Installed capacity optimization method and installed capacity optimization device for distributed photovoltaic grid-connected system

Abstract

The present invention provides an installed capacity optimization method and an installed capacity optimization device for a distributed photovoltaic grid-connected system, the method comprising: obtaining a daily solar radiation intensity characteristic curve corresponding to each quarter of the location of the distributed photovoltaic grid-connected system, a daily output power characteristic curve corresponding to each quarter under a variety of photovoltaic installed capacities, and a daily load power characteristic curve; obtaining the average value of the standard deviation of the daily output power characteristic curve and the daily load power characteristic curve corresponding to each quarter under each photovoltaic installed capacity, and obtaining a fluctuation degree value corresponding to each photovoltaic installed capacity; fitting data of the fluctuation degree value changing with the photovoltaic installed capacity and generating a fitting mathematical function to obtain the optimal installed capacity. The present invention combines the output power and the load power, analyzes and obtains the fluctuation degree value of the surplus power on-grid power, obtains the optimal installed capacity according to the fluctuation degree value, thereby effectively reducing the fluctuation degree of the surplus power on-grid power and improving the stability of the distribution system.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and in particular to an installed capacity optimization method and an installed capacity optimization device for a distributed photovoltaic grid-connected system. Background Art

[0002] Photovoltaic power generation is a technology that uses the photovoltaic effect of semiconductor interfaces to directly convert light energy into electrical energy. It is of great significance to alleviate energy shortages, promote energy conservation and emission reduction, and maintain the independence and cleanliness of energy supply. Distributed photovoltaic grid-connected systems refer to photovoltaic power generation facilities built near user sites, which are mostly operated in a self-generated and self-used manner on the user side, with excess electricity being connected to the grid, and are characterized by balanced regulation in the distribution system.

[0003] Since the surplus power of distributed photovoltaic power depends on the photovoltaic installed capacity and the load power consumption, if the photovoltaic installed capacity is not reasonably configured, the surplus power will fluctuate greatly. If the photovoltaic installed capacity is small, it will neither meet the load demand nor make full use of solar energy resources; if the photovoltaic installed capacity is large, the surplus power will fluctuate greatly, which will lead to power abandonment and reduce the photovoltaic power consumption rate. If it is not handled properly, it may even cause instability in the distribution system. Summary of the invention

[0004] In order to solve the above technical problems, a first aspect of the present invention provides a method for optimizing the installed capacity of a distributed photovoltaic grid-connected system.

[0005] A second aspect of the present invention provides an installed capacity optimization device for a distributed photovoltaic grid-connected system.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention proposes a method for optimizing the installed capacity of a distributed photovoltaic grid-connected system, comprising the following steps: obtaining historical meteorological data of the location of the distributed photovoltaic grid-connected system, and obtaining a daily solar radiation intensity characteristic curve corresponding to each quarter of the location of the distributed photovoltaic grid-connected system based on the historical meteorological data, wherein the quarter includes the first to fourth quarters; obtaining a daily output power characteristic curve corresponding to each quarter of the distributed photovoltaic grid-connected system under multiple photovoltaic installed capacities based on the daily solar radiation intensity characteristic curve of each quarter; obtaining a daily load power characteristic curve of the distributed photovoltaic grid-connected system based on the power consumption history data of the load of the distributed photovoltaic grid-connected system; obtaining the standard deviation of the daily output power characteristic curve corresponding to each quarter under each photovoltaic installed capacity and the daily load power characteristic curve at the same time point, and calculating the average value of the standard deviation under each photovoltaic installed capacity to obtain the fluctuation degree value of the surplus power grid-connected power corresponding to each photovoltaic installed capacity; fitting data of the fluctuation degree value changing with the photovoltaic installed capacity, and generating a fitting mathematical function, and obtaining the optimal installed capacity of the distributed photovoltaic grid-connected system according to the fitting mathematical function.

