Grid-connected control method and system of distributed power supply

Abstract

The invention relates to the technical field of electric power automation, and particularly discloses a grid-connected control method and system for a distributed power supply, and the method comprises the steps: generating a multi-dimensional power grid state data set according to the real-time power grid operation data after the grid connection of the distributed power supply, and calculating a power grid stability index according to a first data set; if the power grid stability index is greater than a preset stability threshold value, calculating a power grid output power target value according to the second data set; judging whether the grid connection point of the distributed power supply has voltage transient drop or not, and calculating an output power compensation value of the distributed power supply according to the amplitude of the voltage transient drop and the rated output power of the distributed power supply when the voltage transient drop exists; if the voltage transient drop does not exist, adjusting the output power of the power grid based on the target value of the output power of the power grid; and if the voltage transient drop exists, adjusting the power grid output power based on the power grid output power target value, and adjusting the output power of the distributed power supply based on the output power compensation value.

Description

Technical Field

[0001] This application relates to the field of power automation technology, and particularly to a grid connection control method and system for distributed power sources. Background Art

[0002] With the rapid development of power automation technology, the automatic control, monitoring, dispatching, and optimization of power systems have become the key to ensuring the efficient, safe, and stable operation of power supply. In this field, the grid connection control method for distributed power sources is particularly crucial, which directly affects the stability, flexibility, and economy of the power grid when accommodating distributed power sources. Distributed power sources, such as renewable energy power generation systems like solar and wind energy, have been widely used in recent years due to their environmental protection and sustainable characteristics. However, the grid connection process of distributed power sources faces many technical challenges.

[0003] Traditional grid connection control methods for power sources show obvious limitations when dealing with the grid connection of distributed power sources. These methods often rely on fixed operating parameter adjustment strategies and lack the ability to process real-time and comprehensive grid operation data. Therefore, in the face of load changes, traditional methods often cannot accurately predict and respond in a timely manner, resulting in frequent problems such as grid voltage fluctuations and current instability. These problems not only affect the power quality but also reduce the overall performance and stability of the power system. Therefore, in the context of large-scale access of distributed power sources to the power grid, traditional grid connection control methods are difficult to meet the stability and reliability requirements of the power system. Summary of the Invention

[0004] In view of this, this application provides a grid connection control method and system for distributed power sources, a storage medium, and a computer device. By measures such as obtaining real-time grid operation data, performing time series aggregation, evaluating grid stability, calculating the target value of grid output power, and coping with voltage transient dips, it realizes timely and accurate response after the grid connection of distributed power sources, greatly reduces the occurrence of problems such as grid voltage fluctuations and current instability, and helps to improve the stability and reliability of the power grid.

[0005] According to one aspect of this application, a grid connection control method for distributed power sources is provided, including: After the distributed power source is connected to the grid, obtain real-time grid operation data, perform time series aggregation on the real-time grid operation data to generate a multi-dimensional grid state data set, and calculate a grid stability index according to a first data set in the multi-dimensional grid state data set, where the first data set includes the aggregated grid instantaneous voltage, grid frequency fluctuation, and grid load change rate; If the power grid stability index is greater than a preset stability threshold, then based on the second data set in the multi-dimensional power grid state data set, calculate the load difference between the actual load demand of the power grid at the current moment and the conventional load of the power grid, and calculate the change rate of the power grid load demand at the current moment. Based on the load difference, the change rate of the power grid load demand, and the output power of the power grid at the current moment, calculate the target value of the power grid output power, where the second data set includes the aggregated actual load demand of the power grid and the output power of the power grid; and, determine whether there is a voltage transient dip at the distributed power source connection point, and when there is a voltage transient dip, calculate the output power compensation value of the distributed power source according to the voltage transient dip amplitude and the rated output power of the distributed power source; In the case where there is no voltage transient dip at the distributed power source connection point, adjust the power grid output power based on the target value of the power grid output power; In the case where there is a voltage transient dip at the distributed power source connection point, adjust the power grid output power based on the target value of the power grid output power, and adjust the output power of the distributed power source based on the output power compensation value of the distributed power source.

[0006] According to another aspect of the present application, there is provided a grid connection control system for a distributed power source, including: A real-time data acquisition module, configured to, after the distributed power source is connected to the grid, acquire real-time power grid operation data, perform time series aggregation on the real-time power grid operation data to generate a multi-dimensional power grid state data set, and calculate a power grid stability index according to the first data set in the multi-dimensional power grid state data set, where the first data set includes the aggregated instantaneous voltage of the power grid, the power grid frequency fluctuation, and the change rate of the power grid load; A calculation module, configured to, if the power grid stability index is greater than a preset stability threshold, then based on the second data set in the multi-dimensional power grid state data set, calculate the load difference between the actual load demand of the power grid at the current moment and the conventional load of the power grid, and calculate the change rate of the power grid load demand at the current moment. Based on the load difference, the change rate of the power grid load demand, and the output power of the power grid at the current moment, calculate the target value of the power grid output power, where the second data set includes the aggregated actual load demand of the power grid and the output power of the power grid; and, determine whether there is a voltage transient dip at the distributed power source connection point, and when there is a voltage transient dip, calculate the output power compensation value of the distributed power source according to the voltage transient dip amplitude and the rated output power of the distributed power source; An adjustment module, configured to adjust the grid output power based on the grid output power target value when there is no voltage transient dip at the grid connection point of the distributed power source; when there is a voltage transient dip at the grid connection point of the distributed power source, adjust the grid output power based on the grid output power target value, and adjust the output power of the distributed power source based on the output power compensation value of the distributed power source.

[0007] According to another aspect of the present application, there is provided a storage medium, on which a computer program is stored, and when the program is executed by a processor, the grid connection control method of the distributed power source described above is implemented.

[0008] According to still another aspect of the present application, there is provided a computer device, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, and when the processor executes the program, the grid connection control method of the distributed power source described above is implemented.

[0009] By the above technical solution, a grid connection control method and system, a storage medium, and a computer device for a distributed power source provided by the present application can, after the distributed power source is connected to the grid, first obtain real-time grid operation data, and then perform time series aggregation on these real-time grid operation data to generate a multi-dimensional grid state data set. Among them, the multi-dimensional grid state data set can include a first data set and a second data set. The first data set includes the aggregated grid instantaneous voltage, grid frequency fluctuation, and grid load change rate. Then, the grid stability index can be calculated according to the first data set. Compare the calculated grid stability index with a preset stability threshold. If the grid stability index is greater than the preset stability threshold, it indicates that the grid is in an unstable state. At this time, the second data set can be selected from the multi-dimensional grid state data set, and the load difference between the actual grid load demand and the grid conventional load at the current moment, as well as the change rate of the grid load demand, can be calculated according to the second data set. Here, the second data set includes the aggregated actual grid load demand and grid output power. Subsequently, based on the load difference, the grid load demand change rate, and the grid output power at the current moment, the target value of the grid output power is calculated. In addition, it can also be determined whether there is a voltage transient dip at the distributed power source grid connection point. When a voltage transient dip is detected, the output power compensation value of the distributed power source is calculated according to the amplitude of the voltage transient dip and the rated output power of the distributed power source. If there is no voltage transient dip at the distributed power source grid connection point, the grid output power is adjusted based on the target value of the grid output power to ensure the stable operation of the grid; if there is a voltage transient dip at the distributed power source grid connection point, not only the grid output power needs to be adjusted based on the target value of the grid output power, but also the output power of the distributed power source needs to be adjusted based on the output power compensation value of the distributed power source to ensure the stable operation of the grid and the effective utilization of the distributed power source at the same time. Through measures such as obtaining real-time grid operation data, performing time series aggregation, evaluating grid stability, calculating the target value of grid output power, and coping with voltage transient dips, the embodiments of the present application achieve timely and accurate response after the distributed power source is connected to the grid, greatly reducing the occurrence of grid voltage fluctuations and current instability problems, and helping to improve the stability and reliability of the grid.

