The Design of Filter Parameters of Dynamic Voltage Restorer in Medium Voltage Network

Dynamic Voltage Compensator (DVR) is able to handle the dynamic power quality problems in distribution network, such as voltage sags and voltage unbalance, and the parameters of the output filter will have important affect on the compensation results. In this paper, the parameter design method of the output filter of a cascaded H-bridge based DVR applied in medium-voltage distribution grid is studied. Through the analysis of the case when filter inductor current has the maximum value, the theoretical expression of the relationship between the low limit of the value of filter inductor and the capability of voltage compensation and power factor is derived. Meanwhile, the method of selecting the filter capacitor value is obtained. The realization of the proposed method are given by taking an engineering project as an example, the correctness and validity of the design method of filter parameters proposed in this paper are verified by simulation.