Ash deposition state evaluation method of distributed photovoltaic system

Abstract

The invention discloses a method for evaluating the dust deposition state of a distributed photovoltaic system, and relates to the technical field of new energy, and the method comprises the steps: determining the photovoltaic annual degradation rate of the distributed photovoltaic system according to the historical operation data of the distributed photovoltaic system; fitting the current output power of the distributed photovoltaic system through an output power fitting model according to the current environment state, and correcting an obtained output power fitting value through the photovoltaic annual degradation rate to obtain an output power correction value; according to the output power actual value of the current output power of the distributed photovoltaic system and the output power correction value, evaluating the dust deposition state of the distributed photovoltaic system; by adopting the scheme, the problems that in the prior art, an effective dust deposition monitoring means of a photovoltaic system is lacked at the present stage, distributed photovoltaic state operation and maintenance are not facilitated, and photovoltaic power generation benefits are affected are solved.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and in particular to a method for evaluating the dust accumulation status of a distributed photovoltaic system. Background Art

[0002] Dust usually refers to tiny solid particles with a diameter of less than 500μm. Dust in the air mainly comes from dust raised by airflow and air pollution. These dusts are easily adsorbed on the surface of photovoltaic modules and accumulate over a period of time to form dust. Dust accumulation will reduce the power generation of photovoltaics. In areas with severe pollution, if the dust is not cleaned for a long time, the power generation loss can even reach 50%. Distributed photovoltaics have a wide range of application scenarios. Some distributed photovoltaics built in industrial plants or rural wilderness areas have serious dust accumulation on the surface. Due to construction cost constraints, there is a lack of effective dust accumulation monitoring methods, which is not conducive to the state operation and maintenance of distributed photovoltaics and affects the benefits of photovoltaic power generation.

[0003] Regarding the relevant technologies, there is currently a lack of effective means of monitoring dust accumulation in photovoltaic systems, which is not conducive to the status operation and maintenance of distributed photovoltaics and affects the efficiency of photovoltaic power generation. No effective solution has been proposed yet.

[0004] Therefore, it is necessary to improve the related technology to overcome the above-mentioned defects in the related technology. Summary of the invention

[0005] The embodiment of the present application provides a method for evaluating the dust accumulation status of a distributed photovoltaic system, so as to at least solve the problem in the related technology that there is currently a lack of effective means for monitoring the dust accumulation of photovoltaic systems, which is not conducive to the status operation and maintenance of distributed photovoltaics and affects the efficiency of photovoltaic power generation.

[0006] According to one aspect of an embodiment of the present application, a method for evaluating the dust accumulation status of a distributed photovoltaic system is provided, including: determining an annual photovoltaic degradation rate of the distributed photovoltaic system based on historical operating data of the distributed photovoltaic system; fitting a current output power of the distributed photovoltaic system through an output power fitting model according to a current environmental state, and correcting the obtained output power fitting value through the annual photovoltaic degradation rate to obtain an output power correction value; and evaluating the dust accumulation status of the distributed photovoltaic system based on an actual output power value of the current output power of the distributed photovoltaic system and the output power correction value.

[0007] In an exemplary embodiment, the annual photovoltaic degradation rate of the distributed photovoltaic system is determined based on the historical operation data of the distributed photovoltaic system, including: normalizing the historical operation data to obtain a first dimensionless performance ratio of the output power of the distributed photovoltaic system within a first time interval; cleaning the data of multiple first dimensionless performance ratios according to preset rules to obtain multiple second dimensionless performance ratios; and determining the annual photovoltaic degradation rate based on the multiple second dimensionless performance ratios.

[0008] In an exemplary embodiment, the historical operation data is normalized to obtain a first dimensionless performance ratio of the output power of the distributed photovoltaic system in a first time interval, including: The historical operation data is normalized to obtain the first dimensionless performance ratio, where PR T1 is the first dimensionless performance ratio, T1 is the first time interval, P is the output power of the distributed photovoltaic system, P STC is the rated output power of the distributed photovoltaic system, S POA is the irradiance on the array surface, S ref is the STC irradiance, γ is the temperature coefficient, T cell is the PV module temperature, T ref is the STC temperature, T cell =S POA ·exp(a+b·V)+T, V is wind speed, T is ambient temperature, and a and b are empirical constants.

