A method for frequency modulation of a photovoltaic power station

Abstract

The application discloses a photovoltaic power station frequency modulation method in the technical field of photovoltaic power stations, which comprises the following steps: S1, acquiring power station parameters of a target photovoltaic power station; S2, obtaining a frequency modulation trigger mechanism according to the photovoltaic parameters; judging a power station operation mode of the target photovoltaic power station according to the frequency modulation trigger mechanism and power grid parameters; S3, if the power station operation mode is a maximum power generation mode, the target photovoltaic power station operates according to the maximum output power; S4, if the power station operation mode is a frequency modulation mode, obtaining power station adjustment power of the target photovoltaic power station according to the power grid parameters and a power grid parameter threshold value; S5, setting a time scale interval, obtaining target power station frequency modulation strategies of the power station adjustment power according to a power adjustment time of the power station adjustment power and the time scale interval; and S6, the target photovoltaic power station performs photovoltaic power station frequency modulation according to the power station adjustment power and the target power station frequency modulation strategies. The application improves the accuracy of photovoltaic power station frequency modulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic power stations, in particular to a photovoltaic power station frequency modulation method. BACKGROUND

[0002] At present, with the global energy structure transforming to clean and low carbon, photovoltaic power generation has continuously increased in installed capacity and grid penetration rate due to its advantages of being clean and renewable, and has become an important power supply type in the power system. However, the output of photovoltaic power generation is significantly affected by natural factors such as solar irradiance, cloud cover, temperature, and precipitation, and has inherent characteristics of intermittency, volatility, and randomness. For example, short-time strong cloud cover can cause the output of the photovoltaic power station to drop sharply in a short time, and after the cloud cover dissipates, the output will quickly rise, and during the night or rainy weather, the photovoltaic output even tends to be zero. This output fluctuation affects the active power supply and demand balance of the photovoltaic power station grid, causing the grid frequency to deviate from the rated value, and when the frequency deviation exceeds the allowed range, it will cause the abnormal operation of the electrical equipment, and even cause the grid to split, large-area power outages, and other major accidents.

[0003] The photovoltaic power station frequency modulation method in the related art often cannot accurately determine whether the photovoltaic power station needs to be frequency modulated according to the power station parameters of the photovoltaic power station, nor can it determine the frequency modulation power value and the frequency modulation mode of the photovoltaic power station according to the power station parameters, resulting in low accuracy of photovoltaic power station frequency modulation. SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a photovoltaic power station frequency modulation method to improve the problem that the photovoltaic power station frequency modulation method in the related art often cannot accurately determine whether the photovoltaic power station needs to be frequency modulated according to the power station parameters of the photovoltaic power station, nor can it determine the frequency modulation power value and the frequency modulation mode of the photovoltaic power station according to the power station parameters, resulting in low accuracy of photovoltaic power station frequency modulation.

[0005] The present application provides a photovoltaic power station frequency modulation method, comprising:

[0006] Step S1: obtaining power station parameters of a target photovoltaic power station, the power station parameters comprising power grid parameters of a power grid in the target photovoltaic power station and photovoltaic parameters of a photovoltaic inverter;

[0007] Step S2: obtaining a frequency modulation trigger mechanism of the target photovoltaic power station according to the analysis of the photovoltaic parameters; comparing and analyzing the frequency modulation trigger mechanism and the power grid parameters to determine and obtain a power station operation mode of the target photovoltaic power station, wherein the power station operation mode comprises a maximum power generation mode and a frequency modulation mode;

[0008] Step S3: if the power station operation mode of the target photovoltaic power station is the maximum power generation mode, the target photovoltaic power station operates according to the maximum output power in the photovoltaic parameters;

[0009] Step S4: If the power station operation mode of the target photovoltaic power station is the frequency modulation mode, the grid parameters are compared and analyzed with the preset grid parameter threshold value, and the power station adjustment power of the target photovoltaic power station is obtained;

[0010] Step S5: A time scale interval is set, and the time scale interval corresponds to an active power supply strategy; a power adjustment time corresponding to the power station adjustment power is obtained, and a target power station frequency modulation strategy of the power station adjustment power is obtained according to the power adjustment time and the time scale interval;

[0011] Step S6: Based on the power station adjustment power and the target power station frequency modulation strategy, the target photovoltaic power station is subjected to photovoltaic power station frequency modulation.

