Fault diagnosis system and method for photovoltaic power distribution network

Abstract

The invention relates to the technical field of photovoltaic power distribution, and discloses a fault diagnosis system and method for a photovoltaic power distribution network, and the system comprises a power generation data module and an intelligent evaluation module. According to the fault diagnosis system and method for the photovoltaic power distribution network, configuration data of all components of the photovoltaic power distribution network, operation data of all time points and real-time monitoring data of the environment where the components are located are obtained through a power generation data module, a data set is formed, and an intelligent evaluation module analyzes operation indexes of each component of the photovoltaic power distribution network in an ideal state; the intelligent evaluation module flexibly adjusts the evaluation parameter adaptability according to the actual configuration data of the photovoltaic power distribution network, analyzes the difference value between the actual operation data of each component of the photovoltaic power distribution network and the operation index in the ideal state, forms an abnormal data set, and performs the corresponding evaluation according to the actual configuration data of the photovoltaic power distribution network. The intelligent evaluation module judges whether the photovoltaic power distribution network has a fault problem or not, and the fault detection and positioning accuracy is high.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power distribution, and in particular to a fault diagnosis system and method for a photovoltaic power distribution network. Background Art

[0002] Photovoltaic distribution network is a power network that uses photovoltaic power generation technology to convert solar energy into electrical energy and transmits it to the user end through the distribution system. With the growth of global demand for renewable energy, photovoltaic distribution network plays an increasingly important role in the energy structure. Photovoltaic distribution network includes photovoltaic panels, inverters, distribution lines, control systems and energy storage devices. Photovoltaic panels are the core components of photovoltaic distribution network, responsible for directly converting solar energy into DC power. They are usually composed of multiple solar cells connected in series or in parallel to obtain the required voltage and current. The function of the inverter is to convert the DC power generated by photovoltaic panels into AC power, because most electrical equipment and power grids work based on AC power. The performance of the inverter directly affects the efficiency and quality of power conversion. The distribution line includes high-voltage transmission lines, transformers, low-voltage distribution lines, etc., which are responsible for transmitting the AC power output by the inverter to the user end or connecting to the public power grid. The control system is used to monitor and manage the operating status of the entire photovoltaic distribution network, including maximum power point tracking MPPT, load management, fault detection and protection and other functions. In order to balance the supply and demand relationship and improve the flexibility and reliability of the system, the photovoltaic distribution network will be equipped with energy storage devices, such as battery energy storage systems. Due to its special operating environment and technical requirements, the photovoltaic distribution network faces a variety of potential failure risks. Therefore, strengthening fault diagnosis and maintenance work and adopting intelligent and automated technical means are crucial to ensure the efficient and stable operation of the photovoltaic distribution network. Through continuous technological innovation and management optimization, the failure rate can be effectively reduced, the equipment life can be extended, and the overall benefits of photovoltaic power generation can be improved.

[0003] At present, the traditional fault diagnosis system based on photovoltaic distribution network has limited detection capabilities. When faced with complex application scenarios, the evaluation parameters are of low accuracy and poor flexibility and adaptability. In addition, after a single component failure occurs, it may take a long time to complete fault detection and location, affecting the real-time and response speed of the system. Summary of the invention

[0004] 1. Technical issues to be resolved In view of the shortcomings of the prior art, the present invention provides a fault diagnosis system and method for a photovoltaic distribution network, which has the advantages of flexible adjustment of evaluation parameters, strong adaptability, efficient detection and high accuracy of fault positioning, etc., and solves the problems of limited detection capability and poor flexibility and adaptability of traditional fault diagnosis systems based on photovoltaic distribution networks, and long time consumption and low efficiency of fault detection and positioning.

