A method and system for correcting floating offshore solar radiation measurement data

Abstract

The application discloses a kind of floating offshore solar radiation measurement data correction method and system, it includes the following steps: obtaining the pitch angle and roll angle of floating offshore solar radiation measurement system;Obtain the unit normal vector of the measuring plane pointing to the sky in the horizontal plane rectangular coordinate system;Calculate the angle between the measuring plane and the horizontal plane;Get horizontal plane solar zenith angle and azimuth angle;Construct the unit vector along the direction of sunlight incidence pointing to the sun;Correct the zenith angle;Calculate the horizontal plane scattered irradiance value;The horizontal plane total irradiance saved by floating offshore solar radiation measurement system is corrected, and the corrected horizontal plane total irradiance is obtained.The measurement data of the floating offshore solar radiation measurement system is corrected by the application, the measurement error caused by the inclination of the measurement platform caused by wind and wave is reduced, and more accurate measurement data is provided for the evaluation of offshore light resources and the planning of offshore photovoltaic power station.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar radiation measurement, and particularly relates to a floating type offshore solar radiation measurement data correction method and system. BACKGROUND

[0002] The construction of offshore photovoltaic power stations can save land resources on land, avoid land competition with agriculture, urban construction and other fields, release more space for other important uses, and thus realize the optimal utilization of land resources. The development of offshore photovoltaic power stations first needs to evaluate the offshore solar radiation resources. Since the fixed type measurement platform on the sea has the disadvantages of difficult deployment, huge cost and insufficient flexibility, the movable floating type measurement platform is generally used for the measurement of solar radiation on the sea at present. However, due to the influence of wind and waves, there is an angle between the measurement plane of the floating type solar radiation measurement platform and the horizontal plane, and there is a difference between the measured radiation value and the horizontal plane radiation value, which leads to inaccurate solar resource evaluation. Therefore, it is of great significance to develop a movable offshore solar radiation measurement system for the development of offshore photovoltaic industry.

[0003] In the practical application of offshore photovoltaic measurement, the buoy type photometric device has the advantages of small construction cost and more flexible arrangement compared with the fixed type photometric device. According to GB / T37526-2019 "Solar Energy Evaluation Method", the solar energy resource data should include horizontal plane total radiation, and should include normal direct radiation, horizontal plane direct radiation, horizontal plane scattered radiation, sunshine duration and sunshine percentage. Generally, the pyranometer is arranged on a fixed base, the measurement plane is horizontal, and the measured total radiation value is the horizontal plane total radiation. However, since the base of the buoy type photometric device (floating type offshore solar radiation measurement system) is a buoy, the measurement plane of the buoy type photometric device is no longer coincident with the horizontal plane under the influence of the sea wave, and the total radiation value measured by the pyranometer is no longer the horizontal plane total radiation value, but only the total radiation value of the measurement plane of the pyranometer. Since there is an angle between the measurement plane and the horizontal plane, the incident angles of sunlight on the two planes are different, which leads to different components of sunlight on the two planes. On the other hand, there is reflected radiation on the sea surface, and when the measurement plane and the horizontal plane are no longer coincident, the total radiation value measured by the pyranometer includes the part of the sea surface reflected radiation. Therefore, under the action of the sea wave, the total radiation value directly measured by the buoy type photometric device is different from the horizontal plane total radiation value, which does not meet the data requirements described in GB / T37526-2019 "Solar Energy Evaluation Method". Therefore, it is necessary to correct the directly measured value of the buoy type photometric device to obtain the corresponding horizontal plane total radiation value.

[0004] In the prior art, the scattered radiation (DIF) measured by the inclined plane is assumed to be the same as the scattered radiation of the horizontal plane, and the total radiation (GHI) measurement value is corrected according to the solar elevation angle and the angle between the normal line of the inclined plane and the solar incident direction.

[0005] For the horizontal plane: GHI = DIF + DNI * cos θ0

[0006] For the inclined plane: GHI' = DIF' + DNI' * cos θ T

[0007] Where θ0 is the solar zenith angle, θ T is the angle between the normal line of the inclined plane and the solar incident direction.

