Complementary substitution system and method for electricity, gas, cold and heat energy supply systems

Abstract

The invention relates to the technical field of power supply system compensation control, in particular to an electricity, gas, cold and heat energy supply system complementary substitution system and method. The method comprises the following steps: firstly, acquiring a power grid frequency, a starting moment and an ending moment of each frequency unstable time period, correspondingly compensated delay time of a conversion device and residual capacity of an energy storage device; further dividing the starting time to obtain a compensation effect coefficient and compensation delay time of each conversion device in the unstable time interval; and finally, comparing the fluctuation characteristic of the power grid frequency in the first half section of the current unstable time interval with the fluctuation characteristic of the power grid frequency in a preset historical neighborhood at the corresponding historical starting moment, and controlling a conversion device to pre-start to perform frequency compensation by combining the change of the residual capacity, the compensation effect coefficient and the compensation delay time. The pre-starting strategy of the conversion device is optimized, the timeliness and accuracy of frequency compensation are improved, the response delay influence is reduced, and the frequency compensation effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply system compensation control, and in particular to a system and method for complementary substitution of electricity, gas, cooling and heat energy supply systems. Background Art

[0002] An integrated energy system refers to the use of advanced physical information technology and innovative management models to integrate various energy sources such as coal, oil, natural gas, electricity, and thermal energy within a certain area, and achieve coordinated planning, optimized operation, collaborative management, and mutual complementarity among various heterogeneous energy subsystems.

[0003] In the multi-energy conversion of electricity, gas, cooling, and heat, inertia and time delay are two core dynamic characteristics that directly impact system stability, response speed, and the design of complementary control strategies. Inertia, representing the inertia of the physical process of energy storage or release, determines the lower limit of response speed. Delay, representing the difference between input commands and actual output, determines the effective energy replenishment time. These dynamic characteristics can significantly impact the system's power regulation capabilities, particularly when responding to rapid load fluctuations, easily leading to timing mismatches resulting in untimely or overcompensation. Summary of the Invention

[0004] In order to solve the technical problem that the existing multi-energy conversion control is affected by the time delay effect, resulting in unsatisfactory compensation effect, the purpose of the present invention is to provide a complementary replacement system and method for electricity, gas, cooling and heating energy supply systems. The technical solutions adopted are as follows: A method for complementary substitution of electricity, gas, cooling and heating energy supply systems, the method comprising: Obtain the grid frequency for each load, the start and end times of each frequency instability period, the corresponding compensation delay time of the conversion device, and the remaining capacity of the energy storage device; the loads include electricity, gas, cooling, and heating, and each load is used as the target load one by one; In the historical data of the target load, similar starting times on different days are grouped into the same unstable time interval; based on the relative length of each frequency unstable period and the corresponding delay time, a compensation effect coefficient of each conversion device in the unstable time interval is obtained; and based on the compensation effect coefficient and the length of the delay time, a compensation delay time of each conversion device of the target load in each unstable time interval is obtained; The fluctuation characteristics of the grid frequency in the first half of the current unstable time interval are compared with the fluctuation characteristics of the grid frequency in a preset neighborhood at the corresponding historical starting moment. Combined with the change in the remaining capacity, the compensation effect coefficient and the compensation delay time, the conversion device is controlled to pre-start and perform frequency compensation.

[0005] Furthermore, the method for obtaining the unstable time interval includes: The starting moments of all the frequency instability periods in the historical data are mapped to the time axis of the same day; starting from the first starting moment on the time axis, the starting moments within the neighborhood of the preset interval length of the first starting moment are divided into an unstable time interval; repeat starting from the remaining undivided first starting moment to obtain all the unstable time intervals; the time domain length of the unstable time interval is the preset interval length.

[0006] Furthermore, the method for obtaining the compensation effect coefficient includes: In any unstable time interval of the target load, the compensation effect coefficient of each conversion device on the target load in the corresponding unstable time interval is obtained based on the overall characteristics of the ratio of the length of the delay time when each conversion device performs compensation to the length of the corresponding frequency unstable time period; the overall characteristics of the ratio of the length of the delay time to the length of the corresponding frequency unstable time period are positively correlated with the compensation effect coefficient.

