Automatic recloser multi-segment definite-time-limit over-current control method and recloser thereof

Abstract

The invention relates to the technical field of power distribution networks, in particular to an automatic recloser multi-section definite-time-limit overcurrent control method and a recloser thereof, comprising a control cabinet, the control cabinet is internally provided with a controller for bearing an instantaneous reaction module, a data collection module, a feature extraction module, a similarity matching module and a historical database, and parameters in a circuit are monitored in real time, so as to realize the multi-section definite-time-limit overcurrent control of the recloser. When an abnormality occurs, calculating and analyzing the corresponding parameters, judging the similarity between the parameters and historical data, further judging the general type of the fault, and performing a corresponding switching-on action according to the judged fault type; through the combination of instantaneous reaction and intelligent judgment and switching on, instantaneous faults can be solved as soon as possible, or switching on operation is no longer tried too much for permanent faults, loss is reduced, and corresponding data are stored after the current fault type is confirmed, so that subsequent comparison is facilitated.

Description

Technical Field

[0001] This invention relates to the field of recloser technology, specifically to a multi-segment time-limited overcurrent control method for automatic reclosers and the recloser thereof. Background Technology

[0002] A recloser, generally speaking, refers to a circuit breaker equipped with reclosing capability. This means it provides circuit protection and can quickly trip and reclose after a sudden, transient fault to ensure continuous power transmission. Typical reclosers use a three-stage overcurrent protection method: the first stage directly trips if the current is too high; the second stage trips after a timed delay; and the third stage trips after a longer timed delay to handle transient faults in the circuit. After three trips, the circuit is completely locked. However, this type of recloser can only detect the current magnitude in real time and then mechanically perform actions such as opening and closing. For some transient faults that may take longer to clear up naturally, it may cause the circuit breaker to lock up. That is, the recloser can react to the magnitude of the instantaneous current in a timely manner, but it cannot provide targeted feedback on what type of fault this abnormality may be, which limits the effectiveness of the recloser.

[0003] Therefore, a multi-segment time-limit overcurrent control method for automatic reclosers and its reclosers are needed to solve the problem that reclosers cannot make more accurate judgments for different faults. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a multi-segment time-limit overcurrent control method for automatic reclosers and a recloser thereof. By detecting current and voltage parameters in the circuit, analyzing and processing them, other characteristic parameters are obtained, and compared with historical data to determine the fault type. Then, targeted processing is performed to resolve the fault problem as quickly as possible.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution: the automatic recloser multi-segment time-limited overcurrent control method and the recloser thereof, including S1, in the process of the recloser monitoring the circuit state, real-time acquisition of circuit parameters and switching parameters, and respectively transmitting the corresponding parameters to the time-limited data storage library in the instantaneous response module and the data collection module. S2, the instantaneous response module compares the instantaneous value of the three-phase current in the circuit with the set current value. When a data abnormality occurs, it will continuously initiate two actions of opening and closing the circuit breaker. There are three intervals where the data abnormality exists and three opening and closing methods are adopted, namely: immediate execution, execution after a delay according to the first set time, and execution after a delay according to the second set time. S3, when the circuit parameter data is abnormal, a signal with a timestamp is sent to the data collection module. The data collection module then retrieves all previous data and some future data within the time window centered on the timestamp from the time-limited data storage library and sends it to the feature extraction module. After receiving the fault data packet, the feature extraction module calculates the transient characteristics, steady state and harmonic characteristic parameters, extracts the features, and forms a fault data feature packet. S4, transmit the extracted data to the similarity matching module and perform similarity judgment with the data in the historical database, and mark the data packet after the current data feature extraction as permanent fault, transient fault, or fault of undetermined type; S5, for permanent faults, the circuit will be closed a maximum of two times; for transient faults and faults whose type cannot be determined, the circuit will be closed a maximum of five times and three times respectively, and a different interval time will be set for each closing. If the fault is not resolved after reaching the maximum number of closing times, the circuit will be locked in the open state and wait for maintenance personnel. The process will end when the fault is resolved. The final type of the aforementioned fault is synchronously fed back to the historical database.

[0006] The present invention is further configured such that: the circuit parameters in S1 include the instantaneous values ​​of the three-phase current and the three-phase voltage in the circuit, and the switching parameters include the switch position state and the switch energy storage state. All data parameters are packaged and transmitted to the data collection module and timestamped, and then stored in the time-limited data storage library. The data of the instantaneous values ​​of the three-phase current, the switch position state, and the switch energy storage state in the circuit are transmitted to the instantaneous response module.

