GE t60 Instruction Manual page 301

5 SETTINGS
The phase directional element responds to the forward load current. In the case of a following reverse fault,
the element needs some time – in the order of 8 ms – to establish a blocking signal. Some protection ele-
NOTE
ments such as instantaneous overcurrent may respond to reverse faults before the blocking signal is
established. Therefore, a coordination time of at least 10 ms must be added to all the instantaneous protec-
tion elements under the supervision of the phase directional element. If current reversal is of a concern, a
longer delay – in the order of 20 ms – may be needed.
SETTING
PHASE DIR 1
FUNCTION:
Disabled=0
Enabled=1
SETTING
AND
PHASE DIR 1
BLOCK:
Off=0
SETTING
I 0.05 pu
PHASE DIR 1 SOURCE:
IA
Seq=ABC Seq=ACB
SETTING
VBC VCB
PHASE DIR 1 POL V
THRESHOLD:
-Use V when V
-Use V memory when
V < Min
V MINIMUM
SETTING
PHASE DIR 1 BLOCK OC
WHEN V MEM EXP:
No
Yes
PHASE B LOGIC SIMILAR TO PHASE A
PHASE C LOGIC SIMILAR TO PHASE A
GE Multilin
Min
MEMORY TIMER
1 cycle
1 sec
USE ACTUAL VOLTAGE
USE MEMORIZED VOLTAGE
Figure 5–91: PHASE DIRECTIONAL SCHEME LOGIC
T60 Transformer Protection System
SETTING
PHASE DIR 1 ECA:
RUN
AND
0
Vpol
1
I
AND
5.6 GROUPED ELEMENTS
FLEXLOGIC OPERAND
OR PH DIR1 BLK
FLEXLOGIC OPERAND
PH DIR1 BLK A
OR
FLEXLOGIC OPERAND
PH DIR1 BLK B
FLEXLOGIC OPERAND
PH DIR1 BLK C
827078A6.CDR
5-169
5