Distributed photovoltaic risk assessment method and system

Abstract

The invention provides a distributed photovoltaic risk assessment method and system, and relates to the technical field of photovoltaic power generation, and the method comprises the steps: collecting the operation parameters and system environment information of a photovoltaic module, an inverter and energy storage equipment in a distributed photovoltaic system; analyzing an efficiency stability index and a reliability index of the photovoltaic module, a dynamic response index of an inverter and a cycle life index of energy storage equipment based on the current operation parameters; summarizing the indexes into an equipment performance risk value; analyzing a pollution influence index and a shielding influence index based on the current system environment information; summarizing the indexes into an environmental influence risk value; combining the equipment performance risk value with the environmental influence risk value, determining a photovoltaic comprehensive risk value, and further generating a risk level; according to the method, the equipment performance risk index and the environmental influence risk index are comprehensively considered, and the physical characteristics of all the indexes are fully considered, so that the problems that in the prior art, the evaluation indexes are mutually isolated, and the risk evaluation result and the actual situation have large deviation are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation, and in particular to a risk assessment method and system for distributed photovoltaic power generation. Background Art

[0002] With the increasing global demand for clean energy and the increasing maturity of photovoltaic power generation technology, distributed photovoltaic power generation has been widely used as a flexible and efficient way to utilize renewable energy. Distributed photovoltaic power generation systems can be installed in a variety of places such as building roofs, industrial plants, and agricultural greenhouses to achieve local power generation and local consumption, effectively reducing dependence on traditional centralized power generation and improving the safety and reliability of energy supply.

[0003] However, existing distributed photovoltaic risk assessment technologies often focus on some key indicators, such as the efficiency of photovoltaic modules and the reliability of inverters, but do not take other important factors into consideration. In addition, each indicator is usually analyzed in isolation, without fully considering the interrelationship and synergy between different indicators. At the same time, when calculating risk indicators, most existing technologies use relatively simple mathematical models, without fully considering the physical characteristics of each indicator, which leads to deviations between risk assessment results and actual conditions.

[0004] Therefore, there is an urgent need in the art for a distributed photovoltaic risk assessment method and system to solve the above problems. Summary of the invention

[0005] The present invention provides a distributed photovoltaic risk assessment method and system, which can effectively solve the problems existing in the prior art by comprehensively considering equipment performance risk indicators and environmental impact risk indicators and fully considering the physical characteristics of each indicator.

[0006] In one aspect, the present invention provides a distributed photovoltaic risk assessment method, comprising:

[0007] Step 1: Collect operating parameters and system environment information of photovoltaic modules, inverters and energy storage devices in the distributed photovoltaic system;

[0008] Step 2: Analyze the efficiency stability index, reliability index, dynamic response index of the inverter and cycle life index of the energy storage device based on the current operating parameters of the photovoltaic module; summarize the various indicators into the equipment performance risk value;

[0009] Step 3: Analyze the pollution impact index and the shielding impact index based on the current system environmental information; summarize the indicators into an environmental impact risk value;

[0010] Step 4: Combine the equipment performance risk value with the environmental impact risk value to determine the comprehensive photovoltaic risk value, and generate the risk level of the current distributed photovoltaic system based on the preset judgment logic.

[0011] According to a distributed photovoltaic risk assessment method provided by the present invention, the operating parameters and system environment information include:

[0012] The operating parameters of the photovoltaic module include the initial power generation efficiency determined when the photovoltaic module is installed, the current power generation efficiency determined by real-time monitoring, the time span between the initial power generation efficiency and the current power generation efficiency, the number of random inspections within the time span, and the number of faults found within the number of random inspections;

[0013] The operating parameters of the inverter include the actual dynamic response time of the inverter obtained based on real-time monitoring, the ideal dynamic response time determined based on the inverter design specifications, and the time interval from the start to the end of the response;

[0014] The operating parameters of the energy storage device include the capacity of the energy storage device, the daily cycle discharge energy within a preset date before the current day, and the ideal cycle number of the energy storage device;

[0015] The system environmental information includes the total actual power generation of the photovoltaic system obtained based on real-time monitoring, the theoretical power generation determined based on the specification parameters of the photovoltaic components, the current system pollutant concentration data, and the proportion of the blocked photovoltaic panel area in the current system to the total photovoltaic panel area obtained based on real-time monitoring.

