System for life cycle economy evaluation of rural photovoltaic equipment

Abstract

This invention relates to the field of smart grid technology and discloses a life-cycle economic evaluation system for rural photovoltaic equipment. The system includes: acquiring the overlapping area of ​​the bottom edge retention zone of the photovoltaic module and the bypass diode protection zone to construct spatially segmented economic units and calculating the retention intensity; establishing a material balance equation based on external environmental factors to obtain the dynamic deposition load; converting the load into spectrally weighted transmittance and substituting it into an equivalent circuit model to obtain non-uniform power loss and output power under ash accumulation conditions; calculating the lifespan consumption rate using equivalent operating temperature and dissipation power, and correcting it to obtain the actual output power after aging; determining the marginal economic value by combining electricity load data and calculating the spatially segmented revenue loss; calculating the operation and maintenance and replacement costs caused by local exposure based on the instantaneous failure rate; and finally summarizing various costs and revenue losses based on a discount factor to output a comprehensive life-cycle economic indicator.

Description

Technical Field

[0001] This invention relates to the field of smart grid technology, and more specifically, to a life-cycle economic assessment system for rural photovoltaic equipment. Background Technology

[0002] Photovoltaic power generation systems have been widely used in rural rooftop and courtyard settings. When conducting a full-lifecycle economic assessment of these photovoltaic assets, existing conventional methods typically use the average power generation degradation rate of the entire station, fixed operation and maintenance costs, and component-level residual value to perform a full-process calculation.

[0003] However, in actual operation of rural photovoltaic systems, due to the combined effects of factors such as low-tilt roofs, module metal frames, roof drainage direction, agricultural particulate sources, and natural rainfall and dew, pollutants preferentially accumulate and concentrate at the bottom edge of the modules. This bottom edge area naturally falls within the protection zone of several series-connected cell sub-strings and their bypass diodes. Because of this phenomenon, power generation losses, thermal stress, bypass diode conduction, cleaning costs, partial replacement costs, and residual value reduction do not occur uniformly across the entire module, but rather form a specific non-uniform state along the bottom edge water-stagnant and dust-accumulating zone and the relevant sub-string areas.

[0004] Traditional assessment processes lack detailed measurement methods for the aforementioned non-uniform conditions, making it difficult to calculate changes in local hotspots, bypass diode heat load, and cleaning and disassembly costs caused by the co-location of the bottom edge dust accumulation zone and bypass diode protection zone. They also fail to reasonably reflect the actual mismatch of benefits from residents' self-consumption, resulting in a systematic underestimation or overestimation of the final output net present value, cost per kilowatt-hour, and remaining economic life, making it difficult to reflect the true economic benefits of the equipment in the complex exposure environment of rural areas. Summary of the Invention

[0005] This invention provides a life-cycle economic evaluation system for rural photovoltaic equipment, which solves the technical problems mentioned in the background art.

[0006] This invention provides a life-cycle economic evaluation system for rural photovoltaic (PV) equipment, applicable to PV systems including PV modules and bypass diodes, characterized by its configuration for executing:

[0007] Obtain the geometric region of the retention zone at the bottom edge of the component and the electrical protection region of the diode, find the intersection to construct a spatial segmented economic unit and calculate the retention strength;

[0008] Based on meteorological data and the retention intensity, the dynamic deposition load of the unit is calculated;

[0009] Based on the load, the transmittance is calculated, and combined with the preset clean state power and equivalent circuit model, the dust accumulation state power and non-uniform power loss are calculated.

[0010] Based on the ambient temperature, irradiance and the dissipation power corresponding to the ash accumulation state power, the equivalent operating temperature is obtained, the lifetime consumption rate is calculated, the residual performance factor is obtained to correct the ash accumulation state power, and the actual aging power is obtained.

[0011] The total system power is obtained by summing the actual aging power of each unit, the marginal economic value is calculated by combining the acquired power load data, and the spatial segment revenue loss is calculated by combining the clean state power.

[0012] Based on the lifespan consumption rate and the load-determined failure rate, the segmented operation and maintenance and risk costs are calculated.

[0013] Obtain the discount factor, discount and summarize the cost and the spatial segmented revenue loss, and output the full-cycle comprehensive economic indicator and segmented economic consumption value.

[0014] The beneficial effects of this invention are as follows: By incorporating the non-uniform shading, local temperature rise, and dissipation induced by the co-location of the dust accumulation strip at the bottom edge of rural rooftop photovoltaic systems with the bypass diode substrings into the smallest economic accounting unit, a full-cycle dynamic load and electrical response mapping is established, replacing the traditional evaluation model of average attenuation and fixed operation and maintenance rates for the entire station. This allows for accurate measurement of the dynamic power generation loss, actual lifespan loss, and corresponding costs for cleaning, partial disassembly and reassembly, and mismatched revenue from rural self-consumption along each segment of the equipment. It effectively avoids the inherent defects of traditional evaluation schemes that systematically deviate from the actual net present value, cost per kilowatt-hour, and remaining economic lifespan, providing an objective and reliable evaluation basis for the long-term benefit calculation and refined operation and maintenance planning of rural photovoltaic assets. Attached Figure Description

[0015] Figure 1 This is a flowchart of the workflow of the life-cycle economic evaluation system for rural photovoltaic equipment according to the present invention. Detailed Implementation

[0016] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, features described in some examples may be combined in other examples.

[0017] like Figure 1 As shown, a life-cycle economic evaluation system for rural photovoltaic equipment is applied to photovoltaic systems that include photovoltaic modules and bypass diodes. Its characteristic is that it is configured to perform:

[0018] Obtain the geometric region of the retention zone at the bottom edge of the component and the electrical protection region of the diode, find the intersection to construct a spatial segmented economic unit and calculate the retention strength;

[0019] Based on meteorological data and the retention intensity, the dynamic deposition load of the unit is calculated;

[0020] Based on the load, the transmittance is calculated, and combined with the preset clean state power and equivalent circuit model, the dust accumulation state power and non-uniform power loss are calculated.

[0021] Based on the ambient temperature, irradiance and the dissipation power corresponding to the ash accumulation state power, the equivalent operating temperature is obtained, the lifetime consumption rate is calculated, the residual performance factor is obtained to correct the ash accumulation state power, and the actual aging power is obtained.

[0022] The total system power is obtained by summing the actual aging power of each unit, the marginal economic value is calculated by combining the acquired power load data, and the spatial segment revenue loss is calculated by combining the clean state power.

[0023] Based on the lifespan consumption rate and the load-determined failure rate, the segmented operation and maintenance and risk costs are calculated.

[0024] Obtain the discount factor, discount and summarize the cost and the spatial segmented revenue loss, and output the full-cycle comprehensive economic indicator and segmented economic consumption value.

[0025] This system is applied to photovoltaic systems that include photovoltaic modules and bypass diodes. The system runs on a processing device with numerical calculation capabilities, including but not limited to industrial control computers, cloud computing clusters, and edge computing terminals. The system synchronously acquires meteorological data, photovoltaic module operation data, user electricity load data, and electricity price data through a data acquisition module, and then performs the following steps.

