A power supply system and power converter

Abstract

The application provides a power supply system and a power converter, which are applied to a photovoltaic power station and an energy storage power station collection system. The power supply system comprises a station controller and a plurality of sub-arrays, each of which comprises a plurality of power converters and a sub-array data acquisition unit. The power converter is used to convert direct current from a photovoltaic module or an energy storage device into alternating current and input the alternating current into a power grid. The power converter is also used to upload recording wave data of the power grid failure through a communication interface to the sub-array data acquisition unit, and the recording wave data comprises voltage and output current information of the power converter. The sub-array data acquisition unit is used to collect and upload the recording wave data of the power grid failure uploaded by the plurality of power converters in the sub-array where the sub-array data acquisition unit is located. The station controller is used to collect and store the recording wave data of the power grid failure uploaded by the plurality of sub-array data acquisition units. According to the scheme, the collection time of the fault recording wave file can be reduced, and the ability and efficiency of the power grid fault analysis report can be improved.

Description

Technical Field

[0001] This application relates to the field of power technology, and more specifically, to a power supply system and a power converter. Background Technology

[0002] Automatic fault recording in power systems has become a crucial basis for analyzing system accidents, particularly the behavior of relay protection systems. Fault waveform recording, in particular, is a power grid fault diagnosis system based on fault waveform information. It automatically and accurately records changes in electrical quantities before and after a fault occurs in the power grid. By analyzing and comparing these electrical quantities, various fault points can be accurately located and quickly eliminated, effectively improving the safe operation level of the power system. However, currently, when a power grid fault occurs, the fault waveform recording device generates waveform files and stores them at the power converter. Maintenance personnel need to travel to the site of each device, acquire the fault waveform files separately using digital acquisition equipment, export logs during inspections, summarize all fault waveform data, and then have professional technicians manually analyze the data to locate the fault point and cause, enabling maintenance personnel to repair and eliminate the fault. With the increasing coverage and number of devices in the power system, collecting fault waveform data from various devices for fault analysis and elimination consumes a significant amount of time, resulting in long power restoration times and wasted human and material resources. Therefore, improving the efficiency of fault waveform analysis is a problem that needs to be solved. Summary of the Invention

[0003] This application provides a power supply system and a power converter that detects faults and records waveform data, which is then uploaded in real time. The fault waveform data is reported level by level, enabling overall fault waveform analysis at the power plant level. This reduces the time required for manual inspection and log export, as well as for professional technicians to analyze power grid events. It facilitates rapid location of the causes of power grid events and improves the capability and efficiency of power grid fault analysis reports.

[0004] In a first aspect, this application provides a power supply system comprising a station controller and multiple subarrays. Each subarray includes multiple power converters and a subarray data acquisition unit. The power converters convert direct current (DC) from photovoltaic modules or energy storage devices into alternating current (AC) and input it into the power grid. Each power converter includes an output terminal and a communication interface. The power converter also uploads waveform data recorded during a power grid fault to the subarray data acquisition unit within its subarray via the communication interface. The waveform data includes voltage and current information output from the power converter's output terminal. The subarray data acquisition unit collects and uploads waveform data recorded during a power grid fault uploaded by multiple power converters within its subarray. The station controller collects and stores the waveform data uploaded by multiple subarray data acquisition units during a power grid fault.

[0005] The power converter includes a photovoltaic inverter and an energy storage converter, which are used to convert the direct current (DC) power supplied by the photovoltaic modules and energy storage devices into alternating current (AC), and then supply the AC power to the power grid. It is worth noting that the power supply system provided in this application can be a pure photovoltaic system (i.e., the power converter only includes a photovoltaic inverter), a pure energy storage system (i.e., the power converter only includes an energy storage converter), or a photovoltaic-energy storage system (i.e., the power converter includes both an energy storage converter and a photovoltaic inverter).

[0006] The power converter features fault detection and fault recording capabilities. When it detects a grid fault, such as undervoltage ride-through or overvoltage ride-through, it automatically enters recording mode and records the waveform data. The power converter uploads the recorded data promptly without occupying local storage space, thus reducing the resource consumption of the power converter chip.

[0007] In a power supply system, the AC outputs of multiple power converters within the same subarray are connected to the same prefabricated substation. The subarray data acquisition unit can be located within the prefabricated substation and connected to the communication interface of the power converters to achieve communication. Multiple power converters upload waveform data to the subarray data acquisition unit in real time. After collecting the waveform data uploaded by multiple power converters within the subarray, the subarray data acquisition unit uploads the waveform data from these power converters to the station controller. The station controller performs comprehensive control and management of the power converters in each subarray of the power supply system. The station controller collects and stores waveform data uploaded by multiple subarray data acquisition units when grid faults occur. The station controller acquires waveform data recorded by all power converters in the power supply system, enabling station-level fault waveform file storage, which can then be directly viewed and analyzed.

[0008] In existing technologies, when a grid fault occurs, the output voltage or current of the power converter changes. Although the power converter can record its own output voltage and current information, due to the distributed configuration of the power converters, it is difficult to compare the fault response of different power converters based on the fault waveform data recorded by a single power converter. The power converter in this application reports fault waveform data level by level and collects all fault waveform data at the station controller. It makes full use of the string power supply system architecture, eliminating the need for additional waveform recording equipment, and realizes overall fault waveform recording storage and analysis at the station level. At the station controller, the output voltage and output current of each power converter can be obtained, and the fault response of different devices can be compared.

[0009] Currently, maintenance personnel can use digital acquisition devices to read fault recording files one by one from the fault recording equipment of power converters, and then analyze all the recording files to accurately locate the fault point based on the fault recording data, eliminate the power grid fault, and restore system operation as soon as possible. However, with the increase in the scale of power supply systems and power grids, the probability of accidents caused by local power grid faults and the probability of the affected area expanding have also greatly increased. At the same time, the increasing number of devices in the power supply system has also greatly increased the amount of information generated by the power grid when a fault occurs, which objectively increases the time required for maintenance personnel to collect fault recording data, handle faults, and restore power supply. Therefore, this application obtains fault recording data of all power converters through the station controller, which can effectively reduce the time spent on manual inspection and log export and professional technicians analyzing power grid events. At the same time, storing all fault recording data in a unified manner can reduce the local storage space of power converters and save manpower and resources.

[0010] In one implementation, the waveform data also includes the first moment when the power converter starts recording and the second moment when the power grid fails. When the waveform data uploaded by multiple power converters in the subarray includes different first moments or different second moments, the subarray data acquisition unit is used to unify the first moment and the second moment so that the waveform data uploaded by the subarray data acquisition unit to the station controller of multiple power converters includes the same first moment and the same second moment.

