Rockwell Automation 1426 PowerMonitor 5000 Unit - Manual (Page 88)

88 Rockwell Automation Publication 1426-UM001F-EN-P - November 2013
Chapter 5 Power Quality Monitoring
Waveform Distortion
(Category 5.1 - DC Offset, and
5.2 - Harmonics) (M6 model) The PowerMonitor 5000 M6 model detects and reports long-term waveform
distortion in excess of configured limits. Categories 5.3, 5.4 and 5.5 are not
supported in the M6 model.
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
Operation
The M6 model measures voltage and current THD, over the specified rolling
average interval and annunciates if these THD 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 the
CTs do not pass DC. DC offset is measured on directly-connected voltage
channels and is tracked in the power quality log.
Status
These status bits annunciate over limit conditions and remain asserted until the
parameter is no longer over the threshold. A value of 1 indicates over limit. They
are found in the Status.Alarms tab.
• IEEE1159_DCOffset_Condition_V1
• IEEE1159_DCOffset_Condition_V2
• IEEE1159_DCOffset_Condition_V3
• IEEE1159_Voltage_THD_Condition_V1
• IEEE1159_Voltage_THD_Condition_V2
• IEEE1159_Voltage_THD_Condition_V3
• IEEE1159_Current_THD_Condition_ I1
• IEEE1159_Current_THD_Condition_ I2
• IEEE1159_Current_THD_Condition_ I3