A method and device for detecting arc fault on the DC side of a photovoltaic inverter

Abstract

The application discloses a kind of photovoltaic inverter DC side arc fault detection method and detection device, method includes: the operating parameter of photovoltaic inverter under different working conditions is collected, whether the arc fault is generated according to operating parameter and the fault arc type when arc fault is generated;According to the fault arc type judged to the corresponding control instruction of photovoltaic inverter is issued, to further locate the MPPT of the road of arc fault and carry out protection;The MPPT of the road of arc fault positioned is detected twice to ensure the accuracy of detection;According to the MPPT of the road of arc fault positioned and the temperature sensor further determined on the photovoltaic panel arc fault specific position, to carry out operation and maintenance investigation repair.The application can realize the accurate detection and quick breaking protection of photovoltaic DC side arc fault, reduce system cost.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic inverter testing and protection technology, specifically to a method and device for detecting arcing faults on the DC side of a photovoltaic inverter. Background Technology

[0002] With the rapid development of the photovoltaic industry, high-power photovoltaic modules (182 / 210) and 1500V DC systems have become the market mainstream. The DC-side power and current of photovoltaic systems are constantly increasing, and the DC system voltage is constantly rising (it will develop towards 2000V in the future). However, while the continuous increase in module current and DC-side voltage reduces the levelized cost of electricity (LCOE), it also brings higher safety risks due to DC-side faults.

[0003] In photovoltaic (PV) systems, the numerous DC-side terminals—with megawatt-scale PV power plants containing tens of thousands of contact points—make the possibility of arcing hazards extremely high when loose connections occur. Arcing refers to the state where voltage breakdown of the air in PV-related equipment creates an electric arc. If accurate fault detection and rapid shutdown are not achieved, the continuously burning arc can ignite an electrical fire, causing significant property damage and even threatening personal safety. Therefore, detecting and protecting against DC arcing is a crucial issue in addressing DC arcing in PV inverters. Currently, mainstream arcing detection in the photovoltaic industry is designed around standards UL1699B and GB / T39750-2021. These standards only cover series arcing detection solutions, lacking clear guidelines for parallel and grounded arcing detection strategies. However, parallel and grounded arcing cause equally serious damage, requiring different solutions, necessitating classification and identification. To control the independent disconnection of the arcing circuit MPPT without affecting other normal power generation, it's necessary to consider crosstalk between adjacent lines when the received sensor signal is transmitted on the PCB board, affecting the independent disconnection of the arcing circuit MPPT. Therefore, crosstalk reduction or control logic modification is required within a certain space. Simultaneously, if the arcing location is on the photovoltaic panel, the specific location of the arcing fault needs to be quickly and accurately determined to improve maintenance efficiency. Finally, to reduce the impact of false detections on power generation while ensuring no missed detections, secondary re-inspection is required. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and device for detecting arcing faults on the DC side of a photovoltaic inverter, thereby achieving accurate detection and rapid disconnection protection of arcing faults on the DC side of the photovoltaic inverter and reducing system costs.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for detecting arcing faults on the DC side of a photovoltaic inverter includes the following steps: S1 collects the operating parameters of the photovoltaic inverter under different operating conditions, and determines whether an arcing fault occurs and the type of arcing fault when it occurs based on the operating parameters. S2, based on the determined arcing fault type, sends corresponding control commands to the photovoltaic inverter to further locate the MPPT of the arcing fault circuit and perform protection. S3, perform a second inspection on the MPPT of the path where the arcing fault has been located to ensure the accuracy of the inspection; S4. Based on the MPPT of the circuit where the arcing fault is located and the temperature sensor installed on the photovoltaic panel, the specific location of the arcing fault is further determined for operation and maintenance troubleshooting and repair.

