In this paper, damping of the low frequency oscillations of multi-machine multi-UPFC power systems is investigated based on adaptive input-output feedback linearization control (AIFLC) approach. Considering a three-phase symmetrical fault, ignoring the subtransient states of the synchronous machines, the nonlinear state equations of the system are derived in order to obtain the UPFC reference control signals as well as the system parameters estimation laws. The stability of the system controller is proved by Lyapunov theory. Moreover using the six reduced order model of synchronous machine, some simulation results are presented in order to verify the validity and effectiveness of the proposed control approach.

为更好地梳理概念，将低频振荡分析方法分为两大类，即针对系统模型平衡点的特征根方法以及沿着系统受扰轨迹的模式提取方法。平衡点特征根方法可进一步按采用的系统模型分为确定性的线性化模型、确定性的非线性模型和概率模型。这类方法与具体扰动无关，但只能反映系统在该平衡点附近的动态行为，故不适用于包含强非线性、变系数、相继故障或有离散控制的系统。受扰轨迹模式分析方法则从特定扰动下的时间响应曲线中提取振荡信息的时间序列，包括系统模型未知情况下（如实测轨迹）的信号处理法和系统模型已知情况下（如仿真轨迹）的分时段定常线性化法。在评述各种方法的基础上，提出改进的思路及有望突破的研究方向。

为更好地梳理概念，将低频振荡分析方法分为两大类，即针对系统模型平衡点的特征根方法以及沿着系统受扰轨迹的模式提取方法。平衡点特征根方法可进一步按采用的系统模型分为确定性的线性化模型、确定性的非线性模型和概率模型。这类方法与具体扰动无关，但只能反映系统在该平衡点附近的动态行为，故不适用于包含强非线性、变系数、相继故障或有离散控制的系统。受扰轨迹模式分析方法则从特定扰动下的时间响应曲线中提取振荡信息的时间序列，包括系统模型未知情况下（如实测轨迹）的信号处理法和系统模型已知情况下（如仿真轨迹）的分时段定常线性化法。在评述各种方法的基础上，提出改进的思路及有望突破的研究方向。

Based on the uniform damping thought and the identification of the low-frequency oscillation (LFO), the paper puts forward the design method of damping controllers which makes use of region pole assignment method to realize coordination damping control of LFO. First, the damping characteristics of power systems oscillation and the characteristics that machines are involved in oscillations are analyzed, and the condition and method of realizing uniform damping control are put forward. Then evaluating the damping based on the oscillation characteristics identification, the control object of uniform damping is determined. And reduced order models used to design controllers are deduced by the order reduction of identification models. Finally controllers’ parameters are calculated by poles assignment method which damp several oscillation modes that generator participated in. Because identified models consider fluencies of other machines and the control goal avoids decreasing damping of other modes in excess, the coordination of controllers is realized. At the same time, the feedback signal of controller is local and the decentralized coordinated control is realized. At last, take New England 10-machine 39-node system as example, the simulation proves controllers designed validity and robust, the method put forward a new thought for restraining LFO.

Based on the uniform damping thought and the identification of the low-frequency oscillation (LFO), the paper puts forward the design method of damping controllers which makes use of region pole assignment method to realize coordination damping control of LFO. First, the damping characteristics of power systems oscillation and the characteristics that machines are involved in oscillations are analyzed, and the condition and method of realizing uniform damping control are put forward. Then evaluating the damping based on the oscillation characteristics identification, the control object of uniform damping is determined. And reduced order models used to design controllers are deduced by the order reduction of identification models. Finally controllers’ parameters are calculated by poles assignment method which damp several oscillation modes that generator participated in. Because identified models consider fluencies of other machines and the control goal avoids decreasing damping of other modes in excess, the coordination of controllers is realized. At the same time, the feedback signal of controller is local and the decentralized coordinated control is realized. At last, take New England 10-machine 39-node system as example, the simulation proves controllers designed validity and robust, the method put forward a new thought for restraining LFO.

传统基于离线模型参数和典型运行方式设计的电力系统阻尼控制器存在适应性问题，提出一种基于辨识的自适应控制器设计方法，可解决一般自适应控制中快速性和准确性要求之间的矛盾。所用的多元自回归滑动平均模型(auto regressive moving averaging vector，ARMAV)辨识在电网正常运行过程中针对由负荷等随机扰动引起的类噪声信号进行；在综合考虑辨识误差、阻尼要求和稳定裕度基础上，提出阻尼控制零极点配置基本原则，并设计相应的遗传算法优化方法。为了充分检验上述辨识与控制系统的效果，基于广域测量平台对其进行软硬件实现，并在东北电网简化系统中进行实时数字仿真(real time digital simulation，RTDS)测试，实验结果说明了所提方法的可行性和有效性。

传统基于离线模型参数和典型运行方式设计的电力系统阻尼控制器存在适应性问题，提出一种基于辨识的自适应控制器设计方法，可解决一般自适应控制中快速性和准确性要求之间的矛盾。所用的多元自回归滑动平均模型(auto regressive moving averaging vector，ARMAV)辨识在电网正常运行过程中针对由负荷等随机扰动引起的类噪声信号进行；在综合考虑辨识误差、阻尼要求和稳定裕度基础上，提出阻尼控制零极点配置基本原则，并设计相应的遗传算法优化方法。为了充分检验上述辨识与控制系统的效果，基于广域测量平台对其进行软硬件实现，并在东北电网简化系统中进行实时数字仿真(real time digital simulation，RTDS)测试，实验结果说明了所提方法的可行性和有效性。

