ABB Relion 650 Series Product Manual page 54

Transformer protection RET650
Version 1.1 ANSI
Table 66. Inverse time characteristics for residual overvoltage protection
Function
Type A curve:
td
=
t
æ ö
-
V VPickup
ç ÷
è ø
VPickup
EQUATION1661 V1 EN-US
V = V
measured
Type B curve:
×
td 480
=
t
æ ö
-
V VPickup
× -
ç 32 0.5 ÷
è ø
VPickup
EQUATION1662 V1 EN-US
Type C curve:
×
td 480
=
t
æ ö
-
V VPickup
ç × - ÷
32 0.5
è ø
VPickup
EQUATION1663 V1 EN-US
54
Range or value
td = (0.05-1.10) in steps
of 0.01
td = (0.05-1.10) in steps
of 0.01
2.0
-
0.035
td = (0.05-1.10) in steps
of 0.01
3.0
-
0.035
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Accuracy
Class 5 +40 ms
1MRK 504 127-BUS B
ABB Power Grids