Learning the Lingo: Standard IEEE Terminology

Engineers hear and use many terms associated with power-quality issues, but there is often confusion as to the precise meaning of the common words and phrases. Some of the more common ones-brownout, transient, spike, surge and dip-are inaccurate and do not adequately reflect the true duration and magnitude of power-quality disturbances.

01/01/2001


Engineers hear and use many terms associated with power-quality issues, but there is often confusion as to the precise meaning of the common words and phrases. Some of the more common ones-brownout, transient, spike, surge and dip-are inaccurate and do not adequately reflect the true duration and magnitude of power-quality disturbances. The definitions of the terms as used in IEEE 1159 are as follows:

  • Transient. An increase in voltage of up to eight times the nominal voltage level of very short duration, on the order of microseconds.

 

  • Instantaneous voltage sag or swell. A decrease (sag) or increase (swell) in voltage that lasts from 0.5 to 30 cycles with a magnitude of 0.1 to 0.9 times the nominal voltage levels.

 

  • Momentary voltage sag or swell. A decrease or increase in voltage generally having the same magnitudes as the instantaneous events, but with a duration of from 30 cycles to 3 seconds.

 

  • Temporary voltage interruption. A complete loss of voltage lasting from 3 seconds to one minute.

 

  • Sustained undervoltage. A decrease in voltage of between 0.8 and 0.9 times the nominal voltage for a period greater than one minute.

IEEE 1159-1995: Characteristics of Electromagnetic Phenomena


CategoryTypical DurationTypical Magnitude

Transients

Impulsive

nsec. to msec.

na

Oscillatory

3 msec. - 5 usec.

0-8 per unit (pu)

Short-Duration Variations

Instantaneous Sag

0.5-30 cycles

0.1-0.9 pu

Instantaneous Swell

0.5-30 cycles

1.1-1.8 pu

Momentary Interruption

0.5 cycles-3 sec.

less than 0.1 pu

Momentary Sag

30 cycles-3 sec.

0.1-0.9 pu

Momentary Swell

30 cycles-3 sec.

1.1-1.4 pu

Temporary Interruption

3 sec.-1 min.

less than 0.1 pu

Temporary Sag

3 sec.-1 min.

0.1-0.9 pu

Temporary Swell

3 sec.-1 min.

1.1-1.4 pu

Long-Duration Variations

Sustained Interruption

& gt;1 min.

0.0 pu

Undervoltage

& gt;1 min.

0.8-0.9 pu

Overvoltage

& gt;1 min.

1.1-1.2 pu

Voltage Imbalance

steady state

0.5-2%

Waveform Distortion

DC Offset

steady state

0.0-0.1%

Harmonics

steady state

0-20%

Inter-harmonics

steady state

0-2%

Notching

steady state

na

Noise

steady state

0-1%

Voltage Fluctuations

intermittent

0.1-7%

Power Frequency Variations

&10 sec.

na





Consulting-Specifying Engineer's Product of the Year (POY) contest is the premier award for new products in the HVAC, fire, electrical, and...
Consulting-Specifying Engineer magazine is dedicated to encouraging and recognizing the most talented young individuals...
The MEP Giants program lists the top mechanical, electrical, plumbing, and fire protection engineering firms in the United States.
How to use IPD; 2017 Commissioning Giants; CFDs and harmonic mitigation; Eight steps to determine plumbing system requirements
2017 MEP Giants; Mergers and acquisitions report; ASHRAE 62.1; LEED v4 updates and tips; Understanding overcurrent protection
Integrating electrical and HVAC for energy efficiency; Mixed-use buildings; ASHRAE 90.4; Wireless fire alarms assessment and challenges
Power system design for high-performance buildings; mitigating arc flash hazards
Transformers; Electrical system design; Selecting and sizing transformers; Grounded and ungrounded system design, Paralleling generator systems
Commissioning electrical systems; Designing emergency and standby generator systems; VFDs in high-performance buildings
As brand protection manager for Eaton’s Electrical Sector, Tom Grace oversees counterfeit awareness...
Amara Rozgus is chief editor and content manager of Consulting-Specifier Engineer magazine.
IEEE power industry experts bring their combined experience in the electrical power industry...
Michael Heinsdorf, P.E., LEED AP, CDT is an Engineering Specification Writer at ARCOM MasterSpec.
Automation Engineer; Wood Group
System Integrator; Cross Integrated Systems Group
Fire & Life Safety Engineer; Technip USA Inc.
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
click me