The Power of Small: The Effects of Distributed Energy Resources on System Reliability

It's a sunny day in Honolulu, Hawaii , and rooftop photovoltaic (PV) systems across the island are serving a significant penetration of the load. A large generator trips offline, and frequency drops quickly-to the point where a block of load is shed to restore the balance between generation and load. However, disengaging those feeders disconnects not only the load but also the PV generation on those feeders; so balance is not restored and frequency continues to drop.