[0008] The prior art assumes the isotropy of diffuse radiation, assumes that the inclined plane DIF is the same as the horizontal plane DIF under moderate inclination, that is, DIF = DIF', and since DNI is the direct radiation accepted by the plane perpendicular to the solar incident direction, DNI = DNI'. The horizontal plane GHI can be obtained from the above equation

[0009] The prior art has the following disadvantages:

[0010] (1) On the basis of the isotropy of diffuse radiation, it is considered that the diffuse radiation of the inclined plane and the horizontal plane is the same, which is proved to be effective when the angle between the inclined plane and the horizontal plane is less than 10°, but the influence of sea surface reflection on the measurement value of diffuse radiation when the angle between the inclined plane and the horizontal plane is greater than 10° is not considered;

[0011] (2) The influence of sea surface reflection on the measurement value of total radiation 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

[0013] In view of the above problems in the prior art, the floating type sea surface solar radiation measurement data correction method and system provided by the present application solves the problem that the prior art does not effectively correct the sea surface solar radiation measurement data when the wind and wave are large, resulting in large measurement error.

[0014] In order to achieve the above-mentioned purpose of the application, the technical scheme adopted by the present application is:

[0015] The present application provides a floating type sea surface solar radiation measurement data correction method, which comprises the following steps:

[0016] S1, establishing a rectangular coordinate system on the horizontal plane, obtaining the pitch angle and roll angle of the floating type sea surface solar radiation measurement system;

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

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

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

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

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

[0022] S7, taking an average value of the horizontal plane scattered irradiance corresponding to the angle between the measurement plane and the horizontal plane being less than or equal to a set angle value in a measurement period of the floating offshore solar radiation measurement system as a horizontal plane scattered irradiance value of the measurement period;

[0023] S8, in each measurement period of the floating offshore solar radiation measurement system, correcting a horizontal plane total irradiance saved by the floating offshore solar radiation measurement system at the measurement time t according to the horizontal plane scattered irradiance value of the measurement period, the latitude and the longitude of the floating offshore solar radiation measurement system, 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, to obtain a corrected horizontal plane total irradiance at the measurement time t, and further to obtain a corrected horizontal plane total irradiance in the entire measurement period.

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

[0025]

[0026] wherein is the unit normal vector of the measurement 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 a sine function; and cos is a cosine function.

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

[0028]

[0029] where γ is the angle between the measurement plane and the horizontal plane; is the horizontal plane upward normal vector in the horizontal plane orthogonal coordinate system; is the module of is the module of [.] T denotes the transpose of a matrix.

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

[0031]

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

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

[0034]

[0035] where θ′ z is the corrected zenith angle; is the module of

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

[0037]

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

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

[0040] ​​

[0041] GHI = GHI' + DIF' * albedo wherein GHI is the corrected horizontal total irradiance at the measurement time t; GHI' is the horizontal total irradiance saved by the floating offshore solar radiation measurement system at the measurement time t; DIF' is the horizontal diffuse irradiance measured by the floating offshore solar radiation measurement system at the measurement time t; and albedo is the reflectivity of the sea surface.

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

[0043] a first angle data obtaining module configured to establish a horizontal rectangular coordinate system and obtain a pitch angle and a roll angle of the floating offshore solar radiation measurement system;

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

[0045] a two-plane included angle calculating module configured to calculate an included angle between the measurement plane and the horizontal plane according to an included angle between the unit normal vector of the measurement plane pointing to the sky in the horizontal rectangular coordinate system and a horizontal upward normal vector in the horizontal rectangular coordinate system;

[0046] a second angle data obtaining module configured to obtain a horizontal solar zenith angle and a horizontal solar azimuth angle corresponding to the latitude and the longitude of the floating offshore solar radiation measurement system and a measurement time t according to the latitude and the longitude and the measurement time t;

[0047] a unit vector constructing module configured to construct a unit vector pointing to the sun along a solar light incident direction in the horizontal rectangular coordinate system according to the horizontal solar zenith angle and the horizontal solar azimuth angle obtained by the second angle data obtaining module;

[0048] a zenith angle correcting module configured to correct the zenith angle according to the unit normal vector of the measurement plane pointing to the sky in the horizontal rectangular coordinate system and the unit vector pointing to the sun along the solar light incident direction, to obtain a corrected zenith angle corresponding to the measurement time t;

[0049] a horizontal diffuse irradiance value calculating module configured to take an average value of the horizontal diffuse irradiance corresponding to a measurement period in which an included angle between the measurement plane and the horizontal plane is less than or equal to a set included angle value as a horizontal diffuse irradiance value of the measurement period;

[0050] The horizontal plane total irradiance correction module is used for correcting the horizontal plane total irradiance saved by the floating offshore solar radiation measuring system at the measuring moment t according to the horizontal plane scattering irradiance value of each measuring period of the floating offshore solar radiation measuring system, the latitude and longitude of the floating offshore solar radiation measuring system and the horizontal plane solar zenith angle corresponding to the measuring moment t, the corrected zenith angle corresponding to the measuring moment t, the reflectivity of the sea surface, the angle between the measuring plane and the horizontal plane, and the horizontal plane scattering irradiance measured at the measuring moment t, so as to obtain the corrected horizontal plane total irradiance at the measuring moment t, and then obtain the corrected horizontal plane total irradiance in the whole measuring period.

