CN-121984143-A - Distributed photovoltaic polymerization frequency modulation standby optimal configuration method considering node frequency safety constraint under transmission and distribution cooperation

CN121984143ACN 121984143 ACN121984143 ACN 121984143ACN-121984143-A

Abstract

The invention discloses a distributed photovoltaic polymerization frequency modulation standby optimal configuration method considering node frequency safety constraint under transmission and distribution coordination. The method comprises the steps of describing uncertainty of frequency modulation capability of photovoltaic polymerization by using a Gaussian mixture model, establishing a power transmission network node frequency response model with frequency space distribution characteristics, establishing an optimal configuration model by combining opportunistic constraint planning with the aim of minimizing system power generation and frequency modulation standby cost, approximating frequency dynamics by using a Bernstein polynomial based on a frequency divider theory reduced response model and converting a differential algebra equation into an algebraic equation, converting the model into a mixed integer linear programming model by using binary expansion and Gaussian mixture model linear invariance, combining the Bernstein polynomial convex hull property tightening constraint, and finally solving the model to obtain optimal photovoltaic polymerization frequency modulation standby capacity and control parameters. The method accurately characterizes frequency space distribution, solves the problem of insufficient frequency safety risk identification, and improves the frequency safety level of the power system.

Inventors

Qin Hongpei
QIAN WEIJIE
Wan can
LIU HUI
WANG YUPENG
ZHAO BO
CHEN XIAOGANG
SUN ZHIPENG
HE ZHIQIANG
HUANG YUHANG

Assignees

浙江大学
国网浙江省电力有限公司嘉兴供电公司

Dates

Publication Date: 20260505
Application Date: 20260408

Claims (10)

