Method and equipment for actively supporting inertia of power grid by expansion generator set, and medium

Abstract

The invention discloses a method, system, equipment and medium for an expansion generator set to actively support the inertia of a power grid, and belongs to the technical field of compressed air energy storage, and the method comprises the steps: collecting voltage and current signals of the power grid in real time, calculating the frequency value of the power grid from the collected signals, and obtaining the frequency data of the power grid; performing differential calculation on the obtained frequency data to obtain a frequency difference and a frequency change rate; calculating upper and lower limits of power grid rotational inertia and system adjustable rotational inertia resources in real time according to unit operation conditions in a regional power grid; according to the frequency difference and the frequency change rate, system rotational inertia margins under the maximum frequency difference condition and the maximum frequency change rate condition are calculated; and controlling the compressed air energy storage unit to perform active adjustment based on a calculation result. Inertia support is realized, the frequency fluctuation of the power grid can be quickly responded, the frequency stability of the regional power grid is enhanced, the acceptance capability of the regional power grid to renewable energy sources is improved, and safe and reliable operation of the power grid is ensured.

Description

Technical Field

[0001] This invention relates to the field of compressed air energy storage technology, specifically to a method, device, and medium for an expander generator set to actively support the inertia of the power grid. Background Technology

[0002] In recent years, the application of renewable energy sources such as wind and solar power in power systems has increased rapidly. While these energy sources are connected to the grid via power electronic converters, achieving efficient utilization of clean energy, they lack the mechanical rotational inertia of traditional synchronous generators. Meanwhile, compressed air energy storage (CAES) systems, as a large-scale energy storage technology, possess advantages such as large storage capacity, long storage period, and low environmental pollution, and are considered one of the most promising large-scale energy storage technologies. In traditional CAES systems, during the compression phase, the compressor is driven by an electric motor, consuming grid power; during the release phase, high-pressure air drives an expander to power a generator. However, current CAES systems have not yet fully realized their potential in grid frequency regulation.

[0003] Due to the large-scale integration of new energy power sources, the inertia level of the regional power grid has decreased, resulting in weakened system stability when subjected to disturbances and increased risk of grid frequency fluctuations. Secondly, the frequency regulation response of traditional thermal power units is lagging, and the units are in peak-shaving operation for a long time, making it difficult to meet the grid's demand for rapid frequency support. In addition, the research focus of conventional CAES expander generators is mainly on power output control and frequency regulation, while the development of the inertia potential of its rotating parts is still in its initial stage.

[0004] To improve the stability of regional power grids, a technical solution is needed to develop that can provide adjustable rotational inertia support to the power grid when its inertia changes, utilizing a CAES system. This technology can solve the problems in existing technologies where regional power grids suffer from reduced inertia and poor frequency stability due to the integration of renewable energy, and the slow response of thermal power units prevents effective inertia support.

[0005] Therefore, there is an urgent need for a technical solution that can provide adjustable rotational inertia support for the power grid when the grid inertia changes using a CAES system. Summary of the Invention

[0006] In view of the above-mentioned problems, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to solve the problems in existing technologies where regional power grids suffer from reduced inertia and poor frequency stability due to the integration of renewable energy, and where thermal power units respond slowly and cannot effectively support inertia. This invention proposes that, under the dual constraints of frequency deviation and frequency change rate, when fluctuations occur in new energy sources such as wind and solar power, the rapid start-up and regulation characteristics of compressed air energy storage are used to adjust the operating state of the expander generator, ensuring that the rotational inertia of the expanded generator after the operating state adjustment meets the required specifications.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for an expansion generator set to actively support the inertia of the power grid, comprising, Install a power grid monitoring unit to collect voltage and current signals from the power grid in real time, calculate the power grid frequency value from the collected signals, and obtain power grid frequency data; perform differential calculations on the acquired frequency data to obtain the frequency difference and frequency change rate; calculate the upper and lower limits of the power grid's moment of inertia and the system's adjustable moment of inertia resources in real time based on the operating status of the units within the regional power grid; calculate the system's moment of inertia margin under the conditions of maximum frequency difference and maximum frequency change rate based on the frequency difference and frequency change rate; and control the compressed air energy storage unit to perform active power regulation based on the calculation results.

