Optimal power system steady-state security regions with fuzzy constraints

This paper proposes a new approach to compute the maximal power system steady-state security regions using optimization approach. The maximal steady-state security region-hyperbox-is directly computed through a linear programming (LP) model, in which the upper and lower limits of each component forming a hyperbox are taken as unknown variables, and the objective is to maximize the sum of the generators\´ power adjustment ranges. For the first time, both fuzzy branch power flow constraints and the N-1 security constraints are introduced into the study of the steady-state security regions. A new idea of "N-1 constrained zone" is also adopted to calculate the all N-1 security constraints so as to reduce the computation burden. The steady-state security regions with fuzzy power constraints are successfully calculated on the IEEE 6-bus system.