A variable reserve capacity-based photovoltaic power generation frequency modulation method and system

Abstract

The application provides a variable reserve capacity-based photovoltaic power generation frequency modulation method and system, which comprises the following steps: obtaining historical frequency data; determining the probability distribution of each frequency in each period; generating a probability distribution graph to determine the frequency bimodal characteristic; constructing a frequency modulation reserve capacity function model; determining the first proportion of the real-time maximum available power generation capacity of a photovoltaic power station; setting an adjustment coefficient to construct a reserve capacity correction function model; correcting the first proportion to obtain the second proportion of the real-time maximum available power generation capacity of the photovoltaic power station; determining the frequency modulation reserve capacity of the photovoltaic power station; and using an inverter to adjust the real-time power generation capacity of the photovoltaic power station in real time. The application analyzes the historical frequency of a region to obtain the frequency modulation demand of each period of the day, and calculates the frequency modulation reserve capacity in real time according to the real-time maximum available power generation capacity of the photovoltaic power station, thereby improving the photovoltaic frequency modulation capacity, reducing the waste of reserve capacity, and increasing the photovoltaic power generation capacity.

Description

Technical Field

[0001] This invention relates to the field of power system frequency regulation technology, and more specifically, to a photovoltaic power generation frequency regulation method and system based on variable reserve capacity. Background Technology

[0002] The frequency variation of a region's power grid is related to a variety of factors, such as the frequency regulation performance of each AGC unit in the region, the load characteristics of regional factories and residents, weather, holidays, etc. Analyzing the historical frequency variation signals of a region can help to better regulate the frequency of the regional power grid.

[0003] During normal operation, photovoltaic (PV) power plants reserve a portion of their generating capacity, enabling them to participate in primary frequency regulation. This is one of the main methods for PV power plants to participate in primary frequency regulation. However, the current setting of frequency regulation reserve capacity for PV power plants is rather crude, usually a fixed value (e.g., 10% of the rated capacity) or simply based on changes in sunlight intensity. This makes the frequency regulation capability of PV power plants inflexible and may also result in some electricity not being effectively utilized by the grid. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a photovoltaic power generation frequency regulation method and system based on variable reserve capacity.

[0005] In a first aspect, this disclosure provides a photovoltaic power generation frequency regulation method based on variable reserve capacity, comprising the following steps:

[0006] Obtain historical frequency data for the regional power grid;

[0007] Based on the historical frequency data, determine the probability distribution of each frequency within each period of the historical frequency data;

[0008] A probability distribution map is generated based on the probability distribution to determine the bimodal frequency characteristics;

[0009] Based on the aforementioned frequency bimodal characteristics, a frequency modulation reserve capacity function model is constructed;

[0010] Based on the frequency regulation reserve capacity function model, determine the first proportion of the real-time maximum available power generation of the photovoltaic power station;

[0011] Based on the real-time maximum available power generation of the photovoltaic power plant, an adjustment coefficient is set, and a backup capacity correction function model is constructed.

[0012] The first proportion of the real-time maximum available power generation of the photovoltaic power station is corrected using the reserve capacity correction function model to obtain the second proportion of the real-time maximum available power generation of the photovoltaic power station;

[0013] The frequency regulation reserve capacity of the photovoltaic power station is determined based on a first ratio of the real-time maximum available power generation of the photovoltaic power station to the real-time maximum available power generation of the photovoltaic power station.

[0014] Based on the frequency regulation reserve capacity of the photovoltaic power station, the real-time power generation of the photovoltaic power station is adjusted in real time using an inverter.

[0015] Secondly, this disclosure provides a photovoltaic power generation frequency regulation system based on variable reserve capacity, including a first acquisition unit, a statistical unit, a first processing unit, a first function model construction unit, a first output unit, a second function model construction unit, a second output unit, a second processing unit, and an adjustment unit;

[0016] The first acquisition unit is used to acquire historical frequency data of the regional power grid;

[0017] The statistical unit is used to determine the probability distribution of each frequency in each period of the historical frequency data based on the historical frequency data.

[0018] The first processing unit is configured to generate a probability distribution map based on the probability distribution and determine the frequency bimodal feature;

[0019] The first function model construction unit is used to construct a frequency modulation reserve capacity function model based on the frequency bimodal characteristics;

[0020] The first output unit is used to determine a first proportion of the real-time maximum available power generation of the photovoltaic power station based on the frequency regulation reserve capacity function model.

[0021] The second function model construction unit is used to set the adjustment coefficient and construct the reserve capacity correction function model based on the real-time maximum available power generation of the photovoltaic power station.

[0022] The second output unit is used to correct the first proportion of the real-time maximum available power generation of the photovoltaic power station using the reserve capacity correction function model, so as to obtain the second proportion of the real-time maximum available power generation of the photovoltaic power station.

