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Functions
2.11 Measures for Weak and Zero Infeed
Trip with delay
The operation of the delayed tripping is determined by three parameters:
• Address 2517 1pol. Trip enables a single-pole trip command for phase-to-ground faults if it is parame-
terised to ON
• Address 2518 1pol. with 3I0, if set to ON, allows a single-pole trip command only if also the threshold
3I0> Threshold for the zero current has been exceeded. If the threshold 3I0> Threshold is not ex-
ceeded, phase-to-ground faults do not cause a tripping. Position OFF allows a single-pole trip command
even when 3I0> Threshold is not exceeded. The time delay of „3I0> exceeded" is set at address 2513
T 3I0> Ext..
• Address 2519 3pol. Trip, if set to ON, also allows a three-pole trip command in the event of a multi-pole
pickup. In position OFF only the multi-pole pickup is reported but a three-pole trip command is not issued
(only reporting). A 1-pole or 3-pole trip command for 1-pole pickup can still be issued.
A delayed tripping stage is implemented to allow tripping of 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 trips with delay after a configured time (address 2515 TM and address 2516 TT) depending on the
set stage mode (address 2517 1pol. Trip and 2519 3pol. Trip). If no trip command is issued during a
pickup after the times 2515 TM and 2516 TT have elapsed, the voltage memory is reset and the pickup is can-
celled.
Address 2531 WI delayed allows to set delayed tripping as operating mode. With ON this stage is perma-
nently active. With the setting by receive fail, this stage will only be active when „>WI rec. OK" is not
true. With OFF this stage is permanently switched off.
To avoid erroneous 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). In addition, the relevant phases are blocked when the
distance protection function is activated.
282
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
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