[0051] An electronic device is provided, including a processor and a memory for storing processor-executable instructions, the processor implementing a method for correcting floating offshore solar radiation measurement data when executing the instructions.

[0052] A computer-readable storage medium is provided, having computer instructions stored thereon, the instructions implementing a method for correcting floating offshore solar radiation measurement data when executed.

[0053] The present application has the advantages that the present application effectively corrects the solar radiation measurement error caused by waves on the basis of measuring the real-time tilt angle of the measuring plane, obtains the horizontal plane solar radiation value of the sea surface, and improves the accuracy of offshore solar radiation resource evaluation. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 It is a flowchart of the present method;

[0055] Figure 2 It is a scene diagram in the embodiment;

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

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

[0058] Figure 5 It is the RMSE value between the floating platform GHI measurement value and the terrestrial GHI measurement value before and after correction by the present method calculated on a monthly basis;

[0059] Figure 6 It is the RMSE value between the floating platform GHI measurement value and the terrestrial GHI measurement value before and after correction by the present method calculated on a daily basis. DETAILED DESCRIPTION

[0060] The specific embodiments of the present application are described below to enable those skilled in the art to understand the present application, but it should be clear that the present application is not limited to the scope of the specific embodiments, and for those skilled in the art, it is obvious that various changes are within the spirit and scope of the present application defined and determined by the appended claims, and all the inventions utilizing the concept of the present application are within the scope of protection.

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

[0062] S1, a rectangular coordinate system is established on the horizontal plane, and the pitch angle and the roll angle of the floating offshore solar radiation measurement system are obtained;

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

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

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

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

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

[0068] S7, the average value of the horizontal plane scattered irradiance corresponding to the angle between the measurement plane and the horizontal plane being less than or equal to the set angle value in a measurement period is taken as the horizontal plane scattered irradiance value of the measurement period;

[0069] ​S8, in each measurement period of the floating offshore solar radiation measurement system, according to the horizontal plane scattering irradiance value of the measurement period, the longitude and latitude of the floating offshore solar radiation measurement system, 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, the horizontal plane scattering 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 whole measurement period is obtained.

[0070] When establishing a rectangular coordinate system on the horizontal plane, the embodiment takes the east-west direction as the x-axis, east as positive; takes the south-north direction as the y-axis, north as positive; takes the direction perpendicular to the horizontal plane as the z-axis, upward as positive. The angle turned around the x-axis measured by the attitude sensor in the floating offshore solar radiation measurement system is the pitch angle a, and the angle turned clockwise along the x-axis is positive; the angle turned around the y-axis is the roll angle b, and the angle turned counterclockwise along the y-axis 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] Wherein is the unit normal vector of the measurement plane pointing to the sky in the horizontal plane rectangular coordinate system; a is the pitch angle of the floating offshore solar radiation measurement system; b 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 measurement plane and the horizontal plane in step S3 is:

[0074]

[0075] Wherein g is the angle between the measurement plane and the horizontal plane; is the upward normal vector of the horizontal plane in the horizontal plane rectangular coordinate system; is the module of is the module of . T Indicates the transpose of the matrix.

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

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

[0078] ​

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

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

[0081]

[0082] wherein θ' z is the corrected zenith angle, i.e. the angle between the direction of the sun's incident light and the normal of the measuring plane; is the modulus of .

[0083] The expression for calculating the horizontal plane diffuse irradiance value of one measuring period in step S7 is:

[0084]

[0085] wherein DIF represents the horizontal plane diffuse irradiance value of one measuring period; N is the number of horizontal plane diffuse irradiance measurements of the floating offshore solar radiation measuring system within one measuring period when the angle between the measuring plane and the horizontal plane is less than or equal to the set angle value δ; DIF' γ≤δ,n is the nth horizontal plane diffuse irradiance measurement result of the floating offshore solar radiation measuring system within one measuring period when the angle between the measuring plane and the horizontal plane is less than or equal to the set angle value δ.

