A method for overstep tripping self-healing and magnetic control cable branch box

Abstract

This invention belongs to the field of trip self-healing technology, specifically relating to a method for cascading trip self-healing and a magnetically controlled cable branch box. The method includes: in response to detecting a cascading trip of an upstream magnetically controlled circuit breaker, acquiring fault current data recorded by the magnetically controlled circuit breakers of each outgoing branch under the jurisdiction of the upstream magnetically controlled circuit breaker during the fault period; calculating the fault current ratio of each outgoing branch to the sum of the fault currents of all outgoing branches based on the fault current data of each outgoing branch; comparing the fault current ratio of each outgoing branch with a preset threshold, and determining that the outgoing branch is a faulty branch when the fault current ratio of a certain outgoing branch is greater than or equal to the preset threshold; sending a tripping command to the magnetically controlled circuit breaker of the faulty branch to isolate the faulty branch; and after confirming that the faulty branch is successfully isolated, controlling the upstream magnetically controlled circuit breaker to perform a reclosing operation to restore power supply to the non-faulty branches.

Description

Technical Field

[0001] This invention belongs to the field of trip self-healing technology, specifically relating to a method for over-level trip self-healing and a magnetically controlled cable branch box. Background Technology

[0002] The primary function of a cable distribution box is to branch or transfer low-voltage cables. Traditional floor-mounted distribution boxes typically have one inlet and three outlets, using knife-fuse switches and equipped with an emergency power interface. To collect electrical data from the incoming and outgoing lines, a low-voltage monitoring unit is installed to collect voltage, current, and power data within the box. For environmental data collection, temperature and humidity sensors, smoke detectors, and water immersion sensors are added to provide alarms for temperature, humidity, smoke, and water immersion. When an overcurrent or short-circuit fault occurs, the fuse blows, clearing the fault. The low-voltage monitoring unit reports the fault information, and maintenance personnel arrive on-site to troubleshoot. After the fault is resolved, the fuse is replaced to restore power. However, the fuse relies on overcurrent heating to blow, resulting in a physical delay between the fault occurrence and its melting. The short-circuit fault current can cause equipment damage or even fire within tens of milliseconds. Furthermore, the delayed clearing can cause downstream equipment to experience excessive short-circuit current, leading to secondary faults.

[0003] Chinese invention patent CN104821489A discloses a cable branch box, including a box body, a box door, and horizontally arranged inlet busbars, outlet busbars, and ground busbars inside the box. The inlet busbar is equipped with an inlet circuit breaker, and the outlet busbar is equipped with an outlet circuit breaker. The inlet circuit breaker is connected to the outlet circuit breaker through a busbar. By connecting the inlet and outlet circuit breakers through a stacked busbar, the wiring inside the box is reduced, which meets the requirements of thermal and electrical stress caused by possible short circuits during operation. However, this device cannot automatically cut off circuit faults, which poses a safety hazard, and it cannot quickly switch power to restore power supply, affecting the user's normal power use. Summary of the Invention

[0004] The purpose of this invention is to provide a self-healing method for cascading tripping and a magnetically controlled cable branch box, which solves the problem in the background art that there is a physical delay between the outgoing line fault of the low-voltage cable branch box and the melting, which can easily lead to equipment damage or even secondary faults, and the power supply cannot be restored quickly.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a self-healing method for cascading tripping, comprising the following steps: In response to the detection of an over-tripping of the upstream magnetically controlled circuit breaker, the fault current data recorded by the magnetically controlled circuit breakers of each outgoing branch under the jurisdiction of the upstream magnetically controlled circuit breaker during the fault period are obtained. Based on the fault current data of each outgoing branch, calculate the proportion of the fault current of each outgoing branch to the sum of the fault currents of all outgoing branches. The fault current ratio of each outgoing branch is compared with a preset threshold. When the fault current ratio of a certain outgoing branch is greater than or equal to the preset threshold, the outgoing branch is determined to be a faulty branch. Send a trip command to the magnetically controlled circuit breaker of the faulty branch to isolate the faulty branch; After confirming that the faulty branch has been successfully isolated, the upstream magnetic circuit breaker is controlled to perform a reclosing operation to restore power supply to the non-faulty branch.

[0006] Preferably, the step of calculating the percentage of the fault current of each outgoing branch relative to the sum of the fault currents of all outgoing branches based on the fault current data of each outgoing branch includes: Extract the instantaneous fault current value of each outgoing branch at the moment of fault occurrence from the fault current data recorded by the magnetically controlled circuit breakers of each outgoing branch. , , ..., ,in n This represents the total number of outgoing branches; Align the instantaneous fault current values ​​of each outgoing branch to ensure that the current sampling time of all branches corresponds to the same fault time section. Calculate the sum of the instantaneous values ​​of the fault current in all outgoing branches:

[0007] Calculate the instantaneous fault current value for each outgoing branch. The ratio of the fault current to the total current gives the proportion of fault current in that branch: ; Output the percentage of fault current for each outgoing branch. , , ..., .