[0023] The second processing unit is used to determine the frequency regulation reserve capacity of the photovoltaic power station based on a second ratio of the real-time maximum available power generation of the photovoltaic power station to the real-time maximum available power generation of the photovoltaic power station.

[0024] The regulating unit is used to adjust the real-time power generation of the photovoltaic power station using an inverter based on the frequency regulation reserve capacity of the photovoltaic power station.

[0025] The beneficial effects of this invention are: by analyzing the historical frequency of the region, this invention can determine the frequency regulation demand for each time period of the day, and calculate the frequency regulation reserve capacity in real time based on the real-time maximum available power generation of the photovoltaic power station, which can improve the photovoltaic frequency regulation capability, reduce reserve capacity waste, and increase photovoltaic power generation.

[0026] Based on the above technical solution, the present invention can be further improved as follows.

[0027] Furthermore, determining the probability distribution of each frequency within each period of the historical frequency data based on the historical frequency data includes:

[0028] The historical frequency data is classified according to weekdays and holidays to obtain the first category of historical frequency data, and the historical frequency data is classified according to holidays to obtain the second category of historical frequency data.

[0029] The historical frequency data of the first category and the historical frequency data of the second category are statistically analyzed for each day according to a set period to obtain the number of times each frequency occurs in each period.

[0030] Count the number of times each frequency appears in the same period of each day in the historical frequency data of the first category and the historical frequency data of the second category, and generate frequency probability distribution maps of each period of each day for the historical frequency data of the first category and the historical frequency data of the second category.

[0031] The beneficial effect of adopting the above-mentioned further scheme is that by classifying historical frequency data according to weekdays and holidays, frequency probability distribution maps of each cycle of historical frequency data under the two categories of weekdays and holidays are obtained, which helps to better achieve frequency regulation of the regional power grid.

[0032] Furthermore, the step of generating a probability distribution map based on the probability distribution and determining the frequency bimodal feature includes:

[0033] The frequency is divided into a first frequency range and a second frequency range;

[0034] Determine the first frequency value that appears most frequently in the first frequency interval and the second frequency value that appears most frequently in the second frequency interval;

[0035] The frequency bimodal distance is obtained based on the difference between the first frequency value and the second frequency value, and the frequency bimodal distance is used as the value of the frequency bimodal feature.

[0036] The beneficial effect of adopting the above-mentioned further scheme is that by using the probability distribution map to divide the frequency into a first frequency interval and a second frequency interval, it is easier to obtain the frequency bimodal distance as the value of the frequency bimodal feature more accurately.

[0037] Furthermore, the step of constructing a frequency-modulated reserve capacity function model based on the frequency bimodal characteristics includes:

[0038] Obtain the minimum frequency regulation capacity reserved for the photovoltaic power station, the maximum frequency regulation capacity reserved for the photovoltaic power station, and the allowable frequency deviation of the photovoltaic power generation system;

[0039] The frequency deviation is determined based on the bimodal frequency characteristics.

[0040] A frequency warning coefficient is set based on the ratio of the absolute value of the frequency deviation to the allowable frequency deviation of the photovoltaic power generation system.

[0041] A frequency regulation reserve capacity function model is constructed based on the minimum reserved frequency regulation capacity of the photovoltaic power station, the maximum reserved frequency regulation capacity of the photovoltaic power station, the allowable frequency deviation of the photovoltaic power generation system, and the frequency warning coefficient.

[0042] The beneficial effects of adopting the above-mentioned further scheme are that the frequency deviation is obtained based on the frequency bimodal characteristics, and the frequency deviation can accurately reflect the frequency regulation demand at various times of the day; the frequency warning coefficient is set according to the ratio of the frequency deviation to the allowable frequency deviation of the photovoltaic power generation system, which can accurately reflect the sensitivity of the frequency regulation reserve capacity change; and the construction of a frequency regulation reserve capacity function model can improve the photovoltaic frequency regulation effect.

[0043] The step of setting a frequency warning coefficient based on the ratio of the absolute value of the frequency deviation to the absolute value of the allowable frequency deviation of the regional power grid includes:

[0044] Determine the ratio of the highest frequency regulation capacity reserved for photovoltaic power plants to the lowest frequency regulation capacity reserved for photovoltaic power plants;

[0045] The frequency deviation threshold is the threshold value at which the first proportion of the real-time maximum available power generation of the photovoltaic power station is changed by setting the frequency warning coefficient to reach the proportion of the highest frequency regulation capacity reserved by the photovoltaic power station.

[0046] The advantage of adopting the above-mentioned further scheme is that it makes the setting of the frequency warning coefficient accurate and reliable.

