-state component, high-frequency fluctuation component, weight of low-frequency steady-state component, and weight of high-frequency fluctuation component are analyzed to determine the actual power of the line.

[0009] By adopting the above technical solution, the low-frequency steady-state component and high-frequency fluctuation component of power are separated by filtering, and the actual power of the line is calculated by weighting them with corresponding weights. At the same time, the equivalent change in power is calculated separately to distinguish between steady-state overload and instantaneous power impact, thereby reducing the probability of misjudgment caused by motor starting and equipment start-up and shutdown, and improving the accuracy of power identification.

[0010] Optionally, the steps of analyzing the original changes in line current and line power of the current limiter to determine the equivalent change in line power include: The current limiter line current is analyzed to determine the effective value of the total current and the effective value of the fundamental current; The effective values ​​of the total current and the fundamental current are analyzed to determine the total harmonic distortion rate of the current. Obtain the upper limit of the weighting coefficients and the linear decay slope; The total harmonic distortion rate of the current, the upper limit of the weighting coefficient, and the linear attenuation slope are analyzed to determine the weighting coefficient for the sudden power. The original changes in line power and the weighting coefficients of sudden power changes are analyzed to determine the equivalent changes in line power.

[0011] By adopting the above technical solution, and combining the dynamic correction of the power change weighting coefficient based on the line current harmonic distortion rate, the power change judgment standard is adaptively adjusted according to the load harmonic characteristics, thereby reducing the impact of harmonic interference on instantaneous high power identification and making the equivalent power change more consistent with the actual load change conditions.

[0012] Optionally, the steps of controlling the preset relay to de-energize and obtaining the trip timestamp include: Analyze the current limiter line voltage to determine the zero-crossing time of the target voltage; Obtain the relay action delay time; The zero-crossing time of the target voltage and the relay action delay time are analyzed to determine the relay de-energization time; The trip timestamp is determined based on the time the relay is de-energized, and the relay is de-energized accordingly.

[0013] By adopting the above technical solution, the power-off command output time is calculated in advance by combining the mechanical action delay of the relay, so that the relay contacts break when the AC voltage crosses zero, which greatly suppresses the breaking arc, reduces contact erosion and loss, and extends the service life of the relay. At the same time, the trip timestamp is initially calibrated based on the voltage zero crossing time.

[0014] Optionally, the steps for determining the trip timestamp based on the relay de-energization time include: The relay coil voltage is obtained based on the moment the relay is de-energized. The relay coil voltage is analyzed to determine the rate of change of the coil voltage and the corresponding timing of the voltage change. The voltage change time is screened based on the comparison between the coil voltage change rate and the preset change rate judgment threshold in order to determine the actual contact disconnection time. The zero-crossing time of the target voltage and the actual opening time of the contacts are analyzed to determine the trip timestamp.

[0015] By adopting the above technical solution, the actual physical disconnection time of the relay coil voltage is captured, and the trip timestamp is calibrated in conjunction with the theoretical target voltage zero crossing time. This eliminates the time recording error caused by relay aging and temperature drift, ensuring high accuracy of trip timestamp recording, which facilitates subsequent fault tracing and frequency statistics.

[0016] Optionally, the steps of analyzing the trip timestamp and the preset trip statistical period to determine the automatic recovery duration include: The equivalent number of trips is determined based on the trip timestamp and the trip statistics period; Determine whether the equivalent number of trips meets the preset trip number threshold requirement; If the conditions are met, the preset first-stage duration will be set as the automatic recovery duration. If it does not meet the requirements, the preset second-stage duration will be set as the automatic recovery duration.

[0017] By adopting the above technical solution, the recovery time is divided into two levels based on the equivalent number of trips within the statistical period. For minor faults, the automatic closing time is short and the recovery interval is extended for frequent faults. This avoids repeated switching on and off of the line, which exacerbates the risk of faults, and balances power supply continuity and line safety.

[0018] Optionally, the steps for determining the equivalent number of trips based on the trip timestamp and the trip statistics period include: Analyze the trip timestamps and trip statistics periods to determine the trip interval sequence and the actual number of trips; Determine whether the trip interval sequence meets the requirements of the preset malicious probing cycle pattern; If not, the actual number of trips will be determined as the equivalent number of trips; If the conditions are met, obtain the trip weighting coefficient; The actual number of trips and the trip weighting coefficients are analyzed to determine the equivalent number of trips.

[0019] By adopting the above technical solutions, malicious power-probing behavior of short-interval anti-composite circuit breakers can be identified and a weighted coefficient can be introduced to amplify the equivalent number of trips, thereby rapidly extending the recovery time, restricting illegal power use, distinguishing between normal faults and malicious probing, and improving the adaptability of the graded recovery strategy.

[0020] Secondly, this application provides a current limiter control system, which adopts the following technical solution: A current limiter control system, comprising: The acquisition module is used to acquire the current limiter line voltage and current limiter line current; A memory for storing a program for a current limiter control method as described in any of the preceding claims; The processor and the program in the memory can be loaded and executed by the processor to implement a current limiter control method as described in any of the above.

[0021] By adopting the above technical solution, and through the operation of the intelligent terminal, the processor loads and executes a computer program of a current limiter control method stored in the memory, obtains line voltage and current parameters, and analyzes the dual indicators of steady-state power and instantaneous power change, thereby achieving accurate identification of overload and instantaneous high-power load access. Combined with voltage zero-crossing interruption, high-precision trip timestamp calibration, and graded automatic recovery strategy, it eliminates the defects of single threshold leakage protection, relay arcing, and inaccurate fault statistics, avoids the safety hazards of line overheating and fire, and thus improves the accuracy of current limiter operating condition judgment and the safety and reliability of power distribution operation.

[0022] Thirdly, this application provides a smart terminal, which adopts the following technical solution: A smart terminal includes a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executed as described in any of the preceding claims.

[0023] By adopting the above technical solution, and operating the intelligent terminal, the processor loads and executes a computer program for a current limiter control method stored in the memory. This program sequentially calculates the actual power of the line, the equivalent change in line power, the relay de-energization time, the actual contact disconnection time, and the equivalent number of trips. Then, by matching the corresponding automatic recovery time with each parameter, the circuit protection and control is completed. This takes into account the impact of long-term overload, instantaneous high-power access, relay mechanical delay, harmonic interference, and malicious power probing on line safety protection, thereby improving the accuracy of current limiter abnormal operating condition judgment and the safety of power distribution.

[0024] Fourthly, this application provides a computer storage medium capable of storing corresponding programs, which facilitates the improvement of the operational stability of the current limiter device, and adopts the following technical solution: A computer-readable storage medium storing a computer program that can be loaded by a processor and executed by any of the above-mentioned methods to improve the operational stability of a current limiter device.

[0025] By adopting the above technical solution, a computer program for a current limiter control method is stored in a computer-readable storage medium. The processor loads and executes the computer program in the storage medium, thereby sequentially calculating the actual power of the line, the equivalent change in line power, the relay de-energization time, the actual contact disconnection time, and the equivalent number of trips. Then, by combining the parameters with the corresponding automatic recovery time, the power distribution circuit protection and control is completed. This takes into account the impact of long-term overload, instantaneous high-power access, relay mechanical delay, harmonic interference, and malicious power probing on the line protection effect, thereby improving the accuracy of current limiter abnormal condition judgment and the safety of power distribution operation.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. By analyzing the line voltage and current of the current limiter, the actual power and equivalent power change of the line can be determined. Then, based on the voltage and current data, the steady-state overload index and the instantaneous power change index can be calculated respectively. This takes into account the identification of two abnormal operating conditions: long-term overload and sudden high-power access, thereby improving the accuracy of current limiter fault judgment. 2. By analyzing the trip timestamp and the preset trip statistical period, the automatic recovery time is determined. Then, the closing delay is differentiated based on the frequency of tripping within the period to distinguish between minor faults and frequent faults, avoid repeated line switching and disconnection which exacerbates safety risks, and thus improve the rationality of power distribution circuit protection and control. 3. By determining the equivalent number of trips based on the trip timestamp and trip statistics period, the system identifies short-interval malicious power consumption testing behavior and weights and corrects the number of trips, distinguishing between normal overload faults and human-caused illegal load testing, thereby improving the adaptability of graded recovery time matching. Attached Figure Description

[0027] Figure 1 This is a flowchart of a current limiter control method in an embodiment of this application.

[0028] Figure 2 This is a flowchart of the steps in this application embodiment to analyze the current limiter line voltage and current limiter line current to determine the actual line power and the equivalent change in line power.

[0029] Figure 3 This is a flowchart of the steps in this application embodiment to analyze the original changes in the current limiter line current and line power to determine the equivalent changes in line power.

[0030] Figure 4 This is a flowchart of the steps in this application embodiment to control the preset relay to power off and obtain the trip timestamp.

[0031] Figure 5 This is a flowchart of the steps for determining the trip timestamp based on the time of relay power failure in the embodiments of this application.

[0032] Figure 6 This is a flowchart of the steps in this application embodiment to analyze the trip timestamp and the preset trip statistical period to determine the automatic recovery duration.

[0033] Figure 7 This is a flowchart of the steps in this application embodiment to determine the equivalent number of trips based on the trip timestamp and the trip statistics period. Detailed Implementation

[0034] To make the purpose, technical solution, and advantages of this application clearer, the following description is provided in conjunction with the appendix. Figures 1 to 7The present application will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the application.

[0035] Reference Figure 1 This application discloses a current limiter control method, including the following steps: Step S100: Obtain the current limiter line voltage and current limiter line current; The current limiter is connected in series in the power supply line to quickly disconnect the circuit in the event of overload, short circuit or abnormal power fluctuation, so as to protect the downstream load and line safety. In order to monitor the line status and judge the protection action, an adaptive power detection and dynamic protection method is required. This protection method needs to rely on the real-time monitoring data of the current limiter line voltage and current for calculation. Therefore, it is necessary to obtain the current limiter line voltage and current.

[0036] The current limiter line voltage is the voltage between the current limiter input terminal and the output terminal or the phase voltage of the line to ground, depending on the connection method. The unit of measurement is volt (V). The detection point can be selected between the current limiter input terminal and the neutral line (or between phases). The voltage is collected by a voltage transformer at a fixed sampling frequency and then pre-stored in the processing terminal after analog-to-digital conversion.

[0037] The current limiter line current is the current of the current limiter main circuit, and the unit of measurement is ampere (A). The detection point can be selected at the copper busbar of the main circuit inlet or outlet. The current is collected by the current transformer at a sampling frequency synchronized with the voltage, and then pre-stored in the processing terminal after analog-to-digital conversion.

