IEC TR 61869-100-2017 PDF

Full title and description

IEC TR 61869-100:2017 — Instrument transformers — Part 100: Guidance for application of current transformers in power system protection. This Technical Report provides guidance on the correct application, performance expectations and interpretation of behaviour of inductive protective current transformers (CTs) used with protection relays and measurement devices; it is intended to complement the requirements of IEC 61869-2 and to assist relay manufacturers, CT manufacturers, utilities and project engineers in understanding CT response under fault and transient conditions.

Abstract

This Technical Report explains practical considerations for applying inductive current transformers in power-system protection schemes. It describes CT behaviour for simplified and standard short‑circuit signals, discusses saturation effects, waveform distortion and the associated implications for protective relays, and clarifies responsibilities during CT design and selection. A corrigendum issued in 2023 is incorporated in available copies.

General information

• Status: Published (Technical Report).
• Publication date: 20 January 2017 (Edition 1.0).
• Publisher: International Electrotechnical Commission (IEC).
• ICS / categories: 17.220.20 — Measurement of electrical and magnetic quantities.
• Edition / version: Edition 1.0 (2017); Corrigendum 1 published October 2023 (included with many distributions).
• Number of pages: 135 pages (IEC webstore listing; national adoptions/derivatives may show slightly different page counts).

Scope

Applies to inductive protective current transformers that meet the requirements of IEC 61869-2 and provides guidance for their application in power-system protection. The report addresses how CTs respond to simplified and standardized short‑circuit signals, gives information for both casual users and specialists (with declared abstraction levels where necessary), and discusses allocation of responsibilities in CT design and project specification.

Key topics and requirements

• Guidance on selection and application of inductive current transformers for protection purposes.
• Explanation of CT response to fault waveforms, including steady‑state and transient behaviour and saturation phenomena.
• Methods to characterise CT performance under standardized short‑circuit signals and simplified test signals.
• Recommendations for coordination between CT manufacturers, relay manufacturers and system designers; clarification of roles and responsibilities in specification and testing.
• Incorporation of corrigendum changes (mathematical corrections and clarifications as issued in 2023).

Typical use and users

The report is used by protection engineers, relay and CT manufacturers, testing laboratories, utility protection and commissioning teams, consulting engineers and project specifiers who need to understand CT behaviour under fault and transient conditions and to prepare accurate CT specifications for protection applications. It is also a reference for training and internal company procedures related to CT selection and verification.

Related standards

Related and complementary documents include the IEC 61869 series (instrument transformers) in particular IEC 61869-1 and IEC 61869-2, historical/current CT standards such as IEC 60044 family, and industry practice documents (examples: IEEE C37.x series for protective devices). National adoptions and translations (for example DIN/VDE publications) may exist that incorporate this Technical Report.

Keywords

current transformer, CT, instrument transformer, protection, power system protection, saturation, transient response, IEC 61869, CT specification, relay coordination

FAQ

Q: What is this standard?

A: IEC TR 61869-100:2017 is a Technical Report providing guidance for application of inductive current transformers specifically for power‑system protection. It complements normative requirements in IEC 61869-2 by offering explanatory guidance and practical application advice.

Q: What does it cover?

A: It covers CT behaviour under fault and transient conditions, interpretation of simplified and standardized short‑circuit signals, practical implications of CT saturation and waveform distortion for protective relays, and guidance on specification and allocation of responsibilities during CT design and procurement.

Q: Who typically uses it?

A: Protection engineers, CT and relay manufacturers, utility protection teams, testing laboratories, consultants and project engineers involved in designing, specifying, installing or testing CTs used for protection.

Q: Is it current or superseded?

A: The document is the 2017 edition (Edition 1.0) and remains the published Technical Report; a Corrigendum 1 was issued in October 2023 and is often included with the official publication. The IEC listing shows a stability date through 2027. Users should check national adoption notices or the IEC webstore for any later amendments or replacement work.

Q: Is it part of a series?

A: Yes — it is part of the IEC 61869 series on instrument transformers (the 61869 series replaces older instrument-transformer standards and includes parts such as IEC 61869-1 and IEC 61869-2 which set normative requirements).

Q: What are the key keywords?

A: Current transformer (CT), instrument transformer, protection, saturation, transient response, IEC 61869, CT specification, relay coordination.