[0009] In an exemplary embodiment, determining the photovoltaic annual degradation rate according to the plurality of second dimensionless performance ratios comprises: using the formula Calculate the third dimensionless performance ratio of the output power of the distributed photovoltaic system in the second time interval, where PR T2 is the third dimensionless performance ratio, T2 is the second time interval, T2=T1*A; according to the time period, the multiple third dimensionless performance ratios are divided into multiple groups of fourth dimensionless performance ratios, wherein the multiple fourth dimensionless performance ratios in each group of fourth dimensionless performance ratios are respectively located in different time periods, and the time coordinates of the multiple fourth dimensionless performance ratios in different time periods are the same; according to the multiple fourth dimensionless performance ratios in each group of fourth dimensionless performance ratios, the year-on-year degradation rate is calculated to obtain multiple year-on-year degradation rates; according to the multiple year-on-year degradation rates, the photovoltaic annual degradation rate is determined.

[0010] In an exemplary embodiment, the current output power of the distributed photovoltaic system is fitted according to the current environmental state through an output power fitting model, including: acquiring current operating data of the distributed photovoltaic system; determining the environmental category according to the current environmental state, and fitting the output power according to the environmental category and the current operating data through the output power fitting model to obtain the output power fitting value.

[0011] In an exemplary embodiment, the dust accumulation state of the distributed photovoltaic system is evaluated according to the actual output power value of the current output power of the distributed photovoltaic system and the output power correction value, including: Calculate the dust accumulation state index value of the distributed photovoltaic system, where MAPE is the dust accumulation state index value, n is the observation time length, T i is the actual output power value of the i-th day, P i is the output power correction value of the i-th day; and sending a prompt signal to the target object according to the dust accumulation status index value, wherein the prompt signal is used to prompt the target object of the dust accumulation status of the distributed photovoltaic system.

[0012] According to another aspect of an embodiment of the present application, a dust accumulation status evaluation device for a distributed photovoltaic system is also provided, including: a determination module, used to determine the annual photovoltaic degradation rate of the distributed photovoltaic system based on the historical operation data of the distributed photovoltaic system; a correction module, used to fit the current output power of the distributed photovoltaic system through an output power fitting model according to the current environmental state, and correct the obtained output power fitting value through the annual photovoltaic degradation rate to obtain an output power correction value; an evaluation module, used to evaluate the dust accumulation status of the distributed photovoltaic system based on the actual output power value of the current output power of the distributed photovoltaic system and the output power correction value.

[0013] According to another aspect of the embodiment of the present application, a computer-readable storage medium is provided, in which a computer program is stored, wherein the computer program is configured to execute the above-mentioned method for evaluating dust accumulation status of a distributed photovoltaic system when running.

[0014] According to another aspect of an embodiment of the present application, an electronic device is also provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the dust accumulation status assessment method of the distributed photovoltaic system through the computer program.

[0015] According to another aspect of the embodiments of the present application, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps of the method described in each embodiment of the present application are implemented.

[0016] Through the present application, the annual photovoltaic degradation rate of the distributed photovoltaic system is first determined according to the historical operation data of the distributed photovoltaic system; then, the current output power of the distributed photovoltaic system is fitted through the output power fitting model according to the current environmental state to obtain the output power fitting value, and the output power fitting value is corrected by the obtained annual photovoltaic degradation rate to obtain the output power correction value; finally, the dust accumulation state of the distributed photovoltaic system is evaluated in combination with the actual output power value of the current output power and the output power correction value; through the above scheme, in the process of monitoring the dust accumulation state, the influence of the degradation rate of the distributed photovoltaic system is taken into account, so that the evaluated dust accumulation state is more accurate; thereby solving the problem in the related technology that there is a lack of effective dust accumulation monitoring means for photovoltaic systems at this stage, which is not conducive to the state operation and maintenance of distributed photovoltaics and affects the efficiency of photovoltaic power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0019] Figure 1 It is a hardware structure block diagram of a computer terminal of a method for evaluating dust accumulation status of a distributed photovoltaic system according to an embodiment of the present application;

[0020] Figure 2 is a flow chart of a method for evaluating dust accumulation status of a distributed photovoltaic system according to an embodiment of the present application;

[0021] Figure 3 It is a flow chart of a method for evaluating dust accumulation status of a distributed photovoltaic system according to an embodiment of the present application;