[0038] Step S101: Analyze the current limiter line voltage and current limiter line current to determine the actual line power and the equivalent change in line power; The actual line power is the weighted power value representing the current limiter's line power, used to determine whether the total line power exceeds the limit. The equivalent change in line power is the weighted change in the current limiter's line power, used to determine whether any appliances exceeding the power limit are being used. The actual line power and the equivalent change in line power are obtained through analysis of the current limiter's line voltage and current; the specific method is described in [reference needed]. Figure 2 The steps.

[0039] Step S102: Determine whether the actual power of the line and the equivalent change in line power meet the requirements of the preset normal operating parameters; The normal operating parameters are critical threshold standards used to determine whether the line load is within the safe operating range, including the line rated power and the rated power variation. The line rated power is the maximum power of the line during normal operation. It is obtained by continuously and stably operating the load under standard conditions, calculating the power value cycle by cycle according to the power frequency period, continuously collecting no less than 100 sets of data, removing outliers, and averaging the values. This average value is then pre-stored in the processing terminal; in this embodiment, it is set to 2800W. The rated power variation is the maximum allowable power fluctuation amplitude between adjacent power frequency cycles. It is obtained by operating the load within the allowable maximum normal dynamic adjustment process, synchronously collecting and calculating the power value for each power frequency cycle, sequentially calculating the absolute value of the power difference between adjacent cycles, and recording the maximum value among all differences. This value is the rated power variation; in this embodiment, it is 400W or 600W. The requirement for normal operating parameters is that the duration exceeding the normal operating parameters does not exceed the preset over-limit duration.

[0040] The over-limit duration is the duration during which the actual power of the line exceeds the rated power of the line and the duration during which the equivalent change in line power exceeds the rated change in line power. It is set by the operator. In this embodiment, the over-limit durations are 2 seconds and 2.5 seconds, respectively.

[0041] Relying on a single power threshold can only identify long-term overloads and cannot capture the potential power surge caused by instantaneous high-power load access. By comparing the actual power of the line and the equivalent change in line power with the corresponding rated power and rated change in line power within the normal operating parameters, two dangerous operating conditions can be identified simultaneously: continuous overload and instantaneous high-power impact. If the actual power of the line is greater than the rated power for more than 2 seconds or the equivalent change in line power is greater than the rated change in line power for more than 2.5 seconds, it indicates that the line is in a long-term overload or abnormal impact state. The continuous heat accumulation will accelerate the aging of the line insulation layer and even reach the ignition point, thus determining that the line has an overheating and fire risk and executing power outage protection. This eliminates the leakage protection defects of a single judgment standard and comprehensively improves the power safety protection capability of the distribution circuit.

[0042] Step S1021: If the condition is met, continue to obtain the current limiter line voltage and current limiter line current for cyclic judgment; If the actual power of the line exceeds the rated power of the line for no more than 2 seconds and the equivalent change in line power exceeds the rated change in line power for no more than 2.5 seconds, it indicates that the total power has not exceeded the limit and no high-power electrical appliances are being used, and there is no safety risk to the line. At this time, the voltage and current of the current limiter line can be collected to continuously monitor the power consumption of the current limiter circuit.

[0043] Step S1022: If the condition is not met, the preset relay is de-energized and the trip timestamp is obtained; If the actual power of the line exceeds the rated power for more than 2 seconds, or the equivalent change in line power exceeds the rated change for more than 2.5 seconds, it indicates that the total power in the line is over-limit or that high-power appliances are being used, posing a potential electrical safety hazard. To protect user safety and prevent the fault from escalating, it is necessary to control the relay to cut off the power and record the trip timestamp. For specific methods, refer to [reference needed]. Figure 4 The steps.

[0044] A relay is an electromagnetic or solid-state switching element built into a current limiter. When its coil is energized, the contacts close and the circuit is connected; when the coil is de-energized, the contacts open and the circuit is disconnected.

[0045] The trip timestamp is the specific moment corresponding to this power outage action, which is used for subsequent statistics on the number of trips and calculation of automatic recovery time.

[0046] Step S103: Analyze the trip timestamp and the preset trip statistical period to determine the automatic recovery duration; The tripping statistics period is a pre-set time window length used to count the number of trips that occur within the window to determine the frequency of the fault. When the fault occurs frequently, the automatic recovery time is increased. The tripping statistics period is set by the operator according to the importance of the line and the load characteristics. In this embodiment, the tripping statistics period is set to 24 hours.

[0047] The automatic recovery time is the waiting time required for the system to automatically attempt to close the circuit breaker after the relay is de-energized. The automatic recovery time is set by the operator; in this embodiment, it is 15 seconds or 5 minutes. The automatic recovery time is obtained by analyzing the trip timestamp and a preset trip statistical period; the specific method is described in [reference needed]. Figure 6 The steps.

[0048] Step S104: Control the relay to re-engage according to the automatic recovery time, and obtain the current limiter line voltage and current limiter line current for cyclic judgment.

[0049] After the automatic recovery timer completes, the processor outputs a closing drive signal to activate the relay, restoring power to the line. After reactivation, the line may have returned to normal, or the fault may still exist. Therefore, it is necessary to continue acquiring the voltage and current of the current limiter line for cyclical judgment.

