Dranetz PowerGuide 4400, Руководство пользователя

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Journal Interval for Timed Readings
Journal Interval for Timed Readings
Introduction
The Journal Interval screen allows users to define how often the 4400 saves data
periodically, regardless of power quality disturbances and journal limits.
Definitions
Power Values
Power Values Interval
- Power parameter values are based upon all cycles during a one
second interval. Data is aggregated or summarized into min, max and avg values over
the averaging period and stored at the end of the interval. Data measured include watts,
power factors, as well as the one-second rms (not to be confused with the one cycle
rms). Cyclic min, max and avg are based upon full cycle waveforms with a resolution
of one half (1/2) cycle. They record the rms, crest, and waveshape parameters that are
also used to capture a snapshot of the waveform. Note that if users did not set the
thresholds for rms variations properly, the min, max and avg will still provide a record
of what happened during the interval.
Waveform Snapshot
- Contains properties that measure periodic sample or snapshot of
the voltage and/or current waveform. Users are able to determine how often the
instrument will record waveform snapshots by turning the function on or off.
Demand and Energy
Demand Sub-Interval
and
Sub-Intervals per Interval
- Refer to the time interval used in
calculating power demand values. Demand calculations are made every sub-interval on
the values that occurred during the most recent Demand Interval. Values set for
Demand Sub-Interval must be an integer-divisor of the Demand Interval since the
former applies when updating certain parameters of the latter.
Harmonics
Harmonics Journal Interval -
Various harmonic parameters such as total harmonic
distortion (THD), total interharmonic distortion (TID), and telephone influence factor
(TIF) can be trended using periodic readings that are stored in the journal. Depending
on the harmonic journal interval set, the instrument records a sampling of the waveform
synchronized to the fundamental frequency, to ensure accurate calculation of harmonic
phase angles.
Flicker
Pst (Short Term) Interval
- Pst is short term perceptibility, used to set the Pst calculation
interval. Typical calculation is over a 10-minute interval, though users can specify Pst
Interval under Flicker.
Plt (Long Term) Interval -
Plt is long term perceptibility, used to set the Plt calculation
interval. Typical calculation is over a 2-hour interval, though users can specify Plt
Interval under Flicker.
The Plt interval must be an integer multiple of the Pst interval. Sliding Plt recalculates
the Plt value at each Pst interval, rather than only at the Plt interval.
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