Rapid arc light fault isolation protection device for high-voltage switch cabinet of thermal power plant

Abstract

The invention discloses a rapid arc light fault isolation protection device for a high-voltage switch cabinet of a thermal power plant, relates to the technical field of high-voltage switch cabinets, and aims to solve the problems of full development of electric arcs and huge energy caused by more links and overlong accumulated time from sensor detection, signal transmission, logic judgment to circuit breaker opening. According to the technical scheme, the system is characterized in that the system comprises a high-voltage switch unit cabinet, an arc light detector is fixedly installed in the center of the top of the high-voltage switch unit cabinet, a plurality of ultrasonic sensors are evenly distributed on the periphery of the arc light detector, and the arc light detector and the ultrasonic sensors are electrically connected with a central controller module through data lines; an arc light detector and an ultrasonic sensor are arranged. The effects that the maloperation probability is extremely low, waiting for the current criterion is avoided, the three-dimensional coordinates of the fault point can be output, the fault point can be accurately positioned to a specific compartment or even the vicinity of specific equipment, and the protection mode of passive waiting for tripping is fundamentally changed are achieved.

Description

Technical Field

[0001] This invention relates to the field of high-voltage switchgear technology, and in particular to a rapid isolation and protection device for arc faults in high-voltage switchgear of thermal power plants. Background Technology

[0002] High-voltage switchgear is a critical piece of equipment in the power system of thermal power plants. An arc flash short circuit fault within it can generate enormous heat and pressure in a very short time, leading to severe equipment damage and even personal injury. Currently, common arc flash protection schemes mainly rely on arc flash sensors installed inside the switchgear in conjunction with overcurrent signals for judgment. Arc flash sensors detect visible light or light of specific wavelengths. A typical architecture involves fixing multiple point-type arc flash sensors in key compartments such as the switchgear busbar compartment, circuit breaker compartment, and cable compartment. Simultaneously, current signals are obtained from current transformers. When the protection device detects both the arc flash signal and the overcurrent signal, it issues a trip command after a short delay (to prevent false tripping), cutting off the power to the faulty circuit. In addition, some schemes attempt to combine multiple sensors, such as pressure and temperature sensors, for comprehensive judgment to improve the accuracy of the action.

[0003] Although existing technologies have achieved arc flash protection to a certain extent, they still have the following specific defects affecting speed and reliability: Most solutions require both "arc flash signal + overcurrent signal" criteria to be met simultaneously to trigger tripping. However, in the early stages of minor short circuits or arc flash faults at specific locations, the fault current may not reach the overcurrent setting, causing the protection device to enter a waiting or locked state, missing the optimal isolation opportunity, and allowing arc energy to continue to accumulate. At the same time, existing solutions only attempt to cut off the power supply, without applying direct physical intervention during the "golden window" of arc generation and energy accumulation. From sensor detection, signal transmission, logic judgment to circuit breaker tripping, there are many links and the cumulative time is too long, resulting in the arc having fully developed and accumulating huge energy. In addition, the isolation action depends entirely on the reliability of the upstream circuit breaker. If the circuit breaker itself fails to operate or the operating mechanism malfunctions, the protection will be completely ineffective. Therefore, this invention provides a fast isolation protection device for arc flash faults in high-voltage switchgear of thermal power plants. Summary of the Invention

[0004] The purpose of this invention is to provide a fast isolation and protection device for arc faults in high-voltage switchgear of thermal power plants that is simple in structure, easy to install, and cost-controllable.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A rapid isolation and protection device for arc flash faults in high-voltage switchgear of a thermal power plant includes a high-voltage switch unit cabinet. The front of the high-voltage switch unit cabinet is hinged to a cabinet door, and an electrical component mounting bracket is fixedly connected to the back of the cabinet's inner cavity. Electrical components are mounted on the mounting bracket, and these components are connected to a busbar via isolating contacts.

[0007] An arc detector is fixedly installed at the top center of the high-voltage switch unit cabinet, and an ultrasonic sensor is fixedly installed inside the high-voltage switch unit cabinet. Multiple ultrasonic sensors are evenly distributed around the arc detector.

[0008] The arc detector and the ultrasonic sensor are electrically connected to a central controller module via a data line. The central controller module has preset protection logic and a synchronization timing unit.

[0009] Multiple ultrasonic sensors are fixedly installed in a non-collinear geometric distribution within the internal space of the switch cabinet;

[0010] The high-voltage switch unit cabinet is equipped with a fast isolation protection module, which includes an active arc extinguishing and suppression unit and a physical isolation unit. The active arc extinguishing and suppression unit is used to spray arc extinguishing medium toward the calculated fault point coordinates, and the physical isolation unit is used to drive the busbar connection of electrical components to separate and isolate the power supply to form a physical isolation barrier.

[0011] Through the above technical solution, the central controller module has a preset protection logic: when the trigger signal of the arc detector is received, the timestamps of the pressure wave signals received by multiple ultrasonic sensors are immediately collected and analyzed. By calculating the time difference of the pressure wave reaching different ultrasonic sensors, the three-dimensional spatial coordinates of the fault point are calculated and compared with the preset coordinates of the "fault danger area" in the switch cabinet in the central controller module. If the calculated fault point coordinates are located in the "fault danger area", the trip command and isolation protection command are immediately sent to the fast isolation protection module.

