Voltage sag monitoring
The voltage sag monitor compares the voltage regulator
load voltage with a reference value and determines if the
load voltage has dropped below a defined threshold level
for a defined period of time. The concept is based on the
voltage quality curve defined by the Computer Business
Equipment Manufacturer’s Association (CBEMA), which is
meant as a guideline for the kind of voltage deviation that
electronic equipment should withstand without failure. This
feature as applied to the voltage regulator will be a limited
subset of the CBEMA guideline.
With the feature enabled, the control compares the current
load voltage against three unique voltage sag set points,
with each set point containing both a voltage level (as
a percent of the reference voltage) and minimum time
duration of the voltage sag. When the control detects that
the regulated voltage has fallen below the defined voltage
level and stayed below that level for the defined duration,
the control records the voltage sag as an event in the
sequence of events recorder.
When the load voltage rises above a defined recovery
voltage for a defined recovery period of time, the control
resets the voltage sag monitor and records another event
indicating that the voltage sag has ended. A date and time
stamped record of the duration of the last and longest
voltage sag for each voltage sag level is also recorded.
The reference voltage used to compare against the
regulator load voltage is the Demand Metering value of
Forward Load Voltage Present or Reverse Load Voltage
Present as applicable.
Voltage sag monitor settings can be found using control
nested menu FEATURES > Voltage Sag Monitoring or by
accessing FC 600-606, 611-616, 621-262, 631, and 632. The
feature can also be programmed and data viewed using
ProView NXG software.
Figure 55 . Setting the voltage sag monitor using ProView NXG software
155
INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS
MN225003EN April 2018
CL-7 Voltage Regulator Control