Bifurcation Point Tracking in Generator Outage Scenario using Nested Holomorphic Embedding Power Flow Method

The power system is operated to an increasing extent bordering its limits. Violation of these limits leads the system towards its bifurcation point (BP), resulting in voltage collapse. Therefore, tracking of BP for generator outage condition is essential, which gives a stability margin to the system operator for preventive control. Hence, a power flow solution, independent of convergence issue is of a great deal. This paper proposes a nested holomorphic embedding power flow method (HEPM) for obtaining power flow solution if one exists along with the bifurcation point and unambiguously notifies its nonexistence under sequential generator outage. It is devoid of the issues faced by iterative methods implemented during major blackouts, cascade failure, and voltage collapse situations. The complexity of the nested HEPM for calculation of the bifurcation point in terms of the number of power flow equations to be solved is extremely lower compared with other iterative methods. The proposed methodology is validated with a modified IEEE 14 bus system using MATLAB in the worst-case scenario where all generators fail except the slack bus.