[0007] The present invention is further configured such that: Ia, Ib, and Ic of the three-phase currents are respectively related to a set current value Ia 设 Ib 设 Ic 设 The system compares the three-phase currents and takes action when any one of the three-phase currents, Ia, Ib, or Ic, meets the conditions. The three-phase currents are compared synchronously with three set current values. Different reaction speeds are used to delay the opening and closing actions when different set current values ​​are met. When multiple set adjustments are met in a short period of time, the action with the shorter delay is preferred.

[0008] The present invention is further configured such that: the instantaneous response module is also provided with a status toggle signal plate, which synchronously sends a signal with a timestamp to the data collection module when the instantaneous response module detects abnormal data and performs opening or closing actions.

[0009] The present invention is further configured such that: the feature extraction module calculates the following based on the corresponding parameter data: current mutation amount, current mutation rate, current waveform parameters, fundamental effective value, negative sequence current, zero sequence current, and total harmonic distortion rate, and forms multiple feature parameters into a fault data feature package.

[0010] The present invention is further configured such that: for similarity determination, data preprocessing is required first, then the similarity of the two dimensions is calculated using both Euclidean distance similarity and cosine similarity calculation methods, and finally the final similarity is obtained. Final similarity = 0.4 Euclidean distance similarity + 0.6 cosine similarity.

[0011] The present invention is further configured such that: a recloser includes a circuit breaker body and a control cabinet; The circuit breaker body performs current opening and closing actions when receiving signals. The circuit breaker body is also equipped with detectors for detecting the three-phase current and voltage in the circuit. A control cabinet electrically connected to the circuit breaker body and the detector, wherein the control cabinet is equipped with a controller that carries an instantaneous response module, a data collection module, a feature extraction module, a similarity matching module, a historical database, and a cache database for storing other temporary files and data, and the controller receives circuit parameter signals and controls the circuit breaker body.

[0012] The invention is further configured such that the control cabinet is also equipped with a design module that can adjust various parameters within the controller and a display for displaying the interface.

[0013] In summary, the present invention has the following beneficial effects: First, by detecting the magnitude of the three-phase current and the set magnitude of the three-phase current in three stages, that is, a total of 9 checks and comparisons are performed in a single test. When any three-phase current data is abnormal, the corresponding opening and closing actions can be performed to deal with complex situations in the circuit and increase safety. Secondly, by combining the instantaneous response module and intelligent judgment and closing, when an abnormal current occurs, the instantaneous response module first performs a tripping and closing operation. If the abnormality still exists, the instantaneous response module performs a tripping operation again. Whether to continue to try closing is determined based on the similarity between the current data and the data of previous faults. This can resolve instantaneous faults as quickly as possible, or reduce the need to attempt closing operations for permanent faults, thereby reducing losses. Furthermore, once the current fault type is confirmed, the corresponding data is stored for later comparison. Third, by extracting various features from the circuit system, the parameters of the faulty circuit can be displayed to the greatest extent, thereby increasing the accuracy of similarity judgment and facilitating the inspection of the corresponding circuit during subsequent maintenance, thus increasing maintenance efficiency. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the control logic of the recloser control method in this invention; Figure 2 This is a schematic flowchart of the recloser control method of the present invention. Figure 3 This is a schematic diagram of the reconciliation device in this invention.

[0015] In the picture: 11. Circuit breaker body; 12. Control cabinet. Detailed Implementation

[0016] The present invention will now be described in detail with reference to the accompanying drawings of the embodiments thereof.

[0017] Example

[0018] This automatic recloser uses a multi-stage time-limit overcurrent control method and its recloser, such as... Figures 1 to 3 As shown, the method includes: S1, during the recloser's monitoring of the circuit status, uses a monitor to acquire circuit parameters in real time, and then acquires switch parameters through the switch's own signal. This results in the real-time acquisition of switch position status, switch energy storage, instantaneous values ​​of three-phase current and three-phase voltage in the circuit, which are then sent to the time-limited data storage in the data collection module. Simultaneously, the switch position status, switch energy storage, and instantaneous values ​​of three-phase current are sent to the instantaneous response module. The instantaneous response module can promptly react to abnormal circuit conditions (opening or closing), while the time-limited data storage collects the corresponding data for later use or inspection. For data in the time-limited data storage, the earliest data is automatically deleted to clear memory. This enables instantaneous processing of abnormal data in the circuit and stores the corresponding circuit data. It is important to note that the data is timestamped during storage to ensure correct data retrieval.

