A distribution box facilitating safe maintenance and a control method thereof

Abstract

The application provides a distribution box convenient for safe maintenance and a control method thereof. Through full electronic design without mechanical moving parts, the application realizes active discharge of residual charge before maintenance, sound prewarning in a live state, graded prewarning of human body approach, automatic power-off, microsecond-level identification of fault arc and tripping, significantly improves the safety, reliability and convenience of the maintenance operation of the distribution box, and is suitable for intelligent transformation of various low-voltage distribution boxes.

Description

Technical Field

[0001] This invention relates to the field of distribution box technology, and specifically to a distribution box and its control method that facilitate safe maintenance. Background Technology

[0002] As the final stage equipment in a power distribution system, distribution boxes are widely used in industrial, commercial, and residential power distribution, undertaking the critical tasks of power distribution, control, and protection. During routine maintenance and troubleshooting, maintenance personnel frequently need to open the box doors to inspect, replace, or repair internal electrical components such as circuit breakers, contactors, busbars, and terminals. However, existing distribution boxes have many shortcomings in terms of maintenance safety, and electric shock accidents during maintenance occur frequently, seriously threatening personal safety.

[0003] First, even if the upstream circuit breaker has been disconnected, residual charge remains in the cables and electrical components inside the distribution box due to distributed capacitance. Especially with long cables or numerous parallel circuits, the residual voltage can reach hundreds of volts. If maintenance personnel touch the lines or components without fully discharging the residual charge, they will suffer electric shock. Second, distribution boxes often employ multi-circuit power supply designs. When maintenance personnel are repairing a specific circuit, adjacent circuits may still be energized. Due to the compact space and dense component layout inside the box, maintenance personnel's arms or metal tools can easily touch adjacent energized terminals or busbars, causing electric shock. Third, during maintenance, improper operation speed or contact oxidation can easily generate electric arcs when disconnecting or connecting circuits. Electric arcs, accompanied by high temperatures and intense light, can not only burn operators but also cause fires or damage equipment insulation, expanding the scope of the accident.

[0004] To address the aforementioned issues, several solutions have been proposed in existing technologies. For example, some distribution boxes use mechanical limit switches between the box door and the box body to cut off the main circuit power when the door is opened. However, limit switches are contact components, and after long-term use, contact oxidation and spring fatigue can lead to unreliable operation and fail to solve the problem of residual charge. Another example is the installation of leakage current devices (RCDs) and arc fault detectors in some distribution boxes; however, these are passive protection measures that only respond after an accident, and by the time the protective devices activate, the person has often already suffered an electric shock. Yet another existing technology uses arc-extinguishing grids for arc segmentation, but these grids have limited lifespan and only extinguish arcs within the switching equipment, failing to address the risk of accidental activation during maintenance. Furthermore, some solutions use protective covers and electromagnetic locks to physically isolate live parts, but these solutions involve numerous mechanical components, complex structures, and large space requirements. After long-term use, they are prone to jamming and wear, and are difficult to retrofit into existing distribution boxes, limiting their widespread application.

[0005] Therefore, there is an urgent need for a distribution box and its control method that facilitates safe maintenance. Through a fully electronic design without mechanical moving parts, it is possible to fundamentally solve problems such as residual charge, accidental contact with live wires, and electric arc injuries during maintenance operations, thereby improving the safety and convenience of maintenance. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a power distribution box and its control method that are easy to maintain safely.

[0007] The technical solution adopted by this invention is as follows: The first aspect of this invention provides a distribution box that facilitates safe maintenance, comprising a box body and electrical components disposed within the box body, the electrical components having terminals, and further comprising: The residual charge active discharge module is connected between each circuit of the distribution box and the protective ground. It includes a solid-state switch and a discharge resistor, and is equipped with a non-contact voltage detection unit for detecting the residual voltage of each circuit and outputting the first detection signal. The live state early warning module includes a wideband electric field sensor and a buzzer. The wideband electric field sensor is used to sense the power frequency electric field inside the box and output a second detection signal. The buzzer is used to issue an audible warning based on the second detection signal. The anti-accidental touch proximity warning module includes a capacitive proximity sensor array and a solid-state relay. The capacitive proximity sensor array is arranged around each of the terminals to detect the capacitance change when a human body or tool approaches each of the terminals and output a third detection signal. The solid-state relay is connected in series in each circuit to receive a power-off signal and cut off the power supply of the corresponding circuit. The fault arc detection and protection module includes a differential optical sensor for detecting arc light signals and outputting a fourth detection signal, and a solid-state circuit breaker for cutting off the circuit. The differential optical sensor includes an ultraviolet phototube and a visible phototube. The central controller is connected to the residual charge active discharge module, the live state early warning module, the anti-accidental contact proximity early warning module, and the fault arc detection and protection module, respectively. It receives the first detection signal, the second detection signal, the third detection signal, and the fourth detection signal, and controls the on / off state of the solid-state switch according to the first detection signal, controls the on / off state of the solid-state relay according to the third detection signal, and controls the on / off state of the solid-state circuit breaker according to the fourth detection signal.

[0008] Preferably, in the residual charge active discharge module, the solid-state switch is a bidirectional thyristor or SiC MOSFET, and the non-contact voltage detection unit is a capacitive voltage divider probe; when the central controller detects that the residual voltage is higher than the safety threshold in the maintenance mode, it triggers the solid-state switch to conduct and discharge the charge.

[0009] Preferably, the live state warning module further includes a supercapacitor energy storage unit for maintaining short-term power supply when the incoming line current is too low; the frequency of the buzzer's alert tone is positively correlated with the electric field strength.

[0010] Preferably, the capacitive proximity sensor array is a microstrip electrode printed on a flexible circuit board; the central controller collects the third detection signal of each electrode in real time to obtain the electrode-to-ground capacitance value and establishes a background capacitance diagram. When the capacitance change exceeds a first threshold, an early warning signal is output. When it exceeds a second threshold, the power supply of the corresponding circuit is cut off through the solid-state relay; the central controller also adjusts the response level according to the capacitance change rate.

[0011] Preferably, in the fault arc detection and protection module, the central controller calculates the rate of change of luminous flux dΦ / dt. When the light intensity exceeds the threshold, dΦ / dt exceeds the rate of change threshold, and the duration exceeds the set value, it is determined to be a fault arc, and the solid-state circuit breaker is triggered.

[0012] A second aspect of the present invention provides a control method for the above-mentioned distribution box, comprising the following steps: S1: Detect the status of the maintenance mode switch. If it is in maintenance mode, enter the safety protection process. S2: The residual voltage of each circuit is measured by a non-contact voltage detection unit. If it is higher than the first voltage threshold, the residual charge active discharge module is triggered until the voltage is lower than the second voltage threshold. S3: Activate the live state early warning module to continuously monitor the power frequency electric field inside the box. If there is an electric field, the buzzer will sound an alarm. S4: Activate the anti-accidental touch proximity warning module, scan the capacitance value of the capacitive proximity sensor array in real time, judge the degree of proximity based on the amount and rate of change of capacitance, and output visual and audible warnings or automatically power off. S5: Activate the fault arc detection module to analyze the ultraviolet-visible differential signal and the rate of change of luminous flux in real time. If a fault arc is detected, the solid-state circuit breaker will be immediately triggered to trip.

[0013] Preferably, in step S4, when the capacitance change ΔC exceeds the first threshold ΔC1 and the capacitance change rate dC / dt is less than the first rate threshold, it is determined to be a normal approach, and only a warning is issued; when ΔC exceeds ΔC1 and dC / dt is greater than the first rate threshold, it is determined to be a rapid intrusion, and the power is immediately cut off; when ΔC exceeds the second threshold ΔC2, the power is cut off unconditionally.

[0014] Preferably, in step S5, the luminous flux change rate threshold is automatically adjusted according to the background light intensity, and adaptive filtering is used to eliminate the influence of slow changes in ambient light.

