Grid-Connected Adaptive Analysis and Control of the DC Wind Turbine Under the Grid-Side Transient Faults

The grid-side transient fault ride-through problem seriously affects the stable operation of the grid-connected wind turbine. At present, the grid-connected adaptability analysis of DC wind turbine (DCWT) under the grid-side transient faults is still a blank. In order to study the grid-connected adaptability of the DC wind turbine under the grid-side transient faults, based on the grid-connected system of a DC wind turbine, this paper analyzed the operation characteristics of the DC wind turbine during the period of the grid-side transient faults, and proposed a grid-side transient fault ride-through control strategy. During the period of the grid-side transient faults, additional energy absorbing circuit was attached to the DC wind turbine to absorb the surplus power and stabilize the low voltage side voltage and the dynamic reactive power compensation scheme was proposed in the grid-side converter to provide maximum reactive power support for the fault grid. The simulation model of the grid-connected system based on the DC wind turbine was built for PSCAD/EMTDC. Through the simulation of the model under the fault conditions of grid-voltage drop, rise and continuous change, it was verified that the proposed control strategy effectively improved the grid-connected adaptability of the DC wind turbine under the grid-side transient faults and ensured the safe and stable operation of the DC wind turbine.