Discharging method and system of networking SVG (static var generator) based on super capacitor

Abstract

The invention discloses a super-capacitor-based discharging method and a super-capacitor-based discharging system for a networked SVG (static var generator), and relates to the technical field of discharging methods for networked SVGs. According to a discharging instruction, a controllable constant-power discharging mode of a first stage of networked SVG equipment is triggered; triggering the booster circuit to work based on the reduction of the voltage of the super capacitor, maintaining the constant voltage of the bus, and enabling the network construction type SVG equipment to enter a constant-power discharge mode of a second stage; according to the invention, the network-forming type SVG equipment feeds back energy to the power grid at a constant power until the voltage of the super capacitor is reduced to be below the safe voltage, and the network-forming type SVG equipment is in the power-reducing discharge mode of the final discharge stage, so that the multi-stage discharge control of the network-forming type SVG equipment is realized, and therefore, in the maintenance event of the network-forming type SVG equipment, the maintenance efficiency of the network-forming type SVG equipment is improved. A corresponding abnormal circuit is determined based on anomaly detection of the network-building type SVG equipment, and a maintenance area of the network-building type SVG equipment is determined according to the abnormal circuit and key parameters of the network-building type SVG equipment in the discharging process.

Description

Technical Field

[0001] This invention relates to the technical field of discharge methods for grid-connected SVG, and more particularly to a discharge method and system for grid-connected SVG based on supercapacitors. Background Technology

[0002] With the development of technology, cascaded grid-connected SVG is widely used in fields such as new energy grid connection and industrial power distribution. Its core consists of multiple cascaded H-bridge power units. Each unit is usually equipped with a supercapacitor as an energy storage medium. When the equipment is maintained, the main power supply needs to be cut off. However, due to the energy storage characteristics of supercapacitors, high voltage energy still remains inside after the power is cut off. If it is not completely reduced, the conventional discharge method in the existing technology uses a fixed resistance value to reduce the resistance for discharge. However, it is impossible to achieve multi-stage discharge control of grid-connected SVG equipment, resulting in poor discharge effect of grid-connected SVG equipment. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a discharge method and system for a supercapacitor-based grid SVG.

[0004] This invention provides a discharge method for a supercapacitor-based grid SVG, comprising: The maintenance status of the grid-type SVG device is determined based on multiple working data of the grid-type SVG device, and a discharge command is output. Based on the discharge command, the first stage of the controllable constant power discharge mode of the grid-type SVG device is triggered to feed energy back to the grid. The voltage drop of the supercapacitor triggers the operation of the boost circuit and maintains a constant bus voltage, allowing the grid-type SVG equipment to enter the second stage of constant power discharge mode. When the grid-type SVG device is in the second stage of constant power discharge mode, the grid-type SVG device feeds energy back to the grid at a constant power until the voltage of the supercapacitor drops below the safe voltage. At this time, the grid-type SVG device is in the final discharge stage of reduced power discharge mode. When the grid-type SVG device is in the reduced power discharge mode during the final discharge stage, the safety interlock mechanism of the grid-type SVG device is activated, and the maintenance events of the grid-type SVG device are collected. In maintenance events of network-type SVG devices, the corresponding abnormal circuit is determined based on the abnormal detection of the network-type SVG device, and the maintenance area of ​​the network-type SVG device is determined based on the abnormal circuit and the key parameters of the network-type SVG device during the discharge process.

[0005] This invention provides a discharge system for a supercapacitor-based grid SVG, which is applied to the aforementioned discharge method for a supercapacitor-based grid SVG. The discharge system for the supercapacitor-based grid SVG includes: The first-stage module is used to determine the maintenance status of the grid-type SVG device based on multiple working data of the grid-type SVG device, and output a discharge command. Based on the discharge command, the first-stage controllable constant power discharge mode of the grid-type SVG device is triggered to feed energy back to the grid. The second-stage module is used to trigger the operation of the boost circuit based on the voltage drop of the supercapacitor and maintain the constant bus voltage, so that the grid-type SVG equipment enters the second-stage constant power discharge mode. The final discharge stage module is used when the grid-type SVG device is in the constant power discharge mode of the second stage. The grid-type SVG device feeds energy back to the grid at a constant power until the voltage of the supercapacitor drops below the safe voltage. At this time, the grid-type SVG device is in the reduced power discharge mode of the final discharge stage. The safety interlock module is used to activate the safety interlock mechanism of the grid-type SVG device when the grid-type SVG device is in the reduced power discharge mode during the final discharge stage, and to collect maintenance events of the grid-type SVG device. The maintenance module is used to determine the corresponding abnormal circuit based on the abnormal detection of the network-type SVG device during maintenance events, and to determine the maintenance area of ​​the network-type SVG device based on the abnormal circuit and the key parameters of the network-type SVG device during the discharge process.

[0006] Compared with the prior art, the beneficial effects of the present invention are: In this embodiment of the invention, the maintenance status of the grid-type SVG device is determined based on multiple operating data of the device, and a discharge command is output. This discharge command triggers the first stage of the controllable constant power discharge mode of the grid-type SVG device to feed energy back to the grid. The voltage drop of the supercapacitor triggers the operation of the boost circuit, maintaining a constant bus voltage, and the grid-type SVG device enters the second stage of the constant power discharge mode. While in the second stage of the constant power discharge mode, the grid-type SVG device feeds energy back to the grid at a constant power until the voltage of the supercapacitor drops below a safe voltage. At this point, the grid-type SVG device enters the final stage of the reduced power discharge mode. By sequentially introducing the first stage of the controllable constant power discharge mode, the second stage of the constant power discharge mode, and the final stage of the reduced power discharge mode, multi-stage discharge control of the grid-type SVG device is achieved, improving its discharge performance.

[0007] Therefore, when the grid-type SVG device is in the reduced power discharge mode during the final discharge stage, the safety interlock mechanism of the grid-type SVG device is activated, and maintenance events of the grid-type SVG device are collected. In the maintenance events of the grid-type SVG device, the corresponding abnormal circuit is determined based on the abnormal detection of the grid-type SVG device. The maintenance area of ​​the grid-type SVG device is determined according to the abnormal circuit and the key parameters of the grid-type SVG device during the discharge process. The safety interlock mechanism and maintenance events of the grid-type SVG device are introduced, and the overall consideration of abnormal circuit and key parameters of the grid-type SVG device during the discharge process is compatible. This improves the accuracy of the maintenance area of ​​the grid-type SVG device and improves the repair effect of the grid-type SVG device in a safe state. Attached Figure Description

[0008] Figure 1 This is a schematic flowchart of the discharge method of the supercapacitor-based grid SVG in an embodiment of the present invention; Figure 2 This is a flowchart illustrating step S11 in the discharge method of SVG based on supercapacitor network in an embodiment of the present invention. Figure 3 This is a flowchart illustrating step S12 in the discharge method of SVG based on supercapacitor network in an embodiment of the present invention. Figure 4 This is a flowchart illustrating step S13 in the discharge method of SVG based on supercapacitor network in an embodiment of the present invention. Figure 5 This is a flowchart illustrating step S14 of the discharge method for a supercapacitor-based grid SVG in an embodiment of the present invention. Figure 6 This is a flowchart illustrating step S15 in the discharge method of SVG based on supercapacitor network in an embodiment of the present invention. Figure 7 This is a schematic diagram of the structural composition of the discharge system of the supercapacitor-based grid SVG in an embodiment of the present invention; Figure 8 This is a schematic diagram of the network-type SVG device system architecture topology of the discharge method of the network-type SVG based on supercapacitor in an embodiment of the present invention. Detailed Implementation

[0009] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0010] Please see Figures 1 to 8 A discharge method for supercapacitor-based gridded SVG is proposed, applied to discharge scenarios of supercapacitor-based gridded SVG. The discharge method for supercapacitor-based gridded SVG includes: Step S11: Determine the maintenance status of the grid-type SVG device based on multiple working data of the grid-type SVG device, and output a discharge command. Trigger the first stage of the controllable constant power discharge mode of the grid-type SVG device according to the discharge command to feed energy back to the grid. Step S12: The boost circuit is triggered by the voltage drop of the supercapacitor, and the bus voltage is kept constant. The grid-type SVG device enters the second stage of constant power discharge mode. Step S13: When the grid-type SVG device is in the constant power discharge mode of the second stage, the grid-type SVG device feeds energy back to the grid at a constant power until the voltage of the supercapacitor drops below the safe voltage. At this time, the grid-type SVG device is in the reduced power discharge mode of the final discharge stage. Step S14: When the grid-type SVG device is in the reduced power discharge mode of the final discharge stage, activate the safety interlock mechanism of the grid-type SVG device and collect the maintenance events of the grid-type SVG device. Step S15: In the maintenance event of the network-type SVG device, the corresponding abnormal circuit is determined based on the abnormal detection of the network-type SVG device, and the maintenance area of ​​the network-type SVG device is determined according to the abnormal circuit and the key parameters of the network-type SVG device during the discharge process. refer to Figure 2 In step S11, the maintenance status of the grid-type SVG device is determined based on multiple working data of the grid-type SVG device, and a discharge command is output. Based on the discharge command, the first stage of the controllable constant power discharge mode of the grid-type SVG device is triggered to feed energy back to the grid. In the specific implementation of this invention, the specific steps are as follows: S111: Real-time monitoring of network-type SVG devices, collection of multiple working data of network-type SVG devices, and determination of the status of network-type SVG devices based on multiple working data and the working duration of the network-type SVG device model; S112: When the grid-type SVG device is in maintenance mode, the grid-type SVG device outputs a discharge command. The discharge content of the grid-type SVG device is determined by parsing the discharge command. The mode switching of the grid-type SVG device is triggered according to the discharge content of the grid-type SVG device. At this time, the grid-type SVG device is in controllable constant power discharge mode and performs the first stage of discharge. The discharge efficiency corresponding to the first stage is collected. The grid-type SVG device feeds back energy to the grid along the discharge efficiency.

[0011] In the embodiments of this application, the network-type SVG device is monitored in real time, and multiple working data of the network-type SVG device are collected. The status of the network-type SVG device is determined based on the multiple working data and the working time of the network-type SVG device model. This overall consideration of multiple working data and the working time of the network-type SVG device model ensures the accuracy of the status of the network-type SVG device.

[0012] At this time, the grid-type SVG equipment is monitored in real time, and multiple operating data of the grid-type SVG equipment are collected. These data include grid voltage, grid current, power factor, supercapacitor voltage, equipment temperature, and fault alarm signals. Grid voltage: The grid voltage value at the SVG equipment connection point is collected through a high-precision voltage sensor. Grid current: The input / output current of the SVG equipment is collected through a current transformer. Power factor: The power factor of the SVG equipment is calculated to evaluate its reactive power compensation effect on the grid. Supercapacitor voltage: The terminal voltage of the supercapacitor is collected through a voltage sensor to determine its energy storage status. Equipment temperature: The temperature of key internal components of the SVG equipment, such as power modules and capacitors, is collected through a temperature sensor. Fault alarm signals: The system monitors whether the equipment issues fault alarm signals, such as overvoltage, overcurrent, and overtemperature.

[0013] Based on the importance of the equipment and the stability requirements of the power grid, a reasonable data acquisition frequency is set. For example, the power grid voltage and current can be acquired once per second, while the equipment temperature can be acquired once per minute. The acquired data is stored in the local memory of the equipment and transmitted to the monitoring system in real time through a communication module (such as Ethernet or RS485).

[0014] Based on the collected working data, equipment model, and working duration, the equipment status is determined. Different models of SVG equipment have different design parameters and performance indicators. For example, the rated voltage of the supercapacitor in a certain model of SVG equipment is 1075V, and the rated capacity is 238kW·h. The working duration of the equipment will affect its performance and reliability. For example, equipment that has been working for a long time will experience problems such as capacitor aging and power module performance degradation. Normal state, warning state, and maintenance state are introduced. Under these conditions, the normal state is characterized by the following: grid voltage, current, power factor, and other parameters being within the normal range, equipment temperature being below the set threshold, supercapacitor voltage being within the rated range, and working duration not exceeding the maintenance cycle. The warning state is characterized by some parameters approaching the threshold, such as equipment temperature approaching the upper limit, or supercapacitor voltage slightly decreasing but not exceeding the safe range. The maintenance state is characterized by abnormal alarm signals, such as overvoltage, overcurrent, or supercapacitor voltage falling below the safe value, or working duration exceeding the maintenance cycle.

[0015] Meanwhile, grid voltage thresholds, equipment temperature thresholds, and supercapacitor voltage thresholds are introduced. The normal range of grid voltage is 35KV±10%, the upper limit of equipment internal temperature is 70℃, and the equipment has been running for more than 3000 hours since the last maintenance. For example, if the equipment temperature exceeds 70℃ and lasts for more than 5 minutes, it enters maintenance mode. The monitoring system displays the equipment status as "maintenance" and outputs a discharge command. Based on the judgment result, the equipment status information is output. For example, the monitoring system displays the equipment status as "normal", "warning", or "maintenance".

