A new power system inertia demand evaluation and configuration method and system

Abstract

The present application provides a new type of power system inertia demand evaluation and configuration method, based on system capacity-inertia data to calculate the equivalent inertia of the system, considering the primary frequency modulation dead zone constraint, the maximum frequency change rate constraint condition and the whole process maximum frequency deviation constraint condition, to obtain the minimum inertia demand of the system. Combined with the total equivalent inertia of the system and the minimum inertia demand of the system, the system inertia shortage is accurately calculated, and finally the shortage inertia is optimized and configured. Compared with the traditional method, this method realizes the accurate solution of the minimum inertia in the complex environment of multiple constraints, effectively breaks through the traditional limitations, and provides a new technical idea for the inertia planning and optimization configuration of the new type of power system.

Description

Technical Field

[0001] This invention relates to the field of power system frequency regulation technology, and in particular to a novel method and system for assessing and configuring power system inertia requirements. Background Technology

[0002] In the current development trend of the power industry, the importance of power system inertia, as a core supporting element for maintaining grid frequency stability and effectively resisting active power disturbances, is increasing day by day. Accurate and scientific assessment of system inertia requirements is crucial for ensuring that the frequency drop depth and rate of change are strictly controlled within safe thresholds during power system fault transients. It has become an important prerequisite for many tasks such as grid planning, operation scheduling, and safety control, and plays a vital role in further improving the power supply reliability and operational resilience of new power systems.

[0003] A deeper analysis of current mainstream methods for assessing and configuring system inertia requirements reveals several limitations. Most methods still rely on traditional power grid models for calculations, often considering only single constraints such as frequency change rate or steady-state frequency deviation, failing to comprehensively and accurately reflect the actual operating conditions of the power system. Furthermore, the modeling process often simplifies the dead-zone characteristics of primary frequency regulation, neglecting its complex role in actual frequency regulation, thus failing to fully account for the dynamic frequency changes throughout the transient process. Inertia configuration generally adopts empirical values ​​and fixed-quota configurations. This approach lacks specific analysis of different power grid operating scenarios and conditions, and cannot make flexible adjustments based on real-time changes in the power grid, resulting in significantly reduced calculation accuracy. With a high proportion of new energy sources integrated into the grid, the operating characteristics of the power system have become increasingly complex. The intermittent and fluctuating characteristics of new energy sources pose new challenges to the frequency stability of the power grid. Traditional methods for assessing and configuring system inertia requirements are inadequate in addressing these new changes and struggle to meet the development needs of new power systems. Therefore, there is an urgent need for a more scientific, accurate method for assessing and configuring system inertia requirements that can adapt to the complex operating characteristics of power grids. Summary of the Invention

[0004] To achieve the above objectives, this invention provides a novel method for assessing and configuring inertia requirements in a power system, specifically including the following steps: Step 1: Collect the capacity-inertia data of the system to be evaluated and configured, and calculate the equivalent inertia of the system based on the capacity-inertia data; Step 2: Considering the dead zone constraint of the first frequency modulation, calculate the system inertia requirement before the first frequency modulation under the constraint of the maximum rate of change of the system frequency and the system inertia requirement after the first frequency modulation under the constraint of the maximum frequency deviation. Based on the maximum value of the system inertia requirements before and after the first frequency modulation, obtain the minimum system inertia requirement. Step 3: Calculate the system inertia gap based on the system's equivalent inertia and the system's minimum inertia requirement, and decide whether to allocate inertia resources.

[0005] Preferably, the capacity-inertia data in step 1 includes the capacity and inertia constant of the synchronous generator, the capacity and equivalent inertia coefficient of the new energy source (wind power / photovoltaic) with inertia support function, and the capacity of the energy storage system with inertia support function. S ESS And the equivalent inertia coefficient, the capacity and equivalent inertia coefficient of a flexible DC transmission system with inertia support function, and the capacity and equivalent inertia coefficient of an asynchronous motor.

[0006] Preferably, in step 1, the total equivalent inertia of the system is calculated based on the above-mentioned basic data, specifically as follows: In the formula, S G For the capacity of the synchronous generator, H G It is the inertial constant. S RES For the capacity of new energy sources (wind power / solar power) with inertia support function, H RES The equivalent inertia coefficient, S ESS For the capacity of energy storage systems with inertia support function, H ESS The equivalent inertia coefficient, S HVDC To provide capacity for flexible DC transmission systems with inertia support capabilities, H HVDC The equivalent inertia coefficient, S IM For the capacity of the asynchronous motor, H IM The equivalent inertia coefficient is denoted as , where N G , N RES , N ESS , N HVDC and N IMThe quantities of equipment are as follows: synchronous generators, new energy sources with inertia support, energy storage systems with inertia support, flexible DC transmission systems with inertia support, and asynchronous motors.

