CYG PRS-7367 - SOTF Protection Principle

Protection Functions
60 PRS-7367
I3P
OCT_SOTF
BlkOp
CB_CLOSE
BISTART
BISTADLY
Str
Op
U3P
Figure 3.6-1 Function block
3.6.1.2 Signals
Table 3.6-1 Input Signals
Signal
Description
U3P
The voltage in all the three phases
I3P
The current magnitude in all the three phases
Blk _Op
This signal blocks all the trip signals of the function.
CB_CLOSE
The CB close signal
BISTART
The start from function to be accelerated by SOTF.
BISTADLY
The start from function to be accelerated with delay by SOTF
Table 3.6-2 Output Signals
Signal
Description
Str
This is the integrated start signal
Op
This is the integrated operation signal.
Alm
This is the integrated Alarm signal
3.6.2 SOTF Protection Principle
The automatic switch-onto-fault protection function can be enabled or disabled by setting the
corresponding SOTF_Ena parameter values as "1" or "0".
The operation of automatic switch-onto-fault logic can be described by using a module diagram.
All the modules in the diagram are explained in the next sections.
 External Start
This module is used for detecting a possible fault immediately after circuit breaker closing. The
use of external protection function (typically the start-signal from a non-directional distance zone or