[0050] Reference Figure 2 The steps for analyzing the current limiter line voltage and current to determine the actual line power and the equivalent change in line power include: Step S200: Determine the active power and the original change in line power based on the current limiter line voltage and current limiter line current; The line active power is the effective electrical energy consumed continuously by the load. It is obtained by multiplying the line voltage and current of the current limiter point by point within one cycle, adding them together, and then dividing by the number of sampling points in that cycle. The original change in line power is the amplitude of power fluctuation between adjacent cycles. It is obtained by subtracting the line active power of the current cycle from the line active power of the previous cycle and taking the absolute value.

[0051] Step S201: Analyze the original changes in line current and line power of the current limiter to determine the equivalent change in line power; The equivalent change in line power in this step is consistent with the equivalent change in line power in step S101, and is obtained by analyzing the original changes in line current and line power of the current limiter. The specific method is described in [reference needed]. Figure 3 The steps.

[0052] Step S202: Obtain the filter cutoff frequency and power sampling frequency; The filter cutoff frequency is the highest frequency component that the digital low-pass filter allows to pass, measured in Hertz (Hz). It defines the frequency band from which trend components can be extracted from the active power of the line. The filter cutoff frequency is set by the operator based on the dynamic response characteristics of the load and the grid frequency, and is typically set to 1 / 10 of the active power of the line. 2 / 5 (i.e., 5Hz to 20Hz) to preserve the slow variation trend and filter out high-frequency noise.

[0053] The power sampling frequency is the rate at which the processing terminal samples the active power of the line, and the unit of measurement is Hertz (Hz). This frequency is consistent with or a division of the sampling frequency of the current limiter line voltage and current. It must satisfy the Nyquist sampling theorem to ensure that the signal is not distorted. It is determined by the operator and then pre-stored in the processing terminal.

[0054] Step S203: Analyze the filter cutoff frequency and power sampling frequency to determine the filter smoothing coefficient; The smoothing coefficient is a key parameter of the low-pass filter, used to control the filter's response speed and smoothness. Its value ranges between 0 and 1; a value closer to 1 results in stronger smoothing but slower response, while a value closer to 0 results in faster response but poorer smoothness. (The formula is used to...) The calculation yields the following result: The filtering smoothing coefficient is... This is the filter cutoff frequency. This is the power sampling frequency.

[0055] This is the cutoff angular frequency of the low-pass filter, representing the natural angular velocity of the low-frequency signals that the filtering stage itself allows to pass. The larger the value, the higher the upper limit of the frequency allowed by the filter, and the weaker the smoothing and weakening effect of the filter. It integrates two types of constraints: the discrete acquisition rate at the sampling end and the cutoff characteristics of the filter itself. Dividing the two is essentially to find the proportion of the cutoff feature in the overall feature scale, which yields the filter smoothing coefficient.

[0056] Step S204: Analyze the line active power and filter smoothing coefficient to determine the low-frequency steady-state component and high-frequency fluctuation component; Among them, the low-frequency steady-state component is a slowly changing trend component in the power signal, reflecting the average power consumption level of the load, and is measured in watts (W). This is expressed by the formula... The calculation yields the following result: It is a low-frequency steady-state component. The filtering smoothing coefficient is used to smooth the active power of the line through recursive calculation, filtering out high-frequency fluctuation components and retaining long-term steady-state components.

[0057] High-frequency fluctuation components represent rapidly changing transient components in the power signal, reflecting the impact, noise, or disturbance of the load, and are measured in watts (W). They are obtained by subtracting the low-frequency steady-state component from the line's active power.

[0058] Step S205: Obtain the weights of the low-frequency steady-state component and the high-frequency fluctuation component; The weight of the low-frequency steady-state component is a proportional coefficient assigned to the low-frequency steady-state component when calculating the actual power of the line. The value range is usually 0.5 to 0.9, and it is set by the operator according to the load inertia.

[0059] The weight of the high-frequency fluctuation component is a proportional coefficient assigned to the high-frequency fluctuation component, which is also set by the operator, and the sum of the weight of the low-frequency steady-state component and the weight of the high-frequency fluctuation component is 1.

[0060] The weights of the low-frequency steady-state component and the high-frequency fluctuation component reflect the importance attached to steady-state power consumption and transient disturbances when evaluating the actual power of the line. For motor-type loads with stable power consumption, the weight of the low-frequency steady-state component can be increased, while for electronic devices with frequent power fluctuations, the weight of the high-frequency fluctuation component can be appropriately increased to adapt to different load characteristics and reduce misjudgments.

[0061] Step S206: Analyze the low-frequency steady-state component, the high-frequency fluctuation component, the weight of the low-frequency steady-state component, and the weight of the high-frequency fluctuation component to determine the actual power of the line.

[0062] In this step, the actual power of the line is consistent with that in step S101. It is obtained by multiplying the low-frequency steady-state component by the weight of the low-frequency steady-state component and adding the high-frequency fluctuation component by the weight of the high-frequency fluctuation component. This value combines stable power consumption and dynamic impact, and can more accurately reflect the true load state of the line than the line active power alone.

[0063] Reference Figure 3 The steps for analyzing the original changes in line current and line power of the current limiter to determine the equivalent change in line power include: Step S300: Analyze the current in the current limiter circuit to determine the effective value of the total current and the effective value of the fundamental current; The total current RMS value is a fundamental quantity characterizing the overall magnitude of the current in the current limiter's line, measured in amperes (A). It is obtained by calculating the root mean square (RMS) of the current in the current limiter's line current over one cycle. The fundamental current RMS value is the RMS value of the component of the current whose frequency equals the power frequency (50Hz or 60Hz), also measured in amperes (A). The processing terminal performs a Fast Fourier Transform (FFT) on the current limiter's line current over a single cycle to extract the sine and cosine components corresponding to the power frequency fundamental. The two components are squared separately, summed, and the square root of the sum is divided by the number of sampling points in a single cycle to obtain the fundamental current RMS value.

