Grid planning method for grid connection of photovoltaic power stations

Abstract

The present invention provides a grid planning method for grid connection of a photovoltaic power station, belonging to the technical field of grid operation and maintenance, and including steps such as historical estimation, preliminary planning, actual measurement, and re-planning. By first performing short-term actual measurement on the target photovoltaic power station, the present invention can directly measure the relationship curve between the light intensity and its actual power supply from the results after grid connection, and rely on this relationship curve to estimate the future all-day power supply distribution of the target photovoltaic power station according to weather forecast data. Then, according to the requirements of the grid, the power supply supplemented by the photovoltaic power station to the grid is pre-planned and adjusted, so that there can be more time for response, regulation, correction, and remedy, thereby avoiding installing complex electrical equipment on each photovoltaic power station for adjustment, which is beneficial to reducing the equipment costs of photovoltaic power generation and grid operation and maintenance, is also more convenient for the management of maintenance personnel, and is also beneficial to improving the safety and stability of grid operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of power grid operation and maintenance, and more specifically, relates to a power grid planning method for grid connection of a photovoltaic power station. Background Art

[0002] Grid connection of photovoltaic power generation means that the direct current generated by solar modules is converted into alternating current that meets the requirements of the commercial power grid through a grid-connected inverter and then directly connected to the public power grid. In recent years, with the development of photovoltaic technology and the encouragement of relevant policies, the construction of photovoltaic power stations has gradually increased, accounting for a relatively large proportion in the power supply of some regions.

[0003] Since the power supply of a photovoltaic power station is greatly affected by weather (especially light intensity), it has the characteristics of weak all-day power supply stability and difficult power supply estimation. Therefore, in order to avoid affecting the stability of power grid operation, some electrical equipment is needed for regulation.

[0004] However, this method of using electrical equipment for regulation is more suitable for large-scale photovoltaic power stations. However, due to the large investment, long construction period, and large floor area of large-scale photovoltaic power stations, the speed and quantity of their construction and grid connection are far less than those of decentralized small-scale photovoltaic power stations, especially photovoltaic power stations integrated with buildings. Small-scale power stations are characterized by small size, large quantity, high degree of dispersion, and small power supply of a single photovoltaic power station. If these electrical equipment are installed for regulation for all small-scale photovoltaic power stations, the cost will be greatly increased and the management will be very inconvenient. At the same time, in recent years, more and more newly grid-connected photovoltaic power stations have emerged. If a large number of grid connections are made in a short period, it will also affect the stability of power grid operation. Summary of the Invention

[0005] The purpose of the present invention is to provide a power grid planning method for grid connection of a photovoltaic power station, so as to solve the technical problem in the prior art that the all-day power supply stability of a photovoltaic power station is weak and the power supply is difficult to estimate, which easily affects the stability of power grid operation.

[0006] To achieve the above object, the technical solution adopted by the present invention is: to provide a power grid planning method for grid connection of a photovoltaic power station, including the following steps:

[0007] S300. Actual measurement: After connecting the target photovoltaic power station to the power grid, monitor the light intensity in the area where the target photovoltaic power station is located and the actual power supply of the target photovoltaic power station within a predetermined time period, and generate a second relationship curve of the light intensity and the actual power supply for the target photovoltaic power station;

[0008] S400. Re-plan, combine the weather forecast data of this area with the second relationship curve, estimate the future all-day power supply distribution of the target photovoltaic power station, and plan the power supply of the target photovoltaic power station according to the future all-day power supply distribution and the all-day power supply demand of the power grid in this area. Among them, the weather forecast data of this area includes the all-day light intensity distribution.