[0047] Furthermore, the step of setting an adjustment coefficient and constructing a reserve capacity correction function model based on the real-time maximum available power generation of the photovoltaic power station includes:

[0048] Obtain the real-time maximum available power generation of the photovoltaic power station and the rated power generation of the photovoltaic power station;

[0049] Set adjustment coefficients and construct a reserve capacity correction function model;

[0050] Based on the adjustment coefficient and the rated power generation of the photovoltaic power station, the parameters of the reserve capacity correction function model are determined, and the reserve capacity correction function model is obtained.

[0051] The beneficial effect of adopting the above-mentioned further scheme is that, based on the real-time maximum available power generation of the photovoltaic power station, an adjustment coefficient is set, which can accurately reflect the degree to which the reserve capacity needs to be reduced as the maximum available power generation of the photovoltaic power station increases. Attached Figure Description

[0052] Figure 1 This is a flowchart of a photovoltaic power generation frequency regulation method based on variable reserve capacity in Embodiment 1 of the present invention;

[0053] Figure 2 This is a frequency probability distribution diagram showing the bimodal feature in Embodiment 1 of the present invention;

[0054] Figure 3 This is a frequency probability distribution diagram of the non-bimodal feature in Embodiment 1 of the present invention;

[0055] Figure 4 This is a schematic diagram showing the relationship between the first proportion of the real-time maximum available power generation of the photovoltaic power station and the distance d between the two frequency peaks in Embodiment 1 of the present invention;

[0056] Figure 5 This is a schematic diagram illustrating the relationship between the adjustment coefficient and the real-time maximum available power generation of the photovoltaic power station in Embodiment 1 of the present invention;

[0057] Figure 6 This is a schematic diagram of a photovoltaic power generation frequency regulation system based on variable reserve capacity, provided in Embodiment 2 of the present invention. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0059] Example 1

[0060] This disclosure provides a photovoltaic power generation frequency regulation method based on variable storage capacity, including the following steps:

[0061] Obtain historical frequency data for the regional power grid;

[0062] Based on historical frequency data, determine the probability distribution of each frequency within each period of the historical frequency data.

[0063] Generate a probability distribution map based on the probability distribution to determine the bimodal frequency characteristics;

[0064] Based on the bimodal frequency characteristics, a frequency modulation reserve capacity function model is constructed;

[0065] Based on the frequency regulation reserve capacity function model, determine the first proportion of the real-time maximum available power generation of the photovoltaic power plant;

[0066] Based on the real-time maximum available power generation of the photovoltaic power plant, an adjustment coefficient is set, and a backup capacity correction function model is constructed.

[0067] The first proportion of the real-time maximum available power generation of the photovoltaic power plant is corrected by using the reserve capacity correction function model to obtain the second proportion of the real-time maximum available power generation of the photovoltaic power plant;

[0068] Based on the second proportion of the real-time maximum available power generation of the photovoltaic power station, the frequency regulation reserve capacity of the photovoltaic power station is adjusted in real time using an inverter.

[0069] The beneficial effects of this invention are: by analyzing the historical frequency of the region, this invention can determine the frequency regulation demand for each time period of the day, and calculate the frequency regulation reserve capacity in real time based on the real-time maximum available power generation of the photovoltaic power station, which can improve the photovoltaic frequency regulation capability, reduce reserve capacity waste, and increase photovoltaic power generation.

[0070] Optionally, based on historical frequency data, determine the probability distribution of each frequency within each period of the historical frequency data, including:

[0071] The historical frequency data is classified according to weekdays and holidays. The first category of historical frequency data is obtained by classifying the historical frequency data according to weekdays, and the second category of historical frequency data is obtained by classifying the historical frequency data according to holidays.

[0072] The data for each day of the first category of historical frequency data and the second category of historical frequency data are statistically analyzed according to a set period to obtain the number of times each frequency occurs in each period.

[0073] Count the number of times each frequency appears in the same period of each day in the first category of historical frequency data and the second category of historical frequency data, and generate frequency probability distribution maps for each period of each day in the first category of historical frequency data and the second category of historical frequency data.

[0074] In practical applications, historical frequency data can be optionally divided into weekday data and holiday data. The daily recorded historical frequency data of the power grid is statistically analyzed in 15-minute intervals, resulting in two categories of historical frequency data: weekday historical frequency data and holiday historical frequency data. Each category of frequency data contains 96 time periods within a 24-hour day. Statistical methods are used to analyze these two types of historical data, calculating the probability distribution of different frequencies within each 15-minute interval, thus obtaining the frequency distribution for each data type every 15 minutes. For example, for the weekday data, the frequency records for the first 15 minutes of the past 300 days are summarized in a table, and the frequency probability distribution is obtained through statistical analysis. Similarly, the frequency probability distribution for the nth 15-minute interval on a weekday and the nth 15-minute interval on a holiday are obtained.