[0011] Multiple power converters record waveform data according to their respective system times. The output voltage and current information in the waveform data includes corresponding time information. The waveform data also includes the first moment when the power converter starts recording and the second moment when it ends recording. After collecting the waveform data from multiple power converters within the subarray, the subarray data acquisition unit needs to perform time synchronization. Waveform data time synchronization ensures that the time of the event data recorded by multiple power converters is consistent. When multiple power converters simultaneously record event fault data, ensuring the time consistency of this data helps to better compare and analyze the data, improving data consistency and comparability.

[0012] According to the scheme in this application, the waveform recording data of multiple power converters is synchronized to ensure the accuracy and reliability of the waveform recording data. Accurate waveform recording data synchronization can effectively help analyze power grid events and diagnose faults.

[0013] In one implementation, the subarray data acquisition unit is also used to generate a subarray analysis report. The subarray analysis report is used to characterize the waveform data uploaded by multiple power converters in the subarray where the subarray data acquisition unit is located. The subarray analysis report includes fault types, which are used to indicate at least one of the following: single-phase short circuit, two-phase short circuit, three-phase short circuit, high-voltage operation, phase loss operation, or grid tripping.

[0014] The subarray data acquisition unit determines the type of fault based on the waveform and characteristics of the fault recording data, including single-phase short circuit, two-phase short circuit, three-phase short circuit, high-voltage operation, phase loss operation, or grid tripping. This fault type can be determined by analyzing the status displayed on the fault recording data. The subarray analysis report can be used to display the analysis results of the recording data within the subarray.

[0015] According to the scheme of this application, the subarray data acquisition unit has the ability to automatically generate power grid fault analysis reports. After quickly analyzing the fault waveform data, the analysis results are presented intuitively in the form of a report, which helps to improve the ability of power grid fault analysis reports, quickly analyze fault types, and facilitates earlier power restoration.

[0016] In one implementation, the station controller is also used to generate a station-level analysis report, which characterizes the waveform data uploaded by multiple subarray data acquisition units. The station-level analysis report includes location information, which indicates whether the fault occurs within or outside the power supply system.

[0017] After collecting waveform data uploaded by multiple subarray data acquisition units, the station controller can automatically generate a station-level analysis report based on the fault waveform data uploaded by each subarray. The station controller can use preset algorithms or models to determine whether the fault occurred within or outside the station based on the differences in the fault waveform data recorded by different subarrays.

[0018] According to the solution in this application, the station controller has the ability to automatically generate power grid fault analysis reports. After quickly analyzing the fault recording data, the analysis results are presented intuitively in the form of a report, which helps to improve the ability of power grid fault analysis reports, quickly locate faults, and facilitate earlier power restoration.

[0019] In one implementation, the station-level analysis report also includes a fault type, which indicates at least one of the following: single-phase short circuit, two-phase short circuit, three-phase short circuit, high-voltage operation, phase loss operation, or grid tripping.

[0020] The station controller determines the type of fault based on the waveform and characteristics of the fault recording data, including single-phase short circuit, two-phase short circuit, three-phase short circuit, high-voltage operation, phase loss operation, or grid tripping. This fault type can be determined by analyzing the status displayed on the fault recording data. The station-level analysis report can be used to display the analysis results of the recording data within the power station.

[0021] According to the solution in this application, the station controller has the ability to automatically generate power grid fault analysis reports. After quickly analyzing the fault recording data, the analysis results are presented intuitively in the form of a report, which helps to improve the ability of power grid fault analysis reports, quickly analyze fault types, and facilitates earlier power restoration.

[0022] In one implementation, when the waveform data uploaded by the power converter in the subarray where the subarray data acquisition unit is located exceeds a first preset ratio, indicating an asymmetrical drop in the three-phase voltage of the power grid, and the positive sequence voltage of the power grid is lower than 0.9 per unit and not lower than 0.5 per unit during the three-phase voltage drop, the fault type indicates that a single-phase short circuit has occurred in the power grid, and the first preset ratio is greater than or equal to 80% and less than or equal to 100%.

[0023] For example, the first preset ratio can be set to 90%.

[0024] When more than a first preset proportion of power converters in the subarray where the data acquisition unit is located records an asymmetrical drop in the three-phase voltage of the power grid, that is, an unbalanced decrease in the amplitude or phase of the three-phase voltage of the power grid, or a decrease in the voltage of some phases of the three-phase voltage of the power grid while others do not decrease or even increase, and during the asymmetrical drop in the three-phase voltage of the power grid, the positive sequence voltage of the three-phase voltage of the power grid is lower than 0.9 per unit and not lower than 0.5 per unit, a single-phase short-circuit fault is determined to have occurred in the power grid.

[0025] In one implementation, when the waveform data uploaded by the power converter in the subarray where the subarray data acquisition unit is located exceeds the first preset ratio indicates that the three-phase voltage of the power grid is asymmetrically dropped, and the positive sequence voltage of the power grid is lower than 0.4 per unit during the three-phase voltage drop, the fault type indicates that the power grid has a two-phase short circuit, and the first preset ratio is greater than or equal to 80% and less than or equal to 100%.

[0026] When more than a first preset ratio of power converters in the subarray where the data acquisition unit is located records a three-phase voltage asymmetry drop in the power grid, and during the three-phase voltage asymmetry drop, the positive sequence voltage of the three-phase voltage of the power grid is lower than 0.4 per unit, it is determined that a two-phase short-circuit fault has occurred in the power grid.

[0027] In one implementation, when the waveform data uploaded by the power converter in the subarray where the subarray data acquisition unit is located is greater than the first preset ratio, it indicates that the three-phase voltage of the power grid has symmetrically dropped, and the positive sequence voltage of the power grid is lower than 0.9 per unit during the three-phase voltage drop, the fault type indicates that the power grid has a three-phase short circuit, and the first preset ratio is greater than or equal to 80% and less than or equal to 100%.

[0028] When more than a first preset proportion of power converters in the subarray where the data acquisition unit is located record a symmetrical drop in the three-phase voltage of the power grid, and during the symmetrical drop in the three-phase voltage of the power grid, the positive sequence voltage of the three-phase voltage of the power grid is lower than 0.9 per unit, it is determined that a three-phase short circuit fault has occurred in the power grid.

[0029] According to the scheme in this application, the specific faults occurring in the power grid can be determined based on the different characteristics of the three-phase voltage of the power grid recorded by the fault waveform data. This is beneficial to improving the ability of power grid fault analysis reports, quickly analyzing fault types, and facilitating earlier power restoration.

