Distribution grid considerations for large scale solar and wind installations

The distribution power grid paradigm has changed. Renewable energy installations are becoming increasingly popular due to incentives created by public policy, environmental consciousness and the desire by the end user to reduce energy costs. A recent industry report indicates that cumulative grid-tied PV capacity in the U.S. grew to 792 MW by the end of year 2008, with an 81% increase in new grid-tied PV installations in 2008 over 2007 and 53% in 2007 over 2006 [1]. The distribution grid is now viewed as a two way pathway for power, although it was built to carry power in one direction. Small scale, renewable systems are being added to the grid without modeling; however, large scale solar and wind require special power system modeling and analysis to insure the installation does not create voltage violations or protection issues for the distribution grid.