[0026] The intersection of the geometric region of the stagnation zone at the bottom edge of the photovoltaic module and the electrical protection region of the bypass diode is extracted as an overlapping unit, forming a set of spatial segmented economic units composed of all overlapping units, and the unit area is obtained by area integration.

[0027] The formula for calculating the area of ​​a unit is:

[0028]

[0029] in The internal space region corresponding to unit u is defined based on the mapping relationship between the geodetic coordinate system and the component plane coordinate system. The component plane coordinate system is established with the lower left corner of the component as the origin, the direction of the bottom edge of the component as the x-axis, the direction of the side edge of the component as the y-axis, and the z-axis perpendicular to the component plane upward as the z-axis. Let be a differential element of the area integral, with the dimension of square meters; Let u be the area of ​​the unit, measured in square meters. Integration is performed using the trapezoidal integral method. For discrete grid data within the component plane, the unit region is divided into square grids with sides no greater than 1 cm. The areas of all grids completely falling within the unit region, along with the proportion of areas of grids partially falling within the unit region, are summed to obtain the calculated unit area. When the geometric region of the retention zone does not intersect with the electrical protection region, the unit area is set to 0, and this unit is not included in subsequent calculations.

[0030] The geometric region of the retention zone is denoted as The subscript 'm' represents the unique serial number of a single photovoltaic module, corresponding to the contaminant retention area formed by the frame obstruction at the bottom edge of the photovoltaic module. The length of this area along the bottom edge of the module is the same as the length of the bottom edge. The width along the y-axis of the module is calculated using the following formula:

[0031]

[0032] in Let m be the height of the protrusion of the frame of component m relative to the glass surface, in meters. The installation tilt angle of component number m is the angle between the component plane and the horizontal plane, measured in degrees, and ranging from 0 to 90 degrees. The width of the retention band along the y-axis of the component is expressed in meters.

[0033] Electrical protection zones are denoted as The subscript j represents the unique number of the bypass diode in a single module, which corresponds to the coverage area of ​​the series-connected cell substring of a single bypass diode in a single photovoltaic module. The area range is completely consistent with the physical arrangement range of the cells in the corresponding substring. The coordinate boundary of the substring is obtained through the module's factory specification document.

[0034] The surface runoff direction is obtained by subtracting the dot product of the gravity direction vector and the component plane normal vector from the gravity direction vector, multiplying by the component plane normal vector, and then normalizing.

[0035] The formula for calculating the direction of surface runoff is:

[0036]

[0037] Where g is the gravity direction vector, which is taken as a vertically downward unit vector in the geodetic coordinate system, with a dimension of 1; Let be the plane normal vector of the photovoltaic module numbered m. It is a unit vector with a dimension of 1. It is calculated from the module's installation tilt angle and azimuth angle. The z-axis component of the module's plane normal vector is always positive. The L2 norm operation represents the magnitude of a vector. This formula projects the gravity direction vector onto the photovoltaic module plane and then normalizes it to obtain the natural flow direction of fluids such as rainwater and dew within the module plane. The calculated result is a unit vector with a dimension of 1. When the module is installed at a tilt angle of 0 degrees, i.e., when the module is installed horizontally, the magnitude of the denominator is 0. In this case, the surface runoff direction is taken as a unit vector along the bottom edge of the module pointing towards the drain outlet.

[0038] The retention strength is obtained by multiplying the ratio of the height of the protrusion of the frame relative to the glass surface to the sine of the component mounting angle by the absolute value of the inner product of the surface runoff direction and the inner normal vector of the frame, integrating the area within the cell, and then dividing by the ratio of the cell area to the width of the retention zone.

[0039] The formula for calculating retention strength is:

[0040]

[0041] in, Let be the retention intensity corresponding to element u, which is a dimensionless parameter with a value range of [0,1], representing the ability of the boundary within the element region to retain contaminants carried by the fluid. Let m be the height of the protrusion of the frame of component m at position (x,y) relative to the glass surface, in meters; Let m be the width of the retention band of component number m, in meters; , is the surface runoff direction corresponding to component number m, is a unit vector with dimension 1, is calculated from the component installation tilt angle and azimuth angle, and takes the same value throughout the entire component plane; is the inner normal vector of the frame corresponding to the bottom edge of component m. It is a unit vector with a dimension of 1 and its direction points into the glass surface of the component. It is an inherent geometric parameter of the component. This represents absolute value operations. After integration, divide by the area of ​​the unit. The average retention intensity within the unit area is obtained. When the value is 0, the retention strength is taken as 0; when the retention band width is 0... When the value is 0, the retention intensity is taken as 0.

[0042] Based on meteorological data and retention intensity, the dynamic deposition load of the calculation unit is calculated. First, the absolute value of the inner product of rainfall, the catchment area of ​​the unit, and the surface runoff direction with the inner normal vector of the frame is multiplied together. Then, the product of dew, roof runoff contribution, and the corresponding catchment area of ​​the unit is added to obtain the bottom edge catchment volume.

[0043] The formula for calculating the bottom catchment volume is:

[0044]

[0045] in, Let be the water collection volume at the bottom edge of cell u at time t, with the dimension of square meters per second, representing the volume of fluid flowing through a unit length of the bottom edge of the cell per unit time; Let u be the length of the component's base, measured in meters. Let t be the rainfall at time t, in meters per second, obtained through real-time data from meteorological monitoring stations or historical meteorological datasets, with the sampling period consistent with the system's calculation step size; The upstream catchment area of ​​unit u is measured in square meters, corresponding to the surface area within the component plane that can be channeled into the unit u region. It is calculated using the D8 flow convergence algorithm based on the surface runoff direction. Let t be the dew amount at time t, in meters per second, calculated using the Monteith model based on relative humidity, ambient temperature, and dew point temperature from meteorological data. Let t be the contribution of the roof drainage to unit u. It is a dimensionless parameter with a value range of [0,1]. It represents the proportion of the roof drainage to the drainage supply of unit u. It is calculated based on the roof drainage design drawings and the installation position of the components.

[0046] Multiply the mineral dust deposition efficiency, inorganic particle concentration, and particle settling velocity together, and add the product of the agricultural particle deposition efficiency, agricultural particle concentration, and particle settling velocity. Multiply the sum by the unit area to obtain the natural settling increment.

[0047] The formula for calculating the natural settlement increment is:

[0048]

[0049] in Let be the particle settling velocity at time t, in meters per second, calculated using Stokes' law based on particle size and ambient wind speed, with a value ranging from 0.001 to 0.1 meters per second; Let be the mineral dust deposition efficiency corresponding to unit u at time t. is a dimensionless parameter with a value range of [0,1]. It is positively correlated with ambient wind speed and particle size and is obtained by fitting field measured data. The concentration of inorganic particles in the ambient air at time t, in kilograms per cubic meter, is obtained from ambient air quality monitoring data. is the agricultural particle deposition efficiency corresponding to unit u at time t, which is a dimensionless parameter with a value range of [0,1]. It is set for agricultural dust, straw debris and other particles in rural scenarios and is related to the busy farming season and planting type. Let be the concentration of agricultural particles in the ambient air at time t, in kilograms per cubic meter, obtained from data collected at rural environmental monitoring stations. The result of this formula is the increase in sediment volume per unit time in region u due to natural sedimentation, in kilograms per second.