[0010] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically exemplified below. Brief Description of the Drawings

[0011] The accompanying drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings: Figure 1 A schematic flowchart of a grid connection control method for a distributed power source provided by an embodiment of the present application is shown; Figure 2 A schematic structural diagram of a grid connection control system for a distributed power source provided by an embodiment of the present application is shown; Figure 3 A schematic structural diagram of a device of a computer device provided by an embodiment of the present application is shown. Detailed implementation manners

[0012] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other.

[0013] In this embodiment, a grid connection control method for a distributed power source is provided. As Figure 1 shown, the method includes: Step 101: After the distributed power source is connected to the grid, obtain real-time grid operation data, perform time series aggregation on the real-time grid operation data to generate a multi-dimensional grid state data set, and calculate a grid stability index according to a first data set in the multi-dimensional grid state data set, where the first data set includes the aggregated grid instantaneous voltage, grid frequency fluctuation, and grid load change rate.

[0014] A grid connection control method for a distributed power source provided by an embodiment of the present application can automatically adjust the operation condition of the power grid after the distributed power source is connected to the grid to ensure the stability of the power grid operation after the distributed power source is connected to the grid. After the distributed power source is connected to the grid, first, real-time power grid operation data can be obtained. Here, the real-time power grid operation data can include the maximum grid voltage, the minimum grid voltage, the grid frequency, the grid load, the actual load demand of the power grid, the grid output power, etc. These data can be collected by real-time sensors or recorded by a monitoring system, and each data can be associated with a timestamp and can be obtained immediately after collection. Then, time series aggregation can be performed on these real-time power grid operation data to generate a multi-dimensional power grid state data set. The purpose of time series aggregation is to organize a large amount of real-time data into a multi-dimensional power grid state data set that is easier to analyze and process, so as to reduce the complexity of the data and highlight key information. Among them, the multi-dimensional power grid state data set can include a first data set and a second data set. The first data set includes the aggregated instantaneous grid voltage, the grid frequency fluctuation, and the grid load change rate. Then, a power grid stability index can be calculated according to the first data set. This index is a comprehensive index used to evaluate the stability degree of the power grid in the current state.

[0015] Step 102, if the power grid stability index is greater than a preset stability threshold, then according to the second data set in the multi-dimensional power grid state data set, calculate the load difference between the actual load demand of the power grid and the conventional load of the power grid at the current moment and calculate the change rate of the power grid load demand at the current moment. According to the load difference, the change rate of the power grid load demand, and the grid output power at the current moment, calculate the target value of the grid output power. Among them, the second data set includes the aggregated actual load demand of the power grid and the grid output power; and, determine whether there is a voltage transient dip at the distributed power source grid connection point, and when there is a voltage transient dip, calculate the output power compensation value of the distributed power source according to the voltage transient dip amplitude and the rated output power of the distributed power source.

[0016] In this embodiment, the calculated power grid stability index is compared with a preset stability threshold. If the power grid stability index is greater than the preset stability threshold, it indicates that the power grid is in an unstable state and further adjustment measures can be taken. In the case of an unstable power grid, the second data set can be selected from the multi-dimensional power grid state data set, and according to the second data set, calculate the load difference between the actual load demand of the power grid and the conventional load of the power grid at the current moment, and the change rate of the power grid load demand. Here, the second data set includes the aggregated actual load demand of the power grid and the grid output power. Subsequently, based on the load difference, the change rate of the power grid load demand, and the grid output power at the current moment, calculate the target value of the grid output power. This target value aims to make the power grid operate more stably while meeting the load demand.

[0017] In addition, it is also possible to determine whether there is a voltage transient dip at the connection point of the distributed power source. A voltage transient dip refers to the phenomenon that the grid voltage suddenly drops within a short period of time, which can pose a threat to the stable operation of the grid. When a voltage transient dip is detected, according to the amplitude of the voltage transient dip and the rated output power of the distributed power source, the output power compensation value of the distributed power source is calculated. This compensation value is designed to reduce the impact of the voltage transient dip on the grid by adjusting the output power of the distributed power source.

[0018] It should be noted that when the calculated grid stability index is less than or equal to the preset stability threshold, it indicates that the grid is in a stable state and adjustment measures can be temporarily not taken.

[0019] Step 103, in the case where there is no voltage transient dip at the connection point of the distributed power source, based on the grid output power target value, adjust the grid output power.

[0020] Step 104, in the case where there is a voltage transient dip at the connection point of the distributed power source, based on the grid output power target value, adjust the grid output power, and, based on the output power compensation value of the distributed power source, adjust the output power of the distributed power source.

[0021] In this embodiment, if there is no voltage transient dip at the connection point of the distributed power source, the grid output power is adjusted based on the target value of the grid output power to ensure the stable operation of the grid; if there is a voltage transient dip at the connection point of the distributed power source, not only the grid output power needs to be adjusted based on the target value of the grid output power, but also the output power of the distributed power source needs to be adjusted based on the output power compensation value of the distributed power source to ensure the stable operation of the grid and the effective utilization of the distributed power source at the same time.

[0022] By applying the technical solution of this embodiment, after the distributed power source is connected to the grid, first, real-time grid operation data can be obtained. Then, time series aggregation can be performed on these real-time grid operation data to generate a multi-dimensional grid state data set. Among them, the multi-dimensional grid state data set can include a first data set and a second data set. The first data set includes the aggregated grid instantaneous voltage, grid frequency fluctuation, and grid load change rate. Then, a grid stability index can be calculated according to the first data set. The calculated grid stability index is compared with a preset stability threshold. If the grid stability index is greater than the preset stability threshold, it indicates that the grid is in an unstable state. At this time, the second data set can be selected from the multi-dimensional grid state data set, and the load difference between the actual grid load demand and the grid conventional load at the current moment, as well as the change rate of the grid load demand, can be calculated according to the second data set. Here, the second data set includes the aggregated actual grid load demand and grid output power. Subsequently, based on the load difference, the grid load demand change rate, and the grid output power at the current moment, the target value of the grid output power is calculated. In addition, it can also be determined whether there is a voltage transient dip at the distributed power source connection point. When a voltage transient dip is detected, the output power compensation value of the distributed power source is calculated according to the amplitude of the voltage transient dip and the rated output power of the distributed power source. If there is no voltage transient dip at the distributed power source connection point, the grid output power is adjusted based on the target value of the grid output power to ensure the stable operation of the grid; if there is a voltage transient dip at the distributed power source connection point, not only the grid output power needs to be adjusted based on the target value of the grid output power, but also the output power of the distributed power source needs to be adjusted based on the output power compensation value of the distributed power source to simultaneously ensure the stable operation of the grid and the effective utilization of the distributed power source. Through measures such as obtaining real-time grid operation data, performing time series aggregation, evaluating grid stability, calculating the target value of grid output power, and coping with voltage transient dips, the embodiments of this application achieve timely and accurate response after the distributed power source is connected to the grid, greatly reducing the occurrence of grid voltage fluctuations and current instability problems, and helping to improve the stability and reliability of the grid.

