A solar radiation stability assessment method, device, equipment and medium

Abstract

The embodiments of this specification provide a method, device, equipment and medium for evaluating solar radiation stability, wherein the method includes: obtaining historical solar radiation observation data of a target area, calculating the average state of the evolution of solar radiation intensity with a preset time interval in a preset time period as a reference sequence; collecting the solar radiation intensity of a target day as a first sequence according to the preset time interval; calculating the probability distribution functions of the reference sequence and the first sequence respectively, and calculating the Wasserstein distance of the two probability distribution functions, and determining the solar radiation stability of the corresponding day according to the Wasserstein distance, so as to solve the technical problem that the existing quantitative evaluation indicators mainly consider high-frequency fluctuations within a cycle, while low-frequency fluctuation information within a cycle is rarely considered, resulting in inaccurate evaluation results.

Description

Technical Field

[0001] The present invention relates to the field of renewable energy analysis technology, and in particular to a solar radiation stability assessment method, device, equipment and medium. Background Art

[0002] With the steady development of photovoltaic power generation, the challenges and impacts brought by large-scale photovoltaic access to the power grid will become increasingly significant. The main reason is that photovoltaic output is volatile.

[0003] The fluctuation of solar radiation on the surface on a daily scale is an important factor affecting the stability of photovoltaic power generation. Therefore, quantitative evaluation of solar radiation stability is essential for the photovoltaic power generation industry. Existing quantitative evaluation indicators mainly consider high-frequency fluctuations within a cycle, while low-frequency fluctuations within a cycle are rarely considered. For reference, "Quantifiers for the solar irradiance variability: A new perspective" published on pages 606-616 of the Solar Energy journal in November 2018, however, in terms of the stability of photovoltaic power generation, the impact of low-frequency fluctuations is often more significant than that of high-frequency fluctuations, which leads to inaccurate evaluation results. In view of this, it is urgent to provide a method for evaluating the stability of solar radiation that considers both high- and low-frequency fluctuations. Summary of the invention

[0004] In order to overcome the problems existing in the related technology, the present disclosure provides a solar radiation stability assessment method, device, equipment and medium to solve the technical problem that the existing quantitative assessment indicators mainly consider high-frequency fluctuations within the cycle, while low-frequency fluctuation information within the cycle is rarely considered, resulting in inaccurate assessment results.

[0005] One or more embodiments of this specification provide a method for evaluating solar radiation stability, including the steps of:

[0006] Obtain historical solar radiation intensity data collected in the target area, and calculate the average state of the solar radiation intensity evolving with the preset time interval within the preset time period as a reference sequence;

[0007] According to preset time intervals, the solar radiation intensity in the target day is collected as a plurality of first sequences;

[0008] The first probability distribution function of the reference sequence and the second probability distribution functions of the multiple first sequences are calculated, and the Wasserstein distance between the first probability distribution function and each second probability distribution function is calculated respectively, and the solar radiation stability in the corresponding day is determined according to the Wasserstein distance.

[0009] Furthermore, the average state of the solar radiation intensity evolving with the preset time interval during the preset time period is calculated as follows:

[0010]

[0011] Among them, G ref (i) is the i-th solar radiation intensity in the reference sequence, G his (n, i) is the i-th solar radiation intensity on the n-th day in the historical solar radiation intensity data, and N is the number of days.

[0012] Furthermore, the probability distribution of the reference sequence is calculated with reference to the following formula:

[0013]

[0014] The probability distribution of the first sequence is calculated with reference to the following formula:

[0015]

[0016] in, is the probability of the i-th reference sequence value, is the probability of the ith first sequence value, and T is the number of records of solar radiation observations within the day.

[0017] Furthermore, the Wasserstein distance is calculated as follows:

[0018]

[0019] Wherein, the first probability distribution of the reference sequence and the second probability distribution of the first sequence are μ and v respectively, π∈Π(μ,v) is the set of all possible joint distributions of the first probability distribution of the reference sequence and the second probability distribution of the first sequence, defined in Inf is the lower bound, which means taking the value with the minimum cost among all possible joint distributions, and p is the order of Wasserstein distance.