[0016] Furthermore, when the grid-type SVG device is in maintenance mode, it outputs a discharge command. The discharge content of the grid-type SVG device is determined based on the parsing of the discharge command. The mode switching of the grid-type SVG device is triggered based on the discharge content. At this time, the grid-type SVG device is in a controllable constant power discharge mode and performs the first stage of discharge. The discharge efficiency corresponding to the first stage is collected, and the grid-type SVG device feeds energy back to the grid along the discharge efficiency.

[0017] At this time, when the equipment status assessment module determines that the equipment is in maintenance status, a discharge command is triggered to generate. The discharge command should include the following key information: Discharge power: The discharge power is set according to the supercapacitor capacity of the equipment and the grid demand; Discharge time: The discharge time is calculated according to the remaining charge of the supercapacitor and the discharge power, for example, the expected discharge time is 1 hour; Discharge mode: The equipment is specified to enter the controllable constant power discharge mode.

[0018] The discharge command is parsed to determine the discharge content. After receiving the discharge command, the equipment's control system reads the key parameters in the command through the command parsing module. The parsing module extracts the discharge power, discharge time, and mode switching command and converts them into control signals that the equipment can execute. After receiving the discharge command, the control unit starts the mode switching program. The mode switching program switches the equipment from the normal operation mode to the controllable constant power discharge mode. During the switching process, it is necessary to ensure a smooth transition of the equipment and avoid sudden changes in current or voltage.

[0019] The equipment enters a controllable constant power discharge mode to perform the first stage of discharge and collects the discharge efficiency. At this time, in the controllable constant power discharge mode, the equipment feeds energy back to the grid at a power of 6000kW. By monitoring the grid voltage and current in real time, the output power of the equipment is ensured to be maintained at 6000kW. The discharge efficiency can be calculated using the following formula:

[0020] refer to Figure 3In step S12, the boost circuit is triggered by the drop in voltage of the supercapacitor and the bus voltage is kept constant, and the grid-type SVG device enters the second stage of constant power discharge mode. In the specific implementation of this invention, the specific steps are as follows: S121: Monitor the operation of the supercapacitor in real time and collect the current voltage of the supercapacitor. At the same time, collect the first set voltage and compare the first set voltage with the current voltage of the supercapacitor to determine the amount of voltage drop of the supercapacitor. S122: Collect the circuit diagram of the network-type SVG device, determine the corresponding boost circuit based on the voltage drop of the supercapacitor, the supercapacitor model and the circuit diagram of the network-type SVG device, and trigger the operation of the boost circuit. S123: During the operation of the boost circuit, the boost circuit maintains the DC bus voltage of the power unit H-bridge at a set constant value to maintain the constant bus voltage. At this time, the grid-type SVG device enters the second stage of constant power discharge mode.

[0021] In the embodiments of this application, the operation of the supercapacitor is monitored in real time, and the current voltage of the supercapacitor is collected. At the same time, a first set voltage is collected, and the voltage drop of the supercapacitor is determined by comparing the first set voltage with the current voltage of the supercapacitor. This approach takes into account the overall comparison between the first set voltage and the current voltage of the supercapacitor, ensuring the accuracy of the voltage drop of the supercapacitor.

[0022] At this time, the current voltage of the supercapacitor is acquired in real time. A high-precision voltage sensor is used to monitor the terminal voltage of the supercapacitor in real time, usually once per second, to ensure that voltage changes can be captured in a timely manner. The acquired voltage data is stored in the control system of the equipment for subsequent analysis. At the same time, a first set voltage is set to compare with the current voltage of the supercapacitor. The first set voltage is usually set as a threshold based on the rated voltage of the supercapacitor. For example, for a supercapacitor with a rated voltage of 1075V, the first set voltage is set to 700V. This threshold can be adjusted according to the actual operating conditions and safety requirements of the equipment, and the difference between the current voltage of the supercapacitor and the first set voltage is calculated.

[0023] Furthermore, the circuit diagram of the network-type SVG device is collected. Based on the voltage drop of the supercapacitor, the supercapacitor model, and the circuit diagram of the network-type SVG device, the corresponding boost circuit is determined and triggered. This process takes into account the overall factors of the voltage drop of the supercapacitor, the supercapacitor model, and the circuit diagram of the network-type SVG device, ensuring the accuracy of the corresponding boost circuit. At this point, the circuit topology of the SVG device, especially the relevant information of the boost circuit, should be obtained. The circuit diagram should describe the topology of the SVG device in detail, including the connection relationships of power units, H-bridges, supercapacitors, boost circuits, etc. The circuit diagram can be stored in the device's control system in the form of electronic documents (such as CAD drawings) or data sheets. Meanwhile, the SVG device adopts a cascaded H-bridge topology, with a supercapacitor connected to the DC side of each H-bridge. The boost circuit is distributed on the DC bus side of each H-bridge to boost the DC bus voltage when the voltage drops. The circuit diagram is shown in Table 1. Table 1 Circuit Layout Diagram

[0024] Optionally, the supercapacitor model is SC-100. Based on the circuit diagram, the boost circuits that need to be activated are Boost1, Boost2, and Boost3. After receiving the command, the boost circuits Boost1, Boost2, and Boost3 start working, with the goal of boosting the DC bus voltage to 680V. The boost circuits adjust the switching frequency and duty cycle to boost the supercapacitor voltage from 660V to 680V and maintain a constant bus voltage. By acquiring the circuit diagram of the SVG equipment, combined with the voltage drop change and model information of the supercapacitor, the boost circuits that need to be activated are determined and triggered. This process requires an accurate circuit diagram, accurate voltage monitoring, and a reliable control system to ensure that the equipment can promptly boost the bus voltage when the voltage drops, maintaining the stable operation of the equipment.

[0025] Therefore, during the operation of the boost circuit, the boost circuit maintains the DC bus voltage of the power unit H-bridge at a set constant value to maintain the constant bus voltage. At this time, the grid-type SVG device enters the second stage of constant power discharge mode, which introduces the grid-type SVG device into the second stage of constant power discharge mode.

[0026] At this point, the boost circuit needs to maintain the DC bus voltage of the power unit H-bridge at a set constant value. A target bus voltage value is set according to the equipment's design requirements. This value is typically close to the rated voltage of the supercapacitor or the first set voltage. The boost circuit adjusts the switching frequency and duty cycle to raise the voltage of the H-bridge bus capacitor to the target bus voltage. The boost circuit needs to monitor the bus voltage in real time and adjust the output through a feedback control mechanism to ensure the bus voltage is maintained at the set value. The boost circuit uses closed-loop feedback control, monitoring the bus voltage in real time through a voltage sensor and comparing it with the set value. If a deviation is detected between the detected bus voltage and the set value, the boost circuit adjusts the switching frequency and duty cycle to correct the voltage deviation. The equipment then feeds energy back to the grid at a set power. This power is usually preset according to the equipment design and grid requirements. The equipment's control system needs to monitor the grid voltage, current, and power factor in real time to ensure the equipment discharges at a constant power.

