A review of distributed generation technologies and their impact on modern power systems

Globally, there is a significant transformation involving conventional power systems, such transformations are driven by concerns over climate change, energy security, and sustainability. In recent decades, more distributed generation (DG) systems and distributed energy resources (DER) systems have penetrated the conventional power grids, particularly those based on wind and solar technologies. The rapid technological developments of DER systems are largely governed by advancements in power electronics technologies and related fields, which form the core of the characteristics of modern power systems. However, the increasing relevance of DER systems has transformed traditional unidirectional power flow into bidirectional power flow, introducing new challenges to system stability, reliability, and security. As a result, various international standards, grid codes (GCs), and inverter control algorithms that shape key power systems parameters; such as active power/ frequency control (APC/F C ) and reactive power/voltage control (RPC/V C ), are evolving. In addition, emerging concept known as fault ride-through (FRT) capabilities together with modern power electronics-based protection logics are been developed to facilitate secure and reliable integration of DER into modern power grids. The paper reviews the key technical, regulatory, and policy challenges associated with DER integration, including issues related to control algorithms, grid interoperability, and operational flexibility. Furthermore, it presents an overview of power systems supportive functions provided by DER inverters, which are categorized into reactive power/voltage control (RPC), voltage ride-through (VRT), and frequency ride-through (FRT) capabilities. The advantages, limitations, and evolution of these control algorithms and research gaps in both policy challenges and technical challenges are analyzed, along with emerging trends that will continue to shape the future of modern power systems.