[0008] Preferably, the step of comparing the fault current ratio of each outgoing branch with a preset threshold, and determining that the outgoing branch is a faulty branch when the fault current ratio of a certain outgoing branch is greater than or equal to the preset threshold, includes: Obtain a pre-set fault determination threshold K, wherein the value of K ranges from 0.6 to 0.9; The fault current percentage of each outgoing branch is calculated sequentially. Compare with the threshold K; If there exists an outgoing branch m that satisfies If so, then mark the branch as a candidate faulty branch; Verify the uniqueness of the candidate faulty branch: if only one outgoing branch satisfies... If multiple outgoing branches simultaneously meet the condition, then the branch is directly determined to be a faulty branch; Then select The branch with the largest value is designated as the faulty branch, and this abnormal situation is reported as an alarm message. Output fault branch identifier.

[0009] Preferably, the step of sending a trip command to the magnetically controlled circuit breaker of the faulty branch to isolate the faulty branch includes: Based on the fault branch identifier, generate a tripping control command for the magnetic circuit breaker of that branch; The station-side IoT unit sends a tripping command to the magnetic circuit breaker of the faulty branch and records the time of command transmission. The switch position status of the magnetic circuit breaker in the faulty branch is collected after a preset time window Δt. Determine whether the collected switch position status is in the open position: If the circuit is in the tripped position, confirm that the faulty branch has been successfully isolated and record the isolation completion time. ; If the circuit breaker is not in the open position, the isolation is determined to have failed. The delay preset time window steps are repeated. If the circuit breaker is still not successfully opened after repeating the preset number of times, the subsequent reclosing operation is blocked and an operation and maintenance alarm is reported. Output the isolation success flag and the isolation completion time. .

[0010] Preferably, after confirming that the faulty branch has been successfully isolated, controlling the upstream magnetically controlled circuit breaker to perform a reclosing operation to restore power supply to the non-faulty branch specifically includes the following sub-steps: At the time of completion of quarantine Based on this, the delayed reclosing waiting time Ensure that the faulty branch has been completely disconnected; Before the delay ends, collect the current of the branch box busbar. and judge Is it less than the rated current? : like < If so, reclosing is permitted; like ≥ If the busbar is found to be in a state of continuous fault, reclosing should be suspended and an anomaly should be reported. The station-end IoT unit sends a closing command to the upper-level magnetically controlled circuit breaker to control it to perform a reclosing operation.

[0011] Preferred options also include: After sending the closing command, a preset time window is delayed to collect the switch position status of the upstream magnetically controlled circuit breaker and bus voltage and current data. Determine if reclosing was successful: If the upstream magnetic circuit breaker is in the closed position, and the bus voltage recovers to more than 90% of the rated voltage, and the current of the non-faulty branch is normal, then the reclosing is considered successful and the self-healing process is completed. If the upstream magnetically controlled circuit breaker fails to close successfully, or if a fault current is detected again after closing, it is determined that the reclosing is a permanent fault. The upstream circuit breaker should be immediately locked, and reclosing should be prohibited. The incident should be reported to the maintenance personnel for on-site handling.

[0012] In a second aspect, the present invention provides a magnetically controlled cable branch box, which applies the aforementioned cascading trip self-healing method, comprising: SMC insulated enclosure with built-in busbars and acrylic insulating panels; The low-voltage magnetically controlled circuit breaker is communicatively connected to the station-end IoT unit and is used to detect electrical parameters inside the enclosure. It includes an incoming magnetically controlled circuit breaker and an outgoing magnetically controlled circuit breaker, wherein the incoming magnetically controlled circuit breaker is connected in series with the outgoing magnetically controlled circuit breaker via a busbar. The environmental monitoring module communicates with the station-end IoT unit to detect environmental data inside the enclosure; The station-side IoT unit connects the low-voltage magnetically controlled circuit breaker and the environmental monitoring module, and is used to receive the electrical parameters and environmental data, determine whether there is a fault, and upload them to the cloud. The generator vehicle quick interface, connected to the busbar, is used to quickly connect to power from the emergency generator vehicle in an emergency. It consists of four quick connectors, which correspond to the three phases A, B, and C and the neutral line N, respectively. In the cloud, it is used to receive fault signals from the station-side IoT units and issue disconnection commands, and issue recovery commands after the fault is recovered; The Bluetooth communication module is built into the station-side IoT unit and the low-voltage magnetic circuit breaker. The Bluetooth communication module is connected to an external handheld terminal for remotely sending commands via the Bluetooth communication module to control the opening and closing of the low-voltage magnetic circuit breaker.

