2.10 Weak-infeed Tripping (optional)
257
7SD5 Manual
C53000-G1176-C169-1
Moreover, the phase-selective block signals BLOCK Weak Inf affect the non-delayed
logic. Faulty pickups are thus prevented, especially after the dedicated line end was
shut down.
In address 2530 WI non delayed the stage for instantaneous tripping is switched
OFF or ON continuously.
Trip with Delay The operation of the delayed tripping is determined by three parameters:
•Address 2517 1pol. Trip enables a single-pole trip command in case of single-
pole faults if set to ON.
• If set to ON, address 2518 1pol. with 3I0 allows a single-pole trip command
only if the threshold 3I0> Threshold for the zero current has been exceeded. If
the threshold 3I0> Threshold is not exceeded, single-pole faults do not lead to
tripping. Position OFF allows a single-pole trip command even when 3I0>
Threshold is not exceeded. The time delay for the signal „3I0> exceeded“ is set
at address 2513 T 3I0> Ext..
• If set to ON, address 2519 3pol. Trip allows also a three-pole trip command in
the event of a multi-pole pickup. In position OFF the multi-pole pickup is only report-
ed but a three-pole trip command is not issued (only report). But a single-pole or
three-pole trip command can nevertheless be issued.
A delayed tripping stage is implemented to allow tripping the dedicated line end in
case the transmission channel is faulted. When undervoltage conditions have been
detected, this stage picks up in one or more phases and after a configured time (ad-
dress 2515 TM and address 2516 TT) has elapsed it trips without delay.
Address 2531 WI delayed allows to set delayed tripping as operating mode. With
ON this stage is permanently active. With the setting by receive fail, this stage
will only be active if „>WI rec. OK“ is not reported OFF.
To avoid spurious pickup, phase selection via undervoltage is blocked entirely in the
event of voltage failure (pickup of the fuse failure monitor or of the VT mcb). Moreover,
the corresponding phases are equally blocked if another protection function, capable
to detect faults, picks up.
2.10.3 Weak Infeed Tripping (optional)
2.10.3.1 Settings
Addresses which have an appended "A" can only be changed with DIGSI, under Ad-
ditional Settings.
The table indicates region-specific presettings. Column C (configuration) indicates the
corresponding secondary nominal current of the current transformer.
Addr. Parameter C Setting Options Default Setting Comments
2501 FCT Weak Infeed OFF
ECHO only
ECHO and TRIP
ECHO only Weak Infeed function is
2502A Trip/Echo DELAY 0.00 .. 30.00 sec 0.04 sec Trip / Echo Delay after
carrier receipt
2503A Trip EXTENSION 0.00 .. 30.00 sec 0.05 sec Trip Extension / Echo
Impulse time
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