[0022] Figure 4 It is a structural block diagram of a dust accumulation status assessment device for a distributed photovoltaic system according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0024] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] The method embodiments provided in the embodiments of the present application can be executed in a computer terminal or a similar computing device. Taking running on a computer terminal as an example, Figure 1 1 is a hardware structure block diagram of a computer terminal of a method for evaluating dust accumulation status of a distributed photovoltaic system according to an embodiment of the present application. Figure 1 As shown, the computer terminal may include one or more ( Figure 1 Only one is shown in the figure) a processor 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor (Central Processing Unit, MCU) or a programmable logic device (Field Programmable Gate Array, FPGA)) and a memory 104 for storing data, wherein the above-mentioned computer terminal may also include a transmission device 106 and an input and output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the above-mentioned computer terminal. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations shown.

[0026] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the dust accumulation state assessment method of the distributed photovoltaic system in the embodiment of the present application. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, to implement the above method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories may be connected to the computer terminal via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0027] A wireless network provided by a communication provider of a computer terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (Radio Frequency, referred to as RF) module, which is used to communicate with the Internet wirelessly.

[0028] In this embodiment, a method for evaluating dust accumulation status of a distributed photovoltaic system is provided. Figure 2 is a flow chart of a method for evaluating dust accumulation status of a distributed photovoltaic system according to an embodiment of the present application. Figure 2 As shown, including:

[0029] Step S202, determining an annual photovoltaic degradation rate of the distributed photovoltaic system according to historical operation data of the distributed photovoltaic system;

[0030] It should be noted that the photovoltaic system works in an exposed environment for a long time. During operation, it will be affected by environmental factors such as light, heat, oxygen, liquid medium, etc., which will cause the material to degrade, thereby affecting its performance and reducing the output power. Therefore, in order to improve the accuracy of the dust accumulation status assessment, the degradation rate of the photovoltaic system is first accurately calculated in this application, and the effect of the degradation rate on the output power is combined to make the monitoring result of the dust accumulation status more accurate.

[0031] Step S204, fitting the current output power of the distributed photovoltaic system through the output power fitting model according to the current environmental state, and correcting the obtained output power fitting value through the photovoltaic annual degradation rate to obtain an output power correction value;

[0032] Step S206 , evaluating the dust accumulation state of the distributed photovoltaic system according to the actual output power value of the current output power of the distributed photovoltaic system and the output power correction value.

[0033] Through the above steps, the annual photovoltaic degradation rate of the distributed photovoltaic system is first determined according to the historical operation data of the distributed photovoltaic system; then, the current output power of the distributed photovoltaic system is fitted through the output power fitting model according to the current environmental state to obtain the output power fitting value, and the output power fitting value is corrected by the obtained annual photovoltaic degradation rate to obtain the output power correction value; finally, the dust accumulation state of the distributed photovoltaic system is evaluated in combination with the actual output power value of the current output power and the output power correction value; through the above scheme, in the process of monitoring the dust accumulation state, the influence of the degradation rate of the distributed photovoltaic system is considered, so that the evaluated dust accumulation state is more accurate; thereby solving the problem in the related technology that there is a lack of effective dust accumulation monitoring means for photovoltaic systems at this stage, which is not conducive to the state operation and maintenance of distributed photovoltaics and affects the efficiency of photovoltaic power generation.

[0034] Optionally, the above-mentioned step S202 can be implemented in the following manner: determining the annual photovoltaic degradation rate of the distributed photovoltaic system based on the historical operation data of the distributed photovoltaic system, including: normalizing the historical operation data to obtain a first dimensionless performance ratio of the output power of the distributed photovoltaic system within a first time interval; performing data cleaning on multiple first dimensionless performance ratios according to preset rules to obtain multiple second dimensionless performance ratios; and determining the annual photovoltaic degradation rate based on the multiple second dimensionless performance ratios.

[0035] Firstly, taking a 6kW distributed photovoltaic system as an example, its historical operation data was collected. Secondly, the historical operation data of the 6kW photovoltaic system was normalized to obtain the dimensionless performance ratio PR (i.e. the first dimensionless performance ratio) of the output power without the influence of irradiance and temperature. The data was cleaned to improve the calculation accuracy. Finally, the daily year-on-year method was used to calculate the annual degradation rate of the distributed photovoltaic system in the region based on multiple second dimensionless performance ratios.

