BS EN IEC 61869-9-2019 PDF

Full title and description

STB BS EN IEC 61869-9:2019 — Instrument transformers. Part 9: Digital interface for instrument transformers. This British/adopted European version of the IEC product standard defines the digital communication interface, information models and timing requirements for instrument transformers that provide measurements in digital form (including merging units and sampled values).

Abstract

BS EN IEC 61869-9:2019 specifies requirements and recommendations for the digital interface of instrument transformers. It defines how analogue measurements from instrument transformers are converted to, represented by, and transmitted as sampled-value digital messages for use in protection, metering and monitoring systems. The standard aligns instrument-transformer product requirements with substation communication principles from the IEC 61850 family and includes provisions for time synchronization, accuracy classification, merging units and interoperability with legacy digital solutions it replaces.

General information

• Status: Published / Active (national adoption: BS EN IEC).
• Publication date: 19 August 2019 (BS EN IEC 61869-9:2019).
• Publisher: BSI (British Standards Institution) — adoption of IEC document.
• ICS / categories: 17.220.20 (Measurement of electrical and magnetic quantities).
• Edition / version: 2019 (first published adoption as BS EN IEC 61869-9:2019).
• Number of pages: 66 (approx.).

Scope

This part of the IEC 61869 family applies to instrument transformers that provide digital outputs and to merging units that forward sampled values derived from instrument-transformer measurements. The standard specifies the digital message structure, information models, timing and synchronization requirements, accuracy classification for measuring and protection channels, and interoperability rules for integrating instrument-transformer digital output into substation automation systems. It also replaces the earlier IEC 60044-8 digital solution and maps requirements to IEC 61850 sampled-value services and network time protocols where appropriate.

Key topics and requirements

• Definition of a digital interface and information model for instrument transformers, aligned with IEC 61850 principles.
• Sampled-value message formats and recommended numeric representation (designed to exploit the wider dynamic range of modern sampled-data messages).
• Requirements for merging units (SAMUs), including functional roles, channel labelling and channel-to-measurement mapping.
• Accuracy classification and dual-rating approach for protection and measurement channels (separate classes documenting measuring vs protection accuracy).
• Time synchronization requirements for sampled values (network-based synchronization using IEC 61588 / PTP and options such as 1PPS where applicable).
• Backwards compatibility and migration guidance relative to legacy digital interface solutions (replacement of IEC 60044-8 and alignment with IEC 61850-9-2 implementations).
• Interoperability and testing considerations for accurate delivery of sampled values to relays, meters and other protection/automation equipment.

Typical use and users

Used by utilities, substation automation engineers, protection and control equipment manufacturers, instrument-transformer manufacturers, test laboratories and integrators. Typical applications include protection, revenue metering, monitoring and diagnostics in secondary substations and power-distribution systems where instrument transformers publish sampled-value measurements onto substation networks.

Related standards

Key related documents and series include IEC 61869-1 (general requirements for instrument transformers), IEC 61869-6 (particular requirements), IEC 61850 (substation communication architecture, in particular IEC 61850-9-2/9-2LE for sampled values), IEC 61588 (PTP time synchronization), IEC/IEEE 61850-9-3 (time synchronisation profile), and the superseded IEC 60044-8 (earlier digital solution). Other parts of the IEC 61869 family (Parts 7, 8, 12–15) are also relevant for product-specific requirements.

Keywords

Instrument transformer, digital interface, sampled values, merging unit (SAMU), IEC 61850, IEC 61869, time synchronization, PTP, protection accuracy, metering, sampled-value messages, interoperability.

FAQ

Q: What is this standard?

A: BS EN IEC 61869-9:2019 is the British/European adoption of IEC 61869‑9, the part of the instrument-transformer product family that defines the digital interface for instrument transformers and merging units that provide sampled-value digital outputs.

Q: What does it cover?

A: It covers the digital communications, information models, sampled-value message formats, accuracy classification for measuring and protection channels, time-synchronization requirements and interoperability rules needed to integrate instrument-transformer digital outputs into substation automation and protection systems.

Q: Who typically uses it?

A: Utilities, substation automation engineers, protection-relay and meter manufacturers, instrument-transformer and merging-unit manufacturers, testing laboratories and system integrators use the standard when designing, testing and specifying digital instrument-transformer interfaces.

Q: Is it current or superseded?

A: The document was published as BS EN IEC 61869-9:2019 and is the current adopted text from 2019. National bodies and BSI record activity such as tracked changes or amendment work from time to time; users should check with their national standards body or the publisher for any amendments or revisions since 2019 before relying on it for procurement or compliance.

Q: Is it part of a series?

A: Yes — it is part of the IEC 61869 family for instrument transformers and is intended to be used together with IEC 61869-1, IEC 61869-6 and other product-specific parts. It also tightly references and maps to the IEC 61850 series for substation communications.

Q: What are the key keywords?

A: Instrument transformer, digital interface, sampled values, merging unit, IEC 61850, time synchronization, PTP, protection accuracy, metering, interoperability.