Decision guide

IEC 61850, DNP3 and IEC 60870-5-104 compared for a product decision

2026-10-29 · 7 min read

If you are choosing a protocol for a new product, the technical comparison is the least interesting part. All three move points reliably. What actually decides is which market you are selling into, what the buyer already runs, and how much of the integration cost you are willing to absorb on your customer's behalf.

What each is built around

• DNP3 is point-oriented telecontrol with a strong emphasis on event buffers and unsolicited reporting. It is dominant in North American utilities and water/wastewater, and its object model is a catalogue of point types rather than a device description.
• IEC 60870-5-104 is point-oriented telecontrol with explicit windows and timers, dominant in Europe and much of Asia for wide-area telecontrol.
• IEC 61850 is model-oriented and substation-scoped: it describes the device, and it adds peer-to-peer protocols for interlocking and sampling.

The market question

For a product sold to North American utilities, DNP3 is usually mandatory. For European and Asian telecontrol, 104 is the usual requirement. For anything installed inside a substation and connected to IEDs, 61850 is expected regardless of country. A product aimed at global sales typically implements two of the three, and the third arrives with the first customer who asks.

Engineering effort, roughly

• 104 and DNP3 are comparable in implementation size, and both are far easier to test than 61850 because the point list is a document rather than a model.
• 61850 is larger: model handling, SCL parsing, reporting and control semantics, plus optionally GOOSE and SV, which are different problems again.
• The hidden cost in all three is not the happy path but the negative paths: malformed frames, restarts, timeouts and time synchronisation.

A decision that ages well

Build the station data model once, internally, with quality and timestamps attached. Then treat each protocol as an encoding plus a conversation pattern on top of it. Products built this way add a protocol in weeks; products where the protocol owns the data model add one in quarters, and each addition introduces a new class of inconsistency between protocols.

Questions that come up

Can one device serve all three?

Yes, and gateways do exactly that. The constraint is CPU and network budget, plus the maintenance cost of three protocol stacks in one product.

Is DNP3 used in Europe?

It appears in specific sectors and in equipment imported from North America, but 104 and 61850 dominate utility specifications.

Which is easiest to get right first time?

104 for telecontrol, largely because the conformance behaviour is well described and the failure modes are enumerable. 61850 is harder to get right because the surface area is larger.

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