CYG PRS-7367 - Protection Principle

Protection Functions
PRS-7367 43
Signal
Description
Op_B
This is the operation signal of phase B
Op_C
This is the operation signal of phase C
Alm
This is the integrated Alarm signal
3.3.2 67P Protection Principle
Each stage of the protection function can be enabled or disabled by setting the corresponding
67P_Ena parameter values as "1" or "0".
The operation of directional overcurrent protection can be described using a module diagram. All
the modules in the diagram are explained in the next sections.
 PTS Alarm Blocking of 67P
The PTS alarm can be set by PTS_Blk setting, if PTS_Blk=1 and the PTS Alm signal is 1, the 67P
function will be blocked, including the startup, trip and the timer will be reset; when if PTS_Blk=0
and the PTS Alm signal is 1, the VCE element and the Direction function will be valid, the 67P
function will become the Non directional overcurrent.
Debouncing time
Validate the change
of binary input state
& write it into SOE
record
Invalidate the
change of binary
input state
Figure 3.3-2 PTS Alarm Open and Block Condition
 Voltage Control Element (VCE) of 67P
In this part of 67P, the Voltage Control Element determines the line voltage or negative sequence
voltage, when any phase line voltage is less than the setting value of low voltage or the negative
sequence voltage is greater than the setting value of negative sequence voltage. Then the 67P
VCE condition is fulfilled.
Uab<67P_Low_VolANA
U2>67P_Neg_VolANA
67P_Vol_EnaSET
Ubc<67P_Low_VolANA
Uca<67P_Low_VolANA
1
67P_VCE_Str
FLG
&
67P_Neg_Vol _Ena=1SET
1
Figure 3.3-3 The Initiation Logic Diagram VCE Start
 Directional element