[0013] Preferably, the low-voltage magnetically controlled circuit breaker includes an incoming magnetically controlled circuit breaker and several outgoing magnetically controlled circuit breakers, with the outgoing magnetically controlled circuit breakers connected in parallel and the incoming magnetically controlled circuit breaker and the outgoing magnetically controlled circuit breakers connected in series.

[0014] Preferably, the environmental monitoring module integrates a temperature and humidity sensor, a smoke sensor, a water immersion sensor, and a door magnetic sensor. The environmental data includes the temperature, humidity, door magnetic status, water immersion, and smoke concentration inside the enclosure.

[0015] Preferably, the integrated temperature and humidity sensor, smoke sensor, water immersion sensor and door magnetic sensor are located on the top of the cabinet; The generator car quick interface is located above the low-voltage magnetic circuit breaker, and the station-end IoT unit is located above the low-voltage magnetic circuit breaker. The enclosure is equipped with a partition, which is an L-shaped plate, and is located between the station-end IoT unit and the generator car quick interface; The guard plate is located between the low-voltage magnetic circuit breaker and the generator car quick interface. The guard plate and the partition are vertically distributed, and the height of the guard plate is lower than that of the partition.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: By calculating the proportion of fault current in each outgoing branch and comparing it with a preset threshold, the true faulty branch can be identified. This enables rapid location of the fault point after a cascading trip occurs, avoiding misjudgments caused by dispersed fault currents or the simultaneous presence of fault characteristics in multiple branches. This facilitates subsequent accurate isolation and automatic reclosing. The processing time for cascading trips is reduced from hours of manual investigation to seconds of automatic decision-making, enabling rapid disconnection of faulty circuits, avoiding secondary faults, and improving the power supply reliability of the distribution network. By extracting the instantaneous current values ​​of each outgoing branch at the moment of the fault and aligning the sampling times between multiple branches, it is ensured that all current data correspond to the same fault time section, eliminating the calculation error introduced by the asynchronous sampling of each circuit breaker, making the calculation results of the fault current ratio more accurate and reliable, and providing high-quality data for subsequent fault branch determination. The specific logic for threshold comparison and fault branch determination is defined. By setting a fault determination threshold K of 0.6-0.9 and introducing a uniqueness verification mechanism for candidate fault branches, when only one branch meets the threshold condition, it is directly determined as a fault branch; when multiple branches meet the threshold condition simultaneously, the branch with the highest percentage is selected as the fault branch and the anomaly is reported. This enables fault location and identification of complex fault scenarios, providing maintenance personnel with more complete fault information. Based on conventional amplitude-frequency-phase synchronization, inductance, capacitance and inertia are calculated. The supercapacitor replenishes energy as needed 2 ms in advance, and then injects 3% anti-phase sequence voltage to actively cancel residual inrush current. Residual disturbances are absorbed by the buffer module. Active pre-execution compresses the entire switching process to within 40 ms, achieving seamless switching and ensuring that the load of important users will not be interrupted. By integrating a low-voltage magnetically controlled circuit breaker, a station-end IoT unit, an environmental monitoring module, a generator truck quick-connect interface, and cloud and Bluetooth communication modules into a single unit, the branch box achieves an intelligent and streamlined design. The low-voltage magnetically controlled circuit breaker features rapid opening and closing characteristics and remote control functions, providing hardware support for cascading trip self-healing methods. The station-end IoT unit, acting as a data hub, enables unified aggregation and uploading of multi-source information. The four-phase design (A, B, C, N) of the generator truck quick-connect interface supports rapid access to emergency power supplies. The Bluetooth communication module enables contactless local operation, ensuring personal safety. This branch box provides a complete technical platform at the hardware level for advanced functions such as cascading trip self-healing, emergency power supply, and uninterrupted maintenance. The low-voltage magnetic circuit breaker can collect power parameters of incoming and outgoing lines in real time, and the environmental monitoring module can collect environmental parameters inside the branch box in real time, realizing transparent real-time perception of the cable branch box, which facilitates fault prevention and early warning. All information from the branch boxes is aggregated and sent to the main station through the station-side IoT unit, eliminating the need for a communication module for each switch and saving communication bandwidth and modules. The station-side IoT unit and low-voltage magnetic circuit breaker have built-in Bluetooth, enabling local handheld tools to control the opening and closing of the magnetic circuit breaker, achieving contactless power outage and restoration, and ensuring personal safety. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart of a self-healing method for over-level tripping according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the structure of a magnetically controlled cable branch box according to Embodiment 2 of the present invention; Figure 3 This is an electrical schematic diagram of a magnetically controlled cable branch box according to Embodiment 2 of the present invention.

