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CN-122026404-A - Frequency support capacity quantitative evaluation method and system for new energy power system based on frequency band analysis

CN122026404ACN 122026404 ACN122026404 ACN 122026404ACN-122026404-A

Abstract

The invention discloses a frequency support capacity quantitative evaluation method and system of a new energy power system based on frequency band analysis. Aiming at the frequency response difference of multiple types of power generation equipment in a new energy power system, a unified system frequency response model is established in a frequency domain, and the frequency support capability of the power generation equipment in different frequency bands is quantified by adopting a frequency band analysis method. The method comprises the steps of establishing a frequency response transfer function matrix based on a linearization dynamic equation of a multi-machine system, calculating a frequency band H 2 /H ∞ norm index in a selected frequency range to quantitatively represent the stability performance of the system in inertia response and primary frequency modulation stages, and realizing the comparison of different equipment and frequency supporting capacities among the systems through the normalization processing of the system reference capacity and the frequency. The invention can accurately reveal the response difference and contribution of the synchronous machine and the wind-solar energy storage power electronic interface power supply in each frequency band, and provides a unified and effective frequency domain analysis method for frequency modulation control design and frequency stability evaluation of a new energy power system.

Inventors

  • WANG ZHEN
  • CAI YIFAN
  • SHAN YU

Assignees

  • 浙江大学

Dates

Publication Date
20260512
Application Date
20260416

Claims (10)