[0007] Furthermore, the method for obtaining the compensation delay time includes: For any unstable time interval of any of the conversion devices, when the compensation effect coefficient is greater than a preset effect threshold, the compensation delay time is set to 0; When the compensation effect coefficient is less than or equal to a preset effect threshold, the compensation delay time is obtained based on the difference between the compensation effect coefficient and the preset effect threshold, combined with the overall characteristics of the delay time corresponding to the conversion device in the unstable time interval; the difference between the compensation effect coefficient and the preset effect threshold, and the overall characteristics of the delay time are positively correlated with the compensation delay time.

[0008] Furthermore, the method of controlling the conversion device to pre-start and perform frequency compensation includes: The currently corresponding unstable time interval is used as the target interval; based on the range and variance of the grid frequency in the first half of the currently corresponding target interval, the currently corresponding instability coefficient is obtained; in the historical data of the target interval, the range and variance of the grid frequency in the preset historical neighborhood at each starting moment are integrated to obtain the instability reference coefficient of the target interval; based on the currently corresponding instability coefficient and the instability reference coefficient, it is determined whether to pre-start the conversion device for frequency compensation; When determining pre-start, a selection sequence of conversion devices is obtained based on the variation characteristics of the remaining capacity of the energy storage device corresponding to each conversion device, combined with the compensation effect coefficient corresponding to each conversion device; and a pre-start compensation sequence is obtained based on the compensation delay time of each conversion device for the entire target load in the historical data of the target interval, combined with the selection sequence; The available conversion device is selected from the selection sequence, and the corresponding conversion device is pre-started to perform frequency compensation on the target load in combination with the corresponding element value in the pre-start compensation sequence.

[0009] Furthermore, the method for determining whether to pre-start the conversion device for frequency compensation includes: When the unstable coefficient is greater than or equal to the unstable reference coefficient, it is determined that the pre-start conversion device performs frequency compensation.

[0010] Furthermore, the method for obtaining the selection sequence includes: Obtaining the remaining compensable time of each conversion device for the target load based on the overall change rate of the remaining capacity and the real-time remaining capacity of the energy storage device corresponding to each conversion device; fusing the remaining compensable time and the compensation effect coefficient to obtain a selected coefficient for each conversion device; the remaining compensable time and the compensation effect coefficient are both positively correlated with the selected coefficient; The conversion devices are sorted from large to small according to the selected coefficients to obtain a selection sequence of the conversion devices.

[0011] Furthermore, the method for obtaining the pre-start compensation sequence includes: The compensation delay times are sorted in the sorting order in the selection sequence to obtain a pre-start compensation sequence.

[0012] Furthermore, the length of the preset historical neighborhood is 30 minutes.

[0013] The present invention also proposes a complementary substitution system for electricity, gas, cold and heat energy supply systems, which includes a memory, a processor and a computer program stored in the memory and runnable on the processor. When the processor executes the computer program, it implements any one of the steps of the complementary substitution method for electricity, gas, cold and heat energy supply systems.

[0014] The present invention has the following beneficial effects: The present invention first obtains the grid frequency, the start and end times of each frequency instability period, the delay time of the conversion device, and the remaining capacity of the energy storage device to provide a basis for data analysis; further divides the similar start times in different days to facilitate analysis of the instability pattern of the grid frequency at different time stages of each day, and facilitates precise control of frequency compensation; further obtains the compensation effect coefficient of each conversion device in the unstable time interval, quantitatively represents the compensation effect of each conversion device on the target load in different unstable time intervals, and provides a basis for subsequent accurate frequency compensation; further obtains the compensation delay time of each conversion device in each unstable time interval of the target load, and provides a basis for subsequent pre-starting of the conversion device, so that the startup of the conversion device better matches the system requirements and improves the accuracy and adaptability of frequency compensation; finally, the fluctuation characteristics of the grid frequency in the first half of the current unstable time interval are compared with the fluctuation characteristics of the grid frequency in a preset historical neighborhood at the corresponding historical start time to predict the possibility of future frequency instability; based on the change in remaining capacity, the compensation effect coefficient and the compensation delay time, the most suitable conversion device is selected, and the conversion device is controlled to pre-start for frequency compensation. Based on the frequency fluctuation characteristics of the power grid and combined with historical data analysis, the present invention calculates the compensation effect coefficient, compensation delay time and pre-start advance amount, optimizes the pre-start strategy of the conversion device, improves the timeliness and accuracy of frequency compensation, reduces the impact of response delay, improves the frequency compensation effect, and better maintains power grid stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A flowchart of a method for complementary replacement of electricity, gas, cooling and heating energy supply systems provided by one embodiment of the present invention; Figure 2 A flowchart of a method for controlling pre-start of a conversion device to perform frequency compensation is provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0017] To further illustrate the technical means and effectiveness of the present invention in achieving its intended objectives, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail the specific implementation, structure, features, and effectiveness of a complementary and alternative system and method for electricity, gas, cooling, and heating energy supply systems proposed by the present invention. In the following description, references to different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0018] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0019] The following describes in detail a specific scheme of a complementary replacement system and method for electricity, gas, cold and heat energy supply systems provided by the present invention with reference to the accompanying drawings.