[0030] In one implementation, when the waveform data uploaded by the subarray data acquisition unit indicates that the subarray data acquisition unit has recorded at least one of the following faults in the power grid: single-phase short circuit, two-phase short circuit, three-phase short circuit, high-voltage operation, phase loss operation, or power grid tripping, and none of the subarray data acquisition units have recorded a power grid tripping fault, and the location information indicates that the fault occurred outside the power supply system, the second preset ratio is greater than or equal to 80% and less than or equal to 100%. For example, the second preset ratio can be set to 90%.

[0031] When a fault occurs at different locations in the power grid and power supply system, the three-phase voltage of the power grid recorded by the power converter in the subarray where the subarray data acquisition unit is located will have different characteristics. Based on the different fault waveform data uploaded by different subarrays, the location of the fault can be determined.

[0032] Of the waveform data uploaded by all subarray data acquisition units collected by the station controller, more than a second preset proportion of subarray data acquisition units recorded a single-phase short-circuit fault in the power grid, while no subarray data acquisition unit recorded a power grid trip. At this time, the location information indicates that the single-phase short-circuit fault occurred outside the power supply system.

[0033] In one implementation, when the waveform data uploaded by the subarray data acquisition unit indicates that at least one of the following occurs in the power grid: single-phase short circuit, two-phase short circuit, three-phase short circuit, high-voltage operation, or phase loss operation, and after the fault ends, a subarray data acquisition unit with a ratio less than a third preset ratio records a power grid tripping fault, the location information indicates that the fault occurred within the power supply system. The second preset ratio is greater than or equal to 80% and less than or equal to 100%, and the third preset ratio is greater than or equal to 40% and less than or equal to 60%.

[0034] For example, the third preset ratio can be set to 50%.

[0035] If, among the waveform data uploaded by all subarray data acquisition units collected by the station controller, more than a second preset proportion of subarray data acquisition units record at least one of the following: single-phase short circuit, two-phase short circuit, three-phase short circuit, high-voltage operation, or phase loss operation, and after the fault ends, at least one subarray data acquisition unit records a grid trip, and the proportion of subarray data acquisition units recording a grid trip is less than a third preset proportion, then the location information indicates that the fault occurred within the power supply system, specifically on the tie line of the subarray where the subarray data acquisition unit that recorded the grid trip is located.

[0036] According to the scheme in this application, the location information of the fault can be determined based on the fault characteristics recorded in the fault waveform data in different subarrays. This is beneficial to improving the ability of power grid fault analysis reports, quickly analyzing fault types, and facilitating earlier power restoration.

[0037] Secondly, this application provides a power converter for a power supply system. The power supply system includes a station controller and multiple subarrays, each subarray including a power converter and a subarray data acquisition unit. The power converter converts direct current (DC) from photovoltaic modules or energy storage devices into alternating current (AC) and inputs it into the power grid. The power converter includes an output terminal and a communication interface. The power converter also uploads waveform data recorded during a power grid fault to the subarray data acquisition unit of the subarray containing the power converter via the communication interface. The waveform data includes voltage and current information output from the power converter's output terminal. The power converter uploads the waveform data recorded during a power grid fault to the subarray data acquisition unit, which then further uploads the waveform data recorded during a power grid fault to the station controller.

[0038] Other beneficial effects can be found in the description of the first aspect, and will not be repeated here. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of an application scenario provided in this application;

[0040] Figure 2 This is a schematic diagram illustrating the hierarchical reporting of fault recording data provided in an embodiment of this application;

[0041] Figure 3 This is a schematic diagram of the fault recording process provided in the embodiments of this application. Detailed Implementation

[0042] The technical solutions in this application will now be described in conjunction with the accompanying drawings. The detailed descriptions and drawings of the following embodiments are used to exemplarily illustrate the principles of this application, but should not be used to limit the scope of this application; that is, this application is not limited to the described embodiments.

[0043] The power supply system provided in this application can be applied to various fields, including new energy smart microgrids, power transmission and distribution, new energy fields (such as photovoltaic grid-connected fields, thermal power grid-connected fields, or wind power grid-connected fields), photovoltaic power generation, wind power generation, thermal power generation, and high-power converter fields (such as converting DC power to high-power high-voltage AC power). The specific application scenario can be determined accordingly, and no limitations are imposed here. The power supply system provided in this application can be applied to photovoltaic power supply systems and wind power supply systems without limitation. The power supply system provided in this application can be adapted to different application scenarios, such as powering loads in photovoltaic-storage power supply environments, powering loads in wind-storage power supply environments, powering loads in pure energy storage power supply environments, or other application scenarios.

[0044] Current new energy and energy storage power stations are generally composed of multiple power electronic devices that step up and combine voltages in stages. When a grid fault occurs, it is desirable to record the output voltage and current of each power electronic device to provide analytical input for further grid fault analysis. Fault recording is a key technology in power systems, primarily used for real-time monitoring, recording, and analysis of fault events in the power grid. By capturing voltage and current waveforms and related data under abnormal grid conditions, it helps maintenance personnel quickly locate problems, analyze fault causes, and take appropriate maintenance measures. Fault recording is widely used in the power industry, significantly improving the operational reliability of the power grid and serving as one of the guarantees for the safe and stable operation of the power system.

[0045] When a power grid fault occurs, each power converter records fault waveforms, generating fault waveform files which are then stored at each device. Maintenance personnel must travel to the site of each device and acquire these files individually using digital acquisition equipment. After exporting logs during inspections, all fault waveform data is compiled, and then professional technicians manually analyze the data to locate the fault point and cause, enabling maintenance personnel to repair and resolve the fault. Due to the increasing size of power supply systems and grids, and the growing number of devices, collecting fault waveform data from each device for fault analysis and troubleshooting consumes a significant amount of time, resulting in prolonged power restoration times and a waste of considerable human and material resources.

[0046] Based on the above problems, this application provides a power supply system that detects faults and records waveform data through a power converter, uploads the data in real time, and reports the fault waveform data level by level, realizing overall fault waveform analysis at the power station level. This reduces the time required for manual inspection to export logs and for professional technicians to analyze power grid events, facilitates rapid location of the cause of power grid events, and improves the capability and efficiency of power grid fault analysis reports.

[0047] Figure 1 The illustration shows an application scenario of an embodiment of this application. This application can be applied to... Figure 1The power supply system shown.

