EXPERIMENTAL STUDIES ON STABILITY OF POWER SYSTEMS COMPOSED OF MANY DISPERSED POWER SOURCED USING MICRO-MACHINES

为了验证纵向电力系统两端环网互联对系统稳态稳定性影响的仿真结果，并分析含环网的更复杂电力系统的稳态稳定性，我们进行了两年的实验研究。取得的研究成果和今后的研究方向如下：1.稳态稳定模拟器的实验结果：稳态稳定模拟器由极小尺寸的交流发电机、飞轮、直流电动机和传输线电感器构成，并构成纵向电力系统和环形电力系统。稳态稳定性极限进行了测量，每个系统与3机，4机和5机组成。研究表明，无论机器数量多少，环状系统都比纵向系统稳定.含回路复杂电力系统的仿真结果：通过特征值计算分析了一个顶部型电力系统（两端与相邻电力系统相连的回路电力系统）和一个梯形电力系统（多个中间点相互连接的回路电力系统）的稳态稳定性。通过改变联络线的电抗和计算特征值，明确了这类电力系统具有纵向系统和环状系统的特点.未来的研究：在目前的研究中，所有的分散电源都假设为同步发电机。但在实际的电力系统中，存在着许多分散的电源，这些电源将直流输出功率转换成交流电，并与交流电源系统相连。这种电力系统的稳定性进行了分析。

We have for two years done experimental investigation in order to experimentally verify the results of the simulation on the variation of steady-state stability owing to the looped interconnection of longitudinal power systems at the both ends, and to analyze the steady-state stability of more complex power systems including loops. The obtained results and the works to be done in the future are as follows.1. Results of experiments on steady-state stability simulator : The steady-state stability simulator was constructed from extremely small-sized ac generators, fly-wheels, dc motors and transmission line inductors, and longitudinal power systems and looped power systems were constituted. Steady-state stability limits were measured on each system with 3-machine, 4-machine and 5-machine composition. It was ascertained that the looped systems are more stable than the longitudinal systems regardless of the number of machines.2. Results of simulation on complex power systems including loops : Steady-state stability was analyzed by eigenvalue calculation for a top-shaped power system (a looped power system with the both ends interconnected to neighboring power systems) and a ladder-shaped power system (a looped power system with several intermediate points interconnected each other). It was made clear by changing the reactance of the interconnecting lines and calculating the eigenvalues that these power systems possess the characteristics of longitudinal systems and looped systems.3. Studies to be done in the future : In the present studies, all the dispersed power sources are assumed to be a synchronous generator. But in practical power systems, there exist many dispersed power sources, where the dc output power is converted into ac, and interconnected to ac power system. The stability of such power systems is to be analyzed.