Waveform recording

The meter’s factory-configured waveform recorders store waveform data related to power quality events.

Waveform information is used to help identify power system disturbances, which are an increasing concern for industrial plants, hospitals, data centers and other facilities where the equipment is sensitive to voltage or current sags, swells, and momentary interruptions. Waveform information is also used to help ensure compliance with power quality standards.

In addition to measuring and recording numerical values for voltage and current, your meter can also capture the sinusoidal waveform data. The current and 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 and swells are automatically detected and voltage and current waveform data is logged. The default factory settings for sag/swell 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 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.

For more information see Waveform Recorder Module in ION Reference help.