This document discusses the impact of Flexible AC Transmission System (FACTS) devices on electrical power systems. It analyzes the capabilities of three FACTS devices - Static Var Compensator (SVC), Thyristor Controlled Series Capacitor (TCSC), and Unified Power Flow Controller (UPFC) - with respect to disturbances on the system. Simulations are conducted to analyze the impact of these devices on power flow and Power Oscillation Damping using different control signal choices. The effect of linear and non-linear control signals is shown. Each device's individual impact is considered, followed by a comparative study between them.