The technical studies for grid integration of the 720 MW offshore wind farms around area of Koh Tao
and Koh Pha-Ngan were carried out. The possible connection points for three offshore wind farms under
115-kV of PEA grid were considered. The simulation results on the power flow analysis show that the
suitable maximum capacity of the offshore wind farms for integrating to this system based on the required
conditions is about 432 MWs or 60% of the proposed capacity. With the reduction capacity, the four case
studies of connected points were selected. For all case studies, none of transmission lines has percentage
of load higher than 80%. Moreover, the grid loss of the system decreases, except in the case study 12 and
16, the grid loss increases. Additionally, the region of voltage stability increases both peak load and offpeak
load after integrating offshore wind farms to the grid. Therefore, by studying the power flow and the
voltage stability, the suitable interconnection points for the three offshore wind farms are the case study 6
and 8 because they have percentage of load in the transmission lines under PEA grid connection
requirements, do not increase grid loss, and increase the voltage stability, but the distance of the
transmission line in the case study 6 is longer than that the case study 8. Our results may be used as a
reference to develop an offshore wind farm in the Gulf of Thailand in the future.