[0007] Preferably, the basic equations of rotor motion for the primary frequency modulation effect of the system, considering the primary frequency modulation dead zone constraint, in step 2 are as follows: In the formula, E Δ is the equivalent inertia of the system. f The frequency deviation is obtained by subtracting the system's actual frequency from its rated frequency. f N dΔ is the rated value of the frequency. f / dt is the rate of change of frequency, Δ P This is due to a shortfall in active power. f db This is a frequency modulation dead zone. K This is the frequency modulation coefficient.

[0008] Preferably, in step 2, the system inertia requirement before the primary frequency regulation is calculated based on the maximum active power deficit, the rated value of the frequency, and the maximum frequency change rate; the system inertia requirement before the primary frequency regulation is calculated based on the maximum active power deficit, the primary frequency regulation dead zone constraint, the maximum frequency deviation constraint, and the rated value of the frequency; and the minimum inertia requirement is obtained by considering the dual constraints of the maximum frequency change rate and the maximum frequency deviation and finding the maximum system inertia requirement before and after the primary frequency regulation.

[0009] Preferably, in step 2, the calculation of the system inertia requirement before the first frequency modulation under the constraint of the maximum frequency change rate is specifically as follows: In the formula, The system inertia requirement before a single frequency modulation operation, Δ P max This is the maximum active power deficit. Maximum rate of change constraint; Preferably, in step 2, the system inertia requirement after the next frequency modulation is calculated under the maximum frequency deviation constraint. Specifically: In the formula, This refers to the system inertia requirement after a single frequency modulation operation.

[0010] Preferably, the calculation of the minimum inertia requirement of the system in step 2 is specifically as follows: In the formula, This represents the minimum inertia requirement for the current system.

[0011] Preferably, the calculation of the equivalent inertia gap of the system in step 3 is specifically as follows: In the formula, This is the equivalent inertia gap of the system. This is the total equivalent inertia of the system.

[0012] Preferably, in step 3, if the system's equivalent inertia gap is ≤0, no additional inertia resources need to be configured; if the system's equivalent inertia gap is >0, then additional inertia resources need to be configured.

[0013] Compared with existing technologies, the advantages of this invention are as follows: Traditional power grid inertia assessment and configuration methods mostly rely on simplified traditional power grid models for calculations. These methods not only idealize and simplify the primary frequency regulation dead zone but also generally depend on manually set quota values ​​to complete inertia configuration. They fail to incorporate the actual dynamic effects of the primary frequency regulation dead zone into the calculation system and only use a single frequency constraint as a verification standard. The resulting inertia requirements often deviate significantly from the actual operating characteristics of the power grid, making it difficult to adapt to the complex operating states of new power systems. This invention overcomes these limitations by fully incorporating the actual dynamic response characteristics of the primary frequency regulation dead zone into the calculation framework. Simultaneously, it constructs a dual constraint system including the maximum frequency change rate and the maximum frequency deviation throughout the transient process, enabling accurate calculation of the minimum inertia requirement for system operation under multiple constraint conditions. Based on this, the technology can combine the real-time measurement results of the current total equivalent inertia of the power grid to quickly locate the inertia deficit in the system, thereby completing targeted optimization and configuration of inertia resources. Compared with traditional solutions, the calculation accuracy of this invention is significantly improved. It fully takes into account the details of frequency dynamic changes throughout the entire transient process under large disturbances, and can accurately match the complex operating characteristics of the power grid after a large-scale integration of high proportion of new energy. It is not only suitable for traditional power grid scenarios dominated by conventional synchronous generators, but also covers a variety of special operating conditions such as high proportion of new energy power grids, weak sending-end power grids, and isolated microgrids. It effectively fills the application gap of traditional technologies in complex scenarios and greatly expands the scope of application. Attached Figure Description

[0014] 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.

[0015] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0018] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. Where the terms "first," "second," and "third" are used for descriptive purposes and to distinguish technical features, they should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the sequential relationship of the indicated technical features.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0020] The present invention proposes a novel method for assessing and configuring inertia requirements in a power system. The specific implementation steps are described below: 1) Collect data from the systems to be evaluated, including data related to synchronous generators, new energy sources (wind power / photovoltaics), energy storage, flexible DC transmission, and asynchronous motors; 2) Calculate the equivalent inertia of the current system; 3) Considering the dead zone of primary frequency modulation, calculate the minimum inertia requirement of the system under the constraints of maximum frequency change rate and maximum frequency deviation. 4) Calculate the system inertia gap. If the system inertia is insufficient, allocate additional inertia resources.