[0012] Further, the power station parameters include grid parameters of a grid in the target photovoltaic power station and photovoltaic parameters of a photovoltaic inverter, and specifically include:

[0013] The photovoltaic parameters include real-time output power and maximum output power; and the grid parameters include a grid frequency change rate and a grid frequency change deviation.

[0014] Further, a frequency modulation triggering mechanism of the target photovoltaic power station is obtained according to the photovoltaic parameters, and specifically includes:

[0015] An output power benchmarking interval is set, and the output power benchmarking interval corresponds to a frequency modulation triggering mechanism;

[0016] The real-time output power of the target photovoltaic power station is compared with the output power benchmarking interval, an output power benchmarking interval corresponding to the real-time output power is obtained, and the frequency modulation triggering mechanism corresponding to the output power benchmarking interval is recorded as the frequency modulation triggering mechanism of the target photovoltaic power station;

[0017] The frequency modulation triggering mechanism includes a grid frequency change rate range, a grid frequency change deviation range, and a change duration threshold value.

[0018] Further, the frequency modulation triggering mechanism and the grid parameters are compared and analyzed to determine and obtain the power station operation mode of the target photovoltaic power station, and specifically includes:

[0019] A change rate duration of the grid frequency change rate in the grid parameters is obtained; and a change deviation duration of the grid frequency change deviation in the grid parameters is obtained;

[0020] If the grid frequency change rate in the grid parameters is within the grid frequency change rate range, and the change rate duration is greater than the change duration threshold value, it is determined that the target photovoltaic power station satisfies a first frequency modulation triggering condition;

[0021] if the grid frequency variation deviation in the grid parameter is within a grid frequency variation deviation range and the variation deviation duration is greater than a variation duration threshold, it is determined that the target photovoltaic power station meets a second frequency modulation triggering condition;

[0022] if the target photovoltaic power station does not meet the first frequency modulation triggering condition and the second frequency modulation triggering condition at the same time, it is determined that the power station operation mode of the target photovoltaic power station is a maximum power generation mode; if the target photovoltaic power station meets the first frequency modulation triggering condition and the second frequency modulation triggering condition at the same time, it is determined that the power station operation mode of the target photovoltaic power station is a frequency modulation mode.

[0023] Further, if the power station operation mode of the target photovoltaic power station is the frequency modulation mode, the grid parameter is compared and analyzed with a preset grid parameter threshold value to obtain the power station adjustment power of the target photovoltaic power station, specifically:

[0024] The grid parameter threshold value includes a grid frequency variation rate threshold value and a grid frequency variation deviation threshold value;

[0025] The grid frequency variation rate in the grid parameter is compared with the frequency variation rate threshold value to obtain the first output power of the target photovoltaic power station; the grid frequency variation deviation in the grid parameter is compared with the frequency variation deviation threshold value to obtain the second output power of the target photovoltaic power station;

[0026] and the power station adjustment power of the target photovoltaic power station is obtained by integrating the first output power and the second output power.

[0027] Further, the grid frequency variation rate in the grid parameter is compared with the frequency variation rate threshold value to obtain the first output power of the target photovoltaic power station, specifically:

[0028] if the grid frequency variation rate of the target photovoltaic power station is less than or equal to the grid frequency variation rate threshold value, the target photovoltaic power station does not need to be first output frequency modulated; if the grid frequency variation rate of the target photovoltaic power station is greater than the frequency variation rate threshold value, the target photovoltaic power station is first output frequency modulated;

[0029] The inertia time constant and the inverter rated capacity of the target photovoltaic power station are obtained, and the first output power of the target photovoltaic power station is obtained according to the product of the inertia time constant, the inverter rated capacity and the grid frequency variation rate;

[0030] When the grid frequency variation rate of the target photovoltaic power station is a negative value, the first output frequency modulation of the target photovoltaic power station is to increase the first output power; when the grid frequency variation rate of the target photovoltaic power station is a positive value, the first output frequency modulation of the target photovoltaic power station is to reduce the first output power.

