Can DNP3 and IEC 61850 coexist in the same substation?

Yes, and this is the normal architecture in a modern substation, not an exception. IEC 61850 handles protection and automation within the substation LAN (GOOSE, Sampled Values, MMS for engineering access), while DNP3 — frequently DNP3/IP now — carries aggregated data from a gateway or RTU at that substation back to the utility's SCADA control center over the wide-area network. They operate at different layers of the same overall system rather than competing for the same role.

What does GOOSE stand for and what makes it fast?

GOOSE stands for Generic Object Oriented Substation Event. It achieves its speed by being a Layer 2 Ethernet multicast message with no IP stack, no master-slave polling, and no acknowledgment handshake in the critical path — a relay simply multicasts a state-change message directly to any IED subscribed to it on the station bus, and repeats it at decreasing intervals for reliability. Removing the request-response round trip that protocols like DNP3 rely on is what gets GOOSE into the single-digit-millisecond range needed for protective relaying.

Is DNP3 only used by electric utilities?

No. DNP3 originated in electric utility SCADA but is very widely used across water and wastewater treatment, oil and gas pipeline and wellhead telemetry, and other critical infrastructure with the same underlying communications problem — a control center or master station polling remote sites over a WAN link. Its point-based data model with time-stamped events translates well beyond the power grid.

Does IEC 61850 use IP addressing like DNP3 does?

Partially. The MMS-based engineering and monitoring access in IEC 61850 does run over TCP/IP. But GOOSE and Sampled Values — the two services responsible for its sub-millisecond performance — are sent as raw Ethernet frames with reserved EtherTypes, multicast directly at Layer 2 with no IP addressing involved, specifically to avoid the latency and overhead a full network-layer stack would add to a protection-critical message.

Where do DNP3 and IEC 61850 sit relative to the Purdue model?

DNP3 traffic typically spans the boundary between Purdue Level 1/2 (remote RTUs and local automation at a substation or field site) and the control center's Level 2/3 SCADA systems, since its whole purpose is wide-area communication across that boundary. IEC 61850 GOOSE and Sampled Values traffic stays almost entirely within Level 0/1 — it is intra-substation communication between field devices and protection relays that never needs to leave the local process/station bus to do its job.

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Concept Explainer · SCADA

DNP3 vs. IEC 61850

Both are critical-infrastructure protocols built around timing — but one was built to survive a slow wide-area link between a control center and RTUs scattered across a service territory, and the other was built to trip a breaker in under a millisecond between two relays on the same substation LAN.

DNP3 and IEC 61850 both show up on electric utility networks, both carry safety- and grid-reliability-relevant data, and both are frequently described as "the utility SCADA protocol" — which invites confusion about which one actually does what. They were built for different domains at different distances and timescales. DNP3 (Distributed Network Protocol) originated in electric utility SCADA and telemetry over wide-area links — a control center master polling remote terminal units at substations, pumping stations, and feeders scattered across a service territory, often over serial radio, leased line, or now IP/DNP3 over Ethernet. IEC 61850 originated specifically for substation automation — communication within a single substation, between protection relays (IEDs, Intelligent Electronic Devices) and the station bus, where GOOSE (Generic Object Oriented Substation Event) messaging can trip a circuit breaker in under a millisecond. Same industry, very different design center.