IEEE Std 1668-2017 PDF

Full title and description

IEEE Std 1668-2017 — IEEE Recommended Practice for Voltage Sag and Short Interruption Ride-Through Testing for End-Use Electrical Equipment Rated Less than 1000 V. This recommended practice defines methods to characterize, reproduce and test the susceptibility and ride-through performance of end-use electrical and electronic equipment connected to low-voltage power systems (nominal/rated voltage less than 1000 V), including single-phase and multiphase balanced and unbalanced voltage sags and short interruptions. It also defines test-equipment requirements, reporting, and certification-related data for voltage-sag ride-through testing.

Abstract

This document provides a non-industry-specific recommended practice for measuring and reporting equipment ability to tolerate voltage sags (dips) and short interruptions lasting less than one minute. It specifies representative voltage-sag waveforms, sag depth and duration definitions, test sequences, instrumentation and setups to ensure repeatable, comparable ride-through test results. The practice supports development of minimum immunity requirements and standardized test reporting for manufacturers, laboratories and certifiers.

General information

• Status: Active (2017 edition currently in use; a PAR to revise/supersede the 2017 edition was approved in 2024).
• Publication date: Published November 27, 2017 (2017 edition).
• Publisher: IEEE (Institute of Electrical and Electronics Engineers), Standards Association.
• ICS / categories: Electrical engineering — power quality, low-voltage power systems, power-distribution testing and measurement; standards for equipment immunity and ride-through testing. (See power-quality and voltage-dip / sag topics).
• Edition / version: 2017 edition (document number 1668-2017).
• Number of pages: Approximately 85 pages (PDF/printed editions).

Scope

Defines recommended procedures for generating and applying voltage-sag and short-interruption test waveforms to end-use equipment rated less than 1000 V, and for observing and recording equipment behavior during and after events. The scope covers characterization of real-world sag statistics, selection of representative test severity levels, test equipment requirements (generators, measurement instruments), phasing and imbalance considerations, pass/fail criteria for ride-through, and templates for test reports and certification records. The recommended practice applies to a broad class of electrical and electronic equipment that can malfunction or shut down due to short-duration reductions in supply voltage.

Key topics and requirements

• Definitions and terminology for voltage sag (dip), short interruption, duration classes, depth/magnitude and phase-angle jump.
• Characterization of real-world voltage-sag events and guidance on selecting representative test waveforms and severity levels.
• Detailed test procedures for applying single-phase and multiphase (balanced and unbalanced) voltage sags and short interruptions to equipment under test.
• Requirements and performance criteria for test equipment (signal/generator fidelity, measurement accuracy, timing resolution, safety and grounding practices).
• Test sequencing, repeatability, and environmental/conditioning pre-test requirements.
• Pass/fail definitions, reporting templates, and recommended information for certification records (observed behavior, recovery time, functional degradation, measurement traces).
• Considerations for unbalanced sags, two-phase sags, and practical implementation notes to reflect diverse installation scenarios.

Typical use and users

Used by: manufacturers of electrical and electronic equipment, independent test laboratories, certification bodies, compliance engineers, power-quality consultants, and utilities interested in specifying minimum ride-through requirements. Typical applications include product development validation, pre-certification testing, acceptance testing for sensitive equipment in industrial/commercial installations, and development of product immunity specifications referenced in procurement documents.

Related standards

Standards and guides frequently referenced alongside IEEE 1668 include power-quality and disturbance monitoring standards (e.g., IEEE 1159 series on power-quality monitoring and terminology), regional supply-quality specifications, and international IEC/ISO documents addressing power-quality assessment and voltage-dip characterization (for example IEC technical specifications on power-quality indices). IEEE 1668 (2014) was the earlier trial-use edition; an errata to the 2017 edition is noted in some bibliographies.

Keywords

voltage sag; voltage dip; ride-through; short interruption; immunity testing; power quality; low-voltage equipment; test procedure; certification; voltage-dip characterization.

FAQ

Q: What is this standard?

A: IEEE Std 1668-2017 is a recommended practice that specifies how to test the ability of end-use electrical and electronic equipment (rated under 1000 V) to withstand and recover from voltage sags (dips) and short interruptions. It defines representative event waveforms, test setups, measurement requirements and reporting formats.

Q: What does it cover?

A: It covers definitions, real-world sag analysis, procedures for generating and applying sag/interrupt waveforms (single- and multi-phase, balanced and unbalanced), test-equipment performance requirements, test sequences and repeatability, pass/fail criteria and recommended reporting for certification and compliance.

Q: Who typically uses it?

A: Manufacturers, test labs, certifiers, consultants and utilities use it to design, validate and certify equipment for immunity to power-quality events, and to establish repeatable, comparable test results for product development and procurement.

Q: Is it current or superseded?

A: The 2017 edition is the active published edition (published Nov 27, 2017). As of 2024 a project authorization (PAR) to revise and supersede the 2017 edition was approved, so a revised edition is in development; until a new edition is published the 2017 document remains the current published recommended practice. Users should check IEEE Standards Association notices for the formal publication of any revised edition.

Q: Is it part of a series?

A: It sits within the IEEE family of power-quality and power-systems recommended practices and guides (related trial-use and full recommended-practice editions, plus cross-references to IEEE 1159 and other power-quality standards). The 2014 trial-use edition preceded the 2017 revision.

Q: What are the key keywords?

A: Voltage sag (dip), short interruption, ride-through, immunity testing, power quality, low-voltage equipment, test procedure, certification.