The decades-old traditional power system is undergoing a fast transition with the most prominent feature, i.e., high penetration of renewables and power electronics. The dual high-penetration aspect of a modern power system not only significantly influences the classical system stability issues but also introduces new types of instabilities. This talk first reviews the impacts of the high penetration of renewables and power electronics on power system stability. Then, it focuses on the emerging electromagnetic wideband oscillations. Actual oscillation events reported around the world are summarized. The challenges to the analysis and control of wideband oscillations are discussed. Some research results from the presenter’s group including, e.g, impedance network modeling and analysis, generator- and grid-side damping control, will also be introduced.