随着新能源发电比例越来越高,其受电网三相不平衡的影响越来越明显,尤其负序超标是导致电力系统安全性降低的重要原因。统一潮流控制器(unified power flow controller,UPFC)具有调节各序电流输出的能力,可用于提升系统的平衡性。为此,...随着新能源发电比例越来越高,其受电网三相不平衡的影响越来越明显,尤其负序超标是导致电力系统安全性降低的重要原因。统一潮流控制器(unified power flow controller,UPFC)具有调节各序电流输出的能力,可用于提升系统的平衡性。为此,首先建立基于解耦-补偿原理的UPFC正序最优补偿潮流算法;其次构建UPFC的负序补偿电流控制模型,将电压不平衡补偿的优化求解问题归结为凸二次约束二次规划(quadratically constrained quadratic programming,QCQP)问题,并采用原-对偶内点法求取UPFC的负序电流最优输出值;最后提出计及正序网损与负序电压指标的负序电压补偿最优潮流(optimal power flow,OPF)计算方法以及区域负序电压总体补偿策略。通过算例分析验证所提出方法的可行性与有效性。展开更多
为了解决高比例新能源地区电网中新能源不确定性所导致的N-1故障线路过载问题,提出一种计及新能源不确定性并应用混合型潮流控制器(hybrid power flow controller,HPFC)控制模式的电网潮流优化方法。首先,建立了适应于多线路控制的HPFC...为了解决高比例新能源地区电网中新能源不确定性所导致的N-1故障线路过载问题,提出一种计及新能源不确定性并应用混合型潮流控制器(hybrid power flow controller,HPFC)控制模式的电网潮流优化方法。首先,建立了适应于多线路控制的HPFC稳态计算模型,并给出了在不同控制模式下的HPFC运行约束条件。其次,以电网有功网损和线路负载率指标为目标函数,考虑N-1安全约束和HPFC运行约束,建立应用HPFC控制模式的电网潮流优化模型。然后,通过模糊C均值聚类获取反映新能源出力、负荷不确定性的场景集合,并采用多目标多元宇宙优化算法(multi-objective multi-verse optimization,MOMVO)求解所提优化模型。最后,将所提潮流优化方法应用于江苏南通某地区电网。结果表明,所提方法能有效提高电网的经济性与静态安全性,且计算结果具有较好的稳定性。展开更多
On the basis of the theoretical analysis of a single-machine infinite-bus (SMIB), using the modified linearized Phil- lips-Heffron model installed with unified power flow controller (UPFC), the potential of the UP...On the basis of the theoretical analysis of a single-machine infinite-bus (SMIB), using the modified linearized Phil- lips-Heffron model installed with unified power flow controller (UPFC), the potential of the UPFC supplementary controller to enhance the dynamic stability of a power system is evaluated by measuring the electromechanical controllability through singular value decomposition (SVD) analysis. This controller is tuned to simultaneously shift the undamped electromeehanical modes to a prescribed zone in the s-plane. The problem of robust UPFC based damping controller is formulated as an optimization problem according to the eigenvalue-based multi-objective function comprising the damping factor, and the damping ratio of the undamped electromechanical modes to be solved using gravitational search algorithm (GSA) that has a strong ability to find the most optimistic results. The different loading conditions are simulated on a SMIB system and the rotor speed deviation, internal voltage deviation, DC voltage deviation and electrical power deviation responses are studied with the effect of this flexible AC transmission systems (FACTS) controller. The results reveal that the tuned GSA based UPFC controller using the proposed multi-objective function has an excellent capability in damping power system with low frequency oscillations and greatly enhances the dynamic stability of the power systems.展开更多
混合型潮流控制器(hybrid power flow controller,HPFC)可以有效解决风电并网系统中存在的支路潮流过载问题,且相较于统一潮流控制器成本更低。针对现有的HPFC潮流优化研究尚未计及支路潮流最大值约束和风电不确定性的问题,提出一种基...混合型潮流控制器(hybrid power flow controller,HPFC)可以有效解决风电并网系统中存在的支路潮流过载问题,且相较于统一潮流控制器成本更低。针对现有的HPFC潮流优化研究尚未计及支路潮流最大值约束和风电不确定性的问题,提出一种基于场景削减的含HPFC风电并网系统最优潮流模型。首先,建立HPFC的功率注入模型,并推导了注入功率表达式;其次,采用K均值算法削减风电、负荷概率场景,通过CH(+)指标选择最优场景集合;最后,建立兼顾发电机运行成本、系统网络损耗、正常运行及N-1故障下的支路负载率的多目标优化模型,采用多目标粒子群优化(multi-objective particle swarm optimization,MOPSO)算法进行求解,利用模糊满意度函数在Pareto解集中筛选出折衷解。在MATLAB中仿真验证所提方法的有效性,结果表明该方法可以计及风电不确定性,保证电网在不同场景下的安全经济运行。展开更多
