The increasing use of dispersed energy supplies, industrial automation, and nonlinear loads have made Power Quality (PQ) a major problem for utility systems. Voltage sags, swells, flickers, harmonics, and transients are caused by these disturbances, which impair system performance and end-user dependability. This paper presents a comprehensive examination looking into the origins and effects of PQ disruptions, as well as the mitigation measures used to ensure grid stability and compliance with PQ requirements. Each method is evaluated according to its response time, ability to rectify certain disturbances, and appropriateness for integration into the grid infrastructure. The review further highlights recent developments in power electronic converter topologies and modulation techniques that enhance PQ performance under dynamic grid conditions. This review serves as a foundational resource to optimize grid reliability, improve operational resilience, and ensure adherence to internationally recognized PQ standards.