Intelligent safety discharging device for low-voltage reactive power compensation cabinet and control method thereof

Abstract

The application discloses an intelligent safety discharging device for a low-voltage reactive compensation cabinet and a control method thereof, and relates to the technical field of power electronics and low-voltage power distribution equipment.The discharging device is composed of a surge suppression module, a voltage sampling module, an isolation power supply, an MCU controller, a relay matrix, a state output module and a ladder resistance network.The application sets the ladder resistance network composed of multiple levels of resistance, and combines the voltage sampling module to realize real-time isolation sampling of the capacitor voltage, dynamically switches the discharging path according to the voltage change in the discharging process, and realizes the cooperative control of fast discharging in the high-voltage stage and fine discharging in the low-voltage stage.The discharging completion state is judged through continuous monitoring and a delay anti-shake mechanism, so that the misjudgment caused by transient interference is avoided.Meanwhile, the MCU controller is provided with an anti-interference algorithm and combined with multiple protection strategies such as overvoltage, overtemperature and sampling abnormality, so that the operation stability and reliability of the device in the complex electromagnetic environment are enhanced.

Description

Technical Field

[0001] This invention relates to the field of power electronics and low-voltage power distribution equipment technology, and in particular to an intelligent safe discharge device and its control method for a low-voltage reactive power compensation cabinet. Background Technology

[0002] Low-voltage reactive power compensation cabinets are widely used in industrial power distribution systems, public building power distribution systems, and commercial power applications. They are used to compensate for reactive power caused by inductive loads, thereby improving the power factor, reducing line losses, and enhancing energy utilization efficiency. Low-voltage reactive power compensation cabinets typically achieve reactive power compensation by switching parallel capacitor banks.

[0003] During the operation or shutdown of a low-voltage reactive power compensation cabinet, the capacitor bank will still store high-voltage electrical energy after power is cut off. If the residual voltage of the capacitor is not released to a safe range in a timely and reliable manner, it can easily pose a risk of electric shock to maintenance personnel or damage subsequent switching operations and related electrical components. Therefore, safe and controllable discharge of capacitors is an essential safety measure in low-voltage reactive power compensation cabinets.

[0004] Existing low-voltage reactive power compensation cabinets often employ fixed resistor discharge or simple relay control. On the one hand, fixed resistor discharge struggles to balance rapid discharge during high-voltage phases with precise control during low-voltage phases, easily leading to excessively long discharge times or severe resistor overheating. On the other hand, some solutions lack real-time monitoring and tiered control of capacitor voltage changes, making the discharge process unadjustable and lacking sufficient safety redundancy. Furthermore, existing discharge devices are mostly based on single-state indication or passive discharge, lacking clear distinction and visual output of discharge, safety, and fault states. When abnormal conditions such as overvoltage, overtemperature, or sampling anomalies occur, it is difficult to identify them promptly and take effective protective measures, posing certain safety hazards. Simultaneously, some discharge control schemes lack sufficient anti-interference capabilities in complex electromagnetic environments, easily affected by harmonics or transient interference, leading to misjudgments in the discharge control logic.

[0005] Therefore, there is an urgent need for an intelligent safety discharge device and its control method suitable for low-voltage reactive power compensation cabinets, which can monitor capacitor voltage in real time, dynamically adjust the discharge path according to different voltage ranges, reduce device stress while ensuring rapid discharge, and have complete status indication and fault protection capabilities, so as to improve the operational safety and reliability of low-voltage reactive power compensation cabinets. Summary of the Invention

[0006] In view of the above-mentioned problems, the present invention is proposed.

[0007] Therefore, the present invention provides an intelligent safe discharge device and its control method for low-voltage reactive power compensation cabinets to solve the problems of uncontrollable discharge process, lack of graded discharge and fine control, and unclear identification of discharge state and safety state in the prior art.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0009] In a first aspect, embodiments of the present invention provide an intelligent safety discharge device for a low-voltage reactive power compensation cabinet. The discharge device consists of a surge suppression module, a voltage sampling module, an isolation power supply, an MCU controller, a relay matrix, a status output module, and a stepped resistor network.

[0010] As a preferred embodiment of the intelligent safe discharge device for low-voltage reactive power compensation cabinet described in this invention, the surge suppression module includes a TVS diode, a PTC thermistor, and a varistor connected in parallel, wherein the clamping voltage of the TVS diode is 440V and the response time is ≤1ns.