[0008] The above-mentioned method for optimizing the installed capacity of the distributed photovoltaic grid-connected system of the present invention also has the following additional technical features:

[0009] According to one embodiment of the present invention, the daily solar radiation intensity characteristic curve of each quarter at the location of the distributed photovoltaic grid-connected system is obtained based on the historical meteorological data, specifically including: obtaining the solar radiation intensity at each hour of each quarter at the location of the distributed photovoltaic grid-connected system according to the historical meteorological data, and calculating the average value of the solar radiation intensity at each hour corresponding to each quarter; obtaining the daily solar radiation intensity characteristic curve based on the average value of the solar radiation intensity at each hour corresponding to each quarter.

[0010] According to one embodiment of the present invention, based on the daily solar radiation intensity characteristic curve of each quarter, the daily output power characteristic curve of the distributed photovoltaic grid-connected system under multiple photovoltaic installed capacities in each quarter is obtained, specifically including: obtaining the average value of the solar radiation intensity at each hour corresponding to each quarter of the distributed photovoltaic grid-connected system according to the daily solar radiation intensity characteristic curve of each quarter; calculating the daily output power of the distributed photovoltaic grid-connected system under each photovoltaic installed capacity in each quarter according to the average value of the solar radiation intensity at each hour corresponding to each quarter and the theoretical output power formula of the photovoltaic grid-connected system, and generating the daily output power characteristic curve for each quarter

[0011] According to one embodiment of the present invention, the theoretical output power formula of the photovoltaic grid-connected system is:

[0012] Among them, P S is the theoretical output power of the photovoltaic grid-connected system, H A is the solar radiation intensity, E S is the irradiance under standard conditions, P AZ is the photovoltaic installed capacity, and K is the comprehensive efficiency coefficient of the distributed photovoltaic grid-connected system.

[0013] According to one embodiment of the present invention, fitting the data of the fluctuation degree value changing with the photovoltaic installed capacity, and generating a fitting mathematical function, and obtaining the optimal installed capacity of the distributed photovoltaic grid-connected system according to the fitting mathematical function, specifically includes: using the least squares method to fit the data of the fluctuation degree value changing with the photovoltaic installed capacity, and generating a fitting mathematical function; taking the photovoltaic installed capacity corresponding to the time when the derivative of the fitting mathematical function is zero and the fluctuation degree value is minimum as the optimal installed capacity of the distributed photovoltaic grid-connected system.

[0014] The second aspect of the present invention proposes an installed capacity optimization device for a distributed photovoltaic grid-connected system, including: a first acquisition module, the first acquisition module is used to acquire historical meteorological data of the location of the distributed photovoltaic grid-connected system, and acquire the daily solar radiation intensity characteristic curve of each quarter of the location of the distributed photovoltaic grid-connected system according to the historical meteorological data, and the quarter includes the first to fourth quarters; a second acquisition module, the second acquisition module is used to acquire the daily output power characteristic curve of the distributed photovoltaic grid-connected system corresponding to each quarter under a variety of photovoltaic installed capacities according to the daily solar radiation intensity characteristic curve of each quarter; a third acquisition module, the third acquisition module is used to acquire the daily output power characteristic curve of the distributed photovoltaic grid-connected system corresponding to each quarter under a variety of photovoltaic installed capacities according to the distributed The fourth acquisition module is used to obtain the standard deviation of the daily output power characteristic curve and the daily load power characteristic curve corresponding to each quarter of each photovoltaic installed capacity at the same time point, and calculate the average value of the standard deviation under each photovoltaic installed capacity to obtain the fluctuation degree value of the surplus power grid-connected power corresponding to each photovoltaic installed capacity; the fitting module is used to fit the data of the fluctuation degree value changing with the photovoltaic installed capacity, and generate a fitting mathematical function, and obtain the optimal installed capacity of the distributed photovoltaic grid-connected system according to the fitting mathematical function.

[0015] The above-mentioned installed capacity optimization device of the distributed photovoltaic grid-connected system of the present invention also has the following additional technical features:

[0016] According to one embodiment of the present invention, the first acquisition module is specifically used to: obtain the solar radiation intensity at each hour of each quarter at the location of the distributed photovoltaic grid-connected system according to the historical meteorological data, and calculate the average value of the solar radiation intensity at each hour of each quarter; obtain the daily solar radiation intensity characteristic curve according to the average value of the solar radiation intensity at each hour of each quarter.

