CN-122021421-A - Stability analysis method and system for pumped storage-wind power nonlinear coupling system

CN122021421ACN 122021421 ACN122021421 ACN 122021421ACN-122021421-A

Abstract

The invention relates to the technical field of transition process and control of a hydropower system, in particular to a stability analysis method and a stability analysis system of a pumped storage-wind power nonlinear coupling system, wherein the stability criterion is deduced based on Hopf bifurcation theory by establishing a nonlinear mathematical model covering a pumped storage power station, a wind power station and a power grid, a stability domain taking a speed regulator parameter as a coordinate is drawn, and after phase space track simulation verification, sensitivity analysis is carried out on key parameters based on the stability domain; the system comprises modeling, criterion derivation, stable domain drawing, verification and sensitivity analysis modules. The method and the system can accurately identify the stability boundary of the coupling system, define the parameter influence rule, provide support for system parameter optimization and accurate control, ensure the cooperative and stable operation of the system parameter optimization and the accurate control, and assist the renewable energy source to be connected in a large scale.

Inventors

Song Fanchao
SUN WEI
CHEN JIANHUA
XIONG YANLAI
YANG MINGDA
Zuo Tianlin
LIU TENGZE
BAN MEINA
WANG JING
LIU SHIJIA
CUI XIAO
LV DIANSHUAI
DU XIANJUN
YANG ZIQIANG
WANG JIALIN

Assignees

中国电建集团北京勘测设计研究院有限公司

Dates

Publication Date: 20260512
Application Date: 20260121

Claims (10)

