Time domain dynamic aggregation of generating unit based on structure preserving approach

An important problem associated with transient stability studies for electric power systems in existing digital type simulation program is the use of dynamic equivalent models to represent the dynamic behavior of the systems. Dynamic aggregation thus becomes one of the main steps in constructing a power system dynamic equivalent. This paper presents a time domain dynamic aggregation of power generating units and its control systems by using the structure preserving approach. The dynamic aggregation method has been used to derive the mathematical models of classical synchronous machine, the exciter system, the turbine-governor system, and also the power system stabilizer. The method has also been tested on the practical TNB-EGAT (Tenaga Nasional Berhad-Electric Generating Authority of Thailand) AC-HVDC power system and the simulation results demonstrated a satisfactory match between full power systems and the equivalent system.