[0036] It should be noted that in the data cleaning process of the embodiment of the present application, abnormal data includes the following three categories: first, data where the irradiator measurement value does not match the array surface irradiance; second, data where the PV array output power is greater than the inverter rated power; third, data where the PR T1 <0.6 or PR T1 >1 data.

[0037] Specifically, the historical operation data is normalized to obtain a first dimensionless performance ratio of the output power of the distributed photovoltaic system in a first time interval, including: T1= The historical operation data is normalized to obtain the first dimensionless performance ratio, where PR T1 is the first dimensionless performance ratio, T1 is the first time interval, P is the output power of the distributed photovoltaic system, P STC is the rated output power of the distributed photovoltaic system, S POA is the irradiance on the array surface, S ref is the STC irradiance, γ is the temperature coefficient, T cell is the PV module temperature, T ref is the STC temperature, T cell =S POA ·exp(a+b·V)+T, V is wind speed, T is ambient temperature, a and b are empirical constants.

[0038] The data normalization method is as follows:

[0039]

[0040] T cell =S POA ·exp(a+b·V)+T.

[0041] Where P represents the output power of the photovoltaic system in kW, PR T1 is the first dimensionless performance ratio, T1 is the first time interval, which is optional and can be set to 15 minutes, P STC is the rated output power of the distributed photovoltaic system, S POA is the irradiance on the array surface, S ref is the STC (Standard Test Conditions) irradiance, γ is the temperature coefficient, T cell is the PV module temperature, T ref is the STC temperature, T cell =S POA ·exp(a+b·V)+T, V is the wind speed, T is the ambient temperature, a and b are both empirical constants, which can be taken as P in this embodiment. STC =6kW, γ=-0.0048, a=-3.64, b=-0.082.

[0042] Based on the above steps, determining the photovoltaic annual degradation rate according to the plurality of second dimensionless performance ratios includes: using the formula Calculate the third dimensionless performance ratio of the output power of the distributed photovoltaic system in the second time interval, where PR T2is the third dimensionless performance ratio, T2 is the second time interval, T2=T1*A; according to the time period, the multiple third dimensionless performance ratios are divided into multiple groups of fourth dimensionless performance ratios, wherein the multiple fourth dimensionless performance ratios in each group of fourth dimensionless performance ratios are respectively located in different time periods, and the time coordinates of the multiple fourth dimensionless performance ratios in different time periods are the same; according to the multiple fourth dimensionless performance ratios in each group of fourth dimensionless performance ratios, the year-on-year degradation rate is calculated to obtain multiple year-on-year degradation rates; according to the multiple year-on-year degradation rates, the photovoltaic annual degradation rate is determined.

[0043] In this embodiment, T1 is 15 minutes, according to the output power value PR every 15 minutes 15min , calculate the daily PR value (i.e. the third dimensionless performance ratio mentioned above), at this time T2 is 1 day, A is 96, and after calculating the third dimensionless performance ratio, further calculate the year-on-year degradation rate. The year-on-year degradation rate is defined as the PR value between the operation of the photovoltaic system on a certain day and the same day of the next year. day (ie PR T2 ), if the data of a certain day is missing in the statistical data, resulting in PR day If the value cannot be calculated, the day will be skipped and not calculated. After obtaining multiple year-on-year degradation rates, the median of all year-on-year degradation rates can be taken as the annual PV degradation rate.

[0044] Optionally, the average value of all year-on-year degradation rates may be taken as the annual photovoltaic degradation rate, or other values ​​such as the mode, which is not limited in this application.

[0045] Optionally, the current output power of the distributed photovoltaic system is fitted according to the current environmental state through an output power fitting model, including: obtaining current operating data of the distributed photovoltaic system; determining the environmental category according to the current environmental state, and fitting the output power according to the environmental category and the current operating data through the output power fitting model to obtain the output power fitting value.

[0046] The process of establishing the output power fitting model of this application includes:

[0047] 1. Collect the operating data of the photovoltaic system in the past few years (i.e. historical operating data), including output power, environmental data, etc.;

[0048] 2. Use the fuzzy C-means clustering algorithm to cluster the data into four categories: sunny, cloudy, overcast, and rainy;

[0049] 3. Establish a lightGBM model, and use the lightGBM model to fit the output power of the photovoltaic system on sunny, cloudy, overcast and rainy days, and train the above-mentioned output power fitting model.