[0019] S2, the instantaneous response module compares the instantaneous value of the three-phase current in the circuit with the set current value. When a data abnormality occurs, it will continuously initiate two actions of opening and closing the circuit breaker. There are three intervals where the data abnormality exists and three opening and closing methods are adopted, namely: immediate execution, execution after a delay according to the first set time, and execution after a delay according to the second set time. Preferably, a voltage and current recorder is used for circuit parameter detection, and any existing device capable of detecting and transmitting signals of switch status and mechanical energy storage status can be used for switch status detection, preferably a pressure sensor and an infrared position sensor. The three-phase currents Ia, Ib, and Ic are respectively related to a set current value Ia. 设 Ib 设 Ic 设 The system performs a comparison and activates when any one of the three-phase currents, Ia, Ib, or Ic, meets the condition. Furthermore, the three-phase currents need to be synchronously compared with three set current values, namely the set current value Ia. 设 Ib 设 Ic 设 Each circuit breaker has three setpoints. Different response speeds are used to delay the opening and closing actions when different setpoint current values ​​are met. When multiple setpoints need to be adjusted within a short period (multiple setpoints refer to Ia), adjustments are required. 设 Ib 设 Ic 设 For each of the three corresponding settings (i.e., the nine corresponding settings), the action with the shorter delay will be prioritized; specifically, the current value Ia is set. 设 The three set values, ranked from most urgent to least urgent, are: First Critical Value, Second Critical Value, and Third Critical Value. The set current value Ib... 设 Ic 设 Similarly, the lower the urgency level of the critical value, the closer it is to the safe current. When the first critical value is reached, the circuit breaker trips instantly. When the second critical value is reached, the circuit breaker trips after a first delay time. When the third critical value is reached, the circuit breaker trips after a second delay time. The second delay time is longer than the first delay time. In this way, sudden and serious faults can be tripped immediately, while for some small circuit fluctuations, a certain amount of time can be allowed for the power structure of the circuit breaker to store energy. This can also reduce the number of trips and reconnections. By tripping and reconnecting once to restore power, some faults can be directly eliminated.

[0020] S3, the instantaneous response module is also equipped with a status toggle signal board. When the instantaneous response module detects abnormal data and performs opening and closing actions, it synchronously sends a signal with a timestamp to the data collection module. The data collection module then retrieves all previous data and some future data within the time window centered on the timestamp from the time-limited data storage library. That is, the data received before and after the corresponding timestamp within a certain time range, and the data that needs to be received but has not yet been received. The preferred time range is the time range of at least ten data points. The specific time range can be adjusted according to the actual situation. When a fault data packet is formed, it is temporarily stored in the cache database. After the data is received, the corresponding fault data packet is sent to the feature extraction module. After receiving the fault data packet, the feature extraction module calculates the transient features, steady-state features and harmonic features, extracts the features, and forms a fault data feature packet. Preferably, the feature extraction module calculates the following based on the corresponding parameter data: current mutation amount, current mutation rate, current waveform parameters, fundamental effective value, negative sequence current, zero sequence current, and total harmonic distortion rate, and forms a fault data feature package from multiple feature parameters; Preferably, the method for calculating the current surge is as follows: Δi: Δi=i n -i （n-N） ; Δi: Sudden change in current; i n : Current current acquisition value; i （n-N） : Current sample value one cycle ago; Preferably, the rate of change of current is d(Δi) / dt; that is, the rate of change of Δi over time is calculated. Preferably, the current waveform parameters are A, B, φ, and ω. The Levenberg-Marquardt (LM) nonlinear least squares algorithm is used to decompose the fault current waveform into: i(t)=A·sin(ωt+φ)+B·e （-t / τ） ; And solve for the parameters A (AC amplitude), φ (phase angle), B (DC initial value) and τ (attenuation time constant); Where τ = L / R, theoretically a constant; A reflects the severity of the fault; Φ reflects the phase relationship between voltage and current at the instant of the fault, and is related to the fault type and line parameters; the magnitude of B is directly related to the time of fault occurrence (voltage phase angle), and the value of B is the largest when the fault occurs at the voltage zero-crossing point; the specific calculation methods for the above current waveform parameters are as follows: First, obtain the sampling time points: t0, t1, t2, ..., t n ; and the corresponding current measurement values: i0, i1, i2, ..., i n ; Let's establish a least squares optimization problem: minΣ[i model (t) k -i measured (t) k )]² k ranges from 0 to n; Where: i model (t) = A·sin(ωt+φ)+B·e （-t / τ） ; i model The current value calculated by the mathematical model; i measured The actual measured current value is used to minimize the sum of squared residuals between the digital model's calculated value and the actual measured value. Finally, the corresponding A, B, φ, and ω parameter values ​​are output. By calculating the corresponding parameter values, data support is provided for subsequent data category judgment and classification of the fault, and the abnormal characteristics in the fault data are further extracted to facilitate judgment.