[0020] See also Figure 1 , which shows a flow chart of a complementary replacement method for electricity, gas, cooling and heating energy supply systems provided by one embodiment of the present invention, specifically including: Step S1: Obtain the grid frequency of each load, the start and end time of each frequency instability period, the corresponding compensation delay time of the conversion device, and the remaining capacity of the energy storage device; the loads include four types of loads: electricity, gas, cooling, and heating, and each load is used as the target load one by one.

[0021] In one embodiment of the present invention, the integrated energy management system is composed of four modules: load, energy storage device, and energy input and conversion device.

[0022] Energy input modules include wind power, photovoltaic power, natural gas, and the upstream power grid. Conversion modules include electric chillers, gas turbines, gas boilers, waste heat boilers, absorption chillers, and heat exchangers. Energy storage modules include batteries and thermal storage tanks. On the load side, there are four types of loads: electricity, gas, cooling, and heating.

[0023] The data collection frequency is set to 3 seconds per time, and the grid frequency of each load is collected. The frequency stability detection mechanism in the integrated energy management system determines the frequency instability, and records the start and end time of each frequency instability period; the delay time of the corresponding compensation conversion device is also recorded, and the remaining capacity of each energy storage device is collected to provide a basis for data analysis.

[0024] The frequency stability detection mechanism may be: setting a fixed threshold of 45-55 Hz, and when the collected grid frequency exceeds the fixed threshold, determining that frequency instability occurs.

[0025] First, select any one of the loads as the target load and analyze each load one by one.

[0026] It should be noted that since the analysis method for each load is the same, only the target load is used as an example and no further description is given. In other embodiments of the present invention, implementers can adjust the acquisition frequency and set other frequency stability detection mechanisms.

[0027] Step S2: In the historical data of the target load, similar starting times in different days are divided into the same unstable time interval; according to the relative length of each frequency instability period and the corresponding delay time, the compensation effect coefficient of each conversion device in the unstable time interval is obtained; based on the compensation effect coefficient and the length of the delay time, the compensation delay time of each conversion device of the target load in each unstable time interval is obtained.

[0028] Considering that most grid users use electricity on a daily basis, in the historical data of the target load, similar starting times on different days are divided into the same unstable time interval. This facilitates the analysis of the unstable pattern of the grid frequency at different time stages of each day, and is conducive to setting the most appropriate compensation method in different unstable time intervals and accurately controlling frequency compensation.

[0029] Preferably, in one embodiment of the present invention, the starting time of all frequency instability periods in the historical data is first mapped to the time axis of the same day to facilitate the division of time intervals. The time axis runs from 0:00 to 24:00, and each data point on the time axis corresponds to the starting time of a frequency instability period; Then, starting from the first starting moment on the time axis, the starting moments in the neighborhood of the preset interval length of the first starting moment are divided into an unstable time interval; Then, the method is repeated starting from the first starting moment of the remaining undivided space to obtain all unstable time intervals; the time domain length of the unstable time interval is the preset interval length.

[0030] As an example, the preset interval length is 30 minutes, and the starting times are sorted from left to right with the right as the positive direction of the time domain.

[0031] For example: the starting times are 180, 200, 220, 225, 230, and 300, in minutes. Before the first division, the first starting time is 180, and before the second division, the first undivided starting time is 220. Then the first unstable time interval is [180,210), including 180 and 200. The second unstable time interval is [220,250), including 200, 225, and 230. The third unstable time interval is [300,330), including 300.

