Design of a multilevel control strategy for integration of stand-alone wind/diesel system

Control of variable speed wind turbines coupled with squirrel cage induction generators situated in remote areas is difficult and suffers from some fundamental problems. These systems cannot stabilize frequency and voltage of the grid in acceptable ranges. Changes in the load during 1 day and sudden changes in wind speed also make this problem harder to deal with. In this paper, a system consisting of three wind turbines integrated with two types of diesel generator connected to a variable load is analyzed, and a new multilevel control strategy is proposed. A new load model is implemented by changing power demand based on load curve. This control method adjusts a controller based on past system and environmental data. Simulations based on PSCAD/EMTDC software show the ability of the proposed control system to provide high quality power for this type of load.

► In this study wind, wind turbines, diesel-generators and a variable load are modeled.
► The control strategy consists of three control levels.
► It consists of prediction and planner unit, intermediate level and local controls.
► The trust idea is proposed and applied in the strategy of control.
► It is concluded that the controller controls the system with less complexity.