[0017] According to one embodiment of the present invention, the second acquisition module is specifically used to: obtain the average value of the solar radiation intensity at each hour corresponding to each quarter of the distributed photovoltaic grid-connected system according to the daily solar radiation intensity characteristic curve of each quarter; calculate the daily output power of the distributed photovoltaic grid-connected system under each photovoltaic installed capacity in each quarter according to the average value of the solar radiation intensity at each hour corresponding to each quarter and the theoretical output power formula of the photovoltaic grid-connected system, and generate the daily output power characteristic curve of each quarter.

[0018] According to one embodiment of the present invention, the theoretical output power formula of the photovoltaic grid-connected system is:

[0019]

[0020] Among them, P S is the theoretical output power of the photovoltaic grid-connected system, H A is the solar radiation intensity, E S is the irradiance under standard conditions, P AZ is the photovoltaic installed capacity, and K is the comprehensive efficiency coefficient of the distributed photovoltaic grid-connected system.

[0021] According to one embodiment of the present invention, the fitting module is specifically used to: use the least squares method to fit the data of the fluctuation degree value changing with the photovoltaic installed capacity, and generate a fitting mathematical function; take the photovoltaic installed capacity corresponding to the time when the derivative of the fitting mathematical function is zero and the fluctuation degree value is minimum as the optimal installed capacity of the distributed photovoltaic grid-connected system.

[0022] Beneficial effects of the present invention:

[0023] The present invention combines the output power of the distributed photovoltaic grid-connected system with the load power consumption, analyzes and obtains the fluctuation degree value of the surplus power grid-connected power, and obtains the optimal installed capacity according to the fluctuation degree value, thereby effectively reducing the fluctuation degree of the surplus power grid-connected power and improving the stability of the distribution system. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a flow chart of a method for optimizing the installed capacity of a distributed photovoltaic grid-connected system according to an embodiment of the present invention;

[0025] Figure 2 is a schematic diagram of a characteristic curve of daily solar radiation intensity from the first to the fourth quarter of a distributed photovoltaic grid-connected system according to a specific example of the present invention;

[0026] Figure 3 is a schematic diagram of daily output power characteristic curves of a distributed photovoltaic grid-connected system from the first to the fourth quarter according to a specific example of the present invention;

[0027] Figure 4 is a schematic diagram of a daily load power characteristic curve of a distributed photovoltaic grid-connected system according to a specific example of the present invention;

[0028] Figure 5 is a graph of standard deviations of daily output power characteristic curves from the first to fourth quarters and daily load power characteristic curves at the same time points according to a specific example of the present invention;

[0029] Figure 6 is a schematic diagram of data of using least square method to fit fluctuation degree value with photovoltaic installed capacity according to a specific example of the present invention;

[0030] Figure 7 Detailed description of the invention The figure is a block diagram of an installed capacity optimization device for a distributed photovoltaic grid-connected system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Figure 1 FIG. 1 is a flow chart of a method for optimizing the installed capacity of a distributed photovoltaic grid-connected system according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps:

[0033] S1, obtaining historical meteorological data of the location of the distributed photovoltaic grid-connected system, and obtaining the daily solar radiation intensity characteristic curve corresponding to each quarter of the location of the distributed photovoltaic grid-connected system based on the historical meteorological data, wherein the quarters include the first to fourth quarters.

[0034] Furthermore, a daily solar radiation intensity characteristic curve of each quarter at the location of the distributed photovoltaic grid-connected system is obtained based on historical meteorological data, specifically including: obtaining the solar radiation intensity at each hour of each quarter at the location of the distributed photovoltaic grid-connected system based on historical meteorological data, and calculating the average value of the solar radiation intensity at each hour of each quarter; obtaining the daily solar radiation intensity characteristic curve based on the average value of the solar radiation intensity at each hour of each quarter.