[0020] One or more embodiments of this specification provide a solar radiation stability assessment device, including:

[0021] The first data collection module is used to obtain historical solar radiation intensity data collected in the target area;

[0022] The first calculation module is used to calculate the average state of the solar radiation intensity evolving with the preset time interval within the preset time period as a reference sequence;

[0023] The second data collection module is used to collect the solar radiation intensity of the target day as a first sequence according to a preset time interval;

[0024] The second calculation module is used to calculate the first probability distribution function of the reference sequence and the second probability distribution functions of multiple first sequences, and respectively calculate the Wasserstein distance between the first probability distribution function and each second probability distribution function, and determine the solar radiation stability of the corresponding day according to the Wasserstein distance.

[0025] Furthermore, the first calculation module is configured to calculate the average state of the solar radiation intensity evolving with the preset time interval within the preset time period as follows:

[0026]

[0027] Among them, G ref (i) is the i-th solar radiation intensity in the reference sequence, G his (n, i) is the i-th solar radiation intensity on the n-th day in the historical solar radiation intensity data, and N is the number of days.

[0028] Further, the second calculation module is configured to calculate the probability distribution of the reference sequence with reference to the following formula:

[0029]

[0030] The probability distribution of the first sequence is calculated with reference to the following formula:

[0031]

[0032] in, is the probability of the i-th reference sequence value, is the probability of the ith first sequence value, and T is the number of records of solar radiation observations within the day.

[0033] Further, the second calculation module is configured to calculate the Wasserstein distance between two probability distribution functions with reference to the following formula:

[0034]

[0035] Wherein, the first probability distribution of the reference sequence and the second probability distribution of the first sequence are μ and v respectively, π∈Π(μ,v) is the set of all possible joint distributions of the first probability distribution of the reference sequence and the second probability distribution of the first sequence, defined in Inf is the lower bound, which means taking the value with the minimum cost among all possible joint distributions, and p is the order of Wasserstein distance.

[0036] One or more embodiments of the present specification provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the solar radiation stability assessment method as described in any one of the above items when executing the computer program.

[0037] One or more embodiments of the present specification provide a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of any of the above-mentioned solar radiation stability assessment methods are implemented.

[0038] The present invention provides a solar radiation stability assessment method, device, equipment and medium, which have the advantage that the historical data and target day data used to analyze the solar radiation stability do not only consider the impact of high-frequency fluctuations on solar radiation stability, but also include high-frequency and low-frequency solar radiation fluctuation information, so that the measurement of solar radiation stability is more comprehensive. The method provided in this embodiment is simple to implement, and can determine how solar radiation changes over time within a day, and determine the solar radiation stability of multiple different sites to be selected in the same area or different areas according to needs, providing an effective solution for resource assessment in wind farm site selection planning. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate one or more embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0040] Figure 1 A flow chart of a solar radiation stability assessment method provided for one or more embodiments of this specification;

[0041] Figure 2 A block diagram of a solar radiation stability assessment device provided for one or more embodiments of this specification;

[0042] Figure 3 A schematic diagram of the structure of a computer device provided for one or more embodiments of this specification. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below in conjunction with the drawings in one or more embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the protection scope of the present invention.

[0044] The present invention is described in detail below in conjunction with specific implementation methods and the accompanying drawings.

[0045] Method Embodiment

[0046] According to an embodiment of the present invention, a method for evaluating solar radiation stability is provided. Figure 1 FIG. 2 is a flow chart of a solar radiation stability evaluation method provided in this embodiment. The solar radiation stability evaluation method according to an embodiment of the present invention includes:

[0047] Step S1, obtaining historical solar radiation intensity data collected in a target area during a time period, and calculating the average state of solar radiation intensity evolving with a preset time interval during a preset time period as a reference sequence;

[0048] In this embodiment, the solar radiation intensity at the ground level can be observed by a solar radiation measuring instrument and the like and used as historical data.