[0075] By classifying historical frequency data according to weekdays and holidays, frequency probability distribution maps for each period of the day are obtained for both weekday and holiday scenarios, which helps to better regulate the frequency of the regional power grid.

[0076] Optionally, a probability distribution map is generated based on the probability distribution to determine the bimodal frequency characteristics, including:

[0077] The frequency is divided into a first frequency range and a second frequency range;

[0078] Determine the first frequency value that appears most frequently in the first frequency interval and the second frequency value that appears most frequently in the second frequency interval;

[0079] The frequency bimodal distance is obtained based on the difference between the first frequency value and the second frequency value, and is used as the value of the frequency bimodal characteristic.

[0080] In practical applications, the presence of a bimodal frequency distribution pattern (the distance between the two frequency peaks is greater than 0) is used to determine whether a photovoltaic power generation system requires frequency regulation. If the frequency distribution pattern exhibits a bimodal frequency distribution pattern (i.e., the distance between the two frequency peaks is not 0), see attached... Figure 2 The frequency probability distribution plot shown indicates a bimodal characteristic, with the horizontal axis representing frequency (Hz) and the vertical axis representing the number of times the frequency occurs. This suggests a need for frequency modulation (FM). (See attached image.) Figure 3 The frequency probability distribution plot shown has no bimodal characteristics. The horizontal axis represents frequency (Hz), and the vertical axis represents the number of times the frequency occurs. If the frequency distribution plot does not have bimodal characteristics (i.e., the distance between the two frequency peaks is 0), then there is no need for frequency modulation. Let the distance between the two sampling frequency peaks be d. When the sampling frequency in a certain 15-minute period does not have bimodal characteristics, then d = 0.

[0081] The frequency is divided into a first frequency interval and a second frequency interval. Optionally, the first and second frequency intervals are defined by a frequency point located in the middle of all frequency points in the probability distribution graph. For example, if the first and second frequency intervals are defined by a 50Hz frequency point, then the frequency points in the first frequency interval are to the left of the 50Hz frequency point in the probability distribution graph (i.e., the frequency value of the frequency point in the first frequency interval is less than 50Hz), and the frequency points in the second frequency interval are to the right of the 50Hz frequency point in the probability distribution graph (i.e., the frequency value of the frequency point in the second frequency interval is greater than 50Hz). The frequency point with the highest frequency occurrence in the first frequency interval and the frequency point with the highest frequency occurrence in the second frequency interval are obtained, and the distance d between these two frequency points is calculated to obtain the distance of the frequency bimodal distribution, which is the characteristic value of the frequency bimodal feature. Optionally, it is compared whether the frequency point with the highest frequency occurrence in the first frequency interval and the frequency point with the highest frequency occurrence in the second frequency interval are adjacent frequency points. If they are, then the frequency distribution graph does not have a bimodal feature, and the distance d between the frequency bimodal distributions is 0; otherwise, the frequency distribution graph has a bimodal feature, and the distance d between the frequency bimodal distributions is not 0. In practical applications, when there are multiple maximum frequencies in the first or second frequency range, the frequency with the largest maximum frequency is taken as the peak point of that frequency range, and the distance d between the two frequency peaks is calculated using this peak point.

[0082] By using a probability distribution plot to divide the frequency into a first frequency interval and a second frequency interval, it is easier to obtain the distance between the two frequency peaks as the value of the frequency bimodal feature more accurately.

[0083] Optionally, based on the bimodal frequency characteristics, a frequency modulation reserve capacity function model is constructed, including:

[0084] Obtain the minimum frequency regulation capacity reserved for the photovoltaic power station, the maximum frequency regulation capacity reserved for the photovoltaic power station, and the allowable frequency deviation of the photovoltaic power generation system;

[0085] Determine the frequency deviation based on the bimodal frequency characteristics;

[0086] The frequency warning coefficient is set based on the ratio of the absolute value of the frequency deviation to the allowable frequency deviation of the photovoltaic power generation system.

[0087] A frequency regulation reserve capacity function model is constructed based on the minimum reserved frequency regulation capacity of the photovoltaic power station, the maximum reserved frequency regulation capacity of the photovoltaic power station, the allowable frequency deviation of the photovoltaic power generation system, and the frequency warning coefficient.