[0009] In a possible implementation manner, before step S300, it further includes:

[0010] S100. Historical estimation, combine the historical data of the operation of the photovoltaic power stations in this area with the historical light intensity data of this area to generate a first relationship curve between the light intensity and the power supply per unit area;

[0011] S200. Preliminary planning, combine the scale data of the target photovoltaic power station to be planned, the weather forecast data of this area and the first relationship curve, estimate the future all-day power supply distribution of the target photovoltaic power station, and conduct preliminary planning on the power supply of the target photovoltaic power station according to the future all-day power supply distribution and the all-day power supply demand of the power grid in this area. Among them, the scale data of the target photovoltaic power station includes the installed capacity of the target photovoltaic power station, and the weather forecast data of this area includes the all-day light intensity distribution.

[0012] In a possible implementation manner, step S100 includes:

[0013] S110. Obtain the historical data of the operation of the photovoltaic power stations in this area and the historical light intensity data. Among them, the historical data of the operation of the photovoltaic power stations includes the average power supply per unit area and the average power conversion rate within different time periods of the whole day, and the historical light intensity data includes the average light intensity within different time periods of the whole day. Among them, the average power supply per unit area within different time periods of the whole day refers to the average value of the power supply per unit time within each time period after dividing the whole day into multiple time periods, and the average light intensity within different time periods of the whole day refers to the average value of the light intensity per unit time within each time period after dividing the whole day into multiple time periods;

[0014] S120. Respectively establish a plane rectangular coordinate system with the power supply and the light intensity as the X-axis and the Y-axis, input the average power supply and the average light intensity corresponding to the same time period as a point into the plane rectangular coordinate system to form a scatter plot;

[0015] S130. Fit the first relationship curve on the scatter plot according to the density.

[0016] In a possible implementation, the regions in this area are divided according to the power grid management regions or according to the climate conditions. If there is historical data on the operation of photovoltaic power plants in this area, the historical data on the operation of photovoltaic power plants in this area is adopted. If there is no historical data on the operation of photovoltaic power plants in this area, the historical data on the operation of photovoltaic power plants in the areas adjacent to this area is adopted.

[0017] In a possible implementation, step S200 includes:

[0018] S210. Obtain the scale data of the target photovoltaic power plant to be planned, including the installed capacity and the theoretical power conversion rate of the target photovoltaic power plant to be planned;

[0019] S220. Use the ratio of the theoretical power conversion rate of the target photovoltaic power plant to be planned to the average power conversion rate in the historical data of the operation of photovoltaic power plants in this area to correct the first relationship curve, and form a corrected first relationship curve;

[0020] S230. Obtain the future all-day light intensity distribution through weather forecast data, and after importing the future all-day light intensity distribution into the corrected first relationship curve, generate the future all-day power supply distribution of the target photovoltaic power plant. The future all-day power supply distribution is the distribution of the maximum power supply that the target photovoltaic power plant can provide at different times in the future all day;

[0021] S240. Estimate the future all-day power supply demand of the power grid in this area. According to the future all-day power supply demand of the power grid in this area, make a preliminary plan for the grid-connected power of the target photovoltaic power plant in the future all day. When the power supply demand of the power grid at a certain future time is greater than or equal to the power supply of the target photovoltaic power plant at this time, the target photovoltaic power plant supplies power at full load. When the power supply demand of the power grid at a certain future time is less than the power supply of the target photovoltaic power plant at this time, the target photovoltaic power plant supplies power according to the power consumption gap;

[0022] S250. When the power grid in this area is operating, continuously judge the power supply demand of the power grid in this area. If the deviation between the power supply demand of the power grid in this area and the estimated power supply demand at this time is within the allowable range, grid-connected power supply is carried out according to the original preliminary plan; if the deviation between the power supply demand of the power grid in this area and the estimated power supply demand at this time exceeds the allowable range, correct the original preliminary plan, that is, increase or decrease the grid-connected power of the target photovoltaic power plant; among them, the allowable range of deviation is determined according to the allowable load of the power grid.

[0023] In a possible implementation, in step S220, the steps for correction include: multiplying the average power supply of the first relationship curve by the ratio.