[0006] Further, step S1 includes: Collect voltage, current, and power operating parameters of the photovoltaic inverter under shutdown, startup, power generation, and full-load power generation conditions; The current characteristic threshold of the collected current signal is used to determine whether an arcing fault has occurred. If the current characteristic value of half of the sampling points is greater than the current characteristic threshold within a judgment period, an arcing fault is determined to have occurred. At this time, it is further determined whether the voltage of MPPT has changed. If the voltage has not changed, the arcing fault type is determined to be series arcing. If the voltage has changed, it is further determined whether the MPPT voltage is the voltage to ground or whether the insulation monitoring grounding is reported at the same time. If so, the arcing fault type is determined to be grounding arcing. Otherwise, the judgment is continued based on the magnitude of the MPPT voltage change. If the voltage drop exceeds the preset voltage value, the arcing fault type is determined to be parallel arcing of some photovoltaic modules. If the voltage drop is 0, the arcing fault type is determined to be parallel arcing of the entire string of modules.

[0007] Further, step S2 includes: If the arcing fault is determined to be a series arcing fault, a control command is issued to put the photovoltaic inverter into standby mode and check whether the standby voltage of each MPPT is 0. If the standby voltage of one MPPT is found to be 0, the control shuts down that MPPT, and the other MPPTs start generating electricity normally. If the standby voltage of each MPPT is not 0, the system starts screening from the first MPPT and sends pulse signals to the other MPPTs except the screened MPPT until no arcing detection is reported. At this time, this MPPT is the arcing fault MPPT, and the control shuts down this MPPT, and the other MPPTs start generating electricity normally. If the fault arcing type is determined to be parallel arcing, a control command is issued to shut down the MPPT on the abnormal voltage path, while the other MPPTs start generating electricity normally. If the fault arcing type is determined to be ground arcing, a control command is issued to shut down the MPPT that reports the grounding of the MPPT voltage to ground voltage. Other MPPTs will start generating electricity normally.

[0008] Further, step S3 includes: Only close the MPPT of the circuit where the arcing fault has been located and close the other MPPTs. If there is no arcing fault at this time, it indicates a false detection, and the false detection result is recorded. If there is an arcing fault at this time, disconnect the MPPT of the circuit where the arcing fault has been located and record that the MPPT of that circuit needs to be manually reset. Finally, issue a control command to close the other MPPTs and start the generator normally.

[0009] Furthermore, in step S4, the specific arrangement of the temperature sensors deployed on the photovoltaic panel is as follows: A temperature sensor is installed at each of the four corners and the center of the photovoltaic panel; To pinpoint the exact location of an arcing fault, based on the inverse relationship between the intensity of the temperature jump at the arcing point and the distance to the arcing source, five temperature sensors were used to locate the specific arcing position. The specific steps are as follows: Calculate the total temperature rise of the four sensors located at the four corners of the photovoltaic panel; The coordinate coefficients of the specific arcing location on the X and Y axes are calculated based on the total temperature rise. The calculation expression is as follows:

[0010]

[0011] Tt= Ta+ Tb+ Tc+ Td In the above formula, Ta、 Tb, Tc, Td represents the temperature rise of four sensors located at the four corners of the photovoltaic panel. Tt represents the total temperature rise; coordinate coefficients Mapping to actual coordinates yields the actual coordinates of the specific arc position. and The calculation expression is:

[0012]

[0013] In the above formula, These are the height and width of the photovoltaic panel, respectively.

[0014] Temperature rise of intermediate temperature sensor T eFor auxiliary reference. If T e - T t When the value is greater than 0, it indicates that the heat source is in the central area of ​​the photovoltaic panel.

[0015] A photovoltaic inverter DC-side arcing fault detection device includes: The arcing detection module is used to collect the operating parameters of the photovoltaic inverter under different operating conditions, and to determine whether an arcing fault has occurred and the type of arcing fault when it occurs based on the operating parameters. The arcing fault location module is used to send corresponding control commands to the photovoltaic inverter according to the determined arcing fault type, so as to further locate the MPPT of the circuit where the arcing fault is located and perform protection. The arc fault re-inspection module is used to perform secondary inspections on the MPPT of the path where the arc fault has been located to ensure the accuracy of the inspection. The photovoltaic module fault location module is used to further determine the specific location of the arcing fault based on the MPPT of the circuit where the arcing fault is located and the temperature sensors deployed on the photovoltaic panel, so as to carry out operation and maintenance troubleshooting and repair.

