The synchronizing torque of a power system may be weakened by increasing installation of static power converters accompanied by renewable energy resources because they used to trade their favorable active power by syn...The synchronizing torque of a power system may be weakened by increasing installation of static power converters accompanied by renewable energy resources because they used to trade their favorable active power by synchronizing their output voltage with the one at the point of common coupling. In the circumstances, a concept of Virtual Synchronous Machine (VSM) is proposed, where the self-commutated power converters are emulating synchronous generators. This paper describes a converter control to contribute to enhancing the synchronizing torque. The proposed control is similar to the VSM but it simply realizes active power trades among power generation units including converter-based generators by modulating phase angles of their output voltages. Therefore, it can provide an effective support to regulate the system frequency where the total rated power of the converter-based generators increases as much as the one of conventional rotating generators like a microgrid. This paper especially focuses on its robustness where the number of converter-based generators is increased or they are dispersed in the power network. The effectiveness is verified by simulation study based on instantaneous values.展开更多
A big step forward to improve power system monitoring and performance, continued load growth without a corresponding increase in transmission resources has resulted in reduced operational margins for many power system...A big step forward to improve power system monitoring and performance, continued load growth without a corresponding increase in transmission resources has resulted in reduced operational margins for many power systems worldwide and has led to operation of power systems closer to their stability limits and to power exchange in new patterns. These issues, as well as the on-going worldwide trend towards deregulation of the entire industry on the one hand and the increased need for accurate and better network monitoring on the other hand, force power utilities exposed to this pressure to demand new solutions for wide area monitoring, protection and control. Wide-area monitoring, protection, and control require communicating the specific-node information to a remote station but all information should be time synchronized so that to neutralize the time difference between information. It gives a complete simultaneous snap shot of the power system. The conventional system is not able to satisfy the time-synchronized requirement of power system. Phasor Measurement Unit (PMU) is enabler of time-synchronized measurement, it communicate the synchronized local information to remote station.展开更多
为提升含高比例电力电子设备的电力系统暂态稳定性,提出一种基于广域测量系统(wide area measurement system,WAMS)的静止无功补偿器(static var compensator,SVC)优化控制策略。通过同步相量测量单元实时获取发电机母线电压相量,构建...为提升含高比例电力电子设备的电力系统暂态稳定性,提出一种基于广域测量系统(wide area measurement system,WAMS)的静止无功补偿器(static var compensator,SVC)优化控制策略。通过同步相量测量单元实时获取发电机母线电压相量,构建以发电机电功率与机械功率偏差最小为目标函数的粒子群优化模型,并结合电压幅值与相角灵敏度系数动态计算SVC最优无功功率注入量。创新性引入灵敏度系数刻画发电机有功功率对SVC无功功率的依赖关系,实现多发电机转子角振荡协同阻尼。在DIgSILENT PowerFactory平台搭建IEEE 14节点系统,仿真结果表明,所提策略可有效降低转子角振荡幅度及斜率,使临界清除时间延长40 ms。与传统本地控制方法相比,所提方法突破了单一振荡阻尼限制,利用WAMS信息实现多机协调控制,为提升复杂电力系统暂态稳定性提供了新思路。展开更多
