New energy and energy storage combined inertia supporting capacity modeling method under limitation of maximum frequency change rate of system

Abstract

The invention provides a new energy and energy storage combined inertia support capacity modeling method under the limitation of the maximum frequency change rate of a system, and belongs to the technical field of energy storage steady-state modeling, and the method comprises the steps: building a frequency dynamic response model for providing inertia support through cooperation of new energy and energy storage; constructing a system frequency change rate model under the combined action of the new energy and the stored energy; establishing a system maximum frequency change rate constraint when the new energy and the stored energy jointly provide inertia support; establishing a new energy and energy storage combined inertia supporting capability model; and the combined inertia support model is solved and analyzed by using commercial software. According to the method, a system maximum frequency change rate constraint model which can be incorporated into the influence of the new energy and energy storage combined inertia support is constructed, and the model can be used as an interface to be seamlessly integrated into a scheduling model of a power system, so that the stability and the regulation and control capability of the system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage steady-state modeling, and in particular to a method for modeling the combined inertia support capability of new energy and energy storage under the limitation of the maximum frequency change rate of a system. Background Art

[0002] With the transformation and upgrading of the global energy structure, the penetration rate of new energy in the power system continues to increase, and its impact on the stable operation of the power grid is becoming increasingly significant. The synchronous inertia level in the system is relatively reduced, which puts forward higher inertia requirements for the power system. In this context, it is particularly important to introduce new inertia resources and study the inertia support capacity of energy storage and other equipment.

[0003] Regarding the system inertia response and the inertia support provided by energy storage, a wealth of research results have been produced at home and abroad, such as Reference 1 "Analysis of inertia and inertia response characteristics in power system frequency dynamics" (Min Yong, Chen Lei, Liu Ruikuo). Proceedings of the CSEE, 2023, 43(03):855-868.) For the inertia or virtual inertia provided by different types of equipment in the power system, the impact of different inertias on the system frequency dynamics is analyzed from the perspective of physical principles and control. For the two ways of realizing virtual inertia response of grid-following equipment and grid-building equipment, the specific impact of the required energy storage resources and their control response delay on the system frequency dynamics is discussed. Reference 2 "Analysis of inertia demand for frequency stability of high-proportion renewable energy power system" (Zhang Guihong, Liu Fei, Wang Shibin). Journal of Electric Power Systems and Automation, 2022, 34(07):81-87.) Through the analysis of the system dynamic frequency response characteristics, the minimum inertia value required to maintain system stability is estimated, and the equivalent inertia time constant of the wind power-energy storage grid-connected system is calculated. On this basis, an inertia safety interval to ensure system frequency stability is constructed, and the intrinsic connection between system frequency stability and virtual inertia is deeply explained and quantitatively analyzed. Reference 3 "Energy storage virtual inertia active support and frequency regulation state transfer control" (Fu Yuan, Wan Yi, Zhang Xiangyu). Proceedings of the CSEE, 2024, 44(07): 2628-2641.) compares and analyzes the characteristic differences between the inherent inertia of conventional units, the virtual inertia of wind turbines and the energy storage inertia support, quantifies the virtual inertia of energy storage based on energy storage capacity configuration, and proposes an energy storage active support strategy that combines constant frequency control and frequency regulation state transfer control. Through the verification of the simulation system, the significant effect of this strategy in improving the performance of energy storage active support is demonstrated.

[0004] According to various research results, there have been many patent applications involving system inertia response and energy storage to provide inertia support. For example, Patent 1 "A virtual inertia control method for grid-type supercapacitor energy storage" (Wu Pengyue, Yang Peihao, Kou Shuichao, Guo Hao, Yin Yue, Li Jinghua, Sun Mengyao, Kang Zhen, Yan Yunfei, Li Zhipeng, Guo Xinyu, Guan Guozhang, Liu Pengfeng, Xue Guolong, Hu Shiming, Zhan Xinmin, Lin Kaijun, Liu Wenwu. CN116995693B, 2024-01-30.) An innovative grid-type supercapacitor energy storage virtual inertia control strategy, constructing a microgrid system integrating new energy and energy storage, deploying supercapacitors in this microgrid system, and introducing high-pass filter components, realizing precise control of the inertia of the new energy storage microgrid under the synergistic effect of supercapacitors and high-pass filters. Patent 2 "A method for configuring inertia to match the energy storage capacity of a virtual synchronous machine" (Yuan Chang, Liu Chang, Zhao Tianyang, Xie Peilin, Xiao Xiangning, Tang Niang. CN105762820B, 2018-11-09.) proposes an inertia optimization configuration method for the energy storage capacity of a virtual synchronous machine. Based on the rotor dynamic equation of the virtual synchronous machine and the mathematical expression of its output active power, a small signal dynamic model between the grid frequency and the output active power of the virtual synchronous machine is derived. Based on this model, the power upper limit required for the energy storage system can be calculated. Then, a matching strategy is proposed to determine the optimal ratio between the energy storage capacity of the virtual synchronous machine and its virtual inertia, providing methodological support for the in-depth application of virtual synchronous machine technology.