[0012] Furthermore, the synchronization timing unit is used to provide a uniform high-precision timestamp for all ultrasonic sensors, at least one of which is installed on the inside of the top panel of the switch cabinet, and at least two of which are respectively installed on the inside of adjacent vertical side panels.

[0013] Through the above technical solution, the installation positions of the ultrasonic sensors are optimized: at least one is installed on the inside of the top panel of the switch cabinet, and at least two are installed on the inside of adjacent vertical side panels, forming a tetrahedral or more complex spatial geometric network that can at least cover the main equipment space of the switch cabinet.

[0014] Furthermore, the synchronization timing unit adopts a GPS / BeiDou dual-mode timing module to provide a unified microsecond-level clock synchronization signal for the central controller module and the timing circuit in each ultrasonic sensor, ensuring that the timestamps generated by each ultrasonic sensor are based on the same time reference.

[0015] Furthermore, the ultrasonic sensor is a broadband acoustic emission sensor, and each ultrasonic sensor has a built-in signal preprocessing circuit for amplifying and bandpass filtering the original vibration signal. The ultrasonic sensor is equipped with a leading edge detection circuit for generating a trigger pulse with a precise timestamp when the pressure wave signal first exceeds the threshold.

[0016] Furthermore, the protection logic within the central controller module specifically includes the following steps:

[0017] S1: Continuously monitor the arc detector signal. Once the first trigger signal is received, immediately start high-speed data acquisition and record the original waveform data and timestamp sequence of each ultrasonic sensor from this moment on.

[0018] S2: Perform waveform feature analysis on the first arriving pressure wave signal, i.e. the signal that arrives first at any ultrasonic sensor, to verify whether it has the typical characteristics of an electric arc pressure wave.

[0019] S3: Accurately extract the times T1, T2, T3... when the pressure wavefront arrives at at least three non-collinear ultrasonic sensors from the recorded time-series data;

[0020] S4: Based on the known spatial coordinates (Si(x,y,z)) of each ultrasonic sensor and the propagation speed v of the pressure wave in the medium inside the switch cabinet, the fault point coordinates P(x,y,z) satisfying the equation set “distance difference = propagation speed × time difference” are solved using the time difference positioning algorithm.

[0021] S5: Compare the calculated fault point coordinates P with the coordinates of the "fault danger area" defined in the three-dimensional digital model of the switchgear pre-stored in the central controller module;

[0022] S6: If P is located within the "fault danger zone", it is determined to be a confirmed arcing fault inside the cabinet. Without any delay, a trip command and isolation protection command will be issued immediately. If P is located outside the zone, it is determined to be external interference or non-fault discharge. An alarm will be activated but the circuit will not trip.

[0023] By utilizing the instantaneous nature of ultraviolet light and the rapid calculation of pressure wave time difference positioning, the total action time can be controlled within ms, or even down to -ms, greatly suppressing arc energy. Pressure wave time difference positioning provides key information on "where" the fault occurred inside the cabinet, achieving physical location-based selectivity. It eliminates the need to introduce and process sensitive analog current signals for protection functions, reducing the difficulty of electromagnetic compatibility design and improving the overall stability of the system.

[0024] Furthermore, the protection logic within the central controller module also includes self-verification and anti-interference steps: During normal operation, the central controller module periodically issues a self-verification command, generating a simulated pressure wave through a miniature calibration sound source installed in a non-hazardous area of ​​the high-voltage switch unit cabinet. Each ultrasonic sensor receives the calibration signal, and the central controller module calculates the arrival time difference of the calibration signal, inverts the actual propagation speed v' of the pressure wave in real time, and dynamically corrects the velocity parameter v in the positioning algorithm to compensate for the change in sound speed caused by changes in temperature and gas density of the high-voltage switch unit cabinet.

[0025] Furthermore, the active arc extinguishing suppression unit includes an arc extinguishing jet and an arc extinguishing medium chamber. The arc extinguishing jet is fixedly installed on the front end of the inner wall of the high-voltage switch unit cabinet, and the arc extinguishing medium chamber is fixedly installed on the lower end of the high-voltage switch unit cabinet.

[0026] Multiple arc-extinguishing nozzles are fixedly connected to the inner side of the arc-extinguishing jet row, and the nozzle outlet of the arc-extinguishing nozzle is inclined toward the junction of the moving and stationary contacts and the wiring position of the isolating contacts of the circuit breaker on the electrical component mounting bracket.

[0027] The arc-extinguishing medium chamber has an internal hollow structure. An ultra-high-speed solenoid valve is fixedly connected to the bottom of the inner cavity of the arc-extinguishing medium chamber, and an inert gas storage tank is inserted into the front side of the arc-extinguishing medium chamber. A fixing and clamping plug is threadedly connected to the outer side of the inner wall of the arc-extinguishing medium chamber, and the fixing and clamping plug abuts against the front side of the inert gas storage tank. The inlet of the inert gas storage tank is inserted and fixedly connected to the air inlet of the ultra-high-speed solenoid valve. The air outlet of the ultra-high-speed solenoid valve is connected to multiple arc-extinguishing nozzles and physical isolation units through an air distribution valve.

[0028] The above technical solution can output the three-dimensional coordinates of the fault point, accurately locate it to a specific compartment or even near a specific piece of equipment, and provide high-value information for rapid fault diagnosis, repair and power restoration. In addition, it actively sprays arc-extinguishing medium and provides rapid physical isolation, directly physically intervening in and spatially isolating the arc before the electrical circuit breaker operates, fundamentally changing the passive waiting protection mode.

