  In this paper, we propose a planning method for large-scale offshore wind
farm (OWF) electrical collector system (ECS) based on mixed integer linear
programming, in which the sizing and siting of offshore substations and the
lines between wind turbines (WTs) are optimized. We found out that the problem
is similar to power distribution system planning, where the topological
constraints for distribution network expansion planning (DNEP) are applied to
guarantee the radiality of ECS topology and accelerate the solving process.
Case studies based on an OWF with 63 fixed-locations WTs demonstrate the
effectiveness of proposed method, in which the cost of ECS's investment on
cables is reduced by 23%, power loss reduced by 44% compared with a
conventional design, and the calculation time reduced with the help of the
radiality constraint.