[0049] In this embodiment, the calculation of the average state of the solar radiation intensity evolving with the preset time interval within the preset time period is referred to the following formula:

[0050]

[0051] Among them, G ref (i) is the solar radiation intensity of the i-th record in the reference sequence, G his (n, i) is the i-th solar radiation intensity on the n-th day recorded in the historical solar radiation intensity data, and N is the number of days. In this embodiment, N is at least 365 days in a year.

[0052] Step S2: collecting solar radiation intensities of a plurality of target days as a plurality of first sequences according to preset time intervals.

[0053] Step S3, calculating the first probability distribution function of the reference sequence and the second probability distribution function of each first sequence, and respectively calculating the Wasserstein distance between the first probability distribution function and each second probability distribution function, and determining the solar radiation stability of the corresponding day according to the Wasserstein distance.

[0054] In this embodiment, the probability distribution of the reference sequence is calculated with reference to the following formula:

[0055]

[0056] The first sequence probability distribution is calculated by referring to the following formula:

[0057]

[0058] in, is the probability of the i-th reference sequence value, is the probability of the i-th first sequence value, and T is the total number of records of solar radiation observations in a day. It should be noted that the collection time interval and total number T of the historical solar radiation intensity of the target area and the solar radiation intensity of the target day are the same, and the initial collection time point is also the same.

[0059] Then, the first probability distribution of the reference sequence and the second probability distribution of the first sequence are set to μ and v respectively, and the Wasserstein distance between the two probability distribution functions is calculated as follows:

[0060]

[0061] Where μ and v are defined in (real number space mapped to all moments of a day), π∈Π(μ,v) is the set of all possible joint distributions of the first probability distribution of the reference sequence and the second probability distribution of the first sequence, defined in Inf is the lower bound, which means taking the value of the minimum cost among all possible joint distributions, p is the order of the Wasserstein distance, where p=1, and |xy|dπ(x,y) represents the minimum cost required to move from the x position in μ to the y position in v.

[0062] In this embodiment, the relative ranking of solar radiation instability can be obtained by comparing the Wasserstein distances corresponding to different days. The larger the Wasserstein distance, the more unstable the solar radiation on that day. In this embodiment, the solar radiation stability of the day is quantified according to the Wasserstein distance between the solar radiation sequence of the target day and the reference sequence. The Wasserstein distance is calculated to determine the difference between the distribution of the historical solar radiation state and the solar radiation state of the target day, so as to better quantify and determine the solar radiation stability of the target day.

[0063] This embodiment uses long-term historical solar radiation intensity observation data and calculates the average state to filter out disturbances, forming the evolution of solar radiation intensity over time under "general circumstances". This sequence can be used as a standard, that is, a reference sequence, and then the sequence of the acquired specific target day is compared. The role of using Wasserstein distance in this embodiment is to measure the difference between the two distributions. By comparing the difference in the evolution of solar radiation intensity over time under "general circumstances" and the specific target day, the stability of solar radiation can be obtained. Before calculating the Wasserstein distance, the reference sequence and the target day sequence are first converted into probability distributions. On the one hand, the Wasserstein distance requires that the two objects of comparison are probability distributions. On the other hand, the influence of the direct sun point is eliminated by normalization (making the sum of the intra-day values ​​​​all 1) (for example, the direct sun point in summer is northerly than in winter, so the overall radiation in summer is greater than in winter).

[0064] The method of this embodiment is used to analyze the historical data and target day data of solar radiation stability. It does not only consider the impact of high-frequency fluctuations on solar radiation stability, but also includes high-frequency and low-frequency solar radiation fluctuation information, which measures the stability of solar radiation more comprehensively. The method provided in this embodiment is simple to implement and can determine how solar radiation changes over time within a day, and determine the multi-day solar radiation stability of multiple different sites to be selected in the same area or different areas according to needs, providing an effective method for resource evaluation in wind farm site selection planning.