[0016] According to a distributed photovoltaic risk assessment method provided by the present invention, the process of analyzing the efficiency stability index and reliability index of photovoltaic components based on current operating parameters includes:

[0017] Definition: The efficiency decay function of light with time f(t) = E ln *e -λt , where E in is the initial power generation efficiency; λ is the decay rate parameter, which is determined by fitting the historical efficiency data;

[0018] Calculate the time span {t 2 , t 1 The average decay rate under Where E cu is the current power generation efficiency;

[0019] The efficiency stability index P is calculated by the first formula es ; The first formula is:

[0020]

[0021] Among them, λ refis the reference value of the decay rate, determined based on the industry standard of similar photovoltaic modules; f ref (t) is the reference decay function, that is, f′(t) and f ref ′(t) are the derivatives of the efficiency decay function and the reference decay function respectively; α pv The efficiency stability adjustment factor of the photovoltaic module is pre-set based on the importance of the actual photovoltaic system and the requirements for efficiency stability;

[0022] Set the second formula based on the time span {t 2 , t 1 The reliability index P is calculated by the number of random inspections within} and the number of faults found within the number of random inspections. r ; The second formula is:

[0023]

[0024] Among them, M total is the number of random inspections, M fail is the number of failures, β pv It is the reliability adjustment factor of the PV module, which is pre-set based on the maintenance conditions of the PV system.

[0025] According to a distributed photovoltaic risk assessment method provided by the present invention, the process of analyzing the dynamic response index of the inverter based on the current operating parameters includes:

[0026] Define the error function of dynamic response time e(t) = |t res -t ideal |; where t res is the actual dynamic response time of the inverter, t ideal is the ideal dynamic response time;

[0027] Calculate the error integral Among them, t 0 and t end They are the response start time and the response end time, which are determined based on the time interval from the start to the end of the response;

[0028] The dynamic response index P is calculated by the third formula e ; The third formula is:

[0029]

[0030] Among them, E ref is the error integral reference value, which is determined based on the industry standard of similar inverters; γ pv It is the inverter dynamic response adjustment coefficient, which is preset based on the dynamic response requirements of the photovoltaic system.

[0031] According to a distributed photovoltaic risk assessment method provided by the present invention, the process of analyzing the cycle life index of the energy storage device based on the current operating parameters includes:

[0032] Define loop depth function Among them, G dis i is the discharge energy on the i-th day, G cap is the capacity of the energy storage device;

[0033] Calculate the equivalent number of cycles Among them, N total is the number of days of the preset date, ω is an empirical parameter;

[0034] The cycle life index S is calculated by the fourth formula cl ; The fourth formula is:

[0035]

[0036] Among them, N des It is a reference value for the number of cycles, which is determined in the specification of the energy storage device; is the average cycle depth, obtained by averaging the cycle depths d(i) of all cycles; is the reference value of the average cycle depth, determined according to the industry standard of similar energy storage equipment; es It is the cycle life adjustment factor of the energy storage equipment, which is pre-set according to the requirements of the photovoltaic system for the cycle life.

[0037] According to a distributed photovoltaic risk assessment method provided by the present invention, each indicator is summarized into an equipment performance risk value, and its summary formula is:

[0038] R ep =P es +P r +P e +S cl

[0039] Among them, R ep is the equipment performance risk value, P es is the stability index, P r is the reliability index, P e is the dynamic response index, S cl It is an indicator of cycle life.

[0040] According to a distributed photovoltaic risk assessment method provided by the present invention, the process of analyzing the pollution impact index and the shading impact index based on the current system environmental information and summarizing the indicators into an environmental impact risk value includes:

[0041] Substitute the collected system environment information into the fifth formula to calculate the pollution impact index Ppi ; The fifth formula is:

[0042]

[0043] Among them, P act is the total actual power generation, P clean is the theoretical power generation, C poll is the pollutant concentration data, C ref is the pollutant concentration reference value, which represents the pre-set acceptable pollutant concentration standard based on local meteorological conditions; k pol It is the pollution impact adjustment factor, which is pre-set according to the sensitivity of the PV system to pollution;

[0044] Substitute the collected system environment information into the sixth formula to calculate the occlusion impact index P oi ; The sixth formula is:

[0045]

[0046] Among them, A ob is the ratio of the area of ​​the photovoltaic panels blocked in the current system to the total area of ​​the photovoltaic panels, A ref is the reference value of the shielding area, which represents the pre-set acceptable shielding area standard based on local meteorological conditions; μ pol The shading effect adjustment coefficient is pre-set according to the sensitivity of the PV system to shading;

[0047] Each indicator is summarized into the environmental impact risk value, and the summary formula is:

[0048] R ei =P pi +P oi

[0049] Among them, R ei is the environmental impact risk value, P pi is the pollution impact index, P oi To block the impact index.

[0050] According to a distributed photovoltaic risk assessment method provided by the present invention, the process of determining the photovoltaic comprehensive risk value and generating the risk level of the current distributed photovoltaic system based on a preset decision logic includes:

[0051] Combined with the equipment performance risk value R ep and environmental impact risk value R ei Calculate the photovoltaic comprehensive risk value R to =R ep +R ei ;

[0052] A number of risk threshold ranges are pre-set, and each risk threshold range corresponds to a risk level from severe to mild in the order of its value from large to small;

[0053] The current photovoltaic comprehensive risk value R to The risk level is matched with the risk threshold range and the corresponding risk level, i.e. the assessment result, is determined based on the matching result.

