Calculation of static voltage stability margin(SVSM)of AC/DC power systems with lots of renewable energy sources(RESs)integration requires consideration of uncertain load growth and renewable energy generation output....Calculation of static voltage stability margin(SVSM)of AC/DC power systems with lots of renewable energy sources(RESs)integration requires consideration of uncertain load growth and renewable energy generation output.This paper presents a bi-level optimal power flow(BLOPF)model to identify the worst-case SVSM of an AC/DC power system with line commutation converter-based HVDC and multi-terminal voltage sourced converter-based HVDC transmission lines.Constraints of uncertain load growth’s hypercone model and control mode switching of DC converter stations are considered in the BLOPF model.Moreover,uncertain RES output fluctuations are described as intervals,and two three-level optimal power flow(TLOPF)models are established to identify interval bounds of the system worst-case SVSM.The two TLOPF models are both transformed into max–min bi-level optimization models according to independent characteristics of different uncertain variables.Then,transforming the inner level model into its dual form,max–min BLOPF models are simplified to single-level optimization models for direct solution.Calculation results on the modified IEEE-39 bus AC/DC case and an actual large-scale AC/DC case in China indicate correctness and efficiency of the proposed identification method.展开更多
A unified optimal power flow(OPF) model for AC/DC grids integrated with natural gas systems is proposed for the real-time scheduling of power systems.Herein, the primary physical couplings underlying this coordinated ...A unified optimal power flow(OPF) model for AC/DC grids integrated with natural gas systems is proposed for the real-time scheduling of power systems.Herein, the primary physical couplings underlying this coordinated system are modeled and investigated. In addition, the uncertainties of gas loads are considered when studying the role of gas supply for gas-fired units in power system operations. The nonlinear gas system constraints are converted to the second-order cone forms that allow for the use of the Benders decomposition techniques and the interior-point method to obtain the optimal solution. The numerical results of the modified IEEE 118-bus test system that integrates the Belgium 20-node natural gas system demonstrate the effectiveness of the proposed model. The effects of gas demand uncertainties on the optimal schedule of thermal generators are investigated as well.展开更多
This paper employs an efficacious analytical tool,adaptive simplified human learning optimization(ASHLO)algorithm,to solve optimal power flow(OPF)problem in AC/DC hybrid power system,considering valve-point loading ef...This paper employs an efficacious analytical tool,adaptive simplified human learning optimization(ASHLO)algorithm,to solve optimal power flow(OPF)problem in AC/DC hybrid power system,considering valve-point loading effects of generators,carbon tax,and prohibited operating zones of generators,respectively.ASHLO algorithm,involves random learning operator,individual learning operator,social learning