Category Archives: IEC 61850

A complete reference for substation engineers comparing the IEC 61850 process bus and station bus — what each bus does, protocols used, hardware requirements, time synchronization needs, redundancy strategies, bandwidth, topology, and procurement considerations Quick Comparison Table Aspect Process Bus Station Bus Purpose Real-time measurement + trip SCADA, configuration, supervisory Replaces Analog CT/VT wiring + binary trips Conventional… Read More »

Digital substations require time synchronization accurate to better than 1 microsecond. Sampled Values, GOOSE, sequence-of-events recording, traveling-wave fault location, and synchrophasor measurements all rely on precise time across the entire substation network. Standard IEEE 1588v2 (PTP) is powerful but too flexible — it has dozens of options and many possible configurations. To get interoperable, reliable, sub-microsecond timing in… Read More »

A complete reference for substation engineers covering Merging Units — IEC 61869-9 specification, processing delay limits, sample rates, variant codes, SmpSynch values, conformance classes, holdover mode, PTP/1PPS synchronization, procurement template, and field troubleshooting Quick Reference Item Value What it does Digitizes CT/VT signals and publishes Sampled Values on the process bus Standard IEC 61869-9:2016 (replaces 9-2LE guideline) Transport… Read More »

Every piece of data in an IEC 61850 system lives inside a logical node. A circuit breaker position is inside XCBR. An overcurrent trip signal is inside PTOC. A voltage measurement is inside MMXU. A GOOSE control block is inside LLN0. Logical nodes are the building blocks of the IEC 61850 data model. They represent functions — not… Read More »

If you work with IEC 61850, you will deal with SCL files. They are the standard way to describe IED capabilities, substation configurations, and communication parameters. But the first thing that confuses most engineers is this: there are six different SCL file types. ICD, SSD, SCD, IID, CID, SED — each with a different purpose, created by a… Read More »

IEC 61850 transformed substation automation. It replaced hardwired copper connections with standardized Ethernet-based communication between intelligent electronic devices (IEDs). GOOSE messages trip breakers in under 4 milliseconds. MMS connects IEDs to SCADA systems. Sampled Values stream real-time voltage and current measurements. But this transformation came with a trade-off. By moving protection and control communications onto Ethernet, substations inherited… Read More »

Ethernet is the backbone of modern substation automation. Protection relays, bay controllers, merging units, and SCADA gateways all communicate over Ethernet networks carrying time-critical GOOSE messages, Sampled Values, and MMS traffic. But substations are among the harshest environments for communication equipment. High electromagnetic interference, wide temperature swings, vibration, and electrical transients are the norm. A commercial office switch… Read More »

IEC 61850 has become the global standard for substation communication systems, enabling interoperability between protection relays, bay controllers, SCADA systems, and engineering tools. At the heart of IEC 61850 client/server communication is MMS (Manufacturing Message Specification)—and one of the most searched questions is: What port number does IEC 61850 MMS use? This article provides a complete explanation of… Read More »

IEC 61850 does not treat control operations as simple “write a value and hope it works.” Instead, it defines formal control models that describe how a command is issued, who is allowed to issue it, and how safety is guaranteed. These control models are one of the most important — and most misunderstood — parts of IEC 61850.… Read More »

Everything engineers need to know about Basic Types, Common Data Classes, and how they appear in GOOSE, Sampled Values, MMS, and SCL. IEC 61850 is much more than a communication protocol—it is a semantic language designed to describe protection, control, measurement, and automation inside modern substations. At the core of this language lies one essential concept: 👉 Every… Read More »