  1. 1. The new energy power system frequency support capacity quantitative evaluation method based on frequency band analysis is characterized by comprising the following steps of: 1) Establishing a frequency dynamic model based on parameter information of a wind-solar energy storage power electronic interface power supply comprising a synchronous machine, a grid-connected converter and a grid-following converter in a new energy power system; 2) Combining a network topology structure of the power system and a power relation among nodes, and constructing a multi-machine system transfer function matrix capable of representing a mapping relation between input power disturbance and node frequency response based on the frequency dynamic model; 3) Selecting a system global or target node as an analysis object according to the evaluation requirement, and determining a corresponding dynamic transfer relationship; 4) Setting a target frequency interval, and calculating a frequency band H 2 /H ∞ norm index of the analysis object in the frequency interval based on the multi-machine system transfer function matrix so as to represent the frequency supporting capability of the system to power disturbance; 5) And carrying out capacity normalization and frequency normalization processing on the norm indexes so as to realize the comparison and evaluation of the frequency supporting capability among different equipment and different systems.
  2. 2. The method for quantitatively evaluating the frequency supporting capacity of the new energy power system based on the frequency band analysis according to claim 1 is characterized in that the step 1) is specifically that small disturbance linearization processing is carried out on a synchronous machine swinging equation, a net-structured converter virtual synchronous control equation and a net-structured converter phase-locked loop dynamic equation near a steady-state working point.
  3. 3. The method for quantitatively evaluating the frequency supporting capacity of the new energy power system based on the frequency band analysis of claim 1, wherein the step 2) specifically comprises the steps of combining a power system network topology structure and a power relation among nodes, establishing a multi-machine system transfer function matrix to represent a mapping relation between input power disturbance and node frequency response, wherein the mapping relation is expressed as follows: , The system comprises a system network matrix, a node admittance matrix, a network topology structure, a node admittance matrix and a node dynamic matrix, wherein s is a Laplacian operator, omega 0 is an angular frequency reference value and meets omega 0 =2πf 0 ,f 0 as a reference frequency, delta omega represents angular frequency change of each node in the system, the system comprises a synchronous machine, a grid-built converter, angle change vector delta omega SG 、Δω GFM 、Δω GFL of each internal node of the grid-built converter and angle change vector delta omega NI ;ΔP L of each non-internal node, the angle change vector delta omega SG 、Δω GFM 、Δω GFL is power disturbance, delta P LSG 、ΔP LGFM 、ΔP LGFL and delta P LNI are corresponding power disturbance vectors of each node respectively, H(s) represents the sum of the system network matrix and the device matrix, H(s) =L(s) +G(s), L(s) is the system network matrix and is obtained by deduction of a node admittance matrix and a network topology structure, G(s) is the device dynamic matrix of the synchronous machine, the grid-built converter and the grid-built converter comprises inertia and damping terms of the synchronous machine, virtual and damping control terms of the grid-built converter and the grid-built converter, the frequency response control terms are obtained through device parameters, and running data or simulation, and N represents the total number of power element j represents the node dynamic inertia of the node j in the system, and the node dynamic relation of the node j (j) represents the node change of the system.
  4. 4. The method for quantitatively evaluating the frequency support capability of the new energy power system based on the frequency band analysis according to claim 3, wherein the step 3) selects a system global or target node as an analysis object according to the evaluation requirement, and determines a corresponding dynamic transfer relationship, specifically: Let T(s) be the selected analysis object, T(s) =h(s) be the global index, and T(s) =h i eq (s),H i eq (s) be the node index, represent the disturbance input to the equivalent dynamic channel of the i-th node angular frequency response.
  5. 5. The method for quantitatively evaluating the frequency support capability of a new energy power system based on frequency band analysis according to claim 4, wherein the step 4) sets a target frequency interval, calculates a frequency band H 2 /H ∞ norm index of the analysis object in the frequency interval based on the multi-machine system transfer function matrix to characterize the frequency support capability of the system to power disturbance, and the calculation is expressed as: , Wherein tr (x) represents the trace of the analysis object corresponding matrix, and the superscript "H" represents the conjugate transpose; The maximum singular value of the corresponding matrix of the analysis object is shown in the table, (), ω up and ω low are the upper and lower boundaries of the angular frequency of the selected frequency band, sup is the upper boundary, and T (jω) is the frequency response of the analysis object T(s) at s=jω.
  6. 6. The method for quantitatively evaluating the frequency supporting capability of the new energy power system based on the frequency band analysis according to claim 1, wherein the capacity and the frequency normalization processing is performed on the obtained frequency band norms in the step 5), so that the unified evaluation of the frequency supporting capability under different system scales and equipment configuration conditions is realized, and the method is specifically: The capacity normalization is performed based on the rated capacity of the system, and the frequency normalization is performed based on the reference frequency to eliminate the influence of different system scales and running conditions, namely, the frequency band H 2 /H ∞ norm index obtained in the step 4) 、 Further correcting the norm of the corrected frequency band H 2 /H ∞ 、 The calculation formula is as follows: , Wherein, the Is the sum of active disturbances at the system reference capacity, Is the system reference frequency.
  7. 7. The method for quantitatively evaluating the frequency supporting capability of the new energy power system based on the frequency band analysis according to claim 1, wherein in the step 4), the frequency range is divided into a low frequency band, a medium frequency band and a high frequency band according to the frequency dynamic characteristics of the power system, wherein: 1) Less than 0.1Hz, dividing the inertial support device into low frequency bands for representing inertial support capacity; 2) Dividing the frequency into a middle frequency range of 0.1Hz-10Hz for representing primary frequency modulation capability; 3) Dividing the frequency range into high frequency ranges which are used for representing control response capacity; H 2 /H ∞ norm indexes in each frequency interval are calculated respectively, so that the sectional quantitative evaluation of the frequency supporting capability under different dynamic mechanisms is realized.
  8. 8. A new energy power system frequency support capability quantitative assessment system based on frequency band analysis, wherein the method of any one of claims 1-7 is implemented, the system comprising: The frequency dynamic model building module is used for building a system frequency dynamic model based on parameter information of a wind-solar energy storage power electronic interface power supply of a new energy power system, wherein the parameter information comprises a synchronous machine, a grid-connected converter and a grid-following converter; The transfer function matrix construction module is used for constructing a multi-machine system transfer function matrix capable of representing the mapping relation between input power disturbance and node frequency response based on the frequency dynamic model by combining the power system network topological structure and the power relation among nodes; The analysis object selection module is used for selecting a system global or target node as an analysis object according to the evaluation requirement and determining a dynamic transfer relationship corresponding to the analysis object; The frequency band H 2 /H ∞ norm calculation module is used for setting a target frequency interval and calculating a frequency band H 2 /H ∞ norm index of the analysis object in the frequency interval based on the multi-machine system transfer function matrix so as to represent the frequency supporting capacity of the system on power disturbance; And the normalization processing module is used for carrying out capacity and frequency normalization processing on the obtained indexes and realizing the comparison of the frequency supporting capacities among different devices and systems.
  9. 9. An electronic device, comprising: one or more processors; A memory for storing one or more programs; The one or more programs, when executed by the one or more processors, cause the one or more processors to implement the method of any of claims 1-7.
  10. 10. A computer readable storage medium storing computer executable instructions which, when executed, are adapted to carry out the method of any one of claims 1 to 7.

