1745
Users Manual
32
Current Harmonics
Current harmonics are defined as current components that have a frequency
that is an integer multiple of the fundamental frequency of the line power
current. Logging function A records ech individual harmonic of the phase
currents and the neutral current, up to the 50
th
order, and presents the
harmonics as absolute values. The values are averaged over the interval length
defined in PQ Log.
Mains Signaling
Voltage components that have frequencies hat are not integer multiples of the
fundamental frequency of the line power voltage are called Mains Signaling
voltages or ripple-control voltages (“interharmonics”). The Logger can be
programmed to record up to five interharmonics with a resolution of 5 Hz. This
function can also be used to monitor ripple-control signals by entering the
signal frequency of the local utility.
The Logger measures the three second RMS value of each interharmonic and
establishes statistics for EN50160 (European standard) evaluation. These
statistics are available after a minimum recording time of 24 hours, or after
regular termination of the measuring job and can be exported from PQ Log and
evaluated later.
Additionally, the Logger provides a long term recording of the interharmonics.
You can select from the following special measurement methods in the PQ
Log software:
•
200 ms maximum value (recommended for estimating ripple-control
signal levels)
•
200 ms minimum value
•
3 seconds maximum value
•
Average value over interval
In PQ Log, the frequency can be entered with a resolution of 0.5 Hz, but for
evaluation, the values are corrected to a bandwidth of 5 Hz. One frequency can
be defined for each band: for example, for a ripple-control signal of 183 Hz,
the values will be corrected to 185 Hz). Interharmonics of voltages and
currents with these frequencies are recorded.
See the PQ Log manual for details.
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