Abstract:
The renewable energy grid code stipulates that wind power integrated system should have the capability of continuous voltage ride through, but existing fault ride through control strategies mainly keep the reactive current scale factors as fixed values and lack a basis for a quantitative description of the reactive current scale factor, which leads to problems such as voltage continuity faults and converter over-modulation. To solve this problem, this paper proposes a voltage continuous ride through control strategy with dynamic reactive current scale factor. This strategy divides the fault voltage interval based on the active current magnitude and the cut-in time of the reactive power compensation device. Dynamic reactive current scaling factors of wind farms under different fault voltages is also calculated in real time, according to the requirements of the grid code, converter overcurrent limit, over modulation, operating conditions of the wind turbine before the fault and subsequent voltage continuity faults and other constraints. The strategy can maximize the voltage active support capability of the wind power integrated system while satisfying the constraints, and ensure safe and stable operation of the wind power integrated system during voltage continuity faults. Finally, a simulation model is built in the PSCAD/EMTDC software platform to verify the correctness of the above analysis.