[0088] In practical applications, as frequency regulation demands increase, reserve capacity needs to be increased. The bimodal frequency characteristic reflects this demand, so the reserve capacity is set as the first proportion Y(d) of the photovoltaic power plant's real-time maximum available power generation. (Appendix) Figure 4This is a schematic diagram showing the relationship between the first proportion of the real-time maximum available power generation of the photovoltaic power station obtained through experiments and the distance d between the two frequency peaks. The horizontal axis is the distance d between the two frequency peaks (unit: Hz), and the vertical axis is the first proportion Y(d) of the real-time maximum available power generation of the photovoltaic power station.

[0089] In practical applications, the allowable frequency deviation for photovoltaic power generation systems with a capacity of 3000MW and above is ±0.2HZ; for photovoltaic power generation systems with a capacity of less than 3000MW, the allowable frequency deviation is ±0.5HZ. Therefore, let the absolute value of the allowable frequency deviation of the photovoltaic power generation system be B.

[0090] Frequency regulation reserve capacity refers to the proportion of the maximum available power generation of a photovoltaic power plant in real time (for example, a 100MW photovoltaic power plant, under rated operating conditions, has a frequency regulation reserve capacity of 10%, meaning it only generates 90MW of power, and the remaining 10MW of power is reserved as a frequency regulation resource for frequency regulation). It is a piecewise function; the first segment is a monotonically increasing function, and the second segment is a constant function. Let r... min The minimum low-frequency capacity ratio reserved for photovoltaic power plants, r max Given the highest reserved frequency regulation capacity ratio and a frequency warning coefficient of α, the first proportion of the real-time maximum available power generation of the photovoltaic power station is:

[0091]

[0092] Frequency deviation is obtained based on the bimodal frequency characteristics, accurately reflecting the frequency regulation demand at various times of the day. A frequency warning coefficient is set based on the ratio of the frequency deviation to the allowable frequency deviation of the photovoltaic power generation system, accurately reflecting the sensitivity to changes in frequency regulation reserve capacity. Constructing a frequency regulation reserve capacity function model improves the photovoltaic frequency regulation effect. The first proportion Y(d) of the real-time maximum available power generation of the photovoltaic power station is a piecewise function; the highest reserved frequency regulation capacity proportion r of the photovoltaic power station is determined based on the actual engineering situation. max The ratio of the lowest frequency capacity reserved for photovoltaic power plants to r min The first segment of the piecewise function (segment 2αB) can be derived from the point (0, r). min ) and point (2αB, r max ) Determine, (2αB, r max () represents the inflection point of the graph of the first segment of the function (segment 2αB). See attached... Figure 4 As shown, when d = 2αB, the first proportion of the real-time maximum available power generation of the photovoltaic power station reaches the highest frequency regulation capacity ratio r reserved by the photovoltaic power station. max Therefore, the maximum frequency regulation capacity ratio r reserved for the photovoltaic power station can be achieved by adjusting α to change the first segment (segment 2αB) of the piecewise function Y(d). maxThe threshold value of d at that time. Generally, α can be set to 80%, that is, when half of the distance d between the two frequency peaks (0.5d) reaches 80% of the absolute value B of the allowable frequency deviation of the photovoltaic power generation system, the photovoltaic power station needs to use the highest frequency regulation capacity ratio r reserved by the photovoltaic power station. max Reserved capacity for frequency regulation of the power grid in the photovoltaic power station area.

[0093] Optionally, a frequency warning factor is set based on the ratio of the absolute value of the frequency deviation to the absolute value of the allowable frequency deviation of the regional power grid, including:

[0094] Determine the ratio of the highest frequency regulation capacity reserved for photovoltaic power plants to the lowest frequency regulation capacity reserved for photovoltaic power plants;

[0095] The frequency deviation threshold is the threshold value at which the first proportion of the real-time maximum available power generation of the photovoltaic power station is changed by setting the frequency warning coefficient to reach the proportion of the highest frequency regulation capacity reserved by the photovoltaic power station.

[0096] Optionally, based on the real-time maximum available power generation of the photovoltaic power plant, an adjustment coefficient is set, and a reserve capacity correction function model is constructed, including:

[0097] Obtain the real-time maximum available power generation of the photovoltaic power station and the rated power generation of the photovoltaic power station;

[0098] Set adjustment coefficients and construct a reserve capacity correction function model;

[0099] Based on the adjustment coefficient and the rated power generation of the photovoltaic power station, the parameters of the reserve capacity correction function model are determined, and the reserve capacity correction function model is obtained.

[0100] In practical applications, the rated power of photovoltaic (PV) power generation is the power output of a PV power station under optimal conditions such as sunlight and temperature. However, the real-time maximum available power generation of a PV power station is the maximum available power generation at any given moment, under conditions where sunlight and temperature are uncertain. Considering the variation of the maximum available PV power generation over time, the real-time maximum available PV power generation should play a corrective role in determining the reserve capacity. The main purpose of this correction is to increase grid-connected power and improve frequency regulation capabilities. When the real-time maximum available PV power generation is high, the frequency regulation reserve capacity should be reduced; when the real-time maximum available PV power generation is low, the PV frequency regulation reserve capacity should be increased.