[0035] Specifically, the historical meteorological data of the location of the distributed photovoltaic grid-connected system is obtained, and the average solar radiation intensity at the same time point every day from the first to the fourth quarter (spring, summer, autumn, and winter) is calculated according to the historical meteorology. For example, the average solar radiation intensity at each hour of all days in the first quarter is calculated as the solar radiation intensity at the corresponding time point, and finally a daily solar radiation intensity characteristic curve is generated. The same calculation is performed for other quarters, and finally the following is generated: Figure 2 The daily solar radiation intensity characteristic curves from the first to the fourth quarter are shown.

[0036] S2, according to the daily solar radiation intensity characteristic curve of each quarter, obtain the daily output power characteristic curve of the distributed photovoltaic grid-connected system corresponding to each quarter under various photovoltaic installed capacities.

[0037] Further, according to an embodiment of the present invention, based on the daily solar radiation intensity characteristic curve of each quarter, the daily output power characteristic curve of the distributed photovoltaic grid-connected system under multiple photovoltaic installed capacities in each quarter is obtained, specifically including: according to the daily solar radiation intensity characteristic curve of each quarter, the average value of the solar radiation intensity at each hour corresponding to each quarter of the distributed photovoltaic grid-connected system is obtained; according to the average value of the solar radiation intensity at each hour corresponding to each quarter and the theoretical output power formula of the photovoltaic grid-connected system, the daily output power of the distributed photovoltaic grid-connected system under each photovoltaic installed capacity in each quarter is calculated, and the daily output power characteristic curve of each quarter is generated.

[0038] According to one embodiment of the present invention, the theoretical output power formula of the photovoltaic grid-connected system is:

[0039]

[0040] Among them, P S is the output power of the photovoltaic grid-connected system, H A is the solar radiation intensity, E S is the irradiance under standard conditions, P AZ is the photovoltaic installed capacity, K is the comprehensive efficiency coefficient of the distributed photovoltaic grid-connected system. E can generally be taken as 1000W / m 2The comprehensive efficiency coefficient K mainly includes: the temperature correction coefficient of photovoltaic module conversion efficiency, the inclination angle of photovoltaic module installation, the azimuth correction coefficient, the surface contamination correction coefficient of photovoltaic module, the type correction coefficient of photovoltaic module, the inverter efficiency, and the line loss. Generally, K=0.75~0.85.

[0041] Specifically, first according to Figure 2 The daily solar radiation intensity characteristic curve of each quarter in the distributed photovoltaic grid-connected system is used to obtain the average solar radiation intensity of each hour corresponding to each quarter. Then, according to the theoretical output power formula of the photovoltaic grid-connected system mentioned above, the average solar radiation intensity of each hour corresponding to each quarter is substituted into the theoretical output power formula of the photovoltaic grid-connected system mentioned above, and the daily output power of each quarter under different photovoltaic installed capacities can be obtained, and the generated Figure 3 The daily output power characteristic curve for each quarter is shown in Figure 1. The photovoltaic installed capacity is the commonly used installed capacity of distributed photovoltaic grid-connected systems, such as 1000kWP-2400kWP. Figure 3 The figure shows the daily output power characteristic curve for each quarter when the photovoltaic installed capacity is 1000kWP and K is 0.8.

[0042] It is understandable that since there is a certain error between the theoretical output power and the actual output power of the photovoltaic grid-connected system, when the output power of similar photovoltaic grid-connected systems at different solar radiation intensities can be obtained, the measured data is preferred. When there is no measured data of similar projects, the output power at different solar radiation intensities is calculated by the theoretical output power function of the photovoltaic grid-connected system mentioned above.

[0043] S3, obtaining a daily load power characteristic curve of the distributed photovoltaic grid-connected system according to the power consumption history data of the load of the distributed photovoltaic grid-connected system.

[0044] Specifically, the load power consumption data selects the measured data of the total electric energy meter in the past year, and the average power consumption at the same time point is taken as the load power consumption characteristic value at that time point, and the daily load power consumption characteristic curve is obtained, such as Figure 4 shown.