[0029] Furthermore, the gas distribution valve is connected to multiple arc-extinguishing nozzles through an internal pipeline, and the multiple arc-extinguishing nozzles are each connected to a branch of the internal pipeline through an independent shut-off valve.

[0030] Through the above technical solution, in actual operation, the independent shut-off valve can be manually opened and closed according to whether electrical components are installed in the arc-extinguishing nozzle, so as to ensure that only the arc-extinguishing nozzle facing the position where electrical components are installed and arc failure may occur will spray the arc-extinguishing medium, thus avoiding unnecessary waste of the medium.

[0031] Furthermore, the physical isolation unit includes a power base and an isolation element terminal block. The power base is installed on the upper end of the arc-extinguishing medium chamber, and the isolation element terminal block is installed on the upper end of the power base.

[0032] The isolation element terminal block is provided with a terminal block, and the electrical components on the electrical component mounting bracket are all connected to the busbar and output cable through the terminal block. The upper ends of both sides of the power base are embedded with expansion lifting rubber bladders, and the top of the expansion lifting rubber bladders abuts against the bottom of both sides of the isolation element terminal block.

[0033] The power base has a square groove in the center, and a fuse connection bar is set in the center of the square groove. A fuse protector is set in the fuse connection bar for multiple connected lines. Multiple power plugs are fixedly connected to the bottom of the isolation element terminal block, and the multiple power plugs are electrically connected to multiple terminals on the terminal block. The multiple power plugs are inserted into the isolation contacts of the fuse protectors in the fuse connection bar in pairs. The expansion lifting rubber bladders on both sides are connected to the square groove in the center of the power base through a throttle valve. Multiple through injection ports are evenly opened on the bottom of the corresponding terminals on the isolation element terminal block.

[0034] Furthermore, the arc detector is an ultraviolet light sensor structure with a solar-blind filter cover at the bottom. A reflector is fixedly connected to the back of the cabinet door corresponding to the position of the electrical component mounting bracket. Multiple focusing mirrors are evenly distributed inside the reflector. The focusing mirrors are an array of reflectors mounted at an angle, used to reflect the light from the arc point on the electrical component mounting bracket toward the photosensitive position of the ultraviolet light sensor of the arc detector.

[0035] Through the above technical solution, the independent shut-off valve can be manually opened and closed according to whether electrical components are installed in the arc-extinguishing nozzle, so as to ensure that only the arc-extinguishing nozzle facing the position where electrical components are installed and arc failure may occur will spray the arc-extinguishing medium, thus avoiding unnecessary waste of the medium.

[0036] In summary, the beneficial technical effects of the present invention are as follows:

[0037] 1. By using the arc detector and ultrasonic sensor, the system employs two physically independent characteristic quantities, "ultraviolet light (optical)" and "pressure wave (acoustic)," which are almost entirely generated by internal arc faults, to make a joint judgment. This results in an extremely low probability of false triggering and eliminates the need to wait for current criteria.

[0038] 2. By utilizing the instantaneous nature of ultraviolet light and the rapid calculation of pressure wave time difference positioning, the total action time can be controlled within 5ms, or even 2-3ms, which greatly suppresses arc energy. Pressure wave time difference positioning provides key information on "where" the fault occurred in the cabinet, realizing physical location-based selectivity. There is no need to introduce and process sensitive analog current signals for protection functions, which reduces the difficulty of electromagnetic compatibility design and improves the overall stability of the system.

[0039] 3. It can output the three-dimensional coordinates of the fault point, accurately locate the specific compartment or even the vicinity of the specific equipment, and provide high-value information for rapid fault diagnosis, repair and power restoration. In addition, it actively sprays arc-extinguishing medium and provides rapid physical isolation, directly physically intervening and spatially isolating the arc before the electrical circuit breaker operates, fundamentally changing the passive waiting trip protection mode. Attached Figure Description

[0040] Figure 1 This is a three-dimensional structural schematic diagram of the present invention;

[0041] Figure 2 This is a schematic diagram of the overhead section structure of the present invention;

[0042] Figure 3 This is a top-sectional view of the present invention;

[0043] Figure 4 This is a side cross-sectional structural diagram of the location of the arc-extinguishing medium chamber in this invention;

[0044] Figure 5 This is a side sectional view of the switch cabinet center position of the present invention.

[0045] In the diagram, 1. High-voltage switch unit cabinet; 2. Cabinet door; 3. Electrical component mounting bracket; 4. Reflector; 5. Concentrating reflector; 6. Arc detector; 7. Ultrasonic sensor; 8. Arc extinguishing jet; 9. Arc extinguishing nozzle; 10. Arc extinguishing medium chamber; 11. Power connection base; 12. Isolation element terminal block; 13. Terminal block; 14. Inert gas storage tank; 15. Ultra-high-speed solenoid valve; 16. Gas distribution valve; 17. Fixed clamping plug; 18. Independent shut-off valve; 19. Power connector; 20. Expansion lifting rubber bladder; 21. Fuse connection bar. Detailed Implementation