1. The distributed photovoltaic polymerization frequency modulation standby optimal configuration method taking node frequency security constraint into consideration under transmission and distribution cooperation is characterized by comprising the following steps of: 1) Describing uncertainty of the frequency modulation capability of the large-scale distributed photovoltaic polymerization in the power distribution network by adopting a Gaussian mixture model, and establishing a transmission network node frequency response model taking frequency space distribution characteristics and the supporting effect of the distributed photovoltaic polymerization frequency into consideration; 2) Taking uncertainty of the distributed photovoltaic polymerization frequency modulation reserve capacity into consideration, and constructing a distributed photovoltaic polymerization frequency modulation reserve optimal configuration model of node frequency safety constraint by combining opportunistic constraint planning with the aim of minimizing power system power generation cost and frequency modulation reserve cost; 3) Reducing a power transmission network node frequency response model based on a frequency divider theory, dynamically approximating the frequency of each node of the power transmission network by using a Bernstein polynomial, and converting a differential algebraic equation of the power transmission network node frequency response model into an algebraic equation by combining the calculus operation property of the Bernstein polynomial; 4) Based on the algebraic equation obtained in the step 3), converting the distributed photovoltaic polymerization frequency modulation standby optimal configuration model containing bilinear terms and node frequency safety constraint of opportunity constraint into a mixed integer linear programming model by utilizing binary expansion and Gaussian mixture model linear invariance, and realizing constraint compaction by combining with the properties of a Bernstein polynomial convex hull; 5) And solving the mixed integer linear programming model, so as to obtain the optimal distributed photovoltaic polymerization frequency modulation spare capacity and control parameter configuration result.
2. The distributed photovoltaic polymerization frequency modulation standby optimal configuration method considering node frequency safety constraint under transmission and distribution coordination according to claim 1, wherein in step 1), when uncertainty of large-scale distributed photovoltaic polymerization frequency modulation capacity of a power distribution network is described by using a Gaussian mixture model, probability distribution of upward or downward frequency modulation capacity is represented by weighted combination of a plurality of Gaussian components, and each Gaussian component has a corresponding weight coefficient, mean value and variance.
3. The distributed photovoltaic polymerization frequency modulation standby optimal configuration method considering node frequency safety constraint under transmission and distribution cooperation is characterized in that in the step 1), when a transmission network node frequency response model is established, virtual nodes are respectively arranged for each synchronous generator and each power distribution network in a power system, the virtual nodes and the transmission network nodes form a system node together, the line impedance from the virtual nodes to the transmission network nodes corresponds to the internal transient reactance of the synchronous generator or the equivalent impedance of the power distribution network, and a system augmented admittance matrix is formed according to the line impedance, wherein the transmission network node frequency response model comprises a synchronous generator rotor motion equation, a speed regulator model, a turbine reheating process model, a transmission network tide equation and a distributed photovoltaic polymerization primary frequency modulation model in the power distribution network, wherein dynamic characteristics of a plurality of distributed photovoltaic in the power distribution network are equivalent to one section of inertia links, the equivalent inertia time constant is obtained through parameter identification, and the distributed photovoltaic polymerization primary frequency modulation model in the power distribution network reflects the dynamic relation between frequency deviation and frequency modulation power response.
4. The distributed photovoltaic polymerization frequency modulation standby optimal configuration method considering node frequency safety constraint under transmission and distribution coordination according to claim 3 is characterized in that an optimal configuration model constructed in the step 2) aims at minimizing system power generation cost and frequency modulation standby cost, constraint conditions comprise synchronous generator operation constraint, system power balance constraint before disturbance, transmission power upper limit constraint of transmission network line tide transmission power, node frequency safety constraint and distributed photovoltaic polymerization frequency modulation standby opportunity constraint, wherein the node frequency safety constraint requires that the frequency change rate of each node is not more than a maximum allowable value, quasi-steady state frequency deviation is not more than a set threshold value, frequency minimum point deviation is not more than a maximum allowable deviation, and the probability that the distributed photovoltaic polymerization frequency modulation standby opportunity constraint requires that the polymerization frequency modulation standby capacity provided by a power distribution network meets minimum requirements is not lower than a set confidence level.
5. The distributed photovoltaic polymerization frequency modulation standby optimal configuration method considering node frequency safety constraint under transmission and distribution cooperation according to claim 4 is characterized in that in the step 3), when a power transmission network node frequency response model is reduced based on a frequency divider theory, the network wave propagation speed is assumed to be far faster than the electromechanical transient state of a synchronous generator after system power disturbance, an augmented admittance matrix with simplified conductivity influence is ignored, and then an approximate relationship between the power transmission network node frequency and the virtual node power generation equipment frequency is established by combining the assumption that the voltage of each node of the power transmission network and the electric potential in power generation equipment are constant to rated values and combining the frequency divider theory.
6. The distributed photovoltaic polymerization frequency modulation standby optimal configuration method considering node frequency safety constraint under transmission and distribution coordination according to claim 5, wherein the specific process of dynamically approximating each node frequency of a power transmission network by using a Bernstein polynomial and converting a differential algebraic equation in step 3) is as follows: on the basis of reducing the frequency response model of the power transmission network node by the frequency divider theory, carrying out frequency dynamic approximation and differential algebra equation conversion operation; When the virtual node frequency of the synchronous generator and the power distribution network is solved, firstly, calculating the electromagnetic power change injected by each virtual node by adopting a direct current flow model so as to reflect the power interaction among power generation equipment in the system, and then, assuming that the injected current of each non-generator node in the transient process is kept unchanged, constructing a power transmission network node frequency response model completely comprising the dynamic state of each power generation equipment and a network equation; dividing a frequency dynamic simulation time domain into a plurality of time periods, and performing approximate characterization on virtual node voltage phase angles, frequency, node electromagnetic power injection, synchronous generator mechanical power, speed regulator output power regulation instructions and distribution network aggregate power responses in each time period by adopting a Bernstant polynomial with a specified order; Based on the differential and integral operation properties of the Bernstein polynomial, a differential algebraic equation describing the frequency dynamics of the system in the transmission network node frequency response model is re-parameterized into a Bernstein coefficient, nonlinear frequency dynamics is projected to a Bernstein polynomial basis space, and finally, complex nonlinear constraint containing the differential is converted into a linear algebraic equation only related to the Bernstein coefficient, so that the conversion from the original differential algebraic equation to the algebraic equation is completed, and the algebraic equation of the transmission network node frequency response model is obtained.
7. The distributed photovoltaic polymerization frequency modulation standby optimal configuration method considering node frequency safety constraint under transmission and distribution cooperation according to claim 6 is characterized in that in algebraic equations of a transmission network node frequency response model, bilinear terms exist in equations corresponding to a distribution network distributed photovoltaic polymerization primary frequency modulation process, so that the model is non-convex and nonlinear, a distributed photovoltaic polymerization primary frequency modulation coefficient is divided into a plurality of gears, a binary indicating variable is introduced for each gear, the frequency modulation coefficient is expressed as a weighted sum of a basic value and each gear increment through a binary unfolding technology, and linearization processing is carried out on the bilinear terms by combining a large M method, so that nonlinearity of the model is eliminated; Aiming at the opportunity constraint of distributed photovoltaic polymerization frequency modulation reserve in an algebraic equation of a transmission network node frequency response model, describing probability distribution characteristics of distributed photovoltaic polymerization frequency modulation reserve capacity through a Gaussian mixture model, converting the probability constraint which originally requires the polymerization frequency modulation reserve capacity provided by a power distribution network to meet the minimum requirement into a deterministic constraint based on a specific quantile of the random variable, and finally forming a complete mixed integer linear programming model, wherein the quantile is obtained through Newton iterative calculation.
8. The distributed photovoltaic polymerization frequency modulation standby optimization configuration method considering node frequency safety constraint under transmission and distribution coordination according to claim 7 is characterized in that in the step 4), when constraint compaction is achieved by combining with the convex hull property of a Bernstein polynomial, the maximum frequency modulation power provided by distributed photovoltaic polymerization in a power distribution network is considered to be the minimum frequency modulation standby of the power distribution network required for maintaining system node frequency safety, the minimum frequency modulation standby of the power distribution network required for maintaining system node frequency safety is combined, the convex hull property of the Bernstein polynomial is utilized to quantize the minimum polymerization frequency modulation standby constraint of distributed photovoltaic, interpolation optimization is conducted on the quantized minimum polymerization frequency modulation standby constraint of distributed photovoltaic by introducing an enhancement matrix based on a De Casteljau algorithm, so that a tighter constraint condition is obtained, and conservation of the constraint is reduced.
9. The distributed photovoltaic polymerization frequency modulation standby optimal configuration method considering node frequency safety constraint under transmission and distribution coordination according to claim 8, wherein in step 5), the mixed integer linear programming model is solved, so that an optimal distributed photovoltaic polymerization frequency modulation standby capacity and control parameter configuration result is obtained, and the specific process is as follows: Setting power transmission network topology and line parameters, synchronizing generator set capacity, inertia time constant and primary frequency modulation control parameters, and distributed photovoltaic equivalent time constant and aggregate frequency modulation capacity probability distribution parameters in a power distribution network, configuring frequency dynamic simulation time domain segmentation numbers, segmentation time lengths and Bernstant polynomial orders, and solving by a solver in combination with the established mixed integer linear programming model to obtain optimal distributed photovoltaic aggregate frequency modulation spare capacity and control parameter configuration results.
10. A computer readable storage medium having stored thereon computer instructions for causing a computer to perform the steps of the method according to any of claims 1-9.

