Method for evaluating electrical losses of photovoltaic array

Abstract

Provided in the embodiments of the present disclosure is a method for evaluating electrical losses in a photovoltaic array. The method comprises: on the basis of an uncovered cell surface total radiation amount, a cell surface total radiation amount in a covered region, a cell surface covered area and a total cell area, calculating a cell surface equivalent total radiation amount; on the basis of the cell surface equivalent total radiation amount and a cell covered equivalent electric current condition, calculating a cell covered electric current, and on the basis of the uncovered cell surface total radiation amount and a cell uncovered equivalent electric current condition, calculating a cell uncovered electric current; on the basis of a covered power generation amount, an uncovered power generation amount and a total covering loss condition, calculating a total covering loss; on the basis of a total covered area, a covered radiation amount, an array area and an uncovered radiation amount of a photovoltaic array, calculating a theoretical radiation loss per unit of time of the photovoltaic array; using the uncovered radiation amount within a preset time period as a weight to perform weighted calculation on a weighted radiation loss of the photovoltaic array within the preset time period; and on the basis of the total covering loss and the weighted radiation loss of the photovoltaic array, calculating the difference to calculate the electrical loss ratio of the photovoltaic array.

Description

A method for evaluating electrical loss of a photovoltaic array TECHNICAL FIELD

[0001] Embodiments of the present disclosure belong to the field of photovoltaic technology, and particularly relate to a method for evaluating electrical loss of a photovoltaic array. BACKGROUND

[0002] Photovoltaic power generation is an important path and industrial support for realizing China's low-carbon and green development strategy. Distributed photovoltaic power generation has become an important part of new photovoltaic power generation. In 2022, the national distributed photovoltaic project added 51.11 GW of installed capacity, an increase of 74.9% year-on-year, accounting for 58.5% of the total new photovoltaic installed capacity in the year. In the first three quarters of 2023, distributed photovoltaic power generation added 67.14 GW, accounting for 52.1% of the total new photovoltaic installed capacity.

[0003] Distributed photovoltaic power stations are located near load centers, with high population density and active economy. Various buildings or trees, towers, etc. with certain heights are densely distributed. Distributed photovoltaic power stations are usually built on building roofs, and staircases, heating and ventilation equipment, exhaust ducts, billboards, etc. on building roofs are also distributed. When the surrounding opaque objects exceed the installation surface of the photovoltaic module, shadows may be generated, which will have a certain impact on the power generation of the photovoltaic power station. In fact, the most important factor for abnormal power generation of distributed photovoltaic power stations is also the serious shadow blocking of the photovoltaic array.

[0004] Current technologies can model the height information and mutual position relationship of various objects in the photovoltaic site area, and simulate the shadow blocking on the surface of the photovoltaic array at any time according to the solar trajectory of the site area. The loss caused by shadow blocking usually includes the loss of reduced radiation in the blocked area, and also includes the additional electrical loss of the unblocked area due to the electrical connection characteristics of the photovoltaic cells and photovoltaic modules.

[0005] Some of the current design software only calculates the radiation loss caused by the reduced radiation of the blocked area of the photovoltaic array, but lacks technical means to estimate the electrical loss of the photovoltaic array after blocking.

[0006] Therefore, how to solve the above problems has become a technical problem to be solved by those skilled in the art. SUMMARY

[0007] Embodiments of the present disclosure aim to at least solve one of the technical problems existing in the prior art, and provide a method for evaluating electrical loss of a photovoltaic array.

[0008] In one aspect of embodiments of the present disclosure, a method for evaluating electrical loss of a photovoltaic array is provided, comprising:

[0009] The battery surface equivalent total radiation is calculated according to the total radiation of the unshaded battery surface, the total radiation of the shaded area battery surface, the shaded area of the battery surface and the total area of the battery.

[0010] The battery shading current is calculated according to the battery surface equivalent total radiation and the battery shading equivalent current condition, and the battery unshading current is calculated according to the total radiation of the unshaded battery surface and the battery unshading equivalent current condition; wherein, the battery shading voltage is calculated based on the battery shading current, and the battery unshading voltage is calculated based on the battery unshading current; the shading power and the unshading power of the photovoltaic array are calculated based on the battery shading current, the battery unshading current, the battery shading voltage and the battery unshading voltage;

[0011] The shading power and the unshading power in a unit time are calculated by summing the products of the shading power and the unshading power and the time step; the unit time includes at least one time step.