[0050] Multiply the bottom catchment volume by the retention intensity and the concentration of particles carried by the runoff to obtain the runoff interception increment.

[0051] The formula for calculating the runoff interception increment is:

[0052]

[0053] in Let t be the concentration of particles carried by runoff at time t, with the dimension of kilograms per cubic meter. It represents the mass of pollutant particles carried by a unit volume of runoff fluid and is obtained by fitting roof runoff sampling data. The value ranges from 0.001 to 1 kilogram per cubic meter. Let u be the length of the component's base, in meters. The result of this formula is the increase in sediment volume per unit time generated by runoff interception in region u, in kilograms per second.

[0054] The removal rates corresponding to rainfall, dew migration, and manual washing are obtained and summed to obtain the comprehensive removal rate.

[0055] The formula for calculating the overall removal rate is:

[0056]

[0057] in Let be the overall removal rate of cell u at time t, with the dimension of second, representing the proportion of sediment removed from cell u per unit time; Let be the rate at which rainfall removes sediment from unit u at time t, with dimensions in seconds, and positively correlated with rainfall amount and intensity. The calculation formula is: ,in The rainfall erosion coefficient is a dimensionless parameter with a value ranging from 100 to 1000, calibrated using field measurement data. Let be the rate at which dew migration removes sediment from unit u at time t, with dimensions in seconds. This rate is determined by the dew condensation and flow processes caused by diurnal temperature variations, and is calculated using the following formula: ,in is the dew migration coefficient, a dimensionless parameter with a value range of 50 to 500; Let t be the rate at which the sediment is removed from unit u by manual cleaning, measured in seconds, and be a preset value taken during the manual cleaning operation period. Every second, with 0 for non-operational periods.

[0058] The sediment mass change rate is obtained by adding the natural sedimentation increment to the runoff interception increment and subtracting the product of the comprehensive removal rate and the current dynamic sedimentation load. The dynamic sedimentation load is then obtained by integrating the change rate over time.

[0059] The formula for calculating the rate of change of sediment mass is:

[0060]

[0061] in Let be the rate of change of mass of sediment in unit u at time t, with dimensions in kilograms per second; Let be the dynamic sedimentary load within cell u at time t, with dimensions in kilograms, representing the total accumulated sediment mass within the cell region. This first-order linear nonhomogeneous differential equation is integrated in the time domain and solved using the fourth-order Runge-Kutta method. The time step is set to 1 hour; in abrupt changes such as rainfall or artificial washing, the time step is reduced to 1 minute to ensure computational accuracy. Initial time... When the initial value of the dynamic deposition load is 0, the initial value can be calculated from the measured ash thickness and sediment density of the existing photovoltaic system. When the calculated dynamic deposition load is negative, 0 is taken as the output result. It is a time integral infinitesimal element.

[0062] Based on the transmittance calculated using dynamic deposition load, and combined with the preset power in the clean state and the equivalent circuit model, the power in the ash accumulation state and the non-uniform charge loss are calculated. First, the extinction coefficient of the deposit is multiplied by the dynamic deposition load and then divided by the unit area. The negative sign is taken and an exponential operation is performed to obtain the single-wavelength transmittance. The average transmittance is then obtained by weighting.

[0063] The formula for calculating single-wavelength transmittance is:

[0064]

[0065] in The wavelength corresponding to unit u at time t The single-wavelength transmittance is a dimensionless parameter with a value range of [0,1]. For the deposits within unit u at wavelength The extinction coefficient, measured in square meters per kilogram, characterizes the absorption and scattering ability of sediments for specific wavelengths of light. It was obtained by spectrometer measurement of mixed sediment samples in rural settings. The wavelength of the incident light is in nanometers. The calculation and spectral testing range of this system is from 300 nanometers to 1200 nanometers, which fully covers the effective spectral response range of crystalline silicon photovoltaic cells. The test wavelength range is from 300 nanometers to 1200 nanometers, which covers the spectral response range of photovoltaic cells. denoted as mass of sediment per unit area within unit u, in kilograms per square meter.

[0066] The formula for calculating average transmittance is:

[0067]

[0068] in Let be the average transmittance of cell u at time t, and be a dimensionless parameter with a value range of [0,1]. For photovoltaic cells at wavelength The external quantum efficiency is a dimensionless parameter obtained from the component's manufacturer specifications. The integration operation uses the trapezoidal integration method, with a wavelength interval of 1 nanometer.

[0069] The actual local irradiance is obtained by multiplying the irradiance of the tilted surface of the photovoltaic module, the average transmittance, and the spatial distribution coefficient caused by local dust accumulation.

[0070] The formula for calculating the actual local irradiance is:

[0071]

[0072] in Let be the local actual irradiance of unit u at time t, in watts per square meter; Let m be the irradiance of the tilted surface corresponding to the component at time t, in watts per square meter. It is measured by a radiometer installed on the surface of the component, or calculated by using the Hay model in combination with the horizontal irradiance, the tilt angle of the component, and the azimuth angle. is the spatial distribution coefficient of local ash accumulation in unit u at time t. It is a dimensionless parameter with a value range of [0,1]. It characterizes the effect of non-uniform ash accumulation in the unit area on the correction of irradiance. It is linearly increasing from the bottom edge of the component to the inside of the component. It is 0.8 at the bottom edge of the component, 1 at the upper boundary of the retention zone, and 1 for the whole area when uniformly distributed.

[0073] A single diode equivalent circuit model is constructed using the actual local irradiance and preset photoelectric parameters to obtain the terminal voltage and terminal current.

[0074] The current equation for the equivalent circuit model of a single diode is:

[0075]

[0076] in Let t be the terminal current of unit u under terminal voltage V at time t, in amperes; V is the terminal voltage of the photovoltaic substring corresponding to unit u, in volts. Let be the short-circuit current corresponding to element u at time t, with dimensions in amperes, and the calculation formula is: ,in The short-circuit current under standard test conditions. The standard irradiance is 1000 watts per square meter. The standard temperature is 25 degrees Celsius. This is the temperature coefficient of short-circuit current, with dimensions per degree Celsius. Let u be the reverse saturation current corresponding to element u at time t, with dimensions in amperes, and the calculation formula is:

[0077] ;

[0078] in Let q be the reverse saturation current under standard test conditions, and q be the electron charge, with a value of q / q. coulomb, denoted as the bandgap of the semiconductor material, with a value of 1.12 electron volts; n is the diode ideality factor, a dimensionless parameter with a value ranging from 1 to 2. Here is the Boltzmann constant, which takes the value of Electron volts per Kelvin; Let u be the cell temperature corresponding to unit u at time t, in degrees Celsius, and be the equivalent operating temperature calculated. The values ​​are completely consistent, eliminating the need for additional temperature sensors for actual measurement; Let u be the series resistance corresponding to the unit u, with the dimension of ohms; Let u be the parallel resistance corresponding to unit u, with dimensions in ohms. All photoelectric parameters under the above standard test conditions were obtained from the component manufacturer's specifications or calibrated on-site using an outdoor IV tester. The terminal current was calculated using the Newton-Raphson iterative method, with the iterative convergence threshold set to... Ampere, with the maximum number of iterations set to 100.