[0027] refer to Figure 4 In step S13, when the grid-type SVG device is in the constant power discharge mode of the second stage, the grid-type SVG device feeds energy back to the grid at a constant power until the voltage of the supercapacitor drops below the safe voltage. At this time, the grid-type SVG device is in the reduced power discharge mode of the final discharge stage. In the specific implementation of this invention, the specific steps are as follows: S131: Real-time monitoring of the second stage constant power discharge mode of the grid-type SVG device, acquisition of the corresponding constant power, the grid-type SVG device feeds energy back to the grid under constant power discharge operation, and acquisition of the voltage of the supercapacitor at different times; S132: Collect the safe voltage, compare the voltage of the supercapacitor at different times with the safe voltage, and mark the time points when the voltage of the supercapacitor drops below the safe voltage; S133: Based on the time node that triggers the control of the discharge operation of the grid-type SVG device, the grid-type SVG device is adjusted from the constant power discharge mode of the second stage to the reduced power discharge mode of the final discharge stage.

[0028] In the embodiments of this application, the constant power discharge mode of the second stage of the grid-type SVG device is monitored in real time, and the corresponding constant power is collected. The grid-type SVG device feeds energy back to the grid under constant power discharge operation, and the voltage of the supercapacitor at different times is collected, thus introducing the voltage of the supercapacitor at different times.

[0029] At this point, the SVG device's operating status in the second stage is monitored in real time to ensure it is in constant power discharge mode. A high-precision power sensor is installed to monitor the SVG device's output power in real time. The power sensor transmits the collected power data to a data acquisition system, which collects data at a certain frequency (e.g., once per second). The control system receives the power data from the data acquisition system and compares it with the set constant power to ensure the device operates in constant power mode. The device's control system needs to monitor the grid voltage, current, and power factor in real time to ensure the device discharges at a constant power. The control system adjusts the device's output power through a feedback control mechanism to ensure it remains at the set value. Simultaneously, a high-precision voltage sensor is used to periodically collect the supercapacitor's voltage, typically once per second, to ensure timely capture of voltage changes. The collected voltage data is stored in the device's control system for subsequent analysis.

[0030] Optionally, suppose we have a grid-connected SVG device, model SVG-100, with the following main parameters: supercapacitor rated voltage: 1075V; second-stage discharge power: 3000kW; real-time monitoring of the constant power discharge mode in the second stage; a high-precision power sensor installed at the device output, with an accuracy of ±0.5%, collects power data at a frequency of 1Hz, and removes high-frequency noise through a digital filtering algorithm; the control system receives the power data from the data acquisition system and compares it with the set constant power of 3000kW to ensure that the device operates in constant power mode. At this time, the device's set discharge power is 3000kW, and the power sensor monitors the power in real time as 3100kW. The control system adjusts the device output to maintain it at 3000kW, and the device feeds energy back to the grid at a power of 3000kW. The control system adjusts the device's output power by monitoring the grid parameters in real time to ensure that it is maintained at 3000kW. During the discharge process, the voltage of the supercapacitor is collected every second, and the voltage data table for the second stage is collected.

[0031] By monitoring the second-stage constant power discharge mode of the SVG device in real time, the corresponding constant power and the voltage of the supercapacitor are collected. This process requires high-precision power and voltage sensors, a reliable data acquisition system, and a real-time feedback control mechanism to ensure that the device operates safely and stably in constant power mode and to provide data support for subsequent voltage monitoring and mode switching.

[0032] Furthermore, a safe voltage is collected, and the voltage of the supercapacitor at different times is compared with the safe voltage. The time points when the voltage of the supercapacitor drops below the safe voltage are marked, thus introducing the time points when the voltage of the supercapacitor drops below the safe voltage.

[0033] At this point, a safe voltage is acquired and set. This safe voltage value is used to determine whether the supercapacitor voltage has dropped below the safe range. Based on the equipment's design requirements and safe operation standards, a safe voltage value is set. This value is typically lower than the supercapacitor's rated voltage to ensure the equipment operates within a safe range. The safe voltage value is stored in the equipment's control system for easy access. A high-precision voltage sensor periodically acquires the supercapacitor voltage, usually once per second, to ensure timely detection of voltage changes. The acquired voltage data is stored in the equipment's control system for subsequent analysis. The control system compares the acquired supercapacitor voltage with the safe voltage in real time. When the supercapacitor voltage drops below the safe voltage, the time point is recorded.

[0034] Therefore, based on the control of the discharge operation of the grid-type SVG device triggered by this time node, the grid-type SVG device is adjusted from the constant power discharge mode of the second stage to the reduced power discharge mode of the final discharge stage. At the same time, the controllable constant power discharge mode of the first stage, the constant power discharge mode of the second stage, and the reduced power discharge mode of the final discharge stage are introduced in sequence, realizing multi-stage discharge control of the grid-type SVG device and improving the discharge effect of the grid-type SVG device.

[0035] At this point, based on the marked time node (the time when the supercapacitor voltage drops below the safe voltage), the equipment's discharge operation control is triggered. The control system reads the marked time node (e.g., 40 seconds) and generates a control command accordingly, preparing to adjust the equipment's discharge mode. The equipment is switched from the constant power discharge mode of the second stage to the reduced power discharge mode of the final discharge stage. Based on the equipment's design requirements and safety operation standards, the target power for the final discharge stage is set. This power is typically lower than the power of the second stage. The control system sends a control signal to adjust the equipment's discharge power. Upon receiving the control signal, the equipment switches from the constant power discharge mode of the second stage to the reduced power discharge mode of the final discharge stage. During the final discharge stage, the equipment's operating status is continuously monitored to ensure safe operation in the reduced power mode. Power and voltage sensors continue to monitor the equipment's output power and the supercapacitor's voltage in real time. The control system adjusts the equipment's output power based on the real-time monitoring data.

[0036] Optionally, suppose we have a grid-connected SVG device, model SVG-100, with the following main parameters: supercapacitor rated voltage: 1075V; second-stage discharge power: 3000kW; final discharge stage power: 70kW; the control system reads the marked time node at 120 seconds. At 120 seconds, the control system generates a control command to prepare to adjust the discharge mode. At 120 seconds, the device switches from 3000kW to a reduced power discharge mode of 70kW. The device continues to feed energy back to the grid at a power of 70kW. In the final discharge stage, the device performs natural discharge at a power of 70kW. The control system adjusts the output power of the device by monitoring the grid parameters in real time to ensure that the power is gradually reduced.

