A Flexible Switch for Suppressing Close Loop Damping in Offshore Wind Power Systems

Offshore wind power generation systems can use close loop operation to meet system maintenance requirements and maximize the use of wind resources without disconnecting wind turbines. However, close loop operation with sources can easily cause system damping. This paper analyzes the characteristics of main bus close loop operation and main factors in offshore wind power generation systems. In order to suppress close loop oscillation, a flexible close loop switch that consists main suppressing damping branch, first buffer branch, and second buffer branch is proposed. Based on the characteristics of the close loop operation, the flexible switch closes each branch within the device with a specific time delay to eliminate the close loop damping through changing the close loop resistance. The optimal close loop operation state is achieved through the flexible switch. Finally, a test study of close loop operation in offshore wind power systems is established and analyzed in PLECS simulation software, verifying the effectiveness of the soft close loop device in suppressing close loop operation oscillation.