[0016] Furthermore, the photovoltaic inverter DC-side arcing fault detection device also includes a communication module and a control module. The communication module is connected to the control module, the photovoltaic module fault location module, the arcing detection module, and the arcing fault re-inspection module. The communication module is used for transmitting communication signals within the photovoltaic inverter DC-side arcing fault detection device. The control module is connected to the MPPT on / off control module and the inverter on / off control module and is used to control the switching action of the inverter.

[0017] Furthermore, the photovoltaic inverter DC-side arcing fault detection device also includes a filtering module, which is used to filter out noise in the collected current signal to reduce interference.

[0018] A DC-side arcing fault detection system for a photovoltaic inverter includes a microprocessor and a memory interconnected, wherein the microprocessor is programmed or configured to execute the steps of a DC-side arcing fault detection method for a photovoltaic inverter.

[0019] A computer-readable storage medium storing a computer program / instructions programmed or configured to execute, via a processor, the steps of a method for detecting arcing faults on the DC side of a photovoltaic inverter.

[0020] Compared with the prior art, the advantages of the present invention are as follows: This invention achieves accurate identification and protection against arcing faults in photovoltaic systems through a multi-stage detection and fault location process: by monitoring operating parameters, the type of arcing can be quickly and accurately identified, enabling early warning; by issuing control commands to locate the MPPT channel where the fault is located and implement protection, the spread of the fault and equipment damage can be prevented; secondary detection improves the accuracy of judgment and reduces false alarms and missed detections; by combining with a temperature sensor, the arcing location can be accurately located, facilitating efficient troubleshooting and repair by operation and maintenance personnel, thereby improving the safety and reliability of the photovoltaic system. Attached Figure Description

[0021] Figure 1 This is a flowchart of a photovoltaic inverter DC-side arcing fault detection method according to an embodiment of the present invention.

[0022] Figure 2 This is a flowchart illustrating the arc fault classification in an embodiment of the present invention.

[0023] Figure 3 This is a flowchart of MPPT detection and protection for the circuit where the arcing fault is located in an embodiment of the present invention.

[0024] Figure 4 This is a flowchart illustrating the secondary detection of MPPT on the path where the arcing fault has been located, as described in this embodiment of the invention.

[0025] Figure 5 This is a schematic diagram showing the arrangement of the temperature sensor on the photovoltaic panel in a specific application embodiment.

[0026] Figure 6 This is a flowchart illustrating the arc positioning process of a photovoltaic panel in an embodiment of the present invention.

[0027] Figure 7 This is a schematic diagram of a photovoltaic inverter DC-side arcing fault detection device according to an embodiment of the present invention.

[0028] Figure 8 This is a schematic diagram of a DC-side arcing fault detection circuit for a photovoltaic inverter, as shown in a specific application embodiment. Detailed Implementation

[0029] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0030] The following is a description of some of the terms used in this invention: PV: photovoltaic, solar power generation; MPPT: Maximum Power Point Tracking.

[0031] Example 1 like Figure 1 As shown, the method for detecting arcing faults on the DC side of a photovoltaic inverter in this embodiment includes the following steps: S1 collects the operating parameters of the photovoltaic inverter under different operating conditions, and determines whether an arcing fault occurs and the type of arcing fault when it occurs based on the operating parameters. S2, based on the determined arcing fault type, sends corresponding control commands to the photovoltaic inverter to further locate the MPPT of the arcing fault circuit and perform protection. S3, perform a second inspection on the MPPT of the path where the arcing fault has been located to ensure the accuracy of the inspection; S4. Based on the MPPT of the circuit where the arcing fault is located and the temperature sensors deployed on the photovoltaic panel, the specific location of the arcing fault is further determined for maintenance and troubleshooting. The detection method in this embodiment can achieve accurate fault detection and rapid disconnection protection, reduce system costs, and adapt to the needs of future large-scale module development.

