In wide area backup protection of electric power systems, the prerequisite of protection device's accurate, fast and reliable performance is its corresponding fault type and fault location can be discriminated qui...In wide area backup protection of electric power systems, the prerequisite of protection device's accurate, fast and reliable performance is its corresponding fault type and fault location can be discriminated quickly and defined exactly. In our study, global information will be introduced into the backup protection system. By analyzing and computing real-time PMU measurements, basing on cluster analysis theory, we are using mainly hierarchical cluster analysis to search after the statistical laws of electrical quantities' marked changes. Then we carry out fast and exact detection of fault components and fault sections, and finally accomplish fault isolation. The facts show that the fault detection of fault component (fault section) can be performed successfully by hierarchical cluster analysis and calculation. The results of hierarchical cluster analysis are accurate and reliable, and the dendrograms of hierarchical cluster analysis are in intuition.展开更多
A method is proposed to monitor and control Hopf bifurcations in multi-machine power systems using the information from wide area measurement systems (WAMSs). The power method (PM) is adopted to compute the pair of co...A method is proposed to monitor and control Hopf bifurcations in multi-machine power systems using the information from wide area measurement systems (WAMSs). The power method (PM) is adopted to compute the pair of conjugate eigenvalues with the algebraically largest real part and the corresponding eigenvectors of the Jacobian matrix of a power system. The distance between the current equilibrium point and the Hopf bifurcation set can be monitored dynamically by computing the pair of con- jugate eigenvalues. When the current equilibrium point is close to the Hopf bifurcation set, the approximate normal vector to the Hopf bifurcation set is computed and used as a direction to regulate control parameters to avoid a Hopf bifurcation in the power system described by differential algebraic equations (DAEs). The validity of the proposed method is demonstrated by regulating the reactive power loads in a 14-bus power system.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
针对越来越多的研究利用由广域测量系统(wide area measurement system,WAMS)和监控及数据采集系统(supervisory control and data acquisition,SCADA)组成的混合测量来改善传统状态估计的情况,在分析WAMS/SCADA混合测量数据兼容性的基...针对越来越多的研究利用由广域测量系统(wide area measurement system,WAMS)和监控及数据采集系统(supervisory control and data acquisition,SCADA)组成的混合测量来改善传统状态估计的情况,在分析WAMS/SCADA混合测量数据兼容性的基础上,提出一种可行的兼容方案解决混合测量的数据兼容问题。研究从WAMS和SCADA的数据差异入手,建立混合测量模型,分析得出2种数据的时间同步性和测量权值为影响混合测量数据兼容的主要因素,进而提出兼容方案,实现WAMS和SCADA数据的同步,并重新量化测量权值。在标准测试系统上的仿真验证了关于WAMS/SCADA混合测量状态估计数据兼容性分析的正确性和兼容方案的有效性。展开更多
目前,电力系统低频振荡诊断与分析中面临的主要困难是如何利用有限的广域量测系统(wide area measurementsystem,WAMS)数据快速准确的识别振荡源。针对此问题,提出一种基于WAMS信息构建电网割集计算振荡能量的实用方案。首先定义了割集...目前,电力系统低频振荡诊断与分析中面临的主要困难是如何利用有限的广域量测系统(wide area measurementsystem,WAMS)数据快速准确的识别振荡源。针对此问题,提出一种基于WAMS信息构建电网割集计算振荡能量的实用方案。首先定义了割集振荡能量的概念与计算方法,并提出基于关键线路的WAMS动态信息可构建不同层次的网络割集,其中振荡能量流出的割集即可判断为振荡源。最后,通过在实际电网中仿真和对三峡电厂某次振荡实例的分析,验证了该方法的有效性。案例分析结果表明,割集能量的方法可以最大限度地利用WAMS信息,直观快速地显现电网振荡时的特征,摆脱对元件参数精确性的依赖,快速定位振荡区域,有效识别振荡源。展开更多