[0012] The shading total loss is calculated based on the shading power, the unshading power and the shading total loss condition.

[0013] The theoretical radiation loss of the photovoltaic array in a unit time is calculated according to the total shading area of the photovoltaic array, the shading radiation, the array area and the unshading radiation.

[0014] The weighted radiation loss proportion of the photovoltaic array in a preset period is calculated by weighting the unshading radiation in the preset period; the preset period includes at least one unit time.

[0015] The electrical loss proportion of the photovoltaic array is calculated by subtracting the weighted radiation loss from the shading total loss of the photovoltaic array.

[0016] Optionally, the battery surface equivalent total radiation is calculated according to the total radiation of the unshaded battery surface, the total radiation of the shaded area battery surface, the shaded area of the battery surface and the total area of the battery, including:

[0017] The battery surface equivalent total radiation calculation satisfies the condition formula: , wherein The total radiation of the unshaded battery surface is G0, The total radiation of the shaded area battery surface is G1, The shaded area of the battery surface is A1, The total area of the battery is A0.

[0018] Optionally, the battery shading current is calculated according to the battery surface equivalent total radiation and the battery shading equivalent current condition, and the battery unshading current is calculated according to the total radiation of the unshaded battery surface and the battery unshading equivalent current condition, including:

[0019] The battery shading equivalent current condition satisfies the condition formula: wherein is the short-circuit current temperature coefficient, is the battery temperature under the condition, is the total radiation under the condition, is the battery operating temperature,

[0020] is the maximum power point current of the photovoltaic array;

[0021] Optionally, the calculating the battery shaded voltage based on the battery shaded current and the calculating the battery unshaded voltage based on the battery unshaded current comprises:

[0022] The calculating the battery shaded voltage satisfies the condition formula: is the battery series resistance,

[0023] The calculating the battery unshaded voltage satisfies the condition formula:

[0024] Optionally, the calculating the shaded power and the unshaded power of the photovoltaic array based on the battery shaded current, the battery unshaded current, the battery shaded voltage and the battery unshaded voltage comprises:

[0025] The calculating the shaded power of the photovoltaic array satisfies the condition formula: is the photovoltaic array shaded current,

[0026] The calculating the unshaded power of the photovoltaic array satisfies the condition formula: is the photovoltaic array unshaded current,

[0027] Optionally, the calculating the photovoltaic array shaded current and the photovoltaic array shaded voltage comprises:

[0028] The calculating the battery string shaded current based on the battery shaded current and the battery string shaded current calculation condition satisfies the condition formula:

[0029] The calculating the battery string shaded voltage based on the battery shaded voltage and the battery string shaded voltage calculation condition satisfies the condition formula: ​​​​​​​​​​​​​the number of cells in a battery string;

[0030] The component shading current is calculated based on a battery string shading current and a component shading current calculation condition, the component shading current calculation condition satisfying a condition formula: , the number of cells in a battery string;

[0031] The component shading voltage is calculated based on a battery string shading voltage and a component shading voltage calculation condition, the component shading voltage calculation condition satisfying a condition formula: .

[0032] The component string shading current is calculated based on a component shading current and a component string shading current calculation condition, the component string shading current calculation condition satisfying a condition formula: , the number of battery strings in a component;

[0033] The component string shading voltage is calculated based on a component shading voltage and a component string shading voltage calculation condition, the component string shading voltage calculation condition satisfying a condition formula: .

[0034] The photovoltaic array shading current is calculated based on a component string shading current and a photovoltaic array shading current calculation condition, the photovoltaic array shading current calculation condition satisfying a condition formula: , the number of component strings in a photovoltaic array;

[0035] The photovoltaic array shading voltage is calculated based on a component string shading voltage and a photovoltaic array shading voltage calculation condition, the photovoltaic array shading voltage calculation condition satisfying a condition formula: .

[0036] The calculation of the shading power of the photovoltaic array satisfies a condition formula: .

[0037] Optionally, the calculation of the total shading loss based on the shading power, the unshading power and a total shading loss calculation condition comprises:

[0038] The battery string unshading current is calculated based on a battery unshading current and a battery string unshading current calculation condition, the battery string unshading current calculation condition satisfying a condition formula: .

