Abstract: A method involves receiving power data measurements at nodes of an electrical power grid, the electrical power grid having multiple buses. For a first bus of the electrical power grid, an objective function is repeatedly minimized using the received power data measurements to determine estimated admittances between the first bus and other buses of the electrical power grid. The minimization of the objective function is linearly constrained by a repeatedly estimated sum of conductances and susceptances connected to the first bus. A minimum value of the objective function for the first bus is determined that corresponds to a maximum value of the estimated sum of conductances and susceptances. A topology of the electrical power grid associated with the first bus is determined based on the estimated admittances that correspond to the minimum value of the objective function and to the maximum value of the estimated sum of conductances and susceptances.