[0011] As a preferred embodiment of the intelligent safe discharge device for low-voltage reactive power compensation cabinet described in this invention, the voltage sampling module includes a series-connected voltage divider resistor network and an isolation amplifier, wherein the ratio of the voltage divider resistor network to the isolation amplifier is 1000:1, and the voltage division ratio error of the voltage sampling module is ≤±0.1%, and the isolation withstand voltage is ≥3750Vrms.

[0012] As a preferred embodiment of the intelligent safe discharge device for low-voltage reactive power compensation cabinet described in this invention, the MCU controller includes a main control chip, a clock circuit and a reset circuit, and the MCU controller has a built-in anti-interference algorithm, which includes median filtering and 50Hz harmonic rejection.

[0013] As a preferred embodiment of the intelligent safe discharge device for low-voltage reactive power compensation cabinet described in this invention, the relay matrix includes three power relays, and the coils of the power relays are independently controlled by the MCU controller through a drive circuit.

[0014] As a preferred embodiment of the intelligent safe discharge device for low-voltage reactive power compensation cabinet described in this invention, the stepped resistor network includes a first-stage resistor, a second-stage resistor, and a third-stage resistor.

[0015] Specifically, when the sampling voltage is below 300V, the relay matrix is ​​controlled to switch to the second-level resistor after a set delay anti-jitter time; when the sampling voltage is below 100V, the relay matrix is ​​controlled to switch to the third-level resistor, and the delay anti-jitter time is 200ms.

[0016] The MCU controller also adjusts the switching strategy of the relay matrix based on the detected temperature of the stepped resistor network. When the temperature exceeds a preset threshold, it controls the switching to a high-resistance level or limits the continuous connection time of the low-resistance resistor.

[0017] As a preferred embodiment of the intelligent safe discharge device for low-voltage reactive power compensation cabinet described in this invention, the status output module includes a dual-color LED indicator, a buzzer alarm, and an OLED display screen electrically connected to the MCU controller.

[0018] In the discharge state, the MCU controller controls the dual-color LED indicator to display the first color and drives the OLED display to display the real-time voltage value; in the safe state, the MCU controller controls the dual-color LED indicator to display the second color and controls the OLED display to display safety warning information; in the fault state, the MCU controller controls the dual-color LED indicator to flash and controls the OLED display to display the corresponding fault code.

[0019] Secondly, embodiments of the present invention provide an intelligent safe discharge control method for a low-voltage reactive power compensation cabinet, comprising:

[0020] After the discharge device is started, it enters the standby state. The voltage sampling module in the discharge device samples the capacitor voltage. When the sampled voltage is greater than the preset safety threshold of 50V, the discharge device exits the standby state and enters the discharge state.

[0021] During the discharge state, the relay matrix is ​​controlled by the MCU controller in the discharge device to dynamically connect at least one resistor level in the stepped resistor network to participate in the discharge.

[0022] During the discharge process, when the sampling voltage drops below the first switching threshold of 300V, the MCU controller controls the relay matrix to switch the discharge path to the second-stage resistor after a set delay anti-jitter time; when the sampling voltage drops below the second switching threshold of 100V, the controller controls the relay matrix to switch the discharge path to the third-stage resistor.

[0023] When the sampling voltage drops to no higher than 50V, the discharge device starts continuous monitoring and timing, and makes a joint judgment on the safety status by combining the temperature detection results and the stability of the sampling signal; when the sampling voltage remains no higher than 50V, the temperature is within the safe range, and the sampling signal has no abnormal fluctuations and continues for a preset time of 5s, the discharge device exits the discharge state and enters the safe state.

[0024] The discharge device maintains the discharge output off under safe conditions and automatically disconnects the discharge output after a preset time of 30 seconds.

[0025] When the sampling voltage is greater than 600V, the detection temperature is greater than 120℃, or an ADC abnormality occurs, the discharge device exits the current state and enters the fault state, and performs the corresponding protection processing; after the fault conditions are cleared, the discharge device exits the fault state and re-enters the standby state.

[0026] Thirdly, embodiments of the present invention provide a computer device, including a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program instructions are executed by the processor, they implement the steps of an intelligent safe discharge device for a low-voltage reactive power compensation cabinet as described in the first aspect of the present invention.

[0027] Fourthly, embodiments of the present invention provide a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program instructions are executed by a processor, they implement the steps of an intelligent safe discharge device for a low-voltage reactive power compensation cabinet as described in the first aspect of the present invention.