[0018] Reference numerals: 1. Enclosure; 2. Low-voltage magnetic circuit breaker; 3. Protective plate; 4. Quick interface for generator car; 5. Station-end IoT unit; 6. Sensor; 7. Partition. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0020] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0021] Example 1 like Figure 1 As shown, a self-healing method for cascading tripping includes the following specific steps: S1. In response to the detection of an over-tripping of the upper-level magnetic circuit breaker, acquire the fault current data recorded by the magnetic circuit breakers of each outgoing branch under the jurisdiction of the upper-level magnetic circuit breaker during the fault period. Specifically, the identification of cascading tripping by the upstream magnetically controlled circuit breaker includes: The upstream / downstream magnetically controlled circuit breaker collects current and voltage data in real time, with a sampling frequency of not less than 1kHz, and triggers waveform recording when a fault occurs. Short circuit fault determination: When the current of a certain phase meets the following conditions... And phase voltage ( (Rated phase voltage), determined to be a short circuit fault, set =1; Fault timing calibration: based on the moment of sudden current change. As the fault initiation time.

[0022] An out-of-level trip is determined to have occurred when the following three conditions are met: Condition 1: and ; The fault current reaches the setting value of the downstream switch. And the upstream switch current simultaneously reaches the upstream switch setting value. This indicates that the fault point is located downstream of the branch box; Condition 2: ; Upper-level switch tripping event Less than the setting value of the lower-level switch This means that the upstream switch has tripped before the downstream switch has reached its operating time. Condition 3: ; This is the flag for the operation of the lower-level switch. 0 indicates that the lower-level switch has not been opened, and 1 indicates that it has been opened.

[0023] S2. Based on the fault current data of each outgoing branch, calculate the proportion of the fault current of each outgoing branch to the sum of the fault currents of all outgoing branches. Specifically: Extract the instantaneous fault current value of each outgoing branch at the moment of fault occurrence from the fault current data recorded by the magnetically controlled circuit breakers of each outgoing branch. , , ..., ,in n This represents the total number of outgoing branches; Align the instantaneous fault current values ​​of each outgoing branch to ensure that the current sampling time of all branches corresponds to the same fault time section. Calculate the sum of the instantaneous values ​​of the fault current in all outgoing branches: ; Calculate the instantaneous fault current value for each outgoing branch. The ratio of the fault current to the total current gives the proportion of fault current in that branch: ; Output the percentage of fault current for each outgoing branch. , , ..., .

[0024] S3. Compare the fault current ratio of each outgoing branch with a preset threshold. When the fault current ratio of a certain outgoing branch is greater than or equal to the preset threshold, the outgoing branch is determined to be a faulty branch. Specifically: S31. Obtain the preset fault determination threshold. K The K The value range is 0.6-0.9; Preferred, K Take 0.8; S32. Sequentially calculate the percentage of fault current for each outgoing branch. With the threshold K Compare; S33. If there exists an outgoing branch m that satisfies... If so, then mark the branch as a candidate faulty branch; S34. Verify the uniqueness of the candidate faulty branch: If only one outgoing branch satisfies the condition... If multiple outgoing branches simultaneously meet the condition, then the branch is directly determined to be a faulty branch; Then select The branch with the largest value is designated as the faulty branch, and this abnormal situation is reported as an alarm message. S35, Output fault branch identifier.

[0025] S4. Send a trip command to the magnetic circuit breaker of the faulty branch to isolate the faulty branch; after a 0.1s delay after tripping, collect the switch position. If the switch position is in the open position, the isolation is successful.

[0026] Specifically: S41. Based on the fault branch identifier, generate a tripping control command for the magnetic circuit breaker of that branch; S42. Send a tripping command to the magnetic circuit breaker of the faulty branch through the station-end IoT unit, and record the time of command transmission; S43. Delay a preset time window Δt to collect the switching position status of the magnetic circuit breaker of the faulty branch; S44. Determine whether the collected switch position status is in the open position: If the circuit is in the tripped position, confirm that the faulty branch has been successfully isolated and record the isolation completion time. After an over-level trip, the upstream switch is in the open state. Reclosing must be performed after the fault is isolated. The reclosing time is... satisfy: ; in, The time consumed for isolating the faulty branch. ≤0.5s; If the circuit breaker is not in the open position, the isolation is determined to have failed. The delay preset time window steps are repeated. If the circuit breaker is still not successfully opened after repeating the preset number of times, the subsequent reclosing operation is blocked and an operation and maintenance alarm is reported. S44. Output isolation success flag and isolation completion time. .

[0027] S5. After confirming that the faulty branch has been successfully isolated, control the upstream magnetic circuit breaker to perform a reclosing operation to restore power supply to the non-faulty branch.