[0046] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0047] Reference Figure 1 A rapid isolation and protection device for arc faults in high-voltage switchgear of a thermal power plant includes a high-voltage switch unit cabinet 1. A cabinet door 2 is installed on the front side of the high-voltage switch unit cabinet 1, and an electrical component mounting bracket 3 is fixedly connected to the back side of the inner cavity of the high-voltage switch unit cabinet 1. Electrical components are mounted on the mounting bracket 3, and the electrical components are connected to a busbar through isolation contacts. An arc detector 6 is fixedly installed at the top center of the high-voltage switch unit cabinet 1, and multiple ultrasonic sensors 7 are evenly distributed around the arc detector 6. The arc detector 6 and the ultrasonic sensors 7 are electrically connected to a central controller module via a data cable. The central controller module has preset protection logic: upon receiving a trigger signal from the arc detector 6, it immediately... The system aggregates and analyzes the timestamps of pressure wave signals received by multiple ultrasonic sensors 7. By calculating the time difference of the pressure wave reaching different ultrasonic sensors 7, the three-dimensional spatial coordinates of the fault point are calculated and compared with the coordinates of the "fault danger zone" in the switch cabinet preset in the central controller module. If the calculated fault point coordinates are located within the "fault danger zone", a trip command and an isolation protection command are immediately sent to the fast isolation protection module. The fast isolation protection module includes an active arc extinguishing and suppression unit and a physical isolation unit. The active arc extinguishing and suppression unit is used to spray arc extinguishing medium at the calculated fault point coordinates, and the physical isolation unit is used to drive the busbar connection of electrical components to separate and isolate the power supply to form a physical isolation barrier.

[0048] Multiple high-voltage switchgear units 1 are stacked and connected to the power supply. In actual operation, when an arc fault occurs in one of the high-voltage switchgear units 1, the arc detector 6 on the top of the unit will quickly detect the arc and send a trigger signal. After receiving this signal, the central controller module will immediately start working according to the preset logic. It will immediately collect the timestamps of the pressure wave signals received by multiple surrounding ultrasonic sensors 7. Since the pressure wave generated at the fault point takes different amounts of time to propagate to the ultrasonic sensors 7 at different locations, the central controller module can calculate the three-dimensional spatial coordinates of the fault point by accurately calculating these time differences. If the calculated fault point coordinates are within the "fault danger zone", the central controller module will quickly send trip and isolation protection commands to the fast isolation protection module. The active arc extinguishing and suppression unit will respond quickly and accurately spray the arc extinguishing medium according to the calculated fault point coordinates. This arc extinguishing medium has high-efficiency arc extinguishing performance and can quickly suppress the arc and reduce the severity of the fault. At the same time, the physical isolation unit will also act immediately to drive the busbar connection of the electrical components to separate, isolate the power supply, and form a physical isolation barrier to prevent the fault from spreading further to other high-voltage switchgear units.

[0049] This invention utilizes an arc detector 6 and an ultrasonic sensor 7 to jointly determine the fault using two physically independent characteristic quantities: "ultraviolet light" and "pressure wave," which are almost exclusively generated by internal arc faults. This results in an extremely low probability of false tripping and eliminates the need to wait for current criteria. By leveraging the instantaneous nature of ultraviolet light and the rapid calculation of pressure wave time difference positioning, the entire action time can be controlled within 5ms, or even as low as 2-3ms, greatly suppressing arc energy. Pressure wave time difference positioning provides crucial information on "where" the fault occurs within the cabinet, enabling physical location-based selectivity. It eliminates the need to introduce and process sensitive analog current signals for protection functions, reducing the difficulty of electromagnetic compatibility design and improving the overall stability of the system. Furthermore, it can output the three-dimensional coordinates of the fault point, accurately locating it to a specific compartment or even near a specific piece of equipment. This provides valuable information for rapid fault diagnosis, repair, and power restoration. Moreover, the active spraying of arc-extinguishing media and rapid physical isolation directly intervene in and spatially isolate the arc before the circuit breaker trips, fundamentally changing the passive waiting-for-trip protection mode.

[0050] Reference Figure 2Multiple ultrasonic sensors 7 are fixedly installed in a non-collinear geometric distribution within the switchgear's internal space. A synchronization time base unit is installed on the central controller module, providing a unified high-precision timestamp for all ultrasonic sensors 7. The installation positions of the ultrasonic sensors 7 are optimized: at least one is installed inside the top panel of the switchgear, and at least two are installed inside adjacent vertical side panels, forming a tetrahedral or more complex spatial geometric network that at least covers the main equipment space of the switchgear. This ensures that the time difference of pressure waves reaching at least three sensors at any location within the cabinet where arcing may occur is resolvable, improving the accuracy and reliability of fault location. Simultaneously, this optimized installation layout allows the sensors to capture pressure wave signals more comprehensively, avoiding detection blind spots. The synchronization time base unit uses a GPS / BeiDou dual-mode timing module to provide a unified microsecond-level clock synchronization signal for the central controller module and the timing circuit within each ultrasonic sensor 7, ensuring that the timestamps generated by each ultrasonic sensor 7 are based on the same time. The benchmark ensures the consistency and accuracy of the timestamps generated by each ultrasonic sensor. This allows the central controller module to perform calculations based on precise time data when analyzing the time difference of pressure waves arriving at different sensors, thereby more accurately determining the three-dimensional spatial coordinates of the fault point. The ultrasonic sensor 7 is a broadband acoustic emission sensor with an effective frequency band covering 20kHz~200kHz. Each ultrasonic sensor 7 has a built-in signal preprocessing circuit that amplifies and bandpass filters the original vibration signal and has a leading-edge detection circuit that generates a trigger pulse with a precise timestamp when the pressure wave signal first exceeds the threshold. This enables the sensor to respond quickly to changes in the pressure wave signal and capture the moment the fault occurs. At the same time, the precise timestamp provides a key basis for subsequent fault location analysis. The built-in signal preprocessing circuit, through amplification and bandpass filtering, can effectively enhance the useful signal, suppress noise interference, and improve the signal quality and clarity. This helps the central controller module to more accurately identify and analyze the characteristics of the pressure wave signal.