[0048] The power supply system 100 includes a station controller 41 and multiple subarrays. Each subarray includes multiple power converters 20 and a subarray data acquisition unit 31. Photovoltaic modules 11 and energy storage devices 12 are used to connect to the power grid 50 via the power converters 20. The power converters 20 convert the direct current from the photovoltaic modules 11 or the energy storage devices 12 into alternating current and input it into the power grid 50. The power converters 20 include an output terminal and a communication interface connected to the subarray data acquisition unit 31.

[0049] In one application scenario, the power supply system 100 is a photovoltaic power supply system, and the power converter 20 is a photovoltaic inverter 21. The photovoltaic inverter 21 is connected to the photovoltaic module 11 and is used to convert the DC power transmitted by the photovoltaic module 11 into AC power, and then transmit the AC power to the prefabricated substation 30. After the prefabricated substation 30 boosts the AC power, the boosted AC power is further boosted by the booster station 40 before being transmitted to the power grid 50.

[0050] In another application scenario, the power supply system 100 is an energy storage power supply system, and the power converter 20 is an energy storage converter 22 (power control system, PCS). The energy storage converter 22 is connected to the energy storage device 12 and is used to convert the DC power supplied by the energy storage device 12 into AC power, and then transmit the AC power to the prefabricated substation 30. The prefabricated substation 30 boosts the AC power and then transmits the boosted AC power to the power grid 50 via a step-up substation 40. The prefabricated substation 30, connected to the energy storage converter 22, can also step down the AC power from the power grid and transmit the stepped-down AC power to the energy storage converter 22. The energy storage converter 22 converts the AC power into DC power and then transmits the DC power to the energy storage device 12 for storage. The energy storage device 12 can be a large-capacity, high-power battery, an energy storage container, or other forms of energy storage device. The energy storage device 12 can be a secondary battery.

[0051] In another application scenario, the power supply system 100 is a photovoltaic-storage system, and the power converter 20 includes a photovoltaic inverter 21 and an energy storage converter 22. The photovoltaic-storage system includes photovoltaic modules 11, photovoltaic inverter 21, energy storage converter 22, energy storage device 12, prefabricated substation 30, and step-up substation 40. The photovoltaic-storage system also includes a power grid 50 and loads (not shown in the figure). The photovoltaic inverter 21 can convert the direct current (DC) from the photovoltaic modules 11 into alternating current (AC) and supply the AC power to the AC power grid 50 or the load. Alternatively, the photovoltaic inverter 21 can supply the DC power from the photovoltaic modules 11 to the energy storage device 12 to charge it. The energy storage device 12 in the photovoltaic-storage system can store and release electrical energy. The energy storage device 12 stores the DC power from the photovoltaic modules 11 and also supplies power to the power grid 50 or the load through the photovoltaic inverter 21. The photovoltaic inverter 21 includes two DC ports and an AC output port. The two DC ports are used to connect the photovoltaic module 11 and the energy storage device 12, respectively. The AC output port can be used to output AC power, which is distributed through a distribution box. The photovoltaic module 11 supplies power to the grid 50 and the load through the DC ports. The energy storage device 12 supplies power to the load through the DC ports.

[0052] In its implementation, the power supply system 100 includes multiple energy storage subarrays or multiple photovoltaic subarrays. Each energy storage subarray includes at least one energy storage device 12, which is connected to the DC input terminal of an energy storage converter 22. Each photovoltaic subarray includes at least one photovoltaic module 11, which is connected to the DC input terminal of a photovoltaic inverter 21.

[0053] Figure 2 and Figure 3 This illustration shows a schematic diagram of the step-by-step reporting of waveform data provided in an embodiment of this application.

[0054] like Figure 2 and Figure 3 As shown, the power converter 20 is also used to upload the waveform data when the power grid 50 fails to the subarray data acquisition unit 31 of the subarray where the power converter is located through the communication interface. The waveform data includes the voltage and output current information output by the output terminal of the power converter 20.

[0055] Power converter 20 converts the DC power supplied by power supply unit 10 into AC power and supplies the AC power to power grid 50. Since power converters 20 are connected in parallel throughout the power supply system 100, the output voltage or output current of power converter 20 will change when a fault occurs in power grid 50. Power converter 20 has fault detection and fault recording functions. When power converter 20 detects a fault in power grid 50, or when the power supply system experiences low voltage ride-through (LVRT) or high voltage ride-through (HVRT), power converter 20 automatically enters the recording state and records the waveform data.

[0056] The fault recording file is triggered by a fault in the power supply system 100 or the power grid 50. The power converter 20 collects various analog and digital signals from the power system. The recorded data includes, but is not limited to, output voltage, output current, or power. The recorded data also includes analog quantities such as AC three-phase grid voltage, three-phase current, and DC bus voltage, as well as information such as fault occurrence time, fault code, high-voltage ride-through, and low-voltage ride-through. The power converter 20 can choose not to store the recorded data but can upload it promptly, without occupying local storage space, thus reducing the resource consumption of the power converter 20 chip.

[0057] See also Figure 2 and Figure 3 The subarray data acquisition unit 31 is used to collect and upload waveform data uploaded by multiple power converters 20 in the subarray where the subarray data acquisition unit 31 is located when the power grid 50 fails.

[0058] In the power supply system 100, the AC output terminals of multiple power converters 20 within the same subarray are connected to the same prefabricated substation 30. The subarray data acquisition unit 31 can be located in the prefabricated substation 30 and connected to the power converters 20 to achieve communication. Multiple power converters 20 upload waveform data to the subarray data acquisition unit 31 in real time. After collecting the waveform data uploaded by multiple power converters 20 within the subarray, the subarray data acquisition unit 31 uploads the waveform data to the station controller 41.

[0059] In one embodiment, the communication port of the power converter 20 is connected to the subarray data acquisition unit 31 via power line carrier (PLC) or optical fiber.

[0060] The power converter 20 and the subarray data acquisition unit 31 use power line carrier communication or optical fiber for communication, which improves the transmission speed of fault recording data and helps to improve the ability and efficiency of power grid fault analysis reports.

[0061] In one embodiment, the waveform data also includes a first moment when the power converter 20 starts recording and a second moment when the power grid 50 fails. When the waveform data uploaded by multiple power converters 20 in the subarray includes different first moments or different second moments, the subarray data acquisition unit 31 is used to unify the first moment and the second moment, so that the waveform data uploaded by the subarray data acquisition unit 31 to the station controller 41 by the multiple power converters 20 include the same first moment and the same second moment.