[0079] Find the extreme point where the difference between the product of the terminal voltage and the terminal current and the power dissipated by the bypass diode reaches its maximum, and define the power corresponding to this extreme point as the power in the dust accumulation state.

[0080] The formula for calculating the power under ash accumulation conditions is:

[0081]

[0082] in Let be the ash accumulation state power of unit u at time t, with the dimension of watts; Let u be the output power of the photovoltaic cell string corresponding to unit u under terminal voltage V, in watts; Let u be the power dissipated by the bypass diode at time t under the terminal voltage V, with dimensions in watts. When the bypass diode is turned off, the power dissipation is the reverse leakage current (denoted as t). The power dissipation is the product of the component's factory reliability test report (in amperes) and the terminal voltage; when the bypass diode is on, the power dissipation is the forward conduction current (denoted as...). The unit is amperes, which is equal to the short-circuit current of the corresponding series-connected battery cell string. The product of the forward voltage drop and the forward voltage drop is taken as 0.7 volts.

[0083] The maximum power point is determined using an improved incremental conductance method, and the steps are as follows:

[0084] The first step is to set the initial terminal voltage. Calculate the initial terminal current as 0.8 times the open-circuit voltage. With initial power The open-circuit voltage is denoted as , refers to the open-circuit voltage of a photovoltaic module under standard test conditions, in volts, which can be obtained from the module's manufacturer specifications or calibrated on-site with an outdoor IV tester;

[0085] The second step is to set the voltage step size. It is 0.005 times the open-circuit voltage, and the updated terminal voltage is... Calculate the corresponding terminal current. With power , The voltage iteration step size for maximum power point tracking is in volts. The basic step size is 0.005 times the open-circuit voltage. When the bypass diode conducts and triggers the hot spot calculation branch, the step size is reduced to 0.001 times the open-circuit voltage.

[0086] The third step is to calculate the conductance increment. ,judge and Is the absolute value of the difference less than the convergence threshold? Siemens, if it is less than, then the current terminal voltage is the maximum power point voltage, and the iteration stops;

[0087] Fourth step: If the difference is greater than the convergence threshold, adjust the direction of the terminal voltage according to the criterion of the incremental conductance method, and repeat the second and third steps until the convergence condition is met or the maximum number of iterations of 50 is reached.

[0088] The fifth step involves simultaneously calculating the power dissipation of the bypass diode during the iteration process. When the bypass diode is turned on, a special calculation branch for hot spots is triggered, reducing the voltage step size to 0.001 times the open-circuit voltage, and re-executing the iterative optimization to avoid getting trapped in a local optimum.

[0089] The difference between the power in the clean state and the power in the dusty state is calculated and integrated in the time domain to obtain the non-uniform power loss.

[0090] The formula for calculating non-uniform charge loss is:

[0091]

[0092] in The non-uniform electrical energy loss corresponding to unit u within the annual time domain y is expressed in kilowatt-hours. Let dt be the clean state power of unit u at time t, with the dimension of watts, which is the maximum output power of unit u when there is no sediment cover. It is calculated using the same equivalent circuit model and maximum power point solution method as the power in the ash accumulation state. The average transmittance is taken as 1 during the calculation. dt is the time integral infinitesimal element with the dimension of hours. is the unit conversion factor from watt-hours to kilowatt-hours. The integration operation is completed within the annual time domain y, using the rectangular integration method. The power loss at each time step is accumulated according to the system calculation step size to obtain the annual cumulative non-uniform power loss.

[0093] The equivalent operating temperature is calculated based on the ambient temperature, irradiance, and dissipation power corresponding to the power under dust accumulation. The lifetime consumption rate is then calculated to obtain the residual performance factor, which is used to correct the power under dust accumulation, thus yielding the actual aging power. First, the difference between the initial value and the local photoelectric conversion efficiency is multiplied by the irradiance of the tilted surface, and then divided by the sum of the products of the zero-order coefficient and the first-order coefficient of heat dissipation of the module and the wind speed, to obtain the photothermal increment. The dissipation power is then divided by the product of the unit area and the local convective heat transfer coefficient to obtain the electrothermal increment. Finally, the ambient temperature, photothermal increment, and electrothermal increment are added together to obtain the equivalent operating temperature.

[0094] The formula for calculating the equivalent operating temperature is:

[0095]

[0096] in Let be the equivalent operating temperature of unit u at time t, in degrees Celsius. Let t be the ambient temperature at time t, in degrees Celsius, obtained from meteorological monitoring data; Let be the local photoelectric conversion efficiency of cell u at time t, where is a dimensionless parameter, and the calculation formula is: ; The zero-order coefficient of heat dissipation for the component corresponding to unit u, with dimensions of watts per square meter per degree Celsius, is calculated using the component's NOCT parameters. The calculation formula is as follows: ,in This refers to the nominal operating cell temperature of the module. The conversion efficiency is under standard test conditions. The ambient temperature under NOCT testing conditions was 20 degrees Celsius. The first-order coefficient for heat dissipation of the component corresponding to unit u is expressed in watts per square meter per degree Celsius per meter per second, and its value ranges from 5 to 25. It is obtained from the component's factory specifications. Let t be the ambient wind speed at time t, measured in meters per second, obtained from meteorological monitoring data; Let u be the local convective heat transfer coefficient corresponding to unit u at time t, with dimensions of watts per square meter per degree Celsius, and the calculation formula is: The second term in the formula is the photothermal increment, with the dimension in degrees Celsius, which represents the temperature rise caused by the irradiation energy that is not converted into electrical energy during the photovoltaic conversion process; the third term is the electrothermal increment, with the dimension in degrees Celsius, which represents the local temperature rise caused by the power dissipation of the bypass diode.

[0097] The thermal degradation term is calculated based on activation energy, Boltzmann constant, and equivalent operating temperature; the damp-heat decay term is calculated by combining relative humidity; the absolute value of the temperature change rate of equivalent operating temperature is extracted to calculate the thermal fatigue term; and the lifetime consumption rate is obtained by weighted summation of each decay term and dissipated power using the corresponding degradation sensitivity coefficient.