[0051] Reference Figure 3 The wide bandwidth of the ultrasonic sensor 7 enables it to adapt to pressure wave signals generated by arc faults of various types and intensities. Within the effective frequency band of 20kHz to 200kHz, the sensor can sensitively detect pressure waves of various frequency components, thereby greatly improving its adaptability to different fault scenarios.

[0052] Specifically, the protection logic within the central controller module includes the following steps:

[0053] S1: Continuously monitor the signal of the arc detector 6. Once the first trigger signal is received, immediately start high-speed data acquisition and record the original waveform data and timestamp sequence of each ultrasonic sensor 7 from this moment on.

[0054] S2: Perform waveform feature analysis on the first arriving pressure wave signal, i.e. the signal that first arrives at any ultrasonic sensor 7, to verify whether it has the typical characteristics of an electric arc pressure wave, such as a specific rise edge steepness and spectral characteristics.

[0055] S3: From the recorded time series data, accurately extract the times T1, T2, T3... when the pressure wave front arrives at at least three non-collinear ultrasonic sensors 7;

[0056] S4: Based on the known spatial coordinates (Si(x,y,z)) of each ultrasonic sensor 7 and the propagation speed v of the pressure wave in the medium inside the switch cabinet, the fault point coordinates P(x,y,z) satisfying the equation set “distance difference = propagation speed × time difference” are solved using the time difference positioning algorithm.

[0057] S5: Compare the calculated fault point coordinates P with the coordinates of the "fault danger zone" defined in the three-dimensional digital model of the switchgear pre-stored in the central controller module, which is the spatial region containing all live conductors.

[0058] S6: If P is located within the "fault danger zone", it is determined to be a confirmed arcing fault inside the cabinet. Without any delay, a trip command and isolation protection command will be issued immediately. If P is located outside the zone, such as near the cabinet wall or observation window, it is determined to be external interference or non-fault discharge. An alarm will be activated but the circuit breaker will not trip.

[0059] The protection logic within the central controller module significantly improves the accuracy of fault diagnosis through multi-dimensional monitoring and analysis. It continuously monitors the arc detector signal and immediately initiates high-speed data acquisition, capturing crucial information the instant a fault occurs. The recorded raw waveform data and timestamp sequence provide a solid foundation for subsequent accurate analysis. Waveform feature analysis of the first arriving pressure wave signal effectively identifies the arc pressure wave, eliminates other interference signals, avoids misjudgment, and accurately extracts the arrival time of the pressure wave front at different ultrasonic sensors. Combined with the spatial coordinates of each sensor and the pressure wave propagation speed, a time-difference positioning algorithm accurately calculates the fault point coordinates. These coordinates are then compared with pre-stored three-dimensional digital data of the switchgear. By comparing the coordinates of the "fault danger zone" in the model, the accuracy of fault determination is further ensured. This ensures that no real faults are missed and that unnecessary tripping caused by external interference or non-fault discharge is avoided. This accurate fault judgment and handling method can effectively reduce the harm caused by arcing faults in high-voltage switchgear of thermal power plants. When an arcing fault is confirmed inside the cabinet, a tripping command and isolation protection command are immediately issued to quickly cut off the fault source, prevent the fault from expanding further, protect the equipment from greater damage, and ensure the safe and stable operation of the thermal power plant. When an external interference or non-fault discharge is determined, only an alarm is activated without tripping, avoiding unnecessary power outages, reducing the impact on production, and improving the economic benefits of the thermal power plant.

[0060] Meanwhile, the protection logic also has a certain degree of scalability. It can be further optimized and improved based on actual operating conditions and new fault types. For example, more fault feature analysis methods can be introduced, combined with machine learning algorithms, to learn and analyze historical fault data, continuously improving the accuracy and reliability of fault judgment. The protection device can also be linked with other systems in the thermal power plant to achieve information sharing and collaborative work, further enhancing the automation level and disaster prevention and mitigation capabilities of the thermal power plant.