[0023] In the embodiment of this application, optionally, in step 101, the "calculating a grid stability index according to the first data set in the multi-dimensional grid state data set" includes: aligning the aggregated grid instantaneous voltage, grid frequency fluctuation, and grid load change rate in the first data set according to the time dimension, and calculating the grid stability index according to the alignment result; Among them, the grid stability index is calculated based on the following formula: ; S represents the grid stability index, represents the weighting coefficient of the grid instantaneous voltage, represents the aggregated instantaneous grid voltage represents the weighted coefficient of grid frequency fluctuation represents the aggregated grid frequency fluctuation represents the weighted coefficient of grid load change rate represents the aggregated grid load change rate. Z represents the number of aggregation segments of the grid instantaneous voltage, z represents the index of the aggregated grid instantaneous voltage data item, m represents the number of aggregation segments of the grid frequency fluctuation, j represents the index of the aggregated grid frequency fluctuation data item, p represents the number of aggregation segments of the grid load change rate, and k represents the index of the aggregated grid load change rate data item.

[0024] In this embodiment, aligning according to the time dimension can ensure that the data used to calculate the grid stability index is data from the same time period. The number of aggregation segments refers to the total number of each aggregated data corresponding to a certain time period. For example, assuming to calculate the grid stability index for the time period from 12:00 to 13:00, within this time period, there are n groups of aggregated grid instantaneous voltages, m groups of aggregated grid frequency fluctuations, and t groups of aggregated grid load change rates. Here, n, m, and t are the "number of aggregation segments". The weighted coefficients of the grid instantaneous voltage, the weighted coefficients of the grid frequency fluctuation, and the weighted coefficients of the grid load change rate can be determined according to actual needs, and for the same type of weighted coefficient, the corresponding values for different numbers of aggregation segments can be different. The result of the grid stability index represents the stability status of the current overall grid operation. The higher the value, the greater the grid stability risk, and regulation is required to reduce the risk and ensure the safe and stable operation of the grid. The smaller the value, the better the grid stability.

[0025] Among them, : the weighted coefficient of the grid instantaneous voltage, representing the influence weight of voltage fluctuation on grid stability and reflecting the sensitivity of voltage fluctuation to grid stability; : the maximum value of the instantaneous voltage fluctuation within the aggregation time period, representing the most severe degree of voltage fluctuation within this time period; : the weighted coefficient of the grid frequency fluctuation, representing the influence weight of grid frequency fluctuation on grid stability; : the maximum amplitude of the grid frequency fluctuation within the aggregation time period, representing the most severe degree of frequency fluctuation within this time period; : the weighted coefficient of the grid load change rate, representing the influence weight of grid load change rate on grid stability; : the maximum value of the grid load change rate within the aggregation time period, representing the most severe degree of grid load change within this time period.

[0026] In an embodiment of the present application, optionally, the real-time grid operation data includes the maximum grid voltage, the minimum grid voltage, the grid frequency, the grid load, the actual grid load demand, and the grid output power; in step 101, the "performing time series aggregation on the real-time grid operation data to generate a multi-dimensional grid state data set" includes: calculating the average grid voltage based on the maximum grid voltage and the minimum grid voltage at the current sampling moment, and using the average grid voltage as the instantaneous grid voltage at the current sampling moment; calculating the difference between the grid frequency at the current sampling moment and the standard grid frequency, and using the absolute value of the difference as the grid frequency fluctuation at the current sampling moment; calculating the load difference between the grid load at the current sampling moment and the grid load at the previous sampling moment, and calculating the first ratio between the load difference and the grid load at the previous sampling moment, and using the first ratio as the grid load change rate at the current sampling moment; dividing the instantaneous grid voltage, the grid frequency fluctuation, the grid load change rate, the actual grid load demand, and the grid output power corresponding to each sampling moment according to a preset time interval to obtain an instantaneous grid voltage set, a grid frequency fluctuation set, a grid load change rate set, an actual grid load demand set, and a grid output power set corresponding to each preset time interval; for each preset time interval, determining the maximum instantaneous voltage from the instantaneous grid voltage set, determining the maximum frequency fluctuation from the grid frequency fluctuation set, and determining the maximum load change rate from the grid load change rate set, and using the maximum instantaneous voltage, the maximum frequency fluctuation, and the maximum load change rate as the first aggregation result corresponding to the preset time interval, and arranging the first aggregation results corresponding to each preset time interval in chronological order to obtain a first data set; and respectively calculating the average values of the actual grid load demand set and the grid output power set, and using the average value of the actual grid load demand and the average value of the grid output power as the second aggregation result corresponding to the preset time interval, and arranging the second aggregation results corresponding to each preset time interval in chronological order to obtain a second data set.

[0027] In this embodiment, the real-time grid operation data may include the maximum grid voltage, the minimum grid voltage, the grid frequency, the grid load, the actual grid load demand, the grid output power, etc. at each sampling moment.

[0028] Assume that the maximum grid voltage at a certain sampling moment is , and the minimum grid voltage is , then the instantaneous grid voltage is : ; The grid frequency fluctuation is the monitoring of the grid frequency change. Assume that the grid frequency at a certain sampling moment is , the standard grid frequency is , then the grid frequency fluctuation is which is: ; The grid load change rate reflects the change rate of the grid load. Assume that the grid load at a certain sampling moment is , and the grid load at the previous sampling moment is , then the grid load change rate is which is: ; After obtaining the grid instantaneous voltage, grid frequency fluctuation, and grid load change rate corresponding to each sampling moment, further, at preset time intervals, the grid instantaneous voltage, grid frequency fluctuation, grid load change rate, grid actual load demand, and grid output power can be grouped. The sampling time length corresponding to each group is equal to the preset time interval, and the sampling times between groups do not overlap, and then multiple groups can be obtained. In this way, a grid instantaneous voltage set, a grid frequency fluctuation set, a grid load change rate set, a grid actual load demand set, and a grid output power set corresponding to each preset time interval can be obtained. Assume that the preset time interval is 5 minutes, then the grid instantaneous voltage, grid frequency fluctuation, grid load change rate, grid actual load demand, and grid output power are aggregated every 5 minutes. The goal of the aggregation process is to calculate a statistical value representing the grid state in each time period by processing the values in each time period. The aggregated data provides necessary statistical features for subsequent grid stability analysis.

[0029] For each preset time interval, subsequently, on the one hand, the maximum instantaneous voltage can be determined from the grid instantaneous voltage set, the maximum frequency fluctuation can be determined from the grid frequency fluctuation set, and the maximum load change rate can be determined from the grid load change rate set. The maximum instantaneous voltage, maximum frequency fluctuation, and maximum load change rate are used as the first aggregation result corresponding to this preset time interval. Arranging the first aggregation results corresponding to each preset time interval in chronological order can obtain the first data set.

[0030] On the other hand, calculate the average value of the grid actual load demand set to obtain the average value of the grid actual load demand, and calculate the average value of the grid output power set to obtain the average value of the grid output power. The average value of the grid actual load demand and the average value of the grid output power are used as the second aggregation result corresponding to the preset time interval. Arranging the second aggregation results corresponding to each preset time interval in chronological order can obtain the second data set.