[0032] In another embodiment of the present invention, the implementer may also directly divide the time from 0:00 to 24:00 every day into equal parts, such as 48 equal parts, and each time interval is used as an unstable time interval.

[0033] It should be noted that, in one embodiment of the present invention, historical data of the last seven days of the current day is obtained for analysis, and the range of historical data is limited, which can be adjusted by the implementer.

[0034] Taking into account that the relative length of the frequency instability period and the corresponding delay time reflects the delay characteristics and response capability of the conversion device, the compensation effect coefficient of each conversion device in the unstable time interval is obtained according to the relative length of each frequency instability period and the corresponding delay time, and the compensation effect of each conversion device on the target load in different unstable time intervals is quantitatively expressed, providing a basis for subsequent accurate frequency compensation.

[0035] Preferably, in one embodiment of the present invention, considering that the delay time refers to the time from when the compensation instruction is issued to when the compensation starts to take effect, the longer the delay time is relative to the frequency instability period, the longer the delay in communication, control, and execution before compensation. This means that after the conversion device starts frequency compensation for the target load, the time it takes to restore the frequency to a stable state is shorter, and the compensation effect is better. After the subsequent control pre-start eliminates the influence of the delay time, the normal frequency can be quickly restored. Based on this, within any unstable time interval of the target load, the compensation effect coefficient of each conversion device on the target load in the corresponding unstable time interval is obtained according to the overall characteristics of the ratio of the length of the delay time when each conversion device performs compensation to the length of the corresponding frequency unstable period.

[0036] Among them, the overall characteristic of the ratio of the length of the delay time to the length of the corresponding frequency instability period is positively correlated with the compensation effect coefficient.

[0037] As an example, the average of the ratios of the delay time of each conversion device during compensation to the length of the corresponding frequency instability period within any unstable time interval of the target load is used as the compensation effect coefficient of each conversion device on the target load in the corresponding unstable time interval.

[0038] By comparison, the relative length of the frequency instability period and the corresponding delay time is expressed; by using the mean value to represent the overall characteristics of the ratio, the compensation effect coefficient is obtained, which represents the frequency compensation effect of a conversion device on the target load within a period of unstable time.

[0039] As another example, the implementer may also obtain the mean, mode, and median of the ratio of the length of the delay time when each conversion device performs compensation to the length of the corresponding frequency instability period, perform weighted summation with weights of 0.5, 0.3, and 0.2 or other weights, express the overall characteristics of the ratio by weighted summation, and obtain the compensation effect coefficient.

[0040] Taking into account that the compensation effect coefficient represents the frequency compensation effect of a conversion device on the target load in an unstable time interval, and the length of the delay time represents the response speed of the conversion device, the compensation delay time of each conversion device of the target load in each unstable time interval is obtained based on the compensation effect coefficient and the length of the delay time, which provides a basis for the subsequent pre-start of the conversion device, makes the startup of the conversion device more in line with the system requirements, and improves the accuracy and adaptability of the frequency compensation.

[0041] Preferably, in one embodiment of the present invention, considering that a larger compensation effect coefficient of a conversion device indicates that the conversion device has a better compensation effect on the target load in the corresponding unstable time interval, and there is no need to compensate for the delay time, for any unstable time interval of any type of conversion device, when the compensation effect coefficient is greater than a preset effect threshold, the compensation delay time is set to 0; When the compensation effect coefficient of the conversion device is small, compensation is required. The smaller the compensation effect coefficient, the longer the delay time, indicating that the conversion device has a worse compensation effect on the target load in the corresponding unstable time interval. The longer the delay in starting compensation, the greater the amplitude of the delay time compensation needs to be. Based on this, when the compensation effect coefficient is less than or equal to the preset effect threshold, the compensation delay time is obtained according to the difference between the compensation effect coefficient and the preset effect threshold, combined with the overall characteristics of the delay time of the corresponding conversion device in the corresponding unstable time interval; the difference between the compensation effect coefficient and the preset effect threshold, and the overall characteristics of the delay time are positively correlated with the compensation delay time.

[0042] As an example, the compensation effect coefficient is linearly normalized, and the preset effect threshold is 0.5; When the compensation effect coefficient is less than or equal to the preset effect threshold, for any conversion device in any unstable time interval, the difference between the preset effect threshold and the compensation effect coefficient is normalized, and then multiplied by the mean of the delay time of the corresponding conversion device in the corresponding unstable time interval, and the product is used as the compensation delay time of the corresponding conversion device in the corresponding unstable time interval.

