Bi-level framework for cost effective robustness and responsiveness to enhance infrastructure resilience of transmission network against cyclones

Power system transmission infrastructures are becoming vulnerable to the adverse effects of High Impact Low Probability (HILP) events such as the extreme weather conditions leading to their structural damage and prolonged outages. This requires more attention for making a robust and resilient power grid. This paper proposes a bi-level framework for quantitative assessment of resilience of transmission lines using different resilience metrics based on the multi-state resilience curve when the system subjected to severe cyclonic events of different intensities. The system is divided into high, medium, and low wind speed regions observed during a given cyclone. These regions are mapped over the fragility curves of the transmission lines to obtain their failure probabilities using Monte Carlo Simulation (MCS). The robustness and responsiveness of transmission line infrastructure is estimated to determine enhanced ability of the transmission line to withstand and recover from such events. Different economic metrics and costs are proposed for estimated robustness and responsiveness. Sensitivity analysis is performed for economic viability of proposed hardening parameters to enhance the infrastructural resilience. The proposed methodology is investigated on transmission networks resilience studies on IEEE 57 bus system to understand the impact of such catastrophic events during planning stage. Results show that resilience metrics such as Load Not Served (LNS) and Energy Not Served (ENS) have decreased with proposed robustness levels for improved structural hardening. The economic benefits have resulted in reduction of total failure cost by over 35 % with 10 % increase in robustness and nearly 68 % with 20 % robustness respectively.