[0021] Specifically, in step 1), relevant data of the system whose inertia requirement needs to be evaluated are collected through methods such as equipment nameplate parameters, control parameters, or offline simulation tests, including the capacity of the synchronous generator. S G and inertial constant H G The capacity of new energy sources (wind power / solar power) with inertia support function S RES and equivalent inertia coefficient H RES The capacity of energy storage systems with inertia support function S ESS and equivalent inertia coefficient H ESS The capacity of flexible DC transmission systems with inertia support function S HVDC and equivalent inertia coefficient H HVDC asynchronous motor capacity S IM and equivalent inertia coefficient H IM .

[0022] Specifically, in step 2), the current system's total equivalent inertia E sys The calculation method is as follows: in, N G , N RES , N ESS , N HVDC and N IM The quantities of equipment are as follows: synchronous generators, new energy sources with inertia support, energy storage systems with inertia support, flexible DC transmission systems with inertia support, and asynchronous motors.

[0023] Specifically, in step 3), the entire network of generating units, loads, and power electronic equipment are modeled as single units, resulting in the following basic equation of rotor motion considering the primary frequency regulation effect of the system: in, E Δ is the equivalent inertia of the system. f The frequency deviation is obtained by subtracting the system's actual frequency from its rated frequency. f N dΔ is the rated value of the frequency. f / dt (can also be written as / dt) ) represents the rate of change of frequency, Δ P This is due to a shortfall in active power. f db This is a frequency modulation dead zone. K This is the frequency modulation coefficient.

[0024] The following considers the system's maximum frequency change rate. Constraints and maximum frequency deviation Δ f max Constraints are used to determine the minimum inertia requirement of the system.

[0025] The analysis focuses on the most severe disturbance conditions that the system may experience (e.g., DC bipolar blocking), and the maximum active power deficit that the system may experience is preset to be Δ. P max At the instant of the disturbance, the system's first frequency adjustment has not yet started, and the system's frequency change rate is at its maximum. At this time, the calculated system inertia requirement is: When a disturbance occurs in the system, the frequency deviation must not exceed the maximum allowable frequency deviation Δ throughout the entire frequency change process. f max The constraints divide the perturbed process into two stages: Stage 1: The system frequency drops from the rated value to the primary frequency modulation dead zone boundary. During this process, the primary frequency modulation does not operate. Substituting ΔPmax into equation (2), we can obtain the system frequency change rate during this process as follows: (4) Integrating equation (4), we can obtain the time-domain expression for the stage-one frequency deviation as follows: Assuming the time it takes for the frequency to cross the frequency dead zone boundary once is t 1, that is t = t At time 1, Δ f 1( t 1)=- f db Substituting into equation (5), we get: Phase Two: The system performs a frequency adjustment operation until the frequency reaches its minimum value, then Δ... P max Substituting into equation (2), we can obtain the rate of change of the system frequency during this process: Using equation (6) as the initial value for equation (7), and solving equation (7), we obtain the time-domain expression for the stage two frequency deviation: The lowest frequency point must satisfy a frequency deviation of no more than Δ. f max Given the constraints, the system inertia requirement can be obtained as follows: The minimum inertia requirement of the system under the dual constraints of maximum frequency change rate and maximum frequency deviation is: Specifically, in step 4), the equivalent inertia gap of the current system is calculated: If Δ E If ≤0, then no additional inertia resources need to be configured; if Δ E If the value is greater than 0, additional inertia resources are required. Taking grid-type energy storage as an example, the additional configuration capacity is... S x The equivalent inertia coefficient is H x For grid-type energy storage systems, the system parameters must meet the following conditions: Those skilled in the art will recognize that the units of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the invention.

[0026] In the embodiments provided by this invention, it should be understood that the division of units is merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units may be combined into one unit, one unit may be split into multiple units, or some features may be ignored. Furthermore, the functional units in the various embodiments of this 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 integrated unit described above can be implemented in hardware or as a software functional unit.

