CN-121981563-A - Power system security assessment method, device, equipment and medium

CN121981563ACN 121981563 ACN121981563 ACN 121981563ACN-121981563-A

Abstract

The application discloses a power system safety evaluation method, a device, equipment and a medium, which relate to the technical field of power system management and comprise the steps of constructing an initial explicit constraint set taking unit output as a decision variable, screening the initial explicit constraint set to obtain an effective domain boundary set, establishing a probability distribution model of uncertain power factors, extracting first probability characteristics of the uncertain power factors by using the probability distribution model, transmitting the uncertainty of each power grid node to a corresponding effective domain boundary based on the effective domain boundary set and the first probability characteristics to obtain second probability characteristics of each effective domain boundary, obtaining a probabilistic feasible domain boundary based on each second probability characteristic, and evaluating a power system according to the probabilistic feasible domain boundary. The probability evaluation of the safety risk of the power system with clear physical meaning is realized by transmitting the uncertainty of the source load from the power grid node to the effective boundary and calculating the probability density function of the source load.

Inventors

LI ZUYI
YAN LEI
ZHOU YILIN
CHEN YANQI
SHEN SHUYANG

Assignees

浙江大学

Dates

Publication Date: 20260505
Application Date: 20260409

Claims (10)

1. A power system security assessment method, comprising: acquiring operation parameters and constraint conditions of a target power system, and constructing an initial explicit constraint set taking unit output as a decision variable based on the operation parameters and the constraint conditions; Performing multistage screening on the initial explicit constraint set sequentially through coarse screening, power grid branch capacity screening and umbrella constraint identification to remove redundant constraints, so as to obtain an effective domain boundary set, wherein the effective domain boundary set is a boundary constraint set of an operation feasible domain forming the target power system; Establishing a probability distribution model of uncertainty power factors of a power system source side and a load side, and extracting first probability characteristics of each uncertainty power factor by using the probability distribution model; transmitting uncertainty of each grid node in the target power system to a corresponding effective domain boundary based on the effective domain boundary set and the first probability feature to acquire a second probability feature of each effective domain boundary; And calculating a corresponding probability density function based on each second probability feature to obtain a probability feasible domain boundary, and evaluating the safety of the target power system under the influence of source load uncertainty according to the probability feasible domain boundary.
2. The power system safety assessment method according to claim 1, wherein the constructing an initial explicit constraint set using unit output as a decision variable based on the operation parameter and the constraint condition comprises: According to the direct current power flow model corresponding to the target power system, network topology parameters in the operation parameters and generator output parameters, constructing a linearization constraint relation taking unit output as a decision variable; And constructing the initial explicit constraint set which takes the unit output as a decision variable and comprises the unit output constraint and the branch power flow constraint by utilizing the linearization constraint relation and the branch transmission capacity limit value in the constraint condition.
3. The power system security assessment method of claim 1, wherein the process of coarsening the initial set of explicit constraints comprises: setting the generator output with positive coefficient as the maximum value and the generator output with negative coefficient as the minimum value in each branch power flow constraint in the initial explicit constraint set so as to determine the maximum value corresponding to each branch power flow constraint; setting the generator output with positive coefficient in each branch power flow constraint as the minimum value and the generator output with negative coefficient as the maximum value so as to determine the minimum value corresponding to each branch power flow constraint; If the maximum value corresponding to any branch flow constraint is not greater than the corresponding preset branch flow upper limit and the minimum value corresponding to any branch flow constraint is not less than the corresponding preset branch flow lower limit, eliminating any branch flow to obtain a coarse-screened constraint set, wherein the preset branch flow upper limit and the preset branch flow lower limit are determined based on the physical transmission capacity of the branch.
4. A method of evaluating the safety of an electrical power system according to claim 3, wherein the process of screening the coarse screened constraint set for grid leg capacity comprises: respectively constructing a first linear optimization model taking the maximized branch tidal current value as a target and a second linear optimization model taking the minimized branch tidal current value as a target, wherein the solutions of the first linear optimization model and the second linear optimization model all need to meet the output force constraint and the load balance constraint of all units except the current branch tidal current constraint to be checked in the initial explicit constraint set; solving each branch flow constraint in the coarse-screened constraint set based on the first linear optimization model and the second linear optimization model to obtain a theoretical maximum value and a theoretical minimum value which are respectively corresponding to each branch flow constraint; And if the theoretical maximum value corresponding to any branch flow constraint is not greater than the corresponding preset branch flow upper limit and the theoretical minimum value corresponding to any branch flow constraint is not less than the corresponding preset branch flow lower limit, removing any branch flow from the coarse screening post-constraint set to obtain a secondary screening post-constraint set.
5. The power system security assessment method according to claim 4, wherein the process of umbrella constraint identification for the secondary filtered constraint set comprises: Constructing an umbrella constraint model aiming at maximizing the relaxation amount of branch power flow constraints, and solving each branch power flow constraint in the secondary screening constraint set by using the umbrella constraint model to obtain the maximum relaxation amount respectively corresponding to each branch power flow constraint, wherein the solving of the umbrella constraint model needs to meet all constraints except the current branch power flow constraint to be checked in the secondary screening constraint set; And if the maximum relaxation amount corresponding to any branch flow constraint is greater than zero, eliminating any branch flow constraint from the constraint set after secondary screening.
6. The power system security assessment method according to claim 1, wherein the extracting the first probability feature of each uncertainty power factor comprises: And obtaining each order of origin moment corresponding to probability distribution of wind power output fluctuation, photovoltaic output fluctuation and load fluctuation, calculating corresponding each order of semi-invariant based on each order of origin moment, and determining each order of semi-invariant as the first probability characteristic.
7. The power system security assessment method according to claim 1, wherein the calculating a respective probability density function based on each of the second probability features comprises: Constructing an information entropy maximization objective function according to the maximum entropy principle; And taking the second probability feature as a moment constraint condition of the objective function, solving a Lagrange multiplier corresponding to the moment constraint condition, and determining the probability density function of the probability feasible region boundary according to the Lagrange multiplier.
8. An electric power system safety evaluation device, characterized by comprising: The constraint set construction module is used for acquiring the operation parameters and constraint conditions of the target power system and constructing an initial explicit constraint set taking the unit output as a decision variable based on the operation parameters and the constraint conditions; The constraint eliminating module is used for carrying out multistage screening on the initial explicit constraint set through coarse screening, power grid branch capacity screening and umbrella constraint identification in sequence so as to eliminate redundant constraint and obtain an effective domain boundary set, wherein the effective domain boundary set is a boundary constraint set of an operation feasible domain of the target power system; The model construction module is used for establishing a probability distribution model of uncertainty power factors of a source side and a load side of the power system and extracting first probability characteristics of the uncertainty power factors by using the probability distribution model; The probability feature acquisition module is used for transmitting the uncertainty of each power grid node in the target power system to the corresponding effective domain boundary based on the effective domain boundary set and the first probability feature so as to acquire a second probability feature of each effective domain boundary; the safety evaluation module is used for calculating a corresponding probability density function based on each second probability feature so as to obtain a probability feasible domain boundary, and evaluating the safety of the target power system under the influence of source load uncertainty according to the probability feasible domain boundary.
9. An electronic device, comprising: A memory for storing a computer program; a processor for executing the computer program to implement the power system security assessment method according to any one of claims 1 to 7.
10. A computer readable storage medium for storing a computer program which, when executed by a processor, implements the power system security assessment method according to any one of claims 1 to 7.