[0043] The mean of the delay time represents the overall characteristics of the delay time, and the difference between the preset effect threshold and the compensation effect coefficient represents the difference between the compensation effect coefficient and the preset effect threshold; normalization can adopt linear normalization.

[0044] In other embodiments of the present invention, the mean, mode, and median of the delay time may be obtained and fused in a weighted summation manner to represent the overall characteristics of the delay time, which will not be described in detail.

[0045] In another embodiment of the present invention, the length of the frequency instability period represents the time the system deviates from the stable state, which indirectly reflects the abnormal deviation degree of the target load. Therefore, the compensation delay time can also be obtained in combination with the length of the frequency instability period.

[0046] As an example, a longer period of frequency instability indicates more severe fluctuations during this time interval, and a greater compensation effort is required to adjust to a stable state. Therefore, a longer compensation delay may be required to ensure the compensation effect. Therefore, when the compensation effect coefficient is less than or equal to the preset effect threshold, for any conversion device in any unstable time interval, the difference between the preset effect threshold and the compensation effect coefficient is normalized by the product of the length of the frequency unstable period, and then multiplied by the mean of the delay time of the corresponding conversion device in the corresponding unstable time interval. The product is used as the compensation delay time of the corresponding conversion device in the corresponding unstable time interval.

[0047] Step S3: Compare the grid frequency fluctuation characteristics in the first half of the current unstable time interval with the grid frequency fluctuation characteristics in the preset historical neighborhood at the corresponding historical start time, and control the conversion device to pre-start and perform frequency compensation in combination with the change in remaining capacity, compensation effect coefficient and compensation delay time.

[0048] Considering that during the actual operation of the day, by the time the time reaches the halfway point of each unstable time interval, a large amount of grid frequency data is available for analysis. The grid frequency fluctuation characteristics in the first half of the current unstable time interval represent the grid frequency change trend and fluctuation intensity of the target load under the current system operation state. In the historical data corresponding to the current unstable time interval, the fluctuation characteristics of the grid frequency in the preset historical neighborhood at the historical starting time represent the typical evolution pattern of grid frequency instability. By comparing the two, the possibility of future frequency instability can be predicted. At the same time, the change in remaining capacity represents the energy supply of the energy storage device for frequency compensation; the compensation effect coefficient represents the compensation effect of different conversion devices on the target load during the current unstable time interval, providing a basis for selecting the conversion device; the compensation delay time represents the compensation for the delay time of the conversion device; Therefore, the change in remaining capacity, the compensation effect coefficient, and the compensation delay time are combined to control the pre-start of the conversion device for frequency compensation. By combining historical data with real-time data for intelligent prediction, the control conversion device responds in advance, reducing the impact of the time delay effect, optimizing the allocation of compensation resources, and improving system stability.

[0049] Preferably, in one embodiment of the present invention, see Figure 2 , which shows a flow chart of a method for controlling the pre-start of a conversion device to perform frequency compensation provided by an embodiment of the present invention, specifically comprising: Step S301: The currently corresponding unstable time interval is used as the target interval; the currently corresponding instability coefficient is obtained based on the range and variance of the grid frequency in the first half of the currently corresponding target interval; in the historical data of the target interval, the range and variance of the grid frequency in the preset historical neighborhood at each starting moment are integrated to obtain the instability reference coefficient of the target interval; based on the currently corresponding instability coefficient and the instability reference coefficient, it is determined whether to pre-start the conversion device for frequency compensation.

[0050] First, the current corresponding unstable time interval is used as the target interval to facilitate subsequent description.

[0051] Considering that when the grid frequency fluctuates violently, it corresponds to grid frequency instability. The range of the grid frequency represents the fluctuation range of the grid frequency. The larger the fluctuation range, the more violent the fluctuation and the greater the degree of instability. The larger the variance of the grid frequency, the greater the dispersion of the grid frequency, the more violent the fluctuation and the greater the degree of instability. Therefore, the instability characteristics of the grid frequency are quantified by the range and variance of the grid frequency, and then according to the current corresponding instability coefficient and instability reference coefficient, it is analyzed whether the current grid frequency will evolve into frequency instability, so as to determine whether to pre-start the conversion device for frequency compensation.

