Intelligent management and control method and system based on photovoltaic grid-connected switch

Abstract

The invention discloses an intelligent management and control method and system based on a photovoltaic grid-connected switch, and relates to the technical field of power supply grid-connected management and control. The method comprises the following steps: acquiring a power grid load, and judging whether photovoltaic grid connection is needed; if photovoltaic grid connection needs to be carried out, the illumination intensity change condition is obtained, and the photovoltaic grid connection switching time is determined; obtaining the power grid access capability, and determining the number of photovoltaic grid-connected switches; obtaining a power grid structure of a photovoltaic grid-connected switch, and determining the position of the photovoltaic grid-connected switch; according to the positions of the photovoltaic grid-connected switches, counting the influence degree after each photovoltaic grid-connected switch is turned on, and determining the sequence of the photovoltaic grid-connected switches; and forming an intelligent control scheme of the photovoltaic grid-connected switches according to the photovoltaic grid-connected switch time, the photovoltaic grid-connected switch number, the photovoltaic grid-connected switch positions and the photovoltaic grid-connected switch sequence, and realizing remote operation according to the intelligent control scheme. According to the invention, the accuracy of intelligent control based on the photovoltaic grid-connected switch is improved.

Description

Technical Field

[0001] The present application relates to the technical field of power supply grid-connected control, and in particular to an intelligent control method and system based on photovoltaic grid-connected switches. Background Art

[0002] Photovoltaic grid connection refers to the energy integration process of putting the electric energy of renewable energy systems with energy conversion functions into the power supply network through the corresponding AC or DC system. This technology combines renewable energy with the existing power network to achieve the widespread use of renewable energy, which not only meets the user's requirements for energy-saving, convenient and efficient investment in renewable energy, but also meets the social needs of energy conservation and environmental protection. The photovoltaic grid-connected system has the advantages of high safety, low cost, and environmental friendliness. It can provide more stable energy security for the society, reduce greenhouse gas emissions, improve air quality, and effectively improve current environmental problems. In general photovoltaic grid connection, photovoltaic grid connection is achieved by controlling only one photovoltaic grid-connected switch. However, the number of photovoltaic grid-connected switches is not fixed. In some large photovoltaic power stations, multiple grid-connected switches are set up in order to achieve more effective power management and system protection. However, one-button control is not applicable to multiple grid-connected switches. One-button control of multiple grid-connected switches is not conducive to the operation of the power grid, making the remote operation of the grid-connected switch inaccurate. Summary of the invention

[0003] The object of the present invention is to provide an intelligent control method and system based on photovoltaic grid-connected switches to solve the problems raised in the above background technology.

[0004] In the first aspect, the present application provides an intelligent control method based on a photovoltaic grid-connected switch, which adopts the following technical solution:

[0005] Obtain the grid load and determine whether photovoltaic grid connection is required based on the grid load;

[0006] If photovoltaic grid connection is required, obtain the change of light intensity and determine the photovoltaic grid connection switch time according to the change of light intensity;

[0007] Obtain the grid access capacity, and determine the number of photovoltaic grid-connected switches based on the photovoltaic grid-connected switch time and the grid access capacity;

[0008] Obtain the grid structure of the photovoltaic grid-connected switch, and determine the location of the photovoltaic grid-connected switch according to the grid structure and the number of photovoltaic grid-connected switches;

[0009] According to the location of the photovoltaic grid-connected switches, the impact degree of each photovoltaic grid-connected switch after it is turned on is counted, and the photovoltaic grid-connected switch sequence is determined according to the impact degree;

[0010] An intelligent control plan for photovoltaic grid-connected switches is formed according to the photovoltaic grid-connected switch time, the number of photovoltaic grid-connected switches, the location of photovoltaic grid-connected switches and the sequence of photovoltaic grid-connected switches, and remote operation is achieved according to the intelligent control plan.

[0011] Preferably, if photovoltaic grid connection is required, the step of obtaining the change of light intensity and determining the photovoltaic grid connection switching time according to the change of light intensity is specifically as follows:

[0012] Obtain the changes in light intensity in the photovoltaic power generation area, predict the photovoltaic power generation at different time points based on the changes in light intensity, and form a photovoltaic power generation curve;

[0013] Obtain historical electricity consumption records, extract electricity load changes based on the historical electricity consumption records, and form an electricity load curve;

[0014] Set the standard load corresponding to the photovoltaic power generation, and form a corresponding standard load curve according to the photovoltaic power generation curve and the corresponding standard load;

[0015] Combine the power load curve and the standard load curve to calculate the load difference, set the load difference threshold, and select the time point when the load difference is not greater than the load difference threshold as the standard time point;

[0016] Standard time points without time intervals are combined to obtain multiple time collections, and the duration of the time collections is counted. The time collections whose duration exceeds a preset duration threshold are used as photovoltaic grid-connected switching time.

[0017] Preferably, the step of obtaining the grid access capability and determining the number of photovoltaic grid-connected switches in combination with the photovoltaic grid-connected switch time and the grid access capability is specifically as follows:

[0018] The photovoltaic power generation curve corresponding to the photovoltaic grid-connected switching time is extracted and recorded as the grid-connected power generation, and the photovoltaic power generation capacity is extracted based on the grid-connected power generation;

[0019] The maximum access capacity of the power grid is obtained, and the first number of switches is determined in combination with the photovoltaic power generation capacity;

[0020] Obtaining the resonance interference intensity, and finding the corresponding second switch quantity according to a preset resonance interference intensity-switch quantity table;

[0021] The number of photovoltaic grid-connected switches is analyzed by combining the first number of switches and the second number of switches.

