A real-time PMU-based optimal operation strategy for active and reactive power sources in smart distribution systems

Emerging of distributed generation (DG) and automation technologies have changed the nature of distribution systems. In modern smart distribution networks, the use of controllable (dispatchable) and renewable DGs and their optimal management is an attractive solution to meet the load growth. Regarding variability of network topology as well as variations of load demand and renewable DGs' output power, it is vital to schedule controllable DGs in an on-line manner. In this paper, a new, simple, and accurate approach is proposed for optimal on-line management of DG units based on using only one distribution phasor measurement unit (DPMU) for each dispatchable DG. The method does not require network topology, electrical parameters, and power flow results. For this aim, the impedance between DG's connection point and the beginning of the feeder is estimated at first. Then, by using the estimated impedance as well as voltage magnitude and angle of the connection point measured by the DPMU, optimal generation of DG is calculated in order to have minimum power losses. The developed method has been applied to IEEE 33 system, and the simulation results are analyzed. The simulations show that the impedance estimation error of the proposed approach is less than 0.2%. Also, compared to the previous studies, the presented method reaches almost to the same power loss reported in literature with 5.5% saving in the DG size.