[0050] Therefore, the process of fitting the current output power in the present application includes: first obtaining the current operating data of the distributed photovoltaic system, then determining the environmental category corresponding to the current environmental state (including sunny, cloudy, overcast, rainy, etc.), and then using the trained output power fitting model to perform power fitting in the environmental category in combination with the current operating data to fit the output power fitting value of the distributed photovoltaic system in the environment under ideal conditions.

[0051] Based on the above steps, the dust accumulation state of the distributed photovoltaic system is evaluated according to the actual output power value of the current output power of the distributed photovoltaic system and the output power correction value, including: by formula Calculate the dust accumulation state index value of the distributed photovoltaic system, where MAPE is the dust accumulation state index value, n is the observation time length, T i is the actual output power value of the i-th day, P i is the output power correction value of the i-th day; and sending a prompt signal to the target object according to the dust accumulation status index value, wherein the prompt signal is used to prompt the target object of the dust accumulation status of the distributed photovoltaic system.

[0052] First, by the formula Calculate the mean absolute percentage error (MAPE, Mean Absolute Percentage Error, also known as the dust accumulation status index value mentioned above) between the daily photovoltaic output power correction value and the actual value, where T i is the actual output power value of the i-th day, P i is the output power correction value of the i-th day, and then the dust accumulation status evaluation space is set according to the range of MAPE, as shown in Table 1.

[0053] Table 1

[0054] state MAPE range / % Dust density ρ range / (g / m2) Observation window period / day normal (0,10] / ∞ Mild dust accumulation (10,20] (8.6,19.5] 5 Moderate dust accumulation (20,30] (19.5,32.8] 3 Heavy dust accumulation (30,40] (32.8,46.7] 1 abnormal (40,100] / /

[0055] (1) When MAPE is less than 10%, it is normal and no dust accumulation treatment is required;

[0056] (2) When MAPE is greater than 10% and less than 20%, a mild dust accumulation alarm signal is issued and observed for 5 days. If the dust accumulation level does not decrease for 5 consecutive days (indicating no rain), manual cleaning is required;

[0057] (3) When MAPE is greater than 20% and less than 30%, a moderate dust accumulation alarm signal is issued and the dust accumulation level is observed for 3 days. If the dust accumulation level does not decrease for 3 consecutive days, manual cleaning is required;

[0058] (4) When MAPE is greater than 30% and less than 40%, a severe alarm signal is issued and the dust accumulation level is observed for 1 day. If the dust accumulation level has not decreased after 1 day, manual cleaning is required.

[0059] (5) When MAPE is greater than 40%, it is an abnormal alarm signal and the operation and maintenance personnel are required to go to the site immediately to check and handle it.

[0060] Optionally, an optional method for evaluating dust accumulation status of a distributed photovoltaic system is provided in an embodiment of the present application, such as Figure 3 As shown, the following steps are included:

[0061] 1. Calculate the annual degradation rate of distributed photovoltaic systems.

[0062] Firstly, taking a 6kW distributed photovoltaic system as an example, its historical operation data was collected. Secondly, the 6kW photovoltaic historical operation data was normalized and cleaned to improve the calculation accuracy. Finally, the annual degradation rate of the distributed photovoltaic system in the region was calculated using the daily year-on-year method.

[0063] 2. Establish a distributed photovoltaic system output power fitting model.

[0064] First, the fuzzy C-means (FCM) clustering method is used to cluster the distributed photovoltaic system operation data into four types: sunny, cloudy, overcast, and rainy. Secondly, the lightGBM model is used to fit the photovoltaic output for different weather categories. Finally, according to the number of years of operation of the distributed photovoltaic system, the annual degradation rate calculated in step 1 is proportionally reduced to the output value of the fitting model to obtain the photovoltaic output power correction value in the clean state.

[0065] 3. Evaluation and alarm of dust accumulation status of distributed photovoltaic systems.

[0066] Firstly, the influence of dust density on the surface of the module on the output power of the photovoltaic system was analyzed experimentally. Secondly, the difference between the corrected value and the actual value of the output power was used to evaluate the dust accumulation status of the system. Finally, the dust accumulation status evaluation interval and alarm window period were set to guide the subsequent operation and maintenance cleaning work.