[0005] (II) Technical solution To achieve the above-mentioned object, the present invention provides the following technical solutions: a fault diagnosis system for a photovoltaic distribution network, comprising a photovoltaic distribution network, a power generation data module and an intelligent evaluation module; The photovoltaic distribution network is composed of photovoltaic panels, inverters, distribution lines, control systems and energy storage devices, and each component is interconnected through distribution lines; The power generation data module is composed of a component data unit, a sensor data unit and an environment monitoring unit. The component data unit collects a component data set through a network connection control system. The component data set includes configuration data of all components of the photovoltaic distribution network. The sensor data unit collects an operation data set in real time through a network connection control system. The operation data set includes operation data of all time points of the photovoltaic distribution network. The environment monitoring unit collects an environment data set through a network connection environment monitoring device. The environment data set includes real-time monitoring data of the environment where the photovoltaic distribution network is located. The power generation data module transmits the component data set, the operation data set and the environment data set to the intelligent evaluation module through the network. The intelligent evaluation module consists of an operation analysis unit, a fault analysis unit and an evaluation management unit. The operation analysis unit generates standard production capacity based on the component data set. , conversion efficiency and standard loss rate and transmitted to the fault analysis unit through the network. The fault analysis unit analyzes the fault according to the operation data set and the standard capacity. , conversion efficiency and standard loss rate , analyze and generate abnormal data sets and transmitted to the fault analysis unit through the network. The evaluation management unit is set with a fixed-length monitoring cycle, and then combined with the abnormal data group , determine whether there is a fault problem in the photovoltaic distribution network and generate the corresponding judgment result.

[0006] Preferably, the expression of the component data set is , Represents the configuration data of the photovoltaic panel, which includes the nominal voltage of the panel And the number of panels , Indicates the configuration data of the inverter, including the rated voltage of the input DC power , Rated voltage of output AC power and rated temperature , Indicates the configuration data of the distribution line. The configuration data of the distribution line includes the total length of the line and resistance per unit length , Indicates the configuration data of the control system. The configuration data of the control system is the standard delay time. , Represents the configuration data of the energy storage device, which is the total amount of electric energy .

[0007] Preferably, the expression of the running data set is , to The operating data of the photovoltaic distribution network at each time point in turn includes the DC voltage actually output by the photovoltaic panels, the voltage actually output by the inverter when converting DC power into AC power, and the total amount of electric energy actually received by the energy storage device through the distribution line. Indicates the time point of obtaining running data, 1 to Indicates that the obtained operation data is Group.

[0008] Preferably, the expression of the environmental data set is , to Corresponding to the monitoring data of each time point in the environment where the photovoltaic distribution network is located, Indicates the time point when the monitoring data is obtained. Indicates the temperature of the environment where the photovoltaic distribution network is located, 1 to Indicates that the monitoring data obtained is Group.

[0009] Preferably, the standard capacity The calculation formula is as follows: ; In the formula, Indicates standard capacity, It means the nominal voltage of the solar panel multiplied by the number of solar panels. The total voltage is the standard output capacity of the photovoltaic distribution network per hour.

[0010] Preferably, the standard conversion efficiency The calculation formula is as follows: ; In the formula, represents the standard conversion efficiency, Indicates that the inverter is at rated temperature When the inverter is within the specified range, the percentage of the rated voltage of the input DC power and the rated voltage of the output AC power is the standard conversion efficiency of the inverter.

[0011] Preferably, the standard loss rate The calculation formula is as follows: ; In the formula, represents the standard loss rate, Indicates that the inverter is at rated temperature When the rated voltage of the output AC power is within the range, it is the voltage transmitted in the distribution line. It means the total length of the line multiplied by the resistance per unit length to get the total resistance of the distribution line. The voltage transmitted in the distribution line is multiplied by the total resistance of the distribution line to obtain the total loss of the distribution line. Indicates the total amount of electric energy received by the energy storage device through the distribution line, Indicates that the inverter is at rated temperature When the power distribution line is within the range, the percentage of the total power loss of the distribution line to the total power of the energy storage device is the standard loss rate.

[0012] Preferably, the abnormal data set The calculation process is as follows: Extract the photovoltaic distribution network from the operation data set The running data at each time point is marked as At the same time, the environment data set containing the photovoltaic distribution network is extracted. The monitoring data at each time point is marked as ,in, ; Will The actual DC voltage output by the photovoltaic panel is marked as ,Will The voltage output when the inverter actually converts DC power into AC power is marked as , It also represents the voltage transmitted in the distribution line. The total amount of electric energy actually received by the energy storage device through the distribution line is marked as ; ; In the formula, represents an abnormal data group, Indicates the environment where the photovoltaic distribution network is located. The difference between the temperature at a certain time point and the maximum value within the rated temperature range of the inverter, Indicates the difference between the actual DC voltage output by the photovoltaic panel and the standard capacity. It indicates the percentage of the DC voltage actually output by the photovoltaic panel and the voltage actually output when the inverter converts DC into AC, which is the actual conversion efficiency of the inverter. It represents the difference between the standard conversion efficiency and the actual conversion efficiency. It means the voltage transmitted in the distribution line multiplied by the total resistance of the distribution line, and the actual total loss of the distribution line is obtained. The actual loss rate is the percentage of the actual total loss of the distribution line to the total amount of electric energy actually received by the energy storage device through the distribution line. Indicates the difference between the standard loss rate and the actual loss rate.