[0086] The expression for obtaining the corrected horizontal plane total irradiance at the measuring time t in step S8 is:

[0087]

[0088] wherein GHI is the corrected horizontal plane total irradiance at the measuring time t; GHI' is the horizontal plane total irradiance saved by the floating offshore solar radiation measuring system at the measuring time t; DIF' is the horizontal plane diffuse irradiance measured by the floating offshore solar radiation measuring system at the measuring time t; albedo is the reflectivity of the sea surface.

[0089] In the calculation process of the corrected horizontal plane total irradiance at the measuring time t, cosθ' z = | -sinθ z sinθ A sinβ - sinθ z cosθ A sinαcosβ + cosθ z cosαcosβ |, cosγ = |cosα*cosβ |.

[0090] In the specific implementation process, the application also provides a system of a correction method based on floating offshore solar radiation measurement data, which comprises:

[0091] A first angle data acquisition module is configured to establish a rectangular coordinate system on a horizontal plane, and acquire a pitch angle and a roll angle of the floating offshore solar radiation measurement system.

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

[0093] A two-plane included angle calculation module is configured to calculate an included angle between the measurement plane and the horizontal plane according to an included angle between the unit normal vector of the measurement plane pointing to the sky in the rectangular coordinate system on the horizontal plane and a horizontal upward normal vector in the rectangular coordinate system on the horizontal plane.

[0094] A second angle data acquisition module is configured to acquire a horizontal plane solar zenith angle and an azimuth angle corresponding to the latitude and the longitude of the floating offshore solar radiation measurement system and a measurement time t according to the latitude and the longitude and the measurement time t.

[0095] A unit vector construction module is configured to construct a unit vector pointing to the sun along a solar light incident direction in the rectangular coordinate system on the horizontal plane according to the horizontal plane solar zenith angle and the azimuth angle obtained by the second angle data acquisition module.

[0096] A zenith angle correction module is configured to correct a zenith angle according to the unit normal vector of the measurement plane pointing to the sky in the rectangular coordinate system on the horizontal plane and the unit vector pointing to the sun along the solar light incident direction, and obtain a corrected zenith angle corresponding to the measurement time t.

[0097] A horizontal plane scattered irradiance value calculation module is configured to take an average value of the horizontal plane scattered irradiance corresponding to a measurement period in which an included angle between the measurement plane and the horizontal plane is less than or equal to a set included angle value as a horizontal plane scattered irradiance value of the measurement period.

[0098] A horizontal plane total irradiance correction module is configured to correct a horizontal plane total irradiance saved by the floating offshore solar radiation measurement system at a measurement time t according to the horizontal plane scattered irradiance value of a measurement period, the latitude and the longitude of the floating offshore solar radiation measurement system, the horizontal plane solar zenith angle corresponding to the measurement time t, the corrected zenith angle corresponding to the measurement time t, a reflectivity of a sea surface, the included 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 a corrected horizontal plane total irradiance at the measurement time t, and further obtain a corrected horizontal plane total irradiance in the entire measurement period.

[0099] An electronic device is provided, including a processor and a memory for storing processor-executable instructions, wherein the processor executes the instructions to implement a method for correcting floating marine solar radiation measurement data.

[0100] A computer-readable storage medium is provided having computer instructions stored thereon, which, when executed, implement a method for correcting floating marine solar radiation measurement data.

[0101] In one embodiment of the present invention, the algorithm proposed in this invention was verified at a near-shore experimental site. For example... Figure 2 As shown, the floating marine solar radiation measurement system is fixed at a distance of about 100m from the shore by mooring, while a solar radiometer is placed horizontally on the shore for measurement. The onshore measurement data is used to verify the accuracy of the correction method proposed in this invention.

[0102] In this experiment, a MEMS attitude sensor was installed on the floating marine solar radiation measurement system, achieving a millisecond-level response speed. The SPN1 thermopile solar radiometer used had a sampling frequency of 1 Hz, and the measured elements were total horizontal radiation (GHI) and diffuse horizontal radiation (DIF). The radiation data was saved hourly. In actual operation, for each measurement time t, the pitch angle, roll angle, and scattered radiation DIF′ measured by SPN1 of the floating marine solar radiation measurement system at that time 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, total radiation GHI′ and scattered radiation DIF′ measured by SPN1 of the floating marine solar radiation measurement system at that time are recorded, and the angle between the measurement platform and the horizontal plane, the solar zenith angle, and the angle between the sun and the measurement plane at that time are calculated. For each data storage time T, the DIF′ values ​​of all measurement platforms with angles less than 10° to the horizontal plane within the previous ten minutes are taken and averaged to obtain the scattered horizontal radiation DIF value at data storage time T. The required quantities are then substituted into this method to calculate the total horizontal radiation value GHI at data storage time T, where the water surface reflectivity is set to 0.1.