[0028] Specifically: S51, at the moment of completion of isolation Based on this, the delayed reclosing waiting time Ensure that the faulty branch has been completely disconnected; S52. Before the delay ends, collect the current current of the branch box busbar. and judge Is it less than the rated current? : like < If so, reclosing is permitted; like ≥ If the fault is detected, it is determined that there may be a persistent fault on the busbar. Reclosing is suspended and the abnormality is reported to avoid reclosing to the fault. S53. Send a closing command to the upper-level magnetic circuit breaker through the station-end IoT unit to control it to perform a reclosing operation; S54. After sending the closing command, delay for a preset time window and collect the switch position status of the upper magnetic circuit breaker and bus voltage and current data. S55. Determine if the reclosing was successful: If the upstream magnetically controlled circuit breaker is in the closed position and If the reclosing is successful, the self-healing process is complete. If the upstream magnetically controlled circuit breaker fails to close successfully, or if a fault current is detected again after closing, it is determined that the reclosing is a permanent fault. The upstream circuit breaker should be immediately locked, and reclosing should be prohibited. The incident should be reported to the maintenance personnel for on-site handling.

[0029] As a preferred example of the above embodiments, a seamless power switching method is adopted when closing the circuit breaker, which specifically includes the following steps: Real-time acquisition of voltage and current parameters of the main grid power supply and generator vehicle power supply, and identification of the inductance, capacitance and inertia of the current load; When a switching trigger condition is detected, the energy storage unit pre-compensates the load with energy within a preset time window based on the identified load inertia. While performing energy pre-compensation, the voltage amplitude, frequency, and phase of the main grid power supply and the generator vehicle power supply are simultaneously detected. When the synchronization condition is detected to be met, a voltage with a preset amplitude of reverse phase sequence is injected into the magnetically controlled circuit breaker on the generator vehicle side, and a closing command is sent to the magnetically controlled circuit breaker on the generator vehicle side at the predicted voltage zero crossing point. At the same time or shortly after the magnetic circuit breaker on the generator car side is closed, the incoming magnetic circuit breaker is opened to complete the seamless switching from the main grid power supply to the generator car power supply.

[0030] Specifically, the synchronization conditions are as follows: Voltage amplitude matching: The voltage amplitudes of the main power grid and the generator car power supply are collected by the low-voltage magnetic circuit breaker, and the difference between the two is calculated to ensure that the voltage amplitude difference between the two power supplies is less than 5% at the moment of switching; Frequency matching: The frequencies of the main power grid and the generator car power supply are calculated using the Fast Fourier Transform algorithm to ensure that the frequency difference between the two power supplies is less than 0.1Hz; Phase matching: The phase difference between the main grid and the generator car power supply is calculated using a phase-locked loop (PLL) algorithm to ensure that the phase difference between the two power supplies is less than 5°.

[0031] As a specific example of the above embodiments, the inductance and capacitance inertia of the current load are detected in real time by the load inertia identification unit, and the energy storage compensation unit performs energy pre-compensation as needed by the supercapacitor 2ms before switching; at the moment of closing, a voltage vector of 3% of the rated voltage in the reverse phase sequence is injected into the magnetic control circuit breaker on the generator side to actively cancel the residual magnetism and excitation inrush current of the transformer or line, and the residual transient disturbance is absorbed by the buffer module. By adopting a predictive zero-crossing control algorithm, the closing command is issued in advance based on system delay modeling, transforming the traditional passive waiting synchronous switching into active pre-execution control; Through the synergistic effect of the above steps, the entire power switching time is compressed to less than 40ms, achieving seamless switching with zero voltage sag and zero current surge.

[0032] Example 2 like Figures 2-3 As shown, a magnetically controlled cable branch box includes: The SMC insulated enclosure 1 has an internal busbar and an acrylic insulated protective plate 3. The SMC (Sheet Molding Compound) material has UV resistance and high mechanical strength. Combined with the arc resistance of the acrylic protective plate 3, the overall insulation resistance of the enclosure 1 is ≥100MΩ, effectively preventing leakage accidents in humid environments. The low-voltage magnetically controlled circuit breaker 2 is used to detect the power supply parameters on the main power grid side inside the enclosure 1. It includes an incoming magnetically controlled circuit breaker and an outgoing magnetically controlled circuit breaker. The incoming magnetically controlled circuit breaker is connected in series with the outgoing magnetically controlled circuit breaker via a busbar. The power supply parameters on the main power grid side include the voltage amplitude, current, power, frequency, harmonics, or node temperature of the incoming and outgoing lines. Specifically, the low-voltage magnetically controlled circuit breaker 2 adopts a low-voltage magnetically controlled circuit breaker 2 with a magnetic control mechanism. This series of circuit breakers takes magnetic control technology as its core and achieves precise contact action control through the magnetic control mechanism. Its working principle is based on electromagnetic induction and magnetic field action. When overload, short circuit or other fault currents occur in the circuit, the magnetic control mechanism can respond quickly and drive the contacts to disconnect the circuit, thereby cutting off the fault current and protecting the equipment and line safety.

