IEEE 1564-2014 pdf download

IEEE 1564-2014 pdf download.IEEE Guide for Voltage Sag Indices.
duration (of a voltage swell): The interval between the time when the root-mean-square (rms) voltage rises above the swell threshold and the time it subsequently drops below the swell threshold.
event characteristic: A time-dependent parameter characterizing a change in voltage or current before, during, and after a voltage or current event. An event characteristic is a function of time. Event characteristics are used to detect the event, to determine the type of event, and to calculate event indices. Examples of event characteristics used for voltage sags are sliding-window root-mean-square (rms) voltage, voltage phase angle, and zero-sequence voltage (for three-phase measurements).
interruption threshold: A root-mean-square (rms) voltage value specified for the purpose of detecting the start and end of an interruption. The choice of the interruption threshold is outside of the scope of this document but should be much lower than the voltage sag threshold. Typical values are between 0% and 10% of the declared voltage or sliding-reference voltage.
NOTE—See IEC 61000-4-30.
magnitude (of a voltage sag): The minimum value of VlS(I,2) recorded during a voltage sag. The magnitude is expressed as a value in volts or as a percentage or per-unit value of the declared voltage or sliding-reference voltage.
magnitude (of a voltage swell): The maximum value of the sliding-window rms voltage VS(I2) recorded during a voltage swell. The magnitude is expressed as a value in volts or as a percentage or per-unit value of the declared voltage or the sliding-reference voltage.
retained voltage: See: magnitude (of a voltage sag).
root-mean-square (rms) variation: A term often used to express a variation in the rms value of a voltage
or current measurement from the nominal.
NOTE—Sec IEEE Std 1159.
SARFI-X: For X less than 100, the system average rms variation frequency index (SARFI) is the count of voltage sags at a given site, or in a given system, per year with a magnitude less than X percent. For X more than 100: the count of voltage swells at a given site, or in a given system, per year with a magnitude greater than X percent. For X a predefined curve: the count of voltage sags at a given site, or in a given system. per year more severe than the curve limits.
short-duration root-mean-square (rms) variation: A variation of the rms value of the voltage or current from the nominal for a time greater than 0.5 cycles of the power frequency but less than or equal to 1 mm. When the rms variation is voltage, it can be further described using a modifier indicating the magnitude of a voltage variation (e.g., sag, swell, interruption) and possibly a modifier indicating the duration of the variation (e.g., instantaneous, momentary, temporary).
NOTE—See IEEE Std 1159.
single-event characteristic: A parameter indicating the severity of a voltage or current event, or otherwise describing the event. Each type of event has specific single-event characteristics. The most commonly used single-event characteristics for voltage sags and swells are magnitude and duration.
single-site index: A parameter indicating the voltage or current quality or a certain aspect of voltage or current quality at a specific site. Single-site indices typically give the monitored or expected count or rate of events within a given period. The term “index” may be used where its meaning is clear from the context.
sliding-reference voltage: A voltage magnitude averaged over a specified time interval, representing the voltage preceding a voltage sag.
sliding-window rms voltage: The value of the rms voltage measured over one cycle and refreshed each half cycle.
system index: A parameter indicating the voltage or current quality or a certain aspect of voltage or current quality for a whole or part of a power system. System indices may be an average or a weighted average of the single-site indices obtained for all or a number of sites within the system. The term “index” may be used where its meaning is clear from the context.
voltage dip: See: voltage sag.
voltage sag energy: A single-event characteristic defined from the rms voltage versus time. The voltage sag energy has the unit of time; it may be expressed in cycles, milliseconds, or seconds.