[0009] As a preferred embodiment of the method for actively supporting the inertia of the power grid by an expansion generator set as described in this invention, the calculation of the frequency value of the power grid includes: installing a high-precision power grid monitoring unit at the power grid interface, connecting to the power grid through voltage transformers and current transformers, and collecting the voltage and current signals of the power grid in real time. The frequency value of the power grid is calculated from the acquired signal using the Fourier transform algorithm.

[0010] As a preferred embodiment of the method for actively supporting the grid inertia of an expansion generator set according to the present invention, the differential calculation includes: after the grid frequency acquisition module obtains the grid frequency value, the frequency signal is sent to the frequency difference and frequency change rate calculation module to calculate the frequency difference. and frequency change rate The relationship between frequency difference and rate of change of frequency is: in, It is a function of the rate of change of frequency over time.

[0011] As a preferred embodiment of the method for actively supporting the grid inertia of an expandable generator set according to the present invention, wherein: the upper and lower limits of the real-time calculation of the grid rotational inertia and the system adjustable rotational inertia resources include the real-time calculation of the system rotational inertia, and the calculation formula of the rotational inertia is: in, Let i be the rated power of the i-th thermal power unit. Let be the inertial time constant of the i-th thermal power unit. Let be the start-stop coefficient of the i-th thermal power unit, which is 1 when starting and 0 when stopping; The rated power of the j-th new energy unit is Let be the inertial time constant of the j-th new energy unit. Let be the start-stop coefficient of the j-th new energy unit, which is 1 when starting and 0 when stopping; This is the rated power of the Lth CAES expander unit. Let L be the inertial time constant of the Lth CAES expander unit. is the start-up / shutdown coefficient of the Lth CAES expander unit, which is 1 when starting and 0 when stopping; n is the number of thermal power units, m is the number of new energy units, s is the number of CAES expander units in the regional power grid, and i, j, and L are variable indices. The upper and lower limits of the adjustable inertia resources of the regional power grid system are calculated. The upper limit is equal to the rotational inertia of the system when all units in the grid are running; the lower limit is equal to the rotational inertia of the system after all compressed air units are shut down.

[0012] As a preferred embodiment of the method for actively supporting the grid inertia of an expansion generator set according to the present invention, wherein: the system rotational inertia margin for calculating the maximum frequency difference and the maximum frequency change rate includes, in At time 1, no frequency difference occurs. At this time, an active power disturbance occurs in the system, and the rate of frequency change is at its maximum. The system inertia that the system can withstand independently at the maximum rate of frequency change is... for: in, For system active power disturbance, for The rate of change of frequency at any given time is the maximum rate of change of frequency of the system. exist At time t, the frequency difference is at its maximum, and the rate of frequency change is 0. Then, the system inertia that can withstand the maximum frequency difference alone is... for: in, The system inertia is required to meet the maximum frequency difference that the system can withstand. This is the droop coefficient of the primary frequency modulation of the system. The system damping coefficient is... These are the mechanical characteristics of thermal power units / compressed air energy storage units and their comprehensive influence on the system frequency response. The time constant of the dynamic response of the generator frequency regulator of the synchronous unit within the system. The damping ratio is the frequency response process of the system that varies with time. It refers to the natural frequency in the dynamic frequency response process.

[0013] As a preferred embodiment of the method for actively supporting the grid inertia of an expansion generator set according to the present invention, the calculation of the system rotational inertia margin under the conditions of maximum frequency difference and maximum frequency change rate further includes defining the system required inertia. for: exist This is the moment when the active disturbance occurs, at which point the rate of frequency change is at its maximum. Calculate the system inertia margin for the cases where the frequency difference reaches its maximum and the frequency change rate is at its maximum. : when When the value is ≥0, it indicates that the system margin is sufficient to meet the system inertia requirements. The thermal power unit adjusts its output according to the active power deviation, outputting or reducing active power to the system, and adjusting the frequency difference to stabilize the system. when A value less than 0 indicates insufficient system margin; the existing inertia does not meet the real-time inertia requirements of the system. In this case, the compressed air energy storage unit is started. When the system inertia margin... After the value reaches ≥0, the compressed air energy storage unit will then adjust the active power to eliminate active power disturbances.