[0054] In another aspect, the present invention provides a distributed photovoltaic risk assessment system, comprising:

[0055] A data acquisition module, which is connected to the photovoltaic components, inverters, energy storage devices and environmental monitoring equipment, and is used to collect operating parameters and system environmental information of the photovoltaic components, inverters and energy storage devices in the distributed photovoltaic system;

[0056] An equipment performance analysis module, which is connected to the data acquisition module, analyzes the efficiency stability index, reliability index, dynamic response index of the inverter and cycle life index of the energy storage device of the photovoltaic module based on the collected current operating parameters, and summarizes the various indicators into an equipment performance risk value;

[0057] An environmental impact analysis module, which is connected to the data acquisition module, analyzes pollution impact indicators and shielding impact indicators based on the collected current system environmental information, and summarizes each indicator into an environmental impact risk value;

[0058] The comprehensive risk assessment module is connected to the equipment performance analysis module and the environmental impact analysis module, and is used to combine the equipment performance risk value with the environmental impact risk value to determine the photovoltaic comprehensive risk value, and generate the risk level of the current distributed photovoltaic system based on a preset judgment logic.

[0059] Compared with the prior art, the beneficial effects of this application are:

[0060] The present invention not only considers common indicators such as the efficiency of photovoltaic modules and the reliability of inverters, but also comprehensively covers the performance indicators of energy storage equipment, namely the cycle life; at the same time, for environmental influencing factors, the comprehensive impact of local environmental factors such as pollution and shading is deeply analyzed; so that risk assessment can more accurately reflect the actual operating conditions of distributed photovoltaic systems;

[0061] By comprehensively considering equipment performance risk indicators, environmental impact risk indicators and system stability risk indicators, and fully recognizing the interrelationships and synergies between different indicators, it is possible to avoid errors caused by isolated analysis of indicators and improve the accuracy and reliability of risk assessment;

[0062] Since the evaluation indicators of the present invention are comprehensive and take into account the physical properties corresponding to the indicators, the risk assessment results obtained can more accurately reflect the overall risk status of the distributed photovoltaic system; whether it is equipment performance degradation, changes in environmental factors or system stability issues, they can all be reflected in the comprehensive risk value, providing a more reliable basis for decision makers.

[0063] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0064] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0066] Figure 1 It is a schematic flow chart of a distributed photovoltaic risk assessment method provided by an embodiment of the present invention;

[0067] Figure 2 It is a schematic diagram of the structure of a distributed photovoltaic risk assessment system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0068] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0069] Embodiment 1:

[0070] The present invention provides a distributed photovoltaic risk assessment method. Figure 1 ,include:

[0071] Step 1: Collect operating parameters and system environment information of photovoltaic modules, inverters and energy storage devices in the distributed photovoltaic system;

[0072] Step 2: Analyze the efficiency stability index, reliability index, dynamic response index of the inverter and cycle life index of the energy storage device based on the current operating parameters of the photovoltaic module; summarize the various indicators into the equipment performance risk value;

[0073] Step 3: Analyze the pollution impact index and the shielding impact index based on the current system environmental information; summarize the indicators into an environmental impact risk value;

[0074] Step 4: Combine the equipment performance risk value with the environmental impact risk value to determine the comprehensive photovoltaic risk value, and generate the risk level of the current distributed photovoltaic system based on the preset judgment logic.

[0075] The principles and beneficial effects of the above embodiments are as follows: by analyzing various indicators of equipment performance and environmental impact, the risks of distributed photovoltaic systems can be comprehensively evaluated to provide guarantees for the stable operation of the system; detailed analysis of each indicator helps to accurately locate the source of risk, whether it is equipment performance degradation or environmental factors, it can be discovered in time and corresponding measures can be taken; based on the risk assessment results, targeted maintenance and management can be carried out to improve the reliability and stability of distributed photovoltaic systems and extend the service life of equipment; provide a scientific decision-making basis for the planning, design and operation of distributed photovoltaic systems, and reduce investment risks and operating costs.

[0076] In order to further optimize the above embodiment, the operating parameters and system environment information include:

[0077] The operating parameters of the PV modules include the initial power generation efficiency determined when the PV modules are installed, the current power generation efficiency determined through real-time monitoring, the time span between the initial power generation efficiency and the current power generation efficiency, the number of random inspections within the time span, and the number of faults found within the number of random inspections;

[0078] The inverter operating parameters include the actual dynamic response time of the inverter obtained based on real-time monitoring, the ideal dynamic response time determined based on the inverter design specifications, and the time interval from the start to the end of the response;

[0079] The operating parameters of the energy storage device include the capacity of the energy storage device, the daily cycle discharge energy within a preset date before the current day, and the ideal number of cycles of the energy storage device;

[0080] The system environmental information includes the total actual power generation of the photovoltaic system based on real-time monitoring, the theoretical power generation determined based on the specification parameters of the photovoltaic modules, the current system pollutant concentration data, and the proportion of the blocked photovoltaic panel area in the current system to the total photovoltaic panel area based on real-time monitoring.

