Setting Notes - Siemens SIPROTEC 7SD610 Manual

Figure 2-37 Logic diagram of the high current switch on to fault protection
2.8.2

Setting Notes

General
A precondition for using the fast tripping function is that the configuration of the device functions (Section 2.1.1)
has been set at address 124 HS/SOTF-O/C = Enabled. At address 2401 FCT HS/SOTF