[0065] Device Embodiment

[0066] According to an embodiment of the present invention, a solar radiation stability assessment device is provided. Figure 2 As shown in FIG. 1 , a block diagram of a solar radiation stability evaluation device provided in this embodiment is provided. The solar radiation stability evaluation device according to an embodiment of the present invention includes:

[0067] The first data collection module 10 is used to obtain historical solar radiation intensity data collected in a target area within a time period.

[0068] In this embodiment, the solar radiation intensity at the ground level can be observed by a solar radiation measuring instrument and the like and used as historical data.

[0069] The first calculation module 20 is used to calculate the average state of the solar radiation intensity evolving with the preset time interval within the preset time period as a reference sequence;

[0070] In this embodiment, the calculation of the average state of the solar radiation intensity evolving with the preset time interval within the preset time period is referred to the following formula:

[0071]

[0072] Among them, G ref(i) is the solar radiation intensity of the i-th in the reference sequence, G his (n, i) is the i-th solar radiation intensity on the n-th day in the historical solar radiation observation data, and N is the number of days.

[0073] The second data collection module 30 is used to collect solar radiation intensity in a plurality of target days as a first sequence according to a preset time interval.

[0074] The second calculation module 40 is used to calculate the first probability distribution function of the reference sequence and the second probability distribution function of each first sequence, and respectively calculate the Wasserstein distance between the first probability distribution function and each second probability distribution function, and determine the solar radiation stability of the corresponding day according to the Wasserstein distance.

[0075] In this embodiment, the probability distribution of the reference sequence is calculated with reference to the following formula:

[0076]

[0077] The first sequence probability distribution is calculated by referring to the following formula:

[0078]

[0079] in, is the probability of the i-th reference sequence value, is the probability of the ith first sequence value, and T is the total number of records of solar radiation observations within the day.

[0080] Then, the first probability distribution of the reference sequence and the second probability distribution of the first sequence are set to μ and v respectively, and the Wasserstein distance between the two probability distribution functions is calculated as follows:

[0081]

[0082] Where π∈Π(μ,v) is the set of all possible joint distributions of the reference sequence probability distribution and the first sequence probability distribution, defined in Inf is the lower bound, which means taking the value with the minimum cost among all possible joint distributions, and p is the order of Wasserstein distance.

[0083] In this embodiment, the relative ranking of solar radiation instability can be obtained by comparing the Wasserstein distances corresponding to different days. The larger the Wasserstein distance, the more unstable the solar radiation on that day. In this embodiment, the solar radiation stability of the day is quantified according to the Wasserstein distance between the solar radiation sequence of the target day and the reference sequence. The Wasserstein distance calculation determines the distance between the historical solar radiation state and the solar radiation state of the target day, which can better quantify and determine the solar radiation stability of the target day.

[0084] The device of the present embodiment, which is used to analyze the historical data and target day data of solar radiation stability, does not only consider the impact of high-frequency fluctuations on solar radiation stability, but also includes high-frequency and low-frequency solar radiation fluctuation information, which measures the stability of solar radiation more comprehensively. The method provided in the present embodiment is simple to implement, and can determine how solar radiation changes over time within a day, and determine the multi-day solar radiation stability of multiple different sites to be selected in the same area or different areas according to needs, providing an effective method for resource assessment in wind farm site selection planning.

[0085] The embodiment of the present invention is an apparatus embodiment corresponding to the above-mentioned method embodiment. The specific operations of the processing steps of each module can be understood by referring to the description of the method embodiment, which will not be repeated here.

[0086] like Figure 3 As shown, the present invention further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the solar radiation stability evaluation method in the above embodiment is implemented. Alternatively, when the computer program is executed by a processor, the solar radiation stability evaluation method in the above embodiment is implemented. When the computer program is executed by the processor, the following method steps are implemented:

[0087] Step S1, obtaining historical solar radiation observation data collected in the target area, and calculating the average state of the evolution of solar radiation intensity over a preset time period with a preset time interval as a reference sequence;

[0088] Step S2, collecting solar radiation intensities of multiple target days as a first sequence according to preset time intervals;

[0089] Step S3, calculating the first probability distribution function of the reference sequence and the second probability distribution function of each first sequence, and respectively calculating the Wasserstein distance between the first probability distribution function and each second probability distribution function, and determining the solar radiation stability of the corresponding day according to the Wasserstein distance.