[0045] S4, obtaining the standard deviation of the daily output power characteristic curve and the daily load power characteristic curve corresponding to each quarter of each photovoltaic installed capacity at the same time point, and calculating the average value of the standard deviation under each photovoltaic installed capacity to obtain the fluctuation degree value of the surplus power grid-connected power corresponding to each photovoltaic installed capacity.

[0046] Specifically, under each installed capacity, the daily output power characteristic curves of the four quarters are respectively differentiated from their corresponding daily load power characteristic curves, and the standard deviation values ​​of the daily output power and the daily load power at the same time point of each quarter are obtained in turn, and 4 standard deviation values ​​are obtained. The average of the 4 standard deviation values ​​is then taken as the fluctuation degree value of the surplus power online power under the installed capacity. The size of the fluctuation degree value can represent the fluctuation degree of the surplus power online power.

[0047] For example, Figure 5 As shown, Figure 5 It is a graph of the standard deviation of the daily output power characteristic curve from the first to the fourth quarter and the daily load power characteristic curve at the same time point according to a specific example of the present invention. If the difference is positive, it means that the photovoltaic grid-connected system is injecting power into the distribution network; if the difference is negative, it means that the load is absorbing power from the distribution network. Among them, Figure 5 The standard deviations of the China-Japan output power characteristic curve and the daily load power characteristic curve at the same time point are S(1)=141.21, S(2)=94.79, S(3)=167.32, and S(4)=179.31, respectively. After averaging S(1)-S(4), the fluctuation degree of the surplus power on-grid power of the distributed photovoltaic grid-connected system under the photovoltaic installed capacity (1000kWP) is obtained, which is 145.65.

[0048] The above steps are used to obtain the fluctuation degree values ​​of the surplus power grid-connected power corresponding to various photovoltaic installed capacities in turn, as shown in the following Table 1. Table 1 shows the fluctuation degree values ​​of the surplus power grid-connected power corresponding to 14 commonly used photovoltaic installed capacities.

[0049] Table 1

[0050]

[0051]

[0052] S5, fitting the data of fluctuation degree value changing with photovoltaic installed capacity, and generating a fitting mathematical function, and obtaining the optimal installed capacity of the distributed photovoltaic grid-connected system according to the fitting mathematical function.

[0053] Furthermore, according to an embodiment of the present invention, the optimal installed capacity of the distributed photovoltaic grid-connected system is obtained based on the fitting mathematical function, specifically including: using the least squares method to fit the data of the fluctuation degree value changing with the photovoltaic installed capacity, and generating a fitting mathematical function; taking the photovoltaic installed capacity corresponding to the time when the derivative of the fitting mathematical function is zero and the fluctuation degree value is the smallest as the optimal installed capacity of the distributed photovoltaic grid-connected system.

[0054] Specifically, N sets of data whose fluctuation values ​​vary with the installed capacity of photovoltaic power are input into a two-dimensional coordinate plane, such as Figure 6As shown in the figure, the least squares method is used to fit the data of fluctuation degree value changing with photovoltaic installed capacity, and the mathematical function of fluctuation degree value y changing with photovoltaic installed capacity x is determined as follows:

[0055] y=0.0000644438x 2 -0.1931856638x+274.3903704697;

[0056] Let the derivative of the above formula be 0, and we get:

[0057] x=1499

[0058] This value corresponds to the lowest fluctuation level, so the optimal installed capacity is 1499kWP.

[0059] In summary, according to the installed capacity optimization method of the distributed photovoltaic grid-connected system of the embodiment of the present invention, the historical meteorological data of the location of the distributed photovoltaic grid-connected system is obtained, and the daily solar radiation intensity characteristic curve corresponding to each quarter of the location of the distributed photovoltaic grid-connected system is obtained according to the historical meteorological data. According to the daily solar radiation intensity characteristic curve of each quarter, the daily output power characteristic curve corresponding to each quarter of the distributed photovoltaic grid-connected system under multiple photovoltaic installed capacities is obtained, and according to the power consumption history data of the load of the distributed photovoltaic grid-connected system, the daily load power characteristic curve of the distributed photovoltaic grid-connected system is obtained, and the standard deviation of the daily output power characteristic curve and the daily load power characteristic curve corresponding to each quarter under each photovoltaic installed capacity at the same time point is obtained, and the average value of the standard deviation under each photovoltaic installed capacity is calculated to obtain the fluctuation degree value of the surplus power on-grid power corresponding to each photovoltaic installed capacity, fit the data of the fluctuation degree value changing with the photovoltaic installed capacity, and generate a fitting mathematical function, and obtain the optimal installed capacity of the distributed photovoltaic grid-connected system according to the fitting mathematical function. Therefore, this method combines the output power of the distributed photovoltaic grid-connected system with the load power consumption, analyzes the fluctuation degree of the surplus power grid-connected power, and obtains the optimal installed capacity according to the fluctuation degree value, thereby effectively reducing the fluctuation degree of the surplus power grid-connected power and improving the stability of the distribution system.