[0039] The battery string unshading voltage is calculated based on a battery unshading voltage and a battery string unshading voltage calculation condition, the battery string unshading voltage calculation condition satisfying a condition formula: , the number of cells in a battery string;

[0040] The unshaded component current is calculated based on the unshaded current calculation conditions of the battery string and the unshaded component current. The unshaded component current calculation conditions meet the conditional formula: , is the number of batteries in a battery string;

[0041] The unshaded voltage of the module is calculated based on the unshaded voltage of the battery string and the unshaded voltage calculation conditions of the module. The unshaded voltage calculation conditions of the module meet the conditional formula:

[0042] The unshaded current of the component string is calculated based on the unshaded current of the component and the calculation conditions of the unshaded current of the component string. The calculation conditions of the unshaded current of the component string meet the conditional formula: , The number of battery strings in a module;

[0043] The unshaded voltage of the component string is calculated based on the unshaded voltage of the component and the calculation conditions of the unshaded voltage of the component string. The calculation conditions of the unshaded voltage of the component string meet the conditional formula:

[0044] The unshaded current of the PV array is calculated based on the unshaded current of the component string and the unshaded current calculation conditions of the PV array. The unshaded current calculation conditions of the PV array meet the following conditional formula: , is the number of component strings in a PV array;

[0045] The unshaded voltage of the PV array is calculated based on the unshaded voltage of the component string and the unshaded voltage calculation conditions of the PV array. The unshaded voltage calculation conditions of the PV array meet the conditional formula: .

[0046] The calculation of the unobstructed power of the photovoltaic array satisfies the following condition: .

[0047] Optionally, the calculation of the blocked power generation and the unblocked power generation per unit time based on the sum of the products of the blocked power and the unblocked power and the time step includes:

[0048] The calculation of the blocked power generation satisfies the following condition: ,in, is the sum of the product of the shading power and the time step per unit time, is the number of units of time within the preset period, is the number of intervals per unit time;

[0049] The calculation of unobstructed power generation satisfies the following condition: ,in, It is the sum of the products of the unobstructed power and the time step per unit time.

[0050] Optionally, the calculation of the total occlusion loss satisfies the condition: .

[0051] Optionally, the calculation of the theoretical radiation loss per unit time of the photovoltaic array satisfies the conditional formula: , is the total area blocked by the photovoltaic array surface, is the amount of radiation after the photovoltaic array is blocked, is the photovoltaic array area and is the unblocked radiation of the photovoltaic array;

[0052] The calculation of the weighted radiation loss ratio of the photovoltaic array satisfies the following condition: , Unit time The slope radiation data when it is not blocked, It is the time interval statistics of unit time within the preset period.

[0053] The beneficial effects of the embodiments of the present disclosure include:

[0054] The present disclosure proposes a method for quickly evaluating the electrical loss of a photovoltaic array under shadow in a distributed photovoltaic power generation simulation tool. Through the method disclosed in the present disclosure, the distributed photovoltaic power generation simulation tool can set typical days according to the geographical location and shadow conditions, simulate the shadow shadow conditions of a single photovoltaic cell, battery string, component, component string and photovoltaic array throughout the year on each typical day, and obtain the hourly radiation of the unshaded and shaded areas. The current and voltage calculation method under incomplete shadowing of photovoltaic cells is simplified, and the current and voltage values ​​of battery strings, components, component strings and photovoltaic arrays throughout the year are simulated and calculated hourly on typical days. The power generation of the photovoltaic array under shadowed and unshaded conditions on typical days and throughout the year is calculated, and the total shadow loss of the photovoltaic array throughout the year is calculated. The radiation loss is calculated by the hourly array shadow area, shadowed and unshaded radiation, and the radiation loss is weighted to calculate the radiation loss throughout the year. The electrical loss for the whole year is calculated by the difference between the total shadow loss and the radiation loss for the whole year. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] FIG1 is a flow chart of a method for evaluating electrical loss of a photovoltaic array according to another embodiment of the present disclosure. Modes for Carrying Out the Invention

[0056] In order to enable those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0057] The embodiments of the present application will be further described in details with reference to the drawings and examples. The detailed description and drawings of the following examples are intended to illustrate the principles of the present application, but not to limit the scope of the present application, i.e. the present application is not limited to the described examples. In the description of the present application, it is necessary to explain that, unless otherwise specified, the meaning of "a plurality of" is more than two; the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship only for the purpose of facilitating the description of the present application and simplifying the description, and are not intended to indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0058] In the description of the present application, it is also necessary to explain that, unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0059] As shown in FIG. 1, a method for evaluating electrical loss of a photovoltaic array includes:

[0060] S101, calculating the equivalent total radiation of the cell surface according to the total radiation of the unshaded cell surface, the total radiation of the shaded area of the cell surface, the shaded area of the cell surface and the total area of the cell.

