CASCADED H-BRIDGE MULTILEVEL INVERTER BASED D-STATCOM USING GOERTZEL ALGORITHM

Voltage sag is the major power quality issue in modern power systems. The presence of power converters for various industrial and domestic power control applications introduces voltage sag, which adversely affects the performance of all the equipment connected to the power system. Distributed Static Compensator (D-STATCOM) is an efficient custom power device to overcome this issue. Its advantages include fast dynamic response and power factor correction. D-STATCOMS can mitigate the load harmonics and also, they can prevent the load harmonics flowing into the source. This will also prevent from point of common coupling voltage degrading. The performance of D-STATCOM depends on the accuracy of sag detection. This paper presents a two-level inverter and seven-level Cascaded H-Bridge Multilevel Inverter (CHBMLI) based D-STATCOM with Goertzel Algorithm for accurate sag detection. Application of the Goertzel algorithm helps in finding the fundamental voltage component in such a way that the compensation happens during sag alone. The simulation results, showing the extraction of the fundamental component using the Goertzel algorithm are presented in this paper.