CN-121983988-A - Method and device for constructing broadband oscillation stable domain of renewable energy grid-connected system parameter

CN121983988ACN 121983988 ACN121983988 ACN 121983988ACN-121983988-A

Abstract

The invention provides a method and a device for constructing a broadband oscillation stable domain of a renewable energy grid-connected system parameter, and belongs to the field of modeling and control of new energy grid-connected systems. The method comprises the steps of solving a basic stability domain of system parameters based on a return rate matrix of a sequence impedance model of a renewable energy grid-connected system, solving an optimal similarity transformation matrix for expanding the basic stability domain, constructing stability domain constraint conditions of the system parameters based on the optimal similarity transformation matrix and combining with a preset stability margin, and solving to obtain a final stability domain of the system parameters meeting the stability margin. The invention does not depend on point-by-point calculation, has high calculation efficiency, and can ensure that the requirement of the preset stability margin is met.

Inventors

WANG KAI
ZHANG YONGXIN
WANG YINSONG
TIAN XIAOMIN
LI PENGHUA
LI ZHENGXI
AN NA
YANG JIAN
ZHOU WANPENG
LIU TINGXIANG
CAO ZHIMEI
XIANG LIANGHAO
WANG ZIMING

Assignees

国网青海省电力公司经济技术研究院
国网青海省电力公司
华北电力大学（保定）

Dates

Publication Date: 20260505
Application Date: 20251222

Claims (10)

1. A method for constructing a broadband oscillation stable domain of a renewable energy grid-connected system parameter is characterized by comprising the following steps: solving a basic stability domain of the system parameters based on a return rate matrix of a sequential impedance model of the renewable energy grid-connected system; Solving an optimal similarity transformation matrix for expanding the basic stability domain; Based on the optimal similarity transformation matrix, combining a preset stability margin, constructing a stability domain constraint condition of the system parameter and solving to obtain a final stability domain of the system parameter meeting the stability margin.
2. The method of claim 1, wherein said solving a basic stability domain of said system parameter comprises: 1) Constructing a return rate matrix of a sequence impedance model of the renewable energy grid-connected system, wherein the return rate matrix is shown in a formula (1): Wherein H(s) represents a return rate matrix of the system, Y oc (s) represents an output admittance matrix of the system, Z g (s) represents an equivalent impedance matrix at the power grid side, and H pp (s)、H pn (s)、H np (s) and H nn (s) are elements of pp, pn, np and nn channels of the return rate matrix respectively; 2) According to the combination of the generalized Nyquist criterion and the Gal disc theorem, the following constraints are obtained: Wherein Re (a) represents the real part of a, ω represents angular frequency, j represents imaginary units, s=jω; Solving the formula (2) to obtain a basic stable domain of the system parameters.
3. The method of claim 2, wherein said solving an optimal similarity transformation matrix for expanding the basic stability domain comprises: Let Λ 1 ＝diag(α 1 ,α 2 ) and Λ 2 ＝diag(α 3 ,α 4 be present, where α 1 、α 2 、α 3 and α 4 are positive real numbers; Randomly selecting a group of parameter combinations at the boundary of a basic stability domain, wherein the parameters of the combination comprise m 1 ,m 2 ,…,m N ,ω,m i representing the ith parameter participating in the construction of the stability domain, i=1, 2,., N, substituting the parameter combinations into the formula (1) to obtain a parameter-containing rate matrix H (m 1 ,m 2 ,…,m N , omega); The objective of the optimal similarity transformation is to maximize both the shortest distance d 1 from the whole circle of the guerre disc centered on H pp (m 1 ,m 2 ,…,m N , ω) to the straight line γ= -1 and the shortest distance d 2 from the whole circle of the guerre disc centered on H nn (m 1 ,m 2 ,…,m N , ω) to the straight line γ= -1: meanwhile, the return rate matrix after the optimal similarity transformation of the lambda 1 、Λ 2 cannot cross the stability boundary, namely the following formula is satisfied: Solving the formulas (3) - (5) by using an interior point method to obtain the optimal results of the lambda 1 ＝diag(α 1 ,α 2 ) and the lambda 2 ＝diag(α 3 ,α 4 , namely the optimal similarity transformation matrix.
4. A method according to claim 3, further comprising: let the preset stability margin be beta m1 , and the final constraint condition of the system stability domain after combining the optimal similarity transformation matrix is: solving the formula (6) to obtain a system parameter stability domain meeting a preset stability margin.
5. The utility model provides a renewable energy grid-connected system parameter broadband oscillation stable domain construction device which is characterized in that the device comprises: The basic stability domain construction module is used for solving the basic stability domain of the system parameters based on a return rate matrix of a sequence impedance model of the renewable energy grid-connected system; the optimal similarity transformation matrix solving module is used for solving an optimal similarity transformation matrix for expanding the basic stability domain; The final stable domain solving module is used for constructing the stable domain constraint condition of the system parameter based on the optimal similarity transformation matrix and combining with a preset stability margin, and solving the constraint condition to obtain the final stable domain of the system parameter meeting the stability margin.
6. The apparatus of claim 5, wherein said solving for a substantially stable domain of said system parameter comprises: 1) Constructing a return rate matrix of a sequence impedance model of the renewable energy grid-connected system, wherein the return rate matrix is shown in a formula (1): Wherein H(s) represents a return rate matrix of the system, Y oc (s) represents an output admittance matrix of the system, Z g (s) represents an equivalent impedance matrix at the power grid side, and H pp (s)、H pn (s)、H np (s) and H nn (s) are elements of pp, pn, np and nn channels of the return rate matrix respectively; 2) According to the combination of the generalized Nyquist criterion and the Gal disc theorem, the following constraints are obtained: Wherein Re (a) represents the real part of a, ω represents angular frequency, j represents imaginary units, s=jω; Solving the formula (2) to obtain a basic stable domain of the system parameters.
7. The apparatus of claim 6, wherein the solving for the optimal similarity transformation matrix for expanding the basic stability domain comprises: Let Λ 1 ＝diag(α 1 ,α 2 ) and Λ 2 ＝diag(α 3 ,α 4 be present, where α 1 、α 2 、α 3 and α 4 are positive real numbers; Randomly selecting a group of parameter combinations at the boundary of a basic stability domain, wherein the parameters of the combination comprise m 1 ,m 2 ,…,m N ,ω,m i representing the ith parameter participating in the construction of the stability domain, i=1, 2,., N, substituting the parameter combinations into the formula (1) to obtain a parameter-containing rate matrix H (m 1 ,m 2 ,…,m N , omega); The objective of the optimal similarity transformation is to maximize both the shortest distance d 1 from the whole circle of the guerre disc centered on H pp (m 1 ,m 2 ,…,m N , ω) to the straight line γ= -1 and the shortest distance d 2 from the whole circle of the guerre disc centered on H nn (m 1 ,m 2 ,…,m N , ω) to the straight line γ= -1: meanwhile, the return rate matrix after the optimal similarity transformation of the lambda 1 、Λ 2 cannot cross the stability boundary, namely the following formula is satisfied: Solving the formulas (3) - (5) by using an interior point method to obtain the optimal results of the lambda 1 ＝diag(α 1 ,α 2 ) and the lambda 2 ＝diag(α 3 ,α 4 , namely the optimal similarity transformation matrix.
8. The apparatus as recited in claim 7, further comprising: let the preset stability margin be beta m1 , and the final constraint condition of the system stability domain after combining the optimal similarity transformation matrix is: solving the formula (6) to obtain a system parameter stability domain meeting a preset stability margin.
9. An electronic device, comprising: And a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being arranged to perform the method of any of the preceding claims 1-4.
10. A computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, the computer instructions for causing the computer to perform the method of any one of claims 1-4.

