Daisy-chain (MV ring topology)
Also known as: Ring Bus, Loop Topology
A medium-voltage collection layout for utility-scale BESS where a continuous MV cable loops through the site, and each inverter power station (PCS + transformer skid) taps into the ring in parallel via a Ring Main Unit (RMU). Each skid can be isolated for maintenance or fault without de-energising the rest of the plant. Also referred to as a ring bus, MV ring main, or loop topology. The alternative is a radial (home-run) layout where each skid has its own dedicated cable back to the substation.
In energy storage
On larger BESS plants (typically 100 MW+), a daisy-chain MV ring is the standard topology because it provides N-1 redundancy at the MV level without requiring duplicate radial feeders. The ring is typically operated with one switch open (open-ring configuration), and protection relays are coordinated so that a faulted segment is automatically isolated while the remaining blocks continue operating.