ABB Relion 650 Series Product Manual page 63

ABB
Transformer protection
RET650
Product version: 1.0
Table 63. Inverse time characteristics for Two step undervoltage protection UV2PTUV
Function
Type A curve:
k
=
t
æ ö
< -
U U
ç ÷
è ø
<
U
EQUATION1431-SMALL V1 EN
U< = U
set
U = UV
measured
Type B curve:
×
k 480
=
t
2.0
æ ö
< -
U U
ç × - ÷
32 0.5
è ø
<
U
EQUATION1432-SMALL V1 EN
U< = U
set
U = U
measured
Range or value
k = (0.05-1.10) in steps of
0.01
(Equation 7)
k = (0.05-1.10) in steps of
0.01
+
0.055
(Equation 8)
1MRK 504 110-BEN -
Issued: September 2009
Accuracy
Class 5 +40 ms
63