[0067] Through the above method, firstly, the annual degradation rate of photovoltaic power generation was calculated based on the historical operation data of photovoltaic power generation. Secondly, the photovoltaic power generation data was clustered into four types according to weather conditions: sunny, cloudy, overcast and rainy. The lightGBM model was introduced, and the environmental data and photovoltaic output power data were used as training samples. The output power fitting model of the distributed photovoltaic system was established for four different weather conditions. The output of the fitting model was reduced according to the annual degradation rate according to the number of years of photovoltaic power generation, and the corrected value of distributed photovoltaic output power was obtained. Finally, the dust accumulation status of the system was evaluated by analyzing the difference between the corrected value of the output power and the actual value, and a status alarm mechanism was established according to the system status.

[0068] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods of each embodiment of the present application.

[0069] In this embodiment, a device for evaluating the dust accumulation state of a distributed photovoltaic system is also provided, and the device is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made will not be repeated. As used below, the term "module" can implement a combination of software and / or hardware for a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0070] Figure 4 : is a structural block diagram of a dust accumulation state assessment device for a distributed photovoltaic system according to an embodiment of the present application, the device comprising:

[0071] A determination module 42, configured to determine an annual photovoltaic degradation rate of the distributed photovoltaic system according to historical operation data of the distributed photovoltaic system;

[0072] A correction module 44 is used to fit the current output power of the distributed photovoltaic system through an output power fitting model according to the current environmental state, and to correct the obtained output power fitting value through the photovoltaic annual degradation rate to obtain an output power correction value;

[0073] The evaluation module 46 is used to evaluate the dust accumulation state of the distributed photovoltaic system according to the actual output power value of the current output power of the distributed photovoltaic system and the output power correction value.

[0074] Through the above device, the annual photovoltaic degradation rate of the distributed photovoltaic system is first determined according to the historical operation data of the distributed photovoltaic system; then, the current output power of the distributed photovoltaic system is fitted through the output power fitting model according to the current environmental state to obtain the output power fitting value, and the output power fitting value is corrected by the obtained annual photovoltaic degradation rate to obtain the output power correction value; finally, the dust accumulation state of the distributed photovoltaic system is evaluated in combination with the actual output power value of the current output power and the output power correction value; through the above scheme, in the process of monitoring the dust accumulation state, the influence of the degradation rate of the distributed photovoltaic system is considered, so that the evaluated dust accumulation state is more accurate; thereby solving the problem in the related technology that there is a lack of effective dust accumulation monitoring means for photovoltaic systems at this stage, which is not conducive to the state operation and maintenance of distributed photovoltaics and affects the efficiency of photovoltaic power generation.

[0075] Optionally, the above-mentioned determination module 42 is also used to normalize the historical operation data to obtain a first dimensionless performance ratio of the output power of the distributed photovoltaic system within a first time interval; perform data cleaning on multiple first dimensionless performance ratios according to preset rules to obtain multiple second dimensionless performance ratios; and determine the photovoltaic annual degradation rate based on the multiple second dimensionless performance ratios.

[0076] Optionally, the determination module 42 is further configured to use the formula The historical operation data is normalized to obtain the first dimensionless performance ratio, where PR T1 is the first dimensionless performance ratio, T1 is the first time interval, P is the output power of the distributed photovoltaic system, P STC is the rated output power of the distributed photovoltaic system, S POA is the irradiance on the array surface, S ref is the STC irradiance, γ is the temperature coefficient, T cell is the PV module temperature, T ref is the STC temperature, T cell =S POA ·exp(a+b·V)+T, V is wind speed, T is ambient temperature, and a and b are empirical constants.

[0077] Optionally, the determination module 42 is further configured to use the formula Calculate the third dimensionless performance ratio of the output power of the distributed photovoltaic system in the second time interval, where PR T2is the third dimensionless performance ratio, T2 is the second time interval, T2=T1*A; according to the time period, the multiple third dimensionless performance ratios are divided into multiple groups of fourth dimensionless performance ratios, wherein the multiple fourth dimensionless performance ratios in each group of fourth dimensionless performance ratios are respectively located in different time periods, and the time coordinates of the multiple fourth dimensionless performance ratios in different time periods are the same; according to the multiple fourth dimensionless performance ratios in each group of fourth dimensionless performance ratios, the year-on-year degradation rate is calculated to obtain multiple year-on-year degradation rates; according to the multiple year-on-year degradation rates, the photovoltaic annual degradation rate is determined.