[0031] Further, the grid frequency variation deviation of the target photovoltaic power station is compared with a grid frequency variation deviation threshold to obtain a second output power of the target photovoltaic power station, specifically:

[0032] If the grid frequency variation deviation of the target photovoltaic power station is less than or equal to the grid frequency variation deviation threshold, the target photovoltaic power station does not need to be second output frequency modulation; if the grid frequency variation deviation of the target photovoltaic power station is greater than the grid frequency variation deviation threshold, the target photovoltaic power station is second output frequency modulation;

[0033] The damping coefficient of the target photovoltaic power station is obtained, and the product of the damping coefficient and the grid frequency variation deviation is obtained to obtain the second output power of the target photovoltaic power station;

[0034] The deviation rated value of the target photovoltaic power station is obtained; if the grid frequency variation deviation of the target photovoltaic power station is less than the deviation rated value, the second output frequency modulation of the target photovoltaic power station is to increase the second output power; if the grid frequency variation deviation of the target photovoltaic power station is greater than the deviation rated value, the second output frequency modulation of the target photovoltaic power station is to reduce the second output power.

[0035] Further, step S5, specifically:

[0036] The target photovoltaic power station includes at least one time scale interval, and the time scale interval also corresponds to an adjustment power category, and the adjustment power category corresponds to a power supply strategy;

[0037] The adjustment power category includes instantaneous adjustment power, sustained adjustment power and long-term adjustment power;

[0038] The power adjustment time is compared with the time scale interval to obtain a time comparison result, and the power adjustment time corresponding to the power adjustment time is divided into an adjustment power category according to the time comparison result, and the adjustment power category corresponding to the power adjustment time is obtained.

[0039] And the power supply strategy corresponding to the adjustment power category is recorded as the target power station frequency modulation strategy of the power adjustment power.

[0040] Further, the power supply strategy corresponding to the adjustment power category is recorded as the target power station frequency modulation strategy of the power adjustment power, specifically:

[0041] If the power adjustment category corresponding to the power adjustment power is instantaneous adjustment power, the power value corresponding to the power adjustment power is output according to the energy storage unit of the target photovoltaic power station;

[0042] If the power adjustment category corresponding to the power adjustment power is sustained adjustment power, the power value corresponding to the power adjustment power is output according to the energy storage unit and the photovoltaic inverter of the target photovoltaic power station.

[0043] If the power adjustment category corresponding to the power station adjustment power is long-term adjustment power, a power value corresponding to the power station adjustment power is output by the photovoltaic inverter of the target photovoltaic power station according to the power station adjustment power.

[0044] Further, the step S6 specifically includes:

[0045] A frequency modulation time corresponding to the power station adjustment power is obtained, and a frequency modulation power trajectory of the target photovoltaic power station is constructed according to the frequency modulation time and the power station adjustment power.

[0046] The target photovoltaic power station is subjected to photovoltaic power station frequency modulation according to the frequency modulation power trajectory and a target power station frequency modulation strategy.

[0047] In summary, the beneficial effects of the present application are as follows: the present application obtains power station parameters of a target photovoltaic power station, the power station parameters including power grid parameters of a power grid in the target photovoltaic power station and photovoltaic parameters of a photovoltaic inverter; a frequency modulation triggering mechanism of the target photovoltaic power station is obtained according to the photovoltaic parameters; and the frequency modulation triggering mechanism is compared and analyzed with the power grid parameters to determine and obtain a power station operation mode of the target photovoltaic power station, wherein the power station operation mode includes a maximum power generation mode and a frequency modulation mode; if the power station operation mode of the target photovoltaic power station is the maximum power generation mode, the target photovoltaic power station operates according to the maximum output power in the photovoltaic parameters; if the power station operation mode of the target photovoltaic power station is the frequency modulation mode, the power grid parameters are compared and analyzed with preset power grid parameter thresholds to obtain a power station adjustment power of the target photovoltaic power station; a time scale interval is set, the time scale interval corresponds to an active power supply strategy; a power adjustment time corresponding to the power station adjustment power is obtained, and a target power station frequency modulation strategy of the power station adjustment power is obtained according to the power adjustment time and the time scale interval; the target photovoltaic power station is subjected to photovoltaic power station frequency modulation according to the power station adjustment power and the target power station frequency modulation strategy, which realizes accurate determination of whether the photovoltaic power station needs to be subjected to frequency modulation according to the power station parameters of the photovoltaic power station, and also enables the determination of a frequency modulation power value and a frequency modulation mode of the photovoltaic power station that needs to be subjected to frequency modulation according to the power station parameters, thereby improving the accuracy of photovoltaic power station frequency modulation. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly set forth the technical solutions of the embodiments of the present application, some of the accompanying drawings in the embodiments of the present application will be briefly described below. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as limiting the scope of the present application.