[0031] In an embodiment of the present application, optionally, the step 102 of "calculating the load difference between the actual grid load demand at the current moment and the normal grid load and calculating the grid load demand change rate at the current moment according to the second data set in the multi-dimensional grid state data set, and calculating the target value of the grid output power according to the load difference, the grid load demand change rate, and the grid output power at the current moment" includes: calculating the load difference between the actual grid load demand at the current moment and the normal grid load according to the second data set in the multi-dimensional grid state data set; when the absolute value of the load difference is greater than a preset difference threshold, calculating the grid load demand change rate at the current moment based on the actual grid load demand at the current moment and the actual grid load demand at the previous moment, and calculating the product of the grid output power at the current moment and the grid load demand change rate, and taking the difference between the grid output power at the current moment and the product result as the target value of the grid output power.

[0032] In this embodiment, first, extract the actual grid load demand at the current moment from the second data set in the multi-dimensional grid state data set, and obtain the normal grid load. Among them, the normal grid load can be the average value of historical grid load data. Then, calculate the load difference between the actual grid load demand at the current moment and the normal grid load. This load difference reflects the deviation degree between the current grid load and the normal load. As shown in the following formula: ; Wherein, is the absolute value of the load difference, is the actual grid load demand at the current moment, is the normal grid load.

[0033] Next, compare the absolute value of the calculated load difference with the preset difference threshold. Among them, the preset difference threshold is a preset threshold used to determine whether the load difference is significant enough to require adjustment measures. If the absolute value of the load difference is greater than the preset difference threshold, it means that the current grid load deviates greatly from the normal load, then it can be considered that the load fluctuates, and the grid output power can be adjusted to meet the load demand. At this time, obtain the actual grid load demand at the current moment and the actual grid load demand at the previous moment. Based on these two data points, calculate the grid load demand change rate at the current moment. This change rate reflects the change trend of the grid load demand in a short period of time. Specifically, the actual grid load demand at the current moment can be subtracted from the actual grid load demand at the previous moment, and the obtained value is divided by the actual grid load demand at the previous moment, and the quotient obtained is the grid load demand change rate at the current moment.

[0034] After that, multiply the grid output power at the current moment by the change rate of the grid load demand to obtain a product result. This product result reflects the trend that the grid output power should be adjusted with the change of the load demand. Further, take the difference between the grid output power at the current moment and this product result as the target value of the grid output power. This target value aims to enable the grid output power to adapt to the change of the load demand while maintaining the stable operation of the grid. The embodiment of the present application realizes the dynamic adjustment of the grid output power, which helps to improve the flexibility and response speed of the grid, enables the grid to better adapt to the change of the load demand, and thus ensures the stable operation and reliable power supply of the grid.

[0035] In the embodiment of the present application, optionally, in step 102, the "calculating the output power compensation value of the distributed power source according to the voltage transient drop amplitude and the rated output power of the distributed power source" includes: calculating the voltage difference between the normal grid voltage and the voltage after the grid voltage drop at the current moment, and calculating the second ratio between the voltage difference and the normal grid voltage, and taking the second ratio as the voltage transient drop amplitude; determining a matching drop amplitude classification coefficient based on the voltage transient drop amplitude; calculating the product of the rated output power of the distributed power source and the drop amplitude classification coefficient, and taking the product result as the output power compensation value of the distributed power source.

[0036] In this embodiment, first, obtain the voltage value of the grid in the normal state and the actual voltage value of the grid after the voltage drop at the current moment. The difference between these two voltage values is the voltage difference. Then, dividing this voltage difference by the normal grid voltage can obtain the second ratio, and this second ratio can be taken as the voltage transient drop amplitude. The voltage transient drop amplitude refers to the degree of the grid voltage drop in a short time, which is caused by power equipment failures, system load fluctuations or other factors. The voltage transient drop amplitude reflects the severity of the voltage drop and is a value between 0 and 1. For example, assume that the normal grid voltage is 220V and the voltage after the voltage drop is 200V, then the voltage difference is 20V, and the voltage transient drop amplitude is (20 / 220)×100% = 9.09%.

[0037] Subsequently, according to the calculated voltage transient dip amplitude, look up the corresponding dip amplitude classification coefficient that matches it from a preset correspondence or table. This coefficient can be preset based on experience and grid stability requirements, and different dip amplitude ranges correspond to different coefficient values. For example, assume that a voltage transient dip amplitude less than 5% is a minor dip, between 5% and 10% is a moderate dip, and greater than 10% is a severe dip. Then, there can be different dip amplitude classification coefficients corresponding to minor dips, moderate dips, and severe dips respectively. The purpose of the dip amplitude classification coefficient is to convert the severity of the voltage dip into specific guidance for adjusting the output power of the distributed power source.

[0038] After obtaining the dip amplitude classification coefficient, then multiply it by the rated output power of the distributed power source. The rated output power is the maximum power that the distributed power source can continuously output under standard conditions. The result of the multiplication is the output power compensation value of the distributed power source under the current voltage transient dip condition. This value indicates how much the output power of the distributed power source needs to be increased or decreased to help the grid cope with the challenges brought by the voltage dip and maintain the stable operation of the grid.

[0039] The embodiment of this application determines how to adjust the output power of the distributed power source by calculating the voltage transient dip amplitude and using the preset dip amplitude classification coefficient, aiming to ensure that when the grid encounters a voltage transient dip (i.e., a sudden voltage drop), the distributed power source can appropriately adjust its output power to assist in maintaining the stability of the grid. This method helps to improve the flexibility and stability of the grid. Especially in the face of emergencies, it can make more effective use of distributed power source resources to ensure the continuity and reliability of power supply.

[0040] In the embodiment of this application, optionally, after step 104, the method further includes: real-time monitoring of the phase sequence characteristics of the connection point of the distributed power source, calculating the phase sequence difference between the phase sequence characteristics of the connection point of the distributed power source and the phase sequence characteristics of the grid to obtain phase sequence difference data; calculating a harmonic impact evaluation value through a grid harmonic interference level evaluation formula; obtaining a harmonic impact evaluation result based on the phase sequence difference data and the harmonic impact evaluation value, and when the harmonic impact evaluation result triggers a harmonic impedance adjustment condition, calculating a harmonic impedance adjustment value of the distributed power source through a harmonic impedance adjustment formula, and adjusting the harmonic impedance of the distributed power source based on the harmonic impedance adjustment value.

[0041] In this embodiment, after adjusting the output power of the distributed power source, further, the process of monitoring and evaluating the impact of the distributed power source connection point on the grid harmonics can be carried out, and the harmonic impedance of the distributed power source can be adjusted according to the evaluation result to reduce the adverse impact of harmonics on the grid. Specifically, first, the phase sequence characteristics of the distributed power source connection point are monitored in real time. Monitoring the phase sequence characteristics can help understand whether the voltage phase of the distributed power source connection point is normal and whether there are problems such as phase offset. Then, the phase sequence difference between the phase sequence characteristics of the distributed power source connection point and the grid phase sequence characteristics is calculated. Specifically, the difference between the phase sequence characteristics (such as phase angle, etc.) of the distributed power source connection point and the grid standard phase sequence characteristics can be compared, and then the phase sequence difference data can be obtained. If the phase sequence characteristics of the grid are inconsistent with the phase sequence characteristics of the power source output, it may lead to phase disorder, and then cause damage to power equipment or power quality problems. When analyzing the phase sequence difference between the phase sequence characteristics of the distributed power source connection point and the grid phase sequence characteristics, the voltage waveform data of the grid and the output voltage waveform data of the distributed power source can be obtained, and the voltage waveforms of each phase are measured. Generally, the voltage waveform data of the grid can be obtained by sensors, and the output voltage waveform data of the distributed power source can be monitored in real time through a power analyzer. By comparing the voltage waveforms of the three phases of the grid with the voltage waveforms of the three phases of the distributed power source output, check whether the waveforms of each phase appear at the maximum value or zero crossing point at the same time. If a phase sequence difference is found, the following calculation formula is used to quantify the difference and obtain the phase sequence difference data: ; Wherein, represents the phase sequence difference data, represents the grid phase sequence characteristics (such as phase angle); represents the phase sequence characteristics (such as phase angle) of the distributed power source connection point.

