Electric power distribution (Wikipedia)

Summary

Electric power distribution is the final stage of electricity delivery, carrying power from the Electric Power Transmission system to individual consumers. Substations connect to the transmission system and step down voltage to medium voltage (2–33 kV) using transformers. Primary distribution lines carry this to Distribution Transformers near customer premises, which further reduce voltage to utilization levels (e.g. 230/400 V in Europe, 120/240 V in North America).

Key points

• Distribution substations transition from transmission to distribution: circuit breakers, transformers stepping down to medium voltage, and busbars splitting power into multiple feeders.
• Network configurations: radial (tree-like, one source per customer) vs. network (multiple parallel sources, used for concentrated loads via “spot networks”). Radial is common in rural/suburban areas.
• Urban distribution is mainly underground; rural mostly overhead on utility poles; suburban is mixed.
• Primary distribution voltages range from 4–35 kV. Only large consumers connect directly at this level.
• Secondary distribution delivers at utilization voltage. Europe uses 230/400 V three-phase at 50 Hz. North America uses 120/240 V split-phase at 60 Hz.
• Deregulation (1970s–1980s onward): generation and retail became competitive markets, but distribution remained regulated as a Natural Monopoly.

Relevance to flexibility

The article’s final section on modern distribution systems is the directly relevant part: it describes how heavy DER integration at the distribution level is gradually decoupling distribution grids from the transmission network and turning them into bidirectional, microgrid-like systems whose supply–demand balancing needs new economic, technological, and operational tools — market signals, battery storage, data analytics, and optimisation.

This is the core context for why Flexibility at the distribution level matters: DER integration is transforming the distribution grid from a passive one-way delivery system into an active, bidirectional network requiring new balancing tools.