[0037] refer to Figure 5 In step S14, when the grid-type SVG device is in the reduced power discharge mode of the final discharge stage, the safety interlock mechanism of the grid-type SVG device is activated, and the maintenance event of the grid-type SVG device is collected. In the specific implementation of this invention, the specific steps are as follows: S141: The power reduction discharge mode in the final discharge stage of the real-time grid-type SVG device monitors the real-time voltage of the supercapacitor and maintains the real-time voltage of the supercapacitor below the safe voltage. S142: Perform security management on the network-type SVG device, and determine the security management path of the network-type SVG device based on the security management signal of the network-type SVG device. Based on the security management path and the circuit distribution diagram of the network-type SVG device, determine the security interlock mechanism to activate the security interlock mechanism of the network-type SVG device. The interlock mechanism ensures that the network-type SVG device cannot be started by accident before maintenance through dual hardware and software control. S143: Under the control of the safety interlock mechanism, the network-type SVG device is activated and multiple maintenance data of the network-type SVG device are collected. Based on the multiple maintenance data, the status of the network-type SVG device and the safety interlock mechanism, the maintenance event of the network-type SVG device is determined.

[0038] In the embodiments of this application, the power reduction discharge mode of the final discharge stage of the real-time grid-type SVG device monitors the real-time voltage of the supercapacitor and maintains the real-time voltage of the stage capacitor below the safe voltage, thus introducing a method to maintain the real-time voltage of the stage capacitor below the safe voltage.

[0039] At this point, the operating status of the SVG device during the final discharge stage is monitored in real time to ensure it is in a reduced-power discharge mode. A high-precision power sensor is used to monitor the output power of the SVG device in real time, typically once per second, to ensure timely capture of power changes. The control system receives the power data from the data acquisition system and compares it with the set power discharge to ensure the device operates in a reduced-power mode. A high-precision voltage sensor is used to periodically collect the voltage of the supercapacitor, typically once per second, to ensure timely capture of voltage changes. The collected voltage data is stored in the device's control system for subsequent analysis. Based on the real-time monitored voltage data, the control system adjusts the device's discharge power to ensure the supercapacitor voltage remains below the safe voltage, which is typically set according to the device's design requirements and safe operating standards.

[0040] Optionally, assuming we have a network-type SVG device, model SVG-100, with the following main parameters: supercapacitor rated voltage: 1075V; final discharge stage power: 70kW; a high-precision power sensor installed at the device output, with an accuracy of ±0.5%, the device's set discharge power is 70kW, and the power sensor monitors a real-time power of 70.2kW. The control system adjusts the device output to reduce it to 70kW. Further, safety management is implemented for the network-type SVG device, and a safety management path is determined based on the device's safety management signals. A safety interlock mechanism is then determined based on this path and the circuit diagram activating the network-type SVG device. This interlock mechanism, controlled by both hardware and software, ensures that the network-type SVG device cannot be accidentally started before maintenance. It considers both the safety management path and the circuit diagram activating the network-type SVG device, guaranteeing the accuracy of the safety interlock mechanism.

[0041] At this point, based on the equipment's operating status and safety requirements, a safety control signal is generated. When the equipment enters maintenance mode or detects an anomaly, the control system generates a safety control signal. This signal contains safety operation instructions that the equipment needs to execute, such as cutting off the power supply or locking the equipment. The equipment's circuit diagram details the connection relationships of various components, including the H-bridge, boost circuit, and supercapacitor. Based on the safety control signal and circuit diagram, the required safety operation path is determined. For example, if locking the equipment is required, the path includes cutting off the H-bridge power supply and locking the boost circuit. Based on the safety control path, a safety interlock mechanism is activated to ensure that the equipment cannot be accidentally started before maintenance. Hardware control: critical circuits are cut off via physical switches or relays to ensure the equipment cannot be started. Software control: the equipment's start command is locked by the control system to ensure the equipment cannot be accidentally started. This dual hardware and software control ensures the equipment's safety.

[0042] Therefore, under the control of the safety interlock mechanism, the activation of the network-type SVG device is managed by collecting multiple maintenance data of the network-type SVG device. Based on the multiple maintenance data, the status of the network-type SVG device, and the safety interlock mechanism, the maintenance events of the network-type SVG device are determined. This approach takes into account the overall consideration of multiple maintenance data, the status of the network-type SVG device, and the safety interlock mechanism, ensuring the accuracy of the maintenance events of the network-type SVG device.

[0043] At this time, with the safety interlock mechanism activated, multiple key maintenance data of the equipment are collected, including but not limited to: supercapacitor voltage: monitoring the real-time voltage of the supercapacitor; equipment temperature: monitoring the temperature of key internal components; discharge power: monitoring the real-time discharge power of the equipment; grid parameters: monitoring grid voltage, current, and power factor; fault alarm signals: monitoring whether the equipment issues a fault alarm signal. The collected data is stored in the equipment's control system for subsequent analysis. The collected maintenance data is analyzed to identify abnormal or maintenance-required signals. Combined with the current status of the equipment (such as running time, historical maintenance records, etc.), the overall health status of the equipment is assessed to confirm whether the safety interlock mechanism is working properly, ensuring that the equipment cannot be accidentally started before maintenance. Based on the analysis results, specific maintenance events are determined, such as: overheating: if the equipment temperature exceeds the safety threshold, cooling maintenance is required; undervoltage: if the supercapacitor voltage is below the safety voltage, the capacitor status needs to be checked; fault alarm: if the equipment issues a fault alarm signal, fault investigation is required.

[0044] Specifically, suppose we have a grid-type SVG device, model SVG-100, with the following main parameters: supercapacitor rated voltage: 1075V; final discharge stage power: 70kW; upper limit of device temperature: 65℃; high-precision voltage sensors, temperature sensors, and power sensors are used to collect the device's operating data, with a data acquisition frequency of once per second to ensure timely capture of data changes. Analysis of the collected maintenance data reveals that the device temperature reaches 63℃ at 55 seconds, approaching the upper limit of the device's safe operating temperature (65℃). The supercapacitor voltage is below the safe voltage, the discharge power remains at the set value, the grid parameters are normal, there are no fault alarm signals, the device has been running for over 3000 hours, and it is nearing its maintenance cycle. Historical maintenance records show that the device underwent cooling maintenance due to high temperature, confirming that the safety interlock mechanism is activated and the device cannot be started by accidental operation. Based on the analysis results, the maintenance event is determined: the device needs cooling maintenance to prevent further temperature increases.