[0022] Preferably, the step of obtaining the maximum access capacity of the power grid and determining the first number of switches in combination with the photovoltaic power generation capacity is specifically as follows:

[0023] Determine whether the grid will be overloaded based on the maximum access capacity and photovoltaic power generation capacity;

[0024] If an overload situation occurs, the average power generation capacity corresponding to the grid-connected switch is calculated, and combined with the maximum access capacity, the threshold value of the number of photovoltaic grid-connected switches is obtained;

[0025] The average power load is calculated based on the power load curve, and the average power generation corresponding to the grid-connected switch is statistically calculated. The number of standard switches is obtained by combining the average power load and the average power generation;

[0026] If the number of standard switches is not greater than the threshold number of photovoltaic grid-connected switches, the number of standard switches is used as the first number of switches;

[0027] If the number of standard switches is greater than the threshold number of photovoltaic grid-connected switches, the threshold number of photovoltaic grid-connected switches is used as the first number of switches;

[0028] If no overload situation occurs, the standard switch quantity is used as the first switch quantity.

[0029] Preferably, the step of analyzing and obtaining the number of photovoltaic grid-connected switches by combining the first number of switches and the second number of switches is specifically as follows:

[0030] Determine whether the number of the first switches is not less than the number of the second switches. If the number of the first switches is not less than the number of the second switches, use the number of the first switches as the number of photovoltaic grid-connected switches;

[0031] If the first switch quantity is less than the second switch quantity, determining whether the first switch quantity is a photovoltaic grid-connected switch quantity threshold;

[0032] If it is the photovoltaic grid-connected switch quantity threshold, the first switch quantity is used as the photovoltaic grid-connected switch quantity;

[0033] If it is not the photovoltaic grid-connected switch quantity threshold, a quantity weight ratio between the first switch quantity and the second switch quantity is set, and the photovoltaic grid-connected switch quantity is calculated according to the first switch quantity, the second switch quantity and the corresponding quantity weight ratio.

[0034] Preferably, the step of obtaining the grid structure of the photovoltaic grid-connected switch and determining the position of the photovoltaic grid-connected switch according to the grid structure and the number of photovoltaic grid-connected switches is specifically as follows:

[0035] The location of the photovoltaic grid-connected switch is used as the grid-connected point location to form a grid-connected point location map;

[0036] Obtain the grid structure layout diagram, and obtain the grid area corresponding to the grid connection point according to the grid connection point location diagram and the grid structure layout diagram;

[0037] Obtain the regional access capacity of the power grid area, obtain the power generation capacity of the grid connection point and record it as the switch power generation capacity, filter out the grid connection points whose switch power generation capacity is greater than the corresponding regional access capacity, and obtain the primary grid connection point;

[0038] The power generation of the grid-connected point is obtained and recorded as the switch power generation, and the corresponding switch load is obtained according to the switch power generation;

[0039] Obtaining the regional load of the power grid area, calculating the difference between the switch load and the regional load and recording it as a first difference, setting a first difference threshold, screening and removing primary grid connection points whose first difference is greater than the difference threshold, and obtaining intermediate grid connection points;

[0040] Evaluate the grid connection success rate and grid connection safety rate of the intermediate grid connection points, set the grid connection weight ratios of the grid connection success rate and the grid connection safety rate respectively, and calculate the grid connection adaptation rate according to the grid connection success rate, the grid connection safety rate and the corresponding grid connection weight ratio;

[0041] According to the grid-connected adaptation rate, the intermediate grid-connected points are sorted from large to small. According to the number of photovoltaic grid-connected switches, the intermediate grid-connected points with the corresponding number in front of the sorting are selected and recorded as advanced grid-connected points. The switches of the advanced grid-connected points are used as the photovoltaic grid-connected switch positions.

[0042] Preferably, the step of evaluating the grid connection success rate and grid connection safety rate of the intermediate grid connection point is specifically:

[0043] Acquiring environmental data of the intermediate grid connection point, the environmental data including temperature, humidity and wind speed;

[0044] The surface temperature of the photovoltaic panel caused by the temperature is obtained, and the reduced temperature of the photovoltaic panel when the wind speed is reduced is obtained according to the wind speed. The surface temperature and the reduced temperature are superimposed to obtain the actual temperature of the photovoltaic panel;

[0045] Obtaining a temperature threshold that affects power generation performance, determining whether the actual temperature reaches the temperature threshold, and if so, calculating the temperature difference between the actual temperature and the temperature threshold;

[0046] Obtaining a humidity threshold that affects power generation efficiency, determining whether the humidity reaches the humidity threshold, and if so, calculating a humidity difference between the humidity and the humidity threshold;

[0047] The difference weight ratios of the temperature difference and the humidity difference are set respectively, and the grid connection success rate is calculated according to the temperature difference, the humidity difference and the corresponding difference weight ratios.

[0048] Preferably, the step of evaluating the grid connection success rate and grid connection safety rate of the intermediate grid connection point is specifically:

[0049] Obtain a grid access point corresponding to the intermediate grid connection point and record it as the intermediate access point, and obtain the structural solidity of the grid area corresponding to the intermediate access point;

[0050] Obtain the voltage fluctuation frequency and harmonic content of the generated electric energy at the intermediate grid connection point to evaluate the power quality;

[0051] The grid stability of the intermediate access point is obtained, and the grid connection safety rate is calculated based on the structural strength and power quality.

[0052] Preferably, the step of counting the influence degree of each photovoltaic grid-connected switch after it is turned on according to the position of the photovoltaic grid-connected switch and determining the photovoltaic grid-connected switch sequence according to the influence degree is specifically as follows:

[0053] Obtain the importance of advanced access points in the grid structure layout;

[0054] Evaluate the generation capacity of advanced grid connection points based on their generation capacity and generation output;

[0055] The impact of advanced access points on the power grid is obtained by combining importance and power generation capacity;

[0056] The order of photovoltaic grid-connected switches is obtained by sorting them according to the degree of impact.

