  This paper develops an efficient algorithm for the multi-period optimal
dispatch of deterministic inverter-interfaced energy storage in an unbalanced
distribution feeder with significant solar PV penetration. The three-phase,
non-convex loss-minimization problem is formulated as a convex second order
cone program (SOCP) for the dispatch of batteries in a receding-horizon fashion
in order to counter against the variable renewable net-load generation. The
solution of the SOCP is used to initialize a nonlinear program (NLP) in order
to ensure a physically realizable solution. The phenomenon of simultaneous
charging and discharging of batteries is rigorously analyzed and conditions are
derived that guarantee it is avoided. Simulation scenarios are implemented with
GridLab-D for the IEEE-13 and IEEE-123node test feeders and illustrate not only
AC feasibility of the solution, but also near-optimal performance and
solve-times within a minute.