Description

Power system security assessment method, device, equipment and medium Technical Field The present invention relates to the field of power system management technologies, and in particular, to a method, an apparatus, a device, and a medium for evaluating security of a power system. Background The duty cycle of new energy in electrical power systems is increasing year by year. The new energy is affected by factors such as natural environment, so that the new energy has stronger uncertainty and brings challenges to the stable operation of the power system. The feasibility and the safety of the power system are evaluated, and the system can be ensured to stably operate. In order to ensure the stable operation of the power system, the method for determining the feasible region (safety region) is currently applied to the fields of large electricity, power distribution networks, comprehensive energy systems and the like. In the existing research of the feasible region of the electric power system, a statistical method is mainly used, the feasible region boundary obtained by the method lacks a physical corresponding relation with system constraint, and the influence degree of source load uncertainty on the feasible region boundary cannot be quantified accurately by a physical interpretable method. Disclosure of Invention In view of the above, the present invention aims to provide a method, an apparatus, a device and a medium for evaluating safety of an electric power system, which can realize probabilistic evaluation of safety risk of the electric power system with clear physical meaning by transferring uncertainty of source load from a power grid node to an effective boundary and calculating a probability density function thereof. The specific scheme is as follows: in a first aspect, the present application provides a method for evaluating safety of an electric power system, including: acquiring operation parameters and constraint conditions of a target power system, and constructing an initial explicit constraint set taking unit output as a decision variable based on the operation parameters and the constraint conditions; Performing multistage screening on the initial explicit constraint set sequentially through coarse screening, power grid branch capacity screening and umbrella constraint identification to remove redundant constraints, so as to obtain an effective domain boundary set, wherein the effective domain boundary set is a boundary constraint set of an operation feasible domain forming the target power system; Establishing a probability distribution model of uncertainty power factors of a power system source side and a load side, and extracting first probability characteristics of each uncertainty power factor by using the probability distribution model; transmitting uncertainty of each grid node in the target power system to a corresponding effective domain boundary based on the effective domain boundary set and the first probability feature to acquire a second probability feature of each effective domain boundary; And calculating a corresponding probability density function based on each second probability feature to obtain a probability feasible domain boundary, and evaluating the safety of the target power system under the influence of source load uncertainty according to the probability feasible domain boundary. Optionally, the constructing an initial explicit constraint set with the unit output as a decision variable based on the operation parameter and the constraint condition includes: According to the direct current power flow model corresponding to the target power system, network topology parameters in the operation parameters and generator output parameters, constructing a linearization constraint relation taking unit output as a decision variable; And constructing the initial explicit constraint set which takes the unit output as a decision variable and comprises the unit output constraint and the branch power flow constraint by utilizing the linearization constraint relation and the branch transmission capacity limit value in the constraint condition. Optionally, the process of coarsely screening the initial explicit constraint set includes: setting the generator output with positive coefficient as the maximum value and the generator output with negative coefficient as the minimum value in each branch power flow constraint in the initial explicit constraint set so as to determine the maximum value corresponding to each branch power flow constraint; setting the generator output with positive coefficient in each branch power flow constraint as the minimum value and the generator output with negative coefficient as the maximum value so as to determine the minimum value corresponding to each branch power flow constraint; If the maximum value corresponding to any branch flow constraint is not greater than the corresponding preset branch flow upper limit and the minimum value corresponding to any