Method and system for correcting floating type offshore solar radiation measurement data

Abstract

The invention discloses a method and a system for correcting floating type seaborne solar radiation measurement data. The method comprises the following steps: acquiring a pitch angle and a roll angle of a floating type seaborne solar radiation measurement system; acquiring a unit normal vector of a measurement plane pointing to the sky in a horizontal plane rectangular coordinate system; calculating the included angle between the measuring plane and the horizontal plane; acquiring a solar zenith angle and an azimuth angle of a horizontal plane; constructing a unit vector pointing to the sun along the incident direction of the sunlight; correcting the zenith angle; calculating a horizontal plane scattering irradiance value; and correcting the total irradiance of the horizontal plane stored by the floating type offshore solar radiation measurement system to obtain the corrected total irradiance of the horizontal plane. The measurement data of the floating type offshore solar radiation measurement system is corrected, so that the measurement error caused by the inclination angle of the measurement platform due to stormy waves is reduced, and more accurate measurement data is provided for evaluation of offshore light resources and planning of an offshore photovoltaic power station.

Description

Technical Field

[0001] The present invention relates to the technical field of solar radiation measurement, and in particular to a method and system for correcting floating offshore solar radiation measurement data. Background Art

[0002] The construction of offshore photovoltaic power stations can save land resources on land, avoid land competition with agriculture, urban construction and other fields, and release more space for other important uses, thereby achieving the optimal use of land resources. The development of offshore photovoltaics first requires an assessment of offshore solar radiation resources. Since fixed offshore measurement platforms have the disadvantages of being difficult to deploy, costly and inflexible, mobile floating measurement platforms are generally used for offshore solar radiation measurements. However, due to the influence of wind and waves, there is an angle between the measurement plane of the floating solar radiation measurement platform and the horizontal plane, and there is a difference between the measured radiation value and the horizontal plane radiation value, resulting in inaccurate solar resource assessment. Therefore, the development of a mobile offshore solar radiation measurement system is of great significance to the development of the offshore photovoltaic industry.

[0003] In the actual application of offshore photovoltaic measurement, the buoy photometer has the advantages of low construction cost and more flexible layout compared to the fixed photometer. According to GB / T37526-2019 "Solar Energy Assessment Method", solar energy resource data should include total horizontal radiation, which should include normal direct radiation, horizontal direct radiation, horizontal scattered radiation, sunshine hours, and sunshine percentage. Generally speaking, the optical radiometer is arranged on a fixed base, its measurement plane is a horizontal plane, and the measured total radiation value is the total horizontal radiation. However, since the base of the buoy photometer (floating offshore solar radiation measurement system) is a buoy, during the measurement process, the buoy photometer is affected by the turbulence of the waves, and the measurement plane no longer coincides with the horizontal plane. The total radiation value measured by the optical radiometer is no longer the total radiation value of the horizontal plane, but only the total radiation value of the optical radiometer measurement plane. Due to the angle between the measurement plane and the horizontal plane, the incident angles of sunlight on the two planes are different, resulting in different components of sunlight directly incident on the two planes; on the other hand, there is reflected radiation on the sea surface. When the measurement plane and the horizontal plane no longer coincide, the total radiation value measured by the optical radiometer includes part of the radiation reflected from the sea surface. Therefore, under the action of waves, the total radiation value directly measured by the buoy photometer is different from the total radiation value on the horizontal plane, and does not meet the data requirements described in GB / T37526-2019 "Solar Energy Assessment Method". It is necessary to correct the direct measurement value of the buoy photometer to obtain the corresponding algorithm for the total radiation value on the horizontal plane.

[0004] In the prior art, it is assumed that the scattered radiation (DIF) measured by the inclined plane is the same as the scattered radiation of the horizontal plane, and the global radiation (GHI) measurement value is corrected according to the solar altitude angle and the angle between the normal of the inclined plane and the solar incidence direction.

[0005] For the horizontal plane: GHI=DIF+DNI*cosθ 0

[0006] For inclined surface: GHI′=DIF′+DNI′*cosθ T

[0007] where θ 0 is the solar zenith angle, θ T is the angle between the normal of the inclined plane and the direction of solar incidence.