[0057] In the second aspect, the present application provides an intelligent management and control system based on photovoltaic grid-connected switches, which adopts the following technical solutions:

[0058] An intelligent control system based on photovoltaic grid-connected switches, comprising:

[0059] The grid connection judgment module obtains the grid load and determines whether photovoltaic grid connection is required based on the grid load;

[0060] The switch time module obtains the change of light intensity if photovoltaic grid connection is required, and determines the photovoltaic grid connection switch time according to the change of light intensity;

[0061] The switch quantity module obtains the grid access capacity and determines the number of photovoltaic grid-connected switches based on the photovoltaic grid-connected switch time and the grid access capacity;

[0062] The switch position module obtains the grid structure of the photovoltaic grid-connected switch and determines the position of the photovoltaic grid-connected switch according to the grid structure and the number of photovoltaic grid-connected switches;

[0063] The switch sequence module counts the impact of each photovoltaic grid-connected switch after it is turned on according to the position of the photovoltaic grid-connected switch, and determines the photovoltaic grid-connected switch sequence according to the impact;

[0064] The intelligent management and control module forms an intelligent management and control plan for photovoltaic grid-connected switches according to the photovoltaic grid-connected switch time, the number of photovoltaic grid-connected switches, the location of photovoltaic grid-connected switches and the sequence of photovoltaic grid-connected switches, and realizes remote operation according to the intelligent management and control plan.

[0065] In summary, the present application includes at least one of the following beneficial technical effects:

[0066] 1. The photovoltaic grid-connected switch time is determined by the change of light intensity, the number of photovoltaic grid-connected switches is determined according to the grid access capacity, the photovoltaic grid-connected switch position is obtained by using the grid structure, and the photovoltaic grid switch sequence is obtained in combination with the degree of influence after the grid-connected switch is turned on, thereby forming an intelligent management and control scheme for photovoltaic grid-connected switches, which provides convenience for remote operation of the photovoltaic grid-connected switch. At the same time, the intelligent management and control scheme is more in line with the actual situation, which improves the accuracy of intelligent management and control based on photovoltaic grid-connected switches.

[0067] 2. Use the change of light intensity to confirm the photovoltaic power generation and photovoltaic power generation capacity, and combine the change of grid load caused by user electricity consumption to analyze the suitability of photovoltaic power generation and grid operation in different time periods, so as to determine the appropriate photovoltaic grid-connected switching time. Connecting to the grid within the appropriate photovoltaic grid-connected switching time reduces the waste of power generation and unstable power generation during the grid-connected process.

[0068] 3. According to the temperature, humidity and wind speed of the intermediate grid-connected point corresponding to the photovoltaic grid-connected switch, the grid connection success rate is analyzed. The grid connection safety rate is calculated by using the structural strength of the grid area corresponding to the intermediate access point, and the power quality obtained by evaluating the voltage fluctuation frequency and harmonic content of the generated electric energy at the intermediate grid-connected point, combined with the grid stability of the intermediate access point. The grid connection adaptation rate is then obtained based on the grid connection success rate and grid connection safety rate, so as to select the photovoltaic grid-connected switch in a suitable position as the switch to be opened for subsequent grid connection. The grid connection success rate and grid connection safety rate are effectively improved, and the intelligence of intelligent management and control based on photovoltaic grid-connected switches is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 It is a schematic diagram of specific steps of an embodiment of an intelligent control method based on a photovoltaic grid-connected switch of the present invention.

[0070] Figure 2 It is a module connection diagram of an embodiment of an intelligent management and control system based on a photovoltaic grid-connected switch of the present invention. DETAILED DESCRIPTION

[0071] Below is a combination of the embodiments and Figure 1-Figure 2 The present invention is further described in detail, but the embodiments of the present invention are not limited thereto.

[0072] The present invention discloses an intelligent control method based on a photovoltaic grid-connected switch, which specifically includes the following steps:

[0073] Step S1, obtaining the grid load, and determining whether photovoltaic grid connection is required according to the grid load.

[0074] When the power grid can support the user's electricity consumption and will not affect the user's electricity consumption, there is naturally no need for photovoltaic grid connection. When the power grid is difficult to support the user's electricity consumption, photovoltaic grid connection is needed to reduce the impact of power supply on users, so it is necessary to observe the grid load. For example, summer is the peak season for electricity consumption in the region, especially in the afternoon when the grid load reaches its peak. Through real-time monitoring equipment, it is found that the grid load during this period continues to rise, approaching or exceeding the upper limit of the grid capacity. The grid load during this period is predicted using historical data and prediction models. The results show that the grid load will continue to remain high in the afternoon in the next few days. It can be seen that in the afternoon of summer, the grid load has reached its peak, and photovoltaic grid connection is needed to maintain stable power supply to the grid.

[0075] Step S2: if photovoltaic grid connection is required, the change of light intensity is obtained, and the photovoltaic grid connection switching time is determined according to the change of light intensity.

[0076] Step S3, obtaining the grid access capability, and determining the number of photovoltaic grid-connected switches in combination with the photovoltaic grid-connected switch time and the grid access capability.

[0077] Step S4, obtaining the grid structure of the photovoltaic grid-connected switches, and determining the positions of the photovoltaic grid-connected switches according to the grid structure and the number of photovoltaic grid-connected switches.

[0078] Step S5, counting the impact of each photovoltaic grid-connected switch after it is turned on according to the position of the photovoltaic grid-connected switch, and determining the photovoltaic grid-connected switch sequence according to the impact degree.

[0079] Step S6, forming an intelligent control plan for the photovoltaic grid-connected switches according to the photovoltaic grid-connected switch time, the number of photovoltaic grid-connected switches, the positions of the photovoltaic grid-connected switches and the sequence of the photovoltaic grid-connected switches, and realizing remote operation according to the intelligent control plan.

[0080] When the photovoltaic grid-connected switch time period is reached, the photovoltaic grid-connected switches at the photovoltaic grid-connected switch positions corresponding to the number of photovoltaic grid-connected switches are opened one by one in the order of the photovoltaic grid-connected switches through remote operation to achieve photovoltaic grid connection.

