GE D90 Plus Instruction Manual page 286

CONTROL ELEMENTS
278
The operand is asserted by the autorecloser 1.5 cycles after single-pole
AR FORCE 3-P TRIP
reclosing is initiated. This operand calls for a three-pole trip if any protection element
configured under with this setting remains picked-up. The open pole detector provides
blocking inputs to distance elements; as such, the distance elements will immediately
reset after the
TRIP 1-POLE
single-pole tripping, the user must ensure they reset immediately after tripping;
otherwise they will be detected as an evolving fault if they remained picked up and the
relay will execute a three-pole trip.
For example, if a high-set phase instantaneous overcurrent is used (
set to "PHASE IOC1 OP"), then the
of the instantaneous overcurrent element. In this case, after tripping phase A, the phase
A instantaneous overcurrent element is forced to reset. Phases B and C will remain
operational and can detect an evolving fault as soon as 8 ms after tripping phase A. The
neutral and negative-sequence instantaneous overcurrent elements shall be blocked
from the
OPEN POLE BLK N
prevent pickup during single-pole reclosing.
Trip Reclose Input 1, Trip Reclose Input 2, Trip Reclose Input 3, Trip Reclose Input 4, Trip
Reclose Input 5, Trip Reclose Input 6
Range: any FlexLogic™ operand or shared operand
Default: OFF
These settings selects an operand representing a fault condition that is desired to initiate
three pole reclosing (for example, phase distance zone 1). Use an OR-gate if more than
six inputs are required.
Trip Force 3-Pole
Range: any FlexLogic™ operand or shared operand
Default: OFF
This setting selects an operand that will force an input selected for single-pole operation
to produce a three-pole operation. The
recommended value for this setting. Power system configurations or conditions which
require such operations may also be considered.
Trip Pilot Priority
Range: 0 to 65.535 seconds in steps of 0.001
Default: 0.000 seconds
This setting specifies an interval equal to the inter-relay channel communications time,
plus an appropriate margin, during which outputs are not asserted. This delay permits
fault identification information from a remote terminal to be used instead of local data
only.
Reverse Fault
Range: any FlexLogic™ operand or shared operand
Default: OFF
This setting should be used to guarantee accuracy of single-pole tripping under evolving
external to internal faults. When a close-in external fault occurs, the relay is biased
toward very fast operation on a following internal fault. This is primarily due to
depressed voltages and elevated currents in response to the first, external fault. The
phase selector may exhibit some time lag compared to the main protection elements.
This may potentially result in a spurious three-pole operation on a single-line-to-ground
internal fault. Delaying tripping on internal faults that follow detection of reverse faults
solves the problem.
As long as the operand selected with this setting remains asserted, the trip action will be
delayed by the time specified by the
operand should combine reverse zone indications (such as zone 4 pickup) with a half-
cycle pickup delay, and a two-cycle dropout delay. This setting should be used only in
operand is asserted. For other protection elements used in
operand is used for blocking phase A
OPEN POLE OP ?A
operand unless the pickup setting is sufficiently large to
FlexLogic™ operand is the
AR DISABLED
Trip Delay on Evolving Faults
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 7: PROTECTION
is
Trip 1-Pole Input 1
setting. Typically, this