[0061] Reference Figure 4The protection logic within the central controller module also includes self-verification and anti-interference steps: During normal operation, the central controller module periodically issues a self-verification command, generating a simulated pressure wave through a miniature calibration sound source installed in a non-hazardous area of ​​the high-voltage switch unit cabinet 1. Each ultrasonic sensor 7 receives this calibration signal. The central controller module calculates the arrival time difference of the calibration signal, inverts the actual propagation speed v' of the pressure wave in real time, and dynamically corrects the velocity parameter v in the positioning algorithm to compensate for the changes in sound velocity caused by changes in temperature and gas density in the high-voltage switch unit cabinet 1. This achieves real-time self-verification and adaptive adjustment. This self-verification mechanism ensures that the pressure wave is stable under different operating conditions. Despite the challenging environment, the protection device can still accurately calculate the fault location coordinates. This is because factors such as temperature and gas density within the high-voltage switch unit cabinet change with operating time and environmental conditions. These changes affect the propagation speed of the pressure wave, thus impacting the accuracy of fault location. Through periodic self-checking and dynamic correction of speed parameters, the protection device can adapt to these changes in a timely manner, ensuring that the fault location accuracy remains at a high level. The active arc-extinguishing suppression unit includes an arc-extinguishing jet 8 and an arc-extinguishing medium chamber 10. Multiple arc-extinguishing nozzles 9 are fixedly connected to the inner side of the arc-extinguishing jet 8, and the nozzle outlets of the arc-extinguishing nozzles 9 face the circuit breaker on the electrical component mounting bracket 3. The moving and stationary contact joints and the wiring positions of the isolating contacts are inclined. A high-speed solenoid valve 15 is fixedly connected to the bottom of the arc-extinguishing medium chamber 10. An inert gas storage tank 14 is inserted into the front of the arc-extinguishing medium chamber 10. A fixing plug 17 is threaded onto the outer side of the inner wall of the arc-extinguishing medium chamber 10, and the fixing plug 17 abuts against the front of the inert gas storage tank 14. The inert gas storage tank 14 is inserted and fixedly connected to the air inlet of the high-speed solenoid valve 15. The outlet of the high-speed solenoid valve 15 is connected to multiple arc-extinguishing nozzles 9 and a physical isolation unit through a gas distribution valve 16. When the central controller module detects an arc fault signal, it immediately sends a signal to the high-speed solenoid valve 15. Upon receiving the activation command, the ultra-high-speed solenoid valve 15 opens rapidly, allowing the high-pressure inert gas in the inert gas storage tank 14 to be quickly and evenly distributed to each arc-extinguishing nozzle 9 through the gas distribution valve 16. The high-pressure inert gas ejected from the arc-extinguishing nozzle 9 forms a powerful airflow that directly impacts the contact points of the moving and stationary contacts and the wiring positions of the isolating contacts of the electrical component circuit breaker. This high-pressure inert gas can reduce the temperature around the arc and weaken its energy in a very short time. At the same time, the inert gas can rapidly dilute and disperse the oxygen and other combustion-supporting gases around the arc, destroying the necessary conditions for the arc to maintain combustion, thereby effectively suppressing and extinguishing the arc.

[0062] If the arc is not extinguished within 15-30ms and the arc detector 6 can still detect the arc signal, the gas distribution valve 16 connects the output of the ultra-high speed solenoid valve 15 and the physical isolation unit to isolate the fault area from the normal area, preventing the further spread of the arc and the impact of the fault. This isolation can not only avoid damage to other electrical components around the fault, but also create safe conditions for subsequent inspection and maintenance.

[0063] Reference Figure 5The gas distribution valve 16 is connected to multiple arc-extinguishing nozzles 9 via an internal pipeline, and each arc-extinguishing nozzle 9 is connected to a branch of the internal pipeline via an independent shut-off valve 18. The independent shut-off valve 18 allows the operating state of each arc-extinguishing nozzle 9 to be controlled individually. In actual operation, the independent shut-off valve 18 can be manually opened and closed according to whether electrical components are installed in the orientation of the arc-extinguishing nozzle 9, ensuring that only the arc-extinguishing nozzle facing the location where electrical components are present and arc faults may occur will spray the arc-extinguishing medium, avoiding unnecessary medium waste. The physical isolation unit includes a power base 11 and an isolation element terminal block 12. The isolation element terminal block 12 is provided with a terminal block 13. The electrical components on the electrical component mounting bracket 3 are all connected to the busbar and... The output cable has expansion lifting rubber bladders 20 embedded at the upper ends of both sides of the power base 11. The tops of the expansion lifting rubber bladders 20 abut against the bottom sides of the isolation element terminal block 12. A square groove is formed in the center of the power base 11, and a fuse connecting bar 21 is set in the center of the square groove. Multiple fuse protectors are set in the fuse connecting bar 21 corresponding to multiple connected lines. Multiple power plugs 19 are fixedly connected to the bottom of the isolation element terminal block 12, and the multiple power plugs 19 are electrically connected to multiple terminals on the terminal block 13. The multiple power plugs 19 are inserted into the fuse protector isolation contacts in the fuse connecting bar 21 in pairs. The side of the expansion lifting rubber bladders 20 facing inward is connected to the square groove in the center of the power base 11 through a throttling valve. Multiple through-jet nozzles are evenly distributed at the bottom of the terminals 13 corresponding to the isolation element terminal block 12. When the central controller module detects an arc fault and fails to extinguish the arc within the specified time, the gas distribution valve 16 introduces high-pressure inert gas into the expansion lifting rubber bladder 20, causing the expansion lifting rubber bladder 20 to gradually expand. The expansion lifting rubber bladder 20 lifts the isolation element terminal block 12, causing the power connector 19 to be pulled out from the fuse protection isolation contact in the fuse connecting bar 21, thereby cutting off the connection between the electrical component and the busbar and output cable, achieving physical isolation. At the same time, the high-pressure inert gas is injected into the central square groove of the power base 11 through the throttle valve on the expansion lifting rubber bladder 20, forming a gap between the isolation element terminal block 12 and the power base 11. An air curtain further enhances the isolation effect, preventing the spread of arcing and faults. This physical isolation method can not only quickly cut off faulty circuits, but also form an additional protective barrier using gas jets, improving the reliability of isolation. Furthermore, the design of this physical isolation unit also considers the convenience of fault recovery. After the fault is cleared, simply manually press the isolating element terminal block 12 to squeeze out the residual gas in the expansion lifting rubber bladder 20, and re-insert the power plug 19 into the fuse protector's isolating contact to restore the circuit connection. This eliminates the need for complex operations and replacing numerous parts, significantly shortening fault repair time and improving the operating efficiency and stability of the high-voltage switchgear in thermal power plants. The arc detector 6 is an ultraviolet light sensor with a solar-blind filter cover at the bottom.Furthermore, a reflector 4 is fixedly connected to the back side of the cabinet door 2, corresponding to the position of the electrical component mounting bracket 3. Multiple condensing reflectors 5 are evenly distributed inside the reflector 4, and these condensing reflectors 5 are an array of tilted reflectors used to reflect the light from the arc point on the electrical component mounting bracket 3 towards the ultraviolet sensor sensing position of the arc detector 6. The response wavelength of the solar-blind filter is strictly limited to the "solar blind zone" of 240-280nm to completely isolate interference from ambient light, making the arc detector 6 sensitive only to ultraviolet light in the corresponding wavelength band of the arc. This significantly improves the accuracy and reliability of arc detection. The tilted reflector array composed of condensing reflectors 5 effectively reflects and focuses the arc light generated at various positions on the electrical component mounting bracket 3 onto the ultraviolet sensor sensing position of the arc detector 6. Even if the arc occurs in a relatively concealed location or where light propagation is obstructed, the arc light can still reach the arc detector 6 smoothly through the reflection of the condensing reflectors 5, greatly increasing the range and sensitivity of arc detection.