[0014] As a preferred embodiment of the method for actively supporting the grid inertia of an expansion generator set according to the present invention, the calculation of the system rotational inertia margin under the conditions of maximum frequency difference and maximum frequency change rate further includes defining the system inertia sufficiency. for: The range of system inertia margin is selected as 0 < ≤1%; when Under the condition of <0, the system starts the compressed air energy storage unit to make the real-time inertia meet the system's required inertia. At this time, the compressed air energy storage unit prioritizes frequency adjustment to adjust the frequency difference. Based on the number of compressed air energy storage units currently operating within the regional power grid, the corresponding active power regulation weighting ratio is determined according to the current rated installed capacity. The weighting is calculated as follows: in, The active power regulation weight of the Lth CAES unit. Let L be the rated power of the Lth CAES unit, and x be the number of CAES units started in the system due to the adjustment of rotational inertia, where 1 ≤ x. <s。

[0015] As a preferred embodiment of the method for actively supporting the grid inertia of an expandable generator set according to the present invention, wherein: the control of the compressed air energy storage unit for active power regulation includes active power regulation of the compressed air energy storage unit. for: when When ≥0, the sufficiency is judged to be 0< Is the ≤1% condition met? If sufficiency is 0 < If the condition of ≤1% is not met, CAES units are sorted by active power regulation weight coefficient from smallest to largest and then disconnected in order until the adequacy ratio is 0 < The condition of ≤1% is met.

[0016] The present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, characterized in that the processor executes the computer program to implement the steps of the method for actively supporting the inertia of an expansion generator set.

[0017] The present invention provides a computer-readable storage medium having a computer program stored thereon, characterized in that, when the computer program is executed by a processor, it implements the steps of the method for actively supporting the inertia of an expansion generator set.

[0018] The beneficial effects of this invention are as follows: By implementing this invention, considering frequency changes and frequency change rate constraints, inertia support is achieved, enabling rapid response to grid frequency fluctuations and enhancing the frequency stability of regional power grids; by fully utilizing the regulation capability of the compressed air energy storage system's expansion generator, the regional power grid's ability to accept renewable energy is improved, ensuring the safe and reliable operation of the power grid. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a general flowchart of a method for actively supporting the inertia of a power grid using an expandable generator set, as provided in one embodiment of the present invention. Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0022] Example 1, referring to Figure 1 This is one embodiment of the present invention, which provides a method for actively supporting the grid inertia of an expandable generator set, comprising: S100. Install a power grid monitoring unit to collect voltage and current signals of the power grid in real time, calculate the frequency value of the power grid from the collected signals, and obtain power grid frequency data. S200. By performing differential calculations on the acquired frequency data, the frequency difference and frequency change rate are obtained. S300: Calculate the upper and lower limits of the grid rotational inertia and the system's adjustable rotational inertia resources in real time based on the operating status of the generating units within the regional power grid. S400. Calculate the system moment of inertia margin under the conditions of maximum frequency difference and maximum frequency change rate based on the frequency difference and the frequency change rate. S500 controls the active power regulation of the compressed air energy storage unit based on calculation results.

[0023] Therefore, in response to the existing problems, a method for actively supporting the inertia of a power grid system using compressed air energy storage is provided through steps S100-S500. This method is applicable to regional power grids containing wind and solar turbines and multiple CAES units, and provides inertia support under the dual constraints of frequency change rate and frequency deviation.

[0024] Example 2, refer to Figure 1 This is one embodiment of the present invention, which provides a method for actively supporting the grid inertia of an expandable generator set, comprising: In this invention, the compressed air energy storage unit specifically refers to the expansion generator unit in its energy release phase.

