Decentralized voltage control of wind farm based on gradient projection method

A decentralized voltage control (DVC) scheme based on the gradient projection (GP) method is proposed for the wind farm (WF). The wind farm controller optimizes the reactive power output of doubly-fed induction generator (DFIG)-based wind turbines (WTs) and static synchronous compensator (STATCOM) at the medium voltage (MV) side of the step-up transformer. The aim is to keep voltages of all buses in the wind farm within the feasible range and maintain a certain reactive power margin for WTs. The solution method based on the GP method is developed to solve the voltage control optimization problem in a decentralized manner without a central controller or communication between local controllers, which achieves optimal voltage control and greatly saves communication costs. A WF with 1 STATCOM and 40 wind turbine generators (WTGs) was used to validate the control performance of the proposed DVC scheme. The case study results demonstrate that the proposed decentralized voltage control can achieve optimal voltage control without the central controller or communication between local controllers under both normal operation and disturbances.