[0049] Figure 1 A flowchart of a photovoltaic power station frequency modulation method provided by the present application. DETAILED DESCRIPTION

[0050] The embodiments of the present application will be described below in conjunction with the accompanying drawings and specific implementation. Figure 1The application will be further described in detail, but the embodiments of the application are not limited thereto.

[0051] Referring to Figure 1 Fig. 1 is a flow diagram of a photovoltaic power station frequency modulation method according to an embodiment of the application.

[0052] A photovoltaic power station frequency modulation method comprises the following steps:

[0053] Step S1: obtaining power station parameters of a target photovoltaic power station, the power station parameters comprising power grid parameters of a power grid in the target photovoltaic power station and photovoltaic parameters of a photovoltaic inverter;

[0054] Step S2: obtaining a frequency modulation trigger mechanism of the target photovoltaic power station according to the photovoltaic parameters; comparing and analyzing the frequency modulation trigger mechanism and the power grid parameters to determine and obtain a power station operation mode of the target photovoltaic power station, wherein the power station operation mode comprises a maximum power generation mode and a frequency modulation mode;

[0055] Step S3: if the power station operation mode of the target photovoltaic power station is the maximum power generation mode, the target photovoltaic power station operates according to the maximum output power in the photovoltaic parameters;

[0056] Step S4: if the power station operation mode of the target photovoltaic power station is the frequency modulation mode, comparing and analyzing the power grid parameters with preset power grid parameter thresholds to obtain a power station adjustment power of the target photovoltaic power station;

[0057] Step S5: setting time scale intervals, each of which corresponds to an active power supply strategy; obtaining a power adjustment time corresponding to the power station adjustment power, and obtaining a target power station frequency modulation strategy of the power station adjustment power according to the power adjustment time and the time scale intervals;

[0058] Step S6: performing photovoltaic power station frequency modulation on the target photovoltaic power station based on the power station adjustment power and the target power station frequency modulation strategy.

[0059] The power station parameters comprise the power grid parameters of the power grid in the target photovoltaic power station and the photovoltaic parameters of the photovoltaic inverter, and specifically comprise:

[0060] The photovoltaic parameters comprise real-time output power and maximum output power; and the power grid parameters comprise a power grid frequency change rate and a power grid frequency change deviation.

[0061] The frequency modulation trigger mechanism of the target photovoltaic power station is obtained according to the photovoltaic parameters, and specifically comprises:

[0062] An output power benchmark interval is set, each of which corresponds to a frequency modulation trigger mechanism;

[0063] comparing the real-time output power of the target photovoltaic power station with the output power benchmark interval, obtaining the output power benchmark interval corresponding to the real-time output power, and recording the frequency modulation triggering mechanism corresponding to the output power benchmark interval as the frequency modulation triggering mechanism of the target photovoltaic power station;

[0064] The frequency modulation triggering mechanism comprises a grid frequency change rate range, a grid frequency change deviation range, and a change duration threshold.

[0065] In some embodiments, for example, the output power benchmark interval can be set to be greater than or equal to 80% of the rated power or less than or equal to 30% of the rated power, and the rated power can be obtained according to the actual operating parameters of the photovoltaic power station; in actual application, when the output power benchmark interval is greater than or equal to 80% of the rated power, the frequency modulation triggering mechanism can be set to have a grid frequency change rate range in which the absolute value of the grid frequency change rate is greater than 0.02 Hz, a grid frequency change deviation range in which the absolute value of the grid frequency change deviation is greater than 0.1 Hz / s, and a change duration threshold of two grid periods; when the output power benchmark interval is less than or equal to 30% of the rated power, the frequency modulation triggering mechanism can be set to have a grid frequency change rate range in which the absolute value of the grid frequency change rate is greater than 0.07 Hz, a grid frequency change deviation range in which the absolute value of the grid frequency change deviation is greater than 0.5 Hz / s, and a change duration threshold of six grid periods.