[0042] Next, use the power grid harmonic interference level evaluation formula to calculate the harmonic impact evaluation value. This evaluation value reflects the severity of the harmonic interference of the distributed power source connection point on the power grid. Harmonic interference may be generated by the distributed power source itself or by other devices in the power grid. Subsequently, based on the phase sequence difference data and the harmonic impact evaluation value, comprehensively judge the degree of the harmonic impact of the distributed power source connection point on the power grid to obtain the harmonic impact evaluation result. If the harmonic impact evaluation result triggers the harmonic impedance adjustment condition (such as the harmonic impact evaluation value exceeding the preset impact threshold and / or the phase sequence difference exceeding the allowable range), then harmonic impedance adjustment is required. At this time, the harmonic impedance adjustment formula can be used to calculate the harmonic impedance adjustment value. This adjustment value represents the amount of harmonic impedance that needs to be increased or decreased to improve the harmonic impact of the distributed power source connection point on the power grid. Finally, based on the calculated harmonic impedance adjustment value, adjust the harmonic impedance of the distributed power source. Specifically, it can be achieved by changing the output filter of the distributed power source, adjusting the control strategy of the converter, etc.

[0043] In the embodiment of the present application, by real-time monitoring the phase sequence characteristics and harmonic impact of the distributed power source connection point, potential harmonic problems can be discovered and corrected in a timely manner; by adjusting the harmonic impedance of the distributed power source, the adverse effects of harmonics on the power grid can be reduced, and the stability and reliability of the power grid can be improved.

[0044] In the embodiment of the present application, optionally, the power grid harmonic interference level evaluation formula is as follows:

[0045] where THD represents the harmonic impact evaluation value, represents the amplitude of the th harmonic component, represents the amplitude of the fundamental wave, represents the voltage amplitude of the distributed power source, represents the total harmonic distortion of the power grid, represents the total harmonic distortion of the distributed power source, represents the output current of the distributed power source, represents the maximum number of times of harmonic analysis, represents the number of the harmonic currently being analyzed; The harmonic impedance adjustment formula is as follows: ; where represents the harmonic impedance adjustment value of the distributed power source.

[0046] In this embodiment, can be obtained through Fourier transform (FFT) or a harmonic analyzer; The output voltage of the distributed power source can be measured directly or obtained by calculating the fundamental component through FFT; It can be directly obtained through a voltage measuring device; It can be obtained through a harmonic detection device on the grid side; It can be obtained through a power analyzer or a power quality monitoring device; It can be measured through a current sensor or a smart meter; N can be set according to the requirements of harmonic analysis accuracy.

[0047] Among them, represents the harmonic impact evaluation value, which is used to indicate the total harmonic distortion between the power grid and the distributed power source and evaluate the harmonic interference level of the power grid; can represent the intensity of different frequency components.

[0048] Assume that the fundamental amplitude of the power grid = 230V, the amplitude of the 2nd harmonic = 10V, the amplitude of the 3rd harmonic = 5V, the amplitude of the 4th harmonic = 2V, the total harmonic distortion of the power grid = 5.08%, the total harmonic distortion of the distributed power source = 4.5%, the output current of the distributed power source = 15A, the voltage amplitude of the distributed power source = 220V; Substitute the parameters into the formula for calculation: ; ; ; ; The result of 0.42% indicates that the total harmonic distortion between the power grid and the distributed power source is low, meaning that the harmonic interference between the power grid and the distributed power source is small, and the matching degree of the output waveform of the distributed power source and the power grid is good.

[0049] Adjusting the harmonic impedance of the distributed power source can optimize the harmonic matching degree between the output waveform of the distributed power source and the power grid waveform. The purpose of adjusting the harmonic impedance of the distributed power source is to reduce the harmonic mismatch with the power grid by changing the output characteristics of the distributed power source, thereby reducing the harmonic interference of the distributed power source to the power grid. Assume that the voltage amplitude V of the distributed power source source is 220V, the output current I of the distributed power source source is 10A, the total harmonic distortion THD of the power grid grid = 5.08%, the total harmonic distortion THD of the distributed power source source = 4.5%, then the calculated value of the harmonic impedance adjustment is: ; Therefore, the harmonic impedance of the distributed power source needs to be adjusted by 0.128 Ω.

[0050] In an embodiment of the present application, optionally, after "adjusting the harmonic impedance of the distributed power source based on the harmonic impedance adjustment value", the method further includes: calculating a grid output power change rate corresponding to the current moment based on the aggregated grid output power in the second dataset, and calculating a grid load demand change rate corresponding to the current moment based on the aggregated actual grid load demand in the second dataset; calculating a change rate difference between the grid load demand change rate and the grid output power change rate corresponding to the current moment, and if the change rate difference is greater than the power matching deviation threshold, obtaining the output power of the distributed power source at the current moment and the predicted grid load demand, and calculating a power demand difference; splitting the power demand difference according to a preset adjustment stage to obtain a power adjustment plan, and adjusting the output power of the distributed power source according to the power adjustment plan.

[0051] In this embodiment, after adjusting the harmonic impedance of the distributed power source based on the harmonic impedance adjustment value, the output power of the distributed power source is further dynamically adjusted according to the changes in the grid output power and the load demand. Specifically, first, the aggregated grid output power processed through aggregation is obtained from the second dataset. According to the aggregated grid output power, the grid output power change rate corresponding to the current moment is calculated. The grid output power change rate can be determined by calculating the difference between the grid output power at the current moment and the grid output power at the previous moment, and then calculating the ratio of this difference to the grid output power at the previous moment. It should be noted that the moment here refers to the aggregated moment after aggregation processing. For example, if the sampling moment is every minute and the preset time interval is 5 minutes, then the aggregated moment is every 5 minutes as an aggregated moment.

[0052] Similarly, the aggregated actual grid load demand processed through aggregation is obtained from the second dataset. According to the aggregated actual grid load demand, the grid load demand change rate corresponding to the current moment is calculated. The grid load demand change rate can be determined by calculating the difference between the actual grid load demand at the current moment and the actual grid load demand at the previous moment, and then calculating the ratio of this difference to the actual grid load demand at the previous moment.