[0008] Prior art 1 Based on the isotropy of diffuse radiation, it is assumed that under moderate inclination, the inclined plane DIF is the same as the horizontal plane DIF, that is, DIF = DIF'; and since DNI is the direct radiation received by the plane perpendicular to the direction of solar incidence, DNI = DNI'. The horizontal plane GHI can be obtained from the above equation

[0009] This prior art has the following disadvantages:

[0010] (1) Based on the isotropy of diffuse radiation, it is assumed that the diffuse radiation of the inclined plane and the horizontal plane is the same. This assumption is proven to be valid when the angle between the inclined plane and the horizontal plane is less than 10°. However, it does not take into account the influence of sea surface reflection on the diffuse radiation measurement when the angle between the inclined plane and the horizontal plane is greater than 10°.

[0011] (2) The influence of sea surface reflection on the total radiation measurement value when the angle between the inclined plane and the horizontal plane is too large is not considered;

[0012] (3) No specific method is given to determine the angle between the inclined plane and the horizontal plane. Summary of the invention

[0013] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method and system for correcting floating offshore solar radiation measurement data, which solves the problem that the prior art fails to effectively correct offshore solar radiation measurement data when the wind and waves are large, resulting in large measurement errors.

[0014] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0015] A method for correcting floating offshore solar radiation measurement data is provided, which comprises the following steps:

[0016] S1. Establish a rectangular coordinate system on the horizontal plane to obtain the pitch angle and roll angle of the floating offshore solar radiation measurement system;

[0017] S2. Obtaining a unit normal vector of a measuring plane pointing to the sky in a horizontal rectangular coordinate system according to a pitch angle and a roll angle of the floating offshore solar radiation measurement system;

[0018] S3, calculating the angle between the measuring plane and the horizontal plane according to the angle between the unit normal vector of the measuring plane pointing to the sky in the horizontal plane rectangular coordinate system and the upward normal vector of the horizontal plane in the horizontal plane rectangular coordinate system;

[0019] S4. According to the longitude and latitude of the floating offshore solar radiation measurement system and the measurement time t, obtain the horizontal plane solar zenith angle and azimuth angle corresponding to the longitude and latitude and the measurement time t;

[0020] S5, constructing a unit vector pointing to the sun along the incident direction of sunlight corresponding to the measurement time t in the horizontal plane rectangular coordinate system according to the horizontal plane solar zenith angle and azimuth angle obtained in step S4;

[0021] S6, correcting the zenith angle according to the unit normal vector of the measuring plane pointing to the sky and the unit vector pointing to the sun along the incident direction of sunlight in the horizontal plane rectangular coordinate system, to obtain a corrected zenith angle corresponding to the measuring time t;

[0022] S7, taking the average value of the horizontal scattered irradiance corresponding to the angle between the measuring plane and the horizontal plane of the floating offshore solar radiation measurement system within a measurement cycle when the angle is less than or equal to the set angle value as the horizontal scattered irradiance value of the measurement cycle;

[0023] S8. In each measurement cycle of the floating offshore solar radiation measurement system, according to the horizontal plane scattered irradiance value of the measurement cycle, the longitude and latitude of the floating offshore solar radiation measurement system and the horizontal plane solar zenith angle corresponding to the measurement time t, the corrected zenith angle corresponding to the measurement time t, the reflectivity of the sea surface, the angle between the measurement plane and the horizontal plane, and the horizontal plane scattered irradiance measured at the measurement time t, the horizontal plane total irradiance saved by the floating offshore solar radiation measurement system at the measurement time t is corrected to obtain the corrected horizontal plane total irradiance at the measurement time t, and then the corrected horizontal plane total irradiance in the entire measurement cycle is obtained.

[0024] Furthermore, the expression of the plane unit normal vector in the horizontal plane rectangular coordinate system in step S2 is:

[0025]

[0026] in is the unit normal vector of the measuring plane pointing to the sky in the horizontal rectangular coordinate system; α is the pitch angle of the floating offshore solar radiation measurement system; β is the roll angle of the floating offshore solar radiation measurement system; sin is the sine function; cos is the cosine function.

[0027] Furthermore, the calculation expression of the angle between the measuring plane and the horizontal plane in step S3 is:

[0028]

[0029] Where γ is the angle between the measuring plane and the horizontal plane; is the upward normal vector of the horizontal plane in the horizontal rectangular coordinate system; for Model; for Model;[.] T Represents the transpose of a matrix.

