Real Time Identification and Stability Assessment of Electric Power Systems By Synchronized Measurement

独立发电商参与电力自由市场将导致电力系统不安全的运行条件，例如不可预见的潮流分布，其中故障的影响扩散到整个系统。为了防止这种影响的扩散，本课题研究了基于同步测量技术的电力系统稳定性实时评估方法。通过该项目取得的成果如下：1.提出了一种基于电力系统动态辨识和系统特征分析的电力系统主要振荡模式频率和阻尼因子估计方法。所有发电机的转子角度、转速和负载偏差的同步测量用于系统辨识。通过对东北电力公司电力系统模型的仿真研究，对所提出的方法的有效性进行了评估。提出了一种基于发电机与慢振荡相关性的新方法，从转子角度和转速选择适合于检测弱阻尼慢振荡的发电机。通过对部署在日本东北电网的基于GPS的同步测量系统获得的现场数据的调查，明确了随机负荷偏差的随机特性可以从潮流波动中估计出来。为了实现电力系统动态参数的实时辨识，开发了由14台PC机和局域网组成的并行计算系统。利用该计算系统，阐明了移动代理在竞争电力市场潮流管理中的应用。客户协作系统作为一种新的电力需求侧管理方法，是为了改善含有多台分散电源的配电网的电压分布而提出的。

The participation of independent power producers into free markets of electricity will cause insecure operating conditions of a power system such as unforeseeable power flow profiles where the effects of a fault spread over the whole system. In our research project, in order to prevent such effects from spreading, real time assessment of power system stability based on synchronized measurement technology has been studied. The results obtained through the project are as follows.1. A novel method to estimate modal frequencies and damping factors of major power oscillations was developed which is based on identification of power system dynamics and eigenanalysis of the identified system. The synchronized measurements of rotor angles and speeds of all generators and load deviations are used for the system identification. The effectiveness of the developed method was evaluated through simulation studies of the power system model used by Tohoku Electric Power Company.2. A new method to select the generators suitable for the detection of weakly damped slow oscillations from the rotor angles and speeds was developed which is based on coherency of generators with respect to the slow oscillations.3. Through the investigation of the field data that were obtained by the GPS based synchronized measurement system deployed over the northeast power system in Japan, it was clarified that the stochastic properties of random load deviations can be estimated from power flow fluctuations.4. In order to identify power system dynamics in real time, a parallel computing system, which consists of fourteen PCs and LAN, was developed. By utilizing the computing system, application of mobile agent to power flow management in competitive electricity markets was clarified.5. As a new approach for DSM, Customer's Cooperation System was proposed in order to improve voltage profile of distribution networks including many dispersed generators.