Enhancement of Fault/Low voltage Ride through of Power Grid supporting STATCOM using Droop Current Control of Micro Grid
Integration of wind mills to electrical power grid has increased rapidly at recent years. Windmills which make up with squirrel cage induction generator especially has many features, such as being able to control its reactive power increasing the level of power grid connected wind mills and has made it highly necessary to contribute the overall system stability. Some developed countries address the requirement of reactive power related to the FRT and low voltage capability and grid code requirements of wind mills has to satisfy. Consequently, Interconnection of secondary service which includes micro grid and primary service of main power grid and its stable operation enhances the Fault/Low voltage ride through capability. This control strategy coordinates the power injection for balanced and unbalanced fault condition makes the two level hierarchical control structure between main and micro power grid. Droop control strategy of STATCOM coordinates primary service comprise of current at inner loops, voltage or power and provides supplementary reactive power based on the inner loop current gain for symmetrical and asymmetrical faults. Therefore, proposed secondary services make sure the positive, negative and zero sequence compensation as to improve the power quality.