[0021] S4, transmit the extracted data to the similarity matching module and perform similarity judgment with the data in the historical database, and mark the data packet after the current data feature extraction as permanent fault, transient fault, or fault of undetermined type; Furthermore, similarity determination requires data preprocessing, followed by calculating the similarity of the two dimensions using both Euclidean distance and cosine similarity methods, and finally taking the final similarity score. Final similarity = 0.4 Euclidean distance similarity + 0.6 cosine similarity; Given two n-dimensional vectors X = (X1, X2, ..., X...), ... n ) and Y = (Y1, Y2, ..., Y n ); Euclidean distance similarity = ; in: x i y: The i-th feature value of the current fault feature vector; i : The i-th eigenvalue of the historical fault feature vector; n: The dimension of the feature vector (i.e., the feature parameters calculated in step S3); Σ: The summation of i from 1 to n; Cosine similarity = (X·Y) / (||X||·||Y||); in: X·Y is the dot product (inner product) of vectors X and Y; ||X|| is the magnitude (length) of vector X; ||Y|| is the magnitude (length) of vector Y. Since the accuracy of different similarity judgment methods varies depending on the situation, combining the two judgment methods with a weight of 4:6 for the final similarity is more accurate and in line with the actual situation. Similarity is calculated separately from the "transient fault database" and the "permanent fault database" (both are further classifications of the historical database). Several samples with the highest similarity are selected from each database to form transient and permanent sets respectively. The number is selected according to the actual situation and conditions, preferably 8. The average similarity of each pair of sets is calculated separately, and the average similarity of the two sets is judged. If the average similarity of the transient set is greater than that of the permanent set and the similarity is greater than 75%, the fault is identified as transient and marked as transient. Otherwise, it is marked as permanent. If the similarity is the same or less than 75%, it is identified as a fault type that cannot be determined and marked accordingly. This can more accurately and precisely determine the corresponding fault type.

[0022] S5, for permanent faults, the circuit will be closed a maximum of two times; for transient faults and faults whose type cannot be determined, the circuit will be closed a maximum of five times and three times respectively, and a different interval time will be set for each closing. If the fault is not resolved after reaching the maximum number of closing times, the circuit will be locked in the open state and wait for maintenance personnel. The process will end when the fault is resolved. The final type of the aforementioned fault is synchronously fed back to the historical database.

[0023] A type of reconcile, such as Figure 2-3 As shown, it includes: The circuit breaker body 11 performs current opening and closing actions when receiving signals. The circuit breaker body 11 is also equipped with detectors for detecting the three-phase current and voltage in the circuit. The control cabinet 12 is electrically connected to the circuit breaker body 11 and the detector. The control cabinet 12 is equipped with a controller that carries a transient response module, a data collection module, a feature extraction module, a similarity matching module, a historical database, and a cache database for storing other temporary files and data. The controller receives circuit parameter signals and controls the circuit breaker body 11. The controller is preferably a programmable logic controller.

[0024] like Figure 3 As shown, the control cabinet 12 is also equipped with a design module that can adjust various parameters within the controller and a display for showing the interface; By separating the circuit breaker body 11 and the control cabinet 12, the control cabinet 12 can be placed in a relatively safe and suitable location. If conditions permit, temperature and humidity control devices can also be installed in the control cabinet 12 to ensure the normal operation of the electronic components inside the control cabinet 12. At the same time, the control cabinet 12 can be placed far away from the circuit breaker body 11, which also makes it convenient for equipment maintenance personnel to check the status of the recloser through the control cabinet 12, and also facilitates the adjustment of various parameters of the recloser, such as adjusting the closing time and the maximum number of closing attempts under different conditions. This allows for further adjustments based on actual usage conditions and increases the fault diagnosis rate, thereby improving the usability of the equipment. Furthermore, a communication module can be set up to remotely transmit the operating status of the recloser and the corresponding detection data to the power control center for real-time monitoring of the circuit status. Furthermore, the power control center can also remotely adjust the corresponding parameters of the recloser to achieve remote control; this enables digital control and enhances the user experience.