[0015] The beneficial effects of the present invention are as follows: The present invention adopts a fully electronic design with no mechanical moving parts, which results in high reliability, fast response speed, strong environmental adaptability, and greatly facilitates maintenance operations; The residual charge active discharge module uses solid-state switches and non-contact detection to completely eliminate contact adhesion and arcing hazards, ensuring that the circuit is completely de-energized before maintenance. The live status early warning module utilizes non-contact induction of power frequency electric field, requiring no direct electrical connection, and features zero power consumption standby, allowing maintenance personnel to quickly determine the safety status. The anti-accidental touch proximity warning module is the first to apply capacitive proximity sensing and rate of change detection to the anti-accidental touch scenario of the distribution box, realizing graded response. It can not only avoid frequent power outages from interfering with normal operation, but also provide emergency protection against accidental rapid intrusion, significantly improving maintenance safety. The fault arc detection module uses ultraviolet-visible light differential and luminous flux change rate as dual criteria, which can accurately distinguish between normal switching arc and fault arc in microseconds. Combined with solid-state circuit breaker, it can achieve ultra-fast tripping and suppress arc energy to an extremely low level. This invention can be easily installed in existing distribution boxes without structural modifications, and has broad market application prospects. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0017] Figure 1 This is a schematic diagram of the modular structure of the distribution box provided in an embodiment of the present invention; Figure 2 This is a flowchart illustrating the distribution box control method provided in an embodiment of the present invention. In the diagram, 1 is the central controller; 2 is the residual charge active discharge module; 3 is the live state early warning module; 4 is the accidental contact proximity early warning module; and 5 is the fault arc detection and protection module. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0019] like Figure 1As shown, the first aspect of this invention provides a distribution box that facilitates safe maintenance, including a box body and electrical components disposed within the box body. The electrical components have terminals, such as the incoming and outgoing terminals of a circuit breaker, and the connection terminals of a busbar. The distribution box also includes a central controller 1, a residual charge active discharge module 2, a live state early warning module 3, an anti-accidental contact proximity early warning module 4, and a fault arc detection and protection module 5.

[0020] The central controller 1 uses an STM32F4 series microcontroller with built-in multi-channel ADCs and high-speed comparators, serving as the core processing unit for the safety protection of the entire distribution box. The central controller 1 is connected to the residual charge active discharge module 2, the live status early warning module 3, the accidental contact prevention proximity early warning module 4, and the fault arc detection and protection module 5.

[0021] The residual charge active discharge module 2 is connected between the incoming lines L1, L2, L3 and the outgoing circuits of the distribution box and the protective ground PE. This module includes a solid-state switch and a discharge resistor, which are connected in series between each circuit and the protective ground. The solid-state switch receives control signals from the central controller 1 to turn the discharge path on or off; the discharge resistor releases the residual charge stored in the circuit to the protective ground when the solid-state switch is on. The module also includes a non-contact voltage detection unit to detect the residual voltage in each circuit and output a first detection signal to the central controller 1.

[0022] The live state warning module 3 includes a wideband electric field sensor and a buzzer. The wideband electric field sensor is installed in the center of the inner wall of the enclosure door to sense the power frequency electric field inside the enclosure and output a second detection signal; the buzzer is fixed next to the sensor to issue an audible warning based on the second detection signal.

[0023] The anti-accidental touch proximity warning module 4 includes a capacitive proximity sensor array and solid-state relays. The capacitive proximity sensor array consists of multiple flexible circuit board electrodes arranged around each terminal, used to detect capacitance changes when a person or tool approaches each terminal and output a third detection signal. Solid-state relays are connected in series in each circuit, used to receive power-off signals from the central controller 1 and cut off the power to the corresponding circuit. This module is equipped with corresponding LED indicators to provide visual warnings based on the tiered warning signals output by the central controller 1.

[0024] The fault arc detection and protection module 5 includes a differential optical sensor composed of an ultraviolet phototube and a visible phototube, as well as a solid-state circuit breaker. The differential optical sensor is installed near the busbar and the outgoing terminals of the circuit breaker to detect arc light signals and output a fourth detection signal. The solid-state circuit breaker is connected in series in the main incoming line or each outgoing circuit to receive trip signals from the central controller 1 and disconnect the circuit.

[0025] The central controller 1 receives a first detection signal, a second detection signal, a third detection signal, and a fourth detection signal. Based on the first detection signal, the central controller 1 outputs a control signal to the solid-state switch to control its on / off state (achieving residual charge discharge). Based on the third detection signal, it outputs a tiered warning signal and a power-off signal, and also outputs a power-off signal to the solid-state relay to control its on / off state (achieving tiered warning against accidental contact and automatic power-off). Based on the fourth detection signal, it outputs a trip signal to the solid-state circuit breaker to control its on / off state (achieving arc fault protection). These modules work together to achieve the safe maintenance function of the distribution box.