[0061] S102, calculating the shaded current of the cell according to the equivalent total radiation of the cell surface and the equivalent current condition of the cell shading, and calculating the unshaded current of the cell according to the total radiation of the unshaded cell surface and the equivalent current condition of the cell unshading. Wherein, the shaded voltage of the cell is calculated based on the shaded current of the cell, and the unshaded voltage of the cell is calculated based on the unshaded current of the cell. The shaded power and the unshaded power of the photovoltaic array are calculated based on the shaded current of the cell, the unshaded current of the cell, the shaded voltage of the cell and the unshaded voltage of the cell.

[0062] S103, calculating the shaded power generation and the unshaded power generation per unit time based on the sum of the product of the shaded power and the unshaded power and the time step, the unit time including at least one time step.

[0063] S104, calculating the total loss of shading based on the shaded power generation, the unshaded power generation and the total loss condition of shading.

[0064] S105, calculating the theoretical radiation loss of the photovoltaic array per unit time according to the total area of the photovoltaic array, the shading radiation, the array area, and the unshaded radiation.

[0065] S106, calculating the weighted radiation loss proportion of the photovoltaic array in a preset period by weighting the unshaded radiation in the preset period; the preset period includes at least one unit time.

[0066] S107, calculating the electrical loss proportion of the photovoltaic array by subtracting the weighted radiation loss from the total loss of the photovoltaic array.

[0067] Specifically, 1, selecting a typical day to obtain the hourly radiation of the typical day in the site area. It can be understood that the unit time includes but is not limited to the typical day, and the time step includes but is not limited to the hour.

[0068] 2, modeling of the distributed photovoltaic power station and simulation of the shadow of the typical day.

[0069] 3, calculating the inclined radiation of the photovoltaic array. Specifically, the inclined radiation of the photovoltaic array is calculated according to the hourly radiation of the typical day in the site area.

[0070] 4, calculating the current, voltage, and power of the photovoltaic array per hour under the shading and unshading of the typical day.

[0071] 5, calculating the annual power generation of the photovoltaic array under the shading and unshading. It can be understood that the preset period includes but is not limited to the year.

[0072] 6, calculating the total loss and radiation loss of the annual power generation of the photovoltaic array.

[0073] 7, calculating the electrical loss of the annual power generation of the photovoltaic array.

[0074] One specific example provided by the present disclosure includes:

[0075] 1, determining the typical day and the typical day interval period of the project, and obtaining the hourly unshaded radiation of the typical day in the typical year in the project site area. It can be understood that the unit time includes but is not limited to the day.

[0076] The selection of the typical day and the typical day interval period can be determined in combination with the latitude and shading condition of the site area. The number of typical days can be reduced by increasing the typical day interval period, and the hourly data of each day in the interval period in the following calculation steps are consistent with the data of the typical day described in the present disclosure.

[0077] 2. Build a model of the distributed photovoltaic power station and related opaque objects in the computer system, and simulate the calculated photovoltaic array surface typical day hourly shading distribution according to the solar trajectory of the site area. The time step can be reduced or enlarged as needed to achieve minute-level or hour-level simulation, and the time step does not affect the implementation of other algorithms of the method.

[0078] Obtain the shading of each component and each battery of the photovoltaic array at each time of the typical day through shadow simulation, obtain the total shading area of the photovoltaic array at each time , and the shading area of each battery in each component string and each battery , obtain the shading radiation and unshading radiation of the photovoltaic array and the battery, and the radiation of the shading area includes the total horizontal radiation, direct radiation and scattered radiation.

[0079] 3. According to the unshading radiation, shading area radiation and installation inclination and azimuth angle of the photovoltaic array obtained in steps 1 and 2, calculate the total radiation of the photovoltaic array and the battery surface at each time , the total radiation of the shading area battery surface , the post-shading radiation of the photovoltaic array , and the unshading radiation of the photovoltaic array .

