Photovoltaic power generation system fault identification method based on parallel arc fault constraint

Abstract

The invention discloses a parallel arc fault constrained photovoltaic power generation system fault identification method, which relates to the technical field of photovoltaic power generation and comprises the following steps: analyzing external characteristics of a photovoltaic cell under a parallel arc fault; according to the external characteristics of the photovoltaic cell, comprehensively considering the voltage and current characteristics of the parallel arc and the output characteristics of the photovoltaic cell, and establishing a parallel arc constraint system model and control characteristics; and obtaining a parallel arc fault identification result according to the parallel arc constraint system model and the control characteristics. According to the invention, the parallel arc fault detection result can be rapidly and accurately detected and identified.

Description

Technical Field

[0001] This invention relates to a fault identification method for photovoltaic power generation systems with parallel arc fault constraints, belonging to the field of photovoltaic power generation technology. Background Technology

[0002] With the increasing depletion of traditional fossil fuels and the continuous deterioration of the ecological environment, countries are accelerating the transition of their energy structures towards renewable energy. As a typical representative of clean energy, photovoltaic (PV) power generation technology, with its advantages of abundant resources, zero pollution, and wide distribution, has become a mainstay in the new energy field. However, with the popularization of PV power generation technology, the probability of failure has also greatly increased, especially arcing faults. Arcing faults not only lead to a decrease in system efficiency but can also cause safety hazards such as fires, seriously threatening the stable operation of PV systems and the safety of people and property. Parallel arcing faults, as a common type of arcing fault, are particularly hazardous. However, existing fault detection and identification methods still have many shortcomings in dealing with parallel arcing faults, making it difficult to meet the needs of practical applications.

[0003] Traditional arc fault detection methods primarily rely on time-domain and frequency-domain analysis of the transient waveform of the Boost input current. However, this method is ineffective for identifying parallel arc faults because they may initially manifest as only slight current changes, making accurate identification difficult through simple time-domain and frequency-domain analysis. Furthermore, photovoltaic power generation systems are significantly affected by external factors such as sunlight intensity and ambient temperature, leading to substantial fluctuations in current and voltage during normal system operation. This further complicates fault identification based on time-domain and frequency-domain analysis.

[0004] To address the complexity and diversity of parallel arc faults, some scholars have proposed fault detection schemes based on multi-sensor fusion. By installing multiple sensors, such as current sensors, voltage sensors, and temperature sensors, in the photovoltaic system, the operating status of the system can be monitored in real time to improve the accuracy of fault detection. However, this approach suffers from high sensor costs, complex installation, and difficulties in data fusion, limiting its application in large-scale photovoltaic systems. Furthermore, multi-sensor fusion schemes still struggle to achieve rapid and accurate identification of parallel arc faults when faced with complex fault scenarios.

[0005] In recent years, with the development of signal processing technology and intelligent algorithms, some scholars have used feature extraction and pattern recognition to detect arc faults. However, these methods usually require a large amount of fault sample data for training, and the fault characteristics may differ under different types of photovoltaic power generation systems or different operating conditions, resulting in insufficient model generalization ability and making it difficult to widely promote them in practical applications.

[0006] In the area of ​​fault identification algorithms, some scholars have attempted to use machine learning algorithms, such as support vector machines and neural networks, to classify and identify arc faults. While these algorithms have improved the accuracy of fault identification to some extent, they have high computational resource requirements and are insufficient in terms of real-time performance. Especially in large-scale distributed photovoltaic power generation systems, the sheer volume of data makes real-time processing and analysis extremely difficult, making it hard to meet the requirements for rapid fault detection. Furthermore, the training process of machine learning algorithms requires a large amount of labeled data, and obtaining high-quality labeled arc fault data is often difficult in practical applications, which also limits their effectiveness in fault identification.

[0007] In summary, existing methods for detecting and identifying parallel arc faults still have many limitations in terms of accuracy, real-time performance, generalization ability, and cost-effectiveness. Therefore, there is an urgent need for a parallel arc fault identification method based on a unified model that can comprehensively consider the electrical characteristics, operating environment, and fault features of photovoltaic power generation systems, enabling rapid and accurate detection and identification of parallel arc faults, and providing strong protection for the safe operation of photovoltaic systems. Summary of the Invention

[0008] The purpose of this invention is to provide a method for fault identification in a photovoltaic power generation system constrained by parallel arc faults. By establishing a photovoltaic system model constrained by parallel arc faults, analyzing the external characteristics of photovoltaic cells under parallel arc faults, establishing a parallel arc constraint system model and control characteristics, and identifying the parallel arc fault detection results based on the parallel arc constraint system model and control characteristics.