[0030] Furthermore, the expression of the unit vector pointing to the sun along the incident direction of sunlight in step S5 is:

[0031]

[0032] in is the unit vector pointing to the sun along the incident direction of sunlight; θ A is the horizontal solar azimuth; θ z is the solar zenith angle in the horizontal plane.

[0033] Furthermore, the expression of the corrected zenith angle in step S6 is:

[0034]

[0035] where θ′ z is the corrected zenith angle; for Model.

[0036] Furthermore, the calculation expression of the horizontal plane scattered irradiance value of one measurement cycle in step S7 is:

[0037]

[0038] Where DIF represents the horizontal scattered irradiance value of a measurement cycle; N is the number of horizontal scattered irradiance measurements corresponding to the angle between the measurement plane and the horizontal plane of the floating offshore solar radiation measurement system within a measurement cycle when the angle is less than or equal to the set angle value δ; DIF′ γ≤δ,n It is the scattered irradiance measurement result of the nth horizontal plane when the angle between the measuring plane and the horizontal plane is less than or equal to the set angle value δ within one measurement cycle of the floating offshore solar radiation measurement system.

[0039] Furthermore, the expression of the total horizontal plane irradiance at the corrected measurement time t obtained in step S8 is:

[0040]

[0041] Where GHI is the corrected total horizontal plane irradiance at the measurement time t; GHI′ is the total horizontal plane irradiance saved by the floating offshore solar radiation measurement system at the measurement time t; DIF′ is the horizontal plane scattered irradiance measured by the floating offshore solar radiation measurement system at the measurement time t; albedo is the reflectivity of the sea surface.

[0042] A system based on a method for correcting floating offshore solar radiation measurement data is provided, comprising:

[0043] The first angle data acquisition module is used to establish a rectangular coordinate system on the horizontal plane to obtain the pitch angle and roll angle of the floating offshore solar radiation measurement system;

[0044] A unit normal vector acquisition module is used to obtain a unit normal vector of a measuring plane pointing to the sky in a horizontal rectangular coordinate system according to a pitch angle and a roll angle of the floating offshore solar radiation measurement system;

[0045] A two-plane angle calculation module is used to calculate the angle between the measuring plane and the horizontal plane according to the angle between the unit normal vector of the measuring plane pointing to the sky in the horizontal plane rectangular coordinate system and the upward normal vector of the horizontal plane in the horizontal plane rectangular coordinate system;

[0046] The second angle data acquisition module is used to acquire the horizontal plane solar zenith angle and azimuth angle corresponding to the longitude and latitude and the measurement time t of the floating offshore solar radiation measurement system;

[0047] A unit vector construction module, used to construct a unit vector pointing to the sun along the incident direction of sunlight corresponding to the measurement time t in a horizontal plane rectangular coordinate system according to the horizontal plane solar zenith angle and azimuth angle obtained by the second angle data acquisition module;

[0048] The zenith angle correction module is used to correct the zenith angle according to the unit normal vector of the measuring plane pointing to the sky and the unit vector pointing to the sun along the incident direction of sunlight in the horizontal plane rectangular coordinate system, so as to obtain the corrected zenith angle corresponding to the measuring time t;

[0049] The horizontal scattered irradiance value calculation module is used to take the average value of the horizontal scattered irradiance corresponding to the angle between the measuring plane and the horizontal plane of the floating offshore solar radiation measurement system within a measurement cycle as the horizontal scattered irradiance value of the measurement cycle;

[0050] The horizontal plane total irradiance correction module is used to correct the horizontal plane total irradiance saved by the floating offshore solar radiation measurement system at the measurement time t in each measurement cycle of the floating offshore solar radiation measurement system according to the horizontal plane scattered irradiance value of the measurement cycle, the longitude and latitude of the floating offshore solar radiation measurement system and the horizontal plane solar zenith angle corresponding to the measurement time t, the corrected zenith angle corresponding to the measurement time t, the reflectivity of the sea surface, the angle between the measurement plane and the horizontal plane, and the horizontal plane scattered irradiance measured at the measurement time t, so as to obtain the corrected horizontal plane total irradiance at the measurement time t, and then obtain the corrected horizontal plane total irradiance in the entire measurement cycle.