[0062] Multiple power converters 20 record waveform data according to their respective system times. The output voltage and current information in the waveform data includes corresponding time information. The waveform data also includes the first moment when the power converter 20 begins recording and the second moment when it ends recording. After collecting the waveform data from multiple power converters 20 within the subarray, the subarray data acquisition unit 31 needs to perform time synchronization. Waveform data time synchronization ensures that the event data recorded by multiple power converters 20 maintains consistency in time. When multiple power converters 20 simultaneously record event fault data, ensuring the time consistency of this data helps in better data comparison and analysis, improving data consistency and comparability.

[0063] In one embodiment, the subarray data acquisition unit 31 is further configured to generate a subarray analysis report. The subarray analysis report is used to characterize the waveform data uploaded by multiple power converters 20 within the subarray where the subarray data acquisition unit 31 is located. The subarray analysis report includes fault types, which are used to indicate at least one of the following: single-phase short circuit, two-phase short circuit, three-phase short circuit, high-voltage operation, phase loss operation, or grid tripping in the power grid 50.

[0064] After collecting waveform data uploaded by multiple power converters 20, the subarray data acquisition unit 31 automatically generates a subarray analysis report based on the waveform data of the multiple power converters 20 within the subarray. The subarray data acquisition unit 31 uses a preset algorithm or model to determine the type of fault in the power grid based on the waveform and characteristics of the fault waveform data recorded by different power converters 20. The subarray analysis report displays the analysis results of the waveform data within the subarray.

[0065] According to the scheme of this application, the subarray data acquisition unit 31 has the ability to automatically generate power grid fault analysis reports. After quickly analyzing the fault recording data, the analysis results are presented intuitively in the form of a report, which helps to improve the ability of power grid fault analysis reports, quickly locate faults, analyze fault types, and facilitate earlier power supply restoration.

[0066] In one embodiment, when the waveform data uploaded by the power converter 20 in the subarray where the subarray data acquisition unit 31 is located exceeds the first preset ratio, indicating that the three-phase voltage of the power grid 50 is asymmetrically dropped, and the positive sequence voltage of the power grid is lower than 0.9 per unit and not lower than 0.5 per unit during the three-phase voltage drop, the fault type indicates that a single-phase short circuit has occurred in the power grid 50, and the first preset ratio is greater than or equal to 80% and less than or equal to 100%.

[0067] When the waveform data uploaded by power converters 20 within the subarray containing data acquisition unit 31, exceeding the first preset ratio, all indicate an asymmetrical voltage drop in the three-phase power grid, and during the three-phase voltage drop period, the positive-sequence voltage of the power grid is lower than the low-voltage fault determination threshold but not lower than the single-phase voltage drop determination threshold, the fault type indicates a single-phase short circuit in the power grid. The low-voltage fault determination threshold can be 0.9 per unit, and the single-phase voltage drop determination threshold can be 0.5 per unit.

[0068] For example, if more than 90% of the power converters 20 in the subarray where the subarray data acquisition unit 31 is located record a three-phase voltage asymmetry drop in the power grid, and the positive sequence voltage of the power grid 50 is lower than 0.9 per unit and not lower than 0.5 per unit during the three-phase voltage asymmetry drop, then the fault type indicates that a single-phase short circuit fault has occurred in the power grid 50.

[0069] In one embodiment, when the waveform data uploaded by the power converter 20 in the subarray where the subarray data acquisition unit 31 is located exceeds the first preset ratio, indicating that the three-phase voltage of the power grid 50 is asymmetrically dropped, and the positive sequence voltage of the power grid 50 is lower than 0.4 per unit during the three-phase voltage drop, the fault type indicates that the power grid 50 has a two-phase short circuit, and the first preset ratio is greater than or equal to 80% and less than or equal to 100%.

[0070] When the waveform data uploaded by power converters 20 within the subarray containing data acquisition unit 31, exceeding the first preset ratio, all indicate a three-phase voltage asymmetry drop, and the positive sequence voltage is lower than the two-phase drop judgment threshold during the three-phase voltage drop period, the fault type indicates a two-phase short circuit in the power grid. The two-phase drop judgment threshold can be 0.4 per unit.

[0071] For example, if more than 90% of the power converters 20 in the subarray where the subarray data acquisition unit 31 is located record a three-phase voltage asymmetry drop in the power grid, and the positive sequence voltage of the power grid is lower than 0.4 per unit during the three-phase voltage asymmetry drop, then the fault type indicates that a two-phase short circuit fault has occurred in the power grid.

[0072] In one embodiment, when the waveform data uploaded by the power converter 20 in the subarray where the subarray data acquisition unit 31 is located exceeds the first preset ratio, indicating that the three-phase voltage of the power grid 50 has symmetrically dropped, and the positive sequence voltage of the power grid 50 is lower than 0.9 per unit during the three-phase voltage drop, the fault type indicates that the power grid 50 has a three-phase short circuit, and the first preset ratio is greater than or equal to 80% and less than or equal to 100%.

[0073] When the waveform data uploaded by power converters 20 within the subarray containing data acquisition unit 31, exceeding the first preset ratio, all indicate a symmetrical three-phase voltage drop, and the positive sequence voltage is lower than the low-voltage fault determination threshold during the three-phase voltage drop period, the fault type indicates a three-phase short circuit in the power grid. The low-voltage fault determination threshold can be 0.9 per unit.

[0074] For example, if more than 90% of the power converters 20 in the subarray where the subarray data acquisition unit 31 is located record a symmetrical drop in the three-phase voltage of the power grid, and the positive sequence voltage of the power grid is lower than 0.9 per unit during the symmetrical drop in the three-phase voltage of the power grid, then the fault type indicates that a three-phase short circuit fault has occurred in the power grid.

[0075] In one embodiment, when the waveform data uploaded by the power converter 20 in the subarray where the subarray data acquisition unit 31 is located exceeds the first preset ratio, indicating that the three-phase voltage of the power grid 50 is symmetrically increased, and the positive sequence voltage of the power grid 50 is higher than 1.1 per unit during the period of symmetrical increase of the three-phase voltage of the power grid 50, the fault type indicates that the power grid 50 is operating at high voltage, and the first preset ratio is greater than or equal to 80% and less than or equal to 100%.

[0076] When the waveform data uploaded by power converters 20 within the subarray containing data acquisition unit 31, exceeding the first preset ratio, all indicate a symmetrical increase in the three-phase voltage of the power grid, and the positive sequence voltage is higher than the high-voltage fault determination threshold during the period of the three-phase voltage increase, the fault type indicates that the power grid is operating at high voltage. The high-voltage fault determination threshold can be 1.1 per unit.