[0052] As an example, the product of the range and variance of the power grid frequency in the first half of the current target interval is used as the current corresponding instability coefficient; the range and variance are integrated by multiplication, and the instability coefficient is used to represent the fluctuation characteristics of the power grid frequency in the first half of the current unstable time interval; The preset time domain length of the historical neighborhood is 30 minutes. In the historical data of the target interval, the product of the range and variance of the power grid frequency within 30 minutes before each starting moment is used as the unstable reference sub-coefficient of each starting moment. The average value of the unstable reference sub-coefficients of all starting moments in the target interval is used as the unstable reference coefficient of the target interval.

[0053] When the unstable coefficient is greater than or equal to the unstable reference coefficient, it is determined that the pre-start conversion device performs frequency compensation.

[0054] As another example, after the range and variance of the grid frequency are linearly normalized respectively, they are fused by addition or weighted summation to obtain the instability coefficient and the instability reference sub-coefficient.

[0055] It should be noted that in other embodiments of the present invention, the implementer may also obtain the mean, mode and median of the unstable reference sub-coefficients, and obtain the unstable reference coefficient by weighted summation; and set preset historical neighborhoods of other lengths.

[0056] Step S302: When determining pre-start, a selection sequence for the conversion devices is obtained based on the variation characteristics of the remaining capacity of the energy storage device corresponding to each conversion device, combined with the compensation effect coefficient corresponding to each conversion device. In the historical data of the target interval, a pre-start compensation sequence is obtained based on the compensation delay time of each conversion device for the overall target load, combined with the selection sequence.

[0057] When pre-start is determined, it is necessary to determine the pre-start switching device and the amount of advance time for pre-start.

[0058] Taking into account the changing characteristics of the remaining capacity of the energy storage device corresponding to each conversion device, it represents the remaining time of the energy storage device in the current available conversion device for frequency compensation. The compensation effect coefficient represents the compensation effect of the conversion device on the target load in the current unstable time interval. Therefore, the selection sequence is obtained and the selection priority of different conversion devices is determined, which facilitates the selection of the most suitable conversion device for frequency compensation.

[0059] In one embodiment of the present invention, first, the remaining compensable time of each conversion device for the target load is obtained based on the overall change rate of the remaining capacity and the real-time remaining capacity of the energy storage device corresponding to each conversion device.

[0060] As an example, in the historical data of the current target interval, the average of the slopes of the changes in the remaining capacity of the corresponding energy storage device when any conversion device performs frequency compensation for the target load is obtained, and the absolute value is taken as the energy consumption rate, which represents the overall rate of change of the remaining capacity; the ratio of the real-time remaining capacity to the energy consumption rate is normalized and used as the remaining compensation time of the corresponding conversion device for the target load at the current time.

[0061] As another example, obtain the remaining capacity change curve of the energy storage device corresponding to each conversion device on the current day, obtain the average of the slopes of the curve segments that consume energy in the remaining capacity change curve, take the absolute value as the energy consumption rate, and thus obtain the remaining compensable time; simplify the analysis process, and sacrifice some accuracy to increase the calculation speed.

[0062] It should be noted that normalization can use linear normalization or existing normalization functions such as the sigmoid function; when the mean value of the slope of the change in the remaining capacity of the energy storage device is greater than 0, it means that the energy consumption rate of the frequency compensation of the corresponding energy storage device is less than the charging rate, and the remaining compensable time is directly set to 1.

[0063] Then the remaining compensable time and the compensation effect coefficient are integrated to obtain the selected coefficient of each conversion device.

[0064] Since the longer the remaining compensable time is, the larger the compensation effect coefficient is, which means that the energy reserve of the corresponding conversion device is more sufficient, the compensation effect is better, and the more likely it is to be selected for frequency compensation, so the remaining compensable time and the compensation effect coefficient are positively correlated with the selection coefficient.

[0065] As an example, the product of the remaining compensable time and the compensation effect coefficient is used as the selected coefficient of the corresponding conversion device in the current unstable time interval.

[0066] Finally, the conversion devices are sorted from large to small according to the selected coefficients to obtain a selection sequence of the conversion devices; the smaller the sequence number of the conversion device in the selection sequence, the higher the selection priority.

