| Layer | Function | Technologies | |-------|----------|---------------| | Process | CT/VT, CB, transformer | Merging units, smart sensors | | Bay | Protection & control IEDs | Numerical relays, PLCs, PMUs | | Station | Local SCADA, HMI | IEC 61850 station bus, gateways | | Control center | Wide-area monitoring & control | EMS, WAMS, digital twin, AI analytics |