To maintain the frequency stability of power systems integrated with large-scale renewable energy sources(RESs),a frequency-constrained unit commitment(FCUC)model is proposed,which incorporates a coordinated frequency...To maintain the frequency stability of power systems integrated with large-scale renewable energy sources(RESs),a frequency-constrained unit commitment(FCUC)model is proposed,which incorporates a coordinated frequency control strategy of wind turbines and energy storage system(WT-ESS),a vital component for enhancing frequency regulation capacity of wind farms.Analytical formulations for the maximum rate of change of frequency(RoCoF)and steady-state frequency deviation are derived for both serial control and parallel control,accounting for the output-limited state of energy storage under serial control.To address the problem of solution slowness caused by the strong nonlinear frequency nadir constraints,a model-based multi-directional bilayer solution method is proposed.This method employs the simulation model to detect whether the frequency nadir constraint is active and generates parallel optimized cuts in three directions.Simulation results on the IEEE 39-bus test system demonstrate that the proposed FCUC model and solution method could accurately reflect the primary frequency regulation(PFR)characteristics of WT-ESS.Furthermore,the coordinated frequency control strategy effectively reduces overall operating costs while ensuring frequency security.展开更多
The increasing penetration of renewable energy sources(RESs)brings great challenges to the frequency security of power systems.The traditional frequency-constrained unit commitment(FCUC)analyzes frequency by simplifyi...The increasing penetration of renewable energy sources(RESs)brings great challenges to the frequency security of power systems.The traditional frequency-constrained unit commitment(FCUC)analyzes frequency by simplifying the average system frequency and ignoring numerous induction machines(IMs)in load,which may underestimate the risk and increase the operational cost.In this paper,we consider a multiarea frequency response(MAFR)model to capture the frequency dynamics in the unit scheduling problem,in which regional frequency security and the inertia of IM load are modeled with high-dimension differential algebraic equations.A multi-area FCUC(MFCUC)is formulated as mixed-integer nonlinear programming(MINLP)on the basis of the MAFR model.Then,we develop a multi-direction decomposition algorithm to solve the MFCUC efficiently.The original MINLP is decomposed into a master problem and subproblems.The subproblems check the nonlinear frequency dynamics and generate linear optimization cuts for the master problem to improve the frequency security in its optimal solution.Case studies on the modified IEEE 39-bus system and IEEE 118-bus system show a great reduction in operational costs.Moreover,simulation results verify the ability of the proposed MAFR model to reflect regional frequency security and the available inertia of IMs in unit scheduling.展开更多
基金supported in part by the National Natural Science Foundation of China(No.52107082)by Major Talents Program of Guangxi of China.
文摘To maintain the frequency stability of power systems integrated with large-scale renewable energy sources(RESs),a frequency-constrained unit commitment(FCUC)model is proposed,which incorporates a coordinated frequency control strategy of wind turbines and energy storage system(WT-ESS),a vital component for enhancing frequency regulation capacity of wind farms.Analytical formulations for the maximum rate of change of frequency(RoCoF)and steady-state frequency deviation are derived for both serial control and parallel control,accounting for the output-limited state of energy storage under serial control.To address the problem of solution slowness caused by the strong nonlinear frequency nadir constraints,a model-based multi-directional bilayer solution method is proposed.This method employs the simulation model to detect whether the frequency nadir constraint is active and generates parallel optimized cuts in three directions.Simulation results on the IEEE 39-bus test system demonstrate that the proposed FCUC model and solution method could accurately reflect the primary frequency regulation(PFR)characteristics of WT-ESS.Furthermore,the coordinated frequency control strategy effectively reduces overall operating costs while ensuring frequency security.
基金supported by the Science and Technology Project of State Grid Hebei Electric Power Company Limited(No.kj2021-073)。
文摘The increasing penetration of renewable energy sources(RESs)brings great challenges to the frequency security of power systems.The traditional frequency-constrained unit commitment(FCUC)analyzes frequency by simplifying the average system frequency and ignoring numerous induction machines(IMs)in load,which may underestimate the risk and increase the operational cost.In this paper,we consider a multiarea frequency response(MAFR)model to capture the frequency dynamics in the unit scheduling problem,in which regional frequency security and the inertia of IM load are modeled with high-dimension differential algebraic equations.A multi-area FCUC(MFCUC)is formulated as mixed-integer nonlinear programming(MINLP)on the basis of the MAFR model.Then,we develop a multi-direction decomposition algorithm to solve the MFCUC efficiently.The original MINLP is decomposed into a master problem and subproblems.The subproblems check the nonlinear frequency dynamics and generate linear optimization cuts for the master problem to improve the frequency security in its optimal solution.Case studies on the modified IEEE 39-bus system and IEEE 118-bus system show a great reduction in operational costs.Moreover,simulation results verify the ability of the proposed MAFR model to reflect regional frequency security and the available inertia of IMs in unit scheduling.
