Application of flywheel energy storage to damp power system oscillations

Flywheel energy storage system (FESS) is believed to be a potential solution for power quality improvements. This paper proposed a new idea of using a large-mass varying-speed flywheel as an energy storage element to damping power system electromechanical oscillations. In the paper, the FESS is studied in the context of a single-machine infinite-bus (SMIB) power system. The mathematical model of the SMIB power system including a FESS is established, and the Phillips-Heffron control structure of the power system is described. Based on the principle of the complex torque coefficient (CTC) method, the expression of the complex electromagnetic torque of the entire power system including the FESS unit is derived. A 10 kW prototype of FESS, which consists of a double-fed induction machine (DFIM) and a voltage-source pulse width modulation (PWM) rectifier-inverter used as an AC exciter, is developed. Simulation and experiment results demonstrate that it is effective in damping the power system oscillations.