Iskra FPC 200 - Restricted Earth Fault Protection - ANSI Code 64 REF

Functionality
26 USER MANUAL FPC 200 - 3/2017
Restricted earth fault protection - ANSI code 64REF
Restricted Earth Fault function is one of advanced protection functions installed in FPC 200 protection relay. Protection
detects earth faults in power transformers, shunt reactors, neutral earthing transformers/reactors, or rotating machines.
Starpoint of protected element should be earthed. The starpoint CT and the phase CTs define the limits of absolutely
selective protection. Restricted earth fault protection is not applicable to busbar, type B of FPC 200 protection relay.
2.2.4.1 Functionality
Function compares calculated residual phase current
(3I
0
) with measured neutral point current I
e
.
Off
64 Res. Earth fault
Mode:
Enabled:
Pickup value:
0.1In
Yes
Trip delay: 2s
A
1A 1B 2A 2B
CONTROL SETTINGS
Figure 2.21 Example of parameter settings on HMI.
2.2.4.2 Delays
Function includes following delays explained in Chapter
2.1:
 Pickup delay
 Trip delay
 Drop-out delay
2.2.4.3 Connection scheme
Typical Connection scheme is shown on Figure 2.22.
L1
L2
L3
3Io=I1+I2+I3
FPC 200
Ie
I1I2I3
Figure 2.22: Connection scheme.