A8
Reactive power
Power that does not perform actual work, resulting in power con-
sumption as it travels between the load and the power supply.
Reactive po
wer is calculated by multiplying the active power by the
sine of the phase difference (sin
). It arises from inductive loads
(deriving from inductance) and capacitive loads (deriving from
capacitance), with reactive power derived from inductive loads
known as lag reactive power and reactive power derived from
capacitive loads known as lead reactive power.
Reactive power
demand value
The average reactive power used during a set period of interval time
(usually 30 minutes).
RMS value
The square root of the squares of 1,024 sampling points in a 200 ms
interval. The value includes harmonic components.
SD memory card A type of flash memory card.
Text data
A file containing only data expressed using characters and charac-
ter codes.
Total harmonic
distortion factor
(PW3360-21 only)
THD-F: The ratio of the size of the total harmonic component to the
size of th
e fundamental wave, expressed as a percentage using the
following equation:
THD-F =
(for the PW3360, calculated to the 40th order)
This value can be monitored to assess waveform distortion for each
ite
m
, providing a yardstick that indicates the extent to which the total
harmonic component is distorting the fundamental waveform. As a
general rule, the total distortion factor for a high-voltage system
should be 5% or less; it may be higher at the terminal point of the
system.
THD-R:
The ratio of the size of the total harmonic component to the size of
RM
S
values, expressed as a percentage using the following equa-
tion:
THD-R =
(for the PW3360, calculated to the 40th order)
THD-F is typically used.
USB
An interface that allows data to be sent to and received from a host
controller (usually a computer) to which a device is connected with a
USB cable. Consequently, functions are unable to communicate
directly.
Zero suppression
Functionality for treating values that are less than a certain thresh-
old as zero.
∑(from 2nd order)
2
Fundamental waveform
x 100 [%]
∑(from 2nd order)
2
RMS values
x 100 [%]
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