Energy & power systems guide
Distribution Substations
How transmission or subtransmission power enters local distribution systems.
Electrical safety boundary: this page explains the system conceptually. It does not provide procedures for live electrical work, switching, protection settings, conductor/breaker sizing, substation access or high-voltage operation. Those activities require qualified professionals, applicable codes and utility procedures.
Where this fits
How transmission or subtransmission power enters local distribution systems.
Core system ideas
Distribution substations transform incoming voltage to levels used by local feeder networks.
Bus arrangements, breakers, protection and controls divide power among outgoing feeders.
Capacity planning must account for normal peaks, contingencies, maintenance and future demand.
Interfaces and tradeoffs
Distribution connects the bulk system to millions of individual loads and increasingly to distributed generation and storage. Local voltage, feeder capacity and asset condition matter as much as system-wide energy supply.
What organizations measure
Transformer loading, feeder demand, bus voltage, outages and reserve capacity.