[0051] An electronic device is provided, comprising a processor and a memory for storing instructions executable by the processor. When the processor executes the instructions, a method for correcting floating offshore solar radiation measurement data is implemented.

[0052] A computer-readable storage medium is provided, on which computer instructions are stored. When the instructions are executed, a method for correcting floating offshore solar radiation measurement data is implemented.

[0053] The beneficial effects of the present invention are as follows: on the basis of realizing the measurement of the real-time tilt angle of the measuring plane, the present invention effectively corrects the solar radiation measurement error caused by waves, obtains the solar radiation value of the sea surface, and improves the accuracy of the assessment of marine solar radiation resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a schematic diagram of the process of this method;

[0055] Figure 2 It is a schematic diagram of a scene in an embodiment;

[0056] Figure 3 is the absolute value of the hourly error before and after correction using the method in the embodiment;

[0057] Figure 4 A frequency histogram of hourly data corrected by the method in the embodiment;

[0058] Figure 5 is the RMSE value between the GHI measurements of the floating platform and the GHI measurements of the land before and after correction by this method calculated on a monthly basis;

[0059] Figure 6 The RMSE value between the GHI measurements of the floating platform and the GHI measurements of the land before and after correction by this method is calculated daily. DETAILED DESCRIPTION

[0060] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0061] like Figure 1 As shown, the correction method of the floating offshore solar radiation measurement data includes the following steps:

[0062] S1. Establish a rectangular coordinate system on the horizontal plane to obtain the pitch angle and roll angle of the floating offshore solar radiation measurement system;

[0063] S2. Obtaining a unit normal vector of a measuring plane pointing to the sky in a horizontal rectangular coordinate system according to a pitch angle and a roll angle of the floating offshore solar radiation measurement system;

[0064] S3, calculating the angle between the measuring plane and the horizontal plane according to the angle between the unit normal vector of the measuring plane pointing to the sky in the horizontal plane rectangular coordinate system and the upward normal vector of the horizontal plane in the horizontal plane rectangular coordinate system;

[0065] S4. According to the longitude and latitude of the floating offshore solar radiation measurement system and the measurement time t, obtain the horizontal plane solar zenith angle and azimuth angle corresponding to the longitude and latitude and the measurement time t;

[0066] S5, constructing a unit vector pointing to the sun along the incident direction of sunlight corresponding to the measurement time t in the horizontal plane rectangular coordinate system according to the horizontal plane solar zenith angle and azimuth angle obtained in step S4;

[0067] S6, correcting the zenith angle according to the unit normal vector of the measuring plane pointing to the sky and the unit vector pointing to the sun along the incident direction of sunlight in the horizontal plane rectangular coordinate system, to obtain a corrected zenith angle corresponding to the measuring time t;

[0068] S7, taking the average value of the horizontal scattered irradiance corresponding to the angle between the measuring plane and the horizontal plane of the floating offshore solar radiation measurement system within a measurement cycle when the angle is less than or equal to the set angle value as the horizontal scattered irradiance value of the measurement cycle;

[0069] S8. In each measurement cycle of the floating offshore solar radiation measurement system, according to the horizontal plane scattered irradiance value of the measurement cycle, the longitude and latitude of the floating offshore solar radiation measurement system and the horizontal plane solar zenith angle corresponding to the measurement time t, the corrected zenith angle corresponding to the measurement time t, the reflectivity of the sea surface, the angle between the measurement plane and the horizontal plane, and the horizontal plane scattered irradiance measured at the measurement time t, the horizontal plane total irradiance saved by the floating offshore solar radiation measurement system at the measurement time t is corrected to obtain the corrected horizontal plane total irradiance at the measurement time t, and then the corrected horizontal plane total irradiance in the entire measurement cycle is obtained.