[0028] The beneficial effects of this invention are as follows: By setting up a stepped resistor network composed of multi-level resistors and combining it with a voltage sampling module to perform real-time isolated sampling of the capacitor voltage, the invention dynamically switches the discharge path according to voltage changes during the discharge process, achieving coordinated control of rapid discharge in the high-voltage stage and fine discharge in the low-voltage stage. This effectively reduces device thermal shock and safety risks while ensuring discharge efficiency. Continuous monitoring and a delay-based anti-jitter mechanism determine the discharge completion status, avoiding misjudgments caused by transient interference and improving the accuracy of residual voltage assessment. Simultaneously, the MCU controller incorporates an anti-interference algorithm and combines multiple protection strategies such as overvoltage, overtemperature, and sampling anomaly protection to enhance the stability and reliability of the device in complex electromagnetic environments. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a main circuit topology diagram of an intelligent safe discharge device and its control method for a low-voltage reactive power compensation cabinet according to an embodiment of the present invention. Figure 2 This is a control flowchart of an intelligent safe discharge device and its control method for a low-voltage reactive power compensation cabinet according to an embodiment of the present invention. Figure 3 This is a flowchart illustrating the surge suppression module of an intelligent safe discharge device and its control method for a low-voltage reactive power compensation cabinet, according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the complete discharge process of an intelligent safety discharge device and its control method for a low-voltage reactive power compensation cabinet according to an embodiment of the present invention. Detailed Implementation

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0032] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0033] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0034] Example 1

[0035] Reference Figures 1-4 This is the first embodiment of the present invention. This embodiment provides an intelligent safety discharge device for a low-voltage reactive power compensation cabinet. The discharge device consists of a surge suppression module, a voltage sampling module, an isolation power supply, an MCU controller, a relay matrix, a status output module, and a stepped resistor network.

[0036] Specifically, the surge suppression module includes a TVS diode, a PTC thermistor, and a varistor connected in parallel. The TVS diode has a clamping voltage of 440V and a response time of ≤1ns, and is used to quickly clamp operational overvoltages and lightning surges in the initial stage of discharge.

[0037] Preferably, the PTC thermistor's resistance jumps to over 1kΩ when the current reaches 5A to limit abnormally large currents and achieve self-recovery protection; the varistor is used to absorb high-energy surges and works in conjunction with the TVS diode to improve the system's impact resistance.

[0038] Specifically, the voltage sampling module includes a series-connected voltage divider resistor network and an isolation amplifier, wherein the ratio of the voltage divider resistor network to the isolation amplifier is 1000:1, which is used to convert the 0-1000V high voltage signal into a 0-3.3V low voltage safety signal for the MCU controller to acquire.

[0039] Preferably, the voltage sampling module has a voltage division ratio error ≤ ±0.1% and an isolation withstand voltage ≥ 3750Vrms to ensure measurement accuracy and personal safety under high-voltage discharge conditions.

[0040] Specifically, the isolated power supply includes a DC-DC isolation module and a filter capacitor, which are used to provide stable isolated power supply for the MCU controller and peripheral circuits.

[0041] Preferably, the input voltage range of the isolation power supply is 4.5 to 5.5V, the output voltage is 5V, the output current is 200mA, and the isolation withstand voltage is 1500VDC, which is used to block ground loop interference and improve the anti-interference capability of the system.

[0042] Specifically, the MCU controller includes a main control chip, a clock circuit, and a reset circuit, used to execute discharge control logic, acquire voltage signals, and control the relay matrix and status output module.

[0043] Preferably, the MCU controller has a built-in anti-interference algorithm, which includes median filtering and 50Hz harmonic rejection, used to suppress power frequency fluctuations and transient interference, and improve the stability of relay switching determination.

[0044] Furthermore, the MCU controller acquires the output signal of the voltage sampling module through the ADC and calculates the actual voltage based on the sampled value. When the voltage is ≤50V and lasts for 5 seconds, it is determined to be in a safe state.

[0045] Furthermore, to improve discharge safety, this embodiment incorporates a temperature-resistance linkage control function into the MCU controller: the MCU controller collects temperature sensor data at the location of the resistor network in real time; when the detected temperature exceeds a set threshold (e.g., 120°C), the MCU controller automatically adjusts the switching logic of the relay matrix, switching the discharge path to a high-resistance resistor stage to limit the discharge current and reduce temperature rise, thereby preventing resistor overheating and damage. When the temperature returns to a safe range, the MCU controller can restore the original stepped resistor switching logic, achieving dynamic temperature protection and discharge linkage.

