Specific energy concept applied to the voltage sag ride-through capability of sensitive equipment in DG embedded systems

A simple distribution system is presented where the effect of distributed generation (DG) presence is analyzed. The concept of specific energy for voltage sag immunity of sensitive equipment under the new scenario created by DG is applied. A short guide for the improvement of the protection/voltage sag coordination is presented through considering overcurrent device location, DG connection point, supply/DG impedance ratio, supply and DG protective device speeds, and protection selectivity/power quality tradeoff.