[0013] Preferably, the evaluation management unit delays the time length according to the standard of the control system Set up monitoring cycles of the same length. During the detection cycle, if abnormal data sets When the difference between the temperature of the environment where the photovoltaic distribution network is located and the maximum value within the rated temperature range of the inverter is negative, it means that the photovoltaic distribution network inverter has a potential fault. When the difference between the actual DC voltage output by the photovoltaic panels and the standard capacity is negative, it means that there is a fault in the photovoltaic distribution network panels. When the difference between the standard conversion efficiency and the actual conversion efficiency is negative, it means that there is a fault in the photovoltaic distribution network inverter. When the difference between the standard loss rate and the actual loss rate is negative, it means that there are faults in the distribution lines and energy storage devices of the photovoltaic distribution network.

[0014] A fault diagnosis method for a photovoltaic power distribution network comprises the following steps: Step 1: Connect to the photovoltaic distribution network control system through the network to obtain the configuration data of all components of the photovoltaic distribution network, the operation data at all time points, and the real-time monitoring data of the environment, and classify them into component data sets, operation data sets, and environmental data sets in chronological order from early to late; Step 2: Analyze the operating indicators of each component in the PV distribution network under ideal conditions based on the component data set, and generate the corresponding standard capacity , conversion efficiency and standard loss rate ; Step 3: Based on the operating data set and standard capacity , conversion efficiency and standard loss rate , analyze the difference between the actual operating data of each component of the photovoltaic distribution network and the operating indicators under ideal conditions, and form an abnormal data group ; Step 4: Set a detection cycle of the same length according to the delay time of the photovoltaic distribution network control system, and then combine the abnormal data group , to determine whether there is a fault in the photovoltaic distribution network. If the abnormal data group When any value in the value is negative, it means that the PV distribution network component corresponding to the value has a fault problem.

[0015] Compared with the prior art, the present invention provides a fault diagnosis system and method for a photovoltaic distribution network, which has the following beneficial effects: 1. The present invention connects the photovoltaic distribution network control system through the power generation data module network to obtain the configuration data of all components of the photovoltaic distribution network, the operating data at all time points and the real-time monitoring data of the environment, and classifies the component data set, the operating data set and the environmental data set in chronological order from early to late. The intelligent evaluation module analyzes the operating indicators of each component of the photovoltaic distribution network under ideal conditions according to the component data set, and generates the standard production capacity accordingly. , conversion efficiency and standard loss rate ,Different from the simulation prediction results, the intelligent evaluation module provides data support for ,the subsequent measurement of whether the actual operating status is abnormal based on the ,actual configuration data of the photovoltaic distribution network, and has strong ,adaptability by flexibly adjusting the evaluation parameters.

