ABB Relion SMU615 Technical Manual page 166

Section 6
Condition monitoring functions
160
A071109 V2 EN
Figure 112: Functional module diagram for calculating accumulative energy and
alarm
Accumulated energy calculator
This module calculates the accumulated energy I
the Current exponent setting.
The calculation is initiated with the POSCLOSE input opening events. It ends when
the RMS current becomes lower than the Acc stop current setting value.
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Figure 113: Significance of the Difference Cor time setting
The Difference Cor time setting is used instead of the auxiliary contact to accumulate
the energy from the time the main contact opens. If the setting is positive, the
calculation of energy starts after the auxiliary contact has opened and when the delay
is equal to the value set with the Difference Cor time setting. When the setting is
negative, the calculation starts in advance by the correction time before the auxiliary
contact opens.
The accumulated energy outputs IPOW_A (_B, _C) are available in the monitored
data view on the WHMI or through tools via communications. The values can be reset
by setting the parameter CB accum. currents power setting to true in the clear menu
from WHMI.
Alarm limit check
The IPOW_ALM alarm is activated when the accumulated energy exceeds the value
set with the Alm Acc currents Pwr threshold setting. However, when the energy
1MRS758407 B
y y
t [(kA) s]. The factor y is set with
Technical Manual
SMU615