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Logging
voltage waveform data provides additional information for analysis of the system’s
power quality or a power quality event.
When your system’s nominal parameters are programmed into the meter, power
quality events such as sags, swells and transients are automatically detected and
voltage and current waveform data is logged. The default factory settings for sag/
swell and transient detection are sufficient for most applications, but you can also
modify the amount of deviation from the nominal required to trigger waveform
recording.
Waveform data storage format
Your meter’s waveform data storage format is defined by:
• Cycles: the number of cycles included in the waveform (its duration).
• Samples: samples per cycle, which is the number of waveform data points
collected in each cycle.
This gives you the option to record a lot of information for a very short duration or
less information over a longer duration. You can also configure the waveform
recording to record pre-event and post-event data.
Types of waveform data
You can use your meter to detect ITI (CBEMA) - type disturbances, and can
determine information regarding the magnitude and duration of each disturbance.
This information can be used by your energy management system to plot the
disturbance on an ITI (CBEMA) curve.
COMTRADE waveform data is available from your meter.
NOTE: If you are generating COMTRADE waveform information, the
associated waveform recorders cannot be modified unless COMTRADE is
disabled. If the waveform recorders are not configured identically,
COMTRADE waveform information will not be generated.
Key terms
Term Definition
COMTRADE COMmon format for TRAnsient Data Exchange (COMTRADE) is a common
format for waveform data.
ITI (CBEMA) A curve that graphically describes an AC input voltage envelope which can be
typically tolerated by information technology equipment. Meter waveform
information is plotted on this curve to help evaluate power quality.
Nominal The normal or usual parameter value. For example, the nominal voltage for
many power systems is 120 V.
Sag A power event where the voltage or current drops below the nominal value.
Swell A power event where the voltage or current rises above the nominal value.
Transient A power event where a short duration surge of electrical energy is detected.
See the ION Reference, available from www.usa.siemens.com/pds, for more
information on the Waveform Recorder module and its settings.
Related Topics
• Default waveform recording configuration
Default waveform recording configuration
The meter’s default framework includes factory-configured waveform logs
(waveform recorders).
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