[0005] However, the research on the supporting capacity of new energy and energy storage inertia has the following deficiencies:

[0006] Most current research focuses on the control strategy level of renewable energy and energy storage systems in providing inertia support, while there is a relative lack of steady-state modeling of how they provide inertia support at the dispatch level. Building a model that incorporates the system's maximum frequency change rate constraint will help combine the inertia support capabilities of renewable energy and energy storage clusters with the steady-state operation of the system. Such a model can better evaluate and utilize the potential of renewable energy and energy storage systems in improving the stability of the power system.

[0007] In view of this, a modeling method for the combined inertia support capacity of renewable energy and energy storage under the limitation of the system's maximum frequency change rate is needed. Summary of the invention

[0008] In view of the problems existing in the prior art, the present invention provides a modeling method for the combined inertia support capacity of new energy and energy storage under the maximum frequency change rate limit of the system, which helps to combine the inertia support capacity of the new energy and energy storage cluster with the steady-state operation of the system. The specific technical solution is as follows:

[0009] A method for modeling the combined inertia support capability of new energy and energy storage under the maximum frequency change rate limit of the system, comprising the following steps:

[0010] S100, establish a frequency dynamic response model where new energy and energy storage work together to provide inertia support;

[0011] S200, construct a system frequency change rate model under the combined action of new energy and energy storage;

[0012] S300, establishing a maximum frequency change rate constraint for the system when new energy and energy storage jointly provide inertia support;

[0013] S400, establish a model for the combined inertia support capability of new energy and energy storage;

[0014] S500. Solve and analyze the combined inertia support model.

[0015] Preferably, in step S100, the frequency dynamic response model in which the new energy and energy storage cooperate to provide inertia support describes the nonlinear process of the frequency dynamic response through the swing equation of the system.

[0016] Preferably, in step S200, the system frequency change rate model under the combined action of new energy and energy storage is constructed based on the extreme scenario of the online unit with maximum system output losing load, combined with the frequency dynamic response model of the new energy and energy storage synergistically providing inertia support in S100.

[0017] Preferably, the system maximum frequency change rate constraint in step S300 is based on the system frequency change rate model under the combined action of new energy and energy storage in S200, and is established by setting the maximum limit of the system frequency change rate according to the safe operation standard of the power system.

[0018] Preferably, the model of the combined inertia support capability of new energy and energy storage includes the inertia model H of the new energy r , Inertia model of energy storage H s , the model of the combined inertia support capability of new energy and energy storage is expressed as follows:

[0019]

[0020] Among them, H tot The inertia level provided by the combination of new energy and energy storage, H r is the inertia of renewable energy r, H s is the inertia of the energy storage s.

[0021] Preferably, in step S500, commercial software is used to perform a solution to obtain an evaluation of the combined inertia support capability of new energy and energy storage.

[0022] Preferably, the swing equation is specifically used to describe the process, and the frequency dynamic response model is as follows:

[0023]

[0024] Among them, H syn Indicates the inertia level provided by the synchronous unit in the system, H tot represents the inertia level provided by new energy and energy storage in the system, f0 represents the rated frequency of the system, It represents the frequency change rate of the system, and ΔP represents the power shortage of the system.

[0025] Preferably, it is characterized in that the system power shortage model is expressed as follows:

[0026]

[0027] Among them, P g represents the active output of synchronous unit g, k g Indicates the maximum online unit number of the system.

[0028] Preferably, the system frequency change rate model under the combined action of new energy and energy storage is as follows:

[0029]

[0030] Where RoCoF represents the frequency change rate of the system, H g Represents the inertia of the synchronous unit g.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention can establish a steady-state model of the frequency dynamic behavior of the inertia support provided by new energy and energy storage, so as to more accurately describe and quantify the inertia support capacity of these resources.

