Abstract: With the advancement of carbon peaking and carbon neutrality goals, the large-scale integration of wind and photovoltaic power, along with the widespread deployment of flexible DC transmission and electrochemical energy storage, has steadily increased the penetration of power electronic devices, accelerating the transition of power systems toward high power-electronics-density configurations. In this context, interharmonic distortion has become increasingly prominent, characterized by broadband, dense-spectrum, and stochastic features, which pose critical threats to power quality, equipment safety, and system stability. This paper begins with an overview of the fundamental concepts and generation mechanisms of harmonics and interharmonics, followed by a systematic review of recent advances in interharmonic detection methodologies, including time-frequency domain analysis, modern spectral estimation, and machine learning approaches. Furthermore, interharmonic suppression techniques and their underlying mechanisms—such as inverter control optimization, filtering strategies, and protection coordination—are comprehensively summarized. Finally, key bottlenecks in current research and potential directions for future investigation are identified.