GE UR Series L90, Инструкция по эксплуатации

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GE Multilin L90 Line Current Differential System 10-21
10 APPLICATION OF SETTINGS 10.5 PROTECTION SIGNALING SCHEMES
10
c) LOSS-OF-GUARD OPERATION
The loss-of-guard operation picks under the following conditions:
• The scheme is enabled (
DCUB FUNCTION
is “Enabled” and
DCUB BLOCK
is “Off”), and
• any loss-of-guard signal is received without its associated
RX
signal, and
• a fault is seen in the forward zone 2 distance elements or ground directional forward function (if configured), and
• the reverse zone 4 distance elements or ground directional reverse function (if configured) did not pickup to set the
transient blocking.
If these conditions are met, then the
DCUB LOG PICKUP DELAY
timer is started. After this timer times out, the trip table is run,
operating the scheme and asserting the
DCUB OP
FlexLogic operand. The trip table with the aid of the local phase selector
and loss-of-guard signals will determine what tripping operands will be operated. The
DCUB LOG PICKUP DELAY
timer allows
for any and all channel(s) to transition from guard to permissive before operating due to loss-of-guard in the presence of a
forward fault. The time window of allowing the scheme to operate when no
DCUB RX
signal is received when any loss-of-
guard was received is the difference between the
DCUB LOG TRIP WINDOW
and
DCUB LOG PICKUP DELAY
timers. When using
default settings, this value is 150 – 8 = 142ms. This means the scheme is unblocked and can trip during this time window if
a forward fault is sensed.
d) KEYING OF THE CARRIER(S) UNDER NORMAL CONDITIONS
The keying signals, which allows the relay to key the permissive channel during normal permissive scheme operation by
means of the
DCUB TX1
through
DCUB TX4
signals, are established as follows:
• The scheme is enabled (
DCUB FUNCTION
is “Enabled” and
DCUB BLOCK
is “Off”), and
• a fault is seen in the forward zone 2 distance elements or ground directional forward function (if configured), and
• the reverse zone 4 distance elements or ground directional reverse function (if configured) did not pickup to set the
transient blocking.
If these conditions are met, then the scheme will key the channel(s) by means of asserting transmit signals
DCUB TX1
through
DCUB TX4
with the aid of the local phase selector or zone 2 distance elements.
e) KEYING OF THE CARRIER DURING ECHO CONDITIONS
The echo signal, which allows the relay to key the permissive channel(s) through the
DCUB TX1
through
DCUB TX4
transmit
operands during echo conditions when the local breaker opened, will key the carrier(s) during the following conditions:
• The scheme is enabled (
DCUB FUNCTION
is “Enabled” and
DCUB BLOCK
is “Off”), and
• the
DCUB PERMISSIVE ECHO
setting is “Enabled”, and
• the
LINE PICKUP LEO PKP
operand that detects the local breaker to be open picks up for a time set by
LINE END OPEN
PICKUP DELAY
, and
• any permissive signal
DCUB RX1
through
DCUB RX4
is received and any
LOG1
to
LOG4
is received, and
• a fault is not seen in the forward zone 2 distance elements or ground directional forward function (if configured) for at
least 100 ms, and
• the reverse zone 4 distance elements or ground directional reverse function (if configured) did not pickup to set the
transient blocking.
If these conditions are met, then the scheme will echo (transmit the
DCUB TX1
through
DCUB TX4
operands) the received
permissive
DCUB RX
signal(s) back to the remote relay based on the echo table.
The keying or transmit signals
DCUB TX1
through
DCUB TX4
consist of all normal keying or echo keying conditions.
The scheme
DCUB TRIP A
,
DCUB TRIB B
,
DCUB TRIP C
, and
DCUB TRIP 3P
output operands are hard-wired to the trip output
scheme. As such, if the trip output or breaker control operands (if the breaker control function is used) are used for tripping,
the scheme fully operational. The permissive key carrier signals
DCUB TX1
through
DCUB TX4
must still be assigned to the
tripping/operating logic, and to output contacts as per the usual L90 logic/output assignments.