IEEE Std C57.124-1991 (2002) PDF

Full title and description

IEEE Std C57.124-1991 (R2002) — Recommended Practice for the Detection of Partial Discharge and the Measurement of Apparent Charge in Dry‑Type Transformers. This recommended practice defines methods, instrumentation characteristics and test procedures for detecting partial discharges (PD) that occur in the insulation of dry‑type transformers or their components and for measuring the associated apparent charge at the transformer terminals using wideband measurement techniques.

Abstract

This document provides guidance for PD detection and apparent‑charge measurement in dry‑type transformers when an alternating test voltage is applied. It describes the required characteristics of detection systems and calibrators, sets out calibration and test procedures (including conditioning and test‑voltage requirements), and offers interpretation guidance for observed PD signatures. The wideband detection method is the primary technique covered.

General information

• Status: Inactive‑Reserved. Originally approved and published in 1991; later reaffirmed (R2002 and R2009) and administratively inactivated.
• Publication date: Original publication November 30, 1991 (ANSI approval Oct 11, 1991); reaffirmation editions issued in 2002 and 2009.
• Publisher: Institute of Electrical and Electronics Engineers (IEEE), Power & Energy Society / Transformers Committee.
• ICS / categories: Electrical engineering — Transformers and Reactors (ICS 29.180).
• Edition / version: IEEE Std C57.124‑1991 (reaffirmed R2002; often referenced as the 1991 document with a 2002 reaffirmation).
• Number of pages: 32 pages (typical published PDF/hardcopy length).

Scope

The recommended practice applies specifically to detection of partial discharges in dry‑type transformers and to procedures for measuring the apparent charge at the transformer terminals under alternating test voltages. It defines the wideband method of detection, describes the required elements of PD detection systems (high‑voltage coupling circuits, measuring impedances, filters, display and discharge meters), sets calibrator characteristics, and establishes test and conditioning procedures along with guidance for recognizing and interpreting PD activity.

Key topics and requirements

• Definition and application of the wideband partial‑discharge detection method for dry‑type transformers.
• Required characteristics and performance of PD detection systems, including high‑voltage coupling and measuring impedance elements.
• Calibrator specifications (calibrating capacitor, pulse generator characteristics, output impedance and amplitude) and calibration procedures.
• Test procedures: conditioning, selection of test voltage, transformer connections, disturbance handling, and interpretation of anomalous results.
• Measurement of apparent charge at transformer terminals and guidelines for traceability and calibration to reference standards.
• Annex on PD recognition and guidance for distinguishing PD from external noise and test artifacts.

Typical use and users

Used by transformer manufacturers, independent test laboratories, utilities, commissioning and maintenance engineers, and forensic analysts performing failure investigations. Typical applications include factory acceptance testing of dry‑type transformers, on‑site condition assessment, root‑cause analysis of insulation problems, and development or verification of PD test procedures and equipment calibration.

Related standards

Frequently used alongside other IEEE transformer standards and guides such as IEEE Std C57.12.x series (test codes for liquid‑immersed and dry‑type transformers), IEEE Std C57.12.91 (test code for dry‑type transformers), IEEE C57.104 (interpretation of dissolved gases in oil), IEEE C57.125 (failure investigation guide), and other measurement and loss‑evaluation guides. These documents are commonly cross‑referenced when establishing comprehensive test, acceptance and condition‑monitoring programs for transformers.

Keywords

partial discharge; PD detection; apparent charge; dry‑type transformer; wideband measurement; calibrator; PD test procedure; transformer testing; insulation diagnostics; IEEE C57.124.

FAQ

Q: What is this standard?

A: IEEE Std C57.124‑1991 (R2002) is a recommended practice that specifies methods for detecting partial discharges and measuring apparent charge in dry‑type transformers, with detailed requirements for measurement systems, calibrators and test procedures.

Q: What does it cover?

A: It covers the wideband PD detection method, system and calibrator characteristics, calibration and traceability procedures, test configurations and conditioning, disturbance handling, and interpretation of PD measurements (including an informative annex on PD recognition).

Q: Who typically uses it?

A: Transformer manufacturers, utilities, independent testing laboratories, commissioning and maintenance personnel, and engineers conducting failure investigations or condition monitoring.

Q: Is it current or superseded?

A: The original document was published in 1991 and later reaffirmed (including a 2002 reaffirmation). IEEE records show the standard was placed in inactive/inactivated status in administrative updates; users should check current IEEE SA records for the latest active or superseding documents before relying on it as a normative reference.

Q: Is it part of a series?

A: Yes. It is part of the IEEE C57.x family of standards and guides related to power and distribution transformers (test codes, installation and maintenance guides, loss evaluation and failure investigation documents). It is commonly used together with C57.12.x test codes and other C57 guides.

Q: What are the key keywords?

A: Partial discharge, apparent charge, dry‑type transformer, wideband PD detection, PD calibrator, transformer testing, insulation diagnostics.