[0090] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The device and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and the contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A method for evaluating solar radiation stability, characterized in that: Includes steps: Obtain historical solar radiation intensity data collected in the target area, and calculate the average state of the solar radiation intensity evolving with the preset time interval within the preset time period as a reference sequence; According to preset time intervals, the solar radiation intensity in the target day is collected as a plurality of first sequences; Calculate the first probability distribution function of the reference sequence and the second probability distribution functions of the multiple first sequences, and respectively calculate the Wasserstein distance between the first probability distribution function and each second probability distribution function, and determine the solar radiation stability of the corresponding day according to the Wasserstein distance; The average state of the solar radiation intensity evolving with the preset time interval during the preset time period is calculated as follows: Among them, G ref (i) is the i-th solar radiation intensity in the reference sequence, G his (n, i) is the i-th solar radiation intensity on the n-th day in the historical solar radiation intensity data, and N is the number of days; The probability distribution calculation of the reference sequence refers to the following formula: The probability distribution of the first sequence is calculated with reference to the following formula: in, is the probability of the i-th reference sequence value, is the probability of the ith first sequence value, and T is the number of records of solar radiation observations within the day.

2. The solar radiation stability evaluation method according to claim 1, characterized in that: The Wasserstein distance is calculated as follows: Wherein, the first probability distribution of the reference sequence and the second probability distribution of the first sequence are μ and v respectively, π∈Π(μ, v) is the set of all possible joint distributions of the first probability distribution of the reference sequence and the second probability distribution of the first sequence, defined in Inf is the lower bound, which means taking the value with the minimum cost among all possible joint distributions, and p is the order of the Wasserstein distance.

3. A solar radiation stability assessment device, characterized in that: include: The first data collection module is used to obtain historical solar radiation intensity data collected in the target area; The first calculation module is used to calculate the average state of the solar radiation intensity evolving with the preset time interval within the preset time period as a reference sequence; The second data collection module is used to collect the solar radiation intensity of the target day as a first sequence according to a preset time interval; A second calculation module is used to calculate the first probability distribution function of the reference sequence and the second probability distribution functions of the multiple first sequences, and respectively calculate the Wasserstein distance between the first probability distribution function and each second probability distribution function, and determine the solar radiation stability of the corresponding day according to the Wasserstein distance; The first calculation module is configured to calculate the average state of the solar radiation intensity evolving with the preset time interval within the preset time period as follows: Among them, G ref (i) is the i-th solar radiation intensity in the reference sequence, G his (n, i) is the i-th solar radiation intensity on the n-th day in the historical solar radiation intensity data, and N is the number of days; The second calculation module is configured to calculate the probability distribution of the reference sequence with reference to the following formula: The probability distribution of the first sequence is calculated with reference to the following formula: in, is the probability of the i-th reference sequence value, is the probability of the ith first sequence value, and T is the number of records of solar radiation observations within the day.

4. The solar radiation stability evaluation device according to claim 3, characterized in that: The second calculation module is configured to calculate the Wasserstein distance between two probability distribution functions, specifically referring to the following formula: Wherein, the first probability distribution of the reference sequence and the second probability distribution of the first sequence are μ and v respectively, π∈Π(μ, v) is the set of all possible joint distributions of the first probability distribution of the reference sequence and the second probability distribution of the first sequence, defined in Inf is the lower bound, which means taking the value with the minimum cost among all possible joint distributions, and p is the order of Wasserstein distance.

5. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the solar radiation stability evaluation method according to any one of claims 1 to 2 is implemented.

6. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the solar radiation stability evaluation method according to any one of claims 1 to 2 are implemented.

Images