[0009] To achieve the above objectives, the present invention is implemented using the following technical solution.

[0010] On one hand, the present invention provides a fault identification method for a photovoltaic power generation system with parallel arc fault constraints, comprising:

[0011] Analyze the external characteristics of photovoltaic cells under parallel arc faults;

[0012] Based on the external characteristics of the photovoltaic cell, and taking into account the voltage and current characteristics of the parallel arc and the output characteristics of the photovoltaic cell, a parallel arc constraint system model and control characteristics are established.

[0013] Based on the parallel arc constraint system model and control characteristics, the parallel arc fault identification results are obtained.

[0014] Optionally, the photovoltaic cell external characteristic analysis process under parallel arc fault is as follows: When a parallel arc fault occurs on the photovoltaic bus, the current branch generated by the parallel arc affects the overall external characteristics of the photovoltaic system; the distance between the two poles of the parallel arc decreases, the power loss increases, and the output power of the photovoltaic parallel arc system gradually decreases; the external characteristics of the photovoltaic cell under arc fault are expressed as:

[0015] ;

[0016] In the formula: This refers to the current excited by photons in a photovoltaic cell, and its value depends on the level of sunlight, the area of ​​the solar panel, and the temperature. and The equivalent parallel and series resistances of the photovoltaic cell; This is the saturation current in the absence of light. The charge of an electron is , and its magnitude is . K is the Boltzmann constant, with a magnitude of A is a constant factor, which is 1 when the forward bias voltage is large and 2 when the forward bias voltage is small; T is the temperature of the photovoltaic cell. For fault gap current, and These are the load current and voltage, respectively.

[0017] Optionally, the establishment of the parallel electric arc constraint system model and control characteristics is classified according to the distance between the two poles of the electric arc, and the control characteristics are obtained according to the different cases of the distance between the two poles of the electric arc.

[0018] Optionally, the classification based on the distance between the two electrodes of the electric arc includes three cases;

[0019] Scenario 1: At this time, the MPPT current (the current when the photovoltaic array operates at its maximum power point) is greater than the arc current carrying capacity, and the photovoltaic bus controls the MPPT voltage (the voltage when the photovoltaic array operates at its maximum power point) through the Boost converter; where, The critical arc spacing for the occurrence of parallel arcs in the circuit. The critical arc spacing is the point at which all bus current flows into the arc branch.

[0020] Input voltage of Boost converter The control characteristics are:

[0021] ;

[0022] The input current control characteristic is as follows: the MPPT current of the photovoltaic cell is greater than the arc current transfer capability, the photovoltaic cell operates in MPPT mode, and the input current of the Boost converter is... for:

[0023] ;

[0024] The power control characteristics are: Boost converter input power With parallel arc loss power They are respectively:

[0025] ;

[0026] In the formula, This represents the transmission limit of the arc current under the condition of a fixed distance between two electrodes. and This represents the current and voltage of the photovoltaic array at its maximum power point.

[0027] Scenario 2: At that time, the arc current transfer capability is between the MPPT current of the photovoltaic array and the maximum current of the photovoltaic array; where, The critical arc spacing that Boost can maintain the bus voltage means that the bus voltage is constrained by the arc when the distance is less than this.

[0028] The input voltage characteristics of the Boost converter are:

[0029] = ;

[0030] The input current characteristics of the Boost converter are:

[0031] ;

[0032] The power control characteristic is that all the power generated by the photovoltaic array flows into the parallel arc branch;

[0033] Scenario 3: At that time, the arc current transfer capacity is greater than the maximum current of the photovoltaic array;

[0034] The input voltage characteristics of the Boost converter are as follows: at this time, the electric arc will burn violently, and the voltage amplitude of the input Boost is less than 30%;

[0035] The input current characteristics of the Boost converter are as follows: due to the intense burning of the electric arc, the current forms a short circuit through the arc, and the current flowing into the Boost is close to 0.