1. The stability analysis method of the pumped storage-wind power nonlinear coupling system is characterized by comprising the following steps of: s1, establishing a nonlinear mathematical model capable of reflecting dynamic characteristics of a pumped storage-wind power nonlinear coupling system; S2, based on the Hopf bifurcation theory, obtaining a stability criterion of the coupling system by solving a system balance point, calculating a Jacobian matrix and a characteristic equation, setting bifurcation criterion and calculating a transversal coefficient; s3, selecting key parameters of the system to construct a parameter plane, and drawing a stable domain of the pumped storage-wind power nonlinear coupling system; s4, verifying the accuracy of the stability domain through theoretical prediction and phase space trajectory simulation comparison; s5, performing sensitivity analysis on the stability of the coupling system based on a stability domain to obtain an influence rule of the parameters on the stability of the coupling system.
2. The method for analyzing the stability of the pumped storage-wind power nonlinear coupling system according to claim 1, wherein in the step S1, the subsystem of the pumped storage power station comprises a water pump turbine, a diversion tunnel, a pressure regulating chamber, a pressure pipeline, a generator motor and a speed regulator; The subsystem of the wind power station comprises a permanent magnet synchronous motor, a pitch angle actuating mechanism, a wind turbine and a transmission device, wherein the power grid is represented by an equivalent generator which can reflect the load relation between a power generation end and a power utilization end.
3. The method for analyzing the stability of the pumped-storage-wind power nonlinear coupling system according to claim 2, wherein in step S1, the construction process of the nonlinear mathematical model includes: based on the moment characteristic and the flow characteristic of the water pump turbine, linearization processing is adopted to obtain a water pump turbine equation; neglecting a nonlinear term of head loss of the diversion tunnel, and establishing a diversion tunnel equation; Based on the law of conservation of mass, neglecting the influence of water flow inertia and head loss in a connecting pipe of the pressure regulating chamber, and establishing a pressure regulating chamber equation; establishing a pressure pipeline equation based on a nonlinear term of the head loss of the pressure pipeline; the PI control strategy is adopted, the influence of the time constant of the control guide vane servomotor is ignored, and a speed regulator equation is established; Aiming at the power generation working condition, a second-order nonlinear equation of the power generation motor is established; based on the Betz theory, establishing a wind turbine aerodynamic system model comprising a fan mechanical moment equation and a wind energy utilization coefficient calculation formula; adopting simple block rigid shaft assumption to establish a fan transmission system model; Based on the transient characteristics of the power grid, a power grid equation capable of reflecting the load and frequency characteristics is established.
4. The method for analyzing the stability of the pumped storage-wind power nonlinear coupling system according to claim 1, wherein in the step S2, the process of obtaining the stability criterion based on the Hopf bifurcation theory includes: The power equation of the coupling system is expressed as Wherein As bifurcation parameters, solving by a power equation to obtain balance points of the system; Computing Jacobian matrices at balance points And the characteristic equation of the Jacobian matrix The unfolding is as follows: Wherein, the As the coefficient of the characteristic equation, Is a Jacobian matrix eigenvalue; setting Hopf bifurcation criterion when there is When the characteristic equation is satisfied And the real part of the rest characteristic values is not 0, and the high-order term condition is satisfied at the same time, wherein Representing the real part of the eigenvalue λ; Calculating cross-sectional coefficients as Then determine that the system is in Where Hopf bifurcation occurs.
5. The method for analyzing stability of pumped-storage-wind power nonlinear coupling system according to claim 4, wherein in step S2, the process of obtaining a stability criterion further comprises system stability domain identification: According to cross-sectional coefficients If the bifurcation type is judged by positive and negative If it is determined that the supercritical Hopf branches, if Judging that the subcritical Hopf branches; And integrating the Hopf bifurcation occurrence condition, the cross-section coefficient judgment result and the bifurcation type judgment result to obtain the stability criterion of the coupling system.
6. The method for analyzing the stability of the pumped storage-wind power nonlinear coupling system according to claim 1, wherein in the step S3, the key parameters of the system are a proportional gain and an integral gain of a pumped storage power station speed regulator; The parameter plane takes proportional gain as an abscissa and integral gain as an ordinate, the integral gain is selected as a bifurcation parameter, corresponding bifurcation points are marked as a stable domain, an unstable domain and bifurcation lines are divided according to the stability criterion, and the stable domain is drawn.
7. The method for analyzing stability of pumped-storage wind power nonlinear coupling system according to claim 6, wherein in step S3, when a stable domain is drawn, a parameter region corresponding to an integral gain smaller than a proportional gain is determined as a stable domain, a parameter region corresponding to an integral gain larger than a proportional gain is determined as an unstable domain, and a curve corresponding to an integral gain equal to a proportional gain is determined as a bifurcation line based on supercritical Hopf bifurcation characteristics.
8. The method for analyzing stability of pumped-storage-wind power nonlinear coupling system according to claim 5, wherein in step S4, the process of confirming accuracy of the stability domain is specifically: Based on the bifurcation type obtained in the step S2, determining a theoretical prediction result that the system in the stable domain converges to a balance point, a limit ring appears in the system in the unstable domain, and the system on the bifurcation point forms a stable limit ring; three groups of speed regulator parameters are selected and are respectively positioned in a stable domain, a bifurcation point and an unstable domain; Selecting the rotational speed of a pumping speed unit, the flow of a pressure pipeline and the rotational speed of a wind turbine generator of the coupling system as core state variables, and drawing a phase space trajectory graph of the core state variables under three groups of parameters; and comparing the actual phase space track convergence condition with a theoretical prediction result, and if the actual phase space track convergence condition and the theoretical prediction result are consistent, confirming that the stable domain is accurate.
9. The method for analyzing the stability of the pumped storage-wind power nonlinear coupling system according to claim 1, wherein in the step S5, the selected key parameters include a water pump turbine inertia time constant, a grid equivalent unit inertia time constant, a wind turbine shaft system time constant and an initial wind speed; And (3) respectively adjusting the values of each group of parameters and repeating the steps S1-S3 to obtain stable domain and state variable dynamic response data under different parameter values so as to reveal the stability change rule of the system.
10. Stability analysis system of pumped storage-wind power nonlinear coupling system, characterized by including: the modeling module is used for establishing a nonlinear mathematical model capable of reflecting the dynamic characteristics of the pumped storage-wind power nonlinear coupling system; The criterion deriving module is connected with the modeling module and is used for obtaining the stability criterion of the coupling system based on the Hopf bifurcation theory by solving a system balance point, calculating a Jacobian matrix and a characteristic equation, setting bifurcation criterion and calculating a transversal coefficient; The stable domain drawing module is connected with the criterion deriving module and is used for selecting key parameters of the system to construct a parameter plane and drawing the stable domain of the pumped storage-wind power nonlinear coupling system; the verification module is connected with the stable domain drawing module and is used for verifying the accuracy of the stable domain through theoretical prediction and phase space track simulation comparison; The sensitivity analysis module is respectively connected with the modeling module, the criterion deduction module and the stability domain drawing module and is used for carrying out sensitivity analysis on the stability of the coupling system to obtain the influence rule of the parameters on the stability of the coupling system.

