Distribution power systems are evolving due to the incorporation of emerging technologies such as intelligent electronic devices, smart inverters and distributed energy resources requiring distribution engineers to have access to power system analysis tools that support the changing design and time-based features of such systems. The power system analysis tools should harmonize the new technologies in a way that autonomous and interconnected systems can be automated, simultaneously operated and visualized for maximum grid benefit by distribution engineers.Classic analysis based on static snapshots of loading is an inadequate practice for scheduling future investments in distribution systems and distribution management systems. This is a common practice that has been used for decades to maintain power systems over time. However, the needs of future systems require the integration of modern computing technologies and interfaces with advanced distribution system analysis. This accelerates the analysis and providing to the distribution engineer the information to make the right choice.In this paper, we discuss the needs mentioned above, and propose a flexible framework to support the development of distribution systems analysis. This multidisciplinary framework is supported by a set of open source tools developed by EPRI and other parties for presenting a modular approach to enable the next generation of distribution system analysis tools. These tools have been developed to advance the capabilities EPRI's Open Source Distribution System Simulator OpenDSS to guide the industry on the distribution power system analysis tools and techniques.