[0081] In actual use, the number of photovoltaic grid-connected switches is not fixed. It depends on the specific scale, design and grid-connected mode of the photovoltaic power station. In some large photovoltaic power stations, multiple grid-connected switches are set up to achieve more effective power management and system protection. These switches are distributed at different grid-connected points or different circuits to control the connection between the photovoltaic power station and the power grid. Therefore, one-button control is only applicable to the case of one photovoltaic grid-connected switch. If multiple grid-connected switches are turned on at the same time, on the one hand, the power grid may not be able to bear it, and on the other hand, the impact of turning on the power grid at the same time is too large, which is easy to cause power grid failure. Therefore, when remotely controlling the opening of the photovoltaic grid-connected switch, it is necessary to consider the time, quantity, location and sequence of the opening of the photovoltaic grid-connected switch to achieve a smoother and safer photovoltaic grid connection.

[0082] If photovoltaic grid connection is required, the change of light intensity is obtained, and the steps for determining the photovoltaic grid connection switching time according to the change of light intensity are as follows:

[0083] Step S21, obtaining the change of light intensity in the photovoltaic power generation area, predicting the photovoltaic power generation at different time points according to the change of light intensity, and forming a photovoltaic power generation curve.

[0084] Step S22, obtaining historical electricity consumption records, extracting electricity load changes according to the historical electricity consumption records, and forming an electricity load curve.

[0085] Step S23, setting a standard load corresponding to the photovoltaic power generation, and forming a corresponding standard load curve according to the photovoltaic power generation curve and the corresponding standard load.

[0086] Step S24, combining the power load curve and the standard load curve, calculating the load difference, setting the load difference threshold, and selecting the time point when the load difference is not greater than the load difference threshold as the standard time point.

[0087] Step S25, forming a collection of standard time points without time intervals to obtain multiple time collections, counting the duration of the time collections, and taking the time collection whose duration exceeds a preset duration threshold as the photovoltaic grid-connected switching time.

[0088] In actual use, not all times are suitable for grid connection. On the one hand, the grid has a demand for electricity, and on the other hand, photovoltaic power generation has sufficient and stable electricity. Changes in light intensity directly affect the output power and stability of the photovoltaic power generation system. Grid connection during periods of high light intensity can ensure that the photovoltaic power generation system operates at a higher efficiency. When the grid load is high, it means that users consume more electricity. At this time, the electricity consumption of photovoltaic grid connection can also increase because users can consume it. Therefore, photovoltaic power generation has its corresponding standard load. When the power generation is larger, the standard load needs to be larger so that the grid can consume photovoltaic power generation and not cause waste of photovoltaic power generation. The greater the difference between the power load curve and the standard load curve, the lower the adaptability of the two, and the less suitable this time period is for grid connection. For example, if the grid load is low and the photovoltaic power generation is high at this time, then grid connection will obviously cause a waste of electricity. If the grid load is high and the photovoltaic power generation is low at this time, then grid connection will obviously be difficult to support user electricity consumption, and it will also cause fluctuations to the grid due to grid connection, and it is not suitable for grid connection. Frequent opening and closing of the grid connection switch will also cause grid fluctuations, so the time point suitable for grid connection should be continuous in a certain period of time. For example, 1pm to 5pm is suitable for grid connection, which is a relatively long grid connection time period that complies with regulations. However, 8am, 9am and 10am are not suitable for grid connection, as it is impossible to connect to the specified time period. Therefore, 8am to 10am is not suitable for grid connection.

[0089] The steps to obtain the grid access capability and determine the number of photovoltaic grid-connected switches in combination with the photovoltaic grid-connected switch time and the grid access capability are as follows:

[0090] Step S31, extracting the photovoltaic power generation curve corresponding to the photovoltaic grid-connected switching time and recording it as the grid-connected power generation, and extracting the photovoltaic power generation capacity based on the grid-connected power generation.

[0091] Step S32, obtaining the maximum access capacity of the power grid, and determining the first number of switches in combination with the photovoltaic power generation capacity.

[0092] Step S33, obtaining the resonance interference intensity, and searching for the corresponding second switch quantity according to a preset resonance interference intensity-switch quantity table.

[0093] The greater the intensity of the resonance interference, the more photovoltaic grid-connected switches are required, because increasing the number of photovoltaic grid-connected switches can reduce the resonance interference.

[0094] Step S34, combining the first switch quantity and the second switch quantity, analyzing and obtaining the photovoltaic grid-connected switch quantity.

[0095] In actual use, the maximum access capacity of the grid refers to the maximum photovoltaic power generation capacity that can be connected to the grid under the premise of safe operation. Photovoltaic power generation capacity refers to the maximum value of the electric energy that can be generated by the power generation equipment within a certain period of time. The more photovoltaic grid-connected switches there are, the more photovoltaic power generation equipment is connected, and the power generation capacity will increase. Therefore, the number of photovoltaic switches turned on needs to consider the maximum access capacity of the grid. Grid resonance refers to the improper coordination of certain parameters in the power system, which causes the system to produce strong resonance at certain frequencies. When the number of photovoltaic grid-connected switches increases, it means the increase in the number of grid-connected points, and the harmonic sources originally concentrated in a few grid-connected points are dispersed to more grid-connected points. The increase in the number of grid-connected switches will also change the overall impedance characteristics of the grid. The impedance of the grid is one of the important factors affecting resonance. By increasing the number of grid-connected switches, the impedance distribution of the grid can be adjusted, making it more difficult for the system to reach the resonance condition, thereby reducing the possibility of resonance. In addition, a mutually supportive relationship can be formed between multiple grid-connected points to enhance the overall stability of the grid. When a grid-connected point resonates, other grid-connected points can provide additional damping to suppress the spread and aggravation of the resonance. Therefore, when setting the number of photovoltaic grid-connected switches, resonance interference also needs to be considered.

[0096] The steps of obtaining the maximum access capacity of the power grid and determining the first number of switches in combination with the photovoltaic power generation capacity are specifically as follows:

[0097] Step S321, judging whether the power grid will be overloaded according to the maximum access capacity and the photovoltaic power generation capacity.

[0098] Step S322: If an overload situation occurs, the average power generation capacity corresponding to the grid-connected switch is calculated, and combined with the maximum access capacity, a threshold value of the number of photovoltaic grid-connected switches is obtained.