[0016] 2. The present invention uses an intelligent evaluation module to evaluate the operating data set and standard production capacity. , conversion efficiency and standard loss rate , analyze the difference between the actual operating data of each component of the photovoltaic distribution network and the operating indicators under ideal conditions, and form an abnormal data group , and then set the detection cycle of the same length according to the delay time of the photovoltaic distribution network control system, and then combine the abnormal data group , to determine whether there is a fault in the photovoltaic distribution network. If the abnormal data group When any value in is negative, it means that the photovoltaic distribution network component corresponding to the value has a fault problem, and the fault is efficiently detected and located with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the system flow of the present invention; Figure 2 It is a step diagram of the method of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Due to the limited detection capability of the traditional fault diagnosis system based on photovoltaic distribution network, when facing complex application scenarios, the evaluation parameters are of low accuracy and poor flexibility and adaptability. In addition, after a single component failure occurs, it may take a long time to complete the fault detection and location, which affects the real-time performance and response speed of the system. Therefore, a fault diagnosis system and method for photovoltaic distribution network is provided. Please refer to Figure 1-Figure 2 ,The system includes a photovoltaic distribution network, a power generation data module, and an intelligent evaluation module; The photovoltaic distribution network consists of photovoltaic panels, inverters, distribution lines, control systems and energy storage devices, and each component is interconnected through distribution lines; The power generation data module consists of a component data unit, a sensor data unit, and an environmental monitoring unit. The component data unit collects component data sets through a network connection control system. The component data set includes the configuration data of all components in the photovoltaic distribution network. The expression of the component data set is: , Represents the configuration data of the photovoltaic panel, which includes the nominal voltage of the panel And the number of panels The configuration data of photovoltaic panels directly reflects the power generation capacity of photovoltaic panels. Indicates the configuration data of the inverter, including the rated voltage of the input DC power , Rated voltage of output AC power and rated temperature , within the rated temperature range, the inverter can most efficiently convert DC into AC. Indicates the configuration data of the distribution line. The configuration data of the distribution line includes the total length of the line and resistance per unit length , the longer the line length, the higher the total resistance, Indicates the configuration data of the control system. The configuration data of the control system is the standard delay time. ,Control systems usually integrate a huge amount of data. The shorter the delay time, the stronger the fault detection capability, Represents the configuration data of the energy storage device, which is the total amount of electric energy , the total amount of stored electric energy can not only maintain the normal operation of the photovoltaic distribution network, but also provide reliable guarantee for the power supply; The sensor data unit collects the operation data set in real time through the network connection control system. The operation data set includes the operation data of the photovoltaic distribution network at all time points. The expression of the operation data set is: , to The operating data of the photovoltaic distribution network at each time point in turn includes the DC voltage actually output by the photovoltaic panels, the voltage actually output by the inverter when converting DC power into AC power, and the total amount of electric energy actually received by the energy storage device through the distribution line. Indicates the time point of obtaining running data, 1 to Indicates that the obtained operation data is The group collects the operating data of each component of the photovoltaic distribution network in real time, which is conducive to the subsequent rapid determination of the fault point; The environmental monitoring unit collects environmental data sets through network connection to the environmental monitoring device. The environmental data sets include real-time monitoring data of the environment where the photovoltaic distribution network is located. The expression of the environmental data set is: , to Corresponding to the monitoring data of each time point in the environment where the photovoltaic distribution network is located, Indicates the time point when the monitoring data is obtained. Indicates the temperature of the environment where the photovoltaic distribution network is located, 1 to Indicates that the monitoring data obtained is When the ambient temperature is too high, the performance and life of the inverter will be seriously affected, and even the output voltage will be unstable, causing impact on the power grid and causing fire and other accidents; The power generation data module transmits the component data set, the operation data set and the environment data set to the intelligent evaluation module through the network; The intelligent evaluation module consists of an operation analysis unit, a fault analysis unit, and an evaluation management unit. The operation analysis unit analyzes and generates standard production capacity based on the component data set. , conversion efficiency and standard loss rate , and transmitted to the fault analysis unit through the network. The calculation formula is as follows: ; In the formula, Indicates standard capacity, The total voltage obtained by multiplying the nominal voltage of the solar panel by the number of solar panels is the standard output capacity of the photovoltaic distribution network per hour. Different from the simulation estimation result, the intelligent evaluation module digitally evaluates the total capacity of the photovoltaic panels under ideal conditions based on the actual configuration data of the photovoltaic panels, providing data support for the subsequent measurement of whether the actual capacity is abnormal; ; In the formula, represents the standard conversion efficiency, Indicates that the inverter is at rated temperature When the inverter is within the specified range, the percentage of the rated voltage of the input DC power and the rated voltage of the output AC power is the standard conversion efficiency of the inverter, which provides data support for the subsequent measurement of whether the actual conversion efficiency of the inverter is abnormal. ; In the formula, represents the standard loss rate, Indicates that the inverter is at rated temperature When the rated voltage of the output AC power is within the range, it is the voltage transmitted in the distribution line. It means the total length of the line multiplied by the resistance per unit length to get the total resistance of the distribution line. The voltage transmitted in the distribution line is multiplied by the total resistance of the distribution line to obtain the total loss of the distribution line. Indicates the total amount of electric energy received by the energy storage device through the distribution line, Indicates that the inverter is at rated temperature When the power distribution line is within the specified range, the percentage of the total power loss of the distribution line to the total power of the energy storage device is the standard power loss rate, which provides data support for the subsequent measurement of whether the actual power distribution line power loss rate is abnormal. The flexible adjustment of evaluation parameters has strong adaptability. The fault analysis unit is based on the operating data set and standard capacity , conversion efficiency and standard loss rate , analyze and generate abnormal data sets , and transmitted to the fault analysis unit through the network. The calculation process is as follows: Extract the photovoltaic distribution network from the operation data set The running data at each time point is marked as At the same time, the environment data set containing the photovoltaic distribution network is extracted. The monitoring data at each time point is marked as ,in, ; Will The actual DC voltage output by the photovoltaic panel is marked as ,Will The voltage output when the inverter actually converts DC power into AC power is marked as , It also represents the voltage transmitted in the distribution line. The total amount of electric energy actually received by the energy storage device through the distribution line is marked as ; ; In the formula, represents an abnormal data set, Indicates the environment where the photovoltaic distribution network is located. The difference between the temperature at a certain time point and the maximum value within the rated temperature range of the inverter, Indicates the difference between the actual DC voltage output by the photovoltaic panel and the standard capacity. It indicates the percentage of the DC voltage actually output by the photovoltaic panel and the voltage actually output when the inverter converts DC into AC, which is the actual conversion efficiency of the inverter. It represents the difference between the standard conversion efficiency and the actual conversion efficiency. It means the voltage transmitted in the distribution line multiplied by the total resistance of the distribution line, and the actual total loss of the distribution line is obtained. The actual loss rate is the percentage of the actual total loss of the distribution line to the total amount of electric energy actually received by the energy storage device through the distribution line. Indicates the difference between the standard loss rate and the actual loss rate. The abnormal data group includes the comparison results of four dimensions, which provides data support for the subsequent identification and judgment of the fault point of the photovoltaic distribution network; Evaluation management unit according to the control system standard delay time Set up monitoring cycles of the same length. During the detection cycle, if abnormal data sets When the difference between the temperature of the environment where the photovoltaic distribution network is located and the maximum value within the rated temperature range of the inverter is negative, it means that the photovoltaic distribution network inverter has a potential fault. When the difference between the actual DC voltage output by the photovoltaic panels and the standard capacity is negative, it means that there is a fault in the photovoltaic distribution network panels. When the difference between the standard conversion efficiency and the actual conversion efficiency is negative, it means that there is a fault in the photovoltaic distribution network inverter. When the difference between the standard loss rate and the actual loss rate is negative, it means that there are faults in the distribution lines and energy storage devices of the photovoltaic distribution network, and efficient detection and positioning of faults have high accuracy.