operator and adaptive strategies.To compare and analyze the computation performance of the ASHLO method,the proposed ASHLO method and other heuristic intelligent optimization methods are employed to solve OPF problem on the modified IEEE 30-bus and 118-bus AC/DC hybrid test system.Numerical results indicate that the ASHLO method has good convergent property and robustness.Meanwhile,the impacts of wind speeds and locations of HVDC transmission line integrated into the AC network on the OPF results are systematically analyzed.展开更多
Conversion of hourly dispatch cases derived using DC optimal power flow(DCOPF)to AC power flow(ACPF)case is often challenging and requires arduous human analysis and intervention.This paper proposes an automated two-s...Conversion of hourly dispatch cases derived using DC optimal power flow(DCOPF)to AC power flow(ACPF)case is often challenging and requires arduous human analysis and intervention.This paper proposes an automated two-stage approach to solve ACPF formulated from DCOPF dispatch cases.The first stage involved the use of the conventional Newton Raphson method to solve the ACPF from flat start,then ACPF cases that are unsolvable in the first stage are subjected to a hotstarting incremental method,based on homotopy continuation,in the second stage.Critical tasks such as the addition of reactive power compensation and tuning of voltage setpoints that typically require human intervention were automated using a criteriabased selection method and optimal power flow respectively.Two datasets with hourly dispatches for the 243-bus reduced WECC system were used to test the proposed method.The algorithm was able to convert 100%of the first set of dispatch cases to solved ACPF cases.In the second dataset with suspect dispatch cases to represent an extreme conversion scenario,the algorithm created solved ACPF cases that satisfied a defined success criterion for 77.8%of the dispatch cases.The average run time for the hotstarting algorithm to create a solved ACPF case for a dispatch was less than 1 minute for the reduced WECC system.展开更多
随着电力系统中多类型直流线路占比的逐步提升,调度系统与异构平台间的潮流数据交换需求明显增大,亟需研究新形态下交直流混联系统的潮流计算数据生成问题。该文从拓扑转换、网络拓扑分析、设备建模以及数据生成策略4个主要步骤,实现含...随着电力系统中多类型直流线路占比的逐步提升,调度系统与异构平台间的潮流数据交换需求明显增大,亟需研究新形态下交直流混联系统的潮流计算数据生成问题。该文从拓扑转换、网络拓扑分析、设备建模以及数据生成策略4个主要步骤,实现含交直流系统的基于可扩展标记语言的通用信息模型(common information model/extensible markup language,CIM/XML)数据到潮流计算输入数据的转换。首先,该文从设备间开关拓扑的角度,进行深度优先算法(depth first search,DFS)搜索和设备拓扑拼接,实现开关/节点模型到母线/支路模型的转换;其次,在筛选出活拓扑岛、剔除不带电设备后,着重分析了CIM/XML中换流器建模对交直流节点选取的影响,进而提出了直流节点选取规则和具备普适性的直流数据生成策略。最后,以某地调度500kV及以上交直流网络导出的CIM/XML数据为算例,潮流计算结果与数据采集与监视控制系统(supervisory control and data acquisition,SCADA)量测数据比对验证所提策略的有效性。展开更多
进化类算法和内点法交替迭代的混合算法在求解含电压源换流器的高压直流输电(voltage source converter basedhigh voltage direct current,VSC-HVDC)的交直流系统最优潮流(optimal power flow,OPF)问题时由于截断误差的影响和VSC-HVDC...进化类算法和内点法交替迭代的混合算法在求解含电压源换流器的高压直流输电(voltage source converter basedhigh voltage direct current,VSC-HVDC)的交直流系统最优潮流(optimal power flow,OPF)问题时由于截断误差的影响和VSC-HVDC控制方式的限制,容易发生振荡,因此提出一种基于差分进化(differential evolution,DE)和原—对偶内点法(primal-dual interior point method,PDIPM)的统一混合迭代算法。算法的主要思想是以DE算法为框架,对离散变量进行优化,在DE算法的每一次迭代过程中,采用PDIPM对每个DE个体进行连续变量的优化和适应度评估。由于采用PDIPM进行DE种群适应度评估,无需设定VSC-HVDC的控制方式,因此提高了算法的全局寻优能力。多个算例结果表明,该混合算法数值稳定性高,寻优能力强,能很好地解决含两端、多端、多馈入VSC-HVDC的交直流系统最优潮流问题。展开更多
