ABB RELION REX640 Technical Manual page 1286

Section 7
Condition monitoring functions
1280
Loss of life calculation
The momentary loss of life can be calculated as the product of the momentary ageing
rate and the time step over which the momentary ageing is calculated.
DL V Dt
= ⋅
n n
GUID-01F45138-EB6F-4202-9A55-C54BBD957B9D V1 EN
The total loss of life is the sum of the momentary loss of life and the total loss of life
until time, n-1.
L L DL
= +
n n n
−1
GUID-A0DE9CCF-ACA4-4A0A-8B77-BFB8E5BB5A6E V1 EN
The initial loss of life L
For new transformer installations, the Initial loss of life setting should
be "0". For previously installed transformers, the Initial loss of life can
be set to the consumed transformer life in months.
The calculated value of the loss of life in years, LOSS_OF_LIFE, is given as an
output in the Monitored data view.
The calculated value of LOSS_OF_LIFE can be reset through the input RESET.
Level detector 2
This module compares the ALM_AGE_RATE output with the setting Alarm level Age
Rte.
If the calculated AVG_AGE_RATE over the Avg Age rate period setting is greater than
Alarm level Age Rte, the module activates the binary output ALM_AGE_RATE.
The binary input RST_AVGAGING can be used to reset the output ALM_AGE_RATE
and also the calculated value of AVG_AGE_RATE.
Once the RST_AVGAGING input is active, the average ageing rate values stored over
the Avg Age rate period setting is erased and the calculation of AVG_AGE_RATE is
restarted.
If the Avg Age rate period is set to "YEAR", the output
AVG_AGE_RATE is refreshed once in 30 days starting from the time
the relay is installed or since the last activation of binary input
RST_AVGAGING.
The activation of the BLOCK input deactivates the ALM_AGE_RATE output.
, is taken from the setting Initial loss of life.
0
1MRS759142 C
(Equation 301)
(Equation 302)
REX640
Technical Manual