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Functions
2.25 Function Control and Circuit Breaker Test
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
446
In order to avoid that an energization is detected mistakenly, the state „line open“, which precedes any energi-
zation, must apply for a minimum time (settable with the address
1133 T DELAY. SOTF ). The default setting
for this enable delay is 250 ms. This setting can only be changed using DIGSI at
Additional Settings
.
Figure 2-221 Generation of the energization signal
The line energization detection enables the distance protection, earth fault protection, time-overcurrent protec-
tion and high-current switch onto fault protection to trip without delay after energization of their line was detect-
ed.
Depending on the configuration of the distance protection, an undelayed trip command can be generated after
energization for each pickup or for pickup in zone Z1B. The stages of the earth fault protection and of the time
overcurrent protection generate an undelayed TRIP command if this was provided for in the configuration. The
switch onto fault protection is released phase-selectively and three-pole in case of manual closure after ener-
gization detection. In order to generate a trip command as quickly as possible after an energization, the fast
switch onto fault protection is released selectively for each phase already when the line is open.