Research on Low voltage ride through Control Technology Based on Dynamic Voltage Restorer

Large-scale wind power access to the power grid poses great challenges to the safe operation and management of the power grid. The new power grid guidelines require that wind turbines should be equipped with low voltage ride through (LVRT) capabilities. Considering that the dynamic voltage restorer (DVR) has the advantage of being able to quickly and accurately perform voltage compensation in a short time, this paper proposes a fault ride-through scheme for doubly-fed wind turbine based on the dynamic voltage restorer. Aiming at the detection delay and attenuation caused by the filter in DVR, an integral detection method based on the theory of instantaneous reactive power is adopted to reduce the influence of the filter. According to the control characteristics of DVR, a DVR control algorithm based on the double Q-P theory of coordinate transformation is proposed, which can compensate the transient voltage disturbance and effectively improve the compensation performance of the dynamic voltage restorer. Using PSCAD / EMTDC simulation software to establish a simulation platform, the simulation results show that when a serious short-circuit fault occurs during the transmission of electrical energy from the wind farm to the grid, the DVR can quickly detect voltage changes and accurately compensate for the required voltage to obtain the ideal transient characteristics Improves the low voltage ridethrough performance of wind turbines.