Distance Relay Settings
GARD 8000 Distance Relay
RFL Electronics Inc.
Description Range
Units
Step
Default
Directional line characteristic angle (quad)
Characteristic line angle in degrees for the directional element for
the quadrilateral characteristic. It is typically set at 75 degrees. See
Description of Operation for definition of this angle.
0 - 90
deg
1
75
Lagging phase for two-phase-to-ground faults
For two-phase-to-ground faults, the leading phase-ground element
may overreach and is not allowed to measure. The lagging phase
can be allowed to operate as it will underreach and is enabled by
this setting. Two phase to ground faults will generally by detected
by phase-phase elements, but in case high resistance is expected
for these type of faults, the setting should be YES.
No - Yes
-
1
No
Polarization memory duration
This setting determines the polarization voltage memory
duration, in cycles. Recommended setting is 2 cycles.
2 - 80
Cycles 1
6
Positive sequence voltage threshold
Voltage threshold for the memory polarization. When the
measured voltage is below the set threshold, memory is used.
0.1 – 5
V
0.1
1
7.3.2
PILOT (COMMS SCHEME)
Description Range
Units
Step
Default
Open breaker carrier send
Enables open breaker carrier send. Used with Permissive schemes
(PUTT, POTT, DCUB, DTT).
No - Yes
-
1
Yes
Security time
Sets a pickup delay for a carrier receive signal. This will ensure
that no spurious carrier signal will cause a false trip at the
receiving end.
0 - 50
ms
1
0
Weak infeed undervoltage level
Sets the undervoltage threshold for Weak Infeed tripping.
15 - 70
V
0.01
45
LOP Block weak infeed
Enables block of weak infeed tripping by loss-of-potential block.
No - Yes
-
1
No
Distance pilot scheme
Selects the type of scheme used.
Step
Distance
Zone 1
Extension
PUTT
DTT
POTT
DCUB
DCB - 1
Step
Distance
Distance carrier send extend time
Sets the drop-out delay for carrier send.
0 - 200
ms
10
50
Distance extend time
Sets a coordination drop-out time delay for the carrier start signal
from the reverse blocking zone, providing transient block function.
0 - 50
ms
1
25
DCB distance coordination time
Sets the time delay for Directional Comparison Blocking (DCB)
trip signal. This is the amount of time the forward pilot zone will
wait to receive a blocking carrier signal before trip is released.
0 - 200
ms
10
50
July 21, 2009
7-9
973.334.3100
