Minimizing line energy loss of radial distribution feeder with a PV Distributed Generation unit avoiding reverse power flow

A procedure for minimizing the accumulated line power losses of radial distribution feeder over the day, namely line energy loss, has been developed. It determines the optimal size and location of a Photovoltaic Distributed Generation (PVDG) unit that minimizes the line energy loss, while avoiding reverse power flow along the feeder. The procedure considers the concept that the PVDG production varies independently from the changes in feeder demand, which most likely results in a peak mismatch for both. With such mismatch the PVDG unit can produce only part of its capacity at the time the feeder meets its peak load demand. Hence, the objective of minimizing the line energy loss is more appropriate in this application than that of minimizing the line peak power loss. However, dealing with energy-based quantities needs a sort of calculations for each time interval over the whole daily duration. In this essence a suitable method has been derived to rate the line energy loss of the feeder at only one time interval over the day, namely Feasible Optimization Interval (FOI). The procedure has been applied successfully on two 11kV radial distribution feeders within Abu Dhabi network. The application demonstrated that the optimal solution resulting in minimum line power loss at the FOI is the same resulting in minimum line energy loss over the day.