[0032] In this embodiment, step S1 includes: Collect voltage, current, and power operating parameters of the photovoltaic inverter under shutdown, startup, power generation, and full-load power generation conditions; The current characteristic threshold of the collected current signal is used to determine whether an arcing fault has occurred. If the current characteristic value of half of the sampling points is greater than the current characteristic threshold within a judgment period, an arcing fault is determined to have occurred. At this time, it is further determined whether the MPPT voltage has changed. If the voltage has not changed, the arcing fault type is determined to be series arcing. If the voltage has changed, it is further determined whether the MPPT voltage is the voltage to ground or whether the insulation monitoring grounding is reported at the same time. If so, the arcing fault type is determined to be grounding arcing. Otherwise, the judgment is continued based on the magnitude of the MPPT voltage change. If the voltage drop exceeds the preset voltage value, the arcing fault type is determined to be parallel arcing of some photovoltaic modules. If the voltage drop is 0, the arcing fault type is determined to be parallel arcing of the entire string of modules (partial modules and the entire string of modules refer to some modules included in one PV and all modules included in one PV, respectively).

[0033] In specific application embodiments, to address the issue of accurately identifying the type of arcing fault, since common arcing classifications include series arcing, parallel arcing, and grounding arcing, an arcing type identification device can be installed inside the inverter. Based on the voltage, current, and power relationships collected by sensors under different inverter operating conditions (shutdown, startup, power generation, full load power generation), fused parameter feature values ​​are constructed, and an arcing classification library is established according to these fused parameter feature values ​​under different operating conditions. When the sensor collects the characteristics of the corresponding arcing fault type, the information is transmitted to the control system for corresponding fault alarm and protection. Figure 2 The diagram shown is a flowchart for classifying arcing faults. The changes caused by different arcing faults are as follows: Series arcing: MPPT voltage remains unchanged; Parallel arcing: Entire string: MPPT voltage drops to 0; One or more blocks in string: MPPT voltage drops by more than 45V; Grounding: MPPT voltage to ground voltage or simultaneously report insulation monitoring grounding.

[0034] In this embodiment, step S2 includes: If the arcing fault is determined to be a series arcing fault, a control command is issued to put the photovoltaic inverter into standby mode and check whether the standby voltage of each MPPT is 0. If the standby voltage of one MPPT is found to be 0, the control shuts down that MPPT, and the other MPPTs start generating electricity normally. If the standby voltage of each MPPT is not 0, the system starts screening from the first MPPT and sends pulse signals to the other MPPTs except the screened MPPT until the system no longer reports arcing. At this time, this MPPT is the arcing fault MPPT, and the control shuts down this MPPT, and the other MPPTs start generating electricity normally. If the fault arcing type is determined to be parallel arcing, a control command is issued to shut down the MPPT on the abnormal voltage path, while the other MPPTs start generating electricity normally. If the fault arcing type is determined to be ground arcing, a control command is issued to shut down the MPPT that reports the grounding of the MPPT voltage to ground voltage. Other MPPTs will start generating electricity normally.

[0035] In specific application examples, when multiple MPPTs are generating power, the common strategy for protecting only the MPPT experiencing arcing while other fault-free MPPTs continue normal power generation is to uniformly shut down the inverter to prevent further damage from continued inverter power generation. However, if false detection occurs, the inverter's power output will be affected. Even if only one MPPT experiences arcing, the data collected by the sensors will generate crosstalk on the PCB board, affecting the data acquisition of other MPPTs. Figure 3The diagram shows the MPPT detection and protection flowchart for the arcing fault path. This embodiment designs an identification strategy to accurately control the arcing MPPT path to disconnect, while other normal parts can still generate electricity normally. The specific strategy is as follows: If a series arcing is detected, the inverter is first put into standby mode. After standby, there are two possibilities at the arcing point: 1) open circuit 2) loose connection. 1) If one path has a voltage of 0, it is the arcing MPPT path. 2) Starting from the first MPPT path, trigger pulses are sent to all MPPTs except the detected path. If no arcing detection is reported, the detected path is arcing; if a parallel arcing of photovoltaic modules is detected, the path with a voltage drop is the arcing MPPT path; if a parallel arcing of the entire string is detected, the path with a voltage drop to 0 is the arcing MPPT path; if a grounding arcing is detected, the path with abnormal ground voltage is determined to be the arcing MPPT path, consistent with the insulation detection judgment MPPT logic.