[0099] Step S323, calculate the average power load according to the power load curve, calculate the average power generation corresponding to the grid-connected switches, and obtain the standard switch quantity by combining the average power load and the average power generation.

[0100] Step S324: if the number of standard switches is not greater than the threshold number of photovoltaic grid-connected switches, the number of standard switches is used as the first number of switches.

[0101] Step S325: if the standard switch quantity is greater than the photovoltaic grid-connected switch quantity threshold, the photovoltaic grid-connected switch quantity threshold is used as the first switch quantity.

[0102] Step S326: If no overload occurs, the standard switch quantity is used as the first switch quantity.

[0103] In actual use, the access capacity of the power grid is limited. When the photovoltaic power generation capacity is greater than the maximum access capacity of the power grid, the power grid will be overloaded. Therefore, the number of photovoltaic switches should be controlled to achieve a photovoltaic power generation capacity less than the maximum access capacity of the power grid. The photovoltaic power generation should be equal to the user's power consumption, so that neither insufficient power consumption nor excessive power generation will be caused. Therefore, the required photovoltaic power generation switches are determined according to the load conditions. If the number of standard switches required is less than the switch number threshold, it means that there will be no overload, and the number of standard switches is used as the first switch number. When the number of standard switches exceeds the switch number threshold, using the standard switch as the first switch number will cause overload, so the switch number threshold can only be used as the first switch number. If there is no overload, it means that even if all photovoltaic switches are turned on, the photovoltaic power generation capacity is still not greater than the access capacity of the power grid. At this time, no matter how many standard switches there are, they can be directly used as the first switch number.

[0104] Combining the first switch quantity and the second switch quantity, the steps of analyzing and obtaining the number of photovoltaic grid-connected switches are specifically as follows:

[0105] Step S341, determining whether the number of first switches is not less than the number of second switches, if the number of first switches is not less than the number of second switches, taking the number of first switches as the number of photovoltaic grid-connected switches.

[0106] Step S342: if the first switch quantity is less than the second switch quantity, determine whether the first switch quantity is a photovoltaic grid-connected switch quantity threshold.

[0107] Step S343: If the photovoltaic grid-connected switch quantity threshold is reached, the first switch quantity is used as the photovoltaic grid-connected switch quantity.

[0108] Step S344: if it is not the photovoltaic grid-connected switch quantity threshold, then set the quantity weight ratio of the first switch quantity and the second switch quantity, and calculate the photovoltaic grid-connected switch quantity according to the first switch quantity, the second switch quantity and the corresponding quantity weight ratio.

[0109] In actual use, the number of grid switches needs to consider the maximum access capacity of the grid and the resonance. If the number of the first switch is not less than the number of the second switch, the first switch number is used as the number of photovoltaic grid-connected switches, which means that it can meet the need to reduce resonance and will not exceed the access capacity of the grid. If the number of the first switch is less than the number of the second switch, it is determined whether the maximum access capacity of the grid has been reached by judging whether the first switch number is the threshold of the number of photovoltaic grid-connected switches. If it is the threshold, it means that grid connection according to the second switch number will cause an overload phenomenon. At this time, only the first switch number can be used as the number of photovoltaic grid-connected switches. If it is not the threshold, the number of grid switches can also be increased. At this time, the weight ratio of the two switch numbers is set to calculate the number of photovoltaic grid-connected switches.

[0110] The steps of obtaining the grid structure of the photovoltaic grid-connected switch and determining the location of the photovoltaic grid-connected switch according to the grid structure and the number of photovoltaic grid-connected switches are as follows:

[0111] Step S41, taking the location of the photovoltaic grid-connected switch as the grid-connected point location, and forming a grid-connected point location map.

[0112] Step S42, obtaining a grid structure layout diagram, and obtaining a grid area corresponding to the grid connection point according to the grid connection point location diagram and the grid structure layout diagram.

[0113] Step S43, obtaining the regional access capacity of the power grid area, obtaining the power generation capacity of the grid connection point and recording it as the switch power generation capacity, screening and removing the grid connection points whose switch power generation capacity is greater than the corresponding regional access capacity, and obtaining the primary grid connection point.

[0114] Step S44, obtaining the power generation of the grid-connected point and recording it as the switch power generation, and obtaining the corresponding switch load according to the switch power generation.

[0115] Step S45, obtaining the regional load of the power grid area, calculating the difference between the switch load and the regional load and recording it as the first difference, setting the first difference threshold, screening and removing the primary grid connection points whose first difference is greater than the difference threshold, and obtaining the intermediate grid connection points.

[0116] Step S46, evaluate the grid connection success rate and grid connection safety rate of the intermediate grid connection point, set the grid connection weight ratio of the grid connection success rate and the grid connection safety rate respectively, and calculate the grid connection adaptation rate according to the grid connection success rate, the grid connection safety rate and the corresponding grid connection weight ratio.

[0117] Step S47, sort the intermediate grid-connected points from large to small according to the grid-connected adaptability rate, select the intermediate grid-connected points with a corresponding number in front of the sort according to the number of photovoltaic grid-connected switches and record them as advanced grid-connected points, and use the switches of the advanced grid-connected points as photovoltaic grid-connected switch positions.

[0118] In actual application, after the number of grid-connected switches is determined, because the number of grid-connected switches is not the number of all grid-connected switches, it is necessary to select switches from the grid-connected switches for grid connection. The grid access capacity of each region is different, and the photovoltaic power generation capacity of the grid-connected points represented by different grid-connected switches is also different. Therefore, the grid-connected points that will cause overload are first excluded. Then, the grid-connected points with too large load difference, that is, the grid-connected points where the power generation and power consumption do not match, are removed. Then, according to the grid connection success rate and grid connection safety rate of different grid-connected points, suitable grid-connected points are selected to obtain the grid-connected switches at the corresponding positions.

[0119] The steps to evaluate the grid connection success rate and grid connection safety rate of intermediate grid connection points are as follows:

[0120] Step S461, obtaining environmental data of the intermediate grid connection point, the environmental data including temperature, humidity and wind speed.