[0053] Next, calculate the rate difference between the change rate of the grid load demand corresponding to the current moment and the change rate of the grid output power. This difference reflects the degree of mismatch between the grid output power and the load demand. If the rate difference is greater than the preset power matching deviation threshold, it indicates that there is a large mismatch between the grid output power and the load demand, and adjustment is required. After confirming the need for adjustment, obtain the output power of the distributed power source at the current moment and the predicted load demand of the grid. The predicted load demand can be obtained by predicting based on factors such as historical data, weather forecasts, and holiday information. Then, calculate the power demand difference between the current output power of the distributed power source and the predicted load demand of the grid. This difference represents the amount of output power that the distributed power source needs to increase or decrease to meet the grid load demand. Split the calculated power demand difference according to the preset adjustment stages to obtain a power adjustment plan. This plan usually includes multiple adjustment stages, each corresponding to a certain time range and power adjustment amount. Finally, adjust the output power of the distributed power source according to the power adjustment plan. During the adjustment process, the changes in the grid output power and load demand can be monitored in real time to ensure that the output power of the adjusted distributed power source matches the grid load demand.

[0054] In the embodiment of the present application, by monitoring and analyzing the changes in the grid output power and load demand in real time, the power mismatch problem between the distributed power source and the grid can be discovered and corrected in a timely manner. By formulating and implementing a power adjustment plan, it is possible to ensure that the output power of the distributed power source matches the grid load demand, improving the stability and reliability of the grid.

[0055] In the embodiment of the present application, optionally, the step of "splitting the power demand difference according to the preset adjustment stages to obtain a power adjustment plan" includes: splitting the power demand difference according to the preset adjustment stages to obtain the sub-difference corresponding to each adjustment stage; determining the maximum power adjustment amplitude of each historical adjustment stage based on the historical power adjustment plan; for each adjustment stage, updating the sub-difference within the adjustment stage based on the maximum power adjustment amplitude, and generating a power adjustment plan based on the updated results of each adjustment stage.

[0056] In this embodiment, the power adjustment plan can be generated according to the following steps. First, according to the actual requirements and time plan, determine the preset adjustment phases of the power adjustment plan. These phases can be fixed time intervals (such as every hour, every half day, every day, etc.), or time periods based on specific events or conditions. Then, split the total power demand difference according to these preset adjustment phases. For example, evenly distribute the total power demand difference to each phase, or make a more refined distribution according to the expected load change in each phase. After distribution, each adjustment phase will have a corresponding sub-difference, indicating the amount of power that needs to be adjusted within that phase. To formulate a reasonable power adjustment plan, historical data of past similar power adjustment plans and their implementation results can also be collected, and these historical data can be analyzed, especially focusing on the maximum power adjustment amplitude in each historical adjustment phase. The maximum power adjustment amplitude refers to the maximum value of the actual adjustment of the distributed power output power within a certain phase. Subsequently, based on the analysis results of the historical data, determine the maximum power adjustment amplitude in each historical adjustment phase. This helps to understand the adjustment ability that the distributed power can achieve in actual operation and provides a reference for formulating a new power adjustment plan. Then, for each new adjustment phase, update the sub-difference obtained by splitting based on the determined maximum power adjustment amplitude. If the sub-difference exceeds the maximum power adjustment amplitude of this phase, adjust it to the maximum power adjustment amplitude; if the sub-difference is small, keep it unchanged or make fine-tuning as needed. Combine the updated results of each adjustment phase to form a complete power adjustment plan. This plan can detail the amount of power that needs to be adjusted in each adjustment phase, as well as the expected adjustment time and method.

[0057] The embodiment of the present application ensures the rationality and feasibility of the power adjustment plan through steps such as splitting the power demand difference, analyzing historical data, updating the sub-difference, and formulating the power adjustment plan. This method helps to achieve the dynamic adjustment and optimization of the distributed power output power while ensuring the stability of the power grid.

[0058] Further, as Figure 1 a specific implementation of the method, the embodiment of the present application provides a grid-connected control system for a distributed power source, which is applied to the grid-connected control method of the distributed power source as described in any one of the above, as Figure 2 shown, the system includes: A real-time data acquisition module, which is used to obtain real-time power grid operation data after the distributed power source is grid-connected, perform time series aggregation on the real-time power grid operation data to generate a multi-dimensional power grid state data set, and calculate a power grid stability index according to the first data set in the multi-dimensional power grid state data set, where the first data set includes the aggregated grid instantaneous voltage, grid frequency fluctuation, and grid load change rate; A calculation module, configured to, if the power grid stability index is greater than a preset stability threshold, calculate a load difference between the actual load demand of the power grid at the current moment and the conventional load of the power grid and calculate the power grid load demand change rate at the current moment according to a second data set in the multi-dimensional power grid state data set, and calculate a target value of the power grid output power according to the load difference, the power grid load demand change rate, and the power grid output power at the current moment, where the second data set includes the aggregated actual load demand of the power grid and the power grid output power; and determine whether there is a voltage transient dip at the distributed power source connection point, and when there is a voltage transient dip, calculate an output power compensation value of the distributed power source according to the voltage transient dip amplitude and the rated output power of the distributed power source; An adjustment module, configured to, in the case where there is no voltage transient dip at the distributed power source connection point, adjust the power grid output power based on the target value of the power grid output power; in the case where there is a voltage transient dip at the distributed power source connection point, adjust the power grid output power based on the target value of the power grid output power, and adjust the output power of the distributed power source based on the output power compensation value of the distributed power source.

[0059] Optionally, the real-time data acquisition module is configured to: Align the aggregated grid instantaneous voltage, grid frequency fluctuation, and grid load change rate in the first data set according to the time dimension, and calculate the power grid stability index according to the alignment result; Wherein, the power grid stability index is calculated based on the following formula: ; S represents the power grid stability index, represents the weighting coefficient of the grid instantaneous voltage, represents the aggregated grid instantaneous voltage, represents the weighting coefficient of the grid frequency fluctuation, represents the aggregated grid frequency fluctuation, represents the weighting coefficient of the grid load change rate, represents the aggregated grid load change rate, Z represents the number of aggregation segments of the grid instantaneous voltage, z represents the index of the aggregated grid instantaneous voltage data item, m represents the number of aggregation segments of the grid frequency fluctuation, j represents the index of the aggregated grid frequency fluctuation data item, p represents the number of aggregation segments of the grid load change rate, and k represents the index of the aggregated grid load change rate data item.

[0060] Optionally, the real-time power grid operation data includes the maximum power grid voltage, the minimum power grid voltage, the power grid frequency, the power grid load, the actual load demand of the power grid, and the power grid output power; the real-time data acquisition module is further configured to: Calculate the average grid voltage based on the maximum grid voltage and the minimum grid voltage at the current sampling moment, and use the average grid voltage as the instantaneous grid voltage at the current sampling moment; Calculate the difference between the grid frequency at the current sampling moment and the standard grid frequency, and use the absolute value of the difference as the grid frequency fluctuation at the current sampling moment; Calculate the load difference between the grid load at the current sampling moment and the grid load at the previous sampling moment, and calculate the first ratio between the load difference and the grid load at the previous sampling moment, and use the first ratio as the grid load change rate at the current sampling moment; Divide the instantaneous grid voltage, grid frequency fluctuation, grid load change rate, actual grid load demand, and grid output power corresponding to each sampling moment according to a preset time interval to obtain an instantaneous grid voltage set, a grid frequency fluctuation set, a grid load change rate set, an actual grid load demand set, and a grid output power set corresponding to each preset time interval; For each preset time interval, determine the maximum instantaneous voltage from the instantaneous grid voltage set, determine the maximum frequency fluctuation from the grid frequency fluctuation set, and determine the maximum load change rate from the grid load change rate set, and use the maximum instantaneous voltage, the maximum frequency fluctuation, and the maximum load change rate as the first aggregation result corresponding to the preset time interval, and arrange the first aggregation results corresponding to each preset time interval in chronological order to obtain a first data set; and, calculate the average values of the actual grid load demand set and the grid output power set respectively, and use the average value of the actual grid load demand and the average value of the grid output power as the second aggregation result corresponding to the preset time interval, and arrange the second aggregation results corresponding to each preset time interval in chronological order to obtain a second data set.

