CN-116388207-B - STATCOM multi-target collaborative planning method for improving voltage stability

CN116388207BCN 116388207 BCN116388207 BCN 116388207BCN-116388207-B

Abstract

The invention discloses a STATCOM multi-target collaborative planning method for improving voltage stability, which comprises the steps of selecting a candidate busbar as an installation position of the STATCOM by adopting a sensitivity analysis method, generating a first generation data population by utilizing a second generation non-dominant sorting genetic algorithm based on the candidate busbar screen, including an initial capacity and a wind abandon proportion of a wind power plant, calculating a static voltage stability index of a system, simulating uncertainty of wind power output by utilizing TOAT sets, calculating a short-term voltage stability index under each TOAT corresponding to an accident, selecting an optimal pareto solution based on investment planning and operation cost, the static voltage stability index and the short-term voltage stability index under different wind power output conditions, updating the initial capacity and the wind abandon proportion in the previous generation data population, generating new generation data when iteration is not terminated, executing steps S3-S5, and solving an optimal scheme when iteration is terminated.

Inventors

SHEN YUMING
LUO YONGJIE
ZHU LIUZHU
WU XIAOMING
WANG XULI
ZHANG HUI
CHENG XIAO
XU RAN
Ling ru
XU XIAOLONG

Assignees

国网安徽省电力有限公司经济技术研究院

Dates

Publication Date: 20260505
Application Date: 20221024

Claims (8)