[0067] The selection sequence determines the compensation priority of the conversion device. To facilitate the adjustment of the start-up time of each conversion device and achieve accurate pre-start, the pre-start compensation sequence is obtained based on the compensation delay time of each conversion device for the overall target load in the historical data of the target interval and combined with the selection sequence.

[0068] As an example, the compensation delay times are sorted in the sort order in the selection sequence to obtain a pre-start compensation sequence.

[0069] Step S303: selecting the first available conversion device from the selection sequence, and pre-starting the corresponding conversion device to perform frequency compensation on the target load in combination with the corresponding element value in the pre-start compensation sequence.

[0070] Taking into account that the conversion device may fail or be in an occupied state, and the smaller the conversion device number in the selection sequence, the higher the selection priority, the first available conversion device is selected from the selection sequence, and the corresponding element value in the pre-start compensation sequence is used as the pre-start advance time. The corresponding conversion device is pre-started to perform frequency compensation on the target load.

[0071] It should be noted that when frequency compensation is performed on the target load, it is necessary to utilize the conversion device whose energy source is other loads for compensation, and only the conversion device whose other loads are energy sources is considered.

[0072] It should be noted that the method of performing frequency compensation on a certain load by using a conversion device is a technical means well known to those skilled in the art and will not be described in detail here.

[0073] An embodiment of the present invention also provides a complementary substitution system for electricity, gas, cold and heat energy supply systems, which includes a memory, a processor and a computer program, wherein the memory is used to store the corresponding computer program, and the processor is used to run the corresponding computer program. When the computer program runs in the processor, it can implement a complementary substitution method for electricity, gas, cold and heat energy supply systems described in steps S1-S3.

[0074] In summary, in order to address the technical problem that the existing multi-energy conversion control is affected by the time delay effect, resulting in unsatisfactory compensation effect, the present invention first obtains the grid frequency of each load, the start and end times of each frequency instability period, the delay time of the corresponding compensated conversion device, and the remaining capacity of the energy storage device; further, in the historical data of the target load, the similar start times in different days are divided into the same unstable time interval; further, according to the relative length of each frequency instability period and the corresponding delay time, the compensation effect coefficient of each conversion device in the unstable time interval is obtained; further, based on the compensation effect coefficient and the length of the delay time, the compensation delay time of each conversion device of the target load in each unstable time interval is obtained; finally, the fluctuation characteristics of the grid frequency in the first half of the current unstable time interval are compared with the fluctuation characteristics of the grid frequency in the preset historical neighborhood of the corresponding historical start time, and the conversion device is controlled to pre-start for frequency compensation in combination with the change in residual capacity, the compensation effect coefficient and the compensation delay time.

[0075] Based on the frequency fluctuation characteristics of the power grid and combined with historical data analysis, the present invention calculates the compensation effect coefficient, compensation delay time and pre-start advance amount, optimizes the pre-start strategy of the conversion device, improves the timeliness and accuracy of frequency compensation, reduces the impact of response delay, improves the frequency compensation effect, and better maintains power grid stability.

[0076] It should be noted that the order in which the embodiments of the present invention are described above is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0077] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A complementary replacement method for electricity, gas, cooling and heating energy supply systems, characterized in that: The method comprises: Obtain the grid frequency for each load, the start and end times of each frequency instability period, the corresponding compensation delay time of the conversion device, and the remaining capacity of the energy storage device; the loads include electricity, gas, cooling, and heating, and each load is used as the target load one by one; In the historical data of the target load, similar starting times on different days are grouped into the same unstable time interval; based on the relative length of each frequency unstable period and the corresponding delay time, a compensation effect coefficient of each conversion device in the unstable time interval is obtained; and based on the compensation effect coefficient and the length of the delay time, a compensation delay time of each conversion device of the target load in each unstable time interval is obtained; The fluctuation characteristics of the grid frequency in the first half of the current unstable time interval are compared with the fluctuation characteristics of the grid frequency in a preset historical neighborhood at the corresponding historical start moment. Combined with the change in the remaining capacity, the compensation effect coefficient and the compensation delay time, the conversion device is controlled to pre-start for frequency compensation.

