Amin Khodadadi - Department of Electrical Engineering, Faculty of Engineering, Hormoz Island Branch, Islamic Azad University, Hormoz Island, Iran
Payam Masoodi - Fars Regional Electricity Company

Series capacitors can be used in transmission lines to reduce line impedance and thus improve the dynamic and steady state stability of power system. The series compensation in is one of the best ways to improve abilities of transmission lines. However, this method of compensation can cause an electromechanical coupling between compensated line and turbine-generator system and lead to subsynchronous resonance (SSR). At the moment, using of flexible AC transmission systems (FACTS), such as unified power flow controller (UPFC) is an appropriate solution to improve power system stability. UPFC, not only controls power flow in the network but also is used for both series and parallel compensation without depending on system conditions. In this paper, employment of a supplementary damping controller in UPFC to damp oscillations of SSR is proposed. To achieve this goal, controllability based on singular value decomposition (SVD) concept is used to recognize best inputs of system to apply damping signal. Since, using of classical control include difficulties such as: problems related to dynamic simulation, the non-linearity of the real systems, linearization and associated errors, a neural damping controller will be proposed as a supplementary controller.

Power System Stability, Subsynchronous Resonance, Neural Controller, UPFC