[0081] It should be noted that the initial power generation efficiency is determined by measuring under standard test conditions after the photovoltaic modules are installed; the current power generation efficiency can be obtained by real-time monitoring of the power sensor installed at the output end of the photovoltaic modules during the operation of the photovoltaic system; the time span can be determined according to the monitoring cycle set by the system, for example, an assessment is conducted once a month or once a quarter, and the time span is the corresponding time period; the number of random inspections can be carried out according to a pre-established random inspection plan, for example, a random inspection is conducted every certain time or a certain number of modules within the time span; the number of failures is obtained by statistically analyzing the failure alarm records of the photovoltaic modules;

[0082] The actual dynamic response time can be determined by applying a specific voltage or current change signal on the input side of the inverter and then monitoring the time required for the output to reach a stable state on the output side; the ideal dynamic response time is obtained according to the design specification of the inverter; the time interval from the start to the end of the response can be obtained by recording the start time of applying the input change signal and the end time of the output reaching a stable state;

[0083] The capacity of the energy storage device is marked on the specification sheet when the device leaves the factory; the daily cycle discharge energy can be monitored in real time by the energy metering device installed at the output end of the energy storage device; the ideal number of cycles is also given in the specification sheet of the energy storage device, or determined according to industry standards based on the type of energy storage device and application scenario;

[0084] The total actual power generation is obtained through real-time monitoring by the power sensor installed at the output end of the photovoltaic system; the theoretical power generation is obtained through theoretical calculation based on the specifications of the photovoltaic modules (such as rated power, conversion efficiency, etc.) and the current environmental conditions such as light and temperature; the current system pollutant concentration data can be obtained through real-time monitoring by pollutant sensors installed around the photovoltaic system; the proportion of the blocked photovoltaic panel area can be obtained through image analysis technology, by processing the real-time image of the photovoltaic system, identifying the blocked photovoltaic panel area, and calculating its proportion of the total photovoltaic panel area.

[0085] In order to further optimize the above embodiment, the process of analyzing the efficiency stability index and reliability index of the photovoltaic module based on the current operating parameters includes:

[0086] Definition: The efficiency decay function of light with time f(t) = E in *e -λt , where E im is the initial power generation efficiency; λ is the decay rate parameter, which is determined by fitting the historical efficiency data;

[0087] Calculate the time span {t 2 , t 1 The average decay rate under Where E cu is the current power generation efficiency;

[0088] The efficiency stability index P is calculated by the first formula es ; The first formula is:

[0089]

[0090] Among them, λ ref is the reference value of the decay rate, determined based on the industry standard of similar photovoltaic modules; f ref(t) is the reference decay function, that is, f′(t) and f ref ′(t) are the derivatives of the efficiency decay function and the reference decay function respectively; α pv The efficiency stability adjustment factor of the photovoltaic module is pre-set based on the importance of the actual photovoltaic system and the requirements for efficiency stability;

[0091] Set the second formula based on the time span {t 2 , t 1 The reliability index P is calculated by the number of random inspections within} and the number of faults found within the number of random inspections. r ; The second formula is:

[0092]

[0093] Among them, M total is the number of random inspections, M fail is the number of failures, β pv It is the reliability adjustment factor of the PV module, which is pre-set based on the maintenance conditions of the PV system.

[0094] It should be noted that the efficiency decay function f(t) simulates the decay process of photovoltaic module efficiency over time. It is determined by fitting the historical efficiency data because the decay trend of photovoltaic module efficiency in practice conforms to the exponential law. By fitting, the decay rate that best fits the actual data can be found. The calculation time span {t 2 , t 1 The average decay rate under In order to obtain the average decay situation in this time period, it can reflect the overall change trend of the component efficiency during this period. The first formula comprehensively considers the comparison between the actual average decay rate and the reference decay rate, as well as the relationship between the derivative of the efficiency decay function and the derivative of the reference decay function. Among them, α pv It is pre-set based on the importance of the actual photovoltaic system and the requirements for efficiency stability. If the photovoltaic system has high requirements for the stability of power generation efficiency, such as in some industrial application scenarios with strict requirements on the quality of power supply, it will be set to a larger value. On the contrary, if the system has relatively low requirements for efficiency stability, such as some small distributed photovoltaic systems used to supplement household electricity, it can be set to a smaller value. Its value range is usually between 0 and 1, and can be adjusted according to actual experience and system requirements.