[0080] 4. Calculate the current and voltage of each battery, battery string, component, component string and photovoltaic array of the typical day, and calculate the power of the photovoltaic array. This step is calculated according to the shading condition and the completely unshading condition. The specific steps are as follows:

[0081] The equivalent calculation of the current and voltage of the battery includes:

[0082] Shading condition:

[0083] According to the shading area, the equivalent calculation of the battery surface radiation, the equivalent total radiation of the battery surface :

[0084]

[0085] In the formula, is the total radiation of the battery surface without shading, is the total radiation of the battery surface in the shading area, is the shading area of the battery surface, is the total area of the battery.

[0086] The equivalent current of the battery shading: , wherein is the short-circuit current temperature coefficient, is the Battery temperature under conditions, take 25℃, For Total radiation under conditions, take 1000W / m 2 . Battery operating temperature, Maximum power point current of photovoltaic array. , Ambient temperature, Battery Rated battery operating temperature) temperature.

[0087] Battery shunt voltage , where Battery series resistance, Open circuit voltage temperature coefficient.

[0088] No shading conditions:

[0089] Battery no shading equivalent current ,

[0090] Battery no shading voltage .

[0091] The current and voltage calculation of the battery string includes:

[0092] Shading conditions:

[0093] Battery string shading current , Battery string shading voltage , The number of batteries in a battery string.

[0094] No shading conditions:

[0095] Battery string no shading current , Battery string no shading voltage , The number of batteries in a battery string.

[0096] The current and voltage calculation of the module includes:

[0097] Shading conditions:

[0098] Module shading current , Module shading voltage , The number of batteries in a battery string.

[0099] No shading conditions:

[0100] Module no shading current , , Number of cells in a string.

[0101] Current and voltage calculations for a string of modules include:

[0102] Shaded conditions:

[0103] String shaded current ,

[0104] String shaded voltage , Number of modules in a string.

[0105] Unshaded conditions:

[0106] String unshaded current ,

[0107] String unshaded voltage , Number of modules in a string.

[0108] Current and voltage calculations for a photovoltaic array include:

[0109] Shaded conditions:

[0110] Array shaded current , array shaded voltage , array shaded power , Number of strings in a photovoltaic array.

[0111] Unshaded conditions:

[0112] Array unshaded current , array unshaded voltage , array unshaded power , Number of strings in a photovoltaic array.

[0113] Further, annual photovoltaic array energy production under shaded and unshaded conditions is calculated from typical day hourly power. Annual photovoltaic array energy production under shaded and unshaded conditions and are calculated by summing the product of typical day hourly power , and time step , over the typical day interval. Annual photovoltaic array energy production under shaded and unshaded conditions and are calculated by multiplying the typical day energy production by the typical day interval period. ​

[0114] Specifically, , is the typical day hourly power without shading, is the first time step in the day, wherein, takes value 1, is the number of hours in a day, the number of hours in a day is 24. It can be understood that the unit time includes but is not limited to day (including typical day), and the time step includes but is not limited to hour. In some embodiments, the time step is 0.5h, then is 24 / 0.5=48. , is the typical day hourly power without shading, takes 1, takes 24.

[0115] The calculation of the shading power generation satisfies the condition formula: , and the calculation of the unshading power generation satisfies the condition formula: , is the number of unit times in a preset period, is the number of intervals in a unit time. Wherein, the total annual shading loss of the photovoltaic array .

[0116] According to the typical day hourly total area of the photovoltaic array surface shading , the shading radiation , the photovoltaic array area and the unshading radiation of the photovoltaic array . Calculate the typical day hourly theoretical radiation loss of the photovoltaic array , , calculate the annual weighted radiation loss ratio of the photovoltaic array , , is the unshading slope radiation data in a unit time , and is the time interval statistics of a unit time in a preset period.

[0117] Calculate the annual electrical loss ratio of the photovoltaic array , , that is, the electrical loss ratio of the photovoltaic array under the shadow shading is calculated.