[0077] For example, if more than 90% of the power converters 20 in the subarray where the subarray data acquisition unit 31 is located record a symmetrical increase in the three-phase voltage of the power grid 50, and the positive sequence low voltage is higher than 1.1 per unit during the symmetrical increase in the three-phase voltage of the power grid 50, then the fault type indicates that a high voltage operation fault has occurred in the power grid 50.

[0078] In one embodiment, when the waveform data uploaded by the power converter 20 in the subarray where the subarray data acquisition unit 31 is located exceeds the first preset ratio, indicating an asymmetrical change in the three-phase voltage of the power grid 50, and the positive sequence voltage of the power grid 50 is lower than 1.1 per unit during the asymmetrical change in the three-phase voltage of the power grid 50, the fault type indicates that the power grid 50 is operating at high voltage, and the first preset ratio is greater than or equal to 80% and less than or equal to 100%.

[0079] The asymmetrical change of three-phase voltage in power grid 50 refers to the situation where the voltage of two phases increases while the voltage of the other phase decreases; or the voltage of two phases decreases while the voltage of the other phase increases.

[0080] When the waveform data uploaded by power converters 20 within the subarray containing data acquisition unit 31, exceeding the first preset ratio, all indicate asymmetrical changes in the three-phase voltage of the power grid, and the positive sequence voltage is lower than the high-voltage fault determination threshold during the asymmetrical changes in the three-phase voltage, the fault type indicates that the power grid is operating with a single phase loss. The high-voltage fault determination threshold can be 1.1 per unit.

[0081] For example, if more than 90% of the power converters 20 in the subarray where the subarray data acquisition unit 31 is located record the asymmetrical change of the three-phase voltage in the three-phase voltage of the power grid, and the positive sequence low voltage is lower than 1.1 per unit during the asymmetrical change of the three-phase voltage, then the fault type indicates that a phase loss operation fault has occurred in the power grid.

[0082] In one embodiment, the waveform data uploaded by the power converter 20 in the subarray where the subarray data acquisition unit 31 is located, which is greater than the first preset ratio, indicates that the three-phase voltage of the power grid 50 is lower than 0.05 per unit and lasts for more than 30 seconds. The fault type indicates that the power grid 50 has tripped. The first preset ratio is greater than or equal to 80% and less than or equal to 100%.

[0083] When the waveform data uploaded by power converters 20 within the subarray containing data acquisition unit 31, exceeding the first preset ratio, all indicate that the three-phase voltage of the power grid is lower than the power grid tripping threshold and the duration exceeds the duration threshold, the fault type indicates that a power grid trip has occurred. The power grid tripping threshold can be 0.05 per unit. The duration threshold can be 30 seconds.

[0084] For example, if more than 90% of the power converters 20 in the subarray where the subarray data acquisition unit 31 is located record that the three-phase voltage of the power grid is lower than 0.05 per unit for more than 30 seconds, then the fault type indicates that a power grid tripping fault has occurred in the power grid.

[0085] See also Figure 2 and Figure 3 The station controller 41 is used to collect and store waveform data uploaded by multiple subarray data acquisition units 31 when a fault occurs in the power grid 50.

[0086] The station controller 41 performs comprehensive control and management of the power converters 20 in each subarray of the power supply system 100. When a fault occurs in the power grid 50, the station controller 41 collects and stores the waveform data uploaded by multiple subarray data acquisition units 31. The station controller 41 obtains the waveform data recorded by all power converters 20 in the power supply system 100, realizes station-level fault waveform file storage, and can directly view and analyze it.

[0087] In the prior art, the power converter 20 records its internal output voltage and output current. However, since the power converters 20 are distributed, it is difficult to compare the fault response of different devices based on the fault waveform data recorded by a single power converter 20. Therefore, in this application, the power converter 20 reports fault waveform data level by level, and all fault waveform data is collected at the station controller 41. This fully utilizes the architecture of the string power supply system 100, eliminating the need for additional waveform recording equipment, and realizing overall fault waveform storage and analysis at the station level. The output voltage and output current of each power converter 20 are obtained at the station controller 41, and the fault response of different devices can be compared.

[0088] Currently, maintenance personnel use digital acquisition devices to read fault recording files one by one from the fault recording devices of power converters 20, and then analyze all the recording files to accurately locate the fault point based on the fault recording data, eliminate grid faults, and restore system operation as soon as possible. However, with the increase in the scale of the power supply system 100 and the power grid 50, the probability of accidents caused by local grid faults and the probability of the affected area expanding have also greatly increased. At the same time, the increasing number of devices in the power supply system 100 has also greatly increased the amount of information generated by the power grid 50 when a fault occurs, which objectively increases the time required for maintenance personnel to collect fault recording data, handle faults, and restore power supply. Therefore, it is possible to obtain fault recording data of all power converters 20 through the station controller 41, effectively reducing the time for manual inspection and log export and professional technicians to analyze grid events. At the same time, storing all fault recording data uniformly reduces the local storage space of the power converters 20, saving manpower and resources. It also facilitates the rapid location of the cause of grid events and improves the efficiency of fault recording analysis.

[0089] In one embodiment, the station controller 41 is also used to generate a station-level analysis report, which characterizes the waveform data uploaded by multiple subarray data acquisition units 31. The station-level analysis report includes location information, which indicates whether the fault occurs within or outside the power supply system 100.

[0090] In one embodiment, the station-level analysis report also includes a fault type, which indicates that the power grid 50 has experienced at least one of a single-phase short circuit, a two-phase short circuit, a three-phase short circuit, high-voltage operation, phase loss operation, or power grid tripping.

[0091] After collecting waveform data uploaded by multiple subarray data acquisition units 31, the station controller 41 automatically generates a station-level analysis report based on the fault waveform data. The station controller 41 uses a preset algorithm or model to determine the location of the fault based on the differences in fault waveform data recorded by different subarrays, and judges the type of fault based on the waveform and characteristics of the fault waveform data. The station-level analysis report displays the analysis results of the waveform data within the power station.

[0092] According to the solution in this application, the station controller 41 has the ability to automatically generate power grid fault analysis reports. After quickly analyzing the fault recording data, the analysis results are presented intuitively in the form of a report, which helps to improve the ability of power grid fault analysis reports, quickly locate faults, analyze fault types, and facilitate the restoration of power supply earlier.

