There is a global focus on adding renewable energy sources to the mix of energy supplies. In this study, the grid connections for large-scale offshore wind farms in areas that have high penetration of renewable energy sources were examined. System strength evaluation considering the interaction of wind farms and inverter-based resources (IBRs) was performed; the fault current was then analyzed to determine their contribution to the total fault current at a bus level. These studies revealed that the interaction between offshore wind farms and IBRs may make the power system weaker, and it is possible that fault current contributions from offshore wind farms can violate the capacity limit of existing circuit breakers. The results of steady-state analysis were verified through case studies focused on the southwest area of the Korea Electric Power Corporation (KEPCO) system where large-scale offshore wind farms are planned to be established and connected. Power system planners will benefit from the results of this study with a better understanding of the factors to consider when integrating large-scale wind farms in areas with high penetration of renewables.