[0101] Let P be the real-time maximum available power generation of the photovoltaic power station, P N Let be the rated power output of the photovoltaic power plant, β be the adjustment coefficient, and G(P) be the reserve capacity correction value. Then, the reserve capacity correction function model is:

[0102]

[0103] The adjustment coefficient reflects the degree to which the reserve capacity ratio decreases as the real-time maximum available power generation of the photovoltaic power plant increases.

[0104] As attached Figure 5 The diagram shows the relationship between the adjustment coefficient β and the real-time maximum available power generation of the photovoltaic power station. The horizontal axis represents the maximum available power generation of the photovoltaic power station (unit: MW), and the vertical axis represents the adjustment coefficient.

[0105] As attached Figure 5 As shown, the rated power generation P of the photovoltaic power station N For 10MW, the slope of the G(P) function is from Generally, if the adjustment coefficient β is set to 0.2, then the slope of the G(P) function will be 0.02. If the photovoltaic power station operates at its rated power (i.e., the real-time maximum available power of the photovoltaic power station equals its rated power, P = P0), then... N If G(P) = 80%, then the frequency modulation reserve capacity needs to be reduced by 20%.

[0106] The first proportion of the real-time maximum available power generation of the photovoltaic power station is corrected using a reserve capacity correction function model to obtain the second proportion. In practical applications, let R be the second reserve frequency regulation capacity of the photovoltaic power station, and let Y(d) and G(P) be the product of the second reserve frequency regulation capacity, which is expressed by the following formula:

[0107] R = G(P)Y(d).

[0108] The frequency regulation reserve capacity of the photovoltaic power station is determined based on the second ratio of the real-time maximum available power generation of the photovoltaic power station to the real-time maximum available power generation of the photovoltaic power station.

[0109] Based on the frequency regulation reserve capacity of the photovoltaic power station, the real-time power generation of the photovoltaic power station is adjusted using inverters. After obtaining the reserve frequency regulation capacity R of the photovoltaic power station, a portion of the current maximum available power generation needs to be reserved as frequency regulation reserve capacity. Since the reserve frequency regulation capacity R of the photovoltaic power station is a proportional value, the final reserve power is R×P. Furthermore, the control center of the photovoltaic power station calculates based on the values ​​of R and R×P, and finally issues commands to each inverter, thereby realizing the real-time adjustment of the frequency regulation reserve capacity of the photovoltaic power station.

[0110] Example 2

[0111] Based on the same principle as the method shown in Embodiment 1 of the present invention, as illustrated in the appendix. Figure 6As shown, an embodiment of the present invention also provides a photovoltaic power generation frequency regulation system based on variable reserve capacity, including a first acquisition unit, a statistics unit, a first processing unit, a first function model construction unit, a first output unit, a second function model construction unit, a second output unit, a second processing unit, and an adjustment unit;

[0112] The first acquisition unit is used to acquire historical frequency data of the regional power grid;

[0113] The statistical unit is used to determine the probability distribution of each frequency in each period of the historical frequency data based on the historical frequency data.

[0114] The first processing unit is configured to generate a probability distribution map based on the probability distribution and determine the frequency bimodal feature;

[0115] The first function model construction unit is used to construct a frequency modulation reserve capacity function model based on the frequency bimodal characteristics;

[0116] The first output unit is used to determine a first proportion of the real-time maximum available power generation of the photovoltaic power station based on the frequency regulation reserve capacity function model.

[0117] The second function model construction unit is used to set the adjustment coefficient and construct the reserve capacity correction function model based on the real-time maximum available power generation of the photovoltaic power station.

[0118] The second output unit is used to correct the first proportion of the real-time maximum available power generation of the photovoltaic power station using the reserve capacity correction function model, so as to obtain the second proportion of the real-time maximum available power generation of the photovoltaic power station.

[0119] The second processing unit is used to determine the frequency regulation reserve capacity of the photovoltaic power station based on a second ratio of the real-time maximum available power generation of the photovoltaic power station to the real-time maximum available power generation of the photovoltaic power station.

[0120] The regulating unit is used to adjust the real-time power generation of the photovoltaic power station using an inverter based on the frequency regulation reserve capacity of the photovoltaic power station.

[0121] Optionally, the statistical unit includes a classification unit, a statistical unit, and a generation unit;

[0122] The classification unit is used to classify historical frequency data according to weekdays and holidays. Classifying historical frequency data according to weekdays yields the first category of historical frequency data, and classifying historical frequency data according to holidays yields the second category of historical frequency data.

