The grid codes of power systems with high penetration of renewable sources impose stringent requirements on the operation of Distributed Renewable Energy Sources (DRES) under the unbalanced grid faults. A generalized power control strategy based on the symmetrical components is used in this paper to control the power delivery under unbalanced grid faults. The aim of this paper is to develop a reference current selection module for the current controller of grid-side converters, which would be adaptable to the grid requirements. The proposed joint strategies help the DRES to benefit from the linear controllability. The performance of the flexible control strategy and the joint strategies are evaluated, considering the power quality indices.