[0066] The frequency modulation triggering mechanism and the grid parameters are compared and analyzed to determine and obtain the power station operating mode of the target photovoltaic power station, specifically:

[0067] The change rate duration of the grid frequency change rate in the grid parameters is obtained; the change deviation duration of the grid frequency change deviation in the grid parameters is obtained;

[0068] If the grid frequency change rate in the grid parameters is within the grid frequency change rate range and the change rate duration is greater than the change duration threshold, it is determined that the target photovoltaic power station satisfies the first frequency modulation triggering condition;

[0069] If the grid frequency change deviation in the grid parameters is within the grid frequency change deviation range and the change deviation duration is greater than the change duration threshold, it is determined that the target photovoltaic power station satisfies the second frequency modulation triggering condition;

[0070] If the target photovoltaic power station does not simultaneously satisfy the first frequency modulation triggering condition and the second frequency modulation triggering condition, it is determined that the power station operating mode of the target photovoltaic power station is the maximum power generation mode; if the target photovoltaic power station simultaneously satisfies the first frequency modulation triggering condition and the second frequency modulation triggering condition, it is determined that the power station operating mode of the target photovoltaic power station is the frequency modulation mode.

[0071] In some embodiments, both the change rate duration and the change deviation duration are measured by the grid cycle, such as the change rate duration can be two grid cycles, the change deviation duration can be four grid cycles, etc., and the grid cycle is preset according to the actual operation parameters of the target photovoltaic power station, such as 1h or 2h, etc.

[0072] If the power station operation mode of the target photovoltaic power station is the frequency modulation mode, the grid parameters are compared and analyzed with the preset grid parameter threshold value to obtain the power station adjustment power of the target photovoltaic power station, specifically:

[0073] The grid parameter threshold value includes the grid frequency change rate threshold value and the grid frequency change deviation threshold value;

[0074] The grid frequency change rate in the grid parameters is compared with the frequency change rate threshold value to obtain the first output power of the target photovoltaic power station; and the grid frequency change deviation in the grid parameters is compared with the frequency change deviation threshold value to obtain the second output power of the target photovoltaic power station;

[0075] And the power integration according to the first output power and the second output power obtains the power station adjustment power of the target photovoltaic power station.

[0076] In some embodiments, the inertial response of the target photovoltaic power station is started according to the first output power; and the damping control of the target photovoltaic power station is started according to the second output power, which cooperates with the inertial response;

[0077] The power integration according to the first output power and the second output power means that the first output power and the second output power are added; in addition, if the first output power needs to be increased in actual application, the power value of the first output power is positive, and if the first output power needs to be reduced in actual application, the power value of the first output power is negative; wherein if the second output power needs to be increased in actual application, the power value of the second output power is positive, and if the second output power needs to be reduced in actual application, the power value of the second output power is negative.

[0078] The grid frequency change rate in the grid parameters is compared with the frequency change rate threshold value to obtain the first output power of the target photovoltaic power station, specifically:

[0079] If the grid frequency change rate of the target photovoltaic power station is less than or equal to the grid frequency change rate threshold value, the first output frequency modulation of the target photovoltaic power station is not needed; and if the grid frequency change rate of the target photovoltaic power station is greater than the frequency change rate threshold value, the first output frequency modulation of the target photovoltaic power station is needed;

[0080] Obtaining an inertia time constant and an inverter rated capacity of the target photovoltaic power station, and obtaining a first output power of the target photovoltaic power station according to a product of the inertia time constant, the inverter rated capacity and a grid frequency variation rate;

[0081] When the grid frequency variation rate of the target photovoltaic power station is negative, the first output frequency modulation of the target photovoltaic power station is to increase the first output power; when the grid frequency variation rate of the target photovoltaic power station is positive, the first output frequency modulation of the target photovoltaic power station is to decrease the first output power.

[0082] In some embodiments, the first output power of the target photovoltaic power station can be calculated by a calculation function: first output power = inertia time constant * inverter rated capacity * grid frequency variation rate, wherein the inertia time constant can be taken as 1s, and the inverter rated capacity is obtained according to actual configuration parameters of the photovoltaic inverter; in addition, the first output frequency modulation of the photovoltaic inverter to increase the first output power means to increase the input power value and the input power value is consistent with the value of the first output power; the first output frequency modulation of the photovoltaic inverter to decrease the first output power means to decrease the input power value and the input power value is consistent with the value of the first output power.

[0083] According to comparison between the grid frequency variation deviation in the grid parameter and a frequency variation deviation threshold, a second output power of the target photovoltaic power station is obtained, specifically:

[0084] If the grid frequency variation deviation of the target photovoltaic power station is less than or equal to the grid frequency variation deviation threshold, the second output frequency modulation of the target photovoltaic power station is not needed; if the grid frequency variation deviation of the target photovoltaic power station is greater than the grid frequency variation deviation threshold, the second output frequency modulation of the target photovoltaic power station is needed.