[0024] In a possible implementation, step S300 includes:

[0025] After the target photovoltaic power station is connected to the grid, the average actual power supply per unit area within different time periods of the whole day for multiple days and the average actual light intensity within different time periods of the whole day in the area where the target photovoltaic power station is located are obtained through monitoring. Among them, the average actual power supply per unit area within different time periods of the whole day refers to the average value of the actual power supply per unit time within each time period after dividing the whole day into multiple time periods, and the average actual light intensity within different time periods of the whole day refers to the average value of the actual light intensity per unit time within each time period after dividing the whole day into multiple time periods;

[0026] S320: Establish a plane rectangular coordinate system with the actual power supply as the X-axis and the actual light intensity as the Y-axis, use the average actual power supply and the average actual light intensity corresponding to the same time period as the coordinates of a point, generate the coordinates of all the data for multiple days in step S310, and input them into the plane rectangular coordinate system to form a scatter plot;

[0027] S330: Fit the second relationship curve on the scatter plot according to the density.

[0028] In a possible implementation manner, step S400 includes:

[0029] S410: Obtain the future all-day light intensity distribution through weather forecast data, and after importing the future all-day light intensity distribution into the second relationship curve, generate the future all-day power supply distribution of the target photovoltaic power station. The future all-day power supply distribution is the maximum power supply distribution that the target photovoltaic power station can provide in different time periods of the future all day;

[0030] S420: Estimate the future all-day power supply demand of the local power grid. According to the future all-day power supply demand of the local power grid, make a preliminary plan for the grid-connected power of the target photovoltaic power station in the future all day. When the power supply demand of the power grid in a certain future time period is greater than or equal to the power supply of the target photovoltaic power station in that time period, the target photovoltaic power station supplies power at full load. When the power supply demand of the power grid in a certain future time period is less than the power supply of the target photovoltaic power station in that time period, the target photovoltaic power station supplies power according to the power consumption gap;

[0031] S430: When the local power grid is operating, continuously judge the power supply demand of the local power grid. If the deviation between the power supply demand of the local power grid and the estimated power supply demand in this time period is within the allowable range, grid-connected power supply is carried out according to the original preliminary plan; if the deviation between the power supply demand of the local power grid and the estimated power supply demand in this time period exceeds the allowable range, the original preliminary plan is corrected, that is, the grid-connected power of the target photovoltaic power station is increased or decreased; among them, the allowable range of deviation is determined according to the allowable load of the power grid.

[0032] In a possible implementation manner, the grid planning method for photovoltaic power station grid connection further includes the following steps:

[0033] S500, Intermittent correction: After the target photovoltaic power station has been operating for a period of time, repeat steps S300 and S400 for correction.

[0034] The intermittent correction is performed at least once per season.

[0035] In a possible implementation manner, the grid planning method for grid connection of a photovoltaic power station further includes the following steps:

[0036] S600, Fault feedback: During the operation of the target photovoltaic power station, if the deviation between the grid-connected power of the target photovoltaic power station and the estimated value exceeds the preset range in a short period of time, notify the operation and maintenance personnel of the target photovoltaic power station to inspect the target photovoltaic power station.

[0037] The beneficial effects of the grid planning method for grid connection of a photovoltaic power station provided by the present invention are as follows: Compared with the prior art, the present invention can first perform short-term actual measurements on the target photovoltaic power station, ignoring the unreliability of the parameters of the target photovoltaic power station itself, directly calculating the relationship curve between the light intensity and its actual power supply from the results after grid connection, and relying on this relationship curve to first deduce the light intensity distribution throughout the day in the future according to the weather forecast data, and then estimating the power supply distribution throughout the day in the future of the target photovoltaic power station according to the light intensity distribution throughout the day in the future. With the power supply distribution throughout the day in the future, it is possible to plan and adjust in advance the power supply supplemented by the photovoltaic power station to the grid according to the needs of the grid, which is equivalent to predicting the future power supply situation. Compared with installing electrical equipment, there is more time for response, regulation, correction, and remedy, thus avoiding installing complex electrical equipment for adjustment on each photovoltaic power station, which is beneficial to reducing the equipment costs of photovoltaic power generation and grid operation and maintenance, and is also more convenient for the management of operation and maintenance personnel. At the same time, it is beneficial to improve the safety and stability of grid operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0039] Figure 1 It is a schematic diagram of the grid planning method for grid connection of a photovoltaic power station provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] It should be noted that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more, and "several" means one or more, unless otherwise specifically defined.