[0046] Furthermore, this embodiment employs a multi-parameter joint determination method in determining the safety status: when determining the discharge safety status, the MCU controller not only considers that the capacitor voltage is continuously below 50V, but also takes into account the temperature sensor data and the stability of the sampling signal; only when the voltage is ≤50V, the temperature is within the safe range, and the sampling signal has no abnormal fluctuations and continues for a preset time (e.g., 5s), does the MCU controller determine it to be in a safe state and trigger the output action in the safe state; this joint determination method effectively avoids the misjudgment that may be caused by a single voltage determination, and improves the safety reliability and intelligence level of the discharge device.

[0047] Specifically, the relay matrix includes three power relays and corresponding drive circuits, and the coils of the power relays are independently controlled by the MCU controller through the drive circuits.

[0048] Preferably, the power relay has a contact capacity of 50A and 480VAC, and an operating time of 10ms, and is used to switch the discharge path of the stepped resistor network in different voltage ranges to achieve graded discharge control.

[0049] Specifically, the stepped resistor network includes a first-stage resistor, a second-stage resistor, and a third-stage resistor, which respectively constitute three-stage discharge paths.

[0050] The first-stage resistor is used to withstand the inrush current under high residual voltage conditions in the initial stage of discharge; the second-stage resistor is used for current-limiting discharge in the voltage range of 100 to 300V; and the third-stage resistor is used for fine discharge in the voltage range below 100V.

[0051] Preferably, the switching threshold of the stepped resistor network is set to 300V and 100V, and the switching action is delayed by 200ms to prevent the relay from frequently engaging due to voltage fluctuations.

[0052] Specifically, the status output module includes a dual-color LED indicator, a buzzer alarm, and an OLED display screen, all electrically connected to the MCU controller.

[0053] In the discharge state, the MCU controller controls the dual-color LED indicator to display the first color and drives the OLED display to display the real-time voltage value; in the safe state, the MCU controller controls the dual-color LED indicator to display the second color and controls the OLED display to display safety warning information; in the fault state, the MCU controller controls the dual-color LED indicator to flash and controls the OLED display to display the corresponding fault code.

[0054] In this embodiment, the discharge device enters a standby state after startup, and enters a discharge state when the capacitor voltage is detected to be greater than 50V. During the discharge process, the stepped resistor network is dynamically switched according to the real-time sampled voltage. When the voltage is continuously lower than 50V for a preset time, it enters a safe state. In the event of overvoltage, overheating or abnormal sampling, it enters a fault state and performs protection processing.

[0055] This embodiment also provides an intelligent safe discharge control method for low-voltage reactive power compensation cabinets, including:

[0056] After the discharge device is started, it enters the standby state. The voltage sampling module in the discharge device samples the capacitor voltage. When the sampled voltage is greater than the preset safety threshold of 50V, the discharge device exits the standby state and enters the discharge state.

[0057] During the discharge state, the relay matrix is ​​controlled by the MCU controller in the discharge device to dynamically connect at least one resistor level in the stepped resistor network to participate in the discharge.

[0058] During the discharge process, when the sampling voltage drops below the first switching threshold of 300V, the MCU controller controls the relay matrix to switch the discharge path to the second-stage resistor after a set delay anti-jitter time; when the sampling voltage drops below the second switching threshold of 100V, the controller controls the relay matrix to switch the discharge path to the third-stage resistor.

[0059] When the sampling voltage drops to no higher than 50V, the discharge device starts continuous monitoring and timing, and makes a joint judgment on the safety status by combining the temperature detection results and the stability of the sampling signal; when the sampling voltage remains no higher than 50V, the temperature is within the safe range, and the sampling signal has no abnormal fluctuations and continues for a preset time of 5s, the discharge device exits the discharge state and enters the safe state.

[0060] The discharge device maintains the discharge output off under safe conditions and automatically disconnects the discharge output after a preset time of 30 seconds.

[0061] When the sampling voltage is greater than 600V, the detection temperature is greater than 120℃, or an ADC abnormality occurs, the discharge device exits the current state and enters the fault state, and performs the corresponding protection processing; after the fault conditions are cleared, the discharge device exits the fault state and re-enters the standby state.

[0062] This embodiment also provides a computer device applicable to an intelligent safety discharge device for a low-voltage reactive power compensation cabinet, including a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to realize the intelligent safety discharge device for a low-voltage reactive power compensation cabinet as proposed in the above embodiment.

[0063] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0064] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements an intelligent safe discharge device for a low-voltage reactive power compensation cabinet as proposed in the above embodiment.