[0033] The low-voltage magnetically controlled circuit breaker 2 has three remote functions: it can collect three-phase voltage, current, power, switch position, etc., and judge faults such as short circuit, overcurrent, overload, undervoltage, and overvoltage in real time, and realize rapid fault isolation on the spot; it has a remote control function, which can realize remote power outage and power restoration; it has a topology identification function, which supports automatic topology identification and fault analysis of the transformer area; at the same time, when used with the trolley circuit breaker, it can realize zero-sensory power supply switching for users and uninterrupted power supply during planned maintenance.

[0034] The environmental monitoring module is connected to the station-end IoT unit 5 and is used to detect environmental data inside the box 1. The environmental data includes the temperature, humidity, smoke concentration, door status and water immersion status inside the box. The station-side IoT unit 5 connects the low-voltage magnetically controlled circuit breaker 2 and the environmental monitoring module, and is used to receive power parameters and environmental data from the main power grid side, determine whether there is a fault, and upload the data to the cloud. As a preferred example of the above embodiments, the station-side IoT unit 5 interacts with the low-voltage magnetically controlled circuit breaker 2 and the environmental monitoring module via an RS485 bus, collects the operating status information of the low-voltage magnetically controlled circuit breaker 2 and the environmental data provided by the environmental monitoring module, and uploads them to the smart converged terminal of the distribution area and the cloud master station.

[0035] The generator vehicle quick interface 4 is connected to the busbar and is used to quickly connect to the power supply from the emergency generator vehicle in an emergency. The generator vehicle quick interface 4 consists of four quick connectors. The busbar includes an A-phase busbar, a B-phase busbar, a C-phase busbar, and an N-phase busbar. The four quick connectors are respectively connected to the A-phase busbar, the B-phase busbar, the C-phase busbar, and the N-phase busbar. The cloud-based system receives fault signals from the station-side IoT unit 5 and issues cut-off commands. Once the fault is resolved, it issues recovery commands.

[0036] Specifically, the disconnection commands include the incoming magnetic circuit breaker tripping command, the outgoing magnetic circuit breaker tripping command, and the generator car magnetic circuit breaker tripping command.

[0037] Specifically, the recovery commands include closing commands for incoming magnetic circuit breakers, closing commands for outgoing magnetic circuit breakers, and closing commands for generator car magnetic circuit breakers.

[0038] As a preferred example of the above embodiments, the cloud can also issue switching instructions.

[0039] As a preferred example of the above embodiments, the low-voltage magnetically controlled circuit breaker 2 includes a plurality of incoming magnetically controlled circuit breakers with a rated current of 400A and a plurality of outgoing magnetically controlled circuit breakers with a rated current of 250A. The plurality of outgoing magnetically controlled circuit breakers are connected in parallel, and the incoming magnetically controlled circuit breaker and the plurality of outgoing magnetically controlled circuit breakers are connected in series.

[0040] As a preferred example of the above embodiments, the housing 1 is provided with a mounting bracket for installing the low-voltage magnetic circuit breaker 2. The low-voltage magnetic circuit breaker 2 and the mounting bracket are detachably connected. In use, different numbers of incoming magnetic circuit breakers and outgoing magnetic circuit breakers can be set as needed to adapt to different requirements.

[0041] As an optional example of the above embodiments, the number of incoming magnetic circuit breakers is 1, and the number of outgoing magnetic circuit breakers is 3.

[0042] As an optional example of the above embodiments, the number of incoming magnetic circuit breakers is 1, and the number of outgoing magnetic circuit breakers is 4.

[0043] As an optional example of the above embodiments, the number of incoming magnetic circuit breakers is 2, and the number of outgoing magnetic circuit breakers is 4.

[0044] As a preferred example of the above embodiments, the environmental monitoring module integrates a temperature and humidity sensor, a smoke sensor, a water immersion sensor, and a door magnetic sensor. The environmental data includes the temperature, humidity, door magnetic status, water immersion, and smoke concentration inside the enclosure 1.

[0045] As a preferred example of the above embodiments, the integrated temperature and humidity sensor, smoke sensor, water immersion sensor and door magnetic sensor are disposed on the top of the housing 1; The generator car quick interface 4 is located above the low-voltage magnetic circuit breaker 2, and the station-end IoT unit 5 is located above the low-voltage magnetic circuit breaker 2. As a preferred example of the above embodiment, the faults are short circuit, overcurrent, overload, undervoltage, and overvoltage faults.

