468 Rockwell Automation Publication 1426-UM001J-EN-P - August 2019
Appendix G IEEE 1159 Power Quality Event Classification
Waveform Distortion
(Categories 5.1 - DC Offset,
5.2 - Harmonics, and 5.3 -
Interharmonics)
The power monitor detects and reports long-term waveform distortion in excess
of configured limits. Table 14 on page 103
indicates which phenomena are
supported by the PowerMonitor 5000 models.
Setup
Basic metering setup required. These configuration parameters are found in the
Configuration.PowerQuality tab:
• IEEE1159_DCOffsetAndHarmonics_Averaging_Intvl_m - rolling
average interval for DC offset and harmonics, range = 1
…15 minutes,
default = 5 minutes
• IEEE1159_Voltage_DCOffset_Limit_% - DC offset alarm threshold,
range = 0.00
…1.00 per cent of fundamental, default = 0.1 per cent
• IEEE1159_Voltage_THD_Limit_% - voltage THD alarm threshold,
range = 0.00
… 20.00 per cent of fundamental, default = 5 per cent
• IEEE1159_Current_THD_Limit_% -current THD alarm threshold,
range = 0.00
…20.00 per cent of fundamental, default = 10 per cent
• IEEE1159_Voltage_TID_Limit_% - voltage TID (total interhamonic
distortion) alarm threshold, range = 0.00…20.00 per cent of fundamental,
default = 5 per cent (M8 only)
• IEEE1159_Current_TID_Limit_% - voltage TID (total interhamonic
distortion) alarm threshold, range = 0.00…20.00 per cent of fundamental,
default = 10 per cent (M8 only)
Operation
The power monitor measures voltage and current THD (and the M8 model
measures TID), over the specified rolling average interval and annunciates if
these values exceed the specified thresholds. The rolling average is updated at a
rate of 10 seconds per minute of the specified interval.
The PowerMonitor 5000 unit does not measure current DC offset because CTs
do not pass DC. DC offset is measured on directly connected voltage channels
and is tracked in the power quality log.
To Next Page
Loading...
