Optimal power flow: a tool for managing the transmission congestion

This paper presents a study of the Lagrange multipliers in congested transmission systems. The Lagrange multiplier indicates the sensitivity of constraints related with the objective function. The Lagrange multipliers are obtained via optimal power flow with transmission constraints. Optimal power flow problem is solved by primal-dual logarithmic barrier method. The results obtained in networks (53 and 118 bus) show that the proposed technique is able to improve system planning.