IEEE Std C57.123-2019 PDF

Full title and description

IEEE C57.123-2019 — IEEE Guide for Transformer Loss Measurement. This guide provides information and general recommendations on instrumentation, circuitry, calibration, and measurement techniques for no‑load losses (excluding auxiliary losses), excitation current, and load losses of power and distribution transformers; it is intended to complement the test‑code procedures in IEEE Std C57.12.90.

Abstract

This guide describes practical and theoretical measurement methods used to obtain accurate transformer loss data. Topics include selection and calibration of instruments, measurement circuit arrangements, methods for measuring no‑load and load losses and excitation current, uncertainty estimation, interpolation/extrapolation of test data, grounding and shielding, and procedures for traceability to reference standards. The guide applies to liquid‑immersed and dry‑type transformers, step‑voltage regulators, and both single‑ and three‑phase units.

General information

• Status: Active Standard (revision of IEEE C57.123‑2010).
• Publication date: Published February 10, 2020 (Board approval November 7, 2019).
• Publisher: IEEE (Institute of Electrical and Electronics Engineers), Power & Energy Society / Transformers Committee.
• ICS / categories: Transformers and reactors (ICS reference commonly shown as 29.180 / transformer test and measurement).
• Edition / version: 2019 edition (designation IEEE C57.123‑2019; revision of the 2010 edition).
• Number of pages: 55 pages (published/pdf commercial listings typically show 55 pages).

Scope

The guide gives recommendations and background for achieving the accuracy requirements of the transformer test codes (notably Clauses 8 and 9 of IEEE Std C57.12.90) and explains reasons for specified procedures and limits. It covers measurement techniques for no‑load (core) losses, excitation current, and load losses; calibration, certification, and traceability of measurement equipment; methods to estimate and combine uncertainty; grounding and shielding practices; and practical examples, schematics, and anomaly handling. It applies to liquid‑immersed and dry‑type power and distribution transformers, step‑voltage regulators, and single‑ and three‑phase units.

Key topics and requirements

• Recommended instrumentation and measurement circuitry for loss and excitation current tests.
• Calibration and traceability procedures for meters and reference standards.
• Measurement methods for no‑load (core) losses and load losses, and how to exclude auxiliary losses.
• Uncertainty estimation and propagation for loss measurements and reporting of results.
• Grounding, shielding, and wiring best practices to minimize measurement error and interference.
• Interpolation/extrapolation methods for test data and guidance on valid limits and assumptions.
• Examples, schematics, and discussion of common test anomalies and corrective actions.
• Guidance intended to complement IEEE Std C57.12.90 and related transformer test codes.

Typical use and users

Used by transformer manufacturers, independent test laboratories, utility test engineers, quality and metrology staff, and standards committees. Typical uses include preparing and executing loss and excitation current tests, choosing and calibrating instrumentation, estimating test uncertainty, diagnosing anomalous test results, and documenting traceability to reference standards for acceptance testing and type‑testing of power and distribution transformers.

Related standards

Closely related to IEEE Std C57.12.90 (test code for liquid‑immersed distribution, power, and regulating transformers) and IEEE Std C57.12.91 (dry‑type transformers test code). It supersedes IEEE C57.123‑2010. For international comparison, IEC/EN transformer test documents such as IEC 60076 series (including loss measurement guidance in recent IEC 60076‑19‑1 editions) cover similar topics and are commonly referenced alongside IEEE guidance.

Keywords

transformer loss measurement, no‑load loss, load loss, excitation current, calibration, measurement uncertainty, transformer testing, grounding and shielding, IEEE C57.123, C57.12.90.

FAQ

Q: What is this standard?

A: IEEE C57.123‑2019 is a guide that provides recommendations and background for accurate measurement of transformer losses and excitation current; it supplements IEEE transformer test codes to help practitioners achieve required accuracy and traceability.

Q: What does it cover?

A: It covers instrumentation and circuit arrangements, calibration and traceability, methods for measuring no‑load and load losses and excitation current, uncertainty estimation, grounding/shielding practices, interpolation/extrapolation of results, and example schematics and anomaly handling.

Q: Who typically uses it?

A: Transformer manufacturers, utility test engineers, independent test laboratories, metrology and quality staff, and standards developers use this guide to plan and perform loss measurements and to document measurement accuracy and traceability.

Q: Is it current or superseded?

A: As published it is the 2019 revision (published February 10, 2020) and is the active IEEE guide superseding C57.123‑2010. Users should check IEEE or their national standards body for any later amendments or superseding documents.

Q: Is it part of a series?

A: Yes — it is part of the IEEE C57 family of transformer standards and is intended to be used with related test codes such as IEEE Std C57.12.90 and C57.12.91; it complements other C57 documents addressing transformer performance, testing, and recommended practices.

Q: What are the key keywords?

A: transformer loss measurement, no‑load loss, core loss, load loss, excitation current, calibration, traceability, measurement uncertainty, grounding, shielding, transformer testing, IEEE C57.123.