CN-121984089-A - Power unit combination optimization method and system based on wind power plant rapid frequency response

CN121984089ACN 121984089 ACN121984089 ACN 121984089ACN-121984089-A

Abstract

The invention belongs to the technical field of operation optimization of novel power systems, and particularly discloses a power unit combination optimization method and system based on wind power plant rapid frequency response; the method comprises the steps of establishing a system frequency response model considering wind power rapid frequency response characteristics, taking the difference between active step disturbance and wind power response power and wind power slope exit power as input of the system frequency response model to respectively obtain time domain expressions of a first frequency drop minimum point and a second frequency drop minimum point, constructing a unit combination optimization model comprising frequency change constraint on the premise of meeting system safety and stability operation constraint by taking the minimum operation cost as a target, carrying out equivalent processing on nonlinear constraint, and solving the unit combination optimization model to obtain an optimal power unit combination operation strategy. The invention can fully exert the rapid response performance of wind power, and fully exert the adjustable capability of wind power when being cooperated with a synchronous machine to regulate frequency.

Inventors

DING LEI
YANG WENHUI
ZHAO GUIFANG
ZHANG CHENHUI
BAO WEIYU

Assignees

山东大学

Dates

Publication Date: 20260505
Application Date: 20260401

Claims (10)

1. The utility model provides a power unit combination optimization method based on wind power plant fast frequency response which is characterized in that the method comprises the following steps: Based on an optimized power curve of the wind power plant participating in the rapid frequency response under the maximum power point tracking operation and the load shedding operation, establishing a system frequency response model considering the rapid frequency response characteristic of wind power; Taking the difference between the active step disturbance and wind power response power and the wind power slope exit power as the input of a system frequency response model to respectively obtain a time domain expression of the lowest point of the first frequency drop and the lowest point of the second frequency drop; On the premise of meeting the safe and stable operation constraint of the system, the minimum operation cost is taken as a target, and a unit combination optimization model containing frequency change constraint is constructed; And carrying out equivalent processing on nonlinear constraint by adopting a piecewise linearization method, and solving the unit combination optimization model to obtain an optimal power unit combination operation strategy.
2. The power unit combination optimization method based on wind power plant rapid frequency response as claimed in claim 1, wherein the difference between active step disturbance and wind power response power is used as the input of a system frequency response model to obtain a time domain expression of the lowest point of the first frequency drop The method comprises the following steps: ; Wherein, the The frequency primary drop minimum point deviation R, K m is the equivalent droop coefficient and the mechanical power gain coefficient of the prime motor and the speed regulator parameters of the synchronous machine respectively, D is the equivalent damping coefficient of the power grid, omega r is the damped oscillation frequency, ζ is the damping ratio, omega n is the natural frequency, Time at the lowest frequency point; Is the phase angle; Is the disturbance power; Is a coefficient; For the response power of the blower in the MPPT state, And the response power of wind power in the load shedding standby state is obtained.
3. The method for optimizing the power unit combination based on the rapid frequency response of the wind power plant according to claim 1, wherein the wind power slope exit power is used as the input of a system frequency response model to obtain a time domain expression of the lowest point of the second frequency drop, specifically: ; ; Wherein, the Quasi-steady state frequency for first frequency dip; the wind power is withdrawn; for the frequency minimum time at equivalent load input, For the time when the first frequency dip reaches quasi-steady state, For the second drop in frequency nadir deviation, Inputting a frequency deviation value at a time t 0 under the equivalent load; The coefficient is R, K m , namely an equivalent droop coefficient and a mechanical power gain coefficient of parameters of a prime motor and a speed regulator of the synchronous machine, D is an equivalent damping coefficient of a power grid, omega r is a damped oscillation frequency, zeta is a damping ratio, and omega n is a natural frequency.
4. The method for optimizing power unit combinations based on rapid frequency response of a wind farm according to claim 1, wherein the unit combination optimization model aims at minimizing the sum of the power generation cost, start-stop cost, standby cost and wind farm standby cost of the thermal power unit.
5. A method of power pack optimization based on fast frequency response of a wind farm as claimed in claim 1, wherein the frequency variation constraint comprises: frequency one-time dip nadir constraint: ; frequency secondary dip nadir constraint: ; Wherein f min is the minimum system frequency point safety threshold; 、 The frequency primary drop minimum point deviation and the frequency secondary drop minimum point deviation are respectively; 、、 The frequency primary drop minimum, the frequency secondary drop minimum and the system rated frequency are respectively represented.
6. The method for optimizing the power unit combination based on the rapid frequency response of the wind power plant according to claim 1, wherein the method for equivalently processing the frequency primary drop minimum constraint or the frequency secondary drop minimum constraint by adopting a piecewise linearization method is specifically as follows: polymerizing parameters of the thermal power generating unit; Dividing a parameter space of the thermal power unit into N J series subspaces by adopting a piecewise linearization method; In each subspace S j , a hyperplane of the time domain expression closest to the lowest point of the first or second frequency drop in each subspace is found through an optimization model; And selecting a proper linear segment for each sampling point, so that the linear segment value at the sampling point is closest to the actual curve value, and thus obtaining a linearization expression of the frequency primary drop minimum point constraint or the frequency secondary drop minimum point constraint.
7. The method for optimizing the power unit combination based on the rapid frequency response of the wind power plant as claimed in claim 1, wherein the linearization processing is performed on the wind power load shedding rate in the output power constraint of the wind power plant, specifically: Discretizing the wind power load reduction rate value range D j,t into N L points , ,..., ,..., Simultaneously adding N L auxiliary binary variables as segment selection indicating variables , ,..., ,..., And N L auxiliary continuous variables , ,... , ... ;n=1, 2,...,N L ; Introducing a set of linear constraints satisfies: When (when) When the number of the codes is =1, =σ w When (when) When the value of the sum is =0, =0; There can be only one binary variable =1, Then The value of (2) is the selected nth wind power down load rate 。
8. An electric power unit combination optimizing system based on wind power plant fast frequency response, which is characterized by comprising: The frequency response model construction module is used for building a system frequency response model considering wind power rapid frequency response characteristics based on an optimized power curve of the wind power plant participating in rapid frequency response under the maximum power point tracking operation and the load shedding operation; The frequency response module is used for taking the difference between the active step disturbance and wind power response power and the wind power slope exit power as the input of a system frequency response model to respectively obtain time domain expressions of the lowest point of the first frequency drop and the lowest point of the second frequency drop; The unit optimization model construction module is used for constructing a unit combination optimization model containing frequency change constraint on the premise of meeting the system safety and stability operation constraint and taking the minimum operation cost as a target; And the model solving module is used for carrying out equivalent processing on nonlinear constraint by adopting a piecewise linearization method and solving the unit combination optimizing model to obtain an optimal power unit combination operation strategy.
9. A terminal device comprising a processor for implementing instructions and a memory for storing a plurality of instructions, characterized in that the instructions are adapted to be loaded by the processor and to perform the method for optimizing a power pack combination based on a fast frequency response of a wind farm according to any of claims 1-7.
10. A computer readable storage medium, in which a plurality of instructions are stored, characterized in that the instructions are adapted to be loaded by a processor of a terminal device and to perform the method for optimizing a power pack combination based on a fast frequency response of a wind farm according to any of claims 1-7.