[0070] When establishing a rectangular coordinate system on the horizontal plane, this embodiment uses the east-west direction as the x-axis, with the east being positive; the north-south direction as the y-axis, with the north being positive; and the direction perpendicular to the horizontal plane as the z-axis, with the upward direction being positive. The angle rotated around the x-axis measured by the attitude sensor in the floating offshore solar radiation measurement system is the pitch angle α. When observed along the x-axis, the clockwise angle is positive; the angle rotated around the y-axis is the roll angle β. When observed along the y-axis, the counterclockwise angle is positive. On this basis, the expression of the plane unit normal vector in the horizontal plane rectangular coordinate system in step S2 is:

[0071]

[0072] in is the unit normal vector of the measuring plane pointing to the sky in the horizontal rectangular coordinate system; α is the pitch angle of the floating offshore solar radiation measurement system; β is the roll angle of the floating offshore solar radiation measurement system; sin is the sine function; cos is the cosine function.

[0073] The calculation expression of the angle between the measuring plane and the horizontal plane in step S3 is:

[0074]

[0075] Where γ is the angle between the measuring plane and the horizontal plane; is the upward normal vector of the horizontal plane in the horizontal rectangular coordinate system; for Model; for Model;[.] T Represents the transpose of a matrix.

[0076] In step S4, the horizontal solar zenith angle and azimuth angle corresponding to the longitude and latitude and the measurement time t are obtained in a clockwise increasing manner, with due north as 0.

[0077] The expression of the unit vector pointing to the sun along the incident direction of sunlight in step S5 is:

[0078]

[0079] in is the unit vector pointing to the sun along the incident direction of sunlight; θ A is the horizontal solar azimuth; θ z is the solar zenith angle in the horizontal plane.

[0080] The expression of the corrected zenith angle in step S6 is:

[0081]

[0082] where θ′ z is the corrected zenith angle, i.e. the angle between the sun’s incident direction and the normal of the measurement plane; for Model.

[0083] The calculation expression of the horizontal plane scattered irradiance value in one measurement cycle in step S7 is:

[0084]

[0085] Where DIF represents the horizontal scattered irradiance value of a measurement cycle; N is the number of horizontal scattered irradiance measurements corresponding to the angle between the measurement plane and the horizontal plane of the floating offshore solar radiation measurement system within a measurement cycle when the angle is less than or equal to the set angle value δ; DIF′ γ≤δ,n It is the scattered irradiance measurement result of the nth horizontal plane when the angle between the measuring plane and the horizontal plane is less than or equal to the set angle value δ within one measurement cycle of the floating offshore solar radiation measurement system.

[0086] The expression of the total horizontal irradiance at the measurement time t after correction obtained in step S8 is:

[0087]

[0088] Where GHI is the corrected total horizontal plane irradiance at the measurement time t; GHI′ is the total horizontal plane irradiance saved by the floating offshore solar radiation measurement system at the measurement time t; DIF′ is the horizontal plane scattered irradiance measured by the floating offshore solar radiation measurement system at the measurement time t; albedo is the reflectivity of the sea surface.

[0089] In the calculation process of the total irradiance on the horizontal surface at the corrected measurement time t, cosθ′ z =|-sinθ z sinθ A sinβ-sinθ z cosθ A sinαcosβ+cosθ z cosαcosβ|, cosγ=|cosα*cosβ|.

[0090] In a specific implementation process, the present invention also provides a system based on a correction method for floating offshore solar radiation measurement data, which includes:

[0091] The first angle data acquisition module is used to establish a rectangular coordinate system on the horizontal plane to obtain the pitch angle and roll angle of the floating offshore solar radiation measurement system;

[0092] A unit normal vector acquisition module is used to obtain a unit normal vector of a measuring plane pointing to the sky in a horizontal rectangular coordinate system according to a pitch angle and a roll angle of the floating offshore solar radiation measurement system;

[0093] A two-plane angle calculation module is used to calculate the angle between the measuring plane and the horizontal plane according to the angle between the unit normal vector of the measuring plane pointing to the sky in the horizontal plane rectangular coordinate system and the upward normal vector of the horizontal plane in the horizontal plane rectangular coordinate system;

[0094] The second angle data acquisition module is used to acquire the horizontal plane solar zenith angle and azimuth angle corresponding to the longitude and latitude and the measurement time t of the floating offshore solar radiation measurement system;

[0095] A unit vector construction module, used to construct a unit vector pointing to the sun along the incident direction of sunlight corresponding to the measurement time t in a horizontal plane rectangular coordinate system according to the horizontal plane solar zenith angle and azimuth angle obtained by the second angle data acquisition module;