[0095] Reliability Index P r It is calculated based on the number of random inspections and the number of failures within the time span. In this way, the frequency of failures of PV modules within the time period can be obtained, thereby evaluating their reliability. pvIt is pre-set based on the maintenance status of the PV system. If the PV system has a good maintenance plan and measures, such as regular cleaning, inspection and maintenance of the components, it can be set to a smaller value, because the reliability of the components is relatively high under good maintenance. On the contrary, if the system maintenance is poor, it should be set to a larger value to reflect the higher risk that the components may face. Its value range is usually between 0 and 1, and it is adjusted according to the actual maintenance situation.

[0096] In order to further optimize the above embodiment, the process of analyzing the dynamic response index of the inverter based on the current operating parameters includes:

[0097] Define the error function of dynamic response time e(t) = |t res -t ideal |; where t res is the actual dynamic response time of the inverter, t ideal is the ideal dynamic response time;

[0098] Calculate the error integral Among them, t 0 and t end They are the response start time and the response end time, which are determined based on the time interval from the start to the end of the response;

[0099] The dynamic response index P is calculated by the third formula e ; The third formula is:

[0100]

[0101] Among them, E ref is the error integral reference value, which is determined based on the industry standard of similar inverters; γ pv It is the inverter dynamic response adjustment coefficient, which is preset based on the dynamic response requirements of the photovoltaic system.

[0102] It should be noted that the error function e(t) defines the absolute value of the difference between the actual dynamic response time of the inverter and the ideal dynamic response time. This function intuitively reflects the degree of deviation of the inverter from the ideal situation in terms of dynamic response; the error integral E is the integration of the error function in the time period from the response start time to the response end time. The significance of this integral is that it comprehensively considers the accumulation of errors in the entire dynamic response process. By calculating the error integral, a more comprehensive quantitative indicator of the inverter dynamic response error can be obtained, rather than just focusing on the error value at a certain moment. The third formula comprehensively considers the comparison between the error integral and the error integral reference value, as well as the relative deviation between the actual dynamic response time and the ideal dynamic response time;

[0103] Among them, γ pvIt is pre-set based on the requirements of the PV system for dynamic response. If the PV system has high requirements for the dynamic response speed of the inverter, such as in some application scenarios with strict requirements on power quality, the inverter needs to be able to quickly track changes in light, etc., then it will be set to a larger value. On the contrary, if the system has relatively low requirements for dynamic response speed, such as some small distributed PV systems for simple household electricity use, it can be set to a smaller value. Its value range is usually between 0 and 1, and can be adjusted according to actual experience and system requirements.

[0104] In order to further optimize the above embodiment, the process of analyzing the cycle life index of the energy storage device based on the current operating parameters includes:

[0105] Define loop depth function Among them, G dis i is the discharge energy on the i-th day, G cap is the capacity of the energy storage device;

[0106] Calculate the equivalent number of cycles Among them, N total is the number of days of the preset date, ω is an empirical parameter;

[0107] The cycle life index S is calculated by the fourth formula cl ; The fourth formula is:

[0108]

[0109] Among them, N des It is a reference value for the number of cycles, which is determined in the specification of the energy storage device; is the average cycle depth, obtained by averaging the cycle depths d(i) of all cycles; is the reference value of the average cycle depth, determined according to the industry standard of similar energy storage equipment; es It is the cycle life adjustment factor of the energy storage device, which is pre-set according to the requirements of the photovoltaic system for the cycle life;

[0110] Each indicator is summarized as the equipment performance risk value, and the summary formula is:

[0111] R ep =P es +P r +P e +S cl

[0112] Among them, R ep is the equipment performance risk value, P es is the stability index, P r is the reliability index, P e is the dynamic response index, Scl It is an indicator of cycle life.

[0113] It should be noted that the depth function d(i) reflects the degree of use of the energy storage device during each discharge process, that is, the cycle depth. By monitoring the daily discharge energy and calculating the cycle depth, we can understand the use of the energy storage device at different times. The equivalent number of cycles N equ The calculation of is based on the consideration that the effect of different cycle depths on the life of energy storage equipment is not linear; deeper cycle depths usually have a greater impact on the life of energy storage equipment, so this formula is used to calculate the equivalent number of cycles; among them, for different types of energy storage equipment and application scenarios, the value of ω will be different, which is obtained through a large number of experimental and empirical data summary; by calculating the equivalent number of cycles, the discharge process of different cycle depths can be converted into an equivalent number of cycles concept, so as to better evaluate the overall cycle life of energy storage equipment; the fourth formula comprehensively considers the comparison between the equivalent number of cycles and the reference value of the cycle number, as well as the comparison between the average cycle depth and the reference value of the average cycle depth; among them, ζ es It is pre-set according to the requirements of the photovoltaic system for the cycle life; if the photovoltaic system has very high requirements for the cycle life of the energy storage device, for example, in some application scenarios that are highly dependent on energy storage equipment and require long-term stable operation, such as off-grid distributed photovoltaic systems, then ζ es will be set to a larger value; on the contrary, if the system has relatively low requirements for the cycle life of the energy storage device, such as some distributed photovoltaic systems supported by the power grid, the energy storage device is mainly used to assist in regulating the power quality, then ζ es It can be set to a smaller value; its value range is usually between 0 and 1, and can be adjusted according to actual experience and system requirements;