Description

Power unit combination optimization method and system based on wind power plant rapid frequency response Technical Field The invention relates to the technical field of operation optimization of novel power systems, in particular to a power unit combination optimization method and system based on wind power plant rapid frequency response. Background The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. In the development process of a novel power system, in order to cope with the intermittent and fluctuation characteristics of new energy, a synchronous machine mainly based on coal electricity still needs to bear the important tasks of supporting the flexibility and the generating capacity of the power system. Under the background, as the permeability of new energy continuously rises, the active support provided by the synchronous machine alone is difficult to meet the requirement of safe operation of the system, and a new challenge is brought to the frequency stability and reliability of the power system, so that the new energy and the synchronous machine are used as main power sources together and participate in the active frequency support cooperatively, and the new energy and the synchronous machine become the necessary trend of the development of the novel power system. However, the wind-light fluctuation causes the running mode of the new energy to change, the new energy can realize various frequency modulation control strategies under different running modes, and the difference between the wind-light fluctuation and the control strategy can jointly influence the frequency modulation energy of the new energy, so that the available supporting capacity of the new energy is changed. Most of the conventional unit combination researches consider comprehensive inertia control under a wind power load shedding standby mode, neglect wind power frequency modulation capability under a wind power maximum power point tracking (Maximum Power Point Tracking, MPPT) running state, and further cannot realize efficient utilization of wind power frequency modulation energy, so that the running economy of a power system is to be further improved. Disclosure of Invention In order to solve the problems, the invention provides a power unit combination optimization method and a system based on wind power plant rapid frequency response, and simultaneously considers two operation states of wind power in MPPT and load shedding standby, and provides a power system unit combination optimization strategy based on wind power plant rapid frequency response under the condition of considering frequency safety constraint, so that the frequency supporting capability of wind power is fully exerted, the cooperative frequency modulation of wind power and a synchronous machine is realized, and the operation cost of a power system is reduced. In some embodiments, the following technical scheme is adopted: A power unit combination optimization method based on wind power plant rapid frequency response comprises the following steps: Based on an optimized power curve of the wind power plant participating in the rapid frequency response under the maximum power point tracking operation and the load shedding operation, establishing a system frequency response model considering the rapid frequency response characteristic of wind power; Taking the difference between the active step disturbance and wind power response power and the wind power slope exit power as the input of a system frequency response model to respectively obtain a time domain expression of the lowest point of the first frequency drop and the lowest point of the second frequency drop; On the premise of meeting the safe and stable operation constraint of the system, the minimum operation cost is taken as a target, and a unit combination optimization model containing frequency change constraint is constructed; And carrying out equivalent processing on nonlinear constraint by adopting a piecewise linearization method, and solving the unit combination optimization model to obtain an optimal power unit combination operation strategy. As a further scheme, taking the difference between the active step disturbance and wind power response power as the input of a system frequency response model to obtain a time domain expression of the lowest point of the first frequency dropThe method comprises the following steps: ; Wherein R, K m is equivalent droop coefficient and mechanical power gain coefficient of prime mover and speed regulator parameters of synchronous machine respectively, D is equivalent damping coefficient of power grid, omega r is damped oscillation frequency, ζ is damping ratio, omega n is natural frequency, Time at the lowest frequency point; Is the phase angle; Is the disturbance power; Is a coefficient; For the response power of the blower in the MPPT state, And the response power of