[0096] The zenith angle correction module is used to correct the zenith angle according to the unit normal vector of the measuring plane pointing to the sky and the unit vector pointing to the sun along the incident direction of sunlight in the horizontal plane rectangular coordinate system, so as to obtain the corrected zenith angle corresponding to the measuring time t;

[0097] The horizontal scattered irradiance value calculation module is used to take the average value of the horizontal scattered irradiance corresponding to the angle between the measuring plane and the horizontal plane of the floating offshore solar radiation measurement system within a measurement cycle as the horizontal scattered irradiance value of the measurement cycle;

[0098] The horizontal plane total irradiance correction module is used to correct the horizontal plane total irradiance saved by the floating offshore solar radiation measurement system at the measurement time t in each measurement cycle of the floating offshore solar radiation measurement system according to the horizontal plane scattered irradiance value of the measurement cycle, the longitude and latitude of the floating offshore solar radiation measurement system and the horizontal plane solar zenith angle corresponding to the measurement time t, the corrected zenith angle corresponding to the measurement time t, the reflectivity of the sea surface, the angle between the measurement plane and the horizontal plane, and the horizontal plane scattered irradiance measured at the measurement time t, so as to obtain the corrected horizontal plane total irradiance at the measurement time t, and then obtain the corrected horizontal plane total irradiance in the entire measurement cycle.

[0099] An electronic device is provided, comprising a processor and a memory for storing instructions executable by the processor. When the processor executes the instructions, a method for correcting floating offshore solar radiation measurement data is implemented.

[0100] A computer-readable storage medium is provided, on which computer instructions are stored. When the instructions are executed, a method for correcting floating offshore solar radiation measurement data is implemented.

[0101] In one embodiment of the present invention, the algorithm proposed by the present invention was verified in a certain offshore experimental site. Figure 2 As shown, the floating offshore solar radiation measurement system is fixed about 100m away from the shore by mooring, and a solar radiation meter is placed horizontally on the shore for measurement. The onshore measurement data is used to verify the accuracy of the correction method proposed in the present invention.

[0102] In this experiment, the floating offshore solar radiation measurement system is equipped with a MEMS attitude sensor, which can achieve a millisecond response speed. The sampling frequency of the SPN1 thermopile solar radiometer used is 1Hz, and the measured elements are the global horizontal radiation GHI and the scattered horizontal radiation DIF. The radiation data is saved every hour. In the actual operation process, for each measurement time t, the pitch angle, roll angle and scattered radiation DIF′ measured by SPN1 of the floating offshore solar radiation measurement system are recorded, and the angle between the measurement platform and the horizontal plane at that time is calculated; for each data storage time T, the pitch angle, roll angle and total radiation GHI′ and scattered radiation DIF′ measured by SPN1 of the floating offshore solar radiation measurement system are recorded, and the angle between the measurement platform and the horizontal plane, the solar zenith angle and the angle of the sun relative to the measurement plane at that time are calculated; for each data storage time T, the DIF′ values ​​when the angles between all measurement platforms and the horizontal plane in the previous ten minutes are less than 10° are taken and averaged to obtain the scattered horizontal radiation DIF value at the data storage time T, and the required amount is substituted into the method to calculate the total horizontal radiation value GHI at the data storage time T, where the water surface reflectivity is set to 0.1.

[0103] A comparative analysis of one year's data of the floating offshore solar radiation measurement system and land measurements was conducted to evaluate the correction effect of the present invention on the radiation measurement values. For the hourly GHI data for the whole year, the RMSE (root mean square error) between the GHI hourly value sequence measured by the floating platform before correction and the corresponding land GHI measurement value hourly sequence was 17.6W / (m^2), and the RMSE value after correction by the present method was 1.156W / (m^2), and the overall error was reduced by 93%. Figure 3The absolute value of the hourly error (AE) before and after correction using this method is shown in Figure 2. The analysis of AE also shows that the accuracy of the data obtained by the floating offshore solar radiation measurement system has been significantly improved after adopting this method.

[0104] like Figure 4 As shown in Figure 2, the frequency analysis also reached the same conclusion. After correction using this method, ignoring the night (radiation value is 0), except for the interval with low total radiation value, the distribution of GHI measurement values ​​of the floating offshore solar radiation measurement system in each interval is closer to the land GHI measurement value.