[0042] Now, the grid planning method for grid connection of a photovoltaic power station provided by the present invention will be described.

[0043] The grid planning method for grid connection of a photovoltaic power station provided by the first embodiment of the present invention includes the following steps:

[0044] S100. Historical estimation: Combine the historical data of the operation of the photovoltaic power stations in the area with the historical light intensity data of the area to generate a first relationship curve between the light intensity and the power supply per unit area.

[0045] S200. Preliminary planning: Combine the scale data of the target photovoltaic power station to be planned, the weather forecast data of the area and the first relationship curve to estimate the future all-day power supply distribution of the target photovoltaic power station, and make a preliminary plan for the power supply of the target photovoltaic power station according to the future all-day power supply distribution and the all-day power supply demand of the power grid in the area. Among them, the scale data of the target photovoltaic power station includes the installed capacity of the target photovoltaic power station, and the weather forecast data of the area includes the all-day light intensity distribution.

[0046] S300. Actual measurement: After connecting the target photovoltaic power station to the power grid, monitor the light intensity and the actual power supply of the target photovoltaic power station in the area within a predetermined time period to generate a second relationship curve between the light intensity and the actual power supply for the target photovoltaic power station.

[0047] In the actual measurement stage, if conditions permit, try to make the target photovoltaic power station supply power at full load as much as possible so as to monitor more real data; if conditions do not permit and it is necessary to regulate it so that it cannot supply power at full load, then when processing the data, the regulated time period can be ignored or corrected. If the amount of data is insufficient due to this, the monitoring time can be increased.

[0048] S400. Re-plan, combine the weather forecast data of the area with the second relationship curve to estimate the future all-day power supply distribution of the target photovoltaic power station, and plan the power supply of the target photovoltaic power station according to the future all-day power supply distribution and the all-day power supply demand of the local power grid, where the weather forecast data of the area includes the all-day light intensity distribution.

[0049] S500. Intermittent correction: After the target photovoltaic power station has been operating for a period of time, repeat steps S300 and S400 for correction; the intermittent correction is performed at least once in each season.

[0050] S600. Fault feedback: During the operation of the target photovoltaic power station, if the deviation between the grid-connected power of the target photovoltaic power station and the estimated value exceeds the preset range in the short term, notify the operation and maintenance personnel of the target photovoltaic power station to inspect the target photovoltaic power station.

[0051] Since the light in the same area is approximately the same, in actual operation, the target photovoltaic power station can be a single photovoltaic power station or a collection of multiple identical photovoltaic power stations.