[0060] Corresponding to the above-mentioned method for optimizing the installed capacity of a distributed photovoltaic grid-connected system, the present invention also proposes an installed capacity optimization device for a distributed photovoltaic grid-connected system. Since the device embodiment of the present invention corresponds to the above-mentioned method embodiment, details not disclosed in the device embodiment can be referred to the above-mentioned method embodiment, and will not be repeated in the present invention.

[0061] Figure 7 FIG. 1 is a block diagram of an installed capacity optimization device for a distributed photovoltaic grid-connected system according to an embodiment of the present invention. Figure 7As shown, the device includes: a first acquisition module 1, a second acquisition module 2, a third acquisition module 3, a fourth acquisition module 4 and a fitting module 5.

[0062] The first acquisition module 1 is used to obtain the historical meteorological data of the location of the distributed photovoltaic grid-connected system, and obtain the daily solar radiation intensity characteristic curve of each quarter of the location of the distributed photovoltaic grid-connected system based on the historical meteorological data, and the quarter includes the first to fourth quarters; the second acquisition module 2 is used to obtain the daily output power characteristic curve corresponding to each quarter of the distributed photovoltaic grid-connected system under various photovoltaic installed capacities based on the daily solar radiation intensity characteristic curve of each quarter; the third acquisition module 3 is used to obtain the daily load power characteristic curve of the distributed photovoltaic grid-connected system based on the power consumption history data of the load of the distributed photovoltaic grid-connected system; the fourth acquisition module 4 is used to obtain the standard deviation value of the daily output power characteristic curve corresponding to each quarter under each photovoltaic installed capacity and the daily load power characteristic curve at the same time point, and calculate the average value of the standard deviation value under each photovoltaic installed capacity to obtain the fluctuation degree value of the surplus power grid-connected power corresponding to each photovoltaic installed capacity; the fitting module 5 is used to fit the data of the fluctuation degree value changing with the photovoltaic installed capacity, and generate a fitting mathematical function, and obtain the optimal installed capacity of the distributed photovoltaic grid-connected system according to the fitting mathematical function.

[0063] According to one embodiment of the present invention, the first acquisition module 1 is specifically used to: obtain the solar radiation intensity at each hour of each quarter at the location of the distributed photovoltaic grid-connected system based on historical meteorological data, and calculate the average value of the solar radiation intensity at each hour of each quarter; obtain the daily solar radiation intensity characteristic curve based on the average value of the solar radiation intensity at each hour of each quarter.

[0064] According to one embodiment of the present invention, the second acquisition module 2 is specifically used to: obtain the average value of the solar radiation intensity at each hour corresponding to each quarter of the distributed photovoltaic grid-connected system according to the daily solar radiation intensity characteristic curve of each quarter; calculate the daily output power of the distributed photovoltaic grid-connected system under each photovoltaic installed capacity in each quarter according to the average value of the solar radiation intensity at each hour corresponding to each quarter and the theoretical output power formula of the photovoltaic grid-connected system, and generate the daily output power characteristic curve of each quarter.

[0065] According to one embodiment of the present invention, the theoretical output power formula of the photovoltaic grid-connected system is:

[0066]

[0067] Among them, P S is the theoretical output power of the photovoltaic grid-connected system, H A is the solar radiation intensity, E S is the irradiance under standard conditions, PAZ is the photovoltaic installed capacity, and K is the comprehensive efficiency coefficient of the distributed photovoltaic grid-connected system.