Description

Frequency support capacity quantitative evaluation method and system for new energy power system based on frequency band analysis Technical Field The invention belongs to the field of novel power system stability analysis, and particularly relates to a frequency support capacity quantitative evaluation method and system for a new energy power system based on frequency band analysis, which can be used for frequency support capacity quantitative analysis of a hybrid system of power electronic interface power supplies including wind power, photovoltaic, energy storage and the like. Background Along with the high-proportion access of renewable energy sources such as wind power, photovoltaic and the like, the total inertia level of the power system is obviously reduced, and the frequency dynamic characteristic presents complex characteristics of multi-time scale and multi-node distribution. Conventional time domain analysis methods typically rely on simulations of the post-disturbance frequency trace, but it is difficult to fully reflect the stability of the system at different time scales. In particular, a large number of power electronics are used in the power system, and the frequency response thereof varies significantly, which makes it difficult for conventional methods to accurately describe the supporting effect of these devices on frequency fluctuations. The prior art establishes a multi-machine system frequency response equation based on a synchronous machine model for analyzing initial power allocation and inertia response characteristics. The method can describe the dynamic difference at the initial stage of the fault, but only covers a short time window from the beginning of the disturbance to the lowest frequency point, and cannot reflect the integral frequency stability characteristic of the primary frequency modulation stage. In addition, the existing researches mostly unify the frequency modulation dynamics of all power generation equipment into a damping-speed regulator-inertia form, but fail to fully consider the difference among heterogeneous power generation equipment. The grid-type converter provides inertia and damping support through droop control or virtual synchronous machine control, and frequency detection is realized by relying on a phase-locked loop with the grid-type converter, and the frequency response of the grid-type converter has obvious hysteresis in a transient phase. Time domain simulations can demonstrate this difference, but it is difficult to quantitatively analyze its contribution to the system frequency support capability. In contrast, the system norm analysis method based on the frequency domain can characterize the system disturbance rejection performance from the input-output response angle. By calculating the H 2/H∞ norm, the system's ability to absorb or reject disturbance energy can be quantified. However, the conventional full-band norm cannot distinguish between the inertia response and the frequency dynamic characteristics of the primary frequency modulation stage, and it is difficult to reflect the real performance of the system at different time scales. Therefore, the invention provides a frequency support capacity quantization evaluation method for a new energy power system based on frequency band analysis, which realizes frequency dynamic quantization under different time scales. Disclosure of Invention In order to overcome the defects, the invention provides a frequency support capacity quantitative evaluation method and system for a new energy power system based on frequency band analysis. According to the method, the frequency response energy index is calculated in a target frequency band through frequency domain decomposition of a system transfer function matrix, and the frequency supporting capacity of power generation equipment in different frequency bands to the global or node is quantitatively represented, so that quantitative analysis of frequency stability is realized. The technical scheme of the invention comprises the following steps: a new energy power system frequency support capacity quantitative evaluation method based on frequency band analysis comprises the following steps: 1) Establishing a frequency dynamic model based on parameter information of a wind-solar energy storage power electronic interface power supply comprising a synchronous machine, a grid-connected converter and a grid-following converter in a new energy power system; 2) Combining a network topology structure of the power system and a power relation among nodes, and constructing a multi-machine system transfer function matrix capable of representing a mapping relation between input power disturbance and node frequency response based on the frequency dynamic model; 3) Selecting a system global or target node as an analysis object according to the evaluation requirement, and determining a corresponding dynamic transfer relationship; 4) Setting a target frequency interval, an