An architecture for voltage stability constrained optimal power flow using convex semi-definite programming

In this paper, a new voltage stability constrained optimal power flow (VSC-OPF) architecture is developed using semi-definite programming (SDP) which optimally calculate the loading margin and the cost of increasing stability margins. The main advantages of the proposed method are: a) it incorporates voltage stability constraints in a convex OPF formulation, b) always finds the optimal solution in comparison with probable local optimum solutions while using other non-convex methods, and c) evaluates the cost of increasing the loading margin using convex relaxation. The effectiveness of this method is evaluated using IEEE 14-bus and IEEE 57-bus test systems, considering various network constraints. The results show the effectiveness of proposed convex formulation to find the optimal operating schedule and critical loading point. The effect of incorporating voltage stability margin on the operating cost is also examined using different convex VSC-OPF formulations.