针对模块化多电平统一电能质量调节器(modular multilevel unified power quality conditioner, MMC-UPQC)六桥臂结构下的单相桥臂故障问题,提出了一种五桥臂拓扑,这种新型拓扑可实现故障情况下的电能质量补偿。首先,对MMC-UPQC串并联...针对模块化多电平统一电能质量调节器(modular multilevel unified power quality conditioner, MMC-UPQC)六桥臂结构下的单相桥臂故障问题,提出了一种五桥臂拓扑,这种新型拓扑可实现故障情况下的电能质量补偿。首先,对MMC-UPQC串并联侧的数学模型进行分析,提出了一种复合模型预测控制(hybrid model predictive control,H-MPC),所提控制方法结合了有限集模型预测控制(finite-control-set model predictive control, FCS-MPC)以及快速模型预测控制(fast model predictive control, F-MPC)。然后,通过构建两侧独立的价值函数减少了控制方法的计算量,同时也实现了五桥臂解耦控制。最后,相比传统线性(例如PI)和非线性(例如无源控制passivity-based control,PBC)的控制策略,所提复合模型预测控制在电压补偿、负序电压抑制以及谐波电流补偿等方面具有一定优势,并在一定程度上避免了复杂的参数整定及坐标变化环节。仿真实验结果证明了所提控制方法的可行性和优越性。展开更多
文摘随着新能源发电比例越来越高,其受电网三相不平衡的影响越来越明显,尤其负序超标是导致电力系统安全性降低的重要原因。统一潮流控制器(unified power flow controller,UPFC)具有调节各序电流输出的能力,可用于提升系统的平衡性。为此,首先建立基于解耦-补偿原理的UPFC正序最优补偿潮流算法;其次构建UPFC的负序补偿电流控制模型,将电压不平衡补偿的优化求解问题归结为凸二次约束二次规划(quadratically constrained quadratic programming,QCQP)问题,并采用原-对偶内点法求取UPFC的负序电流最优输出值;最后提出计及正序网损与负序电压指标的负序电压补偿最优潮流(optimal power flow,OPF)计算方法以及区域负序电压总体补偿策略。通过算例分析验证所提出方法的可行性与有效性。
文摘On the basis of the theoretical analysis of a single-machine infinite-bus (SMIB), using the modified linearized Phil- lips-Heffron model installed with unified power flow controller (UPFC), the potential of the UPFC supplementary controller to enhance the dynamic stability of a power system is evaluated by measuring the electromechanical controllability through singular value decomposition (SVD) analysis. This controller is tuned to simultaneously shift the undamped electromeehanical modes to a prescribed zone in the s-plane. The problem of robust UPFC based damping controller is formulated as an optimization problem according to the eigenvalue-based multi-objective function comprising the damping factor, and the damping ratio of the undamped electromechanical modes to be solved using gravitational search algorithm (GSA) that has a strong ability to find the most optimistic results. The different loading conditions are simulated on a SMIB system and the rotor speed deviation, internal voltage deviation, DC voltage deviation and electrical power deviation responses are studied with the effect of this flexible AC transmission systems (FACTS) controller. The results reveal that the tuned GSA based UPFC controller using the proposed multi-objective function has an excellent capability in damping power system with low frequency oscillations and greatly enhances the dynamic stability of the power systems.
文摘随着分布式光伏等新能源接入电网的规模快速增长,给新能源电力汇聚、疏散、消纳和电网潮流优化控制带来严峻挑战。基于电力电子技术的柔性交流输电系统装置可有效提升输电网络的传输容量,由大容量Sen变压器(sen transformer,ST)和小容量统一潮流控制器(unified power flow controller,UPFC)组成的混合式潮流控制器(hybrid unified power flow controller,HPFC)在实现潮流连续调节的基础上,能够有效提升装置的经济性,具有很好的应用前景。为了确保HPFC调节潮流的准确性和可靠性,给出了HPFC容量分配的一般性方法及其主电路参数确定方法;为解决ST机械有载分接开关和UPFC电力电子开关二者响应速度的协调问题,提出了一种基于预测电流控制的潮流控制策略,并在Simulink中搭建220 kV双回线路及三机九节点系统进行仿真。仿真结果验证了HPFC容量分配方法正确有效,且预测电流控制策略能够合理计算抽头位置,减缓过渡电流对HPFC控制系统的冲击,使系统功率快速调节至目标值。
文摘针对模块化多电平统一电能质量调节器(modular multilevel unified power quality conditioner, MMC-UPQC)六桥臂结构下的单相桥臂故障问题,提出了一种五桥臂拓扑,这种新型拓扑可实现故障情况下的电能质量补偿。首先,对MMC-UPQC串并联侧的数学模型进行分析,提出了一种复合模型预测控制(hybrid model predictive control,H-MPC),所提控制方法结合了有限集模型预测控制(finite-control-set model predictive control, FCS-MPC)以及快速模型预测控制(fast model predictive control, F-MPC)。然后,通过构建两侧独立的价值函数减少了控制方法的计算量,同时也实现了五桥臂解耦控制。最后,相比传统线性(例如PI)和非线性(例如无源控制passivity-based control,PBC)的控制策略,所提复合模型预测控制在电压补偿、负序电压抑制以及谐波电流补偿等方面具有一定优势,并在一定程度上避免了复杂的参数整定及坐标变化环节。仿真实验结果证明了所提控制方法的可行性和优越性。