[0036] The power control characteristic is that the Boost converter can no longer acquire power.

[0037] Optionally, the parallel arc fault identification process is as follows:

[0038] First, obtain the output voltage and output current under Boost-MPPT control. When neither the output voltage nor the output current is zero, determine whether the output current decreases. If it does not decrease and the output voltage does not decrease, then there is no fault and Boost operates normally. If the output current decreases, continue to determine whether the output voltage decreases. If the output voltage does not decrease at this time, it is case one of parallel arcing, and Boost-MPPT control can restore steady state. Otherwise, it is case two and case three of parallel arcing, and Boost needs to perform arc extinguishing control.

[0039] In a second aspect, the present invention provides a fault identification device for a photovoltaic power generation system with parallel arc fault constraint, comprising:

[0040] The photovoltaic cell external characteristic analysis module is used to analyze the external characteristics of photovoltaic cells under parallel arc faults.

[0041] The fault identification module is used to: establish a parallel arc constraint system model and control characteristics based on the external characteristics of the photovoltaic cell, taking into account the voltage and current characteristics of the parallel arc and the output characteristics of the photovoltaic cell;

[0042] Based on the parallel arc constraint system model and control characteristics, the parallel arc fault identification results are obtained.

[0043] Thirdly, the present invention provides a computer-readable storage medium having a computer program / instruction stored thereon, which, when executed by a processor, implements the steps of the photovoltaic power generation system fault identification method with parallel arc fault constraints as described in any of the first aspects.

[0044] Fourthly, the present invention provides a computer device / equipment / system, characterized in that it comprises:

[0045] Memory, used to store computer programs / instructions;

[0046] A processor for executing the computer program / instructions to implement the steps of the photovoltaic power generation system fault identification method with parallel arc fault constraints as described in any of the first aspects.

[0047] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0048] 1. This invention provides a detailed analysis of the external characteristics of photovoltaic parallel arcs, establishes a parallel arc constraint system model and control characteristics, and, based on the parallel arc constraint system model and control characteristics, quickly and accurately detects and identifies parallel arc fault detection results;

[0049] 2. This invention monitors the output voltage and output current, unlike traditional methods that use transient waveform time-domain and frequency analysis of the Boost input current to identify fault types. It is suitable for engineering applications and the implementation process is relatively simple. Attached Figure Description

[0050] Figure 1 This is a flowchart of the photovoltaic power generation system fault identification method with parallel arc fault constraint according to the present invention;

[0051] Figure 2 This is a structural diagram of the photovoltaic power generation system with parallel arc fault constraint according to the present invention;

[0052] Figure 3 This is a structural diagram of the equivalent model for photovoltaic parallel arc faults of the present invention;

[0053] Figure 4 This is a structural diagram of the equivalent average model of the photovoltaic power generation system with parallel arc fault constraints according to the present invention.

[0054] Figure 5 The voltage and current curves are schematic diagrams for cases two and three of the fault identification method for photovoltaic power generation systems with parallel arc fault constraints according to the present invention.

[0055] Figure 6 The diagram shows the logic for identifying and classifying parallel arc faults on the photovoltaic bus in the photovoltaic power generation system fault identification method with parallel arc fault constraints of the present invention. Detailed Implementation

[0056] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0057] Example 1:

[0058] This embodiment introduces a fault identification method for a photovoltaic power generation system with parallel arc fault constraints, such as... Figure 1 As shown, it includes:

[0059] Analyze the external characteristics of photovoltaic cells under parallel arc faults;

[0060] Based on the external characteristics of the photovoltaic cell, and taking into account the voltage and current characteristics of the parallel arc and the output characteristics of the photovoltaic cell, a parallel arc constraint system model and control characteristics are established.

[0061] Based on the parallel arc constraint system model and control characteristics, the parallel arc fault identification results are obtained.

[0062] A photovoltaic power generation system with parallel arc fault constraint, such as Figure 2 As shown, it includes a photovoltaic array, a parallel arc module, a boost converter, and a voltage source load structure;

[0063] The Boost converter includes an inductor, a diode, a switching transistor, an input capacitor, and an output capacitor;

[0064] One end of the photovoltaic array is connected to one end of the parallel arc module, the input terminal of the inductor, and the positive terminal of the input capacitor; the other end of the photovoltaic array is connected to the negative terminals of the input capacitor and the output capacitor, the other end of the parallel arc module, the emitter of the switching transistor, and the negative terminal of the voltage source load structure.