对电压幅度暂变的最大补偿时间是串联型电能质量控制器(series power quality controllers,SPQC)重要性能指标。若没有额外直流储能元件,传统的同相位控制或能量优化控制只能提供有限的补偿时间。该文对SPQC提出一种新型控制策略,它在...对电压幅度暂变的最大补偿时间是串联型电能质量控制器(series power quality controllers,SPQC)重要性能指标。若没有额外直流储能元件,传统的同相位控制或能量优化控制只能提供有限的补偿时间。该文对SPQC提出一种新型控制策略,它在负载电压控制的同时,自动地从电源吸收部分有功功率来补偿其系统损耗,从而提高最大可补偿时间;甚至在没有额外直流储能元件时还具有持续补偿能力。采用负载电流相量为参考相量的新型相量图表示方法,使得SPQC系统内各相关变量之间的关系更加清晰简单。在电源电压幅度暂变和额定状态,分别对系统进行相应的相量图分析,得到采用这种新型控制策略的定量补偿电压幅度、可完全补偿的最大程度电压暂低以及系统的功率流动方式。根据系统能量平衡关系,提出该新型控制策略的一种简单统一实现方法。计算机仿真和原型实验验证了所得结论。展开更多
文摘The synchronizing torque of a power system may be weakened by increasing installation of static power converters accompanied by renewable energy resources because they used to trade their favorable active power by synchronizing their output voltage with the one at the point of common coupling. In the circumstances, a concept of Virtual Synchronous Machine (VSM) is proposed, where the self-commutated power converters are emulating synchronous generators. This paper describes a converter control to contribute to enhancing the synchronizing torque. The proposed control is similar to the VSM but it simply realizes active power trades among power generation units including converter-based generators by modulating phase angles of their output voltages. Therefore, it can provide an effective support to regulate the system frequency where the total rated power of the converter-based generators increases as much as the one of conventional rotating generators like a microgrid. This paper especially focuses on its robustness where the number of converter-based generators is increased or they are dispersed in the power network. The effectiveness is verified by simulation study based on instantaneous values.
文摘A big step forward to improve power system monitoring and performance, continued load growth without a corresponding increase in transmission resources has resulted in reduced operational margins for many power systems worldwide and has led to operation of power systems closer to their stability limits and to power exchange in new patterns. These issues, as well as the on-going worldwide trend towards deregulation of the entire industry on the one hand and the increased need for accurate and better network monitoring on the other hand, force power utilities exposed to this pressure to demand new solutions for wide area monitoring, protection and control. Wide-area monitoring, protection, and control require communicating the specific-node information to a remote station but all information should be time synchronized so that to neutralize the time difference between information. It gives a complete simultaneous snap shot of the power system. The conventional system is not able to satisfy the time-synchronized requirement of power system. Phasor Measurement Unit (PMU) is enabler of time-synchronized measurement, it communicate the synchronized local information to remote station.
文摘为提升含高比例电力电子设备的电力系统暂态稳定性,提出一种基于广域测量系统(wide area measurement system,WAMS)的静止无功补偿器(static var compensator,SVC)优化控制策略。通过同步相量测量单元实时获取发电机母线电压相量,构建以发电机电功率与机械功率偏差最小为目标函数的粒子群优化模型,并结合电压幅值与相角灵敏度系数动态计算SVC最优无功功率注入量。创新性引入灵敏度系数刻画发电机有功功率对SVC无功功率的依赖关系,实现多发电机转子角振荡协同阻尼。在DIgSILENT PowerFactory平台搭建IEEE 14节点系统,仿真结果表明,所提策略可有效降低转子角振荡幅度及斜率,使临界清除时间延长40 ms。与传统本地控制方法相比,所提方法突破了单一振荡阻尼限制,利用WAMS信息实现多机协调控制,为提升复杂电力系统暂态稳定性提供了新思路。
文摘对电压幅度暂变的最大补偿时间是串联型电能质量控制器(series power quality controllers,SPQC)重要性能指标。若没有额外直流储能元件,传统的同相位控制或能量优化控制只能提供有限的补偿时间。该文对SPQC提出一种新型控制策略,它在负载电压控制的同时,自动地从电源吸收部分有功功率来补偿其系统损耗,从而提高最大可补偿时间;甚至在没有额外直流储能元件时还具有持续补偿能力。采用负载电流相量为参考相量的新型相量图表示方法,使得SPQC系统内各相关变量之间的关系更加清晰简单。在电源电压幅度暂变和额定状态,分别对系统进行相应的相量图分析,得到采用这种新型控制策略的定量补偿电压幅度、可完全补偿的最大程度电压暂低以及系统的功率流动方式。根据系统能量平衡关系,提出该新型控制策略的一种简单统一实现方法。计算机仿真和原型实验验证了所得结论。
