Monitored Data; Operation Principle; Technical Data; Four Step Residual Overcurrent Protection, Zero, Negative Sequence Direction Ef4Ptoc - ABB RET650 Technical Manual

Section 8
Current protection
8.3.6
8.3.7
8.3.8
8.4
154

Monitored data

Table 83: EFPIOC Monitored data
Name Type
IN REAL

Operation principle

The sampled analog residual currents are pre-processed in a discrete Fourier filter
(DFT) block. From the fundamental frequency components of the residual current, as
well as from the sample values the equivalent RMS value is derived. This current
value is fed to the Instantaneous residual overcurrent protection (EFPIOC). In a
comparator the RMS value is compared to the set operation current value of the
function (IN>>). If the residual current is larger than the set operation current a signal
from the comparator is set to true. This signal will, without delay, activate the output
signal TRIP.

Technical data

Table 84: EFPIOC technical data
Function
Operate current
Reset ratio
Operate time
Reset time
Critical impulse time
Operate time
Reset time
Critical impulse time
Dynamic overreach
Four step residual overcurrent protection, zero,
negative sequence direction EF4PTOC
Values (Range) Unit
- A
Range or value
(1-2500)% of lBase
> 95%
20 ms typically at 0 to 2 x I
set
30 ms typically at 2 to 0 x I
set
10 ms typically at 0 to 2 x I
set
10 ms typically at 0 to 5x I
set
40 ms typically at 5 to 0x I
set
2 ms typically at 0 to 5 x I
set
< 5% at t = 100 ms
1MRK 504 135-UEN A
Description
Residual current
Accuracy
± 1.0% of I at I £ I
r r
± 1.0% of I at I > I
r
-
-
-
-
-
-
-
-
Technical manual