[0026] As a specific implementation, taking a single-phase AC circuit as an example, in the residual charge active discharge module 2, a solid-state switch and a discharge resistor are connected in series between the L line and the PE line. The solid-state switch is a bidirectional thyristor TR1 (model BTA16-600B), and the discharge resistor R1 is 10kΩ / 5W. The non-contact voltage detection unit uses a capacitive voltage divider probe, composed of capacitors C1 and C2. The probe is installed close to the outer insulation layer of the cable and is not directly electrically connected to the primary circuit. The induced voltage is amplified by operational amplifier U1 and sent as the first detection signal to the ADC pin of the central controller 1.

[0027] When maintenance personnel close the maintenance mode switch SW1 outside the enclosure (i.e., enter maintenance mode), the central controller 1 determines the effective value of the residual voltage in each circuit based on the first detection signal. If the residual voltage is higher than the safety threshold (e.g., 36V), the central controller 1 outputs a conduction control signal to the bidirectional thyristor TR1—triggering TR1 to conduct via the optocoupler MOC3063, and the residual charge is released to the protective ground PE through the discharge resistor R1. During the discharge process, the central controller 1 continuously monitors the first detection signal. When the residual voltage drops below the safety voltage (e.g., 12V), the central controller 1 outputs a shutdown control signal to TR1, automatically turning off the bidirectional thyristor TR1, and the discharge path is cut off.

[0028] For the DC circuit, the solid-state switch uses SiC MOSFET (e.g., C3M0065090J) and adds soft-start PWM control to limit the rate of rise of the discharge current di / dt < 5A / μs, so as to avoid damage to the device by the instantaneous discharge current surge.

[0029] As a specific implementation, the live state early warning module 3 includes a broadband electric field sensor, a buzzer, and a supercapacitor energy storage unit. The broadband electric field sensor 31 has a bandwidth of 50Hz~1MHz, and its sensing electrode is a copper foil plate with an area of ​​about 10cm², which is installed in the center of the inner wall of the enclosure door to maximize the sensing of the power frequency electric field throughout the enclosure.

[0030] The second detection signal output by the sensor is first amplified by a preamplifier (gain approximately 40dB), and then processed by a precision rectifier and comparator. When the power frequency electric field strength represented by the second detection signal exceeds a set threshold (e.g., 20V / m), the comparator outputs a high level to drive a buzzer to emit intermittent beeping sounds ("beep-beep"). The frequency of the beeping sound is positively correlated with the amplitude of the second detection signal—the stronger the electric field, the higher the frequency of the buzzer's sound, allowing maintenance personnel to perceive the degree of electrical charge through changes in sound.

[0031] The supercapacitor energy storage unit (5F / 5.5V) is connected in the sensor power supply circuit. When the main power supply line of the distribution box is energized but the load current is extremely small, the inductive power supply is insufficient to directly drive the circuit. The supercapacitor can provide short-term power supply (lasting about 10 seconds) at the initial stage of the maintenance mode activation, ensuring that the sensor can work normally and output the second detection signal at the moment of startup. When the buzzer is completely silent, it indicates that there is no power frequency electric field inside the box (i.e., all circuits are de-energized), and maintenance personnel can visually confirm the safety status based on this.

[0032] In one specific implementation, microstrip electrodes made of flexible circuit boards are attached around each terminal block inside the distribution box. The electrodes are 10mm × 20mm in size and spaced 15mm apart. A distributed capacitance (approximately 2~5pF) is formed between each electrode and ground. Each electrode is connected to a capacitance-to-digital converter (e.g., an FDC2214 chip) of the central controller 1 via a coaxial cable. This converter continuously detects the capacitance value of the electrode to ground and outputs it to the central controller 1 in the form of a third detection signal.

[0033] Solid-state relays (such as Panasonic AQH2223) are connected in series in each circuit, and their control terminals are connected to the I / O port of the central controller 1.

[0034] The central controller 1 calculates the capacitance to ground of each electrode in real time based on the third detection signal and executes graded early warning and power-off control. Upon initial power-on, the central controller 1 collects the capacitance to ground values ​​of each electrode as the reference background capacitance map C0. During operation, the reference is updated slowly with a time constant of 30 seconds, while median filtering (window length of 5 sampling points) is used to eliminate transient electromagnetic interference.