[0025] S100. Install a power grid monitoring unit to collect voltage and current signals of the power grid in real time, calculate the frequency value of the power grid from the collected signals, and obtain power grid frequency data. The acquisition of power grid frequency and frequency change rate is first achieved by installing a high-precision power grid monitoring unit, such as a smart meter or power grid quality analyzer, at the power grid interface. This unit is connected to the power grid via voltage transformers (PT) and current transformers (CT) to collect the voltage and current signals of the power grid in real time.

[0026] The frequency value of the power grid is calculated from the collected signals using algorithms such as Fourier transform.

[0027] S200. By performing differential calculations on the acquired frequency data, the frequency difference and frequency change rate are obtained. After acquiring the power grid frequency value, the power grid frequency acquisition module sends the frequency signal to the frequency difference and frequency change rate calculation module to calculate the frequency difference. and frequency change rate The frequency difference is the difference between the measured frequency and the rated frequency. The frequency change rate df / dt is obtained by differentiating the frequency signal with respect to time. The relationship between the frequency difference and the frequency change rate is: in, It is a function of the rate of change of frequency over time.

[0028] S300. Based on the operating conditions of the generating units within the regional power grid, calculate the upper and lower limits of the power grid's moment of inertia and the system's adjustable moment of inertia resources. The moment of inertia of the system is calculated in real time, and the formula for calculating the moment of inertia is: in, Let i be the rated power of the i-th thermal power unit. Let be the inertial time constant of the i-th thermal power unit. Let be the start-stop coefficient of the i-th thermal power unit, which is 1 when starting and 0 when stopping; The rated power of the j-th new energy unit is Let be the inertial time constant of the j-th new energy unit. Let be the start-stop coefficient of the j-th new energy unit, which is 1 when starting and 0 when stopping; This is the rated power of the Lth CAES expander unit. Let L be the inertial time constant of the Lth CAES expander unit. Let be the start-up / shutdown coefficient of the Lth CAES expander unit, which is 1 when starting and 0 when stopping; n is the number of thermal power units, m is the number of new energy units, s is the number of CAES expander units in the regional power grid, and i, j, and L are variable indices; it should be noted that for the CAES expander unit, the inertial time constant is obtained by decoupling the rotational speed of its rotating parts (expander-generator) from the grid frequency through a power electronic converter (such as a frequency converter) connected to the grid. By using a virtual synchronous generator or a similar virtual inertia control strategy, the converter output characteristics of the CAES unit simulate the rotor motion equation of the synchronous generator, and the optimal value obtained is the inertial time constant.

[0029] Calculate the upper and lower limits of adjustable inertia resources for the regional power grid system. The upper limit is equal to the rotational inertia of the system when all units (thermal power, renewable energy, CAES) are running. Assuming there are n thermal power units, m renewable energy units, and s compressed air energy storage units, then: The lower limit is equal to the system's moment of inertia after all compressed air units (i.e., new energy units and CAES units) have been shut down: in, This is the upper limit of resources. This is the lower limit for resources.

[0030] S400. Calculate the system moment of inertia margin under the conditions of maximum frequency difference and maximum frequency change rate based on the frequency difference and the frequency change rate. Calculate the system inertia margin under the conditions of maximum frequency change rate and maximum frequency difference. Based on the frequency difference and frequency change rate, and combined with the preset maximum allowable frequency difference and maximum allowable frequency change rate, calculate the minimum rotational inertia (i.e., the required inertia) required by the system to meet the frequency difference constraint and the frequency change rate constraint, respectively. Compare the current rotational inertia calculated by the system in real time with the required inertia to obtain the system rotational inertia margin. Specifically, in At time 1, no frequency difference occurs. At this time, an active power disturbance occurs in the system, and the rate of frequency change is at its maximum. The system inertia that the system can withstand independently at the maximum rate of frequency change is... for: in, For system active power disturbance, for The rate of change of frequency at any given time is the maximum rate of change of frequency of the system. exist At time t, the frequency difference is at its maximum, and the rate of frequency change is 0. Then, the system inertia that can withstand the maximum frequency difference alone is... for: in, The system inertia is required to meet the maximum frequency difference that the system can withstand. This is the droop coefficient of the primary frequency modulation of the system. The system damping coefficient is... These are the mechanical characteristics of thermal power units / compressed air energy storage units and their comprehensive influence on the system frequency response. The time constant of the dynamic response of the generator frequency regulator of the synchronous unit within the system. is the damping ratio of the system's frequency response process over time, is the natural frequency in the dynamic frequency response process.