鉴于相量测量单元(phasor measurement unit,PMU)能够实时测量母线电压和相角,在传统监控和数据采集(supervisory control and data acquisition,SCADA)量测系统的基础上,提出了一种选择PMU最优配置方案的新方法。该法在假定系统完全可...鉴于相量测量单元(phasor measurement unit,PMU)能够实时测量母线电压和相角,在传统监控和数据采集(supervisory control and data acquisition,SCADA)量测系统的基础上,提出了一种选择PMU最优配置方案的新方法。该法在假定系统完全可观测的前提条件下,考虑不同量测噪声信号比的影响,采用直接替代(direct sub-stitution,DS)法、加权最小二乘(weighted least squares,WLS)法和扩展加权最小二乘(augmented weighted least squares,AWLS)法计算状态估计值,验证了量测噪声对选择PMU配置点没有影响这一结论,并最大限度地提高了状态估计的准确度。在IEEE9节点和IEEE14节点测试系统上验证了此方法的正确性和有效性。展开更多
2008年冰灾期间,华中电网广域测量系统(wide area measure system,WAMS)多次记录到低频振荡事件。文中以1月21日03:31:39WAMS实测的典型区域低频振荡事件为例,利用电力系统分析综合程序6.25对其进行了仿真分析,通过频域和时域稳定计算...2008年冰灾期间,华中电网广域测量系统(wide area measure system,WAMS)多次记录到低频振荡事件。文中以1月21日03:31:39WAMS实测的典型区域低频振荡事件为例,利用电力系统分析综合程序6.25对其进行了仿真分析,通过频域和时域稳定计算对其进行了重现。结合选定的能量管理系统、WAMS实测运行方式及其录波数据,对潮流电压及低频振荡的静态和动态特性进行了仿真,分析了低频振荡产生的原因、振荡特点及其抑制措施,为华中电网的生产运行和发展规划提供了参考,同时对有关静态及动态模型参数和计算工具的工程可信度进行了校核,为电力系统的仿真计算提供了借鉴。展开更多
由于电力系统的动态特性,由广域测量系统(wide area measurement system,WAMS)/数据采集与监视控制(supervisory control and data acquisition,SCADA)系统收集来的量测信息不可避免地存在粗量测误差、系统状态突变等各种异常情况。针...由于电力系统的动态特性,由广域测量系统(wide area measurement system,WAMS)/数据采集与监视控制(supervisory control and data acquisition,SCADA)系统收集来的量测信息不可避免地存在粗量测误差、系统状态突变等各种异常情况。针对这一问题,提出一种采用自适应动态状态估计器的并能有效检测、辨识和排除WAMS/SCADA系统中异常情况的信息校正算法。该算法依据动态状态估计器预测系统状态的能力,利用标准化新息以及加权新息与标准化新息的最大比值来检测和辨识多个坏数据、负荷突变、网络拓扑结构错误以及这3种异常同时发生的情况,并利用标准化新息和残差来验证异常处理的效果。数值结果表明所提算法能够快速、准确、有效地检测、辨识和排除动态状态估计过程中的各种异常情况。展开更多
文摘In wide area backup protection of electric power systems, the prerequisite of protection device's accurate, fast and reliable performance is its corresponding fault type and fault location can be discriminated quickly and defined exactly. In our study, global information will be introduced into the backup protection system. By analyzing and computing real-time PMU measurements, basing on cluster analysis theory, we are using mainly hierarchical cluster analysis to search after the statistical laws of electrical quantities' marked changes. Then we carry out fast and exact detection of fault components and fault sections, and finally accomplish fault isolation. The facts show that the fault detection of fault component (fault section) can be performed successfully by hierarchical cluster analysis and calculation. The results of hierarchical cluster analysis are accurate and reliable, and the dendrograms of hierarchical cluster analysis are in intuition.
基金the National Natural Science Foundation of China (Nos. 50595414 and 50507018)the National Key Technolo-gies Supporting Program of China during the 11th Five-Year Plan Period (No. 2006BAA02A01)the Key Grant Project of MOE, China (No. 305008)
文摘A method is proposed to monitor and control Hopf bifurcations in multi-machine power systems using the information from wide area measurement systems (WAMSs). The power method (PM) is adopted to compute the pair of conjugate eigenvalues with the algebraically largest real part and the corresponding eigenvectors of the Jacobian matrix of a power system. The distance between the current equilibrium point and the Hopf bifurcation set can be monitored dynamically by computing the pair of con- jugate eigenvalues. When the current equilibrium point is close to the Hopf bifurcation set, the approximate normal vector to the Hopf bifurcation set is computed and used as a direction to regulate control parameters to avoid a Hopf bifurcation in the power system described by differential algebraic equations (DAEs). The validity of the proposed method is demonstrated by regulating the reactive power loads in a 14-bus power system.