[0064] Step S301: Analyze the RMS value of the total current and the RMS value of the fundamental current to determine the total harmonic distortion rate of the current; The total harmonic distortion (THD) rate of current characterizes the severity of current waveform distortion and is an important indicator for measuring power quality. This is achieved through the formula... The calculation yields the following result: The total harmonic distortion of the current. This is the effective value of the total current. This represents the effective value of the fundamental current.

[0065] The current waveform of purely resistive prohibited loads (such as immersion heaters and electric furnaces) is close to a standard sine wave and contains almost no high-order harmonics. The values ​​are very small; the current waveforms of compliant loads such as computers and chargers, which are switching power supplies, are severely distorted and contain a large number of high-order harmonics. The value is large.

[0066] Step S302: Obtain the upper limit of the weighting coefficients and the linear decay slope; The upper limit of the weighting coefficient is the maximum value of the sudden power weighting coefficient when the total harmonic distortion of the current is zero. It is typically set to 1 or slightly greater than 1. It is set to 1 when there is little interference and weak power fluctuations. The stronger the electromagnetic interference and load power impact, the larger the value should be. The normal range is 1. 1.5 After on-site calibration by the operator, the data is pre-stored in the processing terminal.

[0067] The linear attenuation slope is the rate of change of the sudden power weighting coefficient as the total harmonic distortion rate of the current increases, meaning that for every unit increase in power weighting coefficient, the linear decrease in power weighting coefficient is achieved. The decrease in the power weighting coefficient for each 10% change is determined by the amount of harmonic content at the site. The higher the harmonic content and the more obvious the interference of harmonics on power sampling, the larger the absolute value of the linear attenuation slope. The operator adjusts the linear attenuation slope step by step and observes the power calculation error. The linear attenuation slope with the smallest error is selected and pre-stored in the processing terminal.

[0068] Step S303: Analyze the total harmonic distortion rate of the current, the upper limit of the weighting coefficient, and the linear attenuation slope to determine the weighting coefficient for the sudden power. The sudden power weighting coefficient is a factor used to correct the original change in line power. It is obtained by subtracting the product of the total harmonic distortion rate of the current and the linear attenuation slope from the upper limit of the weighting coefficient. When the total harmonic distortion rate of the current is severe, high-frequency noise accounts for a large proportion of the original change in line power, and its weight should be reduced to avoid misjudgment. When the total harmonic distortion rate of the current is slight, the original change in line power truly reflects the load change, and its weight should be retained to a larger extent.

[0069] Step S304: Analyze the original change in line power and the weighting coefficient of sudden power change to determine the equivalent change in line power.

[0070] In this step, the equivalent change in line power is the same as that in step S101, and is obtained by multiplying the original change in line power by the weighting coefficient of the sudden power change.

[0071] Reference Figure 4 The steps for controlling the preset relay to cut off power and obtaining the trip timestamp include: Step S400: Analyze the current limiter line voltage to determine the zero-crossing time of the target voltage; The target voltage zero-crossing moment is the moment when the line voltage waveform changes from positive to negative or from negative to positive and crosses zero. In this context, it represents the predicted next voltage zero-crossing moment. At the target voltage zero-crossing moment, the voltage difference across the relay contacts is minimal, and the arc energy is lowest during disconnection, making it the optimal time for the relay to open. The current limiter line voltage is sampled. When two consecutive sampling points are detected with opposite voltage signs, the corresponding time and voltage values ​​are obtained, which are respectively the sampling time before zero-crossing, the sampling time after zero-crossing, the sampling voltage before zero-crossing, and the sampling voltage after zero-crossing. The current voltage zero-crossing moment is calculated using a preset linear interpolation formula. Finally, the power frequency period is added to the current voltage zero-crossing moment to obtain the target voltage zero-crossing moment.

[0072] The linear interpolation formula is: .

[0073] In the formula, At the current voltage zero-crossing moment, For the time before the zero crossing sampling point, The voltage at the sampling point before zero crossing. The voltage at the sampling point after zero crossing. The sampling point time is after the zero crossing.

[0074] This indicates the proportion of the voltage range occupied by the zero potential point. The time span between the two samplings and Multiplying these two times gives the time elapsed from the sampling point before the zero-crossing to the zero-crossing time of the target voltage. Adding this time to the sampling point before the zero-crossing gives the zero-crossing time of the target voltage.

[0075] Step S401: Obtain the relay action delay time; The relay action delay time is the total delay required from the time the power-off command is issued by the processing terminal to the actual physical disconnection of the relay contacts. It is obtained by the operator by consulting the relay's factory specifications and is pre-stored in the processing terminal.

[0076] Step S402: Analyze the zero-crossing moment of the target voltage and the relay action delay time to determine the relay de-energization moment; The relay de-energization time is the specific time when the processing terminal should issue a de-energization command to the relay coil. To ensure that the actual contact disconnection time is as close as possible to the target voltage zero crossing time, the de-energization command should be issued earlier than the target voltage zero crossing time. The advance amount is equal to the relay action delay time. Therefore, the relay de-energization time is obtained by subtracting the relay action delay time from the target voltage zero crossing time.

