Digital Substation is an engineering publication focused on IEC 61850 automation, protection systems, and digital grid intelligence.
On 24 September 2025, NamPower commissioned Sekelduin — a 132/66/33 kV indoor switching station near Swakopmund, Namibia, built by ACTOM as Africa's first fully digital substation with IEC 61850 process bus end-to-end.
Top-down IEC 61850 engineering — formalized in TR IEC 61850-90-30:2025 and TR IEC 61850-7-6 (Ed. 2) — moves specification errors from commissioning to the design phase, before a single IED is selected or procured. This article explains the mechanics of the five-step process: what each step produces, what files are exchanged, and why the sequence achieves outcomes the conventional bottom-up approach cannot.
CIGRE Study Committee B5 has opened Working Group B5.90, tasked with writing the first dedicated guidelines for commissioning and testing of fully digital protection and automation control systems. The Terms of Reference, published in January 2026, cover FAT, SAT, and operational testing for IEC 61850 process bus architectures.
In 2023, fourteen European TSOs signed a common statement on IEC 61850 engineering and demonstrated a working proof of concept. Their five-step top-down process — backed by two new IEC technical reports — changes how utilities, IED suppliers, and tool vendors interact. Here is what they built and why it matters.
XML Schema validation checks structure — it cannot verify that a GOOSE subscription references a valid dataset or that a logical node contains required data objects. Object Constraint Language (OCL) fills that gap. IEC TS 61850-6-3, published in 2025, defines how OCL rules should be written and applied to IEC 61850 XML files, laying the groundwork for consistent, formal SCL validation across tools.