MULTIPLE TIME-SCALE POWER-SYSTEM DYNAMIC SIMULATION

Several types of power system performance problems have become increas ingly important due to increased utilization of transmission systems i n stressful situations for which they were not originally designed. Co rrespondingly, analytical methods to predict and design systems under these conditions are needed. Voltage instability and mid- and long-ter m disturbances are two of the most prominent of these problems. A new program, EXSTAB, has been developed to achieve the required capability . The capability includes multiple execution modes and automatic step size selection to address conflicting goals of accuracy and efficiency . The modeling includes a broad range of apparatus to provide the need ed time-scale representation (four orders of magnitude). Modeling for AGC, plant characteristics and control, voltage and reactive power con trol, static and dynamic loads, and protective relaying for apparatus and system connections are all provided. Technologies were developed t o perform analysis of voltage stability and prediction of peak power t ransfer to avoid voltage collapse.