10 Variable and Adjustable Speed Generation Systems Włodzimierz Koczara Institute of Control and Industrial Electronics, Warsaw University of Technology, Koszykowa 75 Street 00-662 Warszawa, Poland. Email: Koczara@isep.pw.edu.pl 10.1 Introduction 10.1.1 Conventional Generation Systems Variable speed generation is an emerging technology. At the present time, electrical power systems are based on generation standard AC electricity by Wound Rotor Synchronous Generator (WRSG). Figure 10.1 shows a simple generation power system, where the wound rotor synchronous generator WRSG is driven by a prime mover DE producing torque T d . The WRSG operates with the fixed speed ω gm and supplies a load. The generator produces an opposite torque T g . Figure 10.1. The classical generation system with WRSG