[0103] A comparative analysis was conducted on one year's data from a floating marine solar radiation measurement system and land-based measurements to evaluate the correction effect of this invention on radiation measurement values. For hourly GHI data throughout the year, the RMSE (root mean square error) of the hourly GHI value sequence obtained from the floating platform before correction and the corresponding hourly GHI measurement value sequence from land was 17.6 W / (m^2). After correction using this method, the RMSE value was 1.156 W / (m^2), representing an overall error reduction of 93%. Figure 3The absolute value (AE) of the hourly error before and after correction using the method is analyzed, and the results show that the accuracy of the data obtained by the floating offshore solar radiation measurement system is significantly improved after using the method.

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

[0105] Figure 5 The RMSE values between the floating platform GHI measurement values and the land GHI measurement values before and after correction using the method are calculated on a monthly basis. As shown in Figure 5 , the method shows significant correction effect in each month after correction.

[0106] Figure 6 The RMSE values between the floating platform GHI measurement values and the land GHI measurement values before and after correction using the method are calculated on a daily basis. As shown in Figure 6 , the method shows significant correction effect in each day after correction.

[0107] In summary, the present application corrects the measurement data of the floating offshore solar radiation measurement system, reduces the measurement error caused by the inclination of the measurement platform caused by wind and waves, 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 of correcting floating offshore solar radiation measurement data, characterized by, The method comprises the following steps: S1, establishing a rectangular coordinate system on a horizontal plane, and obtaining a pitch angle and a roll angle of the floating offshore solar radiation measuring system; S2, obtaining a unit normal vector of a measuring plane pointing to the sky in the horizontal plane rectangular coordinate system according to the pitch angle and the roll angle of the floating offshore solar radiation measuring system; S3, calculating an angle between the measuring plane and the horizontal plane according to an angle between the unit normal vector of the measuring plane pointing to the sky in the horizontal plane rectangular coordinate system and a horizontal plane upward normal vector in the horizontal plane rectangular coordinate system; S4, obtaining a horizontal plane solar zenith angle and an azimuth angle corresponding to the latitude and the longitude of the floating offshore solar radiation measuring system and a measurement time t according to the latitude and the longitude and the measurement time t; S5, constructing a unit vector pointing to the sun along a solar light incident direction in the horizontal plane rectangular coordinate system according to the horizontal plane solar zenith angle and the azimuth angle obtained in step S4 corresponding to the measurement time t; S6, correcting the zenith angle according to the unit normal vector of the measuring plane pointing to the sky in the horizontal plane rectangular coordinate system and the unit vector pointing to the sun along the solar light incident direction, to obtain a corrected zenith angle corresponding to the measurement time t; S7, taking an average value of the horizontal plane scattered irradiance corresponding to a condition that the angle between the measuring plane and the horizontal plane of the floating offshore solar radiation measuring system is less than or equal to a set angle value in a measurement period as a horizontal plane scattered irradiance value of the measurement period; S8, in each measurement period of the floating offshore solar radiation measuring system, correcting a horizontal plane total irradiance saved by the floating offshore solar radiation measuring system at the measurement time t according to the horizontal plane scattered irradiance value of the measurement period, the horizontal plane solar zenith angle corresponding to the latitude and the longitude of the floating offshore solar radiation measuring system and the measurement time t, the corrected zenith angle corresponding to the measurement time t, a reflectivity of the sea surface, the angle between the measuring plane and the horizontal plane, and the horizontal plane scattered irradiance measured at the measurement time t, to obtain a corrected horizontal plane total irradiance at the measurement time t, and then to obtain the corrected horizontal plane total irradiance in the entire measurement period.

2. The method of claim 1, wherein In step S2, the expression of the plane unit normal vector in the horizontal plane rectangular coordinate system is: wherein is a unit normal vector of the measurement plane pointing to the sky in the horizontal plane rectangular coordinate system; a 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 a sine function; and cos is a cosine function.

3. The method of claim 2, wherein the method further comprises: In step S3, the calculation expression of the angle between the measuring plane and the horizontal plane is: where γ is the angle between the measurement plane and the horizontal plane; is the horizontal plane upward normal vector in the horizontal plane rectangular coordinate system; is the horizontal plane upward normal vector in the horizontal plane rectangular coordinate system; the modulus of the modulus of the modulus of denotes the transpose of a matrix.

