GE F60 Instruction Manual page 548

MONITORING ELEMENTS
This scheme is for two-terminal line applications only. It uses over-reaching directional protection elements (such as
directional overcurrent functions) to essentially compare the direction to a fault at both the ends of the line. The Line End
Open input field needs to be properly set to indicate line-end-open (LEO) / weak-infeed conditions.
POTT3 SCHEME BLOCK
5
a pilot cut-out switch are used typically for this purpose.
POTT3 PERMISSIVE ECHO
The echo is sent only once and then the logic locks out for the time specified by the
echo pulse is settable as
POTT3 RX PICKUP DELAY
longest spurious TX signal that can be received simultaneously with the protection function pickup specified in
fields. The selected delay increases the response time of the scheme.
FWD1-3
TRANS BLOCK PICKUP DELAY
with exposure of the directional overcurrent function. Upon receiving the
mechanism allows the RX signal to be passed and aligned with the
BLOCK PICKUP DELAY
BLOCK RESET DELAY
Set this
TRANS BLOCK PICKUP DELAY
not longer than the fastest possible operation time of the protection system that can create current reversal conditions
within the reach of the selected directional overcurrent function.
TRANS BLOCK RESET DELAY
with exposure of the directional overcurrent function to current reversal conditions (see the
this delay long enough to cope with transient conditions including not only current reversals but also spurious negative-
and zero-sequence currents occurring during breaker operations.
— This setting defines the guaranteed and exact duration of the echo pulse. The duration does not depend
ECHO DURATION
on the duration and shape of the received RX signal. This setting enables the relay to avoid a permanent lock-up of the
transmit/receive loop.
— This setting defines the lockout period for the echo logic after sending the echo pulse.
ECHO LOCKOUT
LINE END OPEN PICKUP DELAY
open condition is a requirement for the POTT3 scheme to return a received echo signal (if the echo feature is enabled).
POTT3 LINE END OPEN
condition, such as breaker open status, or under voltage and under current conditions.
5-334
LINE END OPEN PICKUP

DELAY: 0.050 s
LINE END OPEN:

Off
POTT3 SEAL-IN

DELAY: 0.400 s
POTT3 DIR FWD1:

Off
POTT3 DIR FWD2:

Off
POTT3 DIR FWD3:

Off
POTT3 RX:

Off
POTT3 SCHEME TARGET:

Self-Reset
POTT3 SCHEME EVENTS:

Disabled
— This setting allows any FlexLogic operand to be assigned to block the scheme. Contact inputs from
— If this setting is set to "Enabled," the scheme sends a permissive echo signal to the remote end(s).
.
ECHO DURATION
— This setting enables the relay to cope with spurious receive signals. Set the delay longer than the
— This setting defines a transient blocking mechanism embedded in the POTT3 scheme to cope
. After that the ground directional overcurrent path is virtually disabled for the time specified as
.
long enough to give the selected directional overcurrent function time to operate, but
— This setting defines a transient blocking mechanism embedded in the POTT3 scheme to cope
— This setting defines the pickup delay of the line end open conditions. The validated line end
— This setting allows the user to select the FlexLogic operand to represent the Line End Open
Range: 0.000 to 65.535 s in steps of 0.001
Range: FlexLogic operand
Range: 0.000 to 65.535 s in steps of 0.001
Range: FlexLogic operand
Range: FlexLogic operand
Range: FlexLogic operand
Range: FlexLogic operand
Range: Self-Reset, Latched, Disabled
Range: Disabled, Enabled
ECHO LOCKOUT
signal, the transient blocking
POTT3 RX
indication for a period of time set by
DIR FWD1-3
TRANS BLOCK PICKUP DELAY
F60 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
. The duration of the
POTT3 DIR
TRANS
TRANS
). Set