[0078] Optionally, the correction module 44 is also used to obtain the current operating data of the distributed photovoltaic system; determine the environmental category according to the current environmental state, and perform output power fitting according to the environmental category and the current operating data through the output power fitting model to obtain the output power fitting value.

[0079] Optionally, the evaluation module 46 is further configured to: Calculate the dust accumulation state index value of the distributed photovoltaic system, where MAPE is the dust accumulation state index value, n is the observation time length, T i is the actual output power value of the i-th day, P i is the output power correction value of the i-th day; and sending a prompt signal to the target object according to the dust accumulation status index value, wherein the prompt signal is used to prompt the target object of the dust accumulation status of the distributed photovoltaic system.

[0080] An embodiment of the present application further provides a computer-readable storage medium, in which a computer program is stored, wherein the computer program is configured to execute the steps of any of the above method embodiments when running.

[0081] Optionally, in this embodiment, the storage medium may be configured to store a computer program for performing the following steps:

[0082] S1, determining the annual photovoltaic degradation rate of the distributed photovoltaic system according to the historical operation data of the distributed photovoltaic system;

[0083] S2, fitting the current output power of the distributed photovoltaic system through an output power fitting model according to the current environmental state, and correcting the obtained output power fitting value through the photovoltaic annual degradation rate to obtain an output power correction value;

[0084] S3, evaluating the dust accumulation state of the distributed photovoltaic system according to the actual output power value of the current output power of the distributed photovoltaic system and the output power correction value.

[0085] In an exemplary embodiment, the computer-readable storage medium may include, but is not limited to, various media that can store computer programs, such as a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk.

[0086] For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary implementation modes, and this embodiment will not be described in detail herein.

[0087] An embodiment of the present application further provides an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0088] Optionally, in this embodiment, the processor may be configured to perform the following steps through a computer program:

[0089] S1, determining the annual photovoltaic degradation rate of the distributed photovoltaic system according to the historical operation data of the distributed photovoltaic system;

[0090] S2, fitting the current output power of the distributed photovoltaic system through an output power fitting model according to the current environmental state, and correcting the obtained output power fitting value through the photovoltaic annual degradation rate to obtain an output power correction value;

[0091] S3, evaluating the dust accumulation state of the distributed photovoltaic system according to the actual output power value of the current output power of the distributed photovoltaic system and the output power correction value.

[0092] In an exemplary embodiment, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.

[0093] An embodiment of the present application further provides a computer program product, comprising a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium stores a computer program product, and when the computer program is executed by a processor, the steps of the method described in each embodiment of the present application are implemented.

[0094] Optionally, in this embodiment, the above computer program may be configured to implement the following steps when executed by a processor:

[0095] S1, determining the annual photovoltaic degradation rate of the distributed photovoltaic system according to the historical operation data of the distributed photovoltaic system;

[0096] S2, fitting the current output power of the distributed photovoltaic system through an output power fitting model according to the current environmental state, and correcting the obtained output power fitting value through the photovoltaic annual degradation rate to obtain an output power correction value;

[0097] S3, evaluating the dust accumulation state of the distributed photovoltaic system according to the actual output power value of the current output power of the distributed photovoltaic system and the output power correction value.

[0098] For specific examples in this embodiment, reference may be made to the examples described in the above embodiments and exemplary implementation modes, and this embodiment will not be described in detail herein.

[0099] Obviously, those skilled in the art should understand that the above modules or steps of the present application can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order from that herein, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present application is not limited to any specific combination of hardware and software.

[0100] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for evaluating dust accumulation status of a distributed photovoltaic system, characterized in that: include: Determine the annual photovoltaic degradation rate of the distributed photovoltaic system according to the historical operation data of the distributed photovoltaic system; According to the current environmental state, the current output power of the distributed photovoltaic system is fitted by an output power fitting model, and the obtained output power fitting value is corrected by the photovoltaic annual degradation rate to obtain an output power correction value; The dust accumulation state of the distributed photovoltaic system is evaluated according to the actual output power value of the current output power of the distributed photovoltaic system and the output power correction value.