[0061] Optionally, the calculation module is configured to: Calculate the load difference between the actual grid load demand at the current moment and the conventional grid load according to the second data set in the multi-dimensional grid state data set; When the absolute value of the load difference is greater than a preset difference threshold, calculate the grid load demand change rate at the current moment based on the actual grid load demand at the current moment and the actual grid load demand at the previous moment, and calculate the product of the grid output power at the current moment and the grid load demand change rate, and use the difference between the grid output power at the current moment and the product result as the grid output power target value.

[0062] Optionally, the calculation module is further configured to: Calculate the voltage difference between the normal grid voltage and the voltage after the grid voltage sag at the current moment, and calculate the second ratio between the voltage difference and the normal grid voltage, and use the second ratio as the voltage transient sag amplitude; Based on the voltage transient sag amplitude, determine the matching sag amplitude classification coefficient; Calculate the product between the rated output power of the distributed power source and the sag amplitude classification coefficient, and use the product result as the output power compensation value of the distributed power source.

[0063] Optionally, the adjustment module is further configured to: After adjusting the output power of the distributed power source, monitor the phase sequence characteristics of the connection point of the distributed power source in real time, and calculate the phase sequence difference between the phase sequence characteristics of the connection point of the distributed power source and the grid phase sequence characteristics to obtain phase sequence difference data; Calculate the harmonic influence evaluation value through the grid harmonic interference level evaluation formula; According to the phase sequence difference data and the harmonic influence evaluation value, obtain the harmonic influence evaluation result, and when the harmonic influence evaluation result triggers the harmonic impedance adjustment condition, calculate the harmonic impedance adjustment value of the distributed power source through the harmonic impedance adjustment formula, and adjust the harmonic impedance of the distributed power source based on the harmonic impedance adjustment value.

[0064] Optionally, the grid harmonic interference level evaluation formula is as follows:

[0065] where THD represents the harmonic influence evaluation value, represents the amplitude of the th harmonic component, represents the amplitude of the fundamental wave, represents the voltage amplitude of the distributed power source, represents the total harmonic distortion of the grid, represents the total harmonic distortion of the distributed power source, represents the output current of the distributed power source, represents the maximum number of times of harmonic analysis, represents the number of times of the harmonic being analyzed currently; The harmonic impedance adjustment formula is as follows: ; where, represents the harmonic impedance adjustment value of the distributed power source.

[0066] Optionally, the adjustment module is further configured to: After adjusting the harmonic impedance of the distributed power source based on the harmonic impedance adjustment value, calculate the grid output power change rate corresponding to the current moment based on the aggregated grid output power in the second dataset, and calculate the grid load demand change rate corresponding to the current moment based on the aggregated actual grid load demand in the second dataset; Calculate the change rate difference between the grid load demand change rate and the grid output power change rate corresponding to the current moment. If the change rate difference is greater than the power matching deviation threshold, obtain the output power of the distributed power source at the current moment and the predicted grid load demand, and calculate the power demand difference; Split the power demand difference according to a preset adjustment stage to obtain a power adjustment plan, and adjust the output power of the distributed power source according to the power adjustment plan.

[0067] Optionally, the adjustment module is further configured to: Split the power demand difference according to a preset adjustment stage to obtain sub-differences corresponding to each adjustment stage; Based on the historical power adjustment plan, determine the maximum power adjustment amplitude for each historical adjustment stage; For each adjustment stage, update the sub-difference within the adjustment stage based on the maximum power adjustment amplitude, and generate a power adjustment plan based on the updated results of each adjustment stage.

[0068] It should be noted that for other corresponding descriptions of each functional unit involved in the grid connection control system of a distributed power source provided in the embodiments of the present application, reference can be made to Figure 1 the corresponding descriptions in the method, which will not be elaborated here.

[0069] The embodiments of the present application further provide a computer device, specifically a personal computer, a server, a network device, etc. As Figure 3 shown, the computer device includes a bus, a processor, a memory, and a communication interface, and may further include an input / output interface and a display device. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store location information. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, the steps in the method embodiments are implemented.

[0070] Those skilled in the art can understand, Figure 3The structure shown is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0071] In one embodiment, a computer-readable storage medium is provided. The computer-readable storage medium may be non-volatile or volatile, and a computer program is stored thereon. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0072] In one embodiment, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0073] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0074] Those of ordinary skill in the art can understand that all or part of the processes in the above-described embodiment methods can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above various methods. Among them, any reference to a memory, database, or other medium used in the various embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the various embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the various embodiments provided in the present application can be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0075] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0076] The above-described embodiments only represent several implementation manners of the present application. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A grid-connected control method for distributed power sources, characterized in that, Including: After the distributed power source is connected to the grid, obtain real-time grid operation data, perform time series aggregation on the real-time grid operation data to generate a multi-dimensional grid state data set, and calculate a grid stability index according to a first data set in the multi-dimensional grid state data set, where the first data set includes the aggregated grid instantaneous voltage, grid frequency fluctuation, and grid load change rate; If the grid stability index is greater than a preset stability threshold, calculate the load difference between the actual grid load demand and the conventional grid load at the current moment and calculate the grid load demand change rate at the current moment according to a second data set in the multi-dimensional grid state data set, and calculate a grid output power target value according to the load difference, the grid load demand change rate, and the grid output power at the current moment, where the second data set includes the aggregated actual grid load demand and the grid output power; and determine whether there is a voltage transient dip at the distributed power source connection point, and when there is a voltage transient dip, calculate an output power compensation value of the distributed power source according to the voltage transient dip amplitude and the rated output power of the distributed power source; In the case where there is no voltage transient dip at the distributed power source connection point, adjust the grid output power based on the grid output power target value; In the case where there is a voltage transient dip at the distributed power source connection point, adjust the grid output power based on the grid output power target value, and adjust the output power of the distributed power source based on the output power compensation value of the distributed power source.

2. The method according to claim 1, characterized in that, The calculating the grid stability index according to the first data set in the multi-dimensional grid state data set includes: Align the aggregated grid instantaneous voltage, grid frequency fluctuation, and grid load change rate in the first data set according to the time dimension, and calculate the grid stability index according to the alignment result; Wherein, the grid stability index is calculated based on the following formula: ； S represents the power grid stability index, represents the weighted coefficient of the instantaneous voltage of the power grid, represents the aggregated instantaneous voltage of the power grid, represents the weighted coefficient of the frequency fluctuation of the power grid, represents the aggregated frequency fluctuation of the power grid, represents the weighted coefficient of the load change rate of the power grid, represents the aggregated load change rate of the power grid, Z represents the number of aggregation segments of the instantaneous voltage of the power grid, z represents the index of the data item of the aggregated instantaneous voltage of the power grid, m represents the number of aggregation segments of the frequency fluctuation of the power grid, j represents the index of the data item of the aggregated frequency fluctuation of the power grid, p represents the number of aggregation segments of the load change rate of the power grid, and k represents the index of the data item of the aggregated load change rate of the power grid.

