ABB RELION REX640 - Page 1390

methods of calculation. If Ageing rate method is set to "IEC", the relative ageing rate
is calculated as shown in Equation 334 .
V
IEC
h
=
−
( )
2
98
6
θ
(Equation 334)
If the setting Ageing rate method is set to "IEEE", the ageing rate is calculated as
shown in Equation 335 .
V e
IEEE
h
=
+
−
+
15000
110 273
15000
273 θ
(Equation 335)
Where
V
IEC
Momentary ageing rate as per IEC method
V
IEEE
Momentary ageing rate as per IEEE method
θ
h
The calculated hot-spot temperature
If the setting Insul paper type is set to "Upgraded", the IEEE method is
used for calculating the ageing rate irrespective of the value of Ageing
rate method setting.
The calculated value of the relative ageing rate, AGEING_RATE is given as an output
in the Monitored data view.
The module also calculates the average ageing rate, AVG_AGE_RATE, over a specified
time period given by the
Avg Age rate period setting. The setting Avg Age rate
period can be set to "DAY", "WEEK", "MONTH" or "YEAR".
For example, if the Avg Age rate period is set to "MONTH", the output
AVG_AGE_RATE is updated every day with the average ageing rate since the day
the calculation started. Once a month is completed, the AVG_AGE_RATE is calculated
over the previous 30 days. That is, after the 31st day, the average ageing rate is
calculated from day 2 to day 31 and so on.
If the Avg Age rate period is set to "DAY", "WEEK" or "MONTH", the calculated
AVG_AGE_RATE is refreshed every day at 12:00 hours, but if it is set to "YEAR", the
AVG_AGE_RATE is refreshed once in 30 days.
The calculated AVG_AGE_RATE is given as an output in the Monitored data view.
The function considers month as 30 days and correspondingly a year as
12 months or 360 days.
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
= ⋅
(Equation 336)
Condition monitoring functions
1MRS759142 F
1390 REX640
Technical Manual