[0052] The grid planning method for grid connection of a photovoltaic power station provided in this embodiment first estimates through historical data to generate a first relationship curve between the light intensity and the power supply per unit area that is common to the photovoltaic power station. Then, based on the first relationship curve generated using historical data and combined with weather forecast data, it roughly estimates the future all-day power supply distribution of the photovoltaic power station, conducts prior planning for the target photovoltaic power station newly connected to the grid, and guides its operation. Although due to factors such as changes in the photoelectric conversion rate caused by technological upgrades, the historical data does not fully conform to the target photovoltaic power station newly connected to the grid, it can still make a rough estimate in terms of trend and carry out peak shaving and valley filling in a targeted manner, which can ensure the safety and stability of the grid to the greatest extent and greatly reduce the pressure on the safe operation of the grid brought by the grid connection of large-scale photovoltaic power stations and a large number of small-scale photovoltaic power stations. Then, through short-term actual measurement of the target photovoltaic power station after grid connection, the unreliability of the parameters of the target photovoltaic power station itself can be ignored, and a second relationship curve between the light intensity and its actual power supply can be directly measured from the results after grid connection. Relying on this relationship curve, first, the future all-day light intensity distribution is deduced according to the weather forecast data, and then the future all-day power supply distribution of the target photovoltaic power station is estimated based on the future all-day light intensity distribution. With the future all-day power supply distribution, it is possible to carry out prior planning and adjustment of the power supply supplemented by the photovoltaic power station to the grid according to the needs of the grid, which is equivalent to predicting the future power supply situation. Compared with installing electrical equipment, it has more time for response, regulation, correction, and remedy, thus avoiding installing complex electrical equipment for adjustment on each photovoltaic power station, which is beneficial to reducing the equipment costs of photovoltaic power generation and grid operation and maintenance, and is also more convenient for the management of maintenance personnel. At the same time, it is beneficial to improve the safety and stability of grid operation. After that, through intermittent correction, it is used to make up for the impact brought by the decrease in power supply caused by factors such as dust accumulation and equipment aging of the photovoltaic panels, and ensure the accuracy of regulation. If a fault occurs during the operation of the target photovoltaic power station, its daily operation data will change in the short term, and the maintenance personnel of the target photovoltaic power station can be notified through the method of fault feedback to check the target photovoltaic power station, which can not only avoid the expansion of losses of the target photovoltaic power station but also timely adjust the planning strategy according to the feedback situation to ensure the safe and stable operation of the grid.

[0053] The grid planning method for grid connection of a photovoltaic power station provided in the second embodiment of the present invention includes the following steps:

[0054] S110. Obtain the historical data of the operation of the photovoltaic power stations in this area and the historical light intensity data. Among them, the historical data of the operation of the photovoltaic power stations includes the average power supply per unit area and the average power conversion rate at different time periods throughout the day. The historical light intensity data includes the average light intensity at different time periods throughout the day. Among them, the average power supply per unit area at different time periods throughout the day refers to the average value of the power supply per unit time in each time period after dividing the whole day into multiple time periods. The average light intensity at different time periods throughout the day refers to the average value of the light intensity per unit time in each time period after dividing the whole day into multiple time periods.

[0055] Among them, the area of this area is divided according to the power grid management area or according to the climate conditions. If there is historical data of the operation of the photovoltaic power stations in this area, then the historical data of the operation of the photovoltaic power stations in this area is adopted. If there is no historical data of the operation of the photovoltaic power stations in this area, then the historical data of the operation of the photovoltaic power stations in the area adjacent to this area is adopted.

[0056] S120. Establish a plane rectangular coordinate system with the power supply and the light intensity as the X-axis and the Y-axis respectively. Input the average power supply and the average light intensity corresponding to the same time period as a point into the plane rectangular coordinate system to form a scatter plot.

[0057] S130. Fit the first relationship curve on the scatter plot according to the density. In this way, some measurement errors caused by special reasons can be ignored, making the relationship curve more accurate.

[0058] S210. Obtain the scale data of the target photovoltaic power station to be planned, including the installed capacity and the theoretical power conversion rate of the target photovoltaic power station to be planned;

[0059] S220. Use the ratio of the theoretical power conversion rate of the target photovoltaic power station to be planned to the average power conversion rate in the historical data of the operation of the photovoltaic power stations in this area to correct the first relationship curve to form a corrected first relationship curve. The steps for correction include: multiplying the average power supply of the first relationship curve by the ratio.

[0060] S230. Obtain the light intensity distribution for the whole future day through weather forecast data, and after importing the light intensity distribution for the whole future day into the corrected first relationship curve, generate the power supply distribution for the whole future day of the target photovoltaic power station. The power supply distribution for the whole future day is the maximum power supply distribution that the target photovoltaic power station can provide at different time periods in the whole future day;

