ABB RELION 620 Series Technical Manual page 924

Section 7
Condition monitoring functions
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A071109 V2 EN
Figure 482: 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.
A071110 V1 EN
Figure 483: 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 LHMI or through tools via communications. The values can be reset
by setting the parameter Initial CB Rmn life setting to true in the clear menu from
WHMI or LHMI.
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
1MRS757644 F
y y
t [(kA) s]. The factor y is set with
Technical Manual
620 series