A New Model for PV Nodes Using an Efficient Backward/Forward Sweep Power Flow Technique

PV model

Abstract

Most of the distribution networks may to contain reactive power sources like distributed generators with reactive support, static VARs compensators or even switching capacitors. Then it is necessary to have a convenient model for controlled-voltage (PV) nodes to be applied in such conditions. However, this fact presents some challenges when a Backward/Forward Sweep (BFS) power flow formulation is used, some authors proposed hybrid methods, iterative methods, sensitivities matrix- based methods, among others. Unfortunately, these methods usually require complex formulations, therefore, a new and simple methodology is proposed in order to reduce execution times. On the other hand, a power flow analysis is a very important tool for all power systems engineers. The nonlinear methods based on the Newton- Raphson method and its decoupled forms and also the Gauss-Seidel with Ybus factorized method have been popular to nowadays. However, some of these methods have presented convergence problems when are applied to distribution systems analysis. The reasons are the inherent characteristics of distribution networks, such as: high r/x ratios, very low branch impedances, radial feeder configurations, among others. In such a sense, techniques based on BFS methods for power flows have been widely applied in distribution systems. In this paper a very efficient and simple formulation for calculating power flows, called LRSV, is used with the new methodology formulated in order to model PV nodes. Some tests cases are shown to demonstrate the procedure.