[0085] Obtaining a damping coefficient of the target photovoltaic power station, and obtaining the second output power of the target photovoltaic power station according to a product of the damping coefficient and the grid frequency variation deviation;

[0086] Obtaining a deviation rated value of the target photovoltaic power station; if the grid frequency variation deviation of the target photovoltaic power station is less than the deviation rated value, the second output frequency modulation of the target photovoltaic power station is to increase the second output power; if the grid frequency variation deviation of the target photovoltaic power station is greater than the deviation rated value, the second output frequency modulation of the target photovoltaic power station is to decrease the second output power.

[0087] In some embodiments, the second output power of the target photovoltaic power station can be calculated by a calculation function: second output power = damping coefficient * grid frequency variation deviation; in addition, the second output frequency modulation of the photovoltaic inverter for increasing the second output power means that the input power value is increased and the input power value is consistent with the value of the second output power; the second output frequency modulation of the photovoltaic inverter for decreasing the second output power means that the input power value is decreased and the input power value is consistent with the value of the second output power; in addition, the damping coefficient is generally set to 5-20% S_n / Hz, and the specific value of the damping coefficient can be determined according to the actual demand of the photovoltaic power station grid.

[0088] Step S5, specifically:

[0089] The target photovoltaic power station comprises at least one time scale interval, and the time scale interval further corresponds to an adjustment power category, and the adjustment power category corresponds to a power supply strategy;

[0090] The adjustment power category includes instantaneous adjustment power, sustained adjustment power and long-term adjustment power;

[0091] The power adjustment time is compared with the time scale interval to obtain a time comparison result, and the power adjustment time corresponding to the power adjustment time is divided into an adjustment power category according to the time comparison result, to obtain an adjustment power category corresponding to the power adjustment time of the power station;

[0092] And the power supply strategy corresponding to the adjustment power category is recorded as the target power station frequency modulation strategy of the power adjustment power.

[0093] And the power supply strategy corresponding to the adjustment power category is recorded as the target power station frequency modulation strategy of the power adjustment power, specifically:

[0094] If the power adjustment category corresponding to the power adjustment power is instantaneous adjustment power, the power value corresponding to the power adjustment power is output according to the energy storage unit of the target photovoltaic power station;

[0095] If the power adjustment category corresponding to the power adjustment power is sustained adjustment power, the power value corresponding to the power adjustment power is output according to the energy storage unit and the photovoltaic inverter of the target photovoltaic power station;

[0096] If the power adjustment category corresponding to the power adjustment power is long-term adjustment power, the power value corresponding to the power adjustment power is output according to the photovoltaic inverter of the target photovoltaic power station.

[0097] In some embodiments, the target power station frequency modulation strategy is actually a power supply mode corresponding to the power station adjustment power, and the specific power supply mode is determined by a power adjustment type corresponding to the power station adjustment power. When the power adjustment type corresponding to the power station adjustment power is instantaneous adjustment power, only the energy storage unit supplies the power station adjustment power at this time. When the power adjustment type corresponding to the power station adjustment power is continuous adjustment power, the energy storage unit and the photovoltaic inverter supply the power station adjustment power at this time. When the power adjustment type corresponding to the power station adjustment power is long-term adjustment power, only the photovoltaic inverter supplies the power station adjustment power at this time.

[0098] Step S6, specifically:

[0099] The frequency modulation time corresponding to the power station adjustment power is obtained, and the frequency modulation power trajectory of the target photovoltaic power station is constructed according to the frequency modulation time and the power station adjustment power.

[0100] The photovoltaic power station frequency modulation of the target photovoltaic power station is performed according to the frequency modulation power trajectory and the target power station frequency modulation strategy.

[0101] In some embodiments, the frequency modulation power trajectory is constructed with the frequency modulation time as the horizontal coordinate and the power station adjustment power as the vertical coordinate. The change trend of the power station adjustment frequency with time can be obtained through the frequency modulation power trajectory. The photovoltaic power station frequency modulation of the target photovoltaic power station according to the frequency modulation power trajectory and the target power station frequency modulation strategy means that the power supply of the power station frequency modulation power in the frequency modulation power trajectory within the frequency modulation time is performed through the power supply mode of the target power station frequency modulation strategy, and the frequency modulation of the photovoltaic power station is realized through the power supply.