[0118] The present disclosure provides a method for quickly evaluating electrical loss of a photovoltaic array under shadowing in a distributed photovoltaic power generation simulation tool. Through the method, the distributed photovoltaic power generation simulation tool can set typical days according to the geographical location and shadowing condition, simulate the shadowing condition of a single photovoltaic cell, cell string, module, module string and photovoltaic array in each typical day throughout the year, and obtain the hourly radiation in the unshaded and shaded areas. The method simplifies the current and voltage calculation method of the photovoltaic cell under incomplete shading, calculates the current and voltage values of the cell string, module, module string and photovoltaic array throughout the year through hourly simulation in the typical day, calculates the power generation of the photovoltaic array in the typical day and throughout the year under shading and unshading, and calculates the total loss of the photovoltaic array throughout the year. The radiation loss is calculated by the hourly array shading area, shading and unshaded radiation, and the annual radiation loss is calculated by weighting. The annual electrical loss is calculated by the difference between the total loss and the radiation loss.

[0119] The present disclosure can arbitrarily select a typical day, simplify the calculation of the current and voltage of the photovoltaic cell to the photovoltaic array in the typical day, and finally estimate the total loss, radiation loss and electrical loss of the photovoltaic array under dynamic shadowing in a year.

[0120] The present disclosure can be used to accurately evaluate the short-term, medium-term and long-term power generation of a distributed photovoltaic power station, and evaluate the construction feasibility of a distributed photovoltaic power station installed in a site with shadowing.

[0121] The present disclosure can be applied to the analysis of building photovoltaic available areas in any region of China.

[0122] The present disclosure provides a method for quickly evaluating electrical loss of a photovoltaic array under shadowing in a distributed photovoltaic power generation simulation tool. Through analyzing the shadow distribution and radiation on the surface of the photovoltaic array in the typical day, the calculation amount of each day throughout the year is reduced. The shadowing area on the cell is equivalent to uniform loss of radiation, the current and voltage of the cell string, module, module string and photovoltaic array under shading and unshading are quickly simulated in the typical day, and the hourly power of the photovoltaic array under shading and unshading is calculated. The annual power generation, total loss and radiation loss are quickly calculated in the typical day, and finally the electrical loss caused by the shadowing of the photovoltaic array can be calculated.

[0123] The advantages of the technical solution include:

[0124] The present disclosure provides a quick method for accurately calculating the total loss and electrical loss of a specified photovoltaic array and photovoltaic power station. The radiation of the cell shading area is converted to be equivalent, and the current and voltage calculation of the photovoltaic cell and module is simplified.

[0125] The calculation amount is greatly reduced. The typical day is used instead of daily data calculation, and the interval time of the typical day can be freely selected. The calculation amount is further reduced. The calculation amount is greatly reduced. The typical day is used instead of daily data calculation, and the interval time of the typical day can be freely selected. The calculation amount is further reduced.

[0126] Suitable for all types of batteries and components, suitable for various scales of photovoltaic strings, photovoltaic arrays.

[0127] Suitable for any area.

[0128] The method for quickly evaluating the electrical loss of a photovoltaic array under shadow shielding in the distributed photovoltaic power generation simulation tool disclosed by the present disclosure is the core of quickly calculating the current, voltage and power of the photovoltaic array under shielding and non-shielding, and calculating the total loss and electrical loss of the photovoltaic array under typical days representing the annual photovoltaic array. It is beneficial to the accurate evaluation of the influence of shielding and the accurate estimation of the power generation of the photovoltaic array, and is beneficial to the comprehensive evaluation of the feasibility of the construction of the photovoltaic power station.

[0129] In some embodiments, the typical day can be freely selected according to latitude and calculation speed.

[0130] The simplified model for calculating the current and voltage of the photovoltaic cell under the shielding condition includes: the equivalent conversion of the shielding area and the radiation loss into uniform radiation loss, and the simplified current and voltage calculation formula.

[0131] The calculation of the current, voltage and power of the photovoltaic array under the shielding condition is based on the internal logical relationship between the current and voltage of the photovoltaic cell to the photovoltaic array with electrical connection characteristics.

[0132] The present disclosure provides a computer readable storage medium having a computer program stored thereon, which can implement the above-mentioned method for evaluating the electrical loss of the photovoltaic array when executed by a processor.

[0133] The computer readable storage medium can be any tangible medium containing or storing a program, which can be electrical, magnetic, optical, electromagnetic, infrared, semiconductor system, device, equipment, and more specific examples include but are not limited to: electrical connection with one or more wires, portable computer disk, hard disk, optical fiber, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof.

[0134] The computer readable storage medium can also include a data signal propagating in the baseband or as part of a carrier wave, which carries computer readable program code, and specific examples include but are not limited to electromagnetic signals, optical signals, or any suitable combination thereof.