[0064] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0065] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or arc fault rapid isolation protection device for high-voltage switchgear in a thermal power plant that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or arc fault rapid isolation protection device for high-voltage switchgear in a thermal power plant.

[0066] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0067] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A rapid isolation protection device for arc faults in a high-voltage switchgear of a thermal power plant, comprising a high-voltage switch unit cabinet (1), wherein a cabinet door (2) is hinged to the front side of the high-voltage switch unit cabinet (1), and an electrical component mounting bracket (3) is fixedly connected to the back side of the inner cavity of the high-voltage switch unit cabinet (1), wherein electrical components are mounted on the electrical component mounting bracket (3), and the electrical components are connected to a busbar through isolation contacts, characterized in that: An arc detector (6) is fixedly installed at the top center of the high voltage switch unit cabinet (1), and an ultrasonic sensor (7) is fixedly installed inside the high voltage switch unit cabinet (1). Multiple ultrasonic sensors (7) are evenly distributed around the arc detector (6). The arc detector (6) and the ultrasonic sensor (7) are electrically connected to a central controller module via a data line. The central controller module has a preset protection logic and a synchronous timing unit. Multiple ultrasonic sensors (7) are fixedly installed in a non-collinear geometric distribution within the internal space of the switch cabinet; The high-voltage switch unit cabinet (1) is equipped with a fast isolation protection module. The fast isolation protection module includes an active arc extinguishing suppression unit and a physical isolation unit. The active arc extinguishing suppression unit is used to spray arc extinguishing medium toward the calculated fault point coordinates. The physical isolation unit is used to drive the busbar connection of electrical components to separate and isolate the power supply to form a physical isolation barrier.

2. The rapid isolation and protection device for arc flash faults in high-voltage switchgear of thermal power plants according to claim 1, characterized in that: The synchronization timing unit is used to provide a uniform high-precision timestamp for all ultrasonic sensors (7). At least one ultrasonic sensor (7) is installed on the inside of the top panel of the switch cabinet, and at least two ultrasonic sensors (7) are installed on the inside of adjacent vertical side panels respectively.

3. The rapid isolation and protection device for arc flash faults in high-voltage switchgear of thermal power plants according to claim 2, characterized in that: The synchronization timing unit adopts a GPS / BeiDou dual-mode timing module to provide a unified microsecond-level clock synchronization signal for the central controller module and the timing circuit in each ultrasonic sensor (7), ensuring that the timestamps generated by each ultrasonic sensor (7) are based on the same time reference.

4. The rapid isolation and protection device for arc faults in high-voltage switchgear of thermal power plants according to claim 3, characterized in that: The ultrasonic sensor (7) is a broadband acoustic emission sensor, and each ultrasonic sensor (7) has a built-in signal preprocessing circuit for amplifying and bandpass filtering the original vibration signal. The ultrasonic sensor (7) is equipped with a leading edge detection circuit for generating a trigger pulse with a precise timestamp when the pressure wave signal first exceeds the threshold.

5. A rapid isolation and protection device for arc flash faults in high-voltage switchgear of thermal power plants according to claim 4, characterized in that: The protection logic within the central controller module specifically includes the following steps: S1: Continuously monitor the signal of the arc detector (6). Once the first trigger signal is received, immediately start high-speed data acquisition and record the original waveform data and timestamp sequence of each ultrasonic sensor (7) from this moment on. S2: For the first arriving pressure wave signal, that is, the signal that first arrives at any ultrasonic sensor (7), perform waveform feature analysis to verify whether it has the typical characteristics of an electric arc pressure wave. S3: From the recorded time series data, accurately extract the times T1, T2, T3... when the pressure wave front arrives at at least three non-collinear ultrasonic sensors (7); S4: Based on the known spatial coordinates (Si(x,y,z)) of each ultrasonic sensor (7) and the propagation speed v of the pressure wave in the medium inside the switch cabinet, the fault point coordinates P(x,y,z) that satisfy the equation set "distance difference = propagation speed × time difference" are solved using the time difference positioning algorithm. S5: Compare the calculated fault point coordinates P with the coordinates of the "fault danger area" defined in the three-dimensional digital model of the switchgear pre-stored in the central controller module; S6: If P is located within the "fault danger zone", it is determined to be a confirmed arcing fault inside the cabinet. Without any delay, a trip command and isolation protection command will be issued immediately. If P is located outside the zone, it is determined to be external interference or non-fault discharge. An alarm will be activated but the circuit will not trip.

