Table 1148: Special conditions
Condition Description
U3P connected to real meas-
urements
The function can work with any two phase voltage channels
connected but it is recommended to connect all three volt-
age channels.
Improper analog channel configuration causes a validation error if the analog
channels are not completely configured or they do not match with certain settings.
For troubleshooting, check the contents of this chapter and also the preprocessing
blocks in this document. The configuration can be written to the protection relay
once the mismatch is corrected.
5.7.5 Operation principle
The function can be enabled or disabled with the
Operation
setting. The
corresponding parameter values are "on" and "off".
The operation of SCEFRFLO can be described with a module diagram. All the
modules in the diagram are explained in the next sections.
BLOCK
TRIGG_T
Phase
selection
logic
Fault
impedance
and
distance
calculation
TRIGG_REC
ALARM
Trigger
detection
Alarm
indication
I3P
I_A
I_B
I_C
U3P
URES
U_A_AB
U
2
U
1
U
0
U_B_BC
U_C_CA
Recorded
data
TRIGG_XC0F
Figure 682: Functional module diagram
The fault distance calculation is done in two steps. First, the fault type is
determined with the in-built Phase selection logic (PSL). Second, based on the
selected impedance measuring element (fault loop) the fault distance from the
measuring point to the fault location is calculated.
The phase current magnitude's minimum threshold value is 1 % xIn.
1MRS759142 F
Protection related functions
REX640
Technical Manual
1195
To Next Page
Loading...