[0035] The hierarchical control logic is as follows: When the capacitance change ΔC = C - C0 exceeds the first threshold ΔC1 (e.g., 0.5pF) and the capacitance change rate dC / dt is less than the first rate threshold (e.g., 80pF / s), the central controller 1 determines that a human or tool is normally approaching the terminal and outputs a graded warning signal—the corresponding LED indicator changes from green to yellow, the speaker emits a 1kHz intermittent variable tone (the frequency increases as ΔC increases), and the power is not cut off so that maintenance personnel can work normally.

[0036] When ΔC exceeds ΔC1 and dC / dt is greater than the first rate threshold, the central controller 1 determines that it is a rapid intrusion (e.g., an accidental fall or tool falling off causing a rapid contact with a live part), and immediately outputs a power-off signal to the solid-state relay of the circuit. After receiving the power-off signal, the solid-state relay cuts off the power supply to the corresponding circuit, and at the same time, the LED indicator turns red and flashes, and the speaker emits a 2kHz urgent alarm sound.

[0037] When ΔC exceeds the second threshold ΔC2 (e.g., 3.0pF), regardless of dC / dt, the central controller 1 unconditionally outputs a power-off signal to the solid-state relay and locks it. Power can only be restored after manual reset by maintenance personnel.

[0038] If the hand leaves the area (the capacitor returns to within ±0.2pF of the reference value) and there is a 2-second delay, power will be automatically restored if it is the first case; otherwise, manual reset by maintenance personnel is required. To prevent reference drift caused by slow changes in ambient temperature and humidity, the central controller 1 pauses background updates after performing a power-off action and re-establishes the reference after manual reset.

[0039] In one specific implementation, an ultraviolet (UV) photodiode R2868 and a visible light photodiode BPW34 are installed 5 cm above the busbar, forming a differential optical sensor. The UV photodiode is sensitive to ultraviolet light (wavelength 200~280nm) generated by an electric arc, while the visible light photodiode is sensitive to ambient light and ordinary light. The output signals of the two tubes are amplified by a transimpedance amplifier (gain 10kΩ) and then fed into a differential amplifier. The differentially amplified signal is used as the fourth detection signal and sent to a high-speed comparator (LMV7219), the external interrupt input of the central controller 1, and the fast ADC channel.

[0040] The reference voltage of the high-speed comparator is set to 300mV (corresponding to a light intensity threshold of 10W / m²). When the amplitude of the differential signal exceeds the reference voltage, the rising edge of the comparator output triggers an external interrupt for the central controller 1. After responding to the interrupt, the central controller 1 continuously samples the fourth detection signal through its built-in fast ADC (sampling rate 1MSPS) and calculates the rate of change of luminous flux over time, dΦ / dt.

[0041] The fault arc determination logic is as follows: When the following three conditions are met simultaneously, the central controller 1 determines that it is a real fault arc: (1) the absolute value of light intensity exceeds 10W / m²; (2) the rate of change of light flux dΦ / dt exceeds 2×10³ lm / s; (3) the duration of the above state exceeds 50μs (to filter out nanosecond-level spike noise).

[0042] Once a fault arc is detected, the central controller 1 immediately outputs a trip signal to the solid-state circuit breaker. Upon receiving the trip signal, the solid-state circuit breaker (using an IXYS IXFN200N07T MOSFET module) completely shuts off the fault circuit within 80μs. If the fourth detection signal exhibits a low rate of change of luminous flux (dΦ / dt < 1 × 10³ lm / s), even if the light intensity briefly exceeds the threshold, the central controller 1 will still classify it as a normal switching operation arc and will not output a trip signal, thus avoiding false tripping.

[0043] like Figure 2 As shown, a second aspect of this invention provides a control method for a distribution box that facilitates safe maintenance, as described above. After maintenance personnel turn the maintenance mode switch outside the box door to the "ON" position, the central controller 1 executes the safety protection control method according to the following steps: Step S1: When the central controller 1 detects the maintenance mode signal (switch closed), it first resets all alarm states, including clearing the lock flags of each module, turning off the alarm indicator lights, and initializing the parameters of each sensor.