[0121] Step S462, obtaining the surface temperature of the photovoltaic panel caused by the temperature, obtaining the reduced temperature of the photovoltaic panel when the wind speed is reduced according to the wind speed, superimposing the surface temperature and the reduced temperature to obtain the actual temperature of the photovoltaic panel.

[0122] Step S463, obtaining a temperature threshold affecting power generation performance, determining whether the actual temperature reaches the temperature threshold, and if so, calculating a temperature difference between the actual temperature and the temperature threshold.

[0123] Step S464, obtaining a humidity threshold affecting power generation efficiency, determining whether the humidity has reached the humidity threshold, and if so, calculating a humidity difference between the humidity and the humidity threshold.

[0124] Step S465, respectively setting the difference weight ratios of the temperature difference and the humidity difference, and calculating the grid connection success rate according to the temperature difference, the humidity difference and the corresponding difference weight ratios.

[0125] In actual use, the increase in temperature will lead to a decrease in the efficiency of photovoltaic panels. When solar panels are exposed to high temperatures, the conductivity of semiconductor materials will be affected, and the recombination rate of electrons and holes will increase, thereby reducing the conversion efficiency of photovoltaic panels and increasing the difficulty of grid connection. The impact of wind speed on photovoltaic systems is mainly reflected in two aspects: heat dissipation and stability. Moderate wind speed can reduce the temperature of photovoltaic panels and improve the efficiency of the system. In areas with moderate wind, moderate wind speed can help photovoltaic systems dissipate heat and reduce the temperature of panels, thereby improving power generation efficiency and grid connection success rate. For example, in the afternoon of summer, when the temperature of photovoltaic panels is high, a breeze can quickly reduce its temperature and improve power generation efficiency. Humidity mainly affects the heat dissipation effect and atmospheric transparency of photovoltaic systems. Higher humidity can cause water accumulation or condensation on the surface of photovoltaic modules, reduce the transmittance of light, and thus reduce power generation efficiency. The power generation efficiency of photovoltaic power generation systems directly affects the stability and reliability of their power generation. If the power generation efficiency fluctuates greatly due to environmental factors such as temperature and humidity, the power quality output by the photovoltaic power generation system will be unstable, making it difficult to meet the grid's requirements for grid-connected power quality. In order to ensure its safe and stable operation, the power grid has strict standards and restrictions on the output power quality of grid-connected power sources. The unstable power generation efficiency of photovoltaic power generation systems may cause them to fail to meet these standards, thereby reducing the success rate of grid connection.

[0126] The steps to evaluate the grid connection success rate and grid connection safety rate of intermediate grid connection points are as follows:

[0127] Step S466, obtaining a grid access point corresponding to the intermediate grid connection point and recording it as the intermediate access point, and obtaining the structural strength of the grid area corresponding to the intermediate access point.

[0128] Step S467, obtaining the voltage fluctuation frequency and harmonic content of the generated electric energy at the intermediate grid-connected point to evaluate and obtain the power quality.

[0129] Set the optimal values ​​of the voltage fluctuation frequency and harmonic content of the generated electric energy, and calculate the differences between the voltage fluctuation frequency and harmonic content and the optimal values. The larger the difference, the lower the power quality, and the smaller the difference, the higher the power quality.

[0130] Step S468, obtaining the grid stability of the intermediate access point, combining the structural strength and the power quality, and calculating the grid connection safety rate.

[0131] In actual application, the weight ratios of grid stability, structural strength and power quality are set respectively, and the grid connection safety rate is calculated according to the grid stability, structural strength, power quality and the corresponding weight ratios. Voltage fluctuation means that the voltage value in the grid changes continuously within a certain range. This change will cause other equipment in the grid (such as transformers, capacitors, etc.) to be adversely affected, thereby affecting the stability and safety of the entire grid. The inverter in the photovoltaic power generation system will generate harmonics during operation. Harmonics are a non-sinusoidal waveform that will pollute the grid. The presence of harmonics will increase the reactive power loss in the grid, reduce the power supply efficiency of the grid, and make the grid prone to failure. A strong grid structure usually has a higher redundancy, that is, when some equipment or lines fail, other equipment or lines can quickly take over the work of the faulty part to ensure the continuous power supply of the grid. A stable grid can better protect the equipment in the grid from damage. When a grid fails, a stable grid can quickly isolate the faulty part and restore power supply, reducing the risk of equipment damage. Ensuring the safety of grid connection is conducive to reducing failures, thereby reducing the inconvenience caused to users by grid failures.

[0132] According to the positions of photovoltaic grid-connected switches, the impact degree of each photovoltaic grid-connected switch after opening is counted, and the steps for determining the photovoltaic grid-connected switch sequence according to the impact degree are as follows:

[0133] Step S51, obtaining the importance of the high-level access point in the grid structure layout.

[0134] The grid-connected access point corresponding to the advanced grid-connected point is recorded as the advanced access point.

[0135] Step S52, evaluating the power generation capability of the advanced grid connection point according to the power generation capacity and power generation of the advanced grid connection point.

[0136] The greater the power generation capacity of the grid-connected point, the greater its impact on the grid. This is because a large-capacity photovoltaic power generation system will inject more electricity into the grid after being connected to the grid, thus having a greater impact on the voltage, frequency and stability of the grid. The greater the power generation capacity and power generation, the stronger the power generation capacity.

[0137] Step S53: The influence of the advanced access point on the power grid is obtained by combining the importance and the power generation capacity.

[0138] Step S54, sorting according to the degree of influence to obtain the photovoltaic grid-connected switch sequence.

[0139] In actual use, the more important the advanced access point is in the power grid, the greater the impact of the fault and the greater the impact on the power grid. The stronger the power generation capacity of the advanced grid connection point, the greater the impact on the power grid when connected to the grid. Prioritize grid connection points with small impact for grid connection, so that the load of the power grid can be gradually increased, avoiding excessive impact on the power grid and improving the safety and stability of the grid connection process.