[0031] Define the system demand inertia as: At is the moment when the active power disturbance appears, and at this time the frequency change rate is the largest; is the moment when the frequency difference reaches the maximum. Calculate the system inertia margin in the case of the largest frequency change rate and the largest frequency difference : When ≥0, it indicates that the system margin is sufficient and meets the system inertia demand. The thermal power unit adjusts its output according to the active power deviation, outputs or reduces active power to the system, and adjusts the frequency difference to stabilize the system; When <0, it indicates that the system margin is insufficient and the existing inertia does not meet the real-time system inertia demand. At this time, start the compressed air energy storage unit. When the system inertia margin ≥0, the compressed air energy storage unit performs active power adjustment again to eliminate the active power disturbance.

[0032] Define the system inertia abundance as: It should be noted that in order to ensure the stable operation of the system, prevent the system rotational inertia from being too large under positive frequency difference conditions, or keep the rotational inertia within a suitable range during normal system operation, the range of the system inertia abundance is selected as 0 < ≤1%.

[0033] When <0, the compressed air energy storage unit is started in the system. After the real-time inertia meets the system demand inertia, at this time, the compressed air energy storage unit preferentially adjusts the frequency difference for frequency modulation.

[0034] According to the number of compressed air energy storage units operating in the regional power grid, determine the weighted proportion of its active power regulation according to its rated installed capacity. The weight calculation is as follows: Among them, is the active power regulation weight of the Lth CAES unit, is the rated power of the Lth CAES unit, x is the number of CAES units started in the system due to adjusting the rotational inertia, 1 ≤ x < s, and s is the total number of CAES units in the regional power grid.

[0035] S500 controls the active power regulation of the compressed air energy storage unit based on calculation results.

[0036] Compressed air energy storage unit active power regulation for: when When ≥0, the sufficiency is judged to be 0< Is the ≤1% condition met? If sufficiency is 0 < If the condition of ≤1% is not met, CAES units are sorted by active power regulation weight coefficient from smallest to largest and then disconnected in order until the adequacy ratio is 0 < The condition of ≤1% is met.

[0037] Example 3 is an embodiment of the present invention, which provides a method for an expansion generator set to actively support the inertia of the power grid. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through experiments.

[0038] Simulation Experiment 1: The power grid consists of thermal power units, new energy wind and solar power units, and compressed air energy storage. At this time, wind and solar resources are abundant, and the power grid achieves both power balance and electrical balance. Thermal power units and new energy wind and solar power units operate within the system without active power disturbances, frequency differences, or frequency changes. The system inertia at this time is: Of these, n thermal power units are in operation, m wind and solar new energy units are in operation, and s CAES units are on standby. The system is operating stably.

[0039] Simulation Experiment 2: Due to cloud cover or insufficient wind, large-area load fluctuations occurred in the wind and solar turbine units within the system, resulting in active power disturbances and a load gap. The system frequency exhibits its maximum rate of change at this point. The inertia of the system at this time is: Where q≪m, based on simulation experiment 1, the system's moment of inertia decreases, and the required system inertia at this time is calculated: Calculate the system's inertia margin and inertia adequacy: in, for Moment of inertia at any given moment for System inertia margin at time 10:00 < 0, at this time, there is a shortage of system inertia, start the CAES unit, and calculate the system moment of inertia in real time: where x ≤ s. Calculate the value until it reaches 0 < ≤ 1%, at this time the system inertia meets the system operation requirements.

[0040] Calculate the weighted distribution ratio of active power regulation of the CAES unit according to the number of started units and its rated active power capacity in real time: where is the active power regulation weight of the Lth CAES unit, is the rated power of the Lth CAES unit, x is the number of CAES units started due to adjusting the moment of inertia in the system, 1 ≤ x < s, and s is the total number of CAES units in the regional power grid. [[ID=XX]] [[ID=XX]]

[0041] The active power regulation of the compressed air energy storage unit is: Through regulation, the rate of frequency change gradually decreases until it reaches 0 at time tn, at which time the system reaches the maximum frequency difference.

