Day-ahead dispatch rescheduling for congestion mitigation under optimal power flow

In this paper the problem of congestion management in the power grid under the application of the day-ahead dispatch schedule, is faced based on developing a day-ahead guideline regarding the required modifications to the power units' output to yield a more uniform loading to the grid's lines. These modifications result by comparing the dispatch schedule provided by an optimal power flow (OPF) analysis for the grid, under the objective function of power loss minimization, with the schedule for the day-ahead dispatch schedule. The point here is that the solution for the latter approach is based on an economical perspective while the former one on a technical one. The proposed approach is tested on the benchmarked 118 bus system which was modified to simulate the Greek transmission network. The day-ahead schedule is initially applied on the system to depict possible congestion issues via a power flow (PF) analysis. Then, an OPF analysis is applied in order to reschedule the power output of the power units, within their operational limits, aiming at power loss minimization. The results indicate that congestion mitigation in terms of lines' loading below their thermal limit could result under proper and guided alterations for the power units output.