多端柔性直流输电系统(voltage source converter based multi-terminal direct current system,VSC-MTDC)是在两端直流输电基础上发展而来的直流输电系统,可靠性高、适用于海上风电并网等场景,相应的控制策略更加多样,其潮流模型也更...多端柔性直流输电系统(voltage source converter based multi-terminal direct current system,VSC-MTDC)是在两端直流输电基础上发展而来的直流输电系统,可靠性高、适用于海上风电并网等场景,相应的控制策略更加多样,其潮流模型也更加复杂。该文分析VSC换流站和MTDC的稳态模型,研究可适用于VSC-MTDC的不同拓扑和连接方式的潮流模型;研究多端直流各种控制策略潮流计算模型的不同点并推导出其方程。在此基础上,提出一种兼具统一迭代法和交替迭代法优点的含VSC-MTDC交直流系统潮流算法,给出初值和边界条件求解方法,对于不同直流拓扑和交流系统都能够进行求解。最后通过2个实际算例验证该文潮流模型的有效性和收敛性,对于不同控制方式、不同运行场景和直流拓扑都能够迅速、稳定收敛。展开更多
提出一种基于带精英策略的快速非支配排序遗传算法(non-dominated sorting genetic algorithm-II,NSGA-II)和逼近理想解排序(technique for order preference by similarity to ideal solution,TOPSIS)的含VSC-HVDC交直流系统多目标最...提出一种基于带精英策略的快速非支配排序遗传算法(non-dominated sorting genetic algorithm-II,NSGA-II)和逼近理想解排序(technique for order preference by similarity to ideal solution,TOPSIS)的含VSC-HVDC交直流系统多目标最优潮流算法,统一协调系统运行的经济性及环保要求等目标。首先,基于含VSC-HVDC交直流系统的稳态模型,建立了综合考虑网络损耗和环境因素的多目标最优潮流模型;然后,采用混合编码方式,通过NSGA-II得到帕累托最优解集;最后,采用TOPSIS法评估各决策方案的相对优劣,以帮助运行人员选取有效的折中解。基于IEEE 14节点系统和IEEE 118节点系统的算例结果验证了所提方法的有效性。展开更多
电压源换流器(voltage source converter,VSC)在稳态模型和工作原理上与传统高压直流输电(high voltage directcurrent,HVDC)的换流器有本质区别,因此传统的交直流系统最优潮流计算方法不适用于含基于电压源换流器高压直流输电(VSC base...电压源换流器(voltage source converter,VSC)在稳态模型和工作原理上与传统高压直流输电(high voltage directcurrent,HVDC)的换流器有本质区别,因此传统的交直流系统最优潮流计算方法不适用于含基于电压源换流器高压直流输电(VSC based HVDC,VSC-HVDC)的交直流系统。讨论一种适用于原对偶内点法(primal-dual interior-pointmethod,PDIPM)和预测校正内点法(predictor-corrector PDIPM,PCPDIPM)解最优潮流的VSC-HVDC稳态模型。基于该稳态模型,将VSC-HVDC直流网络与交流系统结合起来,对交直流系统进行联立求解,并对多组算例进行仿真和分析,算例结果表明原对偶内点法在解决含VSC-HVDC的最优潮流问题的能力上,保持了传统内点法最优潮流的高效性,而在同样的条件下,预测–校正内点法迭代次数大大少于原对偶内点法。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51977080)the Natural Science Foundation of Guangdong Province(Grant No.2022A1515010332)supported by the U.S.National Science Foundation(Grant#2124849).
文摘Calculation of static voltage stability margin(SVSM)of AC/DC power systems with lots of renewable energy sources(RESs)integration requires consideration of uncertain load growth and renewable energy generation output.This paper presents a bi-level optimal power flow(BLOPF)model to identify the worst-case SVSM of an AC/DC power system with line commutation converter-based HVDC and multi-terminal voltage sourced converter-based HVDC transmission lines.Constraints of uncertain load growth’s hypercone model and control mode switching of DC converter stations are considered in the BLOPF model.Moreover,uncertain RES output fluctuations are described as intervals,and two three-level optimal power flow(TLOPF)models are established to identify interval bounds of the system worst-case SVSM.The two TLOPF models are both transformed into max–min bi-level optimization models according to independent characteristics of different uncertain variables.Then,transforming the inner level model into its dual form,max–min BLOPF models are simplified to single-level optimization models for direct solution.Calculation results on the modified IEEE-39 bus AC/DC case and an actual large-scale AC/DC case in China indicate correctness and efficiency of the proposed identification method.
