A New Power Flow Algorithm for Passive and Active Radial Distribution Networks

Abstract

Due to the rapid increase in electricity consumption, there is a tendency to install distributed generations (DGs) at the level of distribution systems. Therefore, the distribution systems become active, and special load flow methods have to be developed and applied due to its radial structure and the relatively high ratio of resistance to reactance components. This paper presents a new forward algorithm for balanced three-phase load-flow analysis of radial distribution networks (RDNs). Kirchhoff’s Current Law and Kirchhoff’s Voltage Law are utilized. However, a new arrangement of these equations is presented based on formation of virtual slack buses and subsystems truncated from the original network during iteration. The proposed algorithm firstly applied on three IEEE benchmark RDNs with different cases such as different load models, various loading levels to illustrate the convergence even high loading, and inserted DGs,; then it is applied on a real system in Egypt. Its high convergence rate is tested for the DG optimization problem. Further, the virtual subsystems can be utilized to recognize quickly the effect of load changes on the bus voltage profile. The results show that the proposed algorithm is more accurate, not sensitive to initial value, simple equations are used, and robust with high convergence rate because of employing the updated bus voltages immediately after determining their value.