Electric Power Distribution

Concept Updated 2026-09-24

Two fundamentally different physical topologies get lumped under one term — radial (most of rural and suburban Sweden, one supply path per customer) versus meshed networks (dense urban areas, parallel paths for reliability) — and which one serves a given customer changes what options a DSO even has when congestion hits.

In a radial network there's no alternate path to reroute power around a constraint, unlike the meshed urban topology, so across most of Sweden's grid local flexibility or new cable are literally the only two levers a DSO has, not one of several routing options.

Distribution voltage — 2-33 kVUtilization voltage — 230/400 VTypical urban/suburban substation (UK data) — 150 kVA-1 MVA, serving a few hundred houses

The final stage of electricity delivery: carrying power from the Electric Power Transmission system to individual consumers. Managed by distribution system operators (DSOs) — in Sweden, these are the elnätsföretag (grid companies), e.g. E.ON Energidistribution, Ellevio, Vattenfall Eldistribution.

How it works

Distribution Substations receive power from the transmission/subtransmission grid and step voltage down to medium voltage (2–33 kV).
Primary distribution lines (feeders) carry medium-voltage power along streets, overhead or underground.
Distribution transformers (Distribution Transformer) near customer premises step down to utilization voltage (230/400 V in Sweden/Europe).
Service drops connect individual customers.

Network configurations

Radial: tree-like, each customer has one supply path. Common in rural/suburban areas. Includes emergency reconfiguration capability.
Network: multiple parallel supply paths. Used in dense urban areas for higher reliability.

Regional specifics (Europe / Sweden)

50 Hz, 230 V single-phase / 400 V three-phase
Typical urban/suburban substation (UK data specifically, per the cited source — not separately documented for Sweden, though broadly comparable): 150 kVA to 1 MVA, serving a few hundred houses
Average load sizing (same UK source): 1–2 kW per household, with peak draw allowance of ~10x
Large industrial/commercial customers may have own transformers at 11–33 kV

The distribution grid is changing

Traditionally a passive, one-way delivery system. Now becoming an active, bidirectional network due to:

Distributed generation: rooftop solar, small wind, microgeneration
Electric vehicles: both as load and potential storage (V2G)
Heat pumps: significant new load
Battery storage: behind-the-meter and grid-scale

This transformation is what makes Flexibility at the distribution level necessary. The DSO must manage bidirectional flows, local Congestion Management, and voltage quality — challenges that didn’t exist when power only flowed one way. Demand Response and other flexibility mechanisms become essential tools for DSOs managing this transition.

Market structure

Distribution remains a regulated Natural Monopoly — unlike generation and retail, which began liberalizing in the 1970s–1980s (the cited source doesn’t state a 1990s endpoint). The DSO owns and operates the physical network but (in unbundled markets) does not sell energy. The Clean Energy Package formalizes this: the Electricity Market Directive requires DSOs to act as neutral market facilitators (Art. 31(5)), to procure flexibility via market-based procedures (Art. 32), and prohibits DSO ownership of energy storage (Art. 36, with derogations). In practice, Swedish DSOs use both Villkorade Avtal (conditional connections with curtailment obligations) and local flexibility markets to manage congestion.

(Source - Electric power distribution (Wikipedia))

Sources

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