[0025] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A multi-stage time-limit overcurrent control method for an automatic recloser, characterized in that, The method includes: S1, during the process of the recloser monitoring the circuit status, acquires circuit parameters and switching parameters in real time, and sends the corresponding parameters to the time-limited data storage library in the instantaneous response module and the data collection module respectively. S2, the instantaneous response module compares the instantaneous value of the three-phase current in the circuit with the set current value. When a data abnormality occurs, it will continuously initiate two actions of opening and closing the circuit breaker. There are three intervals where the data abnormality exists and three opening and closing methods are adopted, namely: immediate execution, execution after a delay according to the first set time, and execution after a delay according to the second set time. S3, when the circuit parameter data is abnormal, a signal with a timestamp is sent to the data collection module. The data collection module then retrieves all previous data and some future data within the time window centered on the timestamp from the time-limited data storage library and sends it to the feature extraction module. After receiving the fault data packet, the feature extraction module calculates the transient characteristics, steady state and harmonic characteristic parameters, extracts the features, and forms a fault data feature packet. S4, transmit the extracted data to the similarity matching module and perform similarity judgment with the data in the historical database, and mark the data packet after the current data feature extraction as permanent fault, transient fault, or fault of undetermined type; S5, for permanent faults, the circuit will be closed a maximum of two times; for transient faults and faults whose type cannot be determined, the circuit will be closed a maximum of five times and three times respectively, and a different interval time will be set for each closing. If the fault is not resolved after reaching the maximum number of closing times, the circuit will be locked in the open state and wait for maintenance personnel. The process will end when the fault is resolved. The final type of the aforementioned fault is simultaneously fed back to the historical database.

2. The multi-segment time-limit overcurrent control method for automatic recloser according to claim 1, characterized in that, The circuit parameters in S1 include the instantaneous values ​​of the three-phase current and the three-phase voltage in the circuit. The switching parameters include the switch position state and the switch energy storage state. All data parameters are packaged and transmitted to the data collection module and timestamped. Then, they are stored in the time-limited data storage library. The data of the instantaneous values ​​of the three-phase current, the switch position state, and the switch energy storage state in the circuit are transmitted to the instantaneous response module.

3. The multi-segment time-limit overcurrent control method for automatic recloser according to claim 2, characterized in that, The three-phase currents Ia, Ib, and Ic are respectively related to the set current value Ia 设 Ib 设 Ic 设 The system compares the three-phase currents and takes action when any one of the three-phase currents, Ia, Ib, or Ic, meets the conditions. The three-phase currents are compared synchronously with three set current values. Different reaction speeds are used to delay the opening and closing actions when different set current values ​​are met. When multiple set adjustments are met in a short period of time, the action with the shorter delay is preferred.

4. The multi-segment time-limit overcurrent control method for automatic recloser according to claim 3, characterized in that, The instantaneous response module is also equipped with a status toggle signal module. When the instantaneous response module detects abnormal data and performs opening or closing actions, it synchronously sends a signal with a timestamp to the data collection module.

5. The multi-segment time-limit overcurrent control method for automatic recloser according to claim 4, characterized in that, The feature extraction module calculates the following based on the corresponding parameter data: current mutation amount, current mutation rate, current waveform parameters, fundamental effective value, negative sequence current, zero sequence current, and total harmonic distortion rate, and forms a fault data feature package from multiple feature parameters.

6. The multi-segment time-limit overcurrent control method for automatic recloser according to claim 5, characterized in that, Similarity determination requires data preprocessing, followed by calculating the similarity across two dimensions using both Euclidean distance and cosine similarity methods, and finally taking the final similarity score. Final similarity = 0.4 Euclidean distance similarity + 0.6 cosine similarity.

7. A recloser, used in the multi-segment time-limit overcurrent control method for automatic recloser as described in claims 1-6, characterized in that, include: The circuit breaker body (11) performs current opening and closing actions when receiving signals. The circuit breaker body (11) is also equipped with a detector for detecting the three-phase current and voltage in the circuit. A control cabinet (12) electrically connected to the circuit breaker body (11) and the detector is provided in the control cabinet (12), which is equipped with a controller that carries an instantaneous response module, a data collection module, a feature extraction module, a similarity matching module, a historical database, and a cache database that stores other temporary files and data. The controller receives circuit parameter signals and controls the circuit breaker body (11).

8. A recloser according to claim 7, characterized in that, The control cabinet (12) is also equipped with a design module that can adjust the parameters in the controller and a display for displaying the interface.

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