This impact may manifest either in positive or negative manner depending on the type of DG and its characteristics. The ever increasing levels of the penetration of DG requires a regulation that enables existing DG units connected to the grid without jeopardizing the system stability at the same time acting as an enabler for new technology development. The next section presents a brief review of various control methodologies reported in recent literature of DG integration. This section will be followed by a summary of IEEE grid interconnection requirements for seamless contribution of DG connected to the grid. 1