1. A STATCOM multi-objective collaborative planning method for improving voltage stability, the method comprising the steps of: s1, selecting a candidate bus as an installation position of a STATCOM by adopting a sensitivity analysis method; S2, generating a first generation data population by using a second generation non-dominant sorting genetic algorithm based on the candidate buses, wherein the control variables comprise the initialization capacity of a single STATCOM and the wind discarding proportion of a wind farm; S3, calculating a static voltage stability index of the wind power system, calculating an optimal power flow by taking the power generation cost of the generator as a target, and comparing the power generation cost of using the preventive control with the power generation cost of not using the preventive control; S4, simulating uncertainty of wind power output by utilizing TOAT sets, performing key expected accident simulation on the wind power system under the condition represented by each TOAT set in the TOAT set, and calculating a short-term voltage stability index under the condition of corresponding accidents of each TOAT; S5, selecting an optimal pareto solution based on investment planning and running cost, static voltage stability index and short-term voltage stability index under different wind power output conditions, and updating the initialization capacity of the single STATCOM in the previous generation data population and the wind abandoning proportion of a wind farm; S6, when iteration is not terminated, generating new generation data through mutation, recombination and crossing of the data, and then executing steps S3-S5; s7, when iteration is terminated, a pareto front composed of pareto solutions is obtained, the static voltage stability index or the short-term voltage stability index is selected as an optimization target, time domain simulation is carried out under a plurality of load conditions, and a solution with the minimum static voltage stability index or a solution with the minimum short-term voltage stability index is obtained as an optimal scheme; In the step S4, the calculation formula of the short-term voltage stability index under the accident corresponding to each TOAT is: wherein: And Respectively representing fault removal time and calculation end time; Representing the number of bus bars; TVDI at t time of the kth accident for the ith bus, wherein TVDI represents a transient voltage deviation index; And Respectively representing the static voltage amplitude of the bus i at the time t after the accident and before the accident; Is a threshold value; The said The formula of (2) is: wherein: Is a positive real number greater than 1; , , , respectively, four stages are represented by the two, , , , , Respectively representing time intervals; Indicating the moment of the resected fault.
2. The STATCOM multi-target collaborative planning method for improving voltage stability according to claim 1, wherein the step S1 of selecting a candidate bus as an installation position of the STATCOM by using a sensitivity analysis method includes: By adopting the sensitivity analysis method, the sensitivity of the static voltage stability index and the short-term voltage stability index of the wind power system to the STATCOM installation capacity of each bus is analyzed, and a plurality of buses with the maximum sensitivity are determined as candidate buses, wherein the formula is expressed as follows: wherein: The sensitivity of the static voltage stability index to the STATCOM installation capacity of each busbar is represented; The sensitivity of the static voltage stability index to the STATCOM installation capacity of each busbar is represented; indicating when the STATCOM is installed at capacity of The voltage collapse approaches the value corresponding to the index VCPI; indicating when the STATCOM is installed at capacity of The transient voltage deviates from the value corresponding to index TVSI; indicating when the STATCOM is installed at capacity of The voltage collapse approaches the value corresponding to the index VCPI; indicating when the STATCOM is installed at capacity of The transient voltage deviates from the value corresponding to index TVSI; Representing the installation capacity of STATCOM; the amount of change in STATCOM installation capacity is shown.
3. The STATCOM multi-target collaborative planning method for improving voltage stability according to claim 1 is characterized in that in the step S3, a calculation formula of a static voltage stability index of the wind power system is as follows: wherein: representing a voltage collapse near index (voltage collapse proximity indicator) of the first branch; representing the probability of occurrence of an accident K, K representing the set of accidents, and L representing the set of all branches.
4. A STATCOM multi-objective collaborative planning method for improving voltage stability according to claim 1 and including, prior to step S4: and using a field port orthogonal experiment, and using the upper bound and the lower bound of the output of a group of wind power plants to replace the uncertainty of the output of the wind power plants to obtain the TOAT data set.
5. A STATCOM multi-objective collaborative planning method for improving voltage stability according to claim 4, wherein in step S4, the uncertainty of wind power output is simulated by TOAT sets, and key expected accident simulation is performed on the wind power system under the condition represented by each TOAT in the TOAT sets, and short-term voltage stability index under each TOAT corresponding accident is calculated, including: Simulating uncertainty of wind power output by utilizing the TOAT sets, and performing key expected accident simulation on the wind power system under the condition that each TOAT in the TOAT sets represents; triggering emergency control when the voltage amplitude exceeds a threshold value and reaches a certain time, and judging whether the wind power system is dynamically stable after partial load is removed; If yes, calculating the short-term voltage stability index under the accident, and then simulating the next key expected accident until TOAT sets of the short-term voltage stability index are calculated; If not, the calculation is directly ended.
6. A STATCOM multi-objective collaborative planning method for improving voltage stability according to claim 1, wherein in step S5, the calculation formulas of the investment plan and the operation cost are: Wherein C represents the total cost; representing the investment cost of STATCOM; reduced costs after rescheduling for implementing power generation; the method is short-time wind curtailment cost for the wind farm.
7. The STATCOM multi-objective collaborative planning method for improving voltage stability according to claim 1, wherein the step S7, when iteration is terminated, obtains a pareto front composed of pareto solutions, selects the static voltage stability index or the short-term voltage stability index as an optimization objective, and performs time domain simulation under several load conditions to obtain a solution with the minimum investment planning and running cost or static voltage stability index or a solution with the minimum short-term voltage stability index as an optimal solution, includes: traversing each pareto solution in the pareto front, and selecting the investment planning and running cost or the static voltage stability index or the short-term voltage stability index as an optimization target; Performing time domain simulation under a plurality of load conditions to obtain the investment planning and running cost or the static voltage stability index or the short-term voltage stability index under each load condition; averaging the investment planning and operating costs or the static voltage stability index or the short-term voltage stability index under various load conditions; And selecting a solution with the smallest average value as an optimal solution based on the average value corresponding to each pareto solution.
8. A STATCOM multi-objective collaborative planning method for improving voltage stability according to claim 7, wherein in step S5, the investment planning and operation cost of the system, the static voltage stability index and the short-term voltage stability index are optimized by a second generation non-dominant ranking genetic algorithm as follows: wherein the first s.t. is a constraint condition of a static layer, , Active and reactive power for synchronous generator g; , For wind farms Active and reactive power emitted; , active and reactive power for the load; , For wind farms Active and reactive power of the wind curtailed; reactive power emitted for STATCOM; Is a bus bar Is set to the voltage amplitude of (1); , , Is a bus bar The real part and the imaginary part of admittance of the branch and the phase angle difference; , Is a bus bar Upper and lower limits of the voltage amplitude of (a); , The upper and lower limits of the power flow for branch l; , , , Is a synchronous generator Upper and lower limits of the active and reactive power of (a); For wind farms Is a waste wind capacity of (1); Is the wind abandoning rate; B represents a set of all nodes; Representing a set of all wind power plants; The second s.t. is a constraint condition of a transient state level, wherein the superscript shed and c in the formula respectively represent load shedding and wind abandoning; Respectively representing the power angles between any two generators; , , the time when the voltage is recovered to the allowable threshold, the fault clearing time and the maximum allowable time when the allowable voltage is recovered to the threshold after the fault clearing are respectively represented; , Respectively representing the thrown load capacity of the ith load busbar and the maximum throwing load capacity allowed by the corresponding busbar in the kth accident; For wind farms At the position of The voltage amplitude at the moment; , the threshold values of high voltage crossing and low voltage crossing of the wind farm are respectively; representing the active power generated by generator g when accident k occurs; representing the active power generated by the wind driven generator w when the accident k occurs; the reactive power generated by the generator g when the accident k occurs is represented; representing reactive power emitted by the wind farm w when an accident k occurs; representing reactive power emitted by the STATCOM at the time of an incident; representing the maximum allowable power angle difference between any two generators.