[0020] A fault diagnosis method for a photovoltaic power distribution network comprises the following steps: Step 1: Connect to the photovoltaic distribution network control system through the network to obtain the configuration data of all components of the photovoltaic distribution network, the operation data at all time points, and the real-time monitoring data of the environment, and classify them into component data sets, operation data sets, and environmental data sets in chronological order from early to late; Step 2: Analyze the operating indicators of each component in the PV distribution network under ideal conditions based on the component data set, and generate the corresponding standard capacity , conversion efficiency and standard loss rate ,Different from the simulation prediction results, the intelligent evaluation module provides data support for the subsequent measurement of whether the actual operating status is abnormal based on the actual configuration data of the photovoltaic distribution network, and has strong adaptability by flexibly adjusting the evaluation parameters; Step 3: Based on the operating data set and standard capacity , conversion efficiency and standard loss rate , analyze the difference between the actual operating data of each component of the photovoltaic distribution network and the operating indicators under ideal conditions, and form an abnormal data group ; Step 4: Set a detection cycle of the same length according to the delay time of the photovoltaic distribution network control system, and then combine the abnormal data group , to determine whether there is a fault in the photovoltaic distribution network. If the abnormal data group When any value in is negative, it means that the photovoltaic distribution network component corresponding to the value has a fault problem, and the fault is efficiently detected and located with high accuracy.

[0021] Example 1: In this experiment, a photovoltaic distribution network with a total distribution line length of 370 meters and a unit length resistance of 0.5Ω was selected as the experimental object. After testing, in the actual operation of the photovoltaic distribution network, the rated voltage of the inverter output AC power is 220V, and the total amount of electric energy received by the energy storage device through the distribution line is 9698947kWh. The standard loss rate of the photovoltaic distribution network is The calculation formula is as follows: ; In the formula, Indicates the standard loss rate, 220V means the inverter is at rated temperature When the rated voltage of the output AC power is within the range, it is the voltage transmitted in the distribution line. It means the total length of the line multiplied by the resistance per unit length to get the total resistance of the distribution line. It represents the voltage transmitted in the distribution line multiplied by the total resistance of the distribution line, which is the total loss of the distribution line. It is the percentage of the total loss of the distribution line to the total amount of electric energy of the energy storage device. 92% is the standard loss rate of the photovoltaic distribution network.

