Eaton SC300 - Page 78

SC300 Handbook
72
Copyright © 2007-2018 Eaton Corporation. All Rights Reserved.
IPN 997-00012-03 B2 Issue B2 July 2018
Parameter Description Where to find:
Only shown if an analog input is configured as
Battery Third Quarter Point.
Imbalance The percentage imbalance of the Mid-point
Voltage, or the worst imbalance of the ¼ , mid
and ¾ point if QPM is in use.
Configuration
Set the following parameters.
Parameter Description Where to find:
String Fail alarm
parameters
See System Alarm Configuration on page 57. Web: Alarms > Alarm States
MPM Lockout
Period*
Time from when MPM is able to start until the
start of the MPM Convergence Period.
SC300: Battery > MPM >
Settings
Web: Batteries > Mid-point
Monitoring
MPM Convergence
Period*
Time from the end of the MPM Lockout Period
until MPM State is Stable. During this period the
Current MPM Threshold is calculated using linear
interpolation between Start Threshold and Stable
Threshold and the MPM State is defined as
Converging. After this period the MPM State is
defined as Stable and the MPM Stable Threshold
applies.
String Fail
Recognition Period
If the mid-point / quarter point Imbalance
percent of a battery string exceeds the MPM
Threshold for this period of time the String State is
set to Fail and the String Fail alarm is activated.
MPM Start
Threshold*
Mid-point / quarter point Imbalance percent
threshold at the start of the MPM Convergence
Period.
MPM Stable
Threshold*
Mid-point / quarter point Imbalance percent
threshold after the convergence period.
* A dynamic alarm threshold is used to give the best possible battery fault detection:
1 After the end of a discharge, Fast Charge or Equalize cycle, MPM does not start until the end of
the MPM Lockout Period, to ensure the system is in float charge.
2 At this point, the battery cell voltages are expected to be widely spread, so the alarm threshold
is set high (MPM Start Threshold).
3 The alarm threshold is then progressively reduced over the MPM Convergence Period.
4 After the end of the MPM Convergence Period, cell imbalance is assumed to be stable, and a
fixed threshold is used (MPM Stable Threshold).