[0065] The output terminal of the inductor is connected to the collector of the switching transistor and the anode of the diode;

[0066] The cathode of the diode is connected to the positive terminal of the output capacitor and the positive terminal of the voltage source load structure.

[0067] The photovoltaic array includes at least one photovoltaic panel, and the photovoltaic panels are connected in series and parallel to form a photovoltaic array.

[0068] The voltage source type load structure is the equivalent load of the primary combiner box and the secondary combiner box connected to the back stage of the photovoltaic array.

[0069] The control method employs a dual closed-loop PI control based on maximum power point tracking (MPPT) of input voltage, inductor, and current to ensure sufficient system response speed and stability. This is achieved through the coordinated operation of the outer loop (voltage loop) and the inner loop (current loop): firstly, the output voltage of the photovoltaic array is detected in real time. and output current The MPPT algorithm calculates the maximum power point based on the detected values ​​and outputs a reference voltage. Then the voltage outer loop PI controller will... With reality Compare the output current reference value. The inner loop PI controller will With reality The final output duty cycle D is compared; this duty cycle D is used by the PWM modulator to generate a control signal; finally, the drive signal is sent to the gate of the switching transistor T in the Boost circuit.

[0070] like Figure 3 As shown, when a parallel arc fault occurs on the photovoltaic bus, the current branch generated by the parallel arc will affect the overall external characteristics of the photovoltaic system when observed from the input port of the photovoltaic converter.

[0071] The analysis process of photovoltaic cell external characteristics under parallel arc fault is as follows: When a parallel arc fault occurs on the photovoltaic bus, the current branch generated by the parallel arc affects the overall external characteristics of the photovoltaic system; the distance between the two poles of the parallel arc decreases, the power loss increases, and the output power of the photovoltaic parallel arc system gradually decreases; the external characteristics of the photovoltaic cell under arc fault are expressed as follows:

[0072] ;

[0073] In the formula: This refers to the current excited by photons in a photovoltaic cell, and its value depends on the level of sunlight, the area of ​​the solar panel, and the temperature. and The equivalent parallel and series resistances of the photovoltaic cell; This is the saturation current in the absence of light. The charge of an electron is , and its magnitude is . K is the Boltzmann constant, with a magnitude of A is a constant factor, which is 1 when the forward bias voltage is large and 2 when the forward bias voltage is small; T is the temperature of the photovoltaic cell. For fault gap current, and These are the load current and voltage, respectively.

[0074] like Figure 4 As shown, the equivalent average model of the parallel arc fault system is established. The parallel arc constraint system model and control characteristics are classified according to the distance between the two arc poles. The control characteristics are obtained according to the different cases of the distance between the two arc poles.

[0075] The classification based on the distance between the two poles of the electric arc includes three cases;

[0076] Scenario 1: At this time, the MPPT current of the photovoltaic array is greater than the arc current carrying capacity, and the photovoltaic bus controls the MPPT voltage through the Boost converter; where, The critical arc spacing for the occurrence of parallel arcs in the circuit. The critical arc spacing is the point at which all bus current flows into the arc branch.

[0077] Input voltage of Boost converter The control characteristics are:

[0078] ;

[0079] The input current control characteristic is as follows: the MPPT current of the photovoltaic cell is greater than the arc current transfer capability, the photovoltaic cell operates in MPPT mode, and the input current of the Boost converter is... for:

[0080] ;

[0081] The power control characteristics are: Boost converter input power With parallel arc loss power They are respectively:

[0082] ;

[0083] In the formula, This represents the transmission limit of the arc current under the condition of a fixed distance between two electrodes. and This represents the current and voltage of the photovoltaic array at its maximum power point.

[0084] Scenario 2: At that time, the arc current transfer capability is between the MPPT current of the photovoltaic array and the maximum current of the photovoltaic array; where, The critical arc spacing that Boost can maintain the bus voltage means that the bus voltage is constrained by the arc when the distance is less than this.