[0077] Step S403: Determine the trip timestamp based on the time the relay is de-energized, and control the relay to de-energize.

[0078] The processing terminal outputs a power-off signal at the moment the relay is de-energized, and simultaneously starts a timer to record this moment as the initial reference point for the trip timestamp. The command issuance time is not the actual physical moment the line is disconnected; therefore, further analysis is needed to calibrate and determine the trip timestamp. Specific methods are detailed below. Figure 5 The steps.

[0079] Reference Figure 5 The steps for determining the trip timestamp based on the relay de-energization time include: Step S500: Obtain the relay coil voltage based on the moment the relay is de-energized; When the relay contacts physically disconnect, the voltage across the drive coil will change sharply. Therefore, by collecting the relay coil voltage, the actual physical disconnection time of the contacts can be captured, and the tripping timestamp error caused by the zero-crossing moment of the target can be corrected.

[0080] The relay coil voltage is the real-time control voltage across the relay drive coil, measured in volts (V). The detection point can be selected from the control circuit across the low-voltage drive coil of the relay. A resistor divider network is used to attenuate the coil voltage to the input range that the analog-to-digital converter (ADC) can withstand. After electrical isolation is achieved through an optocoupler or isolation amplifier, the voltage is sampled and measured by the ADC module built into the processing terminal.

[0081] Step S501: Analyze the relay coil voltage to determine the coil voltage change rate and the corresponding voltage change time; Among them, the coil voltage change rate is a value that characterizes the magnitude of voltage change. By performing high-frequency discrete sampling of the relay coil voltage, taking the voltage difference between adjacent sampling times and dividing it by the sampling interval, the calculation is completed by approximating the differential with difference, quantifying the rate of change of coil voltage over time, thereby capturing instantaneous voltage change at the coil end, which is used to predict the magnetic attraction state of the relay, check for abnormal disturbances in the coil, and optimize the switching action control effect.

[0082] The voltage change moment is the point in time at which the amplitude of the coil voltage changes. The sampling time is recorded simultaneously with the rate of change of the coil voltage, and this time is defined as the voltage change moment.

[0083] Step S502: Based on the comparison between the coil voltage change rate and the preset change rate judgment threshold, the voltage change time is screened to determine the actual contact disconnection time; The rate of change threshold is a critical value for the coil voltage change rate, used to determine whether the relay will complete its disconnection action. By repeatedly testing the relay under normal operating conditions, the large voltage change rate caused by contact disconnection is distinguished from the small change rate caused by noise and minor disturbances in the power grid. The median value between these two ranges is selected as the initial rate of change threshold. Then, based on the degree of temperature drift, the strength of electromagnetic interference, and the characteristics of line harmonics, the parameters are fine-tuned to finally determine the rate of change threshold adapted to the actual operating conditions.

[0084] The actual moment the contacts open is the true time when the relay contacts physically separate and the circuit is completely de-energized. By comparing the coil voltage change rate at each sampling point with the change rate judgment threshold, coil voltage change rates lower than the change rate judgment threshold are eliminated, and the voltage change time corresponding to the retained coil voltage change rate is the actual moment the contacts open.

[0085] When the rate of change of the coil voltage is greater than the rate of change judgment threshold, it means that there is a sufficiently significant sudden change in the coil voltage, indicating that the relay contacts are about to complete the disconnection action; if the rate of change of the coil voltage is not greater than the rate of change judgment threshold, the corresponding voltage fluctuation is only a small sampling noise or a minor daily disturbance, and the relevant voltage changes need to be screened out at all times to avoid misjudgment.

[0086] Step S503: Analyze the zero-crossing time of the target voltage and the actual disconnection time of the contacts to determine the trip timestamp.

[0087] In this step, the trip timestamp is consistent with the trip timestamp in step S1022. Based on the actual disconnection time of the contact, and combined with the zero-crossing time of the target voltage before and after, the timing offset of the contact disconnection time relative to the zero point of the power frequency voltage is calculated. The actual disconnection time of the contact, which includes the offset phase information and the complete time coordinate, is uniformly marked as the trip timestamp, which is used to completely retain the accurate timing information of the trip event.

[0088] The actual contact disconnection time is only a simple absolute time, lacking power frequency phase information. By using the voltage zero-crossing moment as a unified phase reference for the power frequency waveform, the timing offset of the tripping action relative to the voltage zero point can be calculated. This allows the tripping timestamp to simultaneously contain precise time and waveform phase information. On the one hand, it can verify the actual deviation of the relay's zero-crossing disconnection, which can be used to dynamically optimize the drive delay and suppress contact arcing. On the other hand, it unifies the timing standard of the entire process, ensuring the interoperability of timing data between steps, and also facilitates the rapid location of the waveform phase corresponding to the tripping during subsequent fault recording and harmonic analysis, enabling accurate fault tracing.

[0089] Reference Figure 6 The steps for analyzing trip timestamps and preset trip statistical periods to determine the automatic recovery duration include: Step S600: Determine the equivalent number of trips based on the trip timestamp and trip statistics period; The equivalent trip count, a weighted adjusted number of trips, is used to measure the frequency of line faults. It is determined based on the trip timestamp and the trip statistics period; specific methods are detailed in [reference needed]. Figure 7 The steps.