[0135] It is understood that the above embodiments are only exemplary for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Various modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A method for evaluating electrical losses in a photovoltaic array, characterized in that: include: Calculate the equivalent total radiation of the battery surface based on the total radiation of the unblocked battery surface, the total radiation of the battery surface in the blocked area, the blocked area of ​​the battery surface and the total area of ​​the battery; The battery shielding current is calculated based on the equivalent total radiation of the battery surface and the battery shielding equivalent current condition, and the battery unshielded current is calculated based on the unshielded total radiation of the battery surface and the battery unshielded equivalent current condition; wherein, the battery shielding voltage is calculated based on the battery shielding current, and the battery unshielded voltage is calculated based on the battery unshielded current; the shielded power and unshielded power of the photovoltaic array are calculated based on the battery shielding current, the battery unshielded current, the battery shielding voltage and the battery unshielded voltage; Calculating the blocked power generation and the unblocked power generation per unit time based on the sum of the products of the blocked power and the unblocked power and the time step; the unit time includes at least one time step; Calculating the total shading loss based on the shading power generation, the unshading power generation and the total shading loss condition; Calculate the theoretical radiation loss per unit time of the photovoltaic array based on the total shielding area of ​​the photovoltaic array, the shielding radiation, the array area and the unshielded radiation; The unobstructed radiation amount in the preset period is used as a weight to calculate the weighted radiation loss ratio of the photovoltaic array in the preset period; the preset period includes at least one unit time; The electrical loss ratio of the PV array is calculated based on the difference between the total shading loss and the weighted radiation loss of the PV array.

2. A method for evaluating electrical loss of a photovoltaic array according to claim 1, characterized in that: The calculation of the equivalent total radiation of the battery surface based on the total radiation of the unblocked battery surface, the total radiation of the battery surface in the blocked area, the blocked area of ​​the battery surface and the total area of ​​the battery includes: The calculation of the equivalent total radiation on the battery surface satisfies the following condition: , where is the total radiation on the unobstructed cell surface, is the total radiation on the surface of the battery in the shielding area, is the shielding area of ​​the battery surface, is the total battery area.

3. A method for evaluating photovoltaic array electrical loss according to claim 2, characterized in that: The calculation of the battery shielding current according to the equivalent total radiation of the battery surface and the battery shielding equivalent current condition, and the calculation of the battery unshielded current according to the unshielded total radiation of the battery surface and the battery unshielded equivalent current condition, include: The battery blocking equivalent current condition satisfies the following formula: ,in is the short-circuit current temperature coefficient, for Under the condition of battery temperature, for The total radiation under the conditions is the battery operating temperature, is the maximum power point current of the photovoltaic array; The unobstructed equivalent current condition of the battery satisfies the following formula: 。 4. A method for evaluating electrical loss of a photovoltaic array according to claim 3, characterized in that: The calculating of the battery blocking voltage based on the battery blocking current and the calculating of the battery unblocked voltage based on the battery unblocked current include: The calculation of the battery shielding voltage satisfies the conditional formula: ,in is the battery series resistance, is the open circuit voltage temperature coefficient; The calculation of the unobstructed voltage of the battery satisfies the conditional formula: 。 5. A method for evaluating electrical loss of a photovoltaic array according to claim 4, characterized in that: The calculation of the blocked power and the unblocked power of the photovoltaic array based on the blocked current of the battery, the unblocked current of the battery, the blocked voltage of the battery, and the unblocked voltage of the battery includes: The calculation of the shading power of the photovoltaic array satisfies the conditional formula: ,in, Shielding the photovoltaic array from current, Shielding voltage for photovoltaic arrays; The calculation of the unobstructed power of the photovoltaic array satisfies the conditional formula: ,in, is the unblocked current of the photovoltaic array, It is the unblocked voltage of the photovoltaic array.