[0098] The formula for calculating the lifespan attrition rate is:

[0099]

[0100] in Let u be the lifetime consumption rate corresponding to unit u at time t, with the dimension of second, which characterizes the performance degradation degree of photovoltaic module and bypass diode per unit time; This represents the degradation sensitivity coefficient corresponding to the thermal degradation term, with dimensions in seconds and a range of values ​​of [value range missing]. to Calibrate every second using component aging test data; The activation energy of the encapsulation material corresponding to unit u is expressed in electron volts and ranges from 0.7 to 1.2 electron volts. This is the degradation sensitivity coefficient corresponding to the damp-heat degradation term, with dimensions in seconds and a range of values. to Calibrate per second using component damp heat aging test data; Let t be the ambient relative humidity at time t, which is a dimensionless parameter with a value range of [0,1], obtained through meteorological monitoring data; The humidity effect index is a dimensionless parameter with a value range of 2 to 5. This is the degradation sensitivity coefficient corresponding to the thermal fatigue term, with dimensions in degrees Celsius per second, and a value range of [value missing]. to Calibration is achieved per second and per degree Celsius using component thermal cycling test data. The equivalent operating temperature is the rate of change over time, measured in degrees Celsius per second, and is calculated using the difference method, which is the temperature difference between the current moment and the previous moment divided by the time step. This is the degradation sensitivity coefficient corresponding to the electrical stress degradation term, with dimensions in seconds and watts, and a value range of [value missing]. to The watts per second are calibrated using bypass diode aging test data. The first term in the formula is the thermal degradation term, calculated using the Arrhenius equation, characterizing material degradation caused by long-term high-temperature environments; the second term is the hygrothermal degradation term, characterizing the aging of the packaging material caused by the synergistic effect of high temperature and high humidity environments; the third term is the thermal fatigue term, characterizing material fatigue damage caused by temperature cycling; and the fourth term is the electrical stress degradation term, characterizing the performance degradation caused by the conduction losses of the bypass diode. All four terms are expressed in units of one second, satisfying the dimensional consistency requirement.

[0101] The cumulative lifespan consumption is obtained by integrating the lifespan consumption rate, taking the negative and performing an exponential operation to obtain the remaining performance factor, and multiplying the remaining performance factor by the ash accumulation state power to obtain the actual aging power.

[0102] The formula for calculating cumulative lifespan consumption is:

[0103]

[0104] in The cumulative lifetime consumption of unit u from initial time 0 to time t is a dimensionless parameter. The variable is the time-integral variable, with units in seconds. The integration operation uses the trapezoidal integration method, accumulating the lifetime consumption rate at each time step according to the system's calculation step size, starting from the initial time. At that time, the initial value of the cumulative lifespan consumption is 0.

[0105] The formula for calculating the residual performance factor is:

[0106]

[0107] in Let be the residual performance factor corresponding to unit u at time t, a dimensionless parameter with a value range of [0,1]. It represents the proportion of performance remaining after the component's cumulative lifetime has elapsed. The independent variable of the exponential function is a dimensionless parameter, satisfying the independent variable constraints of a transcendental function. When the cumulative lifetime has elapsed... When the value is greater than 10, the remaining performance factor is set to 0 to avoid numerical overflow.

[0108] The formula for calculating the actual power consumption during aging is:

[0109]

[0110] in Let be the actual aging power of unit u at time t, in watts, taking into account both power loss due to dust accumulation and performance degradation due to material aging.

[0111] There is a cyclic dependency between equivalent operating temperature, lifetime consumption rate, and actual aging power. A decoupling iterative method is used to address this dependency, and the steps are as follows:

[0112] The first step is to use the equivalent operating temperature of the previous moment as the initial value to calculate the ash accumulation state power and dissipation power at the current moment.

[0113] The second step is to calculate the iterative value of the equivalent operating temperature at the current moment based on the initial temperature and dissipated power.

[0114] The third step is to recalculate the power, dissipation power and equivalent operating temperature in the ash accumulation state based on the iterative equivalent operating temperature.

[0115] The fourth step is to determine whether the absolute value of the equivalent working temperature difference between two adjacent iterations is less than the convergence threshold of 0.1 degrees Celsius. If it is less, the iteration is stopped and the final result is output.

[0116] Fifth step: If the difference is greater than the convergence threshold, repeat steps two through four until the convergence condition is met or the maximum number of iterations of 20 is reached.

[0117] The total system power is obtained by summing the actual aging power of each unit, calculating the marginal economic value by combining it with the acquired power load data, and measuring the spatial segment revenue loss by combining the clean state power. First, the actual aging power corresponding to all spatial segment economic units is summed to obtain the total system power.

[0118] The formula for calculating the total system power is:

[0119]

[0120] in Let be the total system power of the photovoltaic system at time t, in watts; U is the set of all spatially segmented economic units within the photovoltaic system; To sum the actual aging power of all cells in set U, the power data of all cells are clock-synchronized before summing to ensure that the timestamps are perfectly aligned.

[0121] Using the alternative electricity purchase price, electricity load data, grid connection price, aggregated service price, and measurable service volume, a comprehensive revenue change rate function is constructed. The comprehensive revenue change rate function is composed of the sum of the product of the alternative electricity purchase price and the smaller of the total system power and electricity load data, the product of the grid connection price and the change rate of the actual surplus electricity settled on the grid, and the product of the aggregated service price and the change rate of the measurable service volume.

[0122] The formula for calculating the rate of change function of comprehensive returns is:

[0123]

[0124] in Let t be the rate of change of the overall revenue of the photovoltaic system at time t, in yuan per second, representing the overall revenue generated by the photovoltaic system per unit time. The alternative electricity purchase price at time t is expressed in yuan per kilowatt-hour, which is the price paid by the user to the public power grid, obtained from the electricity price documents published by the power grid company. The user's electricity load data at time t is in watts, which is the real-time power consumption of the user side, collected in real time by the user's smart meter. The smaller value between the total system power and the electrical load corresponds to the self-consumption photovoltaic power. The conversion factor from watts to kilowatts; The feed-in tariff at time t is expressed in yuan per kilowatt-hour, which is the settlement tariff for surplus photovoltaic power fed into the grid. This tariff is obtained from the tariff documents published by the power grid company. Let be the rate of change of the actual surplus electricity settled at time t, in kilowatt-hours per second, i.e., the real-time power of surplus electricity sold to the grid. The calculation formula is: During periods of power grid rationing, the value is 0. The aggregated service price at time t is expressed in yuan per kilowatt-hour, which is the settlement price for the photovoltaic system participating in aggregated services such as virtual power plants and demand response. This price is obtained from data released by the electricity trading market. The rate of change of measurable service power at time t, in kilowatt-hours per second, is the real-time power participating in the aggregation service, obtained through instruction data issued by the aggregation service platform.

[0125] The marginal economic value is derived by calculating the partial derivative of the rate of change of comprehensive revenue function with respect to the total system power. The formula for calculating marginal economic value is:

[0126]

[0127] in Let be the marginal economic value of the photovoltaic system at time t, expressed in yuan per kilowatt-hour, representing the change in overall revenue resulting from a change in unit photovoltaic power. The partial derivative is calculated using a piecewise function: when... hour, ;when hour, ,in This represents the proportion of serviced electricity to surplus electricity, a dimensionless parameter with a value range of [0,1], determined based on historical operational data of the system participating in aggregated services or as stipulated in power trading contracts. When the total system power... When the marginal economic value is 0, the alternative electricity purchase price is taken as the marginal economic value. The formula includes a 3600-fold time unit conversion, converting yuan per watt-second to yuan per kilowatt-hour.

[0128] The difference between the clean state power and the actual aging power is multiplied by the marginal economic value and then integrated over time to obtain the spatial segmented revenue loss.

[0129] The formula for calculating the spatial segmentation revenue loss is as follows:

[0130]

[0131] in The spatial segmented revenue loss corresponding to unit u within the annual time domain y is expressed in yuan. The power loss of unit u at time t due to dust accumulation and aging is expressed in watts. dt is the unit conversion factor from watt-hours to kilowatt-hours; dt is the time integral infinitesimal element, in hours. The integration operation is completed within the annual time domain y, using the rectangular integration method. The revenue loss of each time step is accumulated according to the system calculation step size to obtain the annual cumulative spatial segmented revenue loss. During the integration process, it is ensured that the marginal economic value and the timestamp of the power data are completely aligned.

