4
<Glossary>
Eco-POWER METER defines as below.
THD
(total harmonic
distortion)
Ratio of harmonic distortion (voltage or current) for the fundamental frequency.
Lower the value shows that the distortion is less.
Harmonics
Sinusoidal wave other than fundamental frequency.
It has frequency that is whole-number multiple of the fundamental frequency.
The frequency that has 2 times frequency (half wavelength) is called 2
nd
-order
harmonics.
Voltage
unbalancing
The different between each phase-voltage due to the load unbalancing.
It is calculated as below.
|Max. (Min.) voltage of all phase
-
average voltage|
×
100 (%)
Average voltage
Current
unbalancing
The difference between each-phase current due to the load unbalancing.
It is calculated as below.
|Max. (Min.) current of all phase
-
average current|
×
100 (%)
Average current
Power
interruption
Voltage under 5% of rating is kept 100ms or more,
Under voltage
Set the ratio for the rated voltage and it is used for threshold.
Voltage under the set ratio is kept 100ms or more, it will judge as under voltage.
Under current
Set the ratio for the rated current and it is used for threshold.
Current under the set ratio is kept 100ms or more, it will judge as under current.
Over current
Set the ratio for the rated current and it is used for threshold.
Current over the set ratio is kept 100ms or more, it will judge as over current.
Demand by
IEC61557-12
Based on IEC61557-12 Performance measuring and monitoring devices (PMD)
Sliding block interval
demand
It calculates by measured power via CT with setting interval.
Set power interval by 1 to 60(min.) (every 1-min.). It calculates demand
during latest finished interval and displays.
One interval is started every setting time.
fixed block interval
demand
It calculates by measured power via CT with setting interval.
Set power interval by 1 to 60 (min.) (every 1-min.) It calculates demand
during latest finished interval and displays. After one interval finishes, the
next interval starts.
Current demand
It calculates based on a thermal demand meter.
It measures an average current (current demand) within setting interval and
the max. value is considered as max. current demand.
30-min demand
This works for electric power input by CR or pulse.
It measures using power during 30-min. and calculates average (kW).
Max. value of 1-month is recorded and displayed.
Peak demand
Max. value of instantaneous power during 1-month is considered as a peak
demand. Peak demand of 12-month is recorded for 4 time-zones.
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