IEEE 1668:2014 pdf free download – IEEE Trial-Use Recommended Practicefor Voltage Sag and Short Interruption Ride-Through Testing for End-Use Electrical Equipment Rated Less than 1000 v
1.1 Scope
This document is a non-industry-specific recommended practice for voltage-sag ride-through performanceand compliance testing for all electrical and electronic equipment connected to low-voltage power systems(with nominal/rated voltage less than 1000 V) that can experience malfunction or shutdown as a result ofreductions in supply voltage lasting less than one minute.The recommended practice includes definingminimum voltage-sag immunity requirements based on actual voltage-sag data. A clause dedicated to thedetailed analysis of voltage sags experienced by end users provides insight into real-world voltage sags.Testing procedures and requirements for test equipment are clearly defined within this document to reflectthe electrical environment,including single-phase,two-phase,and three-phase, balanced and unbalancedvoltage sags.The recommended practice also defines requirements for certification and test reporting,including characterization of voltage-sag ride-through equipment.
1.2 Purpose
The purpose of this recommended practice is to clearly define test methods and ride-through performancefor determining the sensitivity of electrical and electronic equipment to voltage sags.Analysis of real-worldsags provides the foundation for both test methods and performance criteria, aligning themselves as closelyas possible to the end user’s electrical environment.The recommended practice will define thecharacteristics in terms of the depths/magnitudes,durations，phase angles， and vectors of voltage sagsrequired to relate to real-world voltage sags. The recommended practice will show how different voltage-sag testing methods can be used to simulate real-world sags.End users will be able to use the recommendedpractice in their purchase specifications to ensure the required level of equipment performance. In addition,end users can use the voltage-sag criteria as a performance benchmark for existing equipment. Thisrecommended practice can be used to provide a benchmark that can be used to identify equipment that hasenhanced ride-through characteristics.
4.1 Background on voltage sags
Electrification has been called the greatest engineering achievement of the 20th Century, even though mostof us today view it as a basic necessity. With the flick of a switch, our quality of life dramatically improves.While the electricity delivered today generally meets the demands of the average consumer,the powerquality and reliability of delivered electrical energy can vary significantly over time and from one region toanother. Interruptions in electrical service and voltage anomalies can be common and accepted in some areas of the world.However，in today’s more highly developed industrial and digital economies， themanufacturing processes have more stringent power quality requirements. These requirements haveresulted in customers expecting higher-quality and continuity of clectrical power supply with significantreductions in interruptions, as well as other power quality disturbances. However, even in the most highlydeveloped power systems,variations in voltage do occur from time to time,and these variations affectsome customers more than others.Interruptions，voltage sags， swells, overvoltages， harmonics, switchingtransients,flicker, and many other power quality events and disturbances are realities of all electric powersystems.
One of the more predominant power quality events is the voltage sag, which is a reduction in the rmsvoltage magnitude below a given threshold*lasting typically from several cycles to several seconds . It iswidely known that voltage sags can have a strong impact on high-tech industries.EPRl has reported that asingle voltage sag can cost manufacturers from tens of thousands to as much as US $2M [B2J. Electricaland electronics equipment connected to electrical networks have varying degrees of sensitivity to voltagesags. This sensitivity is determined by two major factors: the design of the equipment and the physicalcharactcristics of the voltage sag.