ABB RET670 Product Manual page 54

Transformer protection RET670 ANSI
Pre-configured
Product version: 1.2
Table 28. Four step residual overcurrent protection EF4PTOC (51N/67N)
Function
Operate current
Reset ratio
Operate current for directional
comparison
Timers
Inverse characteristics, see table
78, table 79 and table 80
Second harmonic restrain
operation
Relay characteristic angle
Minimum polarizing voltage
Minimum polarizing current
Real part of source Z used for
current polarization
Imaginary part of source Z used
for current polarization
Operate time, pickup function
Reset time, pickup function
Critical impulse time
Impulse margin time
54
Range or value
lBase
(1-2500)% of
> 95%
lBase
(1–100)% of
(0.000-60.000) s
18 curve types
(5–100)% of fundamental
(-180 to 180) degrees
VBase
(1–100)% of
IBase
(1-30)% of
(0.50-1000.00) W/phase
(0.50–3000.00) W/phase
25 ms typically at 0 to 2 x I
set
25 ms typically at 2 to 0 x I
set
10 ms typically at 0 to 2 x I
set
15 ms typically
1MRK 504 118-BUS A
Accuracy
± 1.0% of I at I £ I
n n
± 1.0% of I at I > I
n
-
± 1.0% of I
n
± 0.5% ±10 ms
See table 78, table 79 and table
80
± 2.0% of I
n
± 2.0 degrees
± 0.5% of V
n
±0.25% of I
n
-
-
-
-
-
-
ABB