[0090] Step S601: Determine whether the equivalent number of trips meets the preset trip number threshold requirement; The tripping frequency threshold is a critical value used to distinguish between transient disturbances and persistent faults. It is set by the operator based on the importance of the line and the equipment's tolerance, and pre-stored in the processing terminal; in this embodiment, it is 20 tripping times. The tripping frequency threshold must not exceed the specified threshold value.

[0091] The equivalent number of trips comprehensively reflects the frequency of recent line faults. If the number is low, it indicates that the tripping event is an occasional, instantaneous disturbance. In this case, a shorter time is used to quickly restore power supply, which can minimize the impact of the outage. If the equivalent number of trips exceeds the threshold, it indicates that there is a recurring anomaly in the line. In this case, a longer time is used to restore power supply, which can suppress repeated violations and also avoid secondary impacts on equipment and lines caused by repeated reclosing.

[0092] Step S6011: If the conditions are met, the preset first-stage duration is determined as the automatic recovery duration; If the equivalent number of trips is not greater than the trip number threshold, it means that the trip frequency is low within 24 hours, which is only an occasional instantaneous disturbance and belongs to a minor fault condition. Therefore, the preset first-order short-term automatic recovery time is selected to achieve rapid power restoration after the fault and reduce the power outage time and power supply loss.

[0093] The first-stage duration is a shorter automatic recovery waiting time used when the equivalent number of trips does not exceed the trip count threshold, for rapid power restoration after occasional disturbances. It is set and pre-stored in the processing terminal by the operator based on load characteristics and grid fluctuations; in this embodiment, it is set to 15 seconds.

[0094] Step S6012: If it does not meet the requirements, the preset second-stage duration will be set as the automatic recovery duration.

[0095] If the equivalent number of trips is greater than the trip number threshold, it means that the trip frequency is high within 24 hours and the line has a continuous and repeated anomaly. Therefore, the second-order long-term automatic recovery time is selected to extend the closing waiting time, suppress the repeated tripping behavior of the line, and reduce the secondary impact on the line and equipment caused by multiple reclosing.

[0096] The second-stage duration is a longer automatic recovery waiting time used when the equivalent number of trips exceeds the tripping threshold. It is used for delayed power restoration after frequent faults. This timeframe is set by the operator based on line tolerance and equipment protection requirements and pre-stored in the processing terminal; in this embodiment, it is set to 5 minutes.

[0097] Reference Figure 7 The steps for determining the equivalent number of trips based on the trip timestamp and trip statistics period include: Step S700: Analyze the trip timestamp and trip statistical period to determine the trip interval sequence and the actual number of trips; The trip interval sequence is an ordered sequence of time intervals between two consecutive trips within the statistical period. It visually reflects the frequency of trips and helps determine whether a fault is sporadic or continuous. The actual trip count is the total number of trip events that occurred within the statistical period. By retrieving all trip timestamps recorded within the statistical period, arranging them in ascending order of occurrence, and calculating the time difference between adjacent timestamps, all differences are combined to form the trip interval sequence. The total number of trip timestamps within the statistical period is then counted to obtain the actual trip count.

[0098] Step S701: Determine whether the tripping interval sequence meets the requirements of the preset malicious probing cycle pattern; The malicious probing cycle pattern is a pre-entered standard of fixed time intervals for processing terminals, used to identify malicious behavior such as periodic and frequent tripping. It can be obtained by maintenance personnel through repeated load switching probing operations, recording the fixed timing characteristics exhibited during these operations. The requirement for the malicious probing cycle pattern is that it be basically consistent with the actual malicious probing cycle pattern.

[0099] Because malicious human probing of the line will produce a stable and periodically repeating trip sequence, while the trip intervals caused by random disturbances and instantaneous faults in the power grid are chaotic and have no fixed period, there is a clear distinction between the timing characteristics of the two. Therefore, this characteristic can be used to achieve differentiated identification and protection between faults and malicious operations.

[0100] Step S7011: If it does not meet the requirements, then the actual number of trips will be determined as the equivalent number of trips; If the tripping interval sequence is inconsistent with the malicious probing cycle pattern, it indicates that the tripping is caused by random disturbances or occasional faults in the power grid, and there is no human-induced periodic probing operation. The actual number of trips can be directly determined as the equivalent number of trips.

[0101] Step S7012: If the conditions are met, obtain the trip weighting coefficient; If the trip interval sequence is basically consistent with the malicious probing cycle, it indicates that the frequent tripping is a deliberate periodic malicious probing behavior. Such repeated switching will continuously generate electric arcs and aggravate contact losses. Instead of directly using the actual number of trips to count the losses, it is necessary to retrieve the trip weighting coefficient to amplify the loss conversion value of a single trip, so as to accurately reflect the serious equipment damage caused by malicious probing.

[0102] The trip weighting factor is an amplified conversion parameter for scenarios of malicious human probing. The value is greater than 1. It is used to aggravate the loss conversion of trips caused by malicious probing. It is set by the operator in combination with the line equipment's tolerance capacity and is pre-stored in the processing terminal.

[0103] Step S702: Analyze the actual number of trips and the trip weighting coefficient to determine the equivalent number of trips.

[0104] In this step, the equivalent number of trips is the same as the equivalent number of trips in step S600. The equivalent number of trips is obtained by multiplying the actual number of trips by the trip weighting coefficient.