[0105] Figure 5 The RMSE between the GHI measurements of the floating platform and the GHI measurements of the land before and after correction using this method is calculated on a monthly basis. Figure 5 It can be seen that this method has shown significant correction effects in all months after correction.

[0106] Figure 6 The RMSE between the GHI measurements of the floating platform and the GHI measurements of the land before and after correction using this method is calculated daily. Figure 6 It can be seen that the correction effect of this method is significant on a daily basis.

[0107] In summary, the present invention reduces the measurement error caused by the inclination of the measurement platform caused by wind and waves by correcting the measurement data of the floating offshore solar radiation measurement system, and provides more accurate measurement data for the evaluation of offshore light resources and the planning of offshore photovoltaic power stations.

Claims

1. A method for correcting floating offshore solar radiation measurement data, characterized in that: The following steps are involved: S1. Establish a rectangular coordinate system on the horizontal plane to obtain the pitch angle and roll angle of the floating offshore solar radiation measurement system; S2. Obtaining a unit normal vector of a measuring plane pointing to the sky in a horizontal rectangular coordinate system according to a pitch angle and a roll angle of the floating offshore solar radiation measurement system; S3, calculating the angle between the measuring plane and the horizontal plane according to the angle between the unit normal vector of the measuring plane pointing to the sky in the horizontal plane rectangular coordinate system and the upward normal vector of the horizontal plane in the horizontal plane rectangular coordinate system; S4. According to the longitude and latitude of the floating offshore solar radiation measurement system and the measurement time t, obtain the horizontal plane solar zenith angle and azimuth angle corresponding to the longitude and latitude and the measurement time t; S5, constructing a unit vector pointing to the sun along the incident direction of sunlight corresponding to the measurement time t in the horizontal plane rectangular coordinate system according to the horizontal plane solar zenith angle and azimuth angle obtained in step S4; S6, correcting the zenith angle according to the unit normal vector of the measuring plane pointing to the sky and the unit vector pointing to the sun along the incident direction of sunlight in the horizontal plane rectangular coordinate system, to obtain a corrected zenith angle corresponding to the measuring time t; S7, taking the average value of the horizontal scattered irradiance corresponding to the angle between the measuring plane and the horizontal plane of the floating offshore solar radiation measurement system within a measurement cycle when the angle is less than or equal to the set angle value as the horizontal scattered irradiance value of the measurement cycle; S8. In each measurement cycle of the floating offshore solar radiation measurement system, according to the horizontal plane scattered irradiance value of the measurement cycle, the longitude and latitude of the floating offshore solar radiation measurement system and the horizontal plane solar zenith angle corresponding to the measurement time t, the corrected zenith angle corresponding to the measurement time t, the reflectivity of the sea surface, the angle between the measurement plane and the horizontal plane, and the horizontal plane scattered irradiance measured at the measurement time t, the horizontal plane total irradiance saved by the floating offshore solar radiation measurement system at the measurement time t is corrected to obtain the corrected horizontal plane total irradiance at the measurement time t, and then the corrected horizontal plane total irradiance in the entire measurement cycle is obtained.

2. A method for correcting floating offshore solar radiation measurement data according to claim 1, characterized in that: The expression of the plane unit normal vector in the horizontal plane rectangular coordinate system in step S2 is: in is the unit normal vector of the measuring plane pointing to the sky in the horizontal rectangular coordinate system; α is the pitch angle of the floating offshore solar radiation measurement system; β is the roll angle of the floating offshore solar radiation measurement system; sin is the sine function; cos is the cosine function.

3. A method for correcting floating offshore solar radiation measurement data according to claim 2, characterized in that: The calculation expression of the angle between the measuring plane and the horizontal plane in step S3 is: Where γ is the angle between the measuring plane and the horizontal plane; is the upward normal vector of the horizontal plane in the horizontal rectangular coordinate system; for Model; for Model; Represents the transpose of a matrix.

4. A method for correcting floating offshore solar radiation measurement data according to claim 3, characterized in that: The expression of the unit vector pointing to the sun along the incident direction of sunlight in step S5 is: in is the unit vector pointing to the sun along the incident direction of sunlight; θ A is the horizontal solar azimuth; θ z is the solar zenith angle in the horizontal plane.