[0022] Example 2: In this experiment, a photovoltaic distribution network with an inverter rated temperature of 50°C, a standard capacity of 762kWh, a conversion efficiency of 96%, and a standard loss rate of 1.2% was selected as the experimental object. After testing, the photovoltaic distribution network was tested in the actual operation process. The monitoring temperature of the environment was 36°C, the actual capacity of the photovoltaic panel was 981kWh, the inverter conversion efficiency was 95%, and the distribution line loss rate was 1%. The abnormal data set of the photovoltaic distribution network The calculation formula is as follows: ; In the formula, Represents an abnormal data group, including the difference between the actual temperature and the maximum value within the rated temperature range of the inverter, the difference between the actual DC voltage output by the photovoltaic panel and the standard capacity, the difference between the standard conversion efficiency and the actual conversion efficiency, and the difference between the standard loss rate and the actual loss rate.

[0023] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fault diagnosis system for a photovoltaic distribution network, characterized in that: Including photovoltaic distribution network, power generation data module and intelligent evaluation module; The photovoltaic distribution network is composed of photovoltaic panels, inverters, distribution lines, control systems and energy storage devices, and each component is interconnected through distribution lines; The power generation data module is composed of a component data unit, a sensor data unit and an environment monitoring unit. The component data unit collects a component data set through a network connection control system. The component data set includes configuration data of all components of the photovoltaic distribution network. The sensor data unit collects an operation data set in real time through a network connection control system. The operation data set includes operation data of all time points of the photovoltaic distribution network. The environment monitoring unit collects an environment data set through a network connection environment monitoring device. The environment data set includes real-time monitoring data of the environment where the photovoltaic distribution network is located. The power generation data module transmits the component data set, the operation data set and the environment data set to the intelligent evaluation module through the network. The intelligent evaluation module consists of an operation analysis unit, a fault analysis unit and an evaluation management unit. The operation analysis unit generates standard production capacity based on the component data set. , conversion efficiency and standard loss rate and transmitted to the fault analysis unit through the network. The fault analysis unit analyzes the fault according to the operation data set and the standard capacity. , conversion efficiency and standard loss rate , analyze and generate abnormal data sets and transmitted to the fault analysis unit through the network. The evaluation management unit is set with a fixed-length monitoring cycle, and then combined with the abnormal data group , determine whether there is a fault problem in the photovoltaic distribution network and generate the corresponding judgment result.

2. A photovoltaic power distribution network fault diagnosis system according to claim 1, characterized in that: The expression of the component data set is , Represents the configuration data of the photovoltaic panel, which includes the nominal voltage of the panel And the number of panels , Indicates the configuration data of the inverter, including the rated voltage of the input DC power , Rated voltage of output AC power and rated temperature , Indicates the configuration data of the distribution line. The configuration data of the distribution line includes the total length of the line and resistance per unit length , Indicates the configuration data of the control system. The configuration data of the control system is the standard delay time. , Represents the configuration data of the energy storage device, which is the total amount of electric energy .

3. A fault diagnosis system for a photovoltaic power distribution network according to claim 2, characterized in that: The expression of the running data set is , to The operating data of the photovoltaic distribution network at each time point in turn includes the DC voltage actually output by the photovoltaic panels, the voltage actually output by the inverter when converting DC power into AC power, and the total amount of electric energy actually received by the energy storage device through the distribution line. Indicates the time point of obtaining running data, 1 to Indicates that the obtained operation data is Group.

4. A photovoltaic power distribution network fault diagnosis system according to claim 3, characterized in that: The expression of the environmental data set is , to Corresponding to the monitoring data of each time point in the environment where the photovoltaic distribution network is located, Indicates the time point when the monitoring data is obtained. Indicates the temperature of the environment where the photovoltaic distribution network is located, 1 to Indicates that the monitoring data obtained is Group.

5. A photovoltaic power distribution network fault diagnosis system according to claim 4, characterized in that: The standard capacity The calculation formula is as follows: ； In the formula, Indicates standard capacity, It means the nominal voltage of the solar panel multiplied by the number of solar panels. The total voltage is the standard output capacity of the photovoltaic distribution network per hour.

