Case Studies on the Distribution System Operation Considering DSO–VPP Coordination and Field Applications of Non-Wires Alternatives (NWAs)

We propose and field-test an ISO–DSO–VPP coordination scheme for distribution-level operation under a Total DSO assumption. The scheme links day-ahead prequalification (1-h resolution, up to three guidance–rebidding iterations) with real-time control (15-min operating interval with 1-min monitoring) so VPP bids and dispatch respect feeder limits (0.95–1.05 p.u., 10 MVA at 22.9 ㎸). We also position ESS-based non-wires alternatives (NWAs) to relieve overloads and defer upgrades while increasing hosting capacity. Field applications in Korea include (i) three feeders in Gwangju–Jeonnam validating constraint clearance via the prequalification–rebidding loop, and (ii) one feeder in Jeju where ESS-based NWAs over ten days achieved 0.2–1.5 ㎿ peak reduction, indicating credible deferral potential. The results clarify the DSO’s operative role and show how LNBA/GNA evaluation can be aligned with market and distribution operations.