[0061] S240. Estimate the future all-day power supply demand of the power grid in this area. According to the future all-day power supply demand of the power grid in this area, make a preliminary plan for the grid-connected power generation of the target photovoltaic power station throughout the day. When the power supply demand of the power grid in a certain future period is greater than or equal to the power supply of the target photovoltaic power station in this period, the target photovoltaic power station supplies power at full load. When the power supply demand of the power grid in a certain future period is less than the power supply of the target photovoltaic power station in this period, the target photovoltaic power station supplies power according to the power consumption gap;

[0062] S250. When the power grid in this area is operating, judge the power supply demand of the power grid in this area in real time. If the deviation between the power supply demand of the power grid in this area and the estimated power supply demand in this period is within the allowable range, grid-connected power supply shall be carried out according to the original preliminary plan. If the deviation between the power supply demand of the power grid in this area and the estimated power supply demand in this period exceeds the allowable range, the original preliminary plan shall be corrected, that is, increase or decrease the grid-connected power generation of the target photovoltaic power station; among them, the allowable range of deviation is determined according to the allowable load of the power grid.

[0063] S310. After the target photovoltaic power station is connected to the power grid, obtain the average actual power supply per unit area in different time periods of the whole day for multiple days through monitoring and the average actual light intensity in different time periods of the whole day in the area where the target photovoltaic power station is located. Among them, the average actual power supply per unit area in different time periods of the whole day refers to the average value of the actual power supply per unit time in each time period after dividing the whole day into multiple time periods, and the average actual light intensity in different time periods of the whole day refers to the average value of the actual light intensity per unit time in each time period after dividing the whole day into multiple time periods;

[0064] S320. Establish a plane rectangular coordinate system with the actual power supply as the X-axis and the actual light intensity as the Y-axis respectively. Take the corresponding average actual power supply and average actual light intensity in the same period as the coordinates of a point. Generate the coordinates of all the data for multiple days in step S310 and input them into the plane rectangular coordinate system to form a scatter plot;

[0065] S330. Fit the second relationship curve on the scatter plot according to the density.

[0066] S410. Obtain the future all-day light intensity distribution through weather forecast data, and after importing the future all-day light intensity distribution into the second relationship curve, generate the future all-day power supply distribution of the target photovoltaic power station. The future all-day power supply distribution is the maximum power supply distribution that the target photovoltaic power station can provide in different time periods of the future whole day;

[0067] S420. Estimate the future all-day power supply demand of the power grid in this area. According to the future all-day power supply demand of the power grid in this area, make a preliminary plan for the grid-connected power generation of the target photovoltaic power station throughout the day. When the power supply demand of the power grid in a certain future time period is greater than or equal to the power supply of the target photovoltaic power station in this time period, the target photovoltaic power station supplies power at full load. When the power supply demand of the power grid in a certain future time period is less than the power supply of the target photovoltaic power station in this time period, the target photovoltaic power station supplies power according to the power consumption gap part.

[0068] S430. When the power grid in this area is operating, judge the power supply demand of the power grid in this area in real time. If the deviation between the power supply demand of the power grid in this area and the estimated power supply demand in this time period is within the allowable range, grid-connected power supply shall be carried out according to the original preliminary plan. If the deviation between the power supply demand of the power grid in this area and the estimated power supply demand in this time period exceeds the allowable range, the original preliminary plan shall be corrected, that is, increase or decrease the grid-connected power generation of the target photovoltaic power station. Among them, the allowable range of deviation is determined according to the allowable load of the power grid.

[0069] S500. Intermittent correction: After the target photovoltaic power station has been operating for a period of time, repeat steps S300 and S400 for correction. Intermittent correction shall be carried out at least once in each season.

[0070] S600. Fault feedback: During the operation of the target photovoltaic power station, if the deviation between the grid-connected power generation of the target photovoltaic power station and the estimated value exceeds the preset range in a short period of time, notify the operation and maintenance personnel of the target photovoltaic power station to check the target photovoltaic power station.