6. A rapid isolation and protection device for arc faults in high-voltage switchgear of thermal power plants according to claim 5, characterized in that: The protection logic within the central controller module also includes self-verification and anti-interference steps: During normal operation, the central controller module periodically issues a self-verification command, generates a simulated pressure wave through a miniature calibration sound source installed in the non-hazardous area of ​​the high-voltage switch unit cabinet (1), and each ultrasonic sensor (7) receives the calibration signal. The central controller module calculates the arrival time difference of the calibration signal, inverts the actual propagation speed v' of the pressure wave in real time, and dynamically corrects the speed parameter v in the positioning algorithm to compensate for the change in sound speed caused by the temperature and gas density changes of the high-voltage switch unit cabinet (1).

7. A rapid isolation and protection device for arc flash faults in high-voltage switchgear of thermal power plants according to claim 6, characterized in that: The active arc extinguishing suppression unit includes an arc extinguishing jet (8) and an arc extinguishing medium chamber (10). The arc extinguishing jet (8) is fixedly installed on the front end of the inner wall of the high voltage switch unit cabinet (1), and the arc extinguishing medium chamber (10) is fixedly installed on the lower end of the high voltage switch unit cabinet (1). The arc-extinguishing jet row (8) is fixedly connected to multiple arc-extinguishing nozzles (9) on its inner side, and the nozzle outlet of the arc-extinguishing nozzle (9) is inclined toward the junction of the moving and stationary contacts of the electrical component circuit breaker and the wiring position of the isolating contact on the electrical component mounting bracket (3); The arc-extinguishing medium chamber (10) has an internal hollow structure. A high-speed electromagnetic valve (15) is fixedly connected to the bottom of the inner cavity of the arc-extinguishing medium chamber (10). An inert gas storage tank (14) is inserted into the front side of the arc-extinguishing medium chamber (10). A fixed compression plug (17) is threadedly connected to the outer side of the inner wall of the arc-extinguishing medium chamber (10). The fixed compression plug (17) abuts against the front side of the inert gas storage tank (14). The bottle mouth of the inert gas storage tank (14) is inserted and fixedly connected to the air inlet of the high-speed electromagnetic valve (15). The air outlet of the high-speed electromagnetic valve (15) is connected to multiple arc-extinguishing nozzles (9) and physical isolation units through a gas distribution valve (16).

8. A rapid isolation and protection device for arc flash faults in high-voltage switchgear of thermal power plants according to claim 7, characterized in that: The gas distribution valve (16) is connected to multiple arc-extinguishing nozzles (9) through an internal pipeline, and the multiple arc-extinguishing nozzles (9) are connected to branches of the internal pipeline through independent shut-off valves (18).

9. A rapid isolation and protection device for arc flash faults in high-voltage switchgear of thermal power plants according to claim 7, characterized in that: The physical isolation unit includes a power base (11) and an isolation element terminal block (12). The power base (11) is installed on the upper end of the arc extinguishing medium chamber (10), and the isolation element terminal block (12) is installed on the upper end of the power base (11). The isolation element terminal block (12) is provided with a terminal block (13). The electrical components on the electrical component mounting bracket (3) are all connected to the busbar and output cable through the terminal block (13). The upper ends of both sides of the power base (11) are embedded with expansion lifting rubber bladders (20), and the top of the expansion lifting rubber bladders (20) abuts against the bottom of both sides of the isolation element terminal block (12). The center of the power base (11) is provided with a square groove, and a fuse connection bar (21) is provided in the center of the square groove. A fuse protector is provided in the fuse connection bar (21) corresponding to multiple connecting lines. A number of power plugs (19) are fixedly connected to the bottom of the isolation element terminal block (12), and the multiple power plugs (19) are electrically connected to multiple terminals on the terminal block (13). The multiple power plugs (19) are inserted into the fuse protector isolation contacts in the fuse connection bar (21) in pairs. The expansion lifting rubber bladders (20) on both sides are connected to the square groove in the center of the power base (11) through a throttle valve on the inward side. A number of through injection ports are evenly provided on the bottom of the terminal block (13) corresponding to the isolation element terminal block (12).

10. The method for breaking the arch in a rapid isolation protection device for arc faults in a high-voltage switchgear of a thermal power plant according to claim 9, characterized in that: The arc detector (6) is an ultraviolet light sensor structure with a solar-blind filter cover at the bottom. A reflector (4) is fixedly connected to the back of the cabinet door (2) corresponding to the position of the electrical component mounting bracket (3). Multiple condensing reflectors (5) are evenly distributed on the inner side of the reflector (4). The condensing reflectors (5) are an array of reflectors mounted at an angle, used to reflect the light from the arc light generation point on the electrical component mounting bracket (3) toward the ultraviolet light sensor sensing position of the arc detector (6).

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