GE Industrial Solutions Pulsar Plus Controller - Manual (Page 168)

Pulsar Plus Controller Family
Issue 7 December 2011 168
longer operating as a redundant power system. An additional rectifier may be required to ensure continuous
redundant operation.
If enabled, this feature will be disabled during battery discharge and recharge conditions. It will be enabled
when the battery charging current falls below 5A.
Battery Voltage Imbalance Detection
This feature requires the use of the ES771A Remote Voltage Monitoring Module. Note that this feature is
automatically enabled if the controller detects the presence of the ES771A module. This module is to be
placed in the electronics cabinet and utilizes the QS873A VT-Probes to measure the voltage of the battery
string being monitored. The VT-Probe is to be placed on the negative battery terminal located in the middle
of the battery string. The controller has data on the plant voltage; the half-string voltage measured from
each monitored battery string is compared to the plant voltage minus the measured half-string voltage. If
the comparison results in a difference of greater than 1.7V (or the configured value) for longer than 12
hours, the alarm is asserted. The alarm may be retired by initiating the Clear Events command from the
front panel.
After this feature has been enabled, the system waits for 12 hours to ensure the battery strings are stable. A
battery string is considered to be stable if the charging current is less than 3A. If a stable battery string yields
a difference measurement greater than 1.7V (or the configured value) for over 12 continuous hours, a
Battery Voltage Imbalance alarm is generated.
When the alarm is issued, the Float Set-Point (fsp) and the Battery On Discharge (BD) threshold values are
reduced by fsp/Number of Cells per string. Once the alarm has been cleared by the Clear Events (CLE)
command, the plant reverts to its normal Float Set-Point (fsp); however, the BD threshold is maintained at
the new threshold for up to four minutes before reverting back to the old threshold. This is done to ensure
the batteries have had enough time to charge up to the nominal fsp and to prevent any spurious BD alarm
conditions.
This feature may be used by customers as part of their overall battery maintenance program in determining
the health of battery strings. A voltage imbalance of 1.7V between half-string voltages may mean a shorted-
cell, loose connection, or some other abnormality somewhere in the string. A service person should be sent
out to the site and determine if the string should be replaced.
Battery Recharge Current Limit
The battery recharge current limit feature enables the controller to limit the recharge current flowing into a
battery section during the charge cycle. The recharge current flowing into the battery section can be limited
to any value between 5A and 1000A.
Note that this feature will not have any impact on the current being delivered to the load. Further, there will
be no effect on the discharge current flowing from the battery strings to the load during an ac fail condition.
The controller will maintain the recharge current within 10% of the set level.
Battery Parameter Defaults
The controller has been configured with battery specific defaults. These battery types are shown in the top
portion of Table C-1 Supported Battery Types. The generic Valve –Regulated Lead Acid battery is the default
battery type for this controller configuration. Battery models and their parameters can be added or adjusted
in the field.