[0105] Based on the same inventive concept, embodiments of this application provide a current limiter control method, including: The acquisition module is used to acquire the current limiter line voltage, current limiter line current, filter cutoff frequency, power sampling frequency, low-frequency steady-state component weight, high-frequency fluctuation component weight, upper limit of weighting coefficient, linear attenuation slope, relay action delay time and trip weighting coefficient. A memory used to store a program for a current limiter control method; The processor can load and execute programs in memory to implement a current limiter control method.

[0106] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0107] This application provides a computer-readable storage medium storing a computer program that can be loaded by a processor and executed as a current limiter control method.

[0108] Computer storage media include, for example, USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, optical disks, and other media that can store program code.

[0109] Based on the same inventive concept, embodiments of this application provide a smart terminal, including a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executed as a current limiter control method.

[0110] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0111] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Any feature disclosed in this specification (including the abstract and drawings) may be replaced by other equivalent or similar features unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is only one example of a series of equivalent or similar features.

Claims

1. A current limiter control method, characterized in that, include: Obtain the current limiter line voltage and current limiter line current; The voltage and current of the current limiter line are analyzed to determine the actual power and equivalent change in line power. Determine whether the actual power of the line and the equivalent change in line power meet the requirements of the preset normal operating parameters; If the conditions are met, continue to obtain the current limiter line voltage and current limiter line current for cyclical judgment; If it does not meet the requirements, the preset relay will be de-energized, and the trip timestamp will be obtained. Analyze the trip timestamp and the preset trip statistics period to determine the automatic recovery duration; The relay is controlled to re-engage based on the automatic recovery time, and the current limiter line voltage and current limiter line current are obtained for cyclic judgment.

2. The current limiter control method according to claim 1, characterized in that, The steps for analyzing the current limiter line voltage and current to determine the actual line power and the equivalent change in line power include: The active power and the original change in line power are determined based on the current limiter line voltage and current limiter line current. The original changes in line current and line power of the current limiter are analyzed to determine the equivalent change in line power. Obtain the filter cutoff frequency and power sampling frequency; The filter cutoff frequency and power sampling frequency are analyzed to determine the filter smoothing coefficient; The active power of the line and the filter smoothing coefficient are analyzed to determine the low-frequency steady-state component and the high-frequency fluctuation component. Obtain the weights of low-frequency steady-state components and high-frequency fluctuation components; The low-frequency steady-state component, high-frequency fluctuation component, weight of low-frequency steady-state component, and weight of high-frequency fluctuation component are analyzed to determine the actual power of the line.

3. The current limiter control method according to claim 2, characterized in that, The steps for analyzing the original changes in line current and line power of the current limiter to determine the equivalent change in line power include: The current limiter line current is analyzed to determine the effective value of the total current and the effective value of the fundamental current; The effective values ​​of the total current and the fundamental current are analyzed to determine the total harmonic distortion rate of the current. Obtain the upper limit of the weighting coefficients and the linear decay slope; The total harmonic distortion rate of the current, the upper limit of the weighting coefficient, and the linear attenuation slope are analyzed to determine the weighting coefficient for the sudden power. The original changes in line power and the weighting coefficients of sudden power changes are analyzed to determine the equivalent changes in line power.

4. The current limiter control method according to claim 1, characterized in that, The steps for controlling the preset relay to disconnect from power and obtaining the trip timestamp include: Analyze the current limiter line voltage to determine the zero-crossing time of the target voltage; Obtain the relay action delay time; The zero-crossing time of the target voltage and the relay action delay time are analyzed to determine the relay de-energization time; The trip timestamp is determined based on the time the relay is de-energized, and the relay is de-energized accordingly.

5. A current limiter control method according to claim 4, characterized in that, The steps for determining the trip timestamp based on the relay de-energization time include: The relay coil voltage is obtained based on the moment the relay is de-energized. The relay coil voltage is analyzed to determine the rate of change of the coil voltage and the corresponding timing of the voltage change. The voltage change time is screened based on the comparison between the coil voltage change rate and the preset change rate judgment threshold in order to determine the actual contact disconnection time. The zero-crossing time of the target voltage and the actual opening time of the contacts are analyzed to determine the trip timestamp.

6. The current limiter control method according to claim 1, characterized in that, The steps for analyzing trip timestamps and preset trip statistics periods to determine the automatic recovery duration include: The equivalent number of trips is determined based on the trip timestamp and the trip statistics period; Determine whether the equivalent number of trips meets the preset trip number threshold requirement; If the conditions are met, the preset first-stage duration will be set as the automatic recovery duration. If it does not meet the requirements, the preset second-stage duration will be set as the automatic recovery duration.

7. A current limiter control method according to claim 6, characterized in that, The steps for determining the equivalent number of trips based on the trip timestamp and trip statistics period include: Analyze the trip timestamps and trip statistics periods to determine the trip interval sequence and the actual number of trips; Determine whether the trip interval sequence meets the requirements of the preset malicious probing cycle pattern; If not, the actual number of trips will be determined as the equivalent number of trips; If the conditions are met, obtain the trip weighting coefficient; The actual number of trips and the trip weighting coefficients are analyzed to determine the equivalent number of trips.

8. A current limiter control system, characterized in that, include: The acquisition module is used to acquire the current limiter line voltage and current limiter line current; A memory for storing a program of a current limiter control method as described in any one of claims 1 to 7; The processor and the program in the memory can be loaded and executed by the processor to implement the current limiter control method as described in any one of claims 1 to 7.

9. A smart terminal, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and executed as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer program is stored and can be loaded by a processor and executed as described in any one of claims 1 to 7.

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