Distributed power-generation systems (DPGS) contribute significantly to the power generation in modern power systems. Wind and solar photovoltaics (PVs), as representative renewable energy sources, are two major resources for DPGSs. However, owing to their inherent characteristics, the large-scale adoption of DPGSs poses challenges. To resolve these issues and leverage renewable-energy DPGSs, this paper presents DPGS technologies based on wind and solar PVs, as well as their impacts on the distributed grid. Moreover, schemes for enhancing the integration and connection of DPGSs are introduced, and protection issues are discussed in order to increase the robustness of the connection.ABSTRACT | Continuously expanding deployments of distributed power-generation systems (DPGSs) are transforming the conventional centralized power grid into a mixed distributed electrical network. The modern power grid requires flexible energy utilization but presents challenges in the case of a high penetration degree of renewable energy, among which wind and solar photovoltaics are typical sources. The integration level of the DPGS into the grid plays a critical role in developing sustainable and resilient power systems, especially with highly intermittent renewable energy resources. To address the challenging issues and, more importantly, to leverage the energy generation, stringent demands from both utility operators and consumers have been imposed on the DPGS. Furthermore, as the core of energy conversion, numerous power electronic converters employing advanced control techniques have been developed for the DPGS to consolidate the integration. In light of the above, this paper reviews the power-conversion and control technologies used for DPGSs. The impacts of the DPGS on the distributed grid are also examined, and more importantly, strategies for enhancing the connection and protection of the DPGS are discussed.