Fluke 1742 User Manual page 31

Nominal Voltage
Select a nominal voltage from the list. If a voltage is not shown in the
list, enter a custom voltage. On energy studies, the nominal voltage is
required to determine the limits for dips, swells, and interruptions.
The nominal voltage on load studies is used to calculate the pseudo
apparent power:
nominal voltage x measured current
Nominal Frequency
Set the nominal frequency to be the same as the power line fre-
quency, 50 Hz or 60 Hz.
Voltage Ratio (only in energy studies)
Configure a ratio factor for the voltage inputs when a potential
transformer (PT) is in series with the voltage connections such as
when you want to monitor a medium-voltage network. The default
value is 1:1.
Current Range
Configure the current range of the attached sensor:
•
Auto
When set to Auto, the current range is set automatically and
depends on the measured current.
•
Low Range
Low Range is 1/10 of the nominal range of the attached current
sensor. For example, the low range of an iFlex1500-12 is 150 A.
•
High Range
High Range is the nominal range of the attached current
sensor. For example, 1500 A is the nominal range on an
iFlex1500-12.
Set the current range to Auto when you are not sure about
the maximum current during the logging session. A specific
application can require you to set the current range to a fixed
range rather than Auto. This can occur because the Auto
range is not gapless and may lose too much information in
the case of a highly fluctuating current.
Current Ratio
Configure a ratio factor for the current sensors when a current
transducer (CT) is used to measure the much higher level on the
primary side at a substation or step-down transformer that has a built-
in metering current transformer.
Use the current ratio to increase the sensitivity of the iFlex sensor.
Wrap the iFlex sensor around the primary conductor, for example 2X,
and enter a ratio factor of 0.5:1 to get correct readings. The default
value is 1:1.
Harmonics Calculation Method
Select the harmonic calculation method to apply according to
IEC 61000-4-7. The Logger applies a FFT (Fast Fourier
Transformation) every 10/12 cycles (typical 200 ms), that delivers
spectral components (bins) every 5 Hz from dc up to ½ fs. fs is the
sample frequency of the A/D converter, for example, 10.24 kHz. The
standard allows three different ways to calculate the harmonics from
these 5 Hz components: Harmonic Components, Harmonic Sub-
Groups, and Harmonic Groups.
Power Quality Logger
Instrument and Logging Setup
Note
27