[0123] The statistical unit is used to perform statistical analysis on the daily data of the first category of historical frequency data and the second category of historical frequency data according to a set period, and to obtain the number of times each frequency occurs in each period.

[0124] The generation unit is used to count the number of times each frequency appears in the same period of each day in the first category of historical frequency data and the second category of historical frequency data, and to generate frequency probability distribution maps of each period of each day for the first category of historical frequency data and the second category of historical frequency data.

[0125] Optionally, the processing unit includes: a partitioning unit, a first determining unit, and a second determining unit;

[0126] A dividing unit is used to divide the frequency into a first frequency range and a second frequency range;

[0127] The first determining unit is used to determine the first frequency value that appears most frequently in the first frequency interval and the second frequency value that appears most frequently in the second frequency interval.

[0128] The second determining unit is used to obtain the frequency bi-peak distance based on the difference between the first frequency value and the second frequency value, and to use the frequency bi-peak distance as the value of the frequency bi-peak feature.

[0129] Optionally, the first function model construction unit includes: a second acquisition unit, a third determination unit, a setting unit, and a first function model construction subunit;

[0130] The second acquisition unit is used to acquire the minimum frequency regulation capacity reserved by the photovoltaic power station, the maximum frequency regulation capacity reserved by the photovoltaic power station, and the allowable frequency deviation of the photovoltaic power generation system.

[0131] The third determining unit is used to determine the frequency deviation based on the bi-peak frequency characteristics.

[0132] The setting unit is used to set the frequency warning coefficient based on the ratio of the absolute value of the frequency deviation to the allowable frequency deviation of the photovoltaic power generation system.

[0133] The first function model construction subunit is used to construct a frequency regulation reserve capacity function model based on the minimum reserved frequency regulation capacity of the photovoltaic power station, the maximum reserved frequency regulation capacity of the photovoltaic power station, the allowable frequency deviation of the photovoltaic power generation system, and the frequency warning coefficient.

[0134] Optionally, the setting unit includes:

[0135] The fourth determining unit is used to determine the ratio of the highest frequency regulation capacity reserved for the photovoltaic power station to the lowest frequency regulation capacity reserved for the photovoltaic power station.

[0136] A subunit is configured to set a threshold value for the frequency deviation when the first proportion of the real-time maximum available power generation of the photovoltaic power station is changed by setting the frequency warning coefficient to reach the highest frequency regulation capacity proportion reserved by the photovoltaic power station. Optionally, the second function model construction unit includes a third acquisition unit, a second function model construction subunit, and a calculation and processing unit.

[0137] The third acquisition unit is used to acquire the real-time maximum available power generation of the photovoltaic power station and the rated power generation of the photovoltaic power station;

[0138] The second function model construction sub-unit is used to set the adjustment coefficient and construct the standby capacity correction function model.

[0139] The calculation and processing unit is used to determine the parameters of the reserve capacity correction function model based on the adjustment coefficient and the rated power generation of the photovoltaic power station, and to obtain the reserve capacity correction function model.

[0140] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A photovoltaic power generation frequency regulation method based on variable reserve capacity, characterized in that, Includes the following steps: Obtain historical frequency data for the regional power grid; Based on the historical frequency data, determine the probability distribution of each frequency within each period of the historical frequency data; Generate a probability distribution map based on the probability distribution, and determine the frequency bimodal feature, including: dividing the frequency into a first frequency interval and a second frequency interval; determining the first frequency value with the highest frequency occurrence in the first frequency interval and the second frequency value with the highest frequency occurrence in the second frequency interval; obtaining the frequency bimodal distance based on the difference between the first frequency value and the second frequency value, and using the frequency bimodal distance as the value of the frequency bimodal feature; Based on the aforementioned frequency bimodal characteristics, a frequency modulation reserve capacity function model is constructed; Based on the frequency regulation reserve capacity function model, determine the first proportion of the real-time maximum available power generation of the photovoltaic power station; Based on the real-time maximum available power generation of the photovoltaic power plant, an adjustment coefficient is set, and a backup capacity correction function model is constructed. The first proportion of the real-time maximum available power generation of the photovoltaic power station is corrected using the reserve capacity correction function model to obtain the second proportion of the real-time maximum available power generation of the photovoltaic power station; The frequency regulation reserve capacity of the photovoltaic power station is determined based on the second ratio of the real-time maximum available power generation of the photovoltaic power station to the real-time maximum available power generation of the photovoltaic power station. Based on the frequency regulation reserve capacity of the photovoltaic power station, the real-time power generation of the photovoltaic power station is adjusted in real time using an inverter.