[0085] The input voltage characteristics of the Boost converter are:

[0086] = ;

[0087] The input current characteristics of the Boost converter are:

[0088] ;

[0089] The power control characteristic is that all the power generated by the photovoltaic array flows into the parallel arc branch;

[0090] Scenario 3: At that time, the arc current transfer capacity is greater than the maximum current of the photovoltaic array;

[0091] The input voltage characteristics of the Boost converter are as follows: at this time, the electric arc will burn violently, and the voltage amplitude of the input Boost is less than 30%;

[0092] The input current characteristics of the Boost converter are as follows: due to the intense burning of the electric arc, the current forms a short circuit through the arc, and the current flowing into the Boost is close to 0.

[0093] The power control characteristic is that the Boost converter can no longer acquire power.

[0094] like Figure 5The figure shows the voltage-current characteristic curves for cases two and three. When case two occurs, if the photovoltaic system operates in MPPT mode, all photovoltaic power flows into the parallel arc branch. When the parallel arc's current transfer capacity is in interval I, the photovoltaic bus voltage is controlled by Boost to... Only a small portion of the power can be sent to the Boost converter, i.e. When scenario three occurs, the parallel arc current occurs in interval II, and the Boost converter can no longer obtain power. Regardless of whether it's interval I or interval II, the arc will burn more violently, impacting system safety.

[0095] like Figure 6 As shown, the parallel arc fault identification process is as follows:

[0096] First, obtain the output voltage and output current under Boost-MPPT control. When neither the output voltage nor the output current is zero, determine whether the output current decreases. If it does not decrease and the output voltage does not decrease, then there is no fault and Boost operates normally. If the output current decreases, continue to determine whether the output voltage decreases. If the output voltage does not decrease at this time, it is case one of parallel arcing, and Boost-MPPT control can restore steady state. Otherwise, it is case two and case three of parallel arcing, and Boost needs to perform arc extinguishing control.

[0097] Example 2:

[0098] Based on the same inventive concept as Embodiment 1, this embodiment introduces a fault identification device for a photovoltaic power generation system with parallel arc fault constraint, comprising:

[0099] The photovoltaic cell external characteristic analysis module is used to analyze the external characteristics of photovoltaic cells under parallel arc faults.

[0100] The fault identification module is used to: establish a parallel arc constraint system model and control characteristics based on the external characteristics of the photovoltaic cell, taking into account the voltage and current characteristics of the parallel arc and the output characteristics of the photovoltaic cell;

[0101] Based on the parallel arc constraint system model and control characteristics, the parallel arc fault identification results are obtained.

[0102] The specific functions of each module described above are explained in the relevant content of the method in Embodiment 1, and will not be repeated here.

[0103] Example 3:

[0104] Based on the same inventive concept as other embodiments, this embodiment introduces a computer-readable storage medium storing a computer program / instructions thereon, which, when executed by a processor, implements the steps of the photovoltaic power generation system fault identification method with parallel arc fault constraints as described in any of Embodiment 1.

[0105] Example 4:

[0106] Based on the same inventive concept as other embodiments, this embodiment introduces a computer device / apparatus / system, characterized in that it includes:

[0107] Memory, used to store computer programs / instructions;

[0108] A processor is configured to execute the computer program / instructions to implement the steps of the photovoltaic power generation system fault identification method with parallel arc fault constraints as described in any of Embodiment 1.

[0109] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0110] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0111] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0112] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0113] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for fault identification in a photovoltaic power generation system with parallel arc fault constraints, characterized in that, include: Analyze the external characteristics of photovoltaic cells under parallel arc faults; Based on the external characteristics of the photovoltaic cell, and taking into account the voltage and current characteristics of the parallel arc and the output characteristics of the photovoltaic cell, a parallel arc constraint system model and control characteristics are established. Based on the parallel arc constraint system model and control characteristics, the parallel arc fault identification results are obtained.

2. The method for fault identification of a photovoltaic power generation system with parallel arc fault constraints according to claim 1, characterized in that, The analysis process of photovoltaic cell external characteristics under parallel arc fault is as follows: When a parallel arc fault occurs on the photovoltaic bus, the current branch generated by the parallel arc affects the overall external characteristics of the photovoltaic system; the distance between the two poles of the parallel arc decreases, the power loss increases, and the output power of the photovoltaic parallel arc system gradually decreases; the external characteristics of the photovoltaic cell under arc fault are expressed as follows: ； In the formula: This refers to the current excited by photons in a photovoltaic cell, and its value depends on the level of sunlight, the area of ​​the solar panel, and the temperature. and The equivalent parallel and series resistances of the photovoltaic cell; This is the saturation current in the absence of light. The charge of an electron is , and its magnitude is . K is the Boltzmann constant, with a magnitude of A is a constant factor, which is 1 when the forward bias voltage is large and 2 when the forward bias voltage is small; T is the temperature of the photovoltaic cell. For fault gap current, and These are the load current and voltage, respectively.