[0036] In this embodiment, step S3 includes: Only close the MPPT of the circuit where the arcing fault has been located and close the other MPPTs. If there is no arcing fault at this time, it indicates a false detection, and the false detection result is recorded. If there is an arcing fault at this time, disconnect the MPPT of the circuit where the arcing fault has been located and record that the MPPT of that circuit needs to be manually reset. Finally, issue a control command to close the other MPPTs and start the generator normally.

[0037] In a specific application embodiment, regarding the issue of how to perform secondary detection on the abnormal part after circuit breaking when judging that one (or multiple) MPPTs are arcing abnormally, thereby reducing the impact of false alarms on power generation, this is an extension based on step S2 to judge the false detection of the faulty MPPT. While minimizing the missed detection rate, the false detection rate will relatively increase. Only the MPPT that detected the arcing fault is closed, and after secondary detection, the normal MPPT operation is restored. If no arcing fault is reported, it is a false detection, and other MPPTs are closed to generate power. If an arcing fault is still detected or the MPPT cannot generate power normally, an alarm is triggered, the switch of that MPPT is disconnected, and manual reset is required. Other normal MPPTs are then closed to generate power. The specific flowchart is as follows: Figure 4 As shown.

[0038] In this embodiment, the specific arrangement of the temperature sensors deployed on the photovoltaic panel in step S4 is as follows: A temperature sensor is installed at each of the four corners and the center of the photovoltaic panel; To pinpoint the exact location of an arcing fault, based on the inverse relationship between the intensity of the temperature jump at the arcing point and the distance to the arcing source, five temperature sensors were used to locate the specific arcing position. The specific steps are as follows: Calculate the total temperature rise of the four sensors located at the four corners of the photovoltaic panel; The coordinate coefficients of the specific arcing location on the X and Y axes are calculated based on the total temperature rise. The calculation expression is as follows:

[0039]

[0040] Tt= Ta+ Tb+ Tc+ Td In the above formula, Ta、 Tb, Tc, Td represents the temperature rise of four sensors located at the four corners of the photovoltaic panel. Tt represents the total temperature rise; coordinate coefficients Mapping to actual coordinates yields the actual coordinates of the specific arc position. and The calculation expression is:

[0041]

[0042] In the above formula, These are the height and width of the photovoltaic panel, respectively.

[0043] Temperature rise of intermediate temperature sensor T e For supplementary reference, if T e - T t When the value is >0, it indicates that the heat source is in the central area of ​​the photovoltaic panel, which is beneficial for locating the arcing position of the photovoltaic panel more quickly.

[0044] It is understandable that by using the layout strategy of four corners and one center, when a heat source is on the photovoltaic panel, the sensors that are closer will rise more and the sensors that are farther away will rise less. By analyzing the relative differences in the readings of the five sensors, the specific location of the heat source on the photovoltaic panel can be deduced, thereby locating the specific location where the arcing occurs.

[0045] In a specific application embodiment, to address the problem of quickly locating the arcing fault when a cell on a photovoltaic module experiences a fault arcing, temperature sensors are installed on the back of the photovoltaic panel to form an arcing fault location identification network. When the module experiences an arcing fault, after identifying the arcing path MPPT based on the second problem, the temperature at this arcing point will experience a sudden change. The intensity of the change is inversely proportional to the distance from the arcing source. Using five temperature sensors, the specific arcing location can be located, as shown in the location diagram. Figure 5 As shown in the diagram. The data collected by the sensors is processed and analyzed by the arcing fault location module to determine the specific location of the arcing, facilitating maintenance and troubleshooting. The photovoltaic panel arcing location process is as follows: Figure 6 As shown.