[0071] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A grid planning method for grid connection of a photovoltaic power station, characterized in that, It includes the following steps: S100. Historical estimation: Combine the historical data of the operation of photovoltaic power stations in the area where the target photovoltaic power station is located with the historical light intensity data of this area to generate a first relationship curve between light intensity and power supply per unit area; S200. Preliminary planning: Combine the scale data of the target photovoltaic power station to be planned, the weather forecast data of this area and the first relationship curve to estimate the future all-day power supply distribution of the target photovoltaic power station, and based on the future all-day power supply distribution and the all-day power supply demand of the power grid in this area, conduct preliminary planning for the power supply of the target photovoltaic power station. Among them, the scale data of the target photovoltaic power station includes the installed capacity of the target photovoltaic power station, and the weather forecast data of this area includes the all-day light intensity distribution; S300. Actual measurement: After the target photovoltaic power station is connected to the power grid, monitor the light intensity in the area where the target photovoltaic power station is located and the actual power supply of the target photovoltaic power station within a predetermined time period to generate a second relationship curve between light intensity and actual power supply for the target photovoltaic power station; S400. Re-planning: Combine the weather forecast data of this area and the second relationship curve to estimate the future all-day power supply distribution of the target photovoltaic power station, and based on the future all-day power supply distribution and the all-day power supply demand of the power grid in this area, conduct planning for the power supply of the target photovoltaic power station. Among them, the weather forecast data of this area includes the all-day light intensity distribution.

2. The grid planning method for grid connection of a photovoltaic power station according to claim 1, characterized in that, Step S100 includes: S110. Obtain the historical data of the operation of photovoltaic power stations in this area and the historical light intensity data. Among them, the historical data of the operation of photovoltaic power stations includes the average power supply per unit area and the average power conversion rate within different time periods of the whole day, and the historical light intensity data includes the average light intensity within different time periods of the whole day. Among them, the average power supply per unit area within different time periods of the whole day refers to the average value of the power supply per unit time within each time period after dividing the whole day into multiple time periods, and the average light intensity within different time periods of the whole day refers to the average value of the light intensity per unit time within each time period after dividing the whole day into multiple time periods; S120. Establish a plane rectangular coordinate system with power supply and light intensity as the X-axis and Y-axis respectively, and input the average power supply and average light intensity corresponding to the same time period as a point into the plane rectangular coordinate system to form a scatter plot; S130. Fit the first relationship curve on the scatter plot according to the density.

3. The grid planning method for grid connection of a photovoltaic power station according to claim 2, characterized in that: The area is divided according to the power grid management area or according to the climate conditions. If there is historical data of the operation of photovoltaic power stations in this area, then use the historical data of the operation of photovoltaic power stations in this area. If there is no historical data of the operation of photovoltaic power stations in this area, then use the historical data of the operation of photovoltaic power stations in the area adjacent to this area.

4. The grid planning method for grid connection of a photovoltaic power station according to claim 2, wherein, Step S200 includes: S210. Obtain the scale data of the target photovoltaic power station to be planned, including the installed capacity and the theoretical power conversion rate of the target photovoltaic power station to be planned; S220. Modify the first relationship curve by using the ratio of the theoretical power conversion efficiency of the target photovoltaic power station to be planned and the average power conversion efficiency in the historical data of the operation of photovoltaic power stations in this area, so as to form a modified first relationship curve; S230. Obtain the future all-day light intensity distribution through weather forecast data, and after importing the future all-day light intensity distribution into the modified first relationship curve, generate the future all-day power supply distribution of the target photovoltaic power station. The future all-day power supply distribution is the distribution of the maximum power supply that the target photovoltaic power station can provide at different times of the future all day; S240. Estimate the future all-day power supply demand of the power grid in this area. According to the future all-day power supply demand of the power grid in this area, make a preliminary plan for the grid-connected power of the target photovoltaic power station in the future all day. When the power supply demand of the power grid in a certain future time period is greater than or equal to the power supply of the target photovoltaic power station in this time period, the target photovoltaic power station supplies power at full load. When the power supply demand of the power grid in a certain future time period is less than the power supply of the target photovoltaic power station in this time period, the target photovoltaic power station supplies power according to the power consumption gap; S250. When the power grid in this area is operating, judge the power supply demand of the power grid in this area in real time. If the deviation between the power supply demand of the power grid in this area and the estimated power supply demand in this time period is within the allowable range, grid-connected power supply shall be carried out according to the original preliminary plan; if the deviation between the power supply demand of the power grid in this area and the estimated power supply demand in this time period exceeds the allowable range, the original preliminary plan shall be modified, that is, increase or decrease the grid-connected power of the target photovoltaic power station; among them, the allowable range of deviation is determined according to the allowable load of the power grid.