[0114] By calculating the cycle life index in this way, the cycle life of the energy storage equipment in actual operation can be more accurately evaluated; it takes into account the impact of different cycle depths on the life of the energy storage equipment, as well as the comparison with the design number of cycles and industry standards, and can more comprehensively reflect the remaining service life and health status of the energy storage equipment.

[0115] In order to further optimize the above embodiment, the process of analyzing the pollution impact index and the shielding impact index based on the current system environment information and summarizing the indicators into an environmental impact risk value includes:

[0116] Substitute the collected system environment information into the fifth formula to calculate the pollution impact index P pi ; The fifth formula is:

[0117]

[0118] Among them, P actis the total actual power generation, P clean is the theoretical power generation, C poll is the pollutant concentration data, C ref is the pollutant concentration reference value, which represents the pre-set acceptable pollutant concentration standard based on local meteorological conditions; k pol It is the pollution impact adjustment factor, which is pre-set according to the sensitivity of the PV system to pollution;

[0119] Substitute the collected system environment information into the sixth formula to calculate the occlusion impact index P oi ; The sixth formula is:

[0120]

[0121] Among them, A ob is the ratio of the area of ​​the photovoltaic panels blocked in the current system to the total area of ​​the photovoltaic panels, A ref is the reference value of the shielding area, which represents the pre-set acceptable shielding area standard based on local meteorological conditions; μ pol The shading effect adjustment coefficient is pre-set according to the sensitivity of the PV system to shading;

[0122] Each indicator is summarized into the environmental impact risk value, and the summary formula is:

[0123] R ei =P pi +P oi

[0124] Among them, R ei is the environmental impact risk value, P pi is the pollution impact index, P oi To block the impact index.

[0125] It should be noted that the fifth formula comprehensively considers the difference between the actual power generation and the theoretical power generation and the relationship between the pollutant concentration and the reference concentration; the sixth formula is similar to the pollution impact index formula, and also comprehensively considers the difference between the actual power generation and the theoretical power generation and the relationship between the shielding area and the reference area; this embodiment can quantify the impact of pollution and shielding on the power generation of the photovoltaic system, and provides an important indicator for evaluating the impact of the environment on the system; at the same time, considering the pollution concentration, shielding area and the system's sensitivity to shielding can more accurately reflect the actual situation.

[0126] In order to further optimize the above embodiment, the process of determining the photovoltaic comprehensive risk value and generating the risk level of the current distributed photovoltaic system based on the preset decision logic includes:

[0127] Combined with the equipment performance risk value R ep and environmental impact risk value R eiCalculate the photovoltaic comprehensive risk value R to =R ep +R ei ;

[0128] A number of risk threshold ranges are pre-set, and each risk threshold range corresponds to a risk level from severe to mild in the order of its value from large to small;

[0129] The current photovoltaic comprehensive risk value R to The risk level is matched with the risk threshold range and the corresponding risk level, i.e. the assessment result, is determined based on the matching result.

[0130] It should be noted that the purpose of presetting several risk threshold ranges is to classify the comprehensive risk value of photovoltaics in order to determine the risk level of the system; these threshold ranges are determined based on experience, industry standards and risk tolerance for distributed photovoltaic systems; different risk threshold ranges correspond to different risk levels, arranged in order from high risk to low risk;

[0131] For example, you can set three risk threshold ranges and corresponding risk levels:

[0132] When R to ≥T 1 When the risk level is high, T 1 is a higher threshold; this threshold can be determined based on the system's extreme tolerance to risk. For example, when the comprehensive risk value exceeds this value, the system may frequently fail, seriously affecting power generation efficiency and stability.

[0133] When T 2 <R to <T 1 When the risk level is medium risk, T 2 is a lower than T 1 Within this range, the system may experience some performance degradation, but it will not seriously affect power generation;

[0134] When R to ≤T 2 When the risk level is low, the system runs relatively stably at this risk level and the possibility of performance degradation is small.