[0132] The failure rate is determined based on the lifespan consumption rate and dynamic deposition load, and the segmented operation and maintenance and risk costs are calculated. First, the linear summation terms of cumulative lifespan consumption, average thermal exposure, average wet exposure, and dynamic deposition load are exponentially calculated and multiplied by the initial baseline failure rate to obtain the failure rate of various components.

[0133] The formulas for calculating the failure rate of various components are as follows:

[0134]

[0135] in Let be the failure rate of the k-th type of component corresponding to unit u at time t, in seconds, representing the probability of failure of the component per unit time; k is the component category number, including four categories: photovoltaic cells, bypass diodes, encapsulation materials, and junction boxes; The initial baseline failure rate for the k-th type of component is expressed in seconds and can be obtained from the component's factory reliability data or industry-standard failure rate manuals. The failure sensitivity coefficient is the cumulative lifespan consumption, which is a dimensionless parameter with a value range of 0.1 to 10. The average heat exposure of unit u during the statistical period is expressed in degrees Celsius. The statistical period is a calendar day. The average equivalent working temperature from 0:00 to 24:00 each day is calculated as the average heat exposure for that day. The reference temperature is 25 degrees Celsius. is the failure sensitivity coefficient corresponding to thermal exposure, which is a dimensionless parameter with a value range of 0.01 to 1; Let u be the average wet exposure of unit u within the statistical period. Let u be a dimensionless parameter with a value range of [0,1]. The statistical period is a natural day. The average environmental relative humidity from 0:00 to 24:00 each day is calculated as the average wet exposure of that day. is the failure sensitivity coefficient corresponding to wet exposure, which is a dimensionless parameter with a value range of 0.01 to 1; For reference, the deposition load per unit area is taken as 0.1 kg per square meter; Let be the failure sensitivity coefficient corresponding to the dynamic deposition load, a dimensionless parameter ranging from 0.01 to 1. All terms within the exponential function are dimensionless parameters, satisfying the independent variable constraints of a transcendental function.

[0136] The formula for calculating the reliability of the k-th type of component at time t is:

[0137]

[0138] in Let be the reliability of the k-th type of component at time t, and be a dimensionless parameter with a value range of [0,1], representing the probability that the component has not failed from the initial time to time t.

[0139] Multiply the cost of a single replacement of a component by the failure rate and the reliability of the component, integrate the results, and sum them to obtain the annual replacement cost.

[0140] The formula for calculating annual replacement costs is:

[0141]

[0142] in The annual replacement cost within the annual time domain y is expressed in yuan; K is the set of all component categories. Let dt be the cost of a single replacement of the k-th type of component corresponding to unit u at time t, in yuan per second, including component procurement costs and disassembly / reassembly labor costs, converted to a unit time cost based on the annual replacement cycle; dt is the time integral element, in seconds. The integration operation is completed within the annual time domain y, using the trapezoidal integration method, integrating the annual replacement costs of each type of component and summing the results to obtain the annual replacement cost of the entire system.

[0143] The labor cost is multiplied by the length of the work path, the water cost by the amount of water used for cleaning, the rate of working at height by the area of ​​temporary reinforcement, and the safety protection cost by the area of ​​safety protection. These four factors are then added together to convert the cost per unit time. The cost is then allocated according to the proportion of dynamic deposition load to the total system load and integrated to obtain the annual operation and maintenance cost.

[0144] The formula for calculating annual operation and maintenance costs is:

[0145]

[0146] in The annual operation and maintenance cost within the annual time domain y is expressed in yuan. The operation and maintenance cycle is measured in seconds, which is the time interval between two operation and maintenance tasks. The unit price for labor at time t is expressed in yuan per meter. The work path length corresponding to unit u is in meters. It refers to the shortest feasible passage path length from the rooftop work safety entrance to the unit u area, which is determined based on actual measurements of the rooftop building layout and component installation location. The unit price of water at time t is expressed in yuan per cubic meter. Let be the cleaning water consumption for unit u at time t, in cubic meters. The calculation formula is: ,in The water consumption for cleaning per unit area is expressed in cubic meters per square meter, and is determined based on local water quality conditions and the degree of dust accumulation in the unit. The rate for working at height at time t is expressed in yuan per square meter. The temporary reinforcement area corresponding to unit u is in square meters. It refers to the area of ​​the roof area that needs to be temporarily reinforced to meet the load-bearing safety requirements during high-altitude operations. It is determined based on the roof structure design load and the total weight of the workers and equipment. The unit price for safety protection at time t is expressed in yuan per square meter. The safety protection area corresponding to unit u is in square meters, which refers to the area where safety facilities such as edge protection and fall protection nets need to be set up during operation. The dynamic deposition load of unit u represents the proportion of the total deposition load of the system. This is a dimensionless parameter used to allocate the overall system maintenance cost to each unit based on the degree of ash accumulation. dt is the time integral infinitesimal element, measured in seconds. When the total deposition load of the system... When the value is 0, the allocation ratio is calculated based on the area proportion of each unit; when the dynamic deposition load of unit u is 0... When the value is 0, the allocation ratio is set to 0. The integration operation is completed within the annual time domain y, using the rectangular integration method to obtain the cumulative annual operation and maintenance cost.

[0147] The cost of critical failure risk is calculated based on the asset exposure value and the critical failure intensity.

[0148] The formula for calculating the cost of critical failure risk is as follows:

[0149]

[0150] in The cost of critical failure risk within the annual time domain y is expressed in yuan. The asset exposure value corresponding to unit u within the annual time domain y is expressed in yuan. It represents the amount of asset loss caused when a critical failure event occurs, including component damage, building fire loss, personal injury compensation, etc. It is determined through asset valuation and risk scenario analysis. For a moment The critical failure intensity corresponding to unit u, measured in seconds, represents the probability of a failure event that could lead to serious consequences such as fire or component damage. This intensity is obtained through industry risk databases and statistical analysis of field failure cases. The annual critical failure risk cost of the entire system is obtained by summing the critical failure risk costs of each unit.

[0151] The segmented maintenance and risk costs are formed by summing up the annual replacement cost, annual operation and maintenance cost, and critical failure risk cost.

[0152] The formula for calculating annual segmented operation and maintenance and risk costs is as follows:

[0153]

[0154] in This represents the segmented operation and maintenance and risk costs within the annual time domain y, expressed in yuan. During the aggregation process, it is ensured that the time periods and accounting boundaries of all cost items are completely consistent. Costs are allocated by unit dimension to obtain the annual operation and maintenance and risk costs corresponding to each unit.

[0155] The discount factor is obtained, and the costs and spatial segmented revenue losses are discounted and summarized to output a comprehensive economic indicator for the entire cycle and segmented economic consumption values. First, the discount factor is derived by performing a historical cumulative multiplication calculation based on the inflation rate and nominal cost of capital.