2. The photovoltaic power generation frequency regulation method based on variable reserve capacity according to claim 1, characterized in that, Determining the probability distribution of each frequency within each period of the historical frequency data based on the historical frequency data includes: The historical frequency data is classified according to weekdays and holidays to obtain the first category of historical frequency data, and the historical frequency data is classified according to holidays to obtain the second category of historical frequency data. The historical frequency data of the first category and the historical frequency data of the second category are statistically analyzed for each day according to a set period to obtain the number of times each frequency occurs in each period. Count the number of times each frequency appears in the same period of each day in the historical frequency data of the first category and the historical frequency data of the second category, and generate frequency probability distribution maps of each period of each day for the historical frequency data of the first category and the historical frequency data of the second category.

3. The photovoltaic power generation frequency regulation method based on variable reserve capacity according to claim 1, characterized in that, The step of constructing a frequency modulation reserve capacity function model based on the frequency bimodal characteristics includes: Obtain the minimum frequency regulation capacity reserved for the photovoltaic power station, the maximum frequency regulation capacity reserved for the photovoltaic power station, and the allowable frequency deviation of the photovoltaic power generation system; The frequency deviation is determined based on the bimodal frequency characteristics. A frequency warning coefficient is set based on the ratio of the absolute value of the frequency deviation to the allowable frequency deviation of the photovoltaic power generation system. A frequency regulation reserve capacity function model is constructed based on the minimum reserved frequency regulation capacity of the photovoltaic power station, the maximum reserved frequency regulation capacity of the photovoltaic power station, the allowable frequency deviation of the photovoltaic power generation system, and the frequency warning coefficient.

4. The photovoltaic power generation frequency regulation method based on variable reserve capacity according to claim 3, characterized in that, The step of setting a frequency warning coefficient based on the ratio of the absolute value of the frequency deviation to the absolute value of the allowable frequency deviation of the regional power grid includes: Determine the ratio of the highest frequency regulation capacity reserved for photovoltaic power plants to the lowest frequency regulation capacity reserved for photovoltaic power plants; The frequency deviation threshold is the threshold value at which the first proportion of the real-time maximum available power generation of the photovoltaic power station is changed by setting the frequency warning coefficient to reach the proportion of the highest frequency regulation capacity reserved by the photovoltaic power station.

5. The photovoltaic power generation frequency regulation method based on variable reserve capacity according to claim 1, characterized in that, The process of setting adjustment coefficients and constructing a reserve capacity correction function model based on the real-time maximum available power generation of the photovoltaic power station includes: Obtain the real-time maximum available power generation of the photovoltaic power station and the rated power generation of the photovoltaic power station; Set adjustment coefficients and construct a reserve capacity correction function model; Based on the adjustment coefficient and the rated power generation of the photovoltaic power station, the parameters of the reserve capacity correction function model are determined, and the reserve capacity correction function model is obtained.

6. A photovoltaic power generation frequency regulation system based on variable reserve capacity, characterized in that, It includes a first acquisition unit, a statistics unit, a first processing unit, a first function model construction unit, a first output unit, a second function model construction unit, a second output unit, a second processing unit, and an adjustment unit; The first acquisition unit is used to acquire historical frequency data of the regional power grid; The statistical unit is used to determine the probability distribution of each frequency in each period of the historical frequency data based on the historical frequency data. The first processing unit is configured to generate a probability distribution map based on the probability distribution and determine the frequency bimodal feature, including: dividing the frequency into a first frequency interval and a second frequency interval; determining a first frequency value that occurs most frequently in the first frequency interval and a second frequency value that occurs most frequently in the second frequency interval; obtaining the frequency bimodal distance based on the difference between the first frequency value and the second frequency value, and using the frequency bimodal distance as the value of the frequency bimodal feature; The first function model construction unit is used to construct a frequency modulation reserve capacity function model based on the frequency bimodal characteristics; The first output unit is used to determine a first proportion of the real-time maximum available power generation of the photovoltaic power station based on the frequency regulation reserve capacity function model. The second function model construction unit is used to set the adjustment coefficient and construct the reserve capacity correction function model based on the real-time maximum available power generation of the photovoltaic power station. The second output unit is used to correct the first proportion of the real-time maximum available power generation of the photovoltaic power station using the reserve capacity correction function model, so as to obtain the second proportion of the real-time maximum available power generation of the photovoltaic power station. The second processing unit is used to determine the frequency regulation reserve capacity of the photovoltaic power station based on a second ratio of the real-time maximum available power generation of the photovoltaic power station to the real-time maximum available power generation of the photovoltaic power station. The regulating unit is used to adjust the real-time power generation of the photovoltaic power station using an inverter based on the frequency regulation reserve capacity of the photovoltaic power station.

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