[0046] Example 2 like Figure 7 As shown, the DC-side arcing fault detection device for photovoltaic inverters in this embodiment includes: The arcing detection module is used to collect the operating parameters of the photovoltaic inverter under different operating conditions, and to determine whether an arcing fault has occurred and the type of arcing fault when it occurs based on the operating parameters. The arcing fault location module is used to send corresponding control commands to the photovoltaic inverter according to the determined arcing fault type, so as to further locate the MPPT of the circuit where the arcing fault is located and perform protection. The arc fault re-inspection module is used to perform secondary inspections on the MPPT of the path where the arc fault has been located to ensure the accuracy of the inspection. The photovoltaic module fault location module is used to further determine the specific location of the arcing fault based on the MPPT of the circuit where the arcing fault is located and the temperature sensors deployed on the photovoltaic panel, so as to carry out operation and maintenance troubleshooting and repair.

[0047] In this embodiment, the photovoltaic inverter DC-side arcing fault detection device further includes a communication module and a control module. The communication module is connected to the control module, the photovoltaic module fault location module, the arcing detection module, and the arcing fault re-inspection module. The communication module is used for transmitting communication signals within the photovoltaic inverter DC-side arcing fault detection device. The control module is connected to the MPPT on / off control module and the inverter on / off control module and is used to control the switching action of the inverter.

[0048] In this embodiment, the DC-side arcing fault detection device for photovoltaic inverters further includes a filtering module for filtering out noise in the collected current signal to reduce interference.

[0049] In specific application embodiments Figure 7 and Figure 8 The detection device shown includes: Arcing detection system: A system for detecting and protecting against arcing faults on the DC side of string photovoltaic panels; Arc detection module: The core algorithm for arc detection can detect arc faults through current characteristics, including a crosstalk filtering module to minimize interference; Filtering module: Filters out noise from the acquired current signal and reduces interference; Arcing type determination module: It can determine whether the arcing is a series arcing, parallel arcing, or grounding arcing based on different voltage characteristics; Arc fault location module: works with the photovoltaic module fault location network to determine the specific arc location; Arc fault re-inspection module: Secondary check to see if false detections have occurred; Communication system: Transmission of system communication signals; Control system: controls the switching action of the inverter.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows: By identifying the type of arcing, the type of arcing that causes the fault can be accurately determined, enabling rapid and accurate identification of the type of arcing and thus quickly finding the appropriate handling method. By using the MPPT-level arcing detection and control method, when multiple MPPTs are generating electricity, only the MPPT that has an arcing fault is protected, while the other MPPTs continue to generate electricity normally without faults. This can achieve MPPT-level arcing self-disconnection protection, quickly and accurately disconnecting the MPPT that caused the arcing, without affecting the normal power generation of other MPPTs. Adding an arcing location device to photovoltaic modules can quickly and accurately locate the arcing when a cell on a photovoltaic module experiences a faulty arcing, so that maintenance can handle it quickly. By using the arcing retest control method, when an arcing anomaly is detected in one (or multiple) MPPT circuits, a secondary test can be performed on the abnormal part after the circuit is disconnected. Automatic reconnection is performed in case of false arcing diagnosis, thereby reducing the impact of false arcing on the inverter's power generation.

[0051] The present invention further provides a DC-side arcing fault detection system for a photovoltaic inverter, including a microprocessor and a memory interconnected thereto, wherein the microprocessor is programmed or configured to execute the steps of a DC-side arcing fault detection method for a photovoltaic inverter.

[0052] The present invention further provides a computer-readable storage medium storing a computer program / instructions, the computer program / instructions being programmed or configured to execute the steps of a method for detecting arcing faults on the DC side of a photovoltaic inverter via a processor.