[0068] According to one embodiment of the present invention, the fitting module 5 is specifically used to: use the least squares method to fit the data of the fluctuation degree value changing with the photovoltaic installed capacity, and generate a fitting mathematical function; and use the photovoltaic installed capacity corresponding to the time when the derivative of the fitting mathematical function is zero and the fluctuation degree value is the smallest as the optimal installed capacity of the distributed photovoltaic grid-connected system.

[0069] In summary, according to the installed capacity optimization device of the distributed photovoltaic grid-connected system according to the embodiment of the present invention, the output power of the distributed photovoltaic grid-connected system and the load power are combined to analyze the fluctuation degree value of the surplus power grid-connected power, and the optimal installed capacity is obtained according to the fluctuation degree value, thereby effectively reducing the fluctuation degree of the surplus power grid-connected power and improving the stability of the distribution system.

[0070] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0071] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for optimizing the installed capacity of a distributed photovoltaic grid-connected system, characterized in that: The following steps are involved: Acquire historical meteorological data of the location of the distributed photovoltaic grid-connected system, and acquire a daily solar radiation intensity characteristic curve corresponding to each quarter of the location of the distributed photovoltaic grid-connected system according to the historical meteorological data, wherein the quarters include the first to fourth quarters; According to the daily solar radiation intensity characteristic curve of each quarter, obtaining the daily output power characteristic curve corresponding to each quarter of the distributed photovoltaic grid-connected system under various photovoltaic installed capacities; According to the power consumption history data of the load of the distributed photovoltaic grid-connected system, a daily load power consumption characteristic curve of the distributed photovoltaic grid-connected system is obtained; Obtain the standard deviation of the daily output power characteristic curve and the daily load power characteristic curve corresponding to each quarter under each photovoltaic installed capacity at the same time point, and calculate the average value of the standard deviation under each photovoltaic installed capacity to obtain the fluctuation degree value of the surplus power grid-connected power corresponding to each photovoltaic installed capacity; Fitting data of fluctuation degree values ​​changing with the photovoltaic installed capacity, and generating a fitting mathematical function, and obtaining the optimal installed capacity of the distributed photovoltaic grid-connected system according to the fitting mathematical function; The method of fitting the data of fluctuation degree value changing with the photovoltaic installed capacity and generating a fitting mathematical function, and obtaining the optimal installed capacity of the distributed photovoltaic grid-connected system according to the fitting mathematical function specifically includes: Using the least square method to fit the data of the fluctuation degree value changing with the photovoltaic installed capacity, and generating a fitting mathematical function; The photovoltaic installed capacity corresponding to the time when the derivative of the fitting mathematical function is zero and the fluctuation degree value is minimum is taken as the optimal installed capacity of the distributed photovoltaic grid-connected system.

2. The method for optimizing installed capacity of a distributed photovoltaic grid-connected system according to claim 1, characterized in that: The daily solar radiation intensity characteristic curve of each quarter at the location of the distributed photovoltaic grid-connected system is obtained according to the historical meteorological data, specifically including: According to the historical meteorological data, the solar radiation intensity at each hour of each quarter at the location of the distributed photovoltaic grid-connected system is obtained, and the average solar radiation intensity at each hour of each quarter is calculated; The daily solar radiation intensity characteristic curve is obtained according to the average value of the solar radiation intensity at each hour corresponding to each quarter.

3. The method for optimizing installed capacity of a distributed photovoltaic grid-connected system according to claim 1, characterized in that: According to the daily solar radiation intensity characteristic curve of each quarter, the daily output power characteristic curve of the distributed photovoltaic grid-connected system in each quarter under various photovoltaic installed capacities is obtained, specifically including: Obtaining the average value of the solar radiation intensity of each hour corresponding to each quarter of the distributed photovoltaic grid-connected system according to the daily solar radiation intensity characteristic curve of each quarter; According to the average value of the solar radiation intensity at each hour corresponding to each quarter and the theoretical output power formula of the photovoltaic grid-connected system, the daily output power of the distributed photovoltaic grid-connected system in each quarter under each photovoltaic installed capacity is calculated, and a daily output power characteristic curve for each quarter is generated.