[0045] refer to Figure 6In step S15, in the maintenance event of the network-type SVG device, the corresponding abnormal circuit is determined based on the abnormal detection of the network-type SVG device, and the maintenance area of ​​the network-type SVG device is determined according to the abnormal circuit and the key parameters of the network-type SVG device during the discharge process. In the specific implementation of this invention, the specific steps are as follows: S151: Monitor maintenance events of network-type SVG devices in real time, perform anomaly detection on network-type SVG devices, determine the corresponding abnormal areas based on the anomaly detection of network-type SVG devices, and determine the corresponding abnormal circuits based on the abnormal areas and the circuit distribution diagram of network-type SVG devices. S152: Collect key parameters of the grid-type SVG device during the discharge process, determine multiple sub-maintenance areas based on the key parameters of the grid-type SVG device during the discharge process and the distribution location of abnormal circuits, and determine the maintenance area of ​​the grid-type SVG device according to the multiple sub-maintenance areas and the circuit distribution diagram of the grid-type SVG device.

[0046] In the embodiments of this application, maintenance events of the network-type SVG device are monitored in real time, and anomaly detection is performed on the network-type SVG device. The corresponding abnormal area is determined based on the anomaly detection of the network-type SVG device, and the corresponding abnormal circuit is determined based on the abnormal area and the circuit distribution diagram of the network-type SVG device. This approach takes into account both the abnormal area and the circuit distribution diagram of the network-type SVG device, ensuring the accuracy of the corresponding abnormal circuit.

[0047] At this point, the equipment's operating status is monitored in real time, and maintenance events are recorded and analyzed. The equipment's monitoring system collects operational data in real time, including key parameters such as voltage, current, temperature, and power, typically once per second, to ensure timely capture of data changes. The collected data is stored in the equipment's control system for subsequent analysis. Based on the equipment's design requirements and safety operation standards, thresholds for key parameters are set. The equipment is divided into multiple areas based on its physical structure and functional modules, such as the power module area, control unit area, and cooling system area. Abnormal data is analyzed to determine the area where the anomaly occurred; for example, a temperature anomaly occurs in the cooling system area, while a voltage anomaly occurs in the power module area. The specific circuit within the abnormal area is identified using the equipment's circuit diagram. The circuit diagram details the electrical connections of various components within the equipment. By analyzing abnormal data and the circuit diagram, the specific abnormal circuit is determined; for example, an anomaly in the cooling system area is related to the cooling fan control circuit, and an anomaly in the power module area is related to the supercapacitor's charging / discharging circuit.

[0048] Furthermore, key parameters of the network-type SVG device during the discharge process are collected. Based on these key parameters and the distribution location of abnormal circuits, multiple sub-maintenance areas are determined. The maintenance area of ​​the network-type SVG device is then determined based on these sub-maintenance areas and the circuit diagram of the network-type SVG device. This comprehensive approach, considering both sub-maintenance areas and the circuit diagram, ensures the accuracy of the maintenance area. Simultaneously, a safety interlock mechanism and maintenance events for the network-type SVG device are introduced, taking into account abnormal circuits and key parameters during the discharge process. This further improves the accuracy of the maintenance area and enhances the repair effectiveness of the network-type SVG device under safe conditions.

[0049] During the discharge process, key operating parameters of the equipment are collected in real time. These parameters include, but are not limited to: discharge current (monitoring the discharge current); discharge voltage (monitoring the discharge voltage); discharge power (calculating the discharge power); equipment temperature (monitoring the temperature of key internal components); and grid parameters (monitoring grid voltage, current, and power factor). Based on the collected key parameters and the distribution of abnormal circuits, multiple sub-maintenance areas are determined. The collected key parameters are analyzed to identify abnormal data. For example, a continuous rise in equipment temperature indicates a problem with the cooling system. Based on the abnormal data and circuit distribution diagram, the abnormal area is further divided into multiple sub-maintenance areas. For example, the cooling system area can be divided into a cooling fan area and a coolant circulation area. Combining the information from all sub-maintenance areas, the overall maintenance area of ​​the equipment is determined. The maintenance area should cover all components and circuits requiring maintenance. A detailed maintenance plan is developed based on the maintenance area, including components to be replaced and circuits to be inspected. Optionally, a comprehensive analysis may determine that the overall maintenance area of ​​the equipment includes the cooling fan area and the coolant circulation area of ​​the cooling system area. The maintenance plan may include replacing the cooling fan and inspecting the coolant circulation pipes.

[0050] In another embodiment of this application, a cascaded network-type SVG device is introduced. As a type of network-type SVG device, the entire electrical topology of the cascaded network-type SVG device includes a fast circuit breaker, cascaded power units, supercapacitors, H-bridge inverters, and reduced resistance. The system device includes a central controller that integrates a voltage detection module, mode switching logic, and communication interface to achieve multi-unit collaborative control. The central processing unit is based on an FPGA+ARM dual-core architecture. The FPGA is responsible for real-time discharge control (response period ≤ 10μs), and the ARM is responsible for communication and status monitoring.

[0051] A grid-type SVG power module includes an H-bridge inverter, an interface circuit with a supercapacitor, a bidirectional Buck-Boost DC / DC module (input range 60-850V, output regulated 800V), a holding mechanical switch, a reduction resistor (10Ω / 200W), and a supercapacitor cluster (composed of n capacitor modules, with a final equivalent capacitance within 10F, and a total rated operating voltage of 850V). The DC / DC current uses a four-phase interleaved parallel connection to control harmonics during operation. To reduce losses, silicon carbide MOSFETs are used as switching transistors. A voltage detection module with a high-precision differential voltage sensor (accuracy ±0.5%) is configured in the power unit to monitor the supercapacitor voltage in real time. The power unit is equipped with a resistor-operated fast switch using a magnetic latching relay (operating time ≤5ms) to switch between the supercapacitor and reduction resistor circuits.

[0052] A discharge method for supercapacitor-based grid SVG is introduced, which covers the first stage, the second stage, and the final stage. In the first phase, when the grid-connected SVG device receives a power outage command, the KM1 and 2 switches maintaining the main circuit connection to the grid remain closed. The device switches from its previous operating modes to discharge mode, detecting a supercapacitor voltage ≥450V. Simultaneously, the grid voltage remains normal (fluctuating ±10%). The DC / DC circuit operates in bypass mode, and then the fast phase grid feed mode is initiated, discharging at constant power. A PI control algorithm based on grid voltage feedforward is used. The inverter output current reference value is calculated using the following formula:

[0053] in, The preset discharge power is (e.g., 20kW / unit). Iref This is the reference current, i.e., the reference value of the inverter output current. Vgrid ω is the grid voltage, i.e. the voltage of the grid to which the SVG device is connected; ω is the grid angular frequency; and Φ is the phase angle of the grid voltage, used to determine the phase of the synchronous inverter output current relative to the grid voltage.

[0054] Weak grid support: When the grid impedance ratio (SCR) < 3, switch to virtual synchronous generator (VSG) control mode to dynamically adjust the discharge power.