[0033] 2. The present invention establishes a system maximum frequency change rate constraint, which fully considers the support capacity of new energy and energy storage clusters, and can be seamlessly integrated into the system operation model as a functional module. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0035] Figure 1 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0038] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0039] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0040] Example:

[0041] See also Figure 1 The modeling method of the combined inertia support capability of new energy and energy storage under the limitation of the maximum frequency change rate of the system in one embodiment of the present invention specifically includes the following steps:

[0042] S100, establish a frequency dynamic response model where new energy and energy storage work together to provide inertia support;

[0043] S200, construct a system frequency change rate model under the combined action of new energy and energy storage;

[0044] S300, establishing a maximum frequency change rate constraint for the system when new energy and energy storage jointly provide inertia support;

[0045] S400, establish a model for the combined inertia support capability of new energy and energy storage;

[0046] S500. Solve and analyze the combined inertia support model.

[0047] The following describes in detail steps S100 to S500 of the method for modeling the combined inertia support capability of new energy and energy storage under the limitation of the maximum frequency change rate of the system in this embodiment.

[0048] 1. Step S100, establishing a frequency dynamic response model in which new energy and energy storage cooperate to provide inertia support.

[0049] In this embodiment, the frequency dynamic response process of the new energy and energy storage cooperating to provide inertia support is characterized and modeled. This process is a nonlinear process, and the swing equation is specifically used to characterize the process. The frequency dynamic response model is as follows:

[0050]

[0051] Among them, H syn Indicates the inertia level provided by the synchronous unit in the system, H tot represents the inertia level provided by new energy and energy storage in the system, f0 represents the rated frequency of the system, It represents the frequency change rate of the system, and ΔP represents the power shortage of the system.

[0052] 2. Step S200, constructing a system frequency change rate model under the combined action of new energy and energy storage.

[0053] In this embodiment, a system power shortage ΔP model is constructed according to the N-1 principle. The model simulates the extreme situation of the maximum online unit losing load and is used as a typical test scenario for evaluating system frequency safety.

[0054] The system power shortage model is expressed as follows:

[0055]

[0056] Among them, P g represents the active output of synchronous unit g, k g Indicates the maximum online unit number of the system.

[0057] The frequency dynamic response model proposed in step S100 in which new energy and energy storage cooperate to provide inertia support is combined to construct a system frequency change rate model under the combined action of new energy and energy storage as follows:

[0058]

[0059] Where RoCoF represents the frequency change rate of the system, H g Represents the inertia of the synchronous unit g.

[0060] 3. Step S300, establishing a system maximum frequency change rate constraint when new energy and energy storage jointly provide inertia support.

[0061] In this embodiment, the maximum value of the system frequency change rate occurs when the disturbance first occurs. By limiting the maximum frequency change rate of the system within a certain range, a connection between the inertia level and the system frequency stability can be established.

[0062] Among them, the upper limit of the system frequency change rate RoCoF max It is set according to the safe operation standards of the power system.

[0063] In this embodiment, the maximum frequency change rate constraint of the system when the new energy and energy storage jointly provide inertia support is expressed as follows:

[0064] RoCoF≤RoCoF max .

[0065] 4. Step S400, establishing a model of the combined inertia support capability of new energy and energy storage.

[0066] In this embodiment, the model of the combined inertia support capability of new energy and energy storage includes the inertia model H of the new energy r , Inertia model of energy storage H s The model of the combined inertia support capacity of new energy and energy storage is expressed as follows:

[0067] H tot =∑rH r +∑ s H s .

[0068] Among them, H tot The inertia level provided by the combination of new energy and energy storage, H r is the inertia of renewable energy r, H s is the inertia of the energy storage s.

[0069] 5. Step S500, using commercial software to solve and analyze the combined inertia support model.

[0070] In this embodiment, the new energy and energy storage combined inertia support capability model under the system maximum frequency change rate limit describes the inertia support service provided by new energy and energy storage in the frequency dynamic response process, and can be connected to the system operation model as a steady-state model.

[0071] In this embodiment, commercial software is used to solve the operation model connected to the combined inertia support model, which can effectively evaluate the combined inertia support capability of new energy and energy storage under the maximum frequency change rate limit of the system.

