An efficient model of synchronous generator for hydraulic power plant dynamic simulations

The paper is concerned with practical modelling of the synchronous generator (SG) as the main component of the hydroelectric power plant. The generation system under study comprises the hydraulic circuit, the speed regulator, the excitation system and the SG. Each system component is formatted into state form. The SG state model developed with field voltage as the only controlled input variable and with stator currents, field currents and stator voltages as output observed variables, includes both the saturation phenomenon and the mechanical motion. The resulting flexible SG model connected to other power plant components allows predicting various tests such as: the classical three-phase sudden short-circuit test, the field short-circuit test with the stator in open circuit and the load rejection and line-switching tests. In order to prove the effectiveness of the proposed power plant modeling framework, extensive simulations using the Matlab/Simulink program are performed and discussed for different tests and plant scenarios (automatic voltage regulator (AVR) on and off).