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.
文摘针对越来越多的研究利用由广域测量系统(wide area measurement system,WAMS)和监控及数据采集系统(supervisory control and data acquisition,SCADA)组成的混合测量来改善传统状态估计的情况,在分析WAMS/SCADA混合测量数据兼容性的基础上,提出一种可行的兼容方案解决混合测量的数据兼容问题。研究从WAMS和SCADA的数据差异入手,建立混合测量模型,分析得出2种数据的时间同步性和测量权值为影响混合测量数据兼容的主要因素,进而提出兼容方案,实现WAMS和SCADA数据的同步,并重新量化测量权值。在标准测试系统上的仿真验证了关于WAMS/SCADA混合测量状态估计数据兼容性分析的正确性和兼容方案的有效性。
文摘目前,电力系统低频振荡诊断与分析中面临的主要困难是如何利用有限的广域量测系统(wide area measurementsystem,WAMS)数据快速准确的识别振荡源。针对此问题,提出一种基于WAMS信息构建电网割集计算振荡能量的实用方案。首先定义了割集振荡能量的概念与计算方法,并提出基于关键线路的WAMS动态信息可构建不同层次的网络割集,其中振荡能量流出的割集即可判断为振荡源。最后,通过在实际电网中仿真和对三峡电厂某次振荡实例的分析,验证了该方法的有效性。案例分析结果表明,割集能量的方法可以最大限度地利用WAMS信息,直观快速地显现电网振荡时的特征,摆脱对元件参数精确性的依赖,快速定位振荡区域,有效识别振荡源。
文摘鉴于相量测量单元(phasor measurement unit,PMU)能够实时测量母线电压和相角,在传统监控和数据采集(supervisory control and data acquisition,SCADA)量测系统的基础上,提出了一种选择PMU最优配置方案的新方法。该法在假定系统完全可观测的前提条件下,考虑不同量测噪声信号比的影响,采用直接替代(direct sub-stitution,DS)法、加权最小二乘(weighted least squares,WLS)法和扩展加权最小二乘(augmented weighted least squares,AWLS)法计算状态估计值,验证了量测噪声对选择PMU配置点没有影响这一结论,并最大限度地提高了状态估计的准确度。在IEEE9节点和IEEE14节点测试系统上验证了此方法的正确性和有效性。
文摘2008年冰灾期间,华中电网广域测量系统(wide area measure system,WAMS)多次记录到低频振荡事件。文中以1月21日03:31:39WAMS实测的典型区域低频振荡事件为例,利用电力系统分析综合程序6.25对其进行了仿真分析,通过频域和时域稳定计算对其进行了重现。结合选定的能量管理系统、WAMS实测运行方式及其录波数据,对潮流电压及低频振荡的静态和动态特性进行了仿真,分析了低频振荡产生的原因、振荡特点及其抑制措施,为华中电网的生产运行和发展规划提供了参考,同时对有关静态及动态模型参数和计算工具的工程可信度进行了校核,为电力系统的仿真计算提供了借鉴。
文摘由于电力系统的动态特性,由广域测量系统(wide area measurement system,WAMS)/数据采集与监视控制(supervisory control and data acquisition,SCADA)系统收集来的量测信息不可避免地存在粗量测误差、系统状态突变等各种异常情况。针对这一问题,提出一种采用自适应动态状态估计器的并能有效检测、辨识和排除WAMS/SCADA系统中异常情况的信息校正算法。该算法依据动态状态估计器预测系统状态的能力,利用标准化新息以及加权新息与标准化新息的最大比值来检测和辨识多个坏数据、负荷突变、网络拓扑结构错误以及这3种异常同时发生的情况,并利用标准化新息和残差来验证异常处理的效果。数值结果表明所提算法能够快速、准确、有效地检测、辨识和排除动态状态估计过程中的各种异常情况。