3. The method according to claim 2, wherein The real-time grid operation data includes the maximum grid voltage, the minimum grid voltage, the grid frequency, the grid load, the actual grid load demand, and the grid output power; The performing time series aggregation on the real-time grid operation data to generate a multi-dimensional grid state data set includes: Based on the maximum grid voltage and the minimum grid voltage at the current sampling moment, calculate the average grid voltage, and use the average grid voltage as the grid instantaneous voltage at the current sampling moment; Calculate the difference between the grid frequency at the current sampling moment and the standard grid frequency, and use the absolute value of the difference as the grid frequency fluctuation at the current sampling moment; Calculate the load difference between the grid load at the current sampling moment and the grid load at the previous sampling moment, and calculate a first ratio between the load difference and the grid load at the previous sampling moment, and use the first ratio as the grid load change rate at the current sampling moment; Divide the grid instantaneous voltage, grid frequency fluctuation, grid load change rate, grid actual load demand, and grid output power corresponding to each sampling moment according to a preset time interval to obtain a grid instantaneous voltage set, a grid frequency fluctuation set, a grid load change rate set, a grid actual load demand set, and a grid output power set corresponding to each preset time interval; For each preset time interval, determine the maximum instantaneous voltage from the grid instantaneous voltage set, determine the maximum frequency fluctuation from the grid frequency fluctuation set, and determine the maximum load change rate from the grid load change rate set. Take the maximum instantaneous voltage, the maximum frequency fluctuation, and the maximum load change rate as the first aggregation result corresponding to the preset time interval, and arrange the first aggregation results corresponding to each preset time interval in chronological order to obtain a first data set; and, calculate the average values of the grid actual load demand set and the grid output power set respectively, take the grid actual load demand average value and the grid output power average value as the second aggregation result corresponding to the preset time interval, and arrange the second aggregation results corresponding to each preset time interval in chronological order to obtain a second data set.

4. The method according to claim 1, wherein Calculating the load difference between the grid actual load demand at the current moment and the grid normal load according to the second data set in the multi-dimensional grid state data set, and calculating the grid load demand change rate at the current moment. Calculating the grid output power target value according to the load difference, the grid load demand change rate, and the grid output power at the current moment includes: Calculating the load difference between the grid actual load demand at the current moment and the grid normal load according to the second data set in the multi-dimensional grid state data set; When the absolute value of the load difference is greater than a preset difference threshold, calculate the grid load demand change rate at the current moment based on the grid actual load demand at the current moment and the grid actual load demand at the previous moment, and calculate the product of the grid output power at the current moment and the grid load demand change rate. Take the difference between the grid output power at the current moment and the product result as the grid output power target value.

5. The method according to claim 1, wherein Calculating the output power compensation value of the distributed power source according to the voltage transient drop amplitude and the rated output power of the distributed power source includes: Calculating the voltage difference between the normal grid voltage and the grid voltage after the fall at the current moment, and calculating the second ratio of the voltage difference to the normal grid voltage. Take the second ratio as the voltage transient drop amplitude; Based on the voltage transient drop amplitude, determine the matching drop amplitude classification coefficient; Calculate the product of the rated output power of the distributed power source and the drop amplitude classification coefficient, and take the product result as the output power compensation value of the distributed power source.

6. The method according to claim 1, characterized in that, After adjusting the output power of the distributed power source, the method further includes: Real-time monitor the phase sequence characteristics of the connection point of the distributed power source, calculate the phase sequence difference between the phase sequence characteristics of the connection point of the distributed power source and the phase sequence characteristics of the power grid, and obtain phase sequence difference data; Calculate the harmonic impact evaluation value through the power grid harmonic interference level evaluation formula; According to the phase sequence difference data and the harmonic impact evaluation value, obtain the harmonic impact evaluation result, and when the harmonic impact evaluation result triggers the harmonic impedance adjustment condition, calculate the harmonic impedance adjustment value of the distributed power source through the harmonic impedance adjustment formula, and adjust the harmonic impedance of the distributed power source based on the harmonic impedance adjustment value.

7. The method according to claim 6, wherein The power grid harmonic interference level evaluation formula is as follows: Among them, THD represents the harmonic impact assessment value, represents the amplitude of the th harmonic component, represents the amplitude of the fundamental wave, represents the voltage amplitude of the distributed power source, represents the total harmonic distortion of the power grid, represents the total harmonic distortion of the distributed power source, represents the output current of the distributed power source, represents the maximum number of times of harmonic analysis, represents the number of times of the harmonic currently being analyzed; The harmonic impedance adjustment formula is as follows: ； Among them, represents the harmonic impedance adjustment value of the distributed power source.

8. The method according to claim 6 or 7, characterized in that, After adjusting the harmonic impedance of the distributed power source based on the harmonic impedance adjustment value, the method further includes: Based on the aggregated grid output power in the second data set, calculate the grid output power change rate corresponding to the current moment, and based on the aggregated grid actual load demand in the second data set, calculate the grid load demand change rate corresponding to the current moment; Calculate the change rate difference between the grid load demand change rate and the grid output power change rate corresponding to the current moment. If the change rate difference is greater than the power matching deviation threshold, obtain the output power of the distributed power source at the current moment and the grid predicted load demand, and calculate the power demand difference; Split the power demand difference according to a preset adjustment stage to obtain a power adjustment plan, and adjust the output power of the distributed power source according to the power adjustment plan.

9. The method according to claim 8, wherein The splitting of the power demand difference according to a preset adjustment stage to obtain a power adjustment plan includes: Split the power demand difference according to a preset adjustment stage to obtain the sub-difference corresponding to each adjustment stage; Based on the historical power adjustment plan, determine the maximum power adjustment amplitude of each historical adjustment stage; For each adjustment stage, update the sub-difference within the adjustment stage based on the maximum power adjustment amplitude, and generate a power adjustment plan based on the updated results of each adjustment stage.

10. A grid-connected control system for a distributed power source, characterized in that, Applied to the grid connection control method of the distributed power source according to any one of claims 1 to 9, the system includes: A real-time data acquisition module, configured to obtain real-time grid operation data after the distributed power source is connected to the grid, perform time series aggregation on the real-time grid operation data to generate a multi-dimensional grid state data set, and calculate a grid stability index according to the first data set in the multi-dimensional grid state data set, where the first data set includes the aggregated grid instantaneous voltage, grid frequency fluctuation, and grid load change rate; A calculation module, configured to, if the power grid stability index is greater than a preset stability threshold, calculate a load difference between the actual load demand of the power grid at the current moment and the conventional load of the power grid and calculate a change rate of the power grid load demand at the current moment according to a second data set in the multi-dimensional power grid state data set, and calculate a target value of the power grid output power according to the load difference, the change rate of the power grid load demand, and the power grid output power at the current moment, wherein the second data set includes the aggregated actual load demand of the power grid and the power grid output power; and determine whether there is a voltage transient dip at the distributed power source connection point, and when there is a voltage transient dip, calculate an output power compensation value of the distributed power source according to the voltage transient dip amplitude and the rated output power of the distributed power source; An adjustment module, configured to, in the case that there is no voltage transient dip at the distributed power source connection point, adjust the power grid output power based on the target value of the power grid output power; in the case that there is a voltage transient dip at the distributed power source connection point, adjust the power grid output power based on the target value of the power grid output power, and adjust the output power of the distributed power source based on the output power compensation value of the distributed power source.

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