[0044] Step S2: The central controller 1 acquires the first detection signal through the non-contact voltage detection unit of each circuit and measures the residual voltage of each circuit sequentially. If the residual voltage of a certain circuit is higher than the first voltage threshold (e.g., 36V), the corresponding residual charge active discharge module 2 is activated—the central controller 1 outputs a conduction control signal to the solid-state switch of that circuit, so that the residual charge is released to the protective ground PE through the discharge resistor. During the discharge process, the central controller 1 continuously monitors the voltage change through the first detection signal until the residual voltage of all circuits is lower than the second voltage threshold (e.g., 12V). Then, it outputs a shutdown control signal to all solid-state switches, and at the same time, the buzzer emits a slow "beep-beep-beep" prompt sound to indicate that the discharge is complete. After the prompt sound stops, the next stage begins.

[0045] Step S3: The central controller 1 activates the live state early warning module 3, which acquires the second detection signal through a wideband electric field sensor and continuously monitors the power frequency electric field inside the enclosure. If the second detection signal indicates the presence of a power frequency electric field inside the enclosure and its intensity is greater than a set threshold (e.g., 20V / m), a buzzer emits a rapid "beep-beep" warning sound; otherwise, the buzzer remains silent. This step continues throughout the entire maintenance cycle.

[0046] Step S4: The central controller 1 activates the anti-accidental touch proximity warning module 4, acquires the third detection signal through the capacitive proximity sensor array, and scans the capacitance value of each electrode in real time. It then makes a graded judgment based on the capacitance change ΔC and the capacitance change rate dC / dt. When ΔC exceeds the first threshold ΔC1 (e.g., 0.5pF) and dC / dt is less than the first rate threshold (e.g., 80pF / s), the central controller 1 determines it as normal proximity (the maintenance personnel consciously and slowly reach out), and only outputs a visual warning (LED changes from green to yellow) and an audible warning (the speaker emits a 1kHz intermittent tone), without outputting a power-off signal, so that the maintenance personnel can work normally; When ΔC exceeds ΔC1 and dC / dt is greater than the first rate threshold, the central controller 1 determines that it is a rapid intrusion (e.g., an accidental fall or tool falling off causing a rapid contact with a live part), and immediately outputs a power-off signal to the solid-state relay of the circuit to cut off the power supply. At the same time, the LED turns red and flashes, and the speaker emits a 2kHz urgent alarm sound. When ΔC exceeds the second threshold ΔC2 (e.g., 3.0pF), regardless of dC / dt, the central controller 1 unconditionally outputs a power-off signal to the solid-state relay and locks it, requiring manual reset.

[0047] If the hand leaves the area (the capacitor returns to within ±0.2pF of the reference value) and there is a 2-second delay, power will be automatically restored if it is the first case; otherwise, manual reset by maintenance personnel is required if it is the second or third case.

[0048] Step S5: The central controller 1 activates the fault arc detection and protection module 5, acquiring the fourth detection signal through the ultraviolet-visible differential optical sensor, and analyzing the ultraviolet-visible differential signal and the rate of change of luminous flux dΦ / dt in real time. The threshold for the rate of change of luminous flux is not a fixed value, but is automatically adjusted according to the background light intensity—the stronger the background light, the higher the threshold, to prevent false judgments caused by sudden changes in ambient light. Simultaneously, the central controller 1 has a built-in adaptive filter that tracks the slow changes in ambient light with a time constant of 10 seconds and subtracts them from the fourth detection signal. When a genuine fault arc is detected, the central controller 1 immediately outputs a trip signal to the solid-state circuit breaker and locks the alarm state. Maintenance personnel must manually reset the circuit after confirming on-site safety.