2. The method for evaluating dust accumulation status of a distributed photovoltaic system according to claim 1, characterized in that: The photovoltaic annual degradation rate of the distributed photovoltaic system is determined according to the historical operation data of the distributed photovoltaic system, including: Normalizing the historical operation data to obtain a first dimensionless performance ratio of the output power of the distributed photovoltaic system within a first time interval; Performing data cleaning on the plurality of the first dimensionless performance ratios according to a preset rule to obtain a plurality of second dimensionless performance ratios; The photovoltaic annual degradation rate is determined according to the plurality of second dimensionless performance ratios.

3. The method for evaluating dust accumulation status of a distributed photovoltaic system according to claim 2, characterized in that: Normalizing the historical operation data to obtain a first dimensionless performance ratio of the output power of the distributed photovoltaic system in a first time interval includes: By formula The historical operation data is normalized to obtain the first dimensionless performance ratio, where PR T1 is the first dimensionless performance ratio, T1 is the first time interval, P is the output power of the distributed photovoltaic system, P STC is the rated output power of the distributed photovoltaic system, S POA is the irradiance on the array surface, S ref is the STC irradiance, γ is the temperature coefficient, T cell is the PV module temperature, T ref is the STC temperature, T cell =S POA ·exp(a+b·V)+T, V is wind speed, T is ambient temperature, and a and b are empirical constants.

4. The method for evaluating dust accumulation status of a distributed photovoltaic system according to claim 2, characterized in that: Determining the photovoltaic annual degradation rate according to the plurality of second dimensionless performance ratios comprises: By formula Calculate the third dimensionless performance ratio of the output power of the distributed photovoltaic system in the second time interval, where PR T2 is the third dimensionless performance ratio, T2 is the second time interval, T2=T1*A; Dividing the plurality of third dimensionless performance ratios into a plurality of groups of fourth dimensionless performance ratios according to a time period, wherein the plurality of fourth dimensionless performance ratios in each group of fourth dimensionless performance ratios are respectively located in different time periods, and the time coordinates of the plurality of fourth dimensionless performance ratios in different time periods are the same; calculating the year-on-year degradation rate according to a plurality of fourth dimensionless performance ratios in each group of fourth dimensionless performance ratios to obtain a plurality of year-on-year degradation rates; The photovoltaic annual degradation rate is determined based on the multiple year-on-year degradation rates.

5. The method for evaluating dust accumulation status of a distributed photovoltaic system according to claim 1, characterized in that: According to the current environmental state, the current output power of the distributed photovoltaic system is fitted by an output power fitting model, including: Acquiring current operating data of the distributed photovoltaic system; The environment category is determined according to the current environment state, and the output power fitting is performed according to the environment category and the current operation data through the output power fitting model to obtain the output power fitting value.

6. The method for evaluating dust accumulation status of a distributed photovoltaic system according to claim 1, characterized in that: The dust accumulation state of the distributed photovoltaic system is evaluated according to the actual output power value of the current output power of the distributed photovoltaic system and the output power correction value, including: By formula Calculate the dust accumulation state index value of the distributed photovoltaic system, where MAPE is the dust accumulation state index value, n is the observation time length, T i is the actual output power value of the i-th day, P i is the output power correction value of the i-th day; A prompt signal is sent to a target object according to the dust accumulation status indicator value, wherein the prompt signal is used to prompt the target object of the dust accumulation status of the distributed photovoltaic system.

7. A dust accumulation status assessment device for a distributed photovoltaic system, characterized in that: include: A determination module, used to determine the annual photovoltaic degradation rate of the distributed photovoltaic system according to the historical operation data of the distributed photovoltaic system; A correction module, used to fit the current output power of the distributed photovoltaic system through an output power fitting model according to the current environmental state, and correct the obtained output power fitting value through the photovoltaic annual degradation rate to obtain an output power correction value; An evaluation module is used to evaluate the dust accumulation state of the distributed photovoltaic system according to the actual output power value of the current output power of the distributed photovoltaic system and the output power correction value.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein the program executes the method according to any one of claims 1 to 6 when executed.

9. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to execute the method according to any one of claims 1 to 6 through the computer program.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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