Studies on Stability Monitoring and Control System for Synchronous Generators by ASPAC

本研究的目的是开发一种新型的电力系统同步电机微机在线稳定监测与控制系统。ASPAC是我们为监测和改善稳态稳定性而开发的一种新的、独特的方法，它用气隙磁链和转矩来表示稳定性，而不是用已经广泛使用但物理意义有些模糊的电机终端条件。基于ASPAC的概念，提出了一种利用ASPAC在线测量的气隙磁链、转速等数据计算动态稳定性指标的新方法。通过在ASPAC系统中增加该功能，设计了一种新的稳定监控系统。该系统由微机ASPAC和PC-9801-VX-41微机组成，每隔一定时间测量并存储有关发电机的气隙磁通、机端电压、电枢电流、负荷角、转子转速、励磁电流等参数。ASPAC还具有以下功能：数字自动电压调节器（AVR）和数据记录。前者用于自动AVR增益和时间常数控制，后者用于离线数据分析。在电力系统每次发生扰动时，微机利用ASPAC的数据计算出同步转矩系数ks和阻尼转矩系数K_D，并在电视屏幕上显示它们的变化。实验和分析证实，所开发的系统在我们实验室的一台机器和两台机器连接到一个无限gus系统工作良好。该系统的计算结果与大型计算机的离线计算结果吻合得很好。希望今后能进一步提高计算精度，特别是kd的计算精度，并进一步提高计算时间。

The purpose of this study is to develop a new microcomputer-based on-line stability monitoring and control system for synchronous machines in electric power systems. ASPAC, which was developed by us for the monitoring and improvement of steady-state stability, was quite new and unique in that it used airgap fluxes and torque for the expression of stability instead of machine's terminal conditions that had been used widely but somewhat vague in physical meaning. Based on the ASPAC concepts, a new method to calculate a dynamic stability index by using the on-line data such as airgap flux, rotor speed and so on obtained by ASPAC was developed. By adding this function to ASPAC, a new stability monitoring and control system was disigned. The newly-developed system consists of a microprocessor-based aspac and a personal computer (PC9801-VX41).The ASPAC measures airgap flux, terminal voltage, armature current, load angle, rotor speed, field current and so on of the generator concerned at appropriate time intervals and stores them. The ASPAC also has the following functions: the digital automatic voltage regulator (AVR) and the data logging. The former is used for automatic AVR gain and time-constant control and the latter is used for off-line data analysis. The personal computer calculates both the synchronizing torque coefficient ks and the damping torque coefficient K_D, using the data from ASPAC, every time the disturbance occurs in the electric power system, and displays the transition of them on tv screen. It is confirmed experimentally as well as analytically that the developed system works well for both one-machine and two-machine connected to an infinite-gus system in our laboratory. The results obtained by the developed system agrees very well with the computed balues by a large-scale computer off-line. It is desirable that the computing accuracy, especially for kd, and the thole computing times are improved in the future.