Description

Stability analysis method and system for pumped storage-wind power nonlinear coupling system Technical Field The invention belongs to the technical field of transition process and control of hydropower energy systems, and particularly relates to a stability analysis method and system of a pumped storage-wind power nonlinear coupling system. Background Under the trend of energy structure to clean low-carbon transformation, wind energy is an important form of renewable energy, and large-scale development and grid connection of the renewable energy form a key path of energy transformation. Wind energy has the output characteristics of randomness, intermittence and volatility, and the characteristic causes that the wind energy forms a significant technical challenge for safe and stable operation of a power system after grid connection. The pumped storage technology is used as a mature large-scale energy storage technology, has the technical advantages of large capacity, quick response, strong regulation capability and long service life, can effectively cope with the fluctuation of renewable energy sources, improves the flexibility and reliability of a power system, and is a key technical means for supporting the large-scale grid connection of new energy sources such as wind energy and the like. The pumped storage-wind power nonlinear coupling system belongs to a complex hydraulic-mechanical-electric coupling nonlinear system, the internal action mechanism of the system is not clear, the operation characteristics are not deeply explored, and the stable operation of the system is difficult to be effectively ensured. The stability research of the existing power system has obvious technical limitations that the research core focuses on single objects of a pumped storage power station or a wind power station, mainly analyzes stability influence factors and lifting strategies of a single system, and lacks special research on a pumped storage-wind power coupling system. For example, in the prior art, zou and the like establish a double-variable admittance model of a grid-connected system of a direct-drive permanent magnet synchronous generator wind power plant taking wind speed into consideration, only analyze the stability of an independent system of the wind power plant, zhang and the like establish a nonlinear model of a grid-connected hydropower station with a long connecting pipe voltage regulating well, and the stability and dynamic characteristics of the independent system of the hydropower station are analyzed by adopting the Hopf bifurcation theory, so that the coupling scene of pumped storage and wind power is not involved. In view of this, the present invention has been made. Disclosure of Invention In order to solve the technical problems in the prior art, the invention provides a stability analysis method and a system of a pumped storage-wind power nonlinear coupling system, which solve the problems that the action mechanism of the pumped storage-wind power nonlinear coupling system is unknown and the stable operation is difficult to ensure. In order to achieve the above purpose, the technical scheme of the invention is as follows: In a first aspect, a stability analysis method of a pumped storage-wind power nonlinear coupling system includes: s1, establishing a nonlinear mathematical model capable of reflecting dynamic characteristics of a pumped storage-wind power nonlinear coupling system; S2, based on the Hopf bifurcation theory, obtaining a stability criterion of the coupling system by solving a system balance point, calculating a Jacobian matrix and a characteristic equation, setting bifurcation criterion and calculating a transversal coefficient; s3, selecting key parameters of the system to construct a parameter plane, and drawing a stable domain of the pumped storage-wind power nonlinear coupling system; s4, verifying the accuracy of the stability domain through theoretical prediction and phase space trajectory simulation comparison; s5, performing sensitivity analysis on the stability of the coupling system to obtain an influence rule of the parameters on the stability of the coupling system. Further, in step S1, the subsystem of the pumped storage power station includes a water pump turbine, a diversion tunnel, a pressure regulating chamber, a pressure pipeline, a generator motor and a speed regulator; The subsystem of the wind power station comprises a permanent magnet synchronous motor, a pitch angle actuating mechanism, a wind turbine and a transmission device, wherein the power grid is represented by an equivalent generator which can reflect the load relation between a power generation end and a power utilization end. Further, in step S1, the construction process of the nonlinear mathematical model includes: based on the moment characteristic and the flow characteristic of the water pump turbine, linearization processing is adopted to obtain a water pump turbine equation; neglecting a nonli