It is an important topic to improve the redundancy of optimized configuration to resist the local failure in topology optimization of continuum structures.Such a fail-safe topology optimization problem has been solved...It is an important topic to improve the redundancy of optimized configuration to resist the local failure in topology optimization of continuum structures.Such a fail-safe topology optimization problem has been solved effectively in the ficld of statics.In this paper,the fail-safe topology optimization problem is extended to the field of frequency topology optimization.Based on the independent continuous mapping(ICM)method,the model of fail-safe topology optimization is established with the objective of minimal weight integrating with the discrete condition of topological variables and the constraint of the fundamental frequency.The fail-safe optimization model established above is substituted by a sequence of subproblems in the form of the quadratic program with exact second-order information and solved efficiently by the dual sequence quadratic programming(DSQP)algorithm.The numerical result reveals that the optimized fail-safe structure has more complex configuration and preserved materials than the structure obtained from the traditional frequency topology optimization,which means that the optimized fail-safe structure has higher redundancy.Moreover,the optimized fail-safe structure guarantees that the natural frequency meets the constraint of fundamental frequency when the local failure ocurs,which can avoid the structural frequency to be sensitive to local failure.The fail-safe optimirzation topology model is proved effective and feasible by four numerical examples.展开更多
Shape and size optimization with frequency constraints is a highly nonlinear problem withmixed design variables,non-convex search space,and multiple local optima.Therefore,a hybrid sine cosine firefly algorithm(HSCFA)...Shape and size optimization with frequency constraints is a highly nonlinear problem withmixed design variables,non-convex search space,and multiple local optima.Therefore,a hybrid sine cosine firefly algorithm(HSCFA)is proposed to acquire more accurate solutions with less finite element analysis.The full attraction model of firefly algorithm(FA)is analyzed,and the factors that affect its computational efficiency and accuracy are revealed.A modified FA with simplified attraction model and adaptive parameter of sine cosine algorithm(SCA)is proposed to reduce the computational complexity and enhance the convergence rate.Then,the population is classified,and different populations are updated by modified FA and SCA respectively.Besides,the random search strategy based on Lévy flight is adopted to update the stagnant or infeasible solutions to enhance the population diversity.Elitist selection technique is applied to save the promising solutions and further improve the convergence rate.Moreover,the adaptive penalty function is employed to deal with the constraints.Finally,the performance of HSCFA is demonstrated through the numerical examples with nonstructural masses and frequency constraints.The results show that HSCFA is an efficient and competitive tool for shape and size optimization problems with frequency constraints.展开更多
The increasing penetration of renewable energy resources degrades the frequency stability of power systems.The present work addresses this issue by proposing a look-ahead dispatch model of power systems based on a lin...The increasing penetration of renewable energy resources degrades the frequency stability of power systems.The present work addresses this issue by proposing a look-ahead dispatch model of power systems based on a linear alternating current optimal power flow framework with nonlinear frequency constraints.Meanwhile,the poor efficiency for solving this formulation is addressed by introducing a physics-informed neural network(PINN)to predict key frequency-control parameter values accurately.The PINN ensures that the learned results are applicable to the original physical frequency dynamics model,and applying the predicted parameter values enables the resulting dispatch model to be solved quickly and efficiently using readily available commercial solvers.The feasibility and advantages of the proposed model are demonstrated by the results of numerical computations applied to a modified IEEE 118-bus test system.展开更多
The increasing penetration of the renewable energy sources brings new challenges to the frequency security of power systems. In order to guarantee the system frequency security, frequency constraints are incorporated ...The increasing penetration of the renewable energy sources brings new challenges to the frequency security of power systems. In order to guarantee the system frequency security, frequency constraints are incorporated into unit commitment(UC) models. Due to the non-convex form of the frequency nadir constraint which makes the frequency constrained UC(FCUC) intractable, this letter proposes a revised support vector machine(SVM) based system parameter separating plane method to convexify it. Based on this data-driven convexification method, we obtain a tractable FCUC model which is formulated as a mixed-integer quadratic programming(MIQP) problem. Case studies indicate that the proposed method can obtain less conservative solution than the existing methods with higher efficiency.展开更多
In coastal regions of China,offshore wind farm ex-pansion has spurred extensive research to reduce operational costs in power systems with high penetration of wind power.However,frequent extreme weather conditions suc...In coastal regions of China,offshore wind farm ex-pansion has spurred extensive research to reduce operational costs in power systems with high penetration of wind power.However,frequent extreme weather conditions such as typhoons pose substantial challenges to system stability and security.Pre-vious research has intensively examined the steady-state opera-tions arising from typhoon-induced faults,with a limited em-phasis on the transient frequency dynamics inherent to such faults.To address this challenge,this paper proposes a frequen-cy-constrained unit commitment model that can promote ener-gy utilization and improve resilience.The proposed model ana-lyzes uncertainties stemming from transmission line failures and offshore wind generation through typhoon simulations.Two types of power disturbances resulting from typhoon-in-duced wind farm cutoff and grid islanding events are revealed.In addition,new frequency constraints are defined considering the changes in the topology of the power system.Further,the complex frequency nadir constraints are incorporated into a two-stage stochastic unit commitment model using the piece-wise linearization.Finally,the proposed model is verified by nu-merical experiments,and the results demonstrate that the pro-posed model can effectively enhance system resilience under ty-phoons and improve frequency dynamic characteristics following fault disturbances.展开更多
基金the National Natural Science Foundation of China(Grant 11872080).
