GE C60 Instruction Manual page 409

CHAPTER 5: SETTINGS
and
START TMR Z2GR Inp1 START TMR Z2GR Inp2
timer to avoid a trip delay if the fault evolves from one zone of protection to another zone of protection (for example, from
zone 3 to zone 2). For instance, the
OR-gate if more than two inputs are required. See the ground distance logic diagrams for information.
— This setting specifies the reset delay of the Phase Selector element outputs after system
PH SELECTOR RST DELAY
disturbance occurs. This delay has to be long enough to allow elements assigned to cause single-pole tripping to operate.
If, for example, it is intended that distance zone 2 with a time delay of 0.5 seconds causes a single-pole trip, then this
setting has to be at least 0.6 seconds.
— This setting selects an operand to reset the Phase Selector element. The selected operand is ORed
PH SELECTOR RESET
with the operand internally to reset the phase selector element. See the Phase Selection section in the Theory
OPEN POLE OP
of Operation chapter for details.
— Selects an operand that forces an input selected for single pole operation to produce a three-pole
TRIP FORCE 3-POLE
operation. The FlexLogic operand is the recommended value for this setting. Power system configurations or
AR DISABLED
conditions that require such operations can be considered as well.
— This setting is used to set an interval equal to the inter-relay channel communications time, plus a
TRIP PILOT PRIORITY
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.
— Use this setting to guarantee accuracy of single-pole tripping under evolving external to internal faults.
REVERSE FAULT
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 can
exhibit some time lag compared to the main protection elements. This can 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 indicated under this setting is asserted the trip action is delayed by
time. Typically this operand should combine reverse zone indications (such as zone 4 pickup) with a half-cycle pickup delay,
and two-cycle dropout delay. Use this setting only in single-pole tripping applications, when evolving faults are of
importance, and slightly delayed operation on evolving faults can be traded for enhanced accuracy of single-pole tripping.
— Use this setting in conjunction with the preceding
TRIP DELAY ON EVOLV FAULTS
is set around half a power system cycle. Use it only in single-pole tripping applications, when evolving faults are of
importance, and slightly delayed operation on evolving faults can be traded for enhanced accuracy of single-pole tripping.
, , and
BKR ΦA OPEN BKR ΦB OPEN
C of the breaker is open, respectively.
C60 BREAKER PROTECTION SYSTEM – INSTRUCTION MANUAL
— These settings select an operand that starts the ground distance zone 2
FlexLogic operand can be assigned to these settings. Use a FlexLogic
GND DIST Z3 PKP
— These settings are used to select an operand to indicates that phase A, B, or
BKR ΦC OPEN
CONTROL ELEMENTS
TRIP DELAY ON EVOLV FAULTS
setting. Typically this value
REVERSE FAULT
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