[0102] The above is only the preferred embodiment of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiments. Any technical solutions falling within the scope of the present application are within the protection scope of the present application. It should be noted that some improvements and refinements made by ordinary skilled in the art without departing from the principles of the present application are also considered to be within the protection scope of the present application.

Claims

1. A method for frequency modulation of a photovoltaic power plant, characterized in that, Comprising: Step S1: obtaining the power station parameters of the target photovoltaic power station, the power station parameters including the grid parameters of the grid in the target photovoltaic power station and the photovoltaic parameters of the photovoltaic inverter; Step S2: obtaining the frequency modulation triggering mechanism of the target photovoltaic power station according to the photovoltaic parameters; and comparing and analyzing the frequency modulation triggering mechanism with the grid parameters to determine and obtain the power station operation mode of the target photovoltaic power station, wherein the power station operation mode includes the maximum power generation mode and the frequency modulation mode; Step S3: if the power station operation mode of the target photovoltaic power station is the maximum power generation mode, the target photovoltaic power station operates according to the maximum output power in the photovoltaic parameters; Step S4: if the power station operation mode of the target photovoltaic power station is the frequency modulation mode, comparing and analyzing the grid parameters with the preset grid parameter threshold to obtain the power station adjustment power of the target photovoltaic power station; Step S5: setting the time scale interval, the time scale interval corresponding to the power supply strategy; obtaining the power adjustment time corresponding to the power station adjustment power, and obtaining the target power station frequency modulation strategy of the power station adjustment power according to the power adjustment time and the time scale interval; Step S6: the target photovoltaic power station performs photovoltaic power station frequency modulation according to the power station adjustment power and the target power station frequency modulation strategy; If the power station operation mode of the target photovoltaic power station is the frequency modulation mode, comparing and analyzing the grid parameters with the preset grid parameter threshold to obtain the power station adjustment power of the target photovoltaic power station, specifically: The grid parameter threshold includes the grid frequency change rate threshold and the grid frequency change deviation threshold; Comparing the grid frequency change rate in the grid parameters with the frequency change rate threshold to obtain the first output power of the target photovoltaic power station; comparing the grid frequency change deviation in the grid parameters with the frequency change deviation threshold to obtain the second output power of the target photovoltaic power station; And integrating the first output power and the second output power to obtain the power station adjustment power of the target photovoltaic power station; Comparing the grid frequency change rate in the grid parameters with the frequency change rate threshold to obtain the first output power of the target photovoltaic power station, specifically: If the grid frequency change rate of the target photovoltaic power station is less than or equal to the grid frequency change rate threshold, the target photovoltaic power station does not need to be first output frequency modulation; if the grid frequency change rate of the target photovoltaic power station is greater than the frequency change rate threshold, the target photovoltaic power station is first output frequency modulation; Obtaining the inertia time constant and the inverter rated capacity of the target photovoltaic power station, and obtaining the first output power of the target photovoltaic power station according to the product of the inertia time constant, the inverter rated capacity and the grid frequency change rate; When the grid frequency change rate of the target photovoltaic power station is negative, the first output frequency modulation of the target photovoltaic power station is to increase the first output power; when the grid frequency change rate of the target photovoltaic power station is positive, the first output frequency modulation of the target photovoltaic power station is to reduce the first output power; Comparing the grid frequency change deviation in the grid parameters with the frequency change deviation threshold to obtain the second output power of the target photovoltaic power station, specifically: If the grid frequency variation deviation of the target photovoltaic power station is less than or equal to the grid frequency variation deviation threshold value, the target photovoltaic power station does not need to be subjected to the second output frequency modulation; if the grid frequency variation deviation of the target photovoltaic power station is greater than the grid frequency variation deviation threshold value, the target photovoltaic power station is subjected to the second output frequency modulation; The damping coefficient of the target photovoltaic power station is obtained, and the second output power of the target photovoltaic power station is obtained according to the product of the damping coefficient and the grid frequency variation deviation; The deviation rated value of the target photovoltaic power station is obtained; if the grid frequency variation deviation of the target photovoltaic power station is less than the deviation rated value, the second output frequency modulation of the target photovoltaic power station is to increase the second output power; if the grid frequency variation deviation of the target photovoltaic power station is greater than the deviation rated value, the second output frequency modulation of the target photovoltaic power station is to reduce the second output power.

