In today’s interconnected power grids, low-frequency oscillations is a significant issue limiting the power transfer capability and even deteriorating power system security due to potential low-damped or even undamped oscillations. Typically, local controllers (e.g., power system stabilizers on generators) have been used to suppress these low-frequency oscillations. Conventionally, these controllers are designed based on the system circuit model around a particular operating point, and tuned for hypothetical critical operating conditions. However, they may not perform as well as expected in some extreme cases due to their limited adaptiveness. Synchronized measurements provided by PMUs enable the design and development of wide-area oscillation damping controllers that are adaptive to the grid’s varying operating conditions to overcome the limitations of traditional controllers.