Description

Distributed photovoltaic polymerization frequency modulation standby optimal configuration method considering node frequency safety constraint under transmission and distribution cooperation Technical Field The invention relates to a distributed photovoltaic polymerization frequency modulation standby optimal configuration method considering node frequency safety constraint under transmission and distribution coordination, and belongs to the field of operation control of an electric power system. Background The flexible resources such as large-scale new energy, energy storage and the like are accessed through the inverter/converter, so that the frequency safety problem of the power system is particularly complex and prominent. There is a need to update and expand the existing frequency control system, explore, discover and utilize the frequency modulation capability of multi-type flexible resources in a multi-dimensional manner, and improve the frequency stability of the system in an all-around manner. The proportion of the distributed photovoltaic in the power supply of the power system continuously rises, and the distributed photovoltaic has the characteristics of flexible control, high response speed and the like, and can be regarded as a high-quality frequency modulation resource. However, existing distributed photovoltaic participation in power system frequency modulation faces dual constraints of economy and reliability. On one hand, the distributed photovoltaic provides a reserved power space for up-regulation standby, and the conventional method lacks reasonable evaluation of cost of the light discarding machine, so that power generation income is damaged and energy is wasted. On the other hand, the photovoltaic output has strong randomness, the frequency supporting capability is not reliable as the synchronous machine, if the spare capacity is improperly configured, the system can face the problems of frequency modulation resource shortage, insufficient frequency modulation capability, frequency dynamic deterioration and the like, and even frequency safety accidents are caused in serious cases. For this reason, careful configuration of the distributed photovoltaic frequency modulation backup capacity and control parameters is required. The spare capacity of the system frequency modulation is generally configured by solving the unit combination of frequency safety constraint or economic dispatch optimization problem. Existing system frequency modulation reserve quantization typically relies on an inertial center frequency response model. The model assumes uniform frequency of the whole network, ignores the network topology structure, cannot reflect the power exchange and the spatial distribution difference of the frequency among nodes in the system, and easily causes over conservation or distortion of frequency security situation assessment. Therefore, the traditional method based on the assumption of the inertia center is difficult to realize accurate quantification of the distributed photovoltaic frequency modulation reserve and fine optimization of control parameters, so that the control scheme is poor in economical efficiency and cannot effectively cope with the frequency out-of-limit risk of the local node. Disclosure of Invention Aiming at the limitations of the related background technology, the invention provides a distributed photovoltaic polymerization frequency modulation standby optimal configuration method considering node frequency safety constraint under transmission and distribution coordination, which displays the spatial distribution characteristic of the characterization frequency, the frequency security risk of each node of the system is accurately estimated, uncertainty of the distributed photovoltaic frequency modulation capability is considered, and frequency security and operation economy of the system can be considered when the distributed photovoltaic participates in frequency modulation. The invention overcomes the unified assumption of the whole network frequency, considers the influence of the network topology on the frequency propagation, and prevents the local frequency out-of-limit risk. The system frequency dynamic including the high-order differential equation is converted into algebraic constraint through mathematical transformation, so that the model solving efficiency and engineering applicability are improved. In order to achieve the above purpose, the present invention adopts the following technical scheme: a distributed photovoltaic polymerization frequency modulation standby optimal configuration method considering node frequency safety constraint under transmission and distribution cooperation comprises the following steps: 1) Describing uncertainty of the frequency modulation capability of the large-scale distributed photovoltaic polymerization in the power distribution network by adopting a Gaussian mixture model, and establishing a transmission network no