[0135] Embodiment 2:

[0136] The embodiment of the present invention provides a distributed photovoltaic risk assessment system, please refer to Figure 2 ,include:

[0137] A data acquisition module, which is connected to the photovoltaic components, inverters, energy storage devices and environmental monitoring equipment, and is used to collect operating parameters and system environmental information of the photovoltaic components, inverters and energy storage devices in the distributed photovoltaic system;

[0138] The equipment performance analysis module is connected to the data acquisition module, and analyzes the efficiency stability index, reliability index, dynamic response index of the inverter and cycle life index of the energy storage device of the photovoltaic module based on the collected current operating parameters, and summarizes each index into an equipment performance risk value;

[0139] The environmental impact analysis module is connected to the data acquisition module, analyzes the pollution impact index and the shielding impact index based on the collected current system environmental information, and summarizes each index into an environmental impact risk value;

[0140] The comprehensive risk assessment module is connected to the equipment performance analysis module and the environmental impact analysis module, and is used to combine the equipment performance risk value with the environmental impact risk value to determine the photovoltaic comprehensive risk value, and generate the risk level of the current distributed photovoltaic system based on the preset judgment logic.

[0141] It should be noted that by analyzing multiple indicators of equipment performance and environmental impact, the risks of distributed photovoltaic systems can be comprehensively assessed to provide guarantees for the stable operation of the system; detailed analysis of each indicator helps to accurately locate the source of risk, whether it is equipment performance degradation or environmental factors, it can be discovered in time and corresponding measures can be taken; based on the risk assessment results, targeted maintenance and management can be carried out to improve the reliability and stability of distributed photovoltaic systems and extend the service life of equipment; provide a scientific decision-making basis for the planning, design and operation of distributed photovoltaic systems, and reduce investment risks and operating costs.

[0142] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A distributed photovoltaic risk assessment method, characterized in that: include: Step 1: Collect operating parameters and system environment information of photovoltaic modules, inverters and energy storage devices in the distributed photovoltaic system; Step 2: Analyze the efficiency stability index, reliability index, dynamic response index of the inverter and cycle life index of the energy storage device based on the current operating parameters of the photovoltaic module; summarize the various indicators into the equipment performance risk value; Step 3: Analyze the pollution impact index and the shielding impact index based on the current system environmental information; summarize the indicators into an environmental impact risk value; Step 4: Combine the equipment performance risk value with the environmental impact risk value to determine the comprehensive photovoltaic risk value, and generate the risk level of the current distributed photovoltaic system based on the preset judgment logic.

2. A distributed photovoltaic risk assessment method according to claim 1, characterized in that: The operating parameters and system environment information include: The operating parameters of the photovoltaic module include the initial power generation efficiency determined when the photovoltaic module is installed, the current power generation efficiency determined by real-time monitoring, the time span between the initial power generation efficiency and the current power generation efficiency, the number of random inspections within the time span, and the number of faults found within the number of random inspections; The operating parameters of the inverter include the actual dynamic response time of the inverter obtained based on real-time monitoring, the ideal dynamic response time determined based on the inverter design specifications, and the time interval from the start to the end of the response; The operating parameters of the energy storage device include the capacity of the energy storage device, the daily cycle discharge energy within a preset date before the current day, and the ideal cycle number of the energy storage device; The system environmental information includes the total actual power generation of the photovoltaic system obtained based on real-time monitoring, the theoretical power generation determined based on the specification parameters of the photovoltaic components, the current system pollutant concentration data, and the proportion of the blocked photovoltaic panel area in the current system to the total photovoltaic panel area obtained based on real-time monitoring.

3. A distributed photovoltaic risk assessment method according to claim 2, characterized in that: The process of analyzing the efficiency stability index and reliability index of the photovoltaic module based on the current operating parameters includes: Definition: The efficiency decay function of light with time f(t) = E in *e -λt , where E in is the initial power generation efficiency; λ is the decay rate parameter, which is determined by fitting the historical efficiency data; Calculate the average decay rate over the time span {t2, t1} Where E cu is the current power generation efficiency; The efficiency stability index P is calculated by the first formula es ; The first formula is: Among them, λ ref is the reference value of the decay rate, determined based on the industry standard of similar photovoltaic modules; f ref (t) is the reference decay function, that is, and f ref ′(t) are the derivatives of the efficiency decay function and the reference decay function respectively; α pv The efficiency stability adjustment factor of the photovoltaic module is pre-set based on the importance of the actual photovoltaic system and the requirements for efficiency stability; Set the second formula to calculate the reliability index P based on the number of random inspections within the time span {t2, t1} and the number of faults found within the random inspections. r ; The second formula is: Among them, M total is the number of random inspections, M fail is the number of failures, β pv It is the reliability adjustment factor of the PV module, which is pre-set based on the maintenance status of the PV system.