Research on low frequency oscillation of power grid based on multiple disturbances is the important basis to determine the dynamic stability of interconnected power grid. The paper proposed the concept of multiple disturbances based on the analysis of the power oscillation event happened in Central China Grid, and discovers that multiple disturbances are the important factor to cause low frequency oscillation. The fault chains method can simulate a typical disturbance sequence of flow transferring and overload of transmission lines caused by line faults. It was chosen to analysis power oscillations in interconnected power grid under multiple disturbances. The influence of operation modes on interconnected power grid is studied. The results show that the change of operation modes of the given power grid has a great impact on both the given power grid and another power gird which is connected to it. So the paper proposes a method by monitoring the occurrence sequences of the fault chains and the weak links to prevent low frequency oscillation which can provide the basis for power grid planning and dispatching operation.

Research on low frequency oscillation of power grid based on multiple disturbances is the important basis to determine the dynamic stability of interconnected power grid. The paper proposed the concept of multiple disturbances based on the analysis of the power oscillation event happened in Central China Grid, and discovers that multiple disturbances are the important factor to cause low frequency oscillation. The fault chains method can simulate a typical disturbance sequence of flow transferring and overload of transmission lines caused by line faults. It was chosen to analysis power oscillations in interconnected power grid under multiple disturbances. The influence of operation modes on interconnected power grid is studied. The results show that the change of operation modes of the given power grid has a great impact on both the given power grid and another power gird which is connected to it. So the paper proposes a method by monitoring the occurrence sequences of the fault chains and the weak links to prevent low frequency oscillation which can provide the basis for power grid planning and dispatching operation.

Automation offers laboratories the ability to improve patient care, enhance client and employee satisfaction, and increase workload capacity while maintaining a cost-effective department. "The overall objective of any organization's automation project is simple--to do more with less, better," states Davis. "We know our future is on the information systems side," Clarke states. "Vendors' investment in the development and creativity of automation is what is going to drive the future of the laboratory." "Implementing the automation solution was absolutely the right thing to do for Sacred Heart Health," says Wright. "With the transition complete, we are pleased with the results. All we want now is more automation that will enable us to do even more with what we have."

Automation offers laboratories the ability to improve patient care, enhance client and employee satisfaction, and increase workload capacity while maintaining a cost-effective department. "The overall objective of any organization's automation project is simple--to do more with less, better," states Davis. "We know our future is on the information systems side," Clarke states. "Vendors' investment in the development and creativity of automation is what is going to drive the future of the laboratory." "Implementing the automation solution was absolutely the right thing to do for Sacred Heart Health," says Wright. "With the transition complete, we are pleased with the results. All we want now is more automation that will enable us to do even more with what we have."

根据互联电网区间振荡的特点，可将参与振荡的机群按各自的“部分惯性中心”等值为两机系统。文中首先推导了等值两机系统的电磁转矩系数，为区间振荡模式的电磁转矩分析奠定了理论依据。在此基础上提出了双通道反馈结构的广域电力系统稳定器（PSS），并采用建立在同步转矩及阻尼转矩概念上的扩展相位补偿法，进一步推导了反映广域反馈信号与本地反馈信号之间关系的传递函数，然后进行相量坐标映射变换，最后系统研究了广域PSS的参数设计。仿真结果表明:它能有效抑制系统的区间低频振荡，提高系统的小信号稳定极限，与其他稳定器设计方法相比，能够进一步改善系统阻尼特性。

根据互联电网区间振荡的特点，可将参与振荡的机群按各自的“部分惯性中心”等值为两机系统。文中首先推导了等值两机系统的电磁转矩系数，为区间振荡模式的电磁转矩分析奠定了理论依据。在此基础上提出了双通道反馈结构的广域电力系统稳定器（PSS），并采用建立在同步转矩及阻尼转矩概念上的扩展相位补偿法，进一步推导了反映广域反馈信号与本地反馈信号之间关系的传递函数，然后进行相量坐标映射变换，最后系统研究了广域PSS的参数设计。仿真结果表明:它能有效抑制系统的区间低频振荡，提高系统的小信号稳定极限，与其他稳定器设计方法相比，能够进一步改善系统阻尼特性。

In order to solve instability the interaction among the various DC-modulation and between DC-modulation and PSS in AC/DC system, a chaotic optimization algorithm (COA) is applied to integrated AC/DC hybrid power system in which the multi-infeed DC power transmission system is included, and the research on coordination controls between the HVDC modulations and PSS is investigated in this paper. Parameters tuning problem of the HVDC modulations and PSS is converted to an optimization problem which is solved by a chaotic optimization algorithm based on Lozi map, Thus under global coordination the damping of the whole system to the electromechanical oscillations in the AC system is enhanced. Taking the planned power network in the South Power Grid for example, the effectiveness, robustness and superiority of the presented method are verified.

In order to solve instability the interaction among the various DC-modulation and between DC-modulation and PSS in AC/DC system, a chaotic optimization algorithm (COA) is applied to integrated AC/DC hybrid power system in which the multi-infeed DC power transmission system is included, and the research on coordination controls between the HVDC modulations and PSS is investigated in this paper. Parameters tuning problem of the HVDC modulations and PSS is converted to an optimization problem which is solved by a chaotic optimization algorithm based on Lozi map, Thus under global coordination the damping of the whole system to the electromechanical oscillations in the AC system is enhanced. Taking the planned power network in the South Power Grid for example, the effectiveness, robustness and superiority of the presented method are verified.