[0093] In one embodiment, when the waveform data uploaded by the subarray data acquisition unit 31 indicates that the subarray data acquisition unit 31 has recorded at least one of the following in the power grid: single-phase short circuit, two-phase short circuit, three-phase short circuit, high voltage operation, phase loss operation, or power grid tripping, and the subarray data acquisition unit 31 has not recorded any power grid tripping fault, the location information indicates that the fault occurred outside the power supply system 100, and the second preset ratio is greater than or equal to 80% and less than or equal to 100%.

[0094] In one embodiment, when the waveform data uploaded by the subarray data acquisition unit 31 indicates that the subarray data acquisition unit 31 has recorded at least one of the following in the power grid 50: single-phase short circuit, two-phase short circuit, three-phase short circuit, high voltage operation, or phase loss operation, which is greater than the second preset ratio, and after the fault ends, the subarray data acquisition unit 31 records a tripping fault in the power grid 50 with a ratio less than the third preset ratio, the location information indicates that the fault occurred within the power supply system 100, the second preset ratio is greater than or equal to 80% and less than or equal to 100%, and the third preset ratio is greater than or equal to 40% and less than or equal to 60%.

[0095] When a fault occurs at different locations in the power grid 50, the three-phase voltage recorded by the power converter 20 in the subarray where the subarray data acquisition unit 31 is located will have different characteristics. Based on the different fault waveform data uploaded by different subarrays, the location of the fault can be located.

[0096] For example, the second preset ratio is set to 90%, and the third preset ratio is set to 50%.

[0097] In one embodiment, among the waveform data uploaded by all subarray data acquisition units 31 collected by the station controller 41, more than 90% of the subarray data acquisition units 31 recorded a single-phase short-circuit fault in the power grid 50, and no subarray data acquisition unit 31 recorded a tripping of the power grid 50. At this time, the location information indicates that the single-phase short-circuit fault occurred outside the power supply system 100.

[0098] In one embodiment, among the waveform data uploaded by all subarray data acquisition units 31 collected by the station controller 41, more than 90% of the subarray data acquisition units 31 recorded a single-phase short-circuit fault in the power grid 50, and after the single-phase short-circuit fault ended, less than 50% of the subarray data acquisition units 31 recorded that the power grid 50 tripped. At this time, the location information indicates that the single-phase short-circuit fault occurred within the power supply system 100, specifically at the subarray tie line where the subarray data acquisition unit 31 that recorded the tripping of the power grid 50 is located.

[0099] In one embodiment, among the waveform data uploaded by all subarray data acquisition units 31 collected by the station controller 41, more than 90% of the subarray data acquisition units 31 recorded a two-phase short-circuit fault in the power grid 50, and no subarray data acquisition unit 31 recorded a tripping of the power grid 50. At this time, the location information indicates that the two-phase short-circuit fault occurred outside the power supply system 100.

[0100] In one embodiment, among the waveform data uploaded by all subarray data acquisition units 31 collected by the station controller 41, more than 90% of the subarray data acquisition units 31 recorded a two-phase short-circuit fault in the power grid 50, and after the two-phase short-circuit fault ended, less than 50% of the subarray data acquisition units 31 recorded a tripping of the power grid 50. At this time, the location information indicates that the two-phase short-circuit fault occurred within the power supply system 100, specifically at the subarray tie line where the subarray data acquisition unit 31 that recorded the tripping of the power grid 50 is located.

[0101] In one embodiment, among the waveform data uploaded by all subarray data acquisition units 31 collected by the station controller 41, more than 90% of the subarray data acquisition units 31 recorded a three-phase short-circuit fault in the power grid 50, and no subarray data acquisition unit 31 recorded a tripping of the power grid 50. At this time, the location information indicates that the three-phase short-circuit fault occurred outside the power supply system 100.

[0102] In one embodiment, among the waveform data uploaded by all subarray data acquisition units 31 collected by the station controller 41, more than 90% of the subarray data acquisition units 31 recorded a three-phase short-circuit fault in the power grid 50, and after the three-phase short-circuit fault ended, less than 50% of the subarray data acquisition units 31 recorded a tripping of the power grid 50. At this time, the location information indicates that the three-phase short-circuit fault occurred within the power supply system 100, specifically at the subarray tie line where the subarray data acquisition unit 31 that recorded the tripping of the power grid 50 is located.

[0103] In one embodiment, among the waveform data uploaded by all subarray data acquisition units 31 collected by the station controller 41, more than 90% of the subarray data acquisition units 31 recorded high-voltage operation of the power grid 50, and no subarray data acquisition unit 31 recorded a tripping of the power grid 50. At this time, the location information indicates that the high-voltage operation fault occurred outside the power supply system 100.

[0104] In one embodiment, among the waveform data uploaded by all subarray data acquisition units 31 collected by the station controller 41, more than 90% of the subarray data acquisition units 31 recorded high-voltage operation of the power grid 50, and after the high-voltage operation fault ended, less than 50% of the subarray data acquisition units 31 recorded that the power grid 50 tripped. At this time, the location information indicates that the high-voltage operation fault occurred within the power supply system 100, specifically at the subarray tie line where the subarray data acquisition unit 31 that recorded the power grid 50 tripping was located.

[0105] In one embodiment, among the waveform data uploaded by all subarray data acquisition units 31 collected by the station controller 41, more than 90% of the subarray data acquisition units 31 recorded that the power grid 50 was operating with a phase loss, and no subarray data acquisition unit 31 recorded that the power grid 50 tripped. At this time, the location information indicates that the phase loss operation fault occurred outside the power supply system 100.

[0106] In one embodiment, among the waveform data uploaded by all subarray data acquisition units 31 collected by the station controller 41, more than 90% of the subarray data acquisition units 31 record that the power grid 50 is operating with a single phase loss. Furthermore, after the single-phase operation fault ends, at least one but less than 50% of the subarray data acquisition units 31 record that the power grid 50 has tripped. At this time, the location information indicates that the single-phase operation fault occurred within the power supply system 100, specifically at the subarray tie line where the subarray data acquisition unit 31 that recorded the power grid 50 tripping is located.

[0107] In one embodiment, among the waveform data uploaded by all subarray data acquisition units 31 collected by the station controller 41, more than 90% of the subarray data acquisition units 31 recorded a tripping of the power grid 50. At this time, the location information indicates that the tripping fault of the power grid 50 occurred outside the power supply system 100.

[0108] According to the scheme in this application, the location information of the fault can be determined based on the fault characteristics recorded in the fault waveform data in different subarrays. This is beneficial to improving the fault analysis and reporting capabilities of the power grid, quickly analyzing the fault type, and facilitating earlier power restoration.

