a-eberle REG-D, Operating Manual, Page: 23 / 52

SETUP Page 23
5.1.1.5 Overview of the IEC standard settings
D
istrib
u
ti
o
n
tran
sfo
rm
ers
Medium and large power transformers
ON
AN
ON
AN
*
limit
ed
o
il flo
w
ON
AN
ON
AF
*
limit
ed
o
il flo
w
ON
AF
OFXX
*
limit
ed
o
il flo
w
OFXX OD
X
X
Hot spot gradient Hgr [K] 23 26 26 26 26 22 22 29
Winding exponent
IEC 60354
y 1,6 1,6 1,6 1,6 1,6 1,6 1,6 2,0
Winding exponent
IEC 60076-7
y 1,6 1,3 1,3 1,3 1,3 1,3 1,3 2,0
Constant
IEC 60076-7
k
11
1,0 0,5 0,5 0,5 0,5 1,0 1,0 1,0
Constant
IEC 60076-7
k
21
1,0 3,0 2,0 3,0 2,0 1,45 1,3 1,0
Constant
IEC 60076-7
k
22
2,0 2,0 2,0 2,0 2,0 1,0 1,0 1,0
Winding time constant

w [min] 4 10 10 7 7 7 7 7
Table 1: IEC standard settings for monitoring parameters
* The information „limited oil flow“ in the above shown table is related to the oil flow
through the winding. If a winding of an ON or OF cooled transformer is zigzag-cooled, a ra-
dial spacer thickness of less than 3 mm might cause a restricted oil circulation. This fact is
taken into account in the IEC 60076 algorithm.
Constants for the IEC 60076 algorithm
The constants k
11
, k
21
and k
22
for the IEC 60076 algorithm are automatically selected by the
cooling type settings. There is no need to set them manually.