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

独立电力生产商参与自由电力市场将导致电力系统的不安全运行状况，如不可预见的潮流分布，其中故障的影响会蔓延到整个系统。在我们的研究项目中，为了防止这种影响的蔓延，我们研究了基于同步测量技术的电力系统稳定性实时评估。通过该项目获得的结果如下：1。在电力系统动力学辨识和特征分析的基础上，提出了一种估计电力系统主要振荡模态频率和阻尼因子的新方法。同步测量所有发电机的转子角度和转速以及负载偏差，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，对所开发方法的有效性进行了评价。从转子角度和转速的角度出发，根据发电机对慢振荡的相干性，提出了一种适合弱阻尼慢振荡检测的发电机选择方法。3 .通过对部署在日本东北电力系统的GPS同步测量系统所获得的现场数据的调查，阐明了从潮流波动中估计随机负荷偏差的随机性。为了实时识别电力系统动态，研制了一个由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激烈的电力市场潮流管理中的应用。用户协同系统是为了改善包括多个分散发电机在内的配电网的电压分布而提出的一种新的电力需求侧管理方法。

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.