[0053] The system and medium of the present invention, corresponding to the methods described above, also have the advantages described above.

[0054] The present invention can implement all or part of the processes in the methods of the above embodiments, or it can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, it can implement the steps of the above method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. Computer-readable media include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. The memory is used to store computer programs and / or modules. The processor implements various functions by running or executing the computer programs and / or modules stored in the memory, and by calling data stored in the memory. The memory may include high-speed random access memory, as well as non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart media cards (SMC), secure digital (SD) cards, flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0055] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for detecting arcing faults on the DC side of a photovoltaic inverter, characterized in that, Including the following steps: S1 collects the operating parameters of the photovoltaic inverter under different operating conditions, and determines whether an arcing fault occurs and the type of arcing fault when it occurs based on the operating parameters. S2, based on the determined arcing fault type, sends corresponding control commands to the photovoltaic inverter to further locate the MPPT of the arcing fault circuit and perform protection. If the arcing fault is determined to be a series arcing fault, a control command is issued to put the photovoltaic inverter into standby mode and check whether the standby voltage of each MPPT is 0. If the standby voltage of one MPPT is found to be 0, the control shuts down that MPPT, and the other MPPTs start generating electricity normally. If the standby voltage of each MPPT is not 0, the system starts screening from the first MPPT and sends pulse signals to the other MPPTs except the screened MPPT until no arcing detection alarm is issued. At this time, the screened MPPT is the arcing fault MPPT, and the control shuts down the screened MPPT, and the other MPPTs start generating electricity normally. If the fault arcing type is determined to be parallel arcing, a control command is issued to shut down the MPPT on the abnormal voltage path, while the other MPPTs start generating electricity normally. If the fault arcing type is determined to be ground arcing, then the MPPT with MPPT voltage down to ground voltage and reporting insulation monitoring grounding alarm is designated as the faulty MPPT, and a control command is issued to shut down the faulty MPPT, while the other MPPTs start generating electricity normally. S3, perform a second inspection on the MPPT of the path where the arcing fault has been located to ensure the accuracy of the inspection; S4. Based on the MPPT of the circuit where the arcing fault is located and the temperature sensor installed on the photovoltaic panel, the specific location of the arcing fault is further determined for operation and maintenance troubleshooting and repair.

2. The method for detecting arcing faults on the DC side of a photovoltaic inverter according to claim 1, characterized in that, Step S1 includes: Collect voltage, current, and power operating parameters of the photovoltaic inverter under shutdown, startup, power generation, and full-load power generation conditions; The current characteristic threshold of the collected current signal is used to determine whether an arcing fault has occurred. If the current characteristic value of half of the sampling points is greater than the current characteristic threshold within a judgment period, an arcing fault is determined to have occurred. At this time, it is further determined whether the voltage of MPPT has changed. If the voltage has not changed, the arcing fault type is determined to be series arcing. If the voltage has changed, it is further determined whether the MPPT voltage is the voltage to ground or whether the insulation monitoring grounding is reported at the same time. If so, the arcing fault type is determined to be grounding arcing. Otherwise, the judgment is continued based on the magnitude of the MPPT voltage change. If the voltage drop exceeds the preset voltage value, the arcing fault type is determined to be parallel arcing of some photovoltaic modules. If the voltage drop is 0, the arcing fault type is determined to be parallel arcing of the entire string of modules.

3. The method for detecting arcing faults on the DC side of a photovoltaic inverter according to claim 1, characterized in that, Step S3 includes: Only activate the MPPT on the path where the arcing fault has been located, and disconnect the MPPTs on other paths. If no arcing fault is detected at this time, it indicates a false detection, and the false detection result is recorded. If an arcing fault is detected at this time, disconnect the MPPT on the path where the arcing fault has been located, and record that the MPPT on that path needs to be manually reset. Finally, issue a control command to restore the normal start-up and power generation of the other MPPTs.

