Protection of battery energy storage systems

With the advent of more and more wind generators, and solar projects being placed on the utility grid, Battery Energy Storage Systems will find there way to level out the peaks and valleys these devices generate. It's a prudent protection engineer that understands these new concepts before they are placed on their system. This paper introduced a typical BESS, and discussed its construction, operation, limitations, and finally, protection. Since these are solid state devices, not rotating machines, some rethinking of the normal protection philosophy needs to be done to assure the BESS gets disconnected in a timely manner.