[0046] As a preferred example of the above embodiment, the enclosure 1 is provided with a partition 7, which is an L-shaped plate. The partition 7 is located between the station-end IoT unit 5 and the generator car quick interface 4. The protective plate 3 is located between the low-voltage magnetic circuit breaker 2 and the generator car quick interface 4. The protective plate 3 and the partition 7 are vertically distributed, and the height of the protective plate 3 is lower than that of the partition 7. Existing cable branch boxes have many cables inside, which can easily lead to internal failures. In this application, the enclosure 1 is separated by the partition 7 and the protective plate 3, ensuring that the inside of the enclosure 1 is tidy.

[0047] As a preferred example of the above embodiments, the partition 7 is bolted and placed inside the housing 1.

[0048] As a preferred example of the above embodiments, the protective plate 3 is bolted and placed inside the housing 1.

[0049] Example 2 Example 2, as a preferred embodiment, also includes a Bluetooth communication module, which is built into the station-end IoT unit 5 and the low-voltage magnetic circuit breaker 2. The Bluetooth communication module is connected to an external handheld terminal, which is used by the operator to remotely send commands through the Bluetooth communication module to control the opening and closing of the low-voltage magnetic circuit breaker 2, so as to realize contactless power outage and power supply and ensure personal safety.

[0050] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A self-healing method for cascading tripping, characterized in that, Includes the following steps: In response to the detection of an over-tripping of the upstream magnetically controlled circuit breaker, the fault current data recorded by the magnetically controlled circuit breakers of each outgoing branch under the jurisdiction of the upstream magnetically controlled circuit breaker during the fault period are obtained. Based on the fault current data of each outgoing branch, calculate the proportion of the fault current of each outgoing branch to the sum of the fault currents of all outgoing branches. The fault current ratio of each outgoing branch is compared with a preset threshold. When the fault current ratio of a certain outgoing branch is greater than or equal to the preset threshold, the outgoing branch is determined to be a faulty branch. Send a trip command to the magnetically controlled circuit breaker of the faulty branch to isolate the faulty branch; After confirming that the faulty branch has been successfully isolated, the upstream magnetic circuit breaker is controlled to perform a reclosing operation to restore power supply to the non-faulty branch.

2. The self-healing method for cascading tripping as described in claim 1, characterized in that, The step of calculating the percentage of the fault current of each outgoing branch relative to the sum of the fault currents of all outgoing branches based on the fault current data of each outgoing branch includes: Extract the instantaneous fault current value of each outgoing branch at the moment of fault occurrence from the fault current data recorded by the magnetically controlled circuit breakers of each outgoing branch. , , ..., ,in n This represents the total number of outgoing branches; Align the instantaneous fault current values ​​of each outgoing branch to ensure that the current sampling time of all branches corresponds to the same fault time section. Calculate the sum of the instantaneous values ​​of the fault current in all outgoing branches: Calculate the instantaneous fault current value for each outgoing branch. The ratio of the fault current to the total current gives the proportion of fault current in that branch: ； Output the percentage of fault current for each outgoing branch. , , ..., .

3. The self-healing method for cascading tripping as described in claim 2, characterized in that, The step of comparing the fault current ratio of each outgoing branch with a preset threshold, and determining that the outgoing branch is a faulty branch when the fault current ratio of a certain outgoing branch is greater than or equal to the preset threshold, includes: Obtain a pre-set fault determination threshold K, wherein the value of K ranges from 0.6 to 0.9; The fault current percentage of each outgoing branch is calculated sequentially. Compare with the threshold K; If there exists an outgoing branch m that satisfies If so, then mark the branch as a candidate faulty branch; Verify the uniqueness of the candidate faulty branch: if only one outgoing branch satisfies... If multiple outgoing branches simultaneously meet the condition, then the branch is directly determined to be a faulty branch; Then select The branch with the largest value is designated as the faulty branch, and this abnormal situation is reported as an alarm message. Output fault branch identifier.

4. The self-healing method for cascading tripping as described in claim 3, characterized in that, The step of sending a trip command to the magnetically controlled circuit breaker of the faulty branch to isolate the faulty branch includes: Based on the fault branch identifier, generate a tripping control command for the magnetic circuit breaker of that branch; The station-side IoT unit sends a tripping command to the magnetic circuit breaker of the faulty branch and records the time of command transmission. The switch position status of the magnetic circuit breaker in the faulty branch is collected after a preset time window Δt. Determine whether the collected switch position status is in the open position: If the circuit is in the tripped position, confirm that the faulty branch has been successfully isolated and record the isolation completion time. ; If the circuit breaker is not in the open position, the isolation is determined to have failed. The delay preset time window steps are repeated. If the circuit breaker is still not successfully opened after repeating the preset number of times, the subsequent reclosing operation is blocked and an operation and maintenance alarm is reported. Output the isolation success flag and the isolation completion time. .