[0027] If the integrated unit is implemented as 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. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0028] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A novel method for assessing and allocating inertia requirements in a power system, characterized in that, Specifically, the steps include the following: Step 1: Collect the capacity-inertia data of the system to be evaluated and configured, and calculate the equivalent inertia of the system based on the capacity-inertia data; Step 2: Considering the dead zone constraint of the first frequency modulation, calculate the system inertia requirement before the first frequency modulation under the constraint of the maximum rate of change of the system frequency and the system inertia requirement after the first frequency modulation under the constraint of the maximum frequency deviation. Based on the maximum value of the system inertia requirements before and after the first frequency modulation, obtain the minimum system inertia requirement. Step 3: Calculate the system inertia gap based on the system's equivalent inertia and the system's minimum inertia requirement, and decide whether to allocate inertia resources.

2. The novel power system inertia demand assessment and configuration method according to claim 1, characterized in that, The capacity-inertia data mentioned in step 1 includes the capacity and inertia constant of synchronous generators, the capacity and equivalent inertia coefficient of new energy sources (wind power / photovoltaic) with inertia support function, and the capacity of energy storage systems with inertia support function. S ESS And the equivalent inertia coefficient, the capacity and equivalent inertia coefficient of a flexible DC transmission system with inertia support function, and the capacity and equivalent inertia coefficient of an asynchronous motor.

3. The novel power system inertia demand assessment and configuration method according to claim 1 or 2, characterized in that, Step 1 calculates the total equivalent inertia of the system based on the above basic data, specifically as follows: In the formula, S G For the capacity of the synchronous generator, H G It is the inertial constant. S RES For the capacity of new energy sources (wind power / solar power) with inertia support function, H RES The equivalent inertia coefficient, S ESS For the capacity of energy storage systems with inertia support function, H ESS The equivalent inertia coefficient, S HVDC To provide capacity for flexible DC transmission systems with inertia support capabilities, H HVDC The equivalent inertia coefficient, S IM For the capacity of the asynchronous motor, H IM The equivalent inertia coefficient is denoted as , where N G , N RES , N ESS , N HVDC and N IM The quantities of equipment are as follows: synchronous generators, new energy sources with inertia support, energy storage systems with inertia support, flexible DC transmission systems with inertia support, and asynchronous motors.

3. The novel power system inertia demand assessment and configuration method according to claim 1, characterized in that, in step 2, the basic equation of rotor motion considering the primary frequency regulation dead zone constraint to establish the primary frequency regulation effect of the system is specifically as follows: In the formula, E Δ is the equivalent inertia of the system. f The frequency deviation is obtained by subtracting the system's actual frequency from its rated frequency. f N dΔ is the rated value of the frequency. f / dt is the rate of change of frequency, Δ P This is due to a shortfall in active power. f db This is a frequency modulation dead zone. K This is the frequency modulation coefficient.

4. The novel power system inertia demand assessment and configuration method according to claim 1, characterized in that, In step 2, the system inertia requirement before the primary frequency regulation is calculated based on the maximum active power deficit, the rated frequency, and the maximum frequency change rate. The system inertia requirement before the primary frequency regulation is also calculated based on the maximum active power deficit, the primary frequency regulation dead zone constraint, the maximum frequency deviation constraint, and the rated frequency. The minimum inertia requirement is obtained by considering the dual constraints of the maximum frequency change rate and the maximum frequency deviation and finding the maximum system inertia requirement before and after the primary frequency regulation.

5. The novel power system inertia demand assessment and configuration method according to claim 4, characterized in that, Step 2 involves calculating the system inertia requirement before the next frequency modulation under the constraint of the maximum rate of frequency change. Specifically: In the formula, The system inertia requirement before a single frequency modulation operation, Δ P max This is the maximum active power deficit. The maximum rate of change of frequency is constrained.

6. The novel power system inertia demand assessment and configuration method according to claim 5, characterized in that, Step 2 involves calculating the system inertia requirement after the next frequency modulation under the maximum frequency deviation constraint. Specifically: In the formula, This refers to the system inertia requirement after a single frequency modulation operation.

7. The novel power system inertia demand assessment and configuration method according to claim 6, characterized in that, Step 2 involves calculating the minimum inertia requirement of the system as follows: In the formula, This represents the minimum inertia requirement for the current system.

8. The novel power system inertia demand assessment and configuration method according to claim 7, characterized in that, Step 3 involves calculating the equivalent inertia gap of the system, specifically as follows: In the formula, This is the equivalent inertia gap of the system. This is the total equivalent inertia of the system.

9. The novel power system inertia demand assessment and configuration method according to claim 1, characterized in that, In step 3, if the system's equivalent inertia gap is ≤0, no additional inertia resources need to be configured; if the system's equivalent inertia gap is >0, additional inertia resources need to be configured.

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