[0055] in, Where K is the virtual impedance, and K is the adaptive coefficient. This refers to the discharge power, specifically the active power released by the SVG device to the power grid. Vgrid This refers to the grid voltage, specifically the voltage of the power grid to which the SVG device is connected. VscThis refers to the supercapacitor voltage, specifically the voltage of the supercapacitor in the SVG device. When detecting grid frequency deviation, the discharge current phase angle is dynamically corrected to prevent frequency loss of synchronization.

[0056] For the second stage, when the supercapacitor voltage is detected to be <450V or ≥60V, and the power grid is normal, the DC / DC converter quickly starts in boost mode, stabilizes the DC side voltage of the H-bridge inverter at 450V, and keeps the whole machine continuously feeding power to the grid and discharging at constant power.

[0057] In some instances, the DC / DC boost is dynamically adjusted, with the boost duty cycle D adjusted according to the voltage of the supercapacitor. Real-time calculation, ; Supercapacitor voltage refers to the voltage across a supercapacitor. Bus voltage typically refers to the voltage of the DC bus in the system. To prevent frequent switching, voltage hysteresis control is required, with an appropriate loop width voltage set. The DC / DC boost circuit uses a four-phase interleaved parallel Buck-Boost circuit to reduce inductor current ripple (ripple rate <10%). Within the input range of 60-450V, the conversion efficiency is ≥93%. Low-loss SiC MOSFET devices are used. The DC / DC circuit features fault-tolerant control and single-phase fault isolation: when the current in a phase exceeds the limit (>30A), the FPGA triggers hardware protection to shut down the corresponding MOSFET, and the power of the remaining three phases is automatically balanced. Voltage drop compensation: when the supercapacitor voltage suddenly drops, feedforward compensation duty cycle is used. .

[0058] at this time, The compensated duty cycle is used to adjust the on-time of switching devices in the control system to achieve voltage sag compensation. This refers to the feedforward compensation coefficient, used to adjust the strength of the feedforward compensation. In the text, This indicates that the feedforward compensation coefficient is 0.02. The change in supercapacitor voltage is the variable in the signal. In a control system, feedforward compensation is a control strategy that adjusts the control signal in advance by predicting the system response. Here, duty cycle (D) refers to the ratio of the on-time of a switching device in one cycle to the total on-time.

[0059] In the final stage, if the supercapacitor voltage is <60V and does not recover for a certain period of time, the entire equipment will shut down. Then, the KM1 and 2 circuit breakers of the main circuit will be disconnected, and a signal will be quickly sent to the parallel resistor switch of the supercapacitor to control its activation, switching to the resistance reduction stage until the supercapacitor discharge is completed. In addition, during the above discharge stage, corresponding safety protection mechanisms will be implemented. The series fuse of the reduction circuit will be forcibly cut off when the current reaches the set value. The temperature sensor (PT100) installed in the reduction resistor will trigger an alarm and derating discharge when the temperature is >120℃. If any power unit fails, the central controller will bypass it, and the remaining units will automatically adjust the discharge power distribution. When the above discharge drops to below 36V, which is below the safe voltage for human contact, the system will automatically trigger the mechanical latch of the cabinet door, and the maintenance door can be unlocked. The system can also notify maintenance personnel that the discharge is complete through LED indicator lights and the remote monitoring system.

[0060] Please see Figure 7 , Figure 7 This is a schematic diagram of the structural composition of the discharge system of the supercapacitor-based grid SVG in an embodiment of the present invention; the discharge system of the supercapacitor-based grid SVG includes: The first-stage module 21 is used to determine the maintenance status of the grid-type SVG device based on multiple working data of the grid-type SVG device, and output a discharge command. Based on the discharge command, the first-stage controllable constant power discharge mode of the grid-type SVG device is triggered to feed energy back to the grid. The second-stage module 22 is used to trigger the operation of the boost circuit based on the voltage drop of the supercapacitor and maintain the constant bus voltage, so that the grid-type SVG equipment enters the constant power discharge mode of the second stage. The final discharge stage module 23 is used to feed energy back to the grid at a constant power when the grid-type SVG device is in the constant power discharge mode of the second stage, until the voltage of the supercapacitor drops below the safe voltage. At this time, the grid-type SVG device is in the reduced power discharge mode of the final discharge stage. Safety interlock module 24 is used to activate the safety interlock mechanism of the grid-type SVG device and collect maintenance events of the grid-type SVG device when the grid-type SVG device is in the reduced power discharge mode of the final discharge stage. The maintenance module 25 is used to determine the corresponding abnormal circuit based on the abnormal detection of the network-type SVG device in the maintenance event of the network-type SVG device, and to determine the maintenance area of ​​the network-type SVG device based on the abnormal circuit and the key parameters of the network-type SVG device during the discharge process.

[0061] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A discharge method for a supercapacitor-based SVG network, characterized in that, include: The maintenance status of the grid-type SVG device is determined based on multiple working data of the grid-type SVG device, and a discharge command is output. Based on the discharge command, the first stage of the controllable constant power discharge mode of the grid-type SVG device is triggered to feed energy back to the grid. The voltage drop of the supercapacitor triggers the operation of the boost circuit and maintains a constant bus voltage, allowing the grid-type SVG equipment to enter the second stage of constant power discharge mode. When the grid-type SVG device is in the second stage of constant power discharge mode, the grid-type SVG device feeds energy back to the grid at a constant power until the voltage of the supercapacitor drops below the safe voltage. At this time, the grid-type SVG device is in the final discharge stage of reduced power discharge mode. When the grid-type SVG device is in the reduced power discharge mode during the final discharge stage, the safety interlock mechanism of the grid-type SVG device is activated, and the maintenance events of the grid-type SVG device are collected. In maintenance events of network-type SVG devices, the corresponding abnormal circuit is determined based on the abnormal detection of the network-type SVG device, and the maintenance area of ​​the network-type SVG device is determined based on the abnormal circuit and the key parameters of the network-type SVG device during the discharge process.

2. The discharge method for SVG based on a supercapacitor network according to claim 1, characterized in that, The process involves determining the maintenance status of the grid-type SVG device based on multiple operating data points, outputting a discharge command, and triggering the first stage of the controllable constant power discharge mode of the grid-type SVG device according to the discharge command to feed energy back to the grid, including: Real-time monitoring of network-type SVG devices; collection of multiple working data from network-type SVG devices; determination of the status of network-type SVG devices based on multiple working data and the working duration of the network-type SVG device model. When the grid-type SVG device is in maintenance mode, it outputs a discharge command. The discharge content of the grid-type SVG device is determined by parsing the discharge command. The mode switching of the grid-type SVG device is triggered according to the discharge content. At this time, the grid-type SVG device is in a controllable constant power discharge mode and performs the first stage of discharge. The discharge efficiency corresponding to the first stage is collected, and the grid-type SVG device feeds back energy to the grid along the discharge efficiency.