2. The method of claim 1, wherein, The power station parameters include grid parameters of a grid in the target photovoltaic power station and photovoltaic parameters of a photovoltaic inverter, and specifically include: The photovoltaic parameters include real-time output power and maximum output power; and the grid parameters include grid frequency variation rate and grid frequency variation deviation.

3. The method of claim 2, wherein the frequency modulation is performed by adjusting the power output of the photovoltaic power station. The frequency modulation triggering mechanism of the target photovoltaic power station is obtained according to the analysis of the photovoltaic parameters, and specifically includes: The output power benchmark interval is set, and the output power benchmark interval corresponds to the frequency modulation triggering mechanism; The real-time output power of the target photovoltaic power station is compared with the output power benchmark interval to obtain the output power benchmark interval corresponding to the real-time output power, and the frequency modulation triggering mechanism corresponding to the output power benchmark interval is recorded as the frequency modulation triggering mechanism of the target photovoltaic power station; The frequency modulation triggering mechanism includes grid frequency variation rate range, grid frequency variation deviation range and variation duration threshold value.

4. The method of claim 3, wherein the frequency modulation of the photovoltaic power station is performed by, The power station operation mode of the target photovoltaic power station is determined and obtained by comparing and analyzing the frequency modulation triggering mechanism and the grid parameters, and specifically includes: The variation duration of the grid frequency variation rate in the grid parameters is obtained; and the variation deviation duration of the grid frequency variation deviation in the grid parameters is obtained; If the grid frequency variation rate in the grid parameters is within the grid frequency variation rate range and the variation duration is greater than the variation duration threshold value, it is determined that the target photovoltaic power station satisfies the first frequency modulation triggering condition; If the grid frequency variation deviation in the grid parameters is within the grid frequency variation deviation range and the variation deviation duration is greater than the variation duration threshold value, it is determined that the target photovoltaic power station satisfies the second frequency modulation triggering condition; If the target photovoltaic power station does not simultaneously satisfy the first frequency modulation triggering condition and the second frequency modulation triggering condition, it is determined that the power station operation mode of the target photovoltaic power station is the maximum power generation mode; if the target photovoltaic power station simultaneously satisfies the first frequency modulation triggering condition and the second frequency modulation triggering condition, it is determined that the power station operation mode of the target photovoltaic power station is the frequency modulation mode.

5. The method of claim 4, wherein, Step S5 specifically includes: The target photovoltaic power station includes at least one time scale interval, and the time scale interval further corresponds to an adjustment power category, and the adjustment power category corresponds to a power supply strategy; The adjustment power category includes instantaneous adjustment power, continuous adjustment power and long-term adjustment power; The power adjustment time is compared with the time scale interval to obtain a time comparison result, and the power adjustment time corresponding power adjustment of the power station is classified according to the adjustment power category according to the time comparison result, to obtain the adjustment power category corresponding to the power adjustment of the power station; And the power supply strategy corresponding to the adjustment power category is recorded as the target power station frequency modulation strategy of the power station adjustment power.

6. The method of claim 5, wherein the frequency modulation of the photovoltaic power station is performed by, And the power supply strategy corresponding to the adjustment power category is recorded as the target power station frequency modulation strategy of the power station adjustment power, specifically: If the power adjustment category corresponding to the power adjustment of the power station is instantaneous adjustment power, the power value corresponding to the power adjustment of the power station is output according to the energy storage unit of the target photovoltaic power station; If the power adjustment category corresponding to the power adjustment of the power station is continuous adjustment power, the power value corresponding to the power adjustment of the power station is output according to the energy storage unit and photovoltaic inverter of the target photovoltaic power station; If the power adjustment category corresponding to the power adjustment of the power station is long-term adjustment power, the power value corresponding to the power adjustment of the power station is output according to the photovoltaic inverter of the target photovoltaic power station.

7. The method of claim 6, wherein the frequency modulation of the photovoltaic power station is performed by, Step S6, specifically: Obtain the frequency modulation time corresponding to the power adjustment of the power station, and construct the frequency modulation power trajectory of the target photovoltaic power station according to the frequency modulation time and the power adjustment of the power station; According to the frequency modulation power trajectory and the target power station frequency modulation strategy, the photovoltaic power station frequency modulation of the target photovoltaic power station is carried out.

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