1.0 Introduction This documentation explains the technical aspects of the Power Flow Module – Sweeping Method Version 1.0, implemented for GridLAB-D. The power flow module provides electrical distribution system modeling for power flow solutions. A power flow calculation is performed to determine what the node voltages and line currents are at each point of the system, given the system model, electrical loads connected at each node, and voltage at the substation. The power flow problem is solved using a three-phase, forward-back sweep method. The specific methodology and equations are described in Kersting (2007). The basic equations are in the following forms: