Because of different characteristic features of distribution networks, such as radial structure and high R/X ratio, distribution system load flow analysis differs significantly from transmission systems. Accordingly, a number of methods that are specially designed for the solution of the power flow problem in radial distribution systems are found in the literature. Most of the developed methods are based on the forward/backward sweep processes for the solution of the ladder networks. In this article, various distribution system load flow algorithms, based on the forward/backward sweeps, are reviewed, and their convergence ability is quantitatively evaluated for different loading conditions, R/X ratios, and sub-station voltage levels. Moreover, the effects of static load modeling on the convergence characteristics of algorithms are also investigated.

Energy storage systems (ESSs) and demand-side management (DSM) strategies have significant potential in providing flexibility for renewable-based distribution networks. Therefore, combining ESSs and DSM strategies with renewable energy sources (RESs) to solve economic, operational, environmental, and power-related political issues has received special attention from power system planners around the world. In this regard, developed countries, which are pioneers in renewable technologies, have proposed various supportive policies and practices for the widespread use of ESSs and DSM strategies in the context of distribution networks. Hence, this paper performs a comprehensive review of the most recent actions taken to build the infrastructure necessary to achieve 100% renewable energy. On this basis, this paper firstly surveys the necessity of using ESSs and DSM strategies in renewable-based distribution networks. Then, the existing policies and incentive programs implemented in different countries for the development of RESs in optimal coordination with ESSs and DSM strategies are presented. The impacts of utilizing ESSs and DSM strategies in improving the economic performance of the renewable-based distribution networks are also investigated. Finally, prevalent energy management strategies, which are proposed to optimize utilization of ESSs and DSM strategies in renewable-based distribution networks, are investigated from the perspective of optimization approaches.

This paper presents a voltage stability index for identifying the most sensitive bus to the voltage collapse in the radial distribution networks. The developed index is based on the transferred active and reactive power of the distribution line. The performance of the index is tested on different loading conditions for different load models and different substation voltage levels. Results suggest that the proposed index is reliable and can easily be applied to the radial distribution networks.