3. The method for fault identification of a photovoltaic power generation system with parallel arc fault constraints according to claim 1, characterized in that, The establishment of the parallel electric arc constraint system model and control characteristics is classified according to the distance between the two poles of the electric arc, and the control characteristics are obtained according to the different cases of the distance between the two poles of the electric arc.

4. The method for fault identification of a photovoltaic power generation system with parallel arc fault constraints according to claim 3, characterized in that, The distance between the two poles of the electric arc There are three categories for classification; Scenario 1: At this time, the MPPT current of the photovoltaic array is greater than the arc current carrying capacity, and the photovoltaic bus controls the MPPT voltage through the Boost converter; where, The critical arc spacing for the occurrence of parallel arcs in the circuit. The critical arc spacing is the point at which all bus current flows into the arc branch. Input voltage of Boost converter The control characteristics are: ； The input current control characteristic is as follows: the MPPT current of the photovoltaic cell is greater than the arc current transfer capability, the photovoltaic cell operates in MPPT mode, and the input current of the Boost converter is... for: ； The power control characteristics are: Boost converter input power With parallel arc loss power They are respectively: ； In the formula, This represents the transmission limit of the arc current under the condition of a fixed distance between two electrodes. and This represents the current and voltage of the photovoltaic array at its maximum power point. Scenario 2: At that time, the arc current transfer capability is between the MPPT current of the photovoltaic array and the maximum current of the photovoltaic array; where, The critical arc spacing that Boost can maintain the bus voltage means that the bus voltage is constrained by the arc when the distance is less than this. The input voltage characteristics of the Boost converter are: = ； The input current characteristics of the Boost converter are: ； The power control characteristic is that all the power generated by the photovoltaic array flows into the parallel arc branch; Scenario 3: At that time, the arc current transfer capacity is greater than the maximum current of the photovoltaic array; The input voltage characteristics of the Boost converter are as follows: at this time, the electric arc will burn violently, and the voltage amplitude of the input Boost is less than 30%; The input current characteristics of the Boost converter are as follows: due to the intense burning of the electric arc, the current forms a short circuit through the arc, and the current flowing into the Boost is close to 0. The power control characteristic is that the Boost converter can no longer acquire power.

5. The method for fault identification of a photovoltaic power generation system with parallel arc fault constraints according to claim 4, characterized in that, The parallel arc fault identification process is as follows: First, obtain the output voltage and output current under Boost-MPPT control. When neither the output voltage nor the output current is zero, determine whether the output current decreases. If it does not decrease and the output voltage does not decrease, then there is no fault and Boost operates normally. If the output current decreases, continue to determine whether the output voltage decreases. If the output voltage does not decrease at this time, it is case one of parallel arcing, and Boost-MPPT control is used to restore steady state. Otherwise, it is case two and case three of parallel arcing, and Boost needs to perform arc extinguishing control.

6. A fault identification device for a photovoltaic power generation system with parallel arc fault constraint, characterized in that, include: The photovoltaic cell external characteristic analysis module is used to analyze the external characteristics of photovoltaic cells under parallel arc faults. The fault identification module is used to: establish a parallel arc constraint system model and control characteristics based on the external characteristics of the photovoltaic cell, taking into account the voltage and current characteristics of the parallel arc and the output characteristics of the photovoltaic cell; Based on the parallel arc constraint system model and control characteristics, the parallel arc fault identification results are obtained.

7. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, When the computer program / instruction is executed by the processor, it implements the steps of the photovoltaic power generation system fault identification method with parallel arc fault constraints as described in any one of claims 1 to 5.

8. A computer device / equipment / system, characterized in that, include: Memory, used to store computer programs / instructions; A processor for executing the computer program / instructions to implement the steps of the photovoltaic power generation system fault identification method with parallel arc fault constraints as described in any one of claims 1 to 5.

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