5. A method for correcting floating offshore solar radiation measurement data according to claim 4, characterized in that: The expression of the corrected zenith angle in step S6 is: where θ′ z is the corrected zenith angle; for Model.

6. A method for correcting floating offshore solar radiation measurement data according to claim 5, characterized in that: The calculation expression of the horizontal plane scattered irradiance value in one measurement cycle in step S7 is: Where DIF represents the horizontal scattered irradiance value of a measurement cycle; N is the number of horizontal scattered irradiance measurements corresponding to the angle between the measurement plane and the horizontal plane of the floating offshore solar radiation measurement system within a measurement cycle when the angle is less than or equal to the set angle value δ; DIF′ γ≤δ,n It is the scattered irradiance measurement result of the nth horizontal plane when the angle between the measuring plane and the horizontal plane is less than or equal to the set angle value δ within one measurement cycle of the floating offshore solar radiation measurement system.

7. A method for correcting floating offshore solar radiation measurement data according to claim 6, characterized in that: The expression of the total horizontal irradiance at the measurement time t after correction obtained in step S8 is: Where GHI is the corrected total horizontal plane irradiance at the measurement time t; GHI′ is the total horizontal plane irradiance saved by the floating offshore solar radiation measurement system at the measurement time t; DIF′ is the horizontal plane scattered irradiance measured by the floating offshore solar radiation measurement system at the measurement time t; albedo is the reflectivity of the sea surface.

8. A system based on a method for correcting floating offshore solar radiation measurement data according to any one of claims 1 to 7, characterized in that: include: The first angle data acquisition module is used to establish a rectangular coordinate system on the horizontal plane to obtain the pitch angle and roll angle of the floating offshore solar radiation measurement system; A unit normal vector acquisition module is used to obtain a unit normal vector of a measuring plane pointing to the sky in a horizontal rectangular coordinate system according to a pitch angle and a roll angle of the floating offshore solar radiation measurement system; A two-plane angle calculation module is used to calculate the angle between the measuring plane and the horizontal plane according to the angle between the unit normal vector of the measuring plane pointing to the sky in the horizontal plane rectangular coordinate system and the upward normal vector of the horizontal plane in the horizontal plane rectangular coordinate system; The second angle data acquisition module is used to acquire the horizontal plane solar zenith angle and azimuth angle corresponding to the longitude and latitude and the measurement time t of the floating offshore solar radiation measurement system; A unit vector construction module, used to construct a unit vector pointing to the sun along the incident direction of sunlight corresponding to the measurement time t in a horizontal plane rectangular coordinate system according to the horizontal plane solar zenith angle and azimuth angle obtained by the second angle data acquisition module; The zenith angle correction module is used to correct the zenith angle according to the unit normal vector of the measuring plane pointing to the sky and the unit vector pointing to the sun along the incident direction of sunlight in the horizontal plane rectangular coordinate system, so as to obtain the corrected zenith angle corresponding to the measuring time t; The horizontal scattered irradiance value calculation module is used to take the average value of the horizontal scattered irradiance corresponding to the angle between the measuring plane and the horizontal plane of the floating offshore solar radiation measurement system within a measurement cycle as the horizontal scattered irradiance value of the measurement cycle; The horizontal plane total irradiance correction module is used to correct the horizontal plane total irradiance saved by the floating offshore solar radiation measurement system at the measurement time t in each measurement cycle of the floating offshore solar radiation measurement system according to the horizontal plane scattered irradiance value of the measurement cycle, the longitude and latitude of the floating offshore solar radiation measurement system and the horizontal plane solar zenith angle corresponding to the measurement time t, the corrected zenith angle corresponding to the measurement time t, the reflectivity of the sea surface, the angle between the measurement plane and the horizontal plane, and the horizontal plane scattered irradiance measured at the measurement time t, so as to obtain the corrected horizontal plane total irradiance at the measurement time t, and then obtain the corrected horizontal plane total irradiance in the entire measurement cycle.

9. An electronic device, characterized in that: The invention comprises a processor and a memory for storing instructions executable by the processor. When the processor executes the instructions, a method for correcting floating offshore solar radiation measurement data as described in any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having computer instructions stored thereon, characterized in that: When the instruction is executed, a method for correcting floating offshore solar radiation measurement data as described in any one of claims 1 to 7 is implemented.

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