[0042] Calculate the inertia margin and adequacy and , and judge whether its interval meets ≥ 0 and 0 < ≤ 1%. If the condition is met, there is no need to continue starting the compressed air unit; if not, continue to start the CAES unit to maintain the moment of inertia until the compressed air energy storage system pulls back the frequency difference.

[0043] When the system frequency difference returns to the normal range, adjust the output of the thermal power unit according to the system needs, and gradually adjust the active power in the system until the CAES unit only maintains the spinning reserve to ensure the system moment of inertia, and wait for the wind and solar new energy units to resume operation.

[0044] After the system resumes stability, gradually cut off the CAES unit until the system returns to the previous operating state.

[0045] Example 4 is an embodiment of the present invention, illustrating a method for actively supporting grid inertia with an expandable generator set. It should be noted that the technical solution of this system for actively supporting grid inertia with an expandable generator set belongs to the same concept as the method described above. Details not described in detail in this embodiment can be found in the description of the method described above.

[0046] This embodiment also provides an electronic device applicable to a method for actively supporting grid inertia with an expandable generator set, comprising: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the method for actively supporting grid inertia with an expandable generator set as proposed in the above embodiment.

[0047] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements a method for actively supporting the grid inertia of an expansion generator set as proposed in the above embodiments.

[0048] The storage medium proposed in this embodiment and the method for realizing an active support of grid inertia by an expandable generator set proposed in the above embodiments belong to the same inventive concept. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.

[0049] Based on the above description of the implementation methods, those skilled in the art can clearly understand that the present invention can be implemented using software and necessary general-purpose hardware, and of course, it can also be implemented using hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk, or optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0050] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for actively supporting the inertia of a power grid using an expandable generator set, characterized in that: include, Install a power grid monitoring unit to collect voltage and current signals of the power grid in real time, calculate the frequency value of the power grid from the collected signals, and obtain power grid frequency data; By performing differential calculations on the acquired frequency data, the frequency difference and the rate of frequency change are obtained; Based on the operating status of generating units within the regional power grid, the upper and lower limits of the grid's moment of inertia and the system's adjustable moment of inertia resources are calculated in real time. Calculate the system's moment of inertia margin under the conditions of maximum frequency difference and maximum frequency change rate based on the frequency difference and the frequency change rate. The active power regulation of the compressed air energy storage unit is controlled based on the calculation results.

2. The method for actively supporting the grid inertia of an expandable generator set as described in claim 1, characterized in that: The calculation of the power grid frequency value includes installing a high-precision power grid monitoring unit at the power grid interface, connecting to the power grid through voltage transformers and current transformers, and collecting the voltage and current signals of the power grid in real time. The frequency value of the power grid is calculated from the acquired signal using the Fourier transform algorithm.

3. The method for actively supporting the grid inertia of an expandable generator set as described in claim 2, characterized in that: The differential calculation includes, after the power grid frequency acquisition module acquires the power grid frequency value, sending the frequency signal to the frequency difference and frequency change rate calculation module to calculate the frequency difference. and frequency change rate The relationship between frequency difference and rate of change of frequency is: in, It is a function of the rate of change of frequency over time.

4. The method for actively supporting the grid inertia of an expandable generator set as described in claim 3, characterized in that: The upper and lower limits for real-time calculation of the power grid's moment of inertia and the system's adjustable moment of inertia resources include real-time calculation of the system's moment of inertia, calculated using the following formula: in, Let i be the rated power of the i-th thermal power unit. Let be the inertial time constant of the i-th thermal power unit. Let be the start-stop coefficient of the i-th thermal power unit, which is 1 when starting and 0 when stopping; The rated power of the j-th new energy unit is Let be the inertial time constant of the j-th new energy unit. Let be the start-stop coefficient of the j-th new energy unit, which is 1 when starting and 0 when stopping; This is the rated power of the Lth CAES expander unit. Let L be the inertial time constant of the Lth CAES expander unit. is the start-up / shutdown coefficient of the Lth CAES expander unit, which is 1 when starting and 0 when stopping; n is the number of thermal power units, m is the number of new energy units, s is the number of CAES expander units in the regional power grid, and i, j, and L are variable indices. The upper and lower limits of the adjustable inertia resources of the regional power grid system are calculated. The upper limit is equal to the rotational inertia of the system when all units in the grid are running; the lower limit is equal to the rotational inertia of the system after all compressed air units are shut down.