文摘A unified optimal power flow(OPF) model for AC/DC grids integrated with natural gas systems is proposed for the real-time scheduling of power systems.Herein, the primary physical couplings underlying this coordinated system are modeled and investigated. In addition, the uncertainties of gas loads are considered when studying the role of gas supply for gas-fired units in power system operations. The nonlinear gas system constraints are converted to the second-order cone forms that allow for the use of the Benders decomposition techniques and the interior-point method to obtain the optimal solution. The numerical results of the modified IEEE 118-bus test system that integrates the Belgium 20-node natural gas system demonstrate the effectiveness of the proposed model. The effects of gas demand uncertainties on the optimal schedule of thermal generators are investigated as well.
基金supported by National Natural Science Foundation of China(No.51377103)the technology project of State Grid Corporation of China:Research on Multi-Level Decomposition Coordination of the Pareto Set of Multi-Objective Optimization Problem in Bulk Power System(No.SGSXDKYDWKJ2015-001)the support from State Energy Smart Grid R&D Center(SHANGHAI)
文摘This paper employs an efficacious analytical tool,adaptive simplified human learning optimization(ASHLO)algorithm,to solve optimal power flow(OPF)problem in AC/DC hybrid power system,considering valve-point loading effects of generators,carbon tax,and prohibited operating zones of generators,respectively.ASHLO algorithm,involves random learning operator,individual learning operator,social learning operator and adaptive strategies.To compare and analyze the computation performance of the ASHLO method,the proposed ASHLO method and other heuristic intelligent optimization methods are employed to solve OPF problem on the modified IEEE 30-bus and 118-bus AC/DC hybrid test system.Numerical results indicate that the ASHLO method has good convergent property and robustness.Meanwhile,the impacts of wind speeds and locations of HVDC transmission line integrated into the AC network on the OPF results are systematically analyzed.
基金This work was supported by the ERC Program of the National Science Foundation and DOE under NSF Award Number EEC-1041877the CURENT Industry Partnership Program,and the Bredesen Centre,University of Tennessee,Knoxville.
文摘Conversion of hourly dispatch cases derived using DC optimal power flow(DCOPF)to AC power flow(ACPF)case is often challenging and requires arduous human analysis and intervention.This paper proposes an automated two-stage approach to solve ACPF formulated from DCOPF dispatch cases.The first stage involved the use of the conventional Newton Raphson method to solve the ACPF from flat start,then ACPF cases that are unsolvable in the first stage are subjected to a hotstarting incremental method,based on homotopy continuation,in the second stage.Critical tasks such as the addition of reactive power compensation and tuning of voltage setpoints that typically require human intervention were automated using a criteriabased selection method and optimal power flow respectively.Two datasets with hourly dispatches for the 243-bus reduced WECC system were used to test the proposed method.The algorithm was able to convert 100%of the first set of dispatch cases to solved ACPF cases.In the second dataset with suspect dispatch cases to represent an extreme conversion scenario,the algorithm created solved ACPF cases that satisfied a defined success criterion for 77.8%of the dispatch cases.The average run time for the hotstarting algorithm to create a solved ACPF case for a dispatch was less than 1 minute for the reduced WECC system.