Description

STATCOM multi-target collaborative planning method for improving voltage stability Technical Field The invention relates to the technical field of improving voltage stability of a high-proportion wind power system, in particular to a STATCOM multi-target collaborative planning method for improving voltage stability. Background The dynamic reactive power compensation device can effectively improve the stability of short-term voltage, such as a static synchronous compensator (static synchronous compensator, STATCOM) which can respond in a few milliseconds, but whether the STATCOM can fully exert the performance depends on the capacity optimization configuration and the reasonable installation position. The inventor has proposed a multi-objective optimization model based on STATCOM installation location, and three indexes are proposed to evaluate the stability of static and short-term voltages, but the uncertainty of high permeability of wind power and fan output of the novel power system and the power characteristics after accidents are not considered. Due to the high permeability of wind power, the performance of the wind power generator in an accident state is critical to the overall stability of the system, and the power unbalance problem can be caused by cutting or reducing the power generation under the condition of no verification, and a cracking event can be possibly caused. For a power system containing a wind driven generator, reasonable configuration of a reactive power supply is important to improve the low/high voltage ride through (LVRT/HVRT) capability of the wind driven generator and to improve the voltage stability of the system. On the other hand, since the large power failure event is mostly caused by weather, adjusting the output of the wind driven generator according to the weather condition is also an effective means for improving the voltage stability of the system. However, current research considerations for STATCOM planning are not comprehensive, such as the lack of wind curtailment as a preventive control measure (PREVENTIVE CONTROL, PC) to improve system voltage stability, nor is the inherent uncertainty of wind power generation taken into account, nor is STATCOM taken as a schedulable unit, nor is it considered within the overall generator output regulation of the system. These simplifications and omissions will make the overall planning result conservative, resulting in a lower utilization of the reactive compensation equipment. Therefore, for low inertia systems with a large amount of induction motor load (more susceptible to voltage disturbances), a fast response reactive compensation device such as STATCOM is necessary but in extreme cases still insufficient to guarantee the stability of the power system during transient voltage events. The traditional single-stage planning method is difficult to solve the problem of efficient arrangement of reactive power, and a conservative planning decision is easy to cause. In view of the problems mentioned in the background art and the shortcomings of the prior art, the following problems are needed to be solved: 1) Short-time wind curtailment which can effectively improve the voltage stability of a high-proportion wind power system is not taken as a prevention control means, and uncertainty of the output of a fan is not taken into consideration. 2) STATCOM is not considered as a schedulable unit within the regulated generator output regulation. 3) Planning is limited to a single stage, and a plurality of stages are not considered cooperatively, so that a planning scheme is too conservative easily, and the efficient exertion of the reactive power supply effect is affected. Disclosure of Invention The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, an object of the present invention is to provide a STATCOM multi-objective collaborative planning method capable of effectively realizing optimization of voltage stability of a high-ratio wind power system. According to the embodiment of the invention, the STATCOM multi-target collaborative planning method for improving the voltage stability comprises the following steps of: s1, selecting a candidate bus as an installation position of a STATCOM by adopting a sensitivity analysis method; S2, generating a first generation data population by using a second generation non-dominant sorting genetic algorithm based on the candidate busbar screen, wherein the control variables comprise the initialization capacity of a single STATCOM and the abandoned wind proportion of a wind farm; S3, calculating a static voltage stability index of the wind power system, calculating an optimal power flow by taking the power generation cost of the generator as a target, and comparing the power generation cost of using the preventive control with the power generation cost of not using the preventive control; S4, simulating uncertainty of wind power outpu