Description

Method and device for constructing broadband oscillation stable domain of renewable energy grid-connected system parameter Technical Field The invention belongs to the field of modeling and control of a new energy grid-connected system, and particularly relates to a method and a device for constructing a broadband oscillation stable domain of a renewable energy grid-connected system parameter. Background The renewable energy grid-connected system is a core framework for realizing electric energy transmission and absorption by connecting clean power generation units such as solar energy, wind energy and the like into a traditional power grid through a power electronic device, and is a key support for promoting clean transformation of an energy structure. However, due to the intermittence and volatility of the renewable energy source output and the low inertia and weak damping characteristics of the power electronic equipment, the system is easy to generate broadband oscillation, meanwhile, the oscillation risk is further aggravated by the time-varying of the system operation parameters, and the traditional single-point stability analysis method is difficult to cover a broadband range and parameter variation scenes in a whole. Therefore, the system parameter broadband oscillation stability domain is constructed, the parameter safety boundary is defined, and the system parameter broadband oscillation stability domain becomes a core technical requirement for guaranteeing large-scale high-proportion grid connection of renewable energy sources and improving the stable operation level of a power grid, and has important significance. In order to meet the requirements of online evaluation and real-time adjustment of related control parameters of a renewable energy grid-connected system, it is necessary to establish a broadband oscillation stability domain as a reference value of a maximum adjustment range of parameters. Currently, two main methods for constructing the broadband oscillation stability domain of the parameter are a point-by-point calculation method and a method for estimating based on a characteristic value range. The former needs to repeatedly solve and judge the system stability of the system state space model or the impedance model under specific operation conditions. The accuracy of the method is directly influenced by parameter area division and sampling intervals, large-scale intensive sampling is often required for obtaining reliable results, the efficiency is low, and the calculation requirement of a practical complex power system is difficult to meet. The method can quickly evaluate the distribution range of the system characteristic values instead of precisely calculating the specific characteristic values, so that the construction efficiency of the stable domain is improved, but the quick construction of the broadband oscillation stable domain at the present stage is not implemented in the field of the sequential impedance model, and the stability margin requirement in the actual system design is not specifically combined. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a method and a device for constructing a broadband oscillation stable domain of a renewable energy grid-connected system parameter. The method is applicable to the construction of the broadband oscillation stable domain of the sequential impedance model of the renewable energy grid-connected system, has high calculation efficiency, and can ensure that the requirement of a preset stability margin is met. The embodiment of the first aspect of the invention provides a method for constructing a broadband oscillation stable domain of a renewable energy grid-connected system parameter, which comprises the following steps: solving a basic stability domain of the system parameters based on a return rate matrix of a sequential impedance model of the renewable energy grid-connected system; Solving an optimal similarity transformation matrix for expanding the basic stability domain; Based on the optimal similarity transformation matrix, combining a preset stability margin, constructing a stability domain constraint condition of the system parameter and solving to obtain a final stability domain of the system parameter meeting the stability margin. In a specific embodiment of the present invention, the solving the basic stability domain of the system parameter includes: 1) Constructing a return rate matrix of a sequence impedance model of the renewable energy grid-connected system, wherein the return rate matrix is shown in a formula (1): Wherein H(s) represents a return rate matrix of the system, Y oc(s) represents an output admittance matrix of the system, Z g(s) represents an equivalent impedance matrix at the power grid side, and H pp(s)、Hpn(s)、Hnp(s) and H nn(s) are elements of pp, pn, np and nn channels of the return rate matrix respectively; 2) According to the combination of the ge