4. A distributed photovoltaic risk assessment method according to claim 3, characterized in that: The process of analyzing the dynamic response index of the inverter based on the current operating parameters includes: Define the error function of dynamic response time e(t) = |t res -t ideal |; where t res is the actual dynamic response time of the inverter, t ideal is the ideal dynamic response time; Calculate the error integral Among them, t0 and t end They are the response start time and the response end time, which are determined based on the time interval from the start to the end of the response; The dynamic response index P is calculated by the third formula e ; The third formula is: Among them, E ref is the error integral reference value, which is determined based on the industry standard of similar inverters; γ pv It is the inverter dynamic response adjustment coefficient, which is preset based on the dynamic response requirements of the photovoltaic system.

5. A distributed photovoltaic risk assessment method according to claim 4, characterized in that: The process of analyzing the cycle life index of the energy storage device based on the current operating parameters includes: Define loop depth function Among them, G dis i is the discharge energy on the i-th day, G cap is the capacity of the energy storage device; Calculate the equivalent number of cycles Among them, N total is the number of days of the preset date, ω is an empirical parameter; The cycle life index S is calculated by the fourth formula cl ; The fourth formula is: Among them, N des It is a reference value for the number of cycles, which is determined in the specification of the energy storage device; is the average cycle depth, obtained by averaging the cycle depths d(i) of all cycles; is the reference value of the average cycle depth, determined according to the industry standard of similar energy storage equipment; es It is the cycle life adjustment factor of the energy storage equipment, which is pre-set according to the requirements of the photovoltaic system for the cycle life.

6. A distributed photovoltaic risk assessment method according to claim 5, characterized in that: The indicators are summarized into the equipment performance risk value, and the summary formula is: R ep =P es +P r +P e +S cl Among them, R ep is the equipment performance risk value, P es is the stability index, P r is the reliability index, P e is the dynamic response index, S cl It is an indicator of cycle life.

7. A distributed photovoltaic risk assessment method according to claim 6, characterized in that: The process of analyzing the pollution impact index and the shielding impact index based on the current system environmental information and summarizing the indicators into an environmental impact risk value includes: Substitute the collected system environment information into the fifth formula to calculate the pollution impact index P pi ; The fifth formula is: Among them, P act is the total actual power generation, P clean is the theoretical power generation, C poll is the pollutant concentration data, C ref is the pollutant concentration reference value, which represents the pre-set acceptable pollutant concentration standard based on local meteorological conditions; k pol It is the pollution impact adjustment factor, which is pre-set according to the sensitivity of the PV system to pollution; Substitute the collected system environment information into the sixth formula to calculate the occlusion impact index P oi ; The sixth formula is: Among them, A ob is the ratio of the area of ​​the photovoltaic panels blocked in the current system to the total area of ​​the photovoltaic panels, A ref is the reference value of the shielding area, which represents the pre-set acceptable shielding area standard based on local meteorological conditions; μ pol The shading effect adjustment coefficient is pre-set according to the sensitivity of the PV system to shading; Each indicator is summarized into the environmental impact risk value, and the summary formula is: R ei =P pi +P oi Among them, R ei is the environmental impact risk value, P pi is the pollution impact index, P oi It is an indicator of occlusion impact.

8. A distributed photovoltaic risk assessment method according to claim 7, characterized in that: The process of determining the photovoltaic comprehensive risk value and generating the risk level of the current distributed photovoltaic system based on the preset decision logic includes: Combined with the equipment performance risk value R ep and environmental impact risk value R ei Calculate the photovoltaic comprehensive risk value R to =R ep +R ei ; A number of risk threshold ranges are pre-set, and each risk threshold range corresponds to a risk level from severe to mild in the order of its value from large to small; The current photovoltaic comprehensive risk value R to The risk level is matched with the risk threshold range and the corresponding risk level, i.e. the assessment result, is determined based on the matching result.

9. A distributed photovoltaic risk assessment system, based on the method described in claims 1 to 8, characterized in that: include: A data acquisition module, which is connected to the photovoltaic components, inverters, energy storage devices and environmental monitoring equipment, and is used to collect operating parameters and system environmental information of the photovoltaic components, inverters and energy storage devices in the distributed photovoltaic system; An equipment performance analysis module, which is connected to the data acquisition module, analyzes the efficiency stability index, reliability index, dynamic response index of the inverter and cycle life index of the energy storage device of the photovoltaic module based on the collected current operating parameters, and summarizes the various indicators into an equipment performance risk value; An environmental impact analysis module, which is connected to the data acquisition module, analyzes pollution impact indicators and shielding impact indicators based on the collected current system environmental information, and summarizes each indicator into an environmental impact risk value; The comprehensive risk assessment module is connected to the equipment performance analysis module and the environmental impact analysis module, and is used to combine the equipment performance risk value with the environmental impact risk value to determine the photovoltaic comprehensive risk value, and generate the risk level of the current distributed photovoltaic system based on a preset judgment logic.

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