文摘It is an important topic to improve the redundancy of optimized configuration to resist the local failure in topology optimization of continuum structures.Such a fail-safe topology optimization problem has been solved effectively in the ficld of statics.In this paper,the fail-safe topology optimization problem is extended to the field of frequency topology optimization.Based on the independent continuous mapping(ICM)method,the model of fail-safe topology optimization is established with the objective of minimal weight integrating with the discrete condition of topological variables and the constraint of the fundamental frequency.The fail-safe optimization model established above is substituted by a sequence of subproblems in the form of the quadratic program with exact second-order information and solved efficiently by the dual sequence quadratic programming(DSQP)algorithm.The numerical result reveals that the optimized fail-safe structure has more complex configuration and preserved materials than the structure obtained from the traditional frequency topology optimization,which means that the optimized fail-safe structure has higher redundancy.Moreover,the optimized fail-safe structure guarantees that the natural frequency meets the constraint of fundamental frequency when the local failure ocurs,which can avoid the structural frequency to be sensitive to local failure.The fail-safe optimirzation topology model is proved effective and feasible by four numerical examples.
基金supported by the NationalNatural Science Foundation of China(No.11672098).
文摘Shape and size optimization with frequency constraints is a highly nonlinear problem withmixed design variables,non-convex search space,and multiple local optima.Therefore,a hybrid sine cosine firefly algorithm(HSCFA)is proposed to acquire more accurate solutions with less finite element analysis.The full attraction model of firefly algorithm(FA)is analyzed,and the factors that affect its computational efficiency and accuracy are revealed.A modified FA with simplified attraction model and adaptive parameter of sine cosine algorithm(SCA)is proposed to reduce the computational complexity and enhance the convergence rate.Then,the population is classified,and different populations are updated by modified FA and SCA respectively.Besides,the random search strategy based on Lévy flight is adopted to update the stagnant or infeasible solutions to enhance the population diversity.Elitist selection technique is applied to save the promising solutions and further improve the convergence rate.Moreover,the adaptive penalty function is employed to deal with the constraints.Finally,the performance of HSCFA is demonstrated through the numerical examples with nonstructural masses and frequency constraints.The results show that HSCFA is an efficient and competitive tool for shape and size optimization problems with frequency constraints.
基金supported by the National Natural Science Foundation of China(No.52077060).
文摘The increasing penetration of renewable energy resources degrades the frequency stability of power systems.The present work addresses this issue by proposing a look-ahead dispatch model of power systems based on a linear alternating current optimal power flow framework with nonlinear frequency constraints.Meanwhile,the poor efficiency for solving this formulation is addressed by introducing a physics-informed neural network(PINN)to predict key frequency-control parameter values accurately.The PINN ensures that the learned results are applicable to the original physical frequency dynamics model,and applying the predicted parameter values enables the resulting dispatch model to be solved quickly and efficiently using readily available commercial solvers.The feasibility and advantages of the proposed model are demonstrated by the results of numerical computations applied to a modified IEEE 118-bus test system.
基金supported in part by the S&T Project of State Grid Corporation of China “Learning based Renewable Cluster Control and Coordinated Dispatch”(No. 5100-202199512A-0-5-ZN)。
文摘The increasing penetration of the renewable energy sources brings new challenges to the frequency security of power systems. In order to guarantee the system frequency security, frequency constraints are incorporated into unit commitment(UC) models. Due to the non-convex form of the frequency nadir constraint which makes the frequency constrained UC(FCUC) intractable, this letter proposes a revised support vector machine(SVM) based system parameter separating plane method to convexify it. Based on this data-driven convexification method, we obtain a tractable FCUC model which is formulated as a mixed-integer quadratic programming(MIQP) problem. Case studies indicate that the proposed method can obtain less conservative solution than the existing methods with higher efficiency.
基金This paper was supported by the Science and Technology Development Fund,MacauSAR(No.001/2024/SKL).
文摘In coastal regions of China,offshore wind farm ex-pansion has spurred extensive research to reduce operational costs in power systems with high penetration of wind power.However,frequent extreme weather conditions such as typhoons pose substantial challenges to system stability and security.Pre-vious research has intensively examined the steady-state opera-tions arising from typhoon-induced faults,with a limited em-phasis on the transient frequency dynamics inherent to such faults.To address this challenge,this paper proposes a frequen-cy-constrained unit commitment model that can promote ener-gy utilization and improve resilience.The proposed model ana-lyzes uncertainties stemming from transmission line failures and offshore wind generation through typhoon simulations.Two types of power disturbances resulting from typhoon-in-duced wind farm cutoff and grid islanding events are revealed.In addition,new frequency constraints are defined considering the changes in the topology of the power system.Further,the complex frequency nadir constraints are incorporated into a two-stage stochastic unit commitment model using the piece-wise linearization.Finally,the proposed model is verified by nu-merical experiments,and the results demonstrate that the pro-posed model can effectively enhance system resilience under ty-phoons and improve frequency dynamic characteristics following fault disturbances.