[0140] An intelligent control system based on a photovoltaic grid-connected switch, by applying the above-mentioned intelligent control method based on a photovoltaic grid-connected switch, comprises:

[0141] The grid connection judgment module obtains the grid load and determines whether photovoltaic grid connection is required based on the grid load.

[0142] The switching time module obtains the change of light intensity if photovoltaic grid connection is required, and determines the photovoltaic grid connection switching time according to the change of light intensity.

[0143] The switch quantity module obtains the grid access capacity and determines the number of photovoltaic grid-connected switches based on the photovoltaic grid-connected switch time and the grid access capacity.

[0144] The switch position module obtains the grid structure of the photovoltaic grid-connected switch and determines the position of the photovoltaic grid-connected switch according to the grid structure and the number of photovoltaic grid-connected switches.

[0145] The switch sequence module counts the impact of each photovoltaic grid-connected switch after it is turned on according to the position of the photovoltaic grid-connected switch, and determines the photovoltaic grid-connected switch sequence according to the impact degree.

[0146] The intelligent management and control module forms an intelligent management and control plan for photovoltaic grid-connected switches according to the photovoltaic grid-connected switch time, the number of photovoltaic grid-connected switches, the location of photovoltaic grid-connected switches and the sequence of photovoltaic grid-connected switches, and realizes remote operation according to the intelligent management and control plan.

[0147] In actual use, in some large-scale photovoltaic power stations, multiple grid-connected switches are set up to achieve more effective power management and system protection. Multiple grid-connected switches are controlled by remote operation. When and in what order to open the grid-connected switches at which positions are the key considerations for grid connection. Through the changes in light intensity, grid access capabilities, grid structure and degree of influence, the opening time, opening number, opening position and opening order of photovoltaic grid switches are obtained respectively, which provides convenience for remote operation of photovoltaic grid-connected switches and improves the stability and safety of photovoltaic grid connection.

[0148] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An intelligent control method based on photovoltaic grid-connected switches, characterized in that: The following steps are involved: Obtain the grid load and determine whether photovoltaic grid connection is required based on the grid load; If photovoltaic grid connection is required, obtain the change of light intensity and determine the photovoltaic grid connection switch time according to the change of light intensity; Obtain the grid access capacity, and determine the number of photovoltaic grid-connected switches based on the photovoltaic grid-connected switch time and the grid access capacity; Obtain the grid structure of the photovoltaic grid-connected switch, and determine the location of the photovoltaic grid-connected switch according to the grid structure and the number of photovoltaic grid-connected switches; According to the location of the photovoltaic grid-connected switches, the impact degree of each photovoltaic grid-connected switch after it is turned on is counted, and the photovoltaic grid-connected switch sequence is determined according to the impact degree; An intelligent control plan for photovoltaic grid-connected switches is formed according to the photovoltaic grid-connected switch time, the number of photovoltaic grid-connected switches, the location of photovoltaic grid-connected switches and the sequence of photovoltaic grid-connected switches, and remote operation is achieved according to the intelligent control plan.

2. The intelligent control method based on photovoltaic grid-connected switches according to claim 1 is characterized in that: The steps of obtaining the change of light intensity if photovoltaic grid connection is required and determining the photovoltaic grid connection switch time according to the change of light intensity are specifically as follows: Obtain the changes in light intensity in the photovoltaic power generation area, predict the photovoltaic power generation at different time points based on the changes in light intensity, and form a photovoltaic power generation curve; Obtain historical electricity consumption records, extract electricity load changes based on the historical electricity consumption records, and form an electricity load curve; Set the standard load corresponding to the photovoltaic power generation, and form a corresponding standard load curve according to the photovoltaic power generation curve and the corresponding standard load; Combine the power load curve and the standard load curve to calculate the load difference, set the load difference threshold, and select the time point when the load difference is not greater than the load difference threshold as the standard time point; Standard time points without time intervals are combined to obtain multiple time collections, and the duration of the time collections is counted. The time collections whose duration exceeds a preset duration threshold are used as photovoltaic grid-connected switching time.

3. The intelligent control method based on photovoltaic grid-connected switches according to claim 2 is characterized in that: The steps of obtaining the grid access capability and determining the number of photovoltaic grid-connected switches in combination with the photovoltaic grid-connected switch time and the grid access capability are specifically as follows: The photovoltaic power generation curve corresponding to the photovoltaic grid-connected switching time is extracted and recorded as the grid-connected power generation, and the photovoltaic power generation capacity is extracted based on the grid-connected power generation; The maximum access capacity of the power grid is obtained, and the first number of switches is determined in combination with the photovoltaic power generation capacity; Obtaining the resonance interference intensity, and finding the corresponding second switch quantity according to a preset resonance interference intensity-switch quantity table; The number of photovoltaic grid-connected switches is analyzed by combining the first number of switches and the second number of switches.

4. The intelligent control method based on photovoltaic grid-connected switches according to claim 3 is characterized in that: The step of obtaining the maximum access capacity of the power grid and determining the first number of switches in combination with the photovoltaic power generation capacity is specifically as follows: Determine whether the grid will be overloaded based on the maximum access capacity and photovoltaic power generation capacity; If an overload situation occurs, the average power generation capacity corresponding to the grid-connected switch is calculated, and combined with the maximum access capacity, the threshold value of the number of photovoltaic grid-connected switches is obtained; The average power load is calculated based on the power load curve, and the average power generation corresponding to the grid-connected switch is statistically calculated. The number of standard switches is obtained by combining the average power load and the average power generation; If the number of standard switches is not greater than the threshold number of photovoltaic grid-connected switches, the number of standard switches is used as the first number of switches; If the number of standard switches is greater than the threshold number of photovoltaic grid-connected switches, the threshold number of photovoltaic grid-connected switches is used as the first number of switches; If no overload situation occurs, the standard switch quantity is used as the first switch quantity.