6. A method for evaluating electrical loss of a photovoltaic array according to claim 5, characterized in that: The calculation of the photovoltaic array shading current and the photovoltaic array shading voltage includes: The battery string shielding current is calculated based on the battery shielding current and the battery string shielding current calculation conditions. The battery string shielding current calculation conditions meet the conditional formula: The battery string shading voltage is calculated based on the battery shading voltage and the battery string shading voltage calculation condition. The battery string shading voltage calculation condition satisfies the conditional formula: ， is the number of batteries in a battery string; The module shading current is calculated based on the battery string shading current and the module shading current calculation conditions. The module shading current calculation conditions meet the conditional formula: ， is the number of batteries in a battery string; The module shading voltage is calculated based on the battery string shading voltage and the module shading voltage calculation conditions. The module shading voltage calculation conditions meet the conditional formula: ； The component string shading current is calculated based on the component shading current and the component string shading current calculation conditions. The component string shading current calculation conditions meet the conditional formula: ， The number of battery strings in a module; The component string shading voltage is calculated based on the component shading voltage and the component string shading voltage calculation condition. The component string shading voltage calculation condition satisfies the conditional formula: ； The PV array shading current is calculated based on the component string shading current and the PV array shading current calculation conditions. The PV array shading current calculation conditions meet the following conditional formula: ， is the number of component strings in a PV array; The PV array shading voltage is calculated based on the component string shading voltage and the PV array shading voltage calculation conditions. The PV array shading voltage calculation conditions meet the following conditional formula: ； The calculation of the shading power of the photovoltaic array meets the conditional formula: 。 7. A method for evaluating photovoltaic array electrical loss according to claim 6, characterized in that: The calculating of the total shielding loss based on the shielding power generation, the unshielded power generation and the total shielding loss condition includes: The unshaded current of the battery string is calculated based on the unshaded current of the battery and the calculation conditions of the unshaded current of the battery string. The calculation conditions of the unshaded current of the battery string meet the conditional formula: ； The unshaded voltage of the battery string is calculated based on the unshaded voltage of the battery and the calculation conditions of the unshaded voltage of the battery string. The calculation conditions of the unshaded voltage of the battery string meet the conditional formula: ， is the number of batteries in a battery string; The unshaded component current is calculated based on the unshaded current calculation conditions of the battery string and the unshaded component current. The unshaded component current calculation conditions meet the conditional formula: ， is the number of batteries in a battery string; The unshaded voltage of the module is calculated based on the unshaded voltage of the battery string and the unshaded voltage calculation conditions of the module. The unshaded voltage calculation conditions of the module meet the conditional formula: ； The unshaded current of the component string is calculated based on the unshaded current of the component and the calculation conditions of the unshaded current of the component string. The calculation conditions of the unshaded current of the component string meet the conditional formula: ， The number of battery strings in a module; The unshaded voltage of the component string is calculated based on the unshaded voltage of the component and the calculation conditions of the unshaded voltage of the component string. The calculation conditions of the unshaded voltage of the component string meet the conditional formula: ； The unshaded current of the PV array is calculated based on the unshaded current of the component string and the unshaded current calculation conditions of the PV array. The unshaded current calculation conditions of the PV array meet the following conditional formula: ， is the number of component strings in a PV array; The unshaded voltage of the photovoltaic array is calculated based on the unshaded voltage of the component string and the unshaded voltage calculation conditions of the photovoltaic array. The unshaded voltage calculation conditions of the photovoltaic array meet the conditional formula: ； The calculation of the unobstructed power of the photovoltaic array satisfies the following condition: 。 8. The method for evaluating photovoltaic array electrical loss according to claim 7, characterized in that: The calculation of the blocked power generation and the unblocked power generation per unit time based on the sum of the products of the blocked power and the unblocked power and the time step includes: The calculation of the blocked power generation satisfies the following condition: ,in, is the sum of the product of the shading power and the time step per unit time, is the number of units of time within the preset period, is the number of intervals per unit time; The calculation of unobstructed power generation satisfies the following condition: ,in, It is the sum of the products of the unobstructed power and the time step per unit time.

9. The method for evaluating electrical loss of a photovoltaic array according to claim 8, wherein: The calculation of the total occlusion loss satisfies the following condition: .

10. The method for evaluating photovoltaic array electrical loss according to claim 1, characterized in that: The calculation of the theoretical radiation loss per unit time of the photovoltaic array satisfies the following condition: ， is the total area blocked by the photovoltaic array surface, is the amount of radiation after the photovoltaic array is blocked, is the photovoltaic array area and is the unblocked radiation of the photovoltaic array; The calculation of the weighted radiation loss ratio of the photovoltaic array satisfies the following condition: ， Unit time The slope radiation data when it is not blocked, It is the time interval statistics of unit time within the preset period.

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