[0065] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An intelligent safety discharge device for a low-voltage reactive power compensation cabinet, characterized in that, The discharge device consists of a surge suppression module, a voltage sampling module, an isolation power supply, an MCU controller, a relay matrix, a status output module, and a stepped resistor network.

2. The intelligent safety discharge device for a low-voltage reactive power compensation cabinet as described in claim 1, characterized in that, The surge suppression module includes a TVS diode, a PTC thermistor, and a varistor connected in parallel. The TVS diode has a clamping voltage of 440V and a response time of ≤1ns.

3. The intelligent safety discharge device for a low-voltage reactive power compensation cabinet as described in claim 1, characterized in that, The voltage sampling module includes a voltage divider resistor network and an isolation amplifier connected in series, wherein the ratio of the voltage divider resistor network to the isolation amplifier is 1000:1, and the voltage division ratio error of the voltage sampling module is ≤±0.1% and the isolation withstand voltage is ≥3750Vrms.

4. The intelligent safety discharge device for a low-voltage reactive power compensation cabinet as described in claim 1, characterized in that, The MCU controller includes a main control chip, a clock circuit, and a reset circuit. The MCU controller has a built-in anti-interference algorithm, which includes median filtering and 50Hz harmonic rejection.

5. The intelligent safety discharge device for a low-voltage reactive power compensation cabinet as described in claim 1, characterized in that, The relay matrix includes three power relays, and the coils of the power relays are independently controlled by the MCU controller through a drive circuit.

6. The intelligent safety discharge device for a low-voltage reactive power compensation cabinet as described in claim 1, characterized in that, The stepped resistor network includes a first-stage resistor, a second-stage resistor, and a third-stage resistor; Specifically, when the sampling voltage is below 300V, the relay matrix is ​​controlled to switch to the second-level resistor after a set delay anti-jitter time; when the sampling voltage is below 100V, the relay matrix is ​​controlled to switch to the third-level resistor, and the delay anti-jitter time is 200ms. The MCU controller also adjusts the switching strategy of the relay matrix based on the detected temperature of the stepped resistor network. When the temperature exceeds a preset threshold, it controls the switching to a high-resistance level or limits the continuous connection time of the low-resistance resistor.

7. The intelligent safety discharge device for a low-voltage reactive power compensation cabinet as described in claim 1, characterized in that, The status output module includes a dual-color LED indicator, a buzzer alarm, and an OLED display, all electrically connected to the MCU controller. In the discharge state, the MCU controller controls the dual-color LED indicator to display the first color and drives the OLED display to display the real-time voltage value; In a safe state, the MCU controller controls the dual-color LED indicator to display the second color and controls the OLED display to display safety warning information; In the event of a fault, the MCU controller controls the dual-color LED indicator to flash and controls the OLED display to show the corresponding fault code.

8. A method for intelligent safe discharge control in a low-voltage reactive power compensation cabinet, characterized in that, include: After the discharge device is started, it enters the standby state. The voltage sampling module in the discharge device samples the capacitor voltage. When the sampled voltage is greater than the preset safety threshold of 50V, the discharge device exits the standby state and enters the discharge state. During the discharge state, the relay matrix is ​​controlled by the MCU controller in the discharge device to dynamically connect at least one resistor level in the stepped resistor network to participate in the discharge. During the discharge process, when the sampling voltage drops below the first switching threshold of 300V, the MCU controller controls the relay matrix to switch the discharge path to the second-stage resistor after a set delay anti-jitter time; when the sampling voltage drops below the second switching threshold of 100V, the controller controls the relay matrix to switch the discharge path to the third-stage resistor. When the sampling voltage drops to no higher than 50V, the discharge device starts continuous monitoring and timing, and makes a joint judgment on the safety status by combining the temperature detection results and the stability of the sampling signal; when the sampling voltage remains no higher than 50V, the temperature is within the safe range, and the sampling signal has no abnormal fluctuations and continues for a preset time of 5s, the discharge device exits the discharge state and enters the safe state. The discharge device maintains the discharge output off under safe conditions and automatically disconnects the discharge output after a preset time of 30 seconds. When the sampling voltage is greater than 600V, the detection temperature is greater than 120℃, or an ADC abnormality occurs, the discharge device exits the current state and enters the fault state, and performs the corresponding protection processing; after the fault conditions are cleared, the discharge device exits the fault state and re-enters the standby state.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the intelligent safe discharge device for a low-voltage reactive power compensation cabinet as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the intelligent safe discharge device for a low-voltage reactive power compensation cabinet as described in any one of claims 1 to 7.

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