In this paper

we propose a two-stage transmission hardening and planning (TH&P) model that can meet the load growth demand of normal scenarios and the resilience requirements of hurricane-induced damage scenarios. To better measure the resilience requirements

the proposed TH&P model includes two resilience assessment indexes

namely

the load shedding (LS) under the damage scenario and the average connectivity degree (ACD) at different stages. The first-stage model

which aims to meet the load growth demand while minimizing the LS

is formulated as a mixed-integer linear program (MILP) to minimize the total planning and hardening cost of transmission lines

the operating cost of generators

and the penalty cost of wind power and load shedding in both normal and damage scenarios. The second-stage model aims to further improve the ACD when the ACD of the scheme obtained from the first-stage model cannot reach the target. Specifically

the contribution of each transmission line to the ACD is calculated

and the next hardened line is determined to increase the ACD. This process is repeated until the ACD meets the requirements. Case studies of the modified IEEE RTS-24 and two-area IEEE reliability test system-1996 indicate the proposed TH&P model can meet the requirements for both normal and damage scenarios.