4. The method of claim 3, wherein the method further comprises: In step S5, the expression of the unit vector pointing to the sun along the solar light incident direction is: wherein is the unit vector pointing towards the sun along the direction of the sun's incident light; θ A is the horizontal solar azimuth angle; θ z is the horizontal solar zenith angle.

5. The method of claim 4, wherein the method further comprises: In step S6, the expression of the corrected zenith angle is: where θ' z is the corrected zenith angle; is the module of.​ 6. The method of claim 5, wherein the method further comprises: In step S7, the calculation expression of the horizontal plane scattered irradiance value of the measurement period is: wherein DIF represents the horizontal plane scattering irradiance value of a measurement period; N is the number of horizontal plane scattering irradiance measurements corresponding to the floating offshore solar radiation measurement system measuring a plane angle with the horizontal plane less than or equal to a set angle value δ within a measurement period; DIF' γ≤δ,n is the nth horizontal plane scattering irradiance measurement result of the floating offshore solar radiation measurement system measuring a plane angle with the horizontal plane less than or equal to a set angle value δ within a measurement period.

7. The method of claim 6, wherein the method further comprises: In step S8, the expression of the corrected horizontal plane total irradiance at the measurement time t is: Wherein GHI is the corrected horizontal plane total irradiance at the measurement time t; GHI' is the horizontal plane total irradiance saved by the floating offshore solar radiation measuring system at the measurement time t; DIF' is the horizontal plane scattered irradiance measured by the floating offshore solar radiation measuring system at the measurement time t; albedo is the reflectivity of the sea surface.

8. A system for correcting data of solar radiation measurements at sea based on a method according to any one of claims 1 to 7, characterized in that, The method comprises: a first angle data acquisition module, configured to establish a rectangular coordinate system on a horizontal plane, and obtain a pitch angle and a roll angle of the floating offshore solar radiation measuring system; A unit normal vector obtaining module is configured to obtain a unit normal vector of a measurement plane pointing to the sky in a horizontal plane rectangular coordinate system according to a pitch angle and a roll angle of the floating offshore solar radiation measurement system. A two-plane included angle calculating module is configured to calculate a measurement plane and horizontal plane included angle according to an included angle between the unit normal vector of the measurement plane pointing to the sky in the horizontal plane rectangular coordinate system and a horizontal plane upward normal vector in the horizontal plane rectangular coordinate system. A second angle data obtaining module is configured to obtain a horizontal plane solar zenith angle and azimuth angle corresponding to the latitude and longitude and a measurement time t according to the latitude and longitude and the measurement time t of the floating offshore solar radiation measurement system. A unit vector constructing module is configured to construct a unit vector pointing to the sun along a solar light incident direction in the horizontal plane rectangular coordinate system according to the horizontal plane solar zenith angle and the azimuth angle obtained by the second angle data obtaining module corresponding to the measurement time t. A zenith angle correcting module is configured to correct the zenith angle according to the unit normal vector of the measurement plane pointing to the sky in the horizontal plane rectangular coordinate system and the unit vector pointing to the sun along the solar light incident direction, to obtain a corrected zenith angle corresponding to the measurement time t. A horizontal plane scattered irradiance value calculating module is configured to take an average value of the horizontal plane scattered irradiance corresponding to a measurement plane and horizontal plane included angle less than or equal to a set included angle value in a measurement period of the floating offshore solar radiation measurement system as a horizontal plane scattered irradiance value of the measurement period. A horizontal plane total irradiance correcting module is configured to correct the horizontal plane total irradiance saved by the floating offshore solar radiation measurement system at the measurement time t according to the horizontal plane scattered irradiance value of the measurement period, the latitude and longitude of the floating offshore solar radiation measurement system, 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 measurement plane and horizontal plane included angle, and the horizontal plane scattered irradiance measured at the measurement time t in each measurement period of the floating offshore solar radiation measurement system, to obtain the corrected horizontal plane total irradiance at the measurement time t, and further obtain the corrected horizontal plane total irradiance in the entire measurement period.

9. An electronic device, comprising: The instructions are executed to implement the correction method of the floating offshore solar radiation measurement data according to any one of claims 1-7.

10. A computer readable storage medium having stored thereon computer instructions, wherein, The instructions are executed to implement the correction method of the floating offshore solar radiation measurement data according to any one of claims 1-7.

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