5. The self-healing method for cascading tripping as described in claim 4, characterized in that, After confirming that the faulty branch has been successfully isolated, the upstream magnetic circuit breaker is controlled to perform a reclosing operation to restore power supply to the non-faulty branch. This process includes the following sub-steps: At the time of completion of quarantine Based on this, the delayed reclosing waiting time Ensure that the faulty branch has been completely disconnected; Before the delay ends, collect the current of the branch box busbar. and judge Is it less than the rated current? : like < If so, reclosing is permitted; like ≥ If the busbar is found to be in a state of continuous fault, reclosing should be suspended and an anomaly should be reported. The station-end IoT unit sends a closing command to the upper-level magnetically controlled circuit breaker to control it to perform a reclosing operation.

6. The self-healing method for cascading tripping as described in claim 5, characterized in that, Also includes: After sending the closing command, a preset time window is delayed to collect the switch position status of the upstream magnetically controlled circuit breaker and bus voltage and current data. Determine if reclosing was successful: If the upstream magnetic circuit breaker is in the closed position, and the bus voltage recovers to more than 90% of the rated voltage, and the current of the non-faulty branch is normal, then the reclosing is considered successful and the self-healing process is completed. If the upstream magnetically controlled circuit breaker fails to close successfully, or if a fault current is detected again after closing, it is determined that the reclosing is a permanent fault. The upstream circuit breaker should be immediately locked, and reclosing should be prohibited. The incident should be reported to the maintenance personnel for on-site handling.

7. A magnetically controlled cable branch box, characterized in that, The method for self-healing over-tripping as described in any one of claims 1-6 includes: SMC insulated enclosure (1), with built-in busbars and acrylic insulated protective plate (3); The low-voltage magnetic circuit breaker (2) is connected to the station-end IoT unit (5) for detecting electrical parameters in the enclosure (1), including the incoming magnetic circuit breaker and the outgoing magnetic circuit breaker. The incoming magnetic circuit breaker is connected in series with the outgoing magnetic circuit breaker via a busbar. The environmental monitoring module is connected to the station IoT unit (5) for detecting environmental data inside the box (1); The station-end IoT unit (5) is connected to the low-voltage magnetic circuit breaker (2) and the environmental monitoring module. It is used to receive the electrical parameters and environmental data, determine whether there is a fault, and upload them to the cloud. The generator vehicle quick interface (4) is connected to the busbar and is used to quickly connect to the power supply from the emergency generator vehicle in an emergency. It consists of four quick connectors, which correspond to the three phases A, B, and C and the neutral line N, respectively. The cloud is used to receive fault signals from the station IoT unit (5) and issue a cut-off command. When the fault is recovered, a recovery command is issued. The Bluetooth communication module is built into the station-end IoT unit (5) and the low-voltage magnetic circuit breaker (2). The Bluetooth communication module is connected to an external handheld terminal signal and is used by the handheld terminal to remotely send instructions through the Bluetooth communication module to control the opening and closing of the low-voltage magnetic circuit breaker (2).

8. The magnetically controlled cable branch box as described in claim 7, characterized in that, The low-voltage magnetic circuit breaker (2) includes an incoming magnetic circuit breaker and several outgoing magnetic circuit breakers. The several outgoing magnetic circuit breakers are connected in parallel, and the incoming magnetic circuit breaker and the several outgoing magnetic circuit breakers are connected in series.

9. The magnetically controlled cable branch box as described in claim 7, characterized in that, The environmental monitoring module integrates a temperature and humidity sensor, a smoke sensor, a water immersion sensor, and a door magnetic sensor. The environmental data includes the temperature, humidity, door magnetic status, water immersion, and smoke concentration inside the enclosure (1).

10. The magnetically controlled cable branch box as described in claim 9, characterized in that, An integrated temperature and humidity sensor (6), smoke sensor, water immersion sensor and door magnetic sensor are installed on the top of the cabinet (1); The generator car quick interface (4) is located above the low-voltage magnetic circuit breaker (2), and the station-end IoT unit (5) is located above the low-voltage magnetic circuit breaker (2); The box (1) is provided with a partition (7), which is an L-shaped plate, and the partition (7) is located between the station IoT unit (5) and the generator car quick interface (4); The guard plate (3) is located between the low-voltage magnetic circuit breaker (2) and the generator car quick interface (4). The guard plate (3) and the partition plate (7) are vertically distributed, and the height of the guard plate (3) is lower than that of the partition plate (7).

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