[0049] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A distribution box for easy and safe maintenance, comprising a box body and electrical components disposed within the box body, wherein the electrical components have terminals, characterized in that, Also includes: The residual charge active discharge module is connected between each circuit of the distribution box and the protective ground. It includes a solid-state switch and a discharge resistor, and is equipped with a non-contact voltage detection unit for detecting the residual voltage of each circuit and outputting the first detection signal. The live state early warning module includes a wideband electric field sensor and a buzzer. The wideband electric field sensor is used to sense the power frequency electric field inside the box and output a second detection signal. The buzzer is used to issue an audible warning based on the second detection signal. The anti-accidental touch proximity warning module includes a capacitive proximity sensor array and a solid-state relay. The capacitive proximity sensor array is arranged around each of the terminals to detect the capacitance change when a human body or tool approaches each of the terminals and output a third detection signal. The solid-state relay is connected in series in each circuit to receive a power-off signal and cut off the power supply of the corresponding circuit. The fault arc detection and protection module includes a differential optical sensor for detecting arc light signals and outputting a fourth detection signal, and a solid-state circuit breaker for cutting off the circuit. The differential optical sensor includes an ultraviolet phototube and a visible phototube. The central controller is connected to the residual charge active discharge module, the live state early warning module, the anti-accidental contact proximity early warning module, and the fault arc detection and protection module, respectively. It receives the first detection signal, the second detection signal, the third detection signal, and the fourth detection signal, and controls the on / off state of the solid-state switch according to the first detection signal, controls the on / off state of the solid-state relay according to the third detection signal, and controls the on / off state of the solid-state circuit breaker according to the fourth detection signal.

2. The distribution box for easy and safe maintenance according to claim 1, characterized in that, In the residual charge active discharge module, the solid-state switch is a bidirectional thyristor or SiC MOSFET, and the non-contact voltage detection unit is a capacitive voltage divider probe; when the central controller detects that the residual voltage is higher than the safety threshold in the maintenance mode, it triggers the solid-state switch to conduct and discharge the charge.

3. The distribution box for easy and safe maintenance according to claim 1, characterized in that, The live state warning module also includes a supercapacitor energy storage unit, which is used to maintain short-term power supply when the incoming current is too low; the frequency of the buzzer's alert tone is positively correlated with the electric field strength.

4. The distribution box for easy and safe maintenance according to claim 1, characterized in that, The capacitive proximity sensor array consists of microstrip electrodes printed on a flexible circuit board. The central controller acquires the third detection signal of each electrode in real time to obtain the electrode-to-ground capacitance value and establishes a background capacitance diagram. When the capacitance change exceeds the first threshold, an early warning signal is output. When it exceeds the second threshold, the power supply of the corresponding circuit is cut off through the solid-state relay. The central controller also adjusts the response level according to the capacitance change rate.

5. The distribution box for easy and safe maintenance according to claim 1, characterized in that, In the fault arc detection and protection module, the central controller calculates the rate of change of luminous flux dΦ / dt. When the light intensity exceeds the threshold, dΦ / dt exceeds the rate of change threshold, and the duration exceeds the set value, it is determined to be a fault arc and triggers the solid-state circuit breaker.

6. A control method based on the distribution box according to any one of claims 1-5, characterized in that... Includes the following steps: S1: Detect the status of the maintenance mode switch. If it is in maintenance mode, enter the safety protection process. S2: The residual voltage of each circuit is measured by a non-contact voltage detection unit. If it is higher than the first voltage threshold, the residual charge active discharge module is triggered until the voltage is lower than the second voltage threshold. S3: Activate the live state early warning module to continuously monitor the power frequency electric field inside the box. If there is an electric field, the buzzer will sound an alarm. S4: Activate the anti-accidental touch proximity warning module, scan the capacitance value of the capacitive proximity sensor array in real time, judge the degree of proximity based on the amount and rate of change of capacitance, and output visual and audible warnings or automatically power off. S5: Activate the fault arc detection module to analyze the ultraviolet-visible differential signal and the rate of change of luminous flux in real time. If a fault arc is detected, the solid-state circuit breaker will be immediately triggered to trip.

7. The control method according to claim 6, characterized in that, In step S4, when the capacitance change ΔC exceeds the first threshold ΔC1 and the capacitance change rate dC / dt is less than the first rate threshold, it is determined to be a normal approach, and only a warning is issued; when ΔC exceeds ΔC1 and dC / dt is greater than the first rate threshold, it is determined to be a rapid intrusion, and the power is immediately cut off; when ΔC exceeds the second threshold ΔC2, the power is cut off unconditionally.

8. The control method according to claim 6, characterized in that, In step S5, the luminous flux change rate threshold is automatically adjusted according to the background light intensity, and adaptive filtering is used to eliminate the influence of slow changes in ambient light.

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