[0156] The formula for calculating the discount factor is:

[0157]

[0158] in Let y be the discount factor corresponding to the yth accounting year, which is a dimensionless parameter; For the first The annual inflation rate is a dimensionless parameter, obtained from historical data or future forecast data released by the national statistical department. For the first The nominal cost of capital for each year is a dimensionless parameter, determined through project financing schemes or industry benchmark rates of return. For the cumulative product operation from year 1 to year y, when the initial year y=0, the discount factor is... Take 1.

[0159] The life cycle cost is obtained by multiplying the sum of all costs in capital expenditures, decommissioning costs, and segmented operation and maintenance and risk costs by a discount factor, then summing them up, and subtracting the discounted amount of the residual value at the end of the period. The formula for calculating life cycle cost is:

[0160]

[0161] in The total life-cycle cost of the photovoltaic system is expressed in yuan; T represents the evaluation lifespan in years, which is the evaluation period for the entire life cycle of the photovoltaic system, ranging from 20 to 30 years. The capital expenditure for year y is expressed in yuan and includes initial investment and subsequent expansion and renovation expenditures. The decommissioning and disposal costs for the yth year are expressed in yuan. To evaluate the residual value at the end of the life (time T), the unit is yuan, based on the residual value rate of the initial investment (denoted as...). The residual rate is calculated using a dimensionless parameter, and the value range is from 0.05 to 0.2. This is the discount factor corresponding to the end of life, time T.

[0162] The net present value (NPV) is calculated by subtracting all operating and risk costs from the total annual revenue, multiplying by a discount factor, summing the results, subtracting initial capital expenditures, and adding the discounted amount of the difference between the ending residual value and the final decommissioning disposal cost. The formula for NPV is:

[0163]

[0164] in The net present value of the photovoltaic system over its entire life cycle is expressed in yuan. Let y be the total annual revenue for the y-th year, expressed in yuan, obtained by integrating the comprehensive revenue change rate function over the annual time domain. Capital expenditure at the initial moment, in yuan; The cost of decommissioning at time T, the end of the product's lifespan, is expressed in yuan.

[0165] The lifecycle cost is calculated by dividing the lifecycle cost by the sum of the products of effective power generation and the discount factor.

[0166] The formula for calculating the cost per kilowatt-hour over a lifetime is:

[0167]

[0168] in The cost per kilowatt-hour (kWh) of a photovoltaic system is expressed in yuan per kilowatt-hour. The effective power generation in the y-th year is expressed in kilowatt-hours, which is the total actual power output of the photovoltaic system throughout the year. It is obtained by integrating the power of the entire system over the annual time domain.

[0169] The segmented economic consumption value is obtained by multiplying the spatial segmentation revenue loss of a single spatial segmented economic unit by the sum of the annual operation and maintenance cost, annual replacement cost and key failure risk cost allocated to that unit, multiplied by the discount factor, and then subtracting the discounted residual value of the unit at the end of the period.

[0170] The formula for calculating segmented economic consumption value is:

[0171]

[0172] in This represents the segmented economic consumption value corresponding to unit u, in yuan. , , These are the annual maintenance cost, annual replacement cost, and critical failure risk cost allocated to unit u in the y-th year, respectively, in yuan, and are allocated according to the unit area ratio and the degree of dust accumulation. This is the residual value at the end of the lifespan, T, corresponding to unit u, expressed in yuan, calculated based on the ratio of unit area to the total system area.

[0173] The system outputs comprehensive economic indicators and segmented economic consumption values ​​for the entire lifecycle. The comprehensive economic indicators include lifecycle cost (LCC), net present value (NPV), and levelized cost of electricity (LCOE). The system stores the comprehensive economic indicators and the corresponding segmented economic consumption values ​​for each unit in a two-dimensional format of year-unit. The output format is structured time-series data. It also outputs detailed data on annual dust accumulation loss, aging degradation, and operation and maintenance costs for each unit, completing the economic assessment of the photovoltaic equipment's entire lifecycle.

[0174] The overall timing rules for system execution are as follows:

[0175] The system's basic calculation step is set to 1 hour, and the sampling period for meteorological data, irradiance data, and load data is consistent with the calculation step. At 0:00 every day, the system performs a summary calculation of the day's data, updating the cumulative power loss, revenue loss, and lifespan consumption for the day. At the end of each month, the system performs a monthly cost accounting, updating the monthly operation and maintenance and risk costs. At the end of each year, the system performs an annual full-cycle economic indicator update and outputs an annual assessment report. When events such as manual cleaning, component replacement, or electricity price adjustments are triggered, a full-process calculation is immediately performed, updating the relevant parameters and assessment results.

[0176] The preprocessing rules for the input data are as follows:

[0177] All input data are clocked using the NTP network time protocol, with a time synchronization error not exceeding 10% of the calculation step size. Missing data is filled using linear interpolation. If more than 3 consecutive time steps are missing, the historical average value of the same period is used for filling. Abnormal data is filtered using the 3σ criterion, and data exceeding 3 times the standard deviation of the mean is replaced with the average value of the adjacent time steps.

[0178] The embodiments of this example have been described above. However, this example is not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms based on the guidance of this example, and all of them are within the protection scope of this example.

Claims

1. A life-cycle economic evaluation system for rural photovoltaic equipment, applicable to photovoltaic systems including photovoltaic modules and bypass diodes, characterized in that, Configured for execution: Obtain the geometric region of the retention zone at the bottom edge of the component and the electrical protection region of the diode, find the intersection to construct a spatial segmented economic unit and calculate the retention strength; Based on meteorological data and the retention intensity, the dynamic deposition load of the unit is calculated; Based on the load, the transmittance is calculated, and combined with the preset clean state power and equivalent circuit model, the dust accumulation state power and non-uniform power loss are calculated. Based on the ambient temperature, irradiance and the dissipation power corresponding to the ash accumulation state power, the equivalent operating temperature is obtained, the lifetime consumption rate is calculated, the residual performance factor is obtained to correct the ash accumulation state power, and the actual aging power is obtained. The total system power is obtained by summing the actual aging power of each unit, the marginal economic value is calculated by combining the acquired power load data, and the spatial segment revenue loss is calculated by combining the clean state power. Based on the lifespan consumption rate and the load-determined failure rate, the segmented operation and maintenance and risk costs are calculated. Obtain the discount factor, discount and summarize the cost and the spatial segmented revenue loss, and output the full-cycle comprehensive economic indicator and segmented economic consumption value.

2. The life-cycle economic evaluation system for rural photovoltaic equipment according to claim 1, characterized in that, Obtain the geometric region of the retention zone at the bottom edge of the component and the electrical protection region of the diode, find their intersection to construct a spatially segmented economic unit, and calculate the retention strength, including: The intersection of the geometric region of the retention zone and the electrical protection region is extracted as an overlapping unit, forming the spatial segmented economic unit composed of all overlapping units, and the unit area is obtained by area integration; The surface runoff direction is obtained by subtracting the dot product of the gravity direction vector and the component plane normal vector from the gravity direction vector, multiplying it by the component plane normal vector, and then normalizing it. The retention strength is obtained by multiplying the height of the protrusion of the frame relative to the glass surface by the absolute value of the inner product of the surface runoff direction and the inner normal vector of the frame, integrating the product within the unit, and then dividing by the area of ​​the unit.