3. The discharge method for SVG based on a supercapacitor network according to claim 1, characterized in that, The voltage drop based on the supercapacitor triggers the operation of the boost circuit, maintaining a constant bus voltage. The grid-type SVG device then enters the second stage of constant power discharge mode, including: The operation of the supercapacitor is monitored in real time, and the current voltage of the supercapacitor is collected. At the same time, a first set voltage is collected, and the voltage drop of the supercapacitor is determined by comparing the first set voltage with the current voltage of the supercapacitor. Collect the circuit diagram of the network-type SVG device, determine the corresponding boost circuit based on the voltage drop of the supercapacitor, the supercapacitor model, and the circuit diagram of the network-type SVG device, and trigger the operation of the boost circuit. During the operation of the boost circuit, the boost circuit maintains the DC bus voltage of the power unit H-bridge at a set constant value to maintain the constant bus voltage. At this time, the grid-type SVG equipment enters the second stage of constant power discharge mode.

4. The discharge method for SVG based on a supercapacitor network according to claim 1, characterized in that, When the grid-connected SVG device is in the second stage of constant power discharge mode, it feeds energy back to the grid at a constant power until the voltage of the supercapacitor drops below the safe voltage. At this point, the grid-connected SVG device is in the final discharge stage of reduced power discharge mode, including: The second-stage constant power discharge mode of the grid-type SVG device is monitored in real time, and the corresponding constant power is collected. The grid-type SVG device feeds energy back to the grid under constant power discharge operation, and the voltage of the supercapacitor is collected at different times.

5. The discharge method for SVG based on a supercapacitor network according to claim 4, characterized in that, When the grid-connected SVG device is in the second stage of constant power discharge mode, the grid-connected SVG device feeds energy back to the grid at a constant power until the voltage of the supercapacitor drops below the safe voltage. At this time, the grid-connected SVG device is in the final discharge stage of reduced power discharge mode, which also includes: Collect the safe voltage, compare the voltage of the supercapacitor at different times with the safe voltage, and mark the time points when the voltage of the supercapacitor drops below the safe voltage; Based on the control of the discharge operation of the grid-type SVG device triggered at this time node, the grid-type SVG device is adjusted from the constant power discharge mode in the second stage to the reduced power discharge mode in the final discharge stage.

6. The discharge method for SVG based on a supercapacitor network according to claim 1, characterized in that, When the grid-type SVG device is in the reduced power discharge mode during the final discharge phase, the safety interlock mechanism of the grid-type SVG device is activated, and maintenance events of the grid-type SVG device are collected, including: The real-time grid-type SVG device uses a reduced power discharge mode during the final discharge stage to monitor the real-time voltage of the supercapacitor and maintain the real-time voltage of the supercapacitor below the safe voltage. Security management is implemented for network-type SVG devices. The security management path of the network-type SVG devices is determined based on the security management signals of the network-type SVG devices. Based on the security management path and the circuit distribution diagram of the network-type SVG devices, a security interlock mechanism is determined to activate the security interlock mechanism of the network-type SVG devices. The interlock mechanism is controlled by both hardware and software to ensure that the network-type SVG devices cannot be started by accidental operation before maintenance.

7. The discharge method for SVG based on a supercapacitor network according to claim 6, characterized in that, The method of activating the safety interlock mechanism of the grid-type SVG device and collecting maintenance events of the grid-type SVG device during the reduced power discharge mode in the final discharge stage also includes: Under the control of the safety interlock mechanism, the network-type SVG device is activated and multiple maintenance data of the network-type SVG device are collected. Based on the multiple maintenance data, the status of the network-type SVG device, and the safety interlock mechanism, the maintenance event of the network-type SVG device is determined.

8. The discharge method for SVG based on a supercapacitor network according to claim 1, characterized in that, In the maintenance event of the network-type SVG device, the corresponding abnormal circuit is determined based on the abnormal detection of the network-type SVG device, and the maintenance area of ​​the network-type SVG device is determined based on the abnormal circuit and the key parameters of the network-type SVG device during the discharge process, including: Real-time monitoring of maintenance events of network-type SVG devices, and anomaly detection of network-type SVG devices. Based on the anomaly detection of network-type SVG devices, the corresponding abnormal areas are determined, and based on the abnormal areas and the circuit distribution diagram of network-type SVG devices, the corresponding abnormal circuits are determined.

9. The discharge method for SVG based on a supercapacitor network according to claim 8, characterized in that, In the maintenance event of the network-type SVG device, the method of determining the corresponding abnormal circuit based on the abnormal detection of the network-type SVG device, and determining the maintenance area of ​​the network-type SVG device based on the abnormal circuit and key parameters of the network-type SVG device during the discharge process, further includes: Key parameters of the grid-type SVG device during the discharge process are collected. Based on the key parameters of the grid-type SVG device during the discharge process and the distribution location of abnormal circuits, multiple sub-maintenance areas are determined. Based on the multiple sub-maintenance areas and the circuit distribution diagram of the grid-type SVG device, the maintenance area of ​​the grid-type SVG device is determined.

10. A discharge system for a supercapacitor-based grid SVG, characterized in that, The discharge system of the supercapacitor-based grid SVG is applied to the discharge method of the supercapacitor-based grid SVG as described in any one of claims 1-9, wherein the discharge system of the supercapacitor-based grid SVG comprises: The first-stage module is used to determine the maintenance status of the grid-type SVG device based on multiple working data of the grid-type SVG device, and output a discharge command. Based on the discharge command, the first-stage controllable constant power discharge mode of the grid-type SVG device is triggered to feed energy back to the grid. The second-stage module is used to trigger the operation of the boost circuit based on the voltage drop of the supercapacitor and maintain the constant bus voltage, so that the grid-type SVG equipment enters the second-stage constant power discharge mode. The final discharge stage module is used when the grid-type SVG device is in the constant power discharge mode of the second stage. The grid-type SVG device feeds energy back to the grid at a constant power until the voltage of the supercapacitor drops below the safe voltage. At this time, the grid-type SVG device is in the reduced power discharge mode of the final discharge stage. The safety interlock module is used to activate the safety interlock mechanism of the grid-type SVG device when the grid-type SVG device is in the reduced power discharge mode during the final discharge stage, and to collect maintenance events of the grid-type SVG device. The maintenance module is used to determine the corresponding abnormal circuit based on the abnormal detection of the network-type SVG device during maintenance events, and to determine the maintenance area of ​​the network-type SVG device based on the abnormal circuit and the key parameters of the network-type SVG device during the discharge process.

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