文摘随着电力系统中多类型直流线路占比的逐步提升,调度系统与异构平台间的潮流数据交换需求明显增大,亟需研究新形态下交直流混联系统的潮流计算数据生成问题。该文从拓扑转换、网络拓扑分析、设备建模以及数据生成策略4个主要步骤,实现含交直流系统的基于可扩展标记语言的通用信息模型(common information model/extensible markup language,CIM/XML)数据到潮流计算输入数据的转换。首先,该文从设备间开关拓扑的角度,进行深度优先算法(depth first search,DFS)搜索和设备拓扑拼接,实现开关/节点模型到母线/支路模型的转换;其次,在筛选出活拓扑岛、剔除不带电设备后,着重分析了CIM/XML中换流器建模对交直流节点选取的影响,进而提出了直流节点选取规则和具备普适性的直流数据生成策略。最后,以某地调度500kV及以上交直流网络导出的CIM/XML数据为算例,潮流计算结果与数据采集与监视控制系统(supervisory control and data acquisition,SCADA)量测数据比对验证所提策略的有效性。
文摘进化类算法和内点法交替迭代的混合算法在求解含电压源换流器的高压直流输电(voltage source converter basedhigh voltage direct current,VSC-HVDC)的交直流系统最优潮流(optimal power flow,OPF)问题时由于截断误差的影响和VSC-HVDC控制方式的限制,容易发生振荡,因此提出一种基于差分进化(differential evolution,DE)和原—对偶内点法(primal-dual interior point method,PDIPM)的统一混合迭代算法。算法的主要思想是以DE算法为框架,对离散变量进行优化,在DE算法的每一次迭代过程中,采用PDIPM对每个DE个体进行连续变量的优化和适应度评估。由于采用PDIPM进行DE种群适应度评估,无需设定VSC-HVDC的控制方式,因此提高了算法的全局寻优能力。多个算例结果表明,该混合算法数值稳定性高,寻优能力强,能很好地解决含两端、多端、多馈入VSC-HVDC的交直流系统最优潮流问题。
文摘多端柔性直流输电系统(voltage source converter based multi-terminal direct current system,VSC-MTDC)是在两端直流输电基础上发展而来的直流输电系统,可靠性高、适用于海上风电并网等场景,相应的控制策略更加多样,其潮流模型也更加复杂。该文分析VSC换流站和MTDC的稳态模型,研究可适用于VSC-MTDC的不同拓扑和连接方式的潮流模型;研究多端直流各种控制策略潮流计算模型的不同点并推导出其方程。在此基础上,提出一种兼具统一迭代法和交替迭代法优点的含VSC-MTDC交直流系统潮流算法,给出初值和边界条件求解方法,对于不同直流拓扑和交流系统都能够进行求解。最后通过2个实际算例验证该文潮流模型的有效性和收敛性,对于不同控制方式、不同运行场景和直流拓扑都能够迅速、稳定收敛。
文摘提出一种基于带精英策略的快速非支配排序遗传算法(non-dominated sorting genetic algorithm-II,NSGA-II)和逼近理想解排序(technique for order preference by similarity to ideal solution,TOPSIS)的含VSC-HVDC交直流系统多目标最优潮流算法,统一协调系统运行的经济性及环保要求等目标。首先,基于含VSC-HVDC交直流系统的稳态模型,建立了综合考虑网络损耗和环境因素的多目标最优潮流模型;然后,采用混合编码方式,通过NSGA-II得到帕累托最优解集;最后,采用TOPSIS法评估各决策方案的相对优劣,以帮助运行人员选取有效的折中解。基于IEEE 14节点系统和IEEE 118节点系统的算例结果验证了所提方法的有效性。
文摘电压源换流器(voltage source converter,VSC)在稳态模型和工作原理上与传统高压直流输电(high voltage directcurrent,HVDC)的换流器有本质区别,因此传统的交直流系统最优潮流计算方法不适用于含基于电压源换流器高压直流输电(VSC based HVDC,VSC-HVDC)的交直流系统。讨论一种适用于原对偶内点法(primal-dual interior-pointmethod,PDIPM)和预测校正内点法(predictor-corrector PDIPM,PCPDIPM)解最优潮流的VSC-HVDC稳态模型。基于该稳态模型,将VSC-HVDC直流网络与交流系统结合起来,对交直流系统进行联立求解,并对多组算例进行仿真和分析,算例结果表明原对偶内点法在解决含VSC-HVDC的最优潮流问题的能力上,保持了传统内点法最优潮流的高效性,而在同样的条件下,预测–校正内点法迭代次数大大少于原对偶内点法。