[0109] See also Figure 2 and Figure 3In one embodiment, the power supply system 100 further includes a data conversion unit 32, which is used to convert the original format waveform data into a target format, the original format including text format and the target format including COMTRADE.

[0110] When recording fault waveform data, the power converter 20 records the data in its raw format, generating a string of text data, such as in Excel format. However, the raw format data is not conducive to data analysis. Therefore, a data conversion unit 32 is set up to convert the raw format data so that the fault waveform file meets the industry's common analysis format, such as COMTRADE format. COMTRADE is a standard common format for power system transient data exchange from the Institute of Electrical and Electronics Engineers (IEEE). It has been widely used in the dynamic recording and fault recording of power systems. As a standard format, it defines a file format for containing transient waveforms and event data obtained from power systems or power system models. By analyzing the relevant file data recorded in COMTRADE format files, the causes and types of faults occurring in the power system can be analyzed and determined, and a common format data basis can be provided for accident analysis.

[0111] It should be understood that the data conversion unit 32 is located in each power converter 20, or in the subarray data acquisition unit 31, or in the station controller 41.

[0112] Preferably, the data conversion unit 32 is located in the subarray data acquisition unit 31 of the box-type substation 30.

[0113] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A power supply system, characterized in that, The power supply system includes a station controller and multiple subarrays, each subarray including multiple power converters and a subarray data acquisition unit; The power converter is used to convert DC power from photovoltaic modules or energy storage devices into AC power and input it into the power grid. The power converter includes an output terminal and a communication interface. The power converter is also used to upload waveform data when the power grid fails to the subarray data acquisition unit of the subarray where the power converter is located through the communication interface. The waveform data includes the voltage and output current information output by the output terminal of the power converter. The subarray data acquisition unit is used to collect and upload waveform data uploaded by multiple power converters within the subarray where the subarray data acquisition unit is located when the power grid fails. The station controller is used to collect and store waveform data uploaded by multiple subarray data acquisition units when the power grid fails.

2. The power supply system according to claim 1, characterized in that, The recorded waveform data also includes the first moment when the power converter starts recording and the second moment when recording ends when the power grid fault occurs. When the waveform data uploaded by multiple power converters in the subarray includes different first times or different second times, the subarray data acquisition unit is used to unify the first time and the second time, so that the waveform data uploaded by the subarray data acquisition unit to the station controller of multiple power converters includes the same first time and the same second time.

3. The power supply system according to claim 1 or 2, characterized in that, The subarray data acquisition unit is also used to generate a subarray analysis report. The subarray analysis report is used to characterize the waveform data uploaded by multiple power converters in the subarray where the subarray data acquisition unit is located. The subarray analysis report includes fault types, which are used to indicate that the power grid has experienced at least one of the following: single-phase short circuit, two-phase short circuit, three-phase short circuit, high-voltage operation, phase loss operation, or power grid tripping.

4. The power supply system according to any one of claims 1-3, characterized in that, The station controller is also used to generate a station-level analysis report, which is used to characterize the waveform data uploaded by multiple subarray data acquisition units. The station-level analysis report includes location information, which is used to indicate whether the fault occurs within or outside the power supply system.

5. The power supply system according to claim 4, characterized in that, The station-level analysis report also includes fault types, which indicate at least one of the following: single-phase short circuit, two-phase short circuit, three-phase short circuit, high-voltage operation, phase loss operation, or grid tripping.

6. The power supply system according to any one of claims 3-5, characterized in that, When the waveform data uploaded by the power converter in the subarray where the subarray data acquisition unit is located exceeds the first preset ratio indicates that the three-phase voltage of the power grid is asymmetrically dropped, and the positive sequence voltage of the power grid is lower than 0.9 per unit and not lower than 0.5 per unit during the three-phase voltage drop, the fault type indicates that a single-phase short circuit has occurred in the power grid, and the first preset ratio is greater than or equal to 80% and less than or equal to 100%.

7. The power supply system according to any one of claims 3-5, characterized in that, When the waveform data uploaded by the power converter in the subarray where the subarray data acquisition unit is located exceeds the first preset ratio indicates that the three-phase voltage of the power grid is asymmetrically dropped, and the positive sequence voltage of the power grid is lower than 0.4 per unit during the three-phase voltage drop, the fault type indicates that the power grid has a two-phase short circuit, and the first preset ratio is greater than or equal to 80% and less than or equal to 100%.

8. The power supply system according to any one of claims 3-5, characterized in that, When the waveform data uploaded by the power converter in the subarray where the subarray data acquisition unit is located exceeds the first preset ratio indicates that the three-phase voltage of the power grid has symmetrically dropped, and the positive sequence voltage of the power grid is lower than 0.9 per unit during the three-phase voltage drop, the fault type indicates that the power grid has a three-phase short circuit, and the first preset ratio is greater than or equal to 80% and less than or equal to 100%.

9. The power supply system according to any one of claims 4-8, characterized in that, When the waveform data uploaded by the subarray data acquisition unit indicates that the subarray data acquisition unit has recorded at least one of the following faults in the power grid: single-phase short circuit, two-phase short circuit, three-phase short circuit, high voltage operation, phase loss operation, or power grid tripping, and the subarray data acquisition unit has not recorded any power grid tripping fault, the location information indicates that the fault occurred outside the power supply system, and the second preset ratio is greater than or equal to 80% and less than or equal to 100%.

10. The power supply system according to any one of claims 4-8, characterized in that, When the waveform data uploaded by the subarray data acquisition unit indicates that at least one of the following occurs in the power grid: single-phase short circuit, two-phase short circuit, three-phase short circuit, high-voltage operation, or phase loss operation, and after the fault ends, less than a third preset proportion of subarray data acquisition units record a power grid tripping fault, the location information indicates that the fault occurred within the power supply system. The second preset proportion is greater than or equal to 80% and less than or equal to 100%, and the third preset proportion is greater than or equal to 40% and less than or equal to 60%.

11. A power converter applied in a power supply system, characterized in that, The power supply system includes a station controller and multiple subarrays, each subarray including a power converter and a subarray data acquisition unit; The power converter is used to convert DC power from photovoltaic modules or energy storage devices into AC power and input it into the power grid. The power converter includes an output terminal and a communication interface. The power converter is also used to upload waveform data when the power grid fails to the subarray data acquisition unit of the subarray where the power converter is located through the communication interface. The waveform data includes the voltage and output current information output by the output terminal of the power converter. The power converter is used to upload the waveform data recorded when the power grid fails to the subarray data acquisition unit, so that the waveform data recorded when the power grid fails can be further uploaded to the station controller through the subarray data acquisition unit.

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