4. The method for optimizing installed capacity of a distributed photovoltaic grid-connected system according to claim 3, characterized in that: The theoretical output power formula of the photovoltaic grid-connected system is: Among them, P S is the output power of the photovoltaic grid-connected system, H A is the solar radiation intensity, E S is the irradiance under standard conditions, P AZ is the photovoltaic installed capacity, and K is the comprehensive efficiency coefficient of the distributed photovoltaic grid-connected system.

5. A device for optimizing installed capacity of a distributed photovoltaic grid-connected system, characterized in that: include: A first acquisition module, the first acquisition module is used to acquire historical meteorological data of the location of the distributed photovoltaic grid-connected system, and acquire a daily solar radiation intensity characteristic curve of each quarter of the location of the distributed photovoltaic grid-connected system according to the historical meteorological data, wherein the quarter includes the first to fourth quarters; A second acquisition module, the second acquisition module is used to obtain the daily output power characteristic curve corresponding to each quarter of the distributed photovoltaic grid-connected system under multiple photovoltaic installed capacities according to the daily solar radiation intensity characteristic curve of each quarter; A third acquisition module, the third acquisition module is used to acquire a daily load power characteristic curve of the distributed photovoltaic grid-connected system according to the power consumption history data of the load of the distributed photovoltaic grid-connected system; A fourth acquisition module, the fourth acquisition module is used to obtain the standard deviation value of the daily output power characteristic curve and the daily load power characteristic curve corresponding to each quarter under each photovoltaic installed capacity at the same time point, and calculate the average value of the standard deviation value under each photovoltaic installed capacity to obtain the fluctuation degree value of the surplus power grid-connected power corresponding to each photovoltaic installed capacity; A fitting module, the fitting module is used to fit the data of the fluctuation degree value changing with the photovoltaic installed capacity, and generate a fitting mathematical function, and obtain the optimal installed capacity of the distributed photovoltaic grid-connected system according to the fitting mathematical function; The fitting module is specifically used to: use the least squares method to fit the data of the fluctuation degree value changing with the photovoltaic installed capacity, and generate a fitting mathematical function; and take the photovoltaic installed capacity corresponding to the time when the derivative of the fitting mathematical function is zero and the fluctuation degree value is minimum as the optimal installed capacity of the distributed photovoltaic grid-connected system.

6. The installed capacity optimization device for a distributed photovoltaic grid-connected system according to claim 5, characterized in that: The first acquisition module is specifically used for: According to the historical meteorological data, the solar radiation intensity at each hour of each quarter at the location of the distributed photovoltaic grid-connected system is obtained, and the average solar radiation intensity at each hour of each quarter is calculated; The daily solar radiation intensity characteristic curve is obtained according to the average value of the solar radiation intensity at each hour corresponding to each quarter.

7. The installed capacity optimization device for a distributed photovoltaic grid-connected system according to claim 5, characterized in that: The second acquisition module is specifically used for: Obtaining the average value of the solar radiation intensity of each hour corresponding to each quarter of the distributed photovoltaic grid-connected system according to the daily solar radiation intensity characteristic curve of each quarter; According to the average value of the solar radiation intensity at each hour corresponding to each quarter and the theoretical output power formula of the photovoltaic grid-connected system, the daily output power of the distributed photovoltaic grid-connected system in each quarter under each photovoltaic installed capacity is calculated, and a daily output power characteristic curve for each quarter is generated.

8. The installed capacity optimization device for a distributed photovoltaic grid-connected system according to claim 7, characterized in that: The theoretical output power formula of the photovoltaic grid-connected system is: Among them, P S is the output power of the photovoltaic grid-connected system, H A is the solar radiation intensity, E S is the irradiance under standard conditions, P AZ is the photovoltaic installed capacity, and K is the comprehensive efficiency coefficient of the distributed photovoltaic grid-connected system.

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