5. The grid planning method for grid connection of a photovoltaic power station according to claim 4, characterized in that, In step S220, the modification steps include: multiplying the average power supply of the first relationship curve by the ratio.

6. The grid planning method for grid connection of a photovoltaic power station according to claim 1, wherein Step S300 includes: S310. After the target photovoltaic power station is connected to the power grid, obtain the average actual power supply per unit area at different times of the day for multiple days through monitoring and the average actual light intensity at different times of the day in the area where the target photovoltaic power station is located. Among them, the average actual power supply per unit area at different times of the day refers to the average value of the actual power supply per unit time in each time period after dividing the whole day into multiple time periods, and the average actual light intensity at different times of the day refers to the average value of the actual light intensity per unit time in each time period after dividing the whole day into multiple time periods; S320. Establish a plane rectangular coordinate system with the actual power supply as the X-axis and the actual light intensity as the Y-axis respectively. Use the average actual power supply and the average actual light intensity corresponding to the same time period as the coordinates of a point. Generate the coordinates of all the data of multiple days in step S310 and input them into the plane rectangular coordinate system to form a scatter plot; S330. Fit the second relationship curve on the scatter plot according to the density.

7. The grid planning method for grid connection of a photovoltaic power station according to claim 6, characterized in that, Step S400 includes: S410. Obtain the future all-day light intensity distribution through weather forecast data, and after importing the future all-day light intensity distribution into the second relationship curve, generate the future all-day power supply distribution of the target photovoltaic power station. The future all-day power supply distribution is the distribution of the maximum power supply that the target photovoltaic power station can provide at different times of the future all day; S420. Estimate the future all-day power supply demand of the local power grid. Based on the future all-day power supply demand of the local power grid, preliminarily plan the grid-connected power generation of the target photovoltaic power station for the whole day. When the power supply demand of the local power grid in a certain future period is greater than or equal to the power supply of the target photovoltaic power station in that period, the target photovoltaic power station supplies power at full load. When the power supply demand of the local power grid in a certain future period is less than the power supply of the target photovoltaic power station in that period, the target photovoltaic power station supplies power according to the power consumption gap. S430. When the local power grid is operating, continuously judge the power supply demand of the local power grid. If the deviation between the power supply demand of the local power grid and the estimated power supply demand in that period is within the allowable range, grid-connected power supply is carried out according to the original preliminary plan. If the deviation between the power supply demand of the local power grid and the estimated power supply demand in that period exceeds the allowable range, the original preliminary plan is corrected, that is, the grid-connected power generation of the target photovoltaic power station is increased or decreased. Among them, the allowable range of deviation is determined according to the allowable load of the power grid.

8. The grid planning method for grid connection of a photovoltaic power station according to claim 1, characterized in that, The grid planning method for grid connection of a photovoltaic power station further includes the following steps: S500. Intermittent correction: After the target photovoltaic power station has been operating for a period of time, repeat steps S300 and S400 for correction. The intermittent correction is carried out at least once in each season.

9. The grid planning method for photovoltaic power station grid connection according to claim 1, characterized in that, The grid planning method for grid connection of a photovoltaic power station further includes the following steps: S600. Fault feedback: During the operation of the target photovoltaic power station, if the deviation between the grid-connected power generation of the target photovoltaic power station and the estimated value exceeds the preset range in a short period, notify the operation and maintenance personnel of the target photovoltaic power station to check the target photovoltaic power station.

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