2. A complementary replacement method for electricity, gas, cooling and heating energy supply systems according to claim 1, characterized in that: The method for obtaining the unstable time interval includes: The starting moments of all the frequency instability periods in the historical data are mapped to the time axis of the same day; starting from the first starting moment on the time axis, the starting moments within the neighborhood of the preset interval length of the first starting moment are divided into an unstable time interval; repeat starting from the remaining undivided first starting moment to obtain all the unstable time intervals; the time domain length of the unstable time interval is the preset interval length.

3. The complementary replacement method of electricity, gas, cooling and heating energy supply systems according to claim 1, characterized in that: The method for obtaining the compensation effect coefficient includes: In any unstable time interval of the target load, the compensation effect coefficient of each conversion device on the target load in the corresponding unstable time interval is obtained based on the overall characteristics of the ratio of the length of the delay time when each conversion device performs compensation to the length of the corresponding frequency unstable time period; the overall characteristics of the ratio of the length of the delay time to the length of the corresponding frequency unstable time period are positively correlated with the compensation effect coefficient.

4. The complementary replacement method of electricity, gas, cooling and heating energy supply systems according to claim 1, characterized in that: The method for obtaining the compensation delay time includes: For any unstable time interval of any of the conversion devices, when the compensation effect coefficient is greater than a preset effect threshold, the compensation delay time is set to 0; When the compensation effect coefficient is less than or equal to a preset effect threshold, the compensation delay time is obtained based on the difference between the compensation effect coefficient and the preset effect threshold, combined with the overall characteristics of the delay time corresponding to the conversion device in the unstable time interval; the difference between the compensation effect coefficient and the preset effect threshold, and the overall characteristics of the delay time are positively correlated with the compensation delay time.

5. The complementary replacement method of electricity, gas, cooling and heating energy supply systems according to claim 1, characterized in that: The method of controlling the conversion device to pre-start and perform frequency compensation includes: The currently corresponding unstable time interval is used as the target interval; based on the range and variance of the grid frequency in the first half of the currently corresponding target interval, the currently corresponding instability coefficient is obtained; in the historical data of the target interval, the range and variance of the grid frequency in the preset historical neighborhood at each starting moment are integrated to obtain the instability reference coefficient of the target interval; based on the currently corresponding instability coefficient and the instability reference coefficient, it is determined whether to pre-start the conversion device for frequency compensation; When determining pre-start, a selection sequence of conversion devices is obtained based on the variation characteristics of the remaining capacity of the energy storage device corresponding to each conversion device, combined with the compensation effect coefficient corresponding to each conversion device; and a pre-start compensation sequence is obtained based on the compensation delay time of each conversion device for the entire target load in the historical data of the target interval, combined with the selection sequence; The first available conversion device is selected from the selection sequence, and the corresponding conversion device is pre-started to perform frequency compensation on the target load in combination with the corresponding element value in the pre-start compensation sequence; the smaller the sequence number of the conversion device in the selection sequence, the higher the selection priority.

6. A complementary replacement method for electricity, gas, cooling and heating energy supply systems according to claim 5, characterized in that: The method for determining whether to pre-start the conversion device for frequency compensation includes: When the unstable coefficient is greater than or equal to the unstable reference coefficient, it is determined that the pre-start conversion device performs frequency compensation.

7. The complementary replacement method of electricity, gas, cooling and heating energy supply systems according to claim 5, characterized in that: The method for obtaining the selection sequence includes: Obtaining the remaining compensable time of each conversion device for the target load based on the overall change rate of the remaining capacity and the real-time remaining capacity of the energy storage device corresponding to each conversion device; fusing the remaining compensable time and the compensation effect coefficient to obtain a selected coefficient for each conversion device; the remaining compensable time and the compensation effect coefficient are both positively correlated with the selected coefficient; The conversion devices are sorted from large to small according to the selected coefficients to obtain a selection sequence of the conversion devices.

8. The complementary replacement method of electricity, gas, cooling and heating energy supply systems according to claim 5, characterized in that: The method for obtaining the pre-start compensation sequence includes: The compensation delay times are sorted in the sorting order in the selection sequence to obtain a pre-start compensation sequence.

9. The complementary replacement method of electricity, gas, cooling and heating energy supply systems according to claim 1, characterized in that: The length of the preset historical neighborhood is 30 minutes.

10. A complementary replacement system for electricity, gas, cooling and heating energy supply systems, the system comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for complementary substitution of electricity, gas, cold and heat energy supply systems as described in any one of claims 1 to 9 are implemented.

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