5. The intelligent control method based on photovoltaic grid-connected switches according to claim 4 is characterized in that: The step of analyzing and obtaining the number of photovoltaic grid-connected switches by combining the first number of switches and the second number of switches is specifically as follows: Determine whether the number of the first switches is not less than the number of the second switches. If the number of the first switches is not less than the number of the second switches, use the number of the first switches as the number of photovoltaic grid-connected switches; If the first switch quantity is less than the second switch quantity, determining whether the first switch quantity is a photovoltaic grid-connected switch quantity threshold; If it is the photovoltaic grid-connected switch quantity threshold, the first switch quantity is used as the photovoltaic grid-connected switch quantity; If it is not the photovoltaic grid-connected switch quantity threshold, a quantity weight ratio between the first switch quantity and the second switch quantity is set, and the photovoltaic grid-connected switch quantity is calculated according to the first switch quantity, the second switch quantity and the corresponding quantity weight ratio.

6. The intelligent control method based on photovoltaic grid-connected switches according to claim 5 is characterized in that: The step of obtaining the grid structure of the photovoltaic grid-connected switch and determining the position of the photovoltaic grid-connected switch according to the grid structure and the number of photovoltaic grid-connected switches is specifically as follows: The location of the photovoltaic grid-connected switch is used as the grid-connected point location to form a grid-connected point location map; Obtain the grid structure layout diagram, and obtain the grid area corresponding to the grid connection point according to the grid connection point location diagram and the grid structure layout diagram; Obtain the regional access capacity of the power grid area, obtain the power generation capacity of the grid connection point and record it as the switch power generation capacity, filter out the grid connection points whose switch power generation capacity is greater than the corresponding regional access capacity, and obtain the primary grid connection point; The power generation of the grid-connected point is obtained and recorded as the switch power generation, and the corresponding switch load is obtained according to the switch power generation; Obtaining the regional load of the power grid area, calculating the difference between the switch load and the regional load and recording it as a first difference, setting a first difference threshold, screening and removing primary grid connection points whose first difference is greater than the difference threshold, and obtaining intermediate grid connection points; Evaluate the grid connection success rate and grid connection safety rate of the intermediate grid connection points, set the grid connection weight ratios of the grid connection success rate and the grid connection safety rate respectively, and calculate the grid connection adaptation rate according to the grid connection success rate, the grid connection safety rate and the corresponding grid connection weight ratio; According to the grid-connected adaptation rate, the intermediate grid-connected points are sorted from large to small. According to the number of photovoltaic grid-connected switches, the intermediate grid-connected points with the corresponding number in front of the sorting are selected and recorded as advanced grid-connected points. The switches of the advanced grid-connected points are used as the photovoltaic grid-connected switch positions.

7. The intelligent control method based on photovoltaic grid-connected switches according to claim 6 is characterized in that: The steps of evaluating the grid connection success rate and grid connection safety rate of the intermediate grid connection point are specifically as follows: Acquiring environmental data of the intermediate grid connection point, the environmental data including temperature, humidity and wind speed; The surface temperature of the photovoltaic panel caused by the temperature is obtained, and the reduced temperature of the photovoltaic panel when the wind speed is reduced is obtained according to the wind speed. The surface temperature and the reduced temperature are superimposed to obtain the actual temperature of the photovoltaic panel; Obtaining a temperature threshold that affects power generation performance, determining whether the actual temperature reaches the temperature threshold, and if so, calculating the temperature difference between the actual temperature and the temperature threshold; Obtaining a humidity threshold that affects power generation efficiency, determining whether the humidity reaches the humidity threshold, and if so, calculating a humidity difference between the humidity and the humidity threshold; The difference weight ratios of the temperature difference and the humidity difference are set respectively, and the grid connection success rate is calculated according to the temperature difference, the humidity difference and the corresponding difference weight ratios.

8. The intelligent control method based on photovoltaic grid-connected switches according to claim 7 is characterized in that: The steps of evaluating the grid connection success rate and grid connection safety rate of the intermediate grid connection point are specifically as follows: Obtain a grid access point corresponding to the intermediate grid connection point and record it as the intermediate access point, and obtain the structural solidity of the grid area corresponding to the intermediate access point; Obtain the voltage fluctuation frequency and harmonic content of the generated electric energy at the intermediate grid connection point to evaluate the power quality; The grid stability of the intermediate access point is obtained, and the grid connection safety rate is calculated based on the structural strength and power quality.

9. The intelligent control method based on photovoltaic grid-connected switches according to claim 8, characterized in that: The steps of counting the influence degree of each photovoltaic grid-connected switch after it is turned on according to the position of the photovoltaic grid-connected switch and determining the photovoltaic grid-connected switch sequence according to the influence degree are specifically as follows: Obtain the importance of advanced access points in the grid structure layout; Evaluate the generation capacity of advanced grid connection points based on their generation capacity and generation output; The impact of advanced access points on the power grid is obtained by combining importance and power generation capacity; The order of photovoltaic grid-connected switches is obtained by sorting them according to the degree of impact.

10. An intelligent management and control system based on photovoltaic grid-connected switches, characterized in that: By applying an intelligent control method based on a photovoltaic grid-connected switch according to any one of claims 1 to 9, the method comprises: The grid connection judgment module obtains the grid load and determines whether photovoltaic grid connection is required based on the grid load; The switch time module obtains the change of light intensity if photovoltaic grid connection is required, and determines the photovoltaic grid connection switch time according to the change of light intensity; The switch quantity module obtains the grid access capacity and determines the number of photovoltaic grid-connected switches based on the photovoltaic grid-connected switch time and the grid access capacity; The switch position module obtains the grid structure of the photovoltaic grid-connected switch and determines the position of the photovoltaic grid-connected switch according to the grid structure and the number of photovoltaic grid-connected switches; The switch sequence module counts the impact of each photovoltaic grid-connected switch after it is turned on according to the position of the photovoltaic grid-connected switch, and determines the photovoltaic grid-connected switch sequence according to the impact; The intelligent management and control module forms an intelligent management and control plan for photovoltaic grid-connected switches according to the photovoltaic grid-connected switch time, the number of photovoltaic grid-connected switches, the location of photovoltaic grid-connected switches and the sequence of photovoltaic grid-connected switches, and realizes remote operation according to the intelligent management and control plan.

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