4. The method for detecting arcing faults on the DC side of a photovoltaic inverter according to claim 1, characterized in that, In step S4, the specific arrangement of the temperature sensors deployed on the photovoltaic panel is as follows: A temperature sensor is installed at each of the four corners and the center of the photovoltaic panel; To pinpoint the exact location of an arcing fault, based on the inverse relationship between the intensity of the temperature jump at the arcing point and the distance to the arcing source, five temperature sensors were used to locate the specific arcing location. The specific steps are as follows: Calculate the total temperature rise of the four sensors located at the four corners of the photovoltaic panel; The coordinate coefficients of the specific arcing location on the X and Y axes are calculated based on the total temperature rise. The calculation expression is as follows: In the above formula, These are the temperature rise readings of four sensors located at the four corners of the photovoltaic panel. Total temperature rise; coordinate coefficients Mapping to actual coordinates yields the actual coordinates of the specific arc position. and The calculation expression is: In the above formula, These are the height and width of the photovoltaic panel, respectively.

5. A device for detecting arcing faults on the DC side of a photovoltaic inverter, characterized in that, include: The arcing detection module is used to collect the operating parameters of the photovoltaic inverter under different operating conditions, and to determine whether an arcing fault has occurred and the type of arcing fault when it occurs based on the operating parameters. The arcing fault location module is used to issue corresponding control commands to the photovoltaic inverter based on the determined arcing fault type, in order to further locate the MPPT in the faulty circuit and perform protection. Specifically, if the arcing fault type is determined to be a series arcing, a control command is issued to put the photovoltaic inverter into standby mode, and the standby voltage of each MPPT is checked to see if it is 0. If the standby voltage of one MPPT is found to be 0, that MPPT is shut down, while the other MPPTs start generating electricity normally. If the standby voltage of all MPPTs is not 0, the module filters from the first MPPT onwards, sending commands to the remaining MPPTs. The MPPT in the selected path sends pulse signals until no arcing detection alarm is issued. At this point, the selected path is the arcing-generating MPPT, and the control shuts down the selected path MPPT, while the other MPPTs start generating power normally. If the arcing fault type is determined to be parallel arcing, a control command is issued to shut down the path MPPT with abnormal voltage, while the other MPPTs start generating power normally. If the arcing fault type is determined to be grounding arcing, the MPPT with voltage to ground and reporting an insulation monitoring grounding alarm is designated as the faulty path MPPT, and a control command is issued to shut down the faulty path MPPT, while the other MPPTs start generating power normally. The arc fault re-inspection module is used to perform secondary inspections on the MPPT of the path where the arc fault has been located to ensure the accuracy of the inspection. The photovoltaic module fault location module is used to further determine the specific location of the arcing fault based on the MPPT of the circuit where the arcing fault is located and the temperature sensors deployed on the photovoltaic panel, so as to carry out operation and maintenance troubleshooting and repair.

6. The photovoltaic inverter DC-side arcing fault detection device according to claim 5, characterized in that, The photovoltaic inverter DC-side arcing fault detection device also includes a communication module and a control module. The communication module is connected to the control module, the photovoltaic module fault location module, the arcing detection module, and the arcing fault re-inspection module. The communication module is used for the transmission of communication signals within the photovoltaic inverter DC-side arcing fault detection device. The control module is connected to the MPPT on / off control module and the inverter on / off control module and is used to control the switching action of the inverter.

7. The photovoltaic inverter DC-side arcing fault detection device according to claim 5, characterized in that, The DC-side arcing fault detection device for photovoltaic inverters also includes a filtering module, which is used to filter out noise in the collected current signal to reduce interference.

8. A DC-side arcing fault detection system for a photovoltaic inverter, comprising a microprocessor and a memory interconnected, characterized in that, The microprocessor is programmed or configured to perform the steps of the photovoltaic inverter DC-side arcing fault detection method according to any one of claims 1 to 4.

9. A computer-readable storage medium storing a computer program / instructions, characterized in that, The computer program / instructions are programmed or configured to execute the steps of the photovoltaic inverter DC side arcing fault detection method according to any one of claims 1 to 4 via a processor.

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