6. A photovoltaic power distribution network fault diagnosis system according to claim 5, characterized in that: The standard conversion efficiency The calculation formula is as follows: ； In the formula, represents the standard conversion efficiency, Indicates that the inverter is at rated temperature When the inverter is within the specified range, the percentage of the rated voltage of the input DC power and the rated voltage of the output AC power is the standard conversion efficiency of the inverter.

7. A photovoltaic power distribution network fault diagnosis system according to claim 6, characterized in that: The standard loss rate The calculation formula is as follows: ； In the formula, represents the standard loss rate, Indicates that the inverter is at rated temperature When the rated voltage of the output AC power is within the range, it is the voltage transmitted in the distribution line. It means the total length of the line multiplied by the resistance per unit length to get the total resistance of the distribution line. The voltage transmitted in the distribution line is multiplied by the total resistance of the distribution line to obtain the total loss of the distribution line. Indicates the total amount of electric energy received by the energy storage device through the distribution line, Indicates that the inverter is at rated temperature When the power distribution line is within the range, the percentage of the total power loss of the distribution line to the total power of the energy storage device is the standard loss rate.

8. A photovoltaic power distribution network fault diagnosis system according to claim 7, characterized in that: The abnormal data set The calculation process is as follows: Extract the photovoltaic distribution network from the operation data set The running data at each time point is marked as At the same time, the environment data set containing the photovoltaic distribution network is extracted. The monitoring data at each time point is marked as ,in, ; Will The actual DC voltage output by the photovoltaic panel is marked as ,Will The voltage output when the inverter actually converts DC power into AC power is marked as , It also represents the voltage transmitted in the distribution line. The total amount of electric energy actually received by the energy storage device through the distribution line is marked as ; ； In the formula, represents an abnormal data set, Indicates the environment where the photovoltaic distribution network is located. The difference between the temperature at a certain time point and the maximum value within the rated temperature range of the inverter, Indicates the difference between the actual DC voltage output by the photovoltaic panel and the standard capacity. It indicates the percentage of the DC voltage actually output by the photovoltaic panel and the voltage actually output when the inverter converts DC into AC, which is the actual conversion efficiency of the inverter. It represents the difference between the standard conversion efficiency and the actual conversion efficiency. It means the voltage transmitted in the distribution line multiplied by the total resistance of the distribution line, and the actual total loss of the distribution line is obtained. The actual loss rate is the percentage of the actual total loss of the distribution line to the total amount of electric energy actually received by the energy storage device through the distribution line. Indicates the difference between the standard loss rate and the actual loss rate.

9. A photovoltaic power distribution network fault diagnosis system according to claim 8, characterized in that: The evaluation management unit delays the control system according to the standard Set up monitoring cycles of the same length. During the detection cycle, if abnormal data sets When the difference between the temperature of the environment where the photovoltaic distribution network is located and the maximum value within the rated temperature range of the inverter is negative, it means that the photovoltaic distribution network inverter has a potential fault. When the difference between the actual DC voltage output by the photovoltaic panels and the standard capacity is negative, it means that there is a fault in the photovoltaic distribution network panels. When the difference between the standard conversion efficiency and the actual conversion efficiency is negative, it means that there is a fault in the photovoltaic distribution network inverter. When the difference between the standard loss rate and the actual loss rate is negative, it means that there are faults in the distribution lines and energy storage devices of the photovoltaic distribution network.

10. A fault diagnosis method for a photovoltaic distribution network, applied to a fault diagnosis system for a photovoltaic distribution network as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Connect to the photovoltaic distribution network control system through the network to obtain the configuration data of all components of the photovoltaic distribution network, the operation data at all time points, and the real-time monitoring data of the environment, and classify them into component data sets, operation data sets, and environmental data sets in chronological order from early to late; Step 2: Analyze the operating indicators of each component in the PV distribution network under ideal conditions based on the component data set, and generate the corresponding standard capacity , conversion efficiency and standard loss rate ; Step 3: Based on the operating data set and standard capacity , conversion efficiency and standard loss rate , analyze the difference between the actual operating data of each component of the photovoltaic distribution network and the operating indicators under ideal conditions, and form an abnormal data group ; Step 4: Set a detection cycle of the same length according to the delay time of the photovoltaic distribution network control system, and then combine the abnormal data group , to determine whether there is a fault in the photovoltaic distribution network. If the abnormal data group When any value in the value is negative, it means that the PV distribution network component corresponding to the value has a fault problem.

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