5. The method for actively supporting the grid inertia of an expandable generator set as described in claim 4, characterized in that: The system rotational inertia margins for the cases of maximum frequency difference and maximum frequency change rate include, in At time 1, no frequency difference occurs. At this time, an active power disturbance occurs in the system, and the rate of frequency change is at its maximum. The system inertia that the system can withstand independently at the maximum rate of frequency change is... for: in, For system active power disturbance, for The rate of change of frequency at any given time is the maximum rate of change of frequency of the system. exist At time t, the frequency difference is at its maximum, and the rate of frequency change is 0. Then, the system inertia that can withstand the maximum frequency difference alone is... for: in, The system inertia is required to meet the maximum frequency difference that the system can withstand. This is the droop coefficient of the primary frequency modulation of the system. The system damping coefficient is... These are the mechanical characteristics of thermal power units / compressed air energy storage units and their comprehensive influence on the system frequency response. The time constant of the dynamic response of the generator frequency regulator of the synchronous unit within the system. The damping ratio is the frequency response process of the system that varies with time. It refers to the natural frequency in the dynamic frequency response process.

6. The method for actively supporting the grid inertia of an expandable generator set as described in claim 5, characterized in that: The calculation of the system rotational inertia margin under the conditions of maximum frequency difference and maximum frequency change rate also includes defining the system required inertia. for: exist This is the moment when the active disturbance occurs, at which point the rate of frequency change is at its maximum. Calculate the system inertia margin for the cases where the frequency difference reaches its maximum and the frequency change rate is at its maximum. : when When the value is ≥0, it indicates that the system margin is sufficient to meet the system inertia requirements. The thermal power unit adjusts its output according to the active power deviation, outputting or reducing active power to the system, and adjusting the frequency difference to stabilize the system. when A value less than 0 indicates insufficient system margin; the existing inertia does not meet the real-time inertia requirements of the system. In this case, the compressed air energy storage unit is started. When the system inertia margin... After the value reaches ≥0, the compressed air energy storage unit will then adjust the active power to eliminate active power disturbances.

7. The method for actively supporting the grid inertia of an expandable generator set as described in claim 6, characterized in that: The calculation of the system rotational inertia margin under the conditions of maximum frequency difference and maximum frequency change rate also includes defining the system inertia sufficiency. for: The range of system inertia margin is selected as 0 < ≤1%; when Under the condition of <0, the system starts the compressed air energy storage unit to make the real-time inertia meet the system's required inertia. At this time, the compressed air energy storage unit prioritizes frequency adjustment to adjust the frequency difference. Based on the number of compressed air energy storage units currently operating within the regional power grid, the corresponding active power regulation weighting ratio is determined according to the current rated installed capacity. The weighting is calculated as follows: in, The active power regulation weight of the Lth CAES unit. Let L be the rated power of the Lth CAES unit, and x be the number of CAES units started in the system due to the adjustment of rotational inertia, where 1 ≤ x. <s。 8. The method for actively supporting the grid inertia of an expandable generator set as described in claim 7, characterized in that: The control of the compressed air energy storage unit for active power regulation includes the active power regulation of the compressed air energy storage unit. for: when When ≥0, the sufficiency is judged to be 0< Is the ≤1% condition met? If sufficiency is 0 < If the condition of ≤1% is not met, CAES units are sorted by active power regulation weight coefficient from smallest to largest and then disconnected in order until the adequacy ratio is 0 < The condition of ≤1% is met.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of a method for actively supporting the grid inertia of an expansion generator set as described in any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of a method for actively supporting the inertia of a power grid using an expansion generator set, as described in any one of claims 1 to 8.

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