[0072] In summary, the present invention can achieve steady-state modeling of the frequency dynamic behavior of the inertia support provided by the new energy and energy storage, thereby more accurately describing the inertia support characteristics of the new energy and energy storage cluster. On this basis, the present invention also establishes a constraint on the maximum frequency change rate of the system when considering the inertia support of the new energy and energy storage. This constraint can be seamlessly integrated into the system operation model as a key interface. Therefore, this application successfully solves many deficiencies in the prior art and demonstrates extremely high industrial application value and potential.

[0073] Those of ordinary skill in the art will appreciate that the units of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition of each example has been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0074] In the embodiments provided by the present invention, it should be understood that the division of units is only a logical function division, and there may be other division methods in actual implementation, for example, multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored, etc.

[0075] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0076] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-0nlyMemory), random access memory (RAM, RandomAccessMemory), mobile hard disk, magnetic disk or optical disk, etc., which can store program code.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A modeling method for the combined inertia support capability of new energy and energy storage under the maximum frequency change rate limit of the system, characterized in that: The following steps are involved: S100, establish a frequency dynamic response model where new energy and energy storage work together to provide inertia support; S200, construct a system frequency change rate model under the combined action of new energy and energy storage; S300, establishing a maximum frequency change rate constraint for the system when new energy and energy storage jointly provide inertia support; S400, establish a model for the combined inertia support capability of new energy and energy storage; S500. Solve and analyze the combined inertia support model.

2. The modeling method for the combined inertia support capability of new energy and energy storage under the maximum frequency change rate limit of the system according to claim 1 is characterized in that: In step S100, the frequency dynamic response model in which the new energy and energy storage cooperate to provide inertia support describes the nonlinear process of frequency dynamic response through the swing equation of the system.

3. The method for modeling the combined inertia support capability of new energy and energy storage under the maximum frequency change rate limit of the system according to claim 1 is characterized in that: In step S200, the system frequency change rate model under the combined action of new energy and energy storage is constructed based on the extreme scenario of the online unit with maximum system output losing load, combined with the frequency dynamic response model of the new energy and energy storage synergistically providing inertia support in S100.

4. The method for modeling the combined inertia support capability of new energy and energy storage under the maximum frequency change rate limit of the system according to claim 1 is characterized in that: The system maximum frequency change rate constraint in step S300 is based on the system frequency change rate model under the combined action of new energy and energy storage in S200, and is established by setting the maximum limit of the system frequency change rate according to the safe operation standard of the power system.

5. The method for modeling the combined inertia support capability of new energy and energy storage under the maximum frequency change rate limit of the system according to claim 1 is characterized in that: The model of the combined inertia support capability of new energy and energy storage includes the inertia model H of new energy r , Inertia model of energy storage H s , the model of the combined inertia support capability of new energy and energy storage is expressed as follows: Among them, H tot The inertia level provided by the combination of new energy and energy storage, H r is the inertia of renewable energy r, H s is the inertia of the energy storage s.

6. The method for modeling the combined inertia support capability of new energy and energy storage under the maximum frequency change rate limit of the system according to claim 1 is characterized in that: In step S500, commercial software is used to solve and obtain an evaluation of the combined inertia support capability of new energy and energy storage.

7. The method for modeling the combined inertia support capability of new energy and energy storage under the maximum frequency change rate limit of the system according to claim 2 is characterized in that: The swing equation is used to describe the process, and the frequency dynamic response model is as follows: Among them, H syn Indicates the inertia level provided by the synchronous unit in the system, H tot represents the inertia level provided by new energy and energy storage in the system, f0 represents the rated frequency of the system, It represents the frequency change rate of the system, and ΔP represents the power shortage of the system.

8. The method for modeling the combined inertia support capability of new energy and energy storage under the maximum frequency change rate limit of the system according to claim 7, characterized in that: The system power shortage model is expressed as follows: Among them, P g represents the active output of synchronous unit g, k g Indicates the maximum online unit number of the system.

9. The method for modeling the combined inertia support capability of new energy and energy storage under the maximum frequency change rate limit of the system according to claim 7 is characterized in that: The system frequency change rate model under the combined action of new energy and energy storage is as follows: Where RoCoF represents the frequency change rate of the system, H g Represents the inertia of the synchronous unit g.

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