3. The life-cycle economic evaluation system for rural photovoltaic equipment according to claim 2, characterized in that, Based on meteorological data and the retention intensity, the dynamic deposition load of the unit is calculated, including: The absolute value of the inner product of rainfall, the water collection area flowing into the unit, and the surface runoff direction with the inner normal vector of the frame is multiplied together, and then added to the product of dew and the contribution of roof runoff, to obtain the bottom edge water collection volume. Multiply the mineral dust deposition efficiency by the inorganic particle concentration, add the product of the agricultural particle deposition efficiency and the agricultural particle concentration, and multiply the sum by the unit area to obtain the natural sedimentation increment. Multiply the bottom edge catchment volume by the retention intensity and the concentration of particles carried by the runoff to obtain the runoff interception increment; The removal rates corresponding to rainfall, dew migration, and manual washing are obtained and summed to obtain the comprehensive removal rate; The sediment mass change rate is obtained by adding the natural sedimentation increment to the runoff interception increment and subtracting the product of the comprehensive removal rate and the current dynamic sedimentation load. The dynamic sedimentation load is then obtained by integrating the change rate over time.

4. The life-cycle economic evaluation system for rural photovoltaic equipment according to claim 3, characterized in that, Based on the load-measured transmittance, and combined with the preset clean state power and equivalent circuit model, the dust accumulation state power and non-uniform charge loss are calculated, including: Multiply the extinction coefficient of the sediment by the dynamic deposition load and then divide by the unit area, take the negative sign and perform an exponential operation to obtain the single wavelength transmittance, and then obtain the transmittance by weighting. The actual local irradiance is obtained by multiplying the irradiance of the tilted surface of the photovoltaic module, the transmittance, and the spatial distribution coefficient formed by local dust accumulation. The equivalent circuit model is constructed using the actual local irradiance and preset photoelectric parameters to obtain the terminal voltage and terminal current; Find the extreme point where the difference between the product of the terminal voltage and the terminal current and the dissipated power reaches its maximum, and define the power corresponding to the extreme point as the power of the ash accumulation state. The difference between the power in the clean state and the power in the dusty state is calculated and integrated in the time domain to obtain the non-uniform power loss.

5. The life-cycle economic evaluation system for rural photovoltaic equipment according to claim 4, characterized in that, The equivalent operating temperature is calculated based on the ambient temperature, irradiance, and dissipation power corresponding to the ash accumulation state power. The lifespan consumption rate is calculated, and the residual performance factor is obtained to correct the ash accumulation state power, resulting in the actual aging power, including: Multiply the difference between the local photoelectric conversion efficiency and the irradiance of the tilted surface by the sum of the products of the zero-order heat dissipation coefficient and the first-order heat dissipation coefficient of the component and the wind speed to obtain the photothermal increment; divide the dissipated power by the product of the unit area and the local convective heat transfer coefficient to obtain the electrothermal increment; add the ambient temperature, the photothermal increment and the electrothermal increment to obtain the equivalent operating temperature. The thermal degradation term is calculated based on the activation energy, Boltzmann constant, and the equivalent operating temperature; the damp heat degradation term is calculated by combining relative humidity; the absolute value of the temperature change rate of the equivalent operating temperature is extracted to calculate the thermal fatigue term; and the lifetime consumption rate is obtained by weighted summation of each degradation term and the dissipated power using the corresponding degradation sensitivity coefficient. The cumulative lifespan consumption is obtained by integrating the lifespan consumption rate, taking the negative and performing an exponential operation to obtain the remaining performance factor, and multiplying the remaining performance factor by the ash accumulation state power to obtain the actual aging power.

6. The life-cycle economic evaluation system for rural photovoltaic equipment according to claim 5, characterized in that, The total system power is obtained by summing the actual aging power of each unit, calculating the marginal economic value by combining it with the acquired power load data, and measuring the spatial segmented revenue loss by combining it with the clean state power, including: The actual aging power corresponding to all the aforementioned spatial segmented economic units is summarized to obtain the total system power; A comprehensive revenue function is constructed using the alternative electricity purchase price, the electricity load data, the grid connection price, the aggregated service price, and the measurable service volume. The comprehensive revenue function is composed of the sum of the following three factors: the product of the alternative electricity purchase price and the smaller of the total system power and the electricity load data; the product of the grid connection price and the actual surplus electricity settled on the grid; and the product of the aggregated service price and the measurable service volume. Calculate the partial derivative of the comprehensive revenue function with respect to the total system power to obtain the marginal economic value; The difference between the clean state power and the actual aging power is multiplied by the marginal economic value, and then integrated over time to obtain the spatial segmented revenue loss.

7. The life-cycle economic evaluation system for rural photovoltaic equipment according to claim 6, characterized in that, Based on the lifespan consumption rate and the load-determined failure rate, the segmented operation and maintenance and risk costs are calculated, including: The failure rate of each type of component is obtained by multiplying the exponentially summed terms of the cumulative lifetime consumption, the average thermal and moisture exposure, and the dynamic deposition load by the initial baseline. Multiply the cost of a single replacement of a component by the failure rate and the reliability of the component, integrate and sum to obtain the annual replacement cost; Multiply the labor unit price by the length of the work path, the water source unit price by the amount of water used for cleaning, the rate of working at height by the area of ​​temporary reinforcement, and the safety protection unit price by the area of ​​safety protection. After adding these four factors together, allocate them according to the proportion of the dynamic deposition load to the total system load and integrate them to obtain the annual operation and maintenance cost. Calculate the risk cost of critical failure based on asset exposure value and critical failure intensity; The annual replacement cost, the annual operation and maintenance cost, and the critical failure risk cost are combined to form the segmented operation and maintenance and risk cost.

8. The life-cycle economic evaluation system for rural photovoltaic equipment according to claim 7, characterized in that, Obtain the discount factor, discount and summarize the costs and spatial segmented revenue losses, and output the full-cycle comprehensive economic indicator and segmented economic consumption values, including: The discount factor is derived by performing a historical cumulative multiplication calculation based on the inflation rate and the nominal cost of capital. The life cycle cost is obtained by multiplying the sum of capital expenditures, decommissioning costs, and various costs in the segmented operation and maintenance and risk costs by the discount factor, and then subtracting the discounted amount of the residual value at the end of the period. The net present value is obtained by subtracting all operation and maintenance and risk costs from the total annual revenue, multiplying by the discount factor mentioned above, summing up, subtracting the initial capital expenditure, and adding the discounted amount of the difference between the residual value at the end of the period and the final decommissioning disposal cost. The lifetime cost is obtained by dividing the lifetime cost by the sum of the products of the effective power generation and the discount factor. The segmented economic consumption value is obtained by multiplying the spatial segment revenue loss of a single spatial segmented economic unit by the sum of the annual operation and maintenance cost, annual replacement cost and key failure risk cost allocated to the unit, multiplying by the discount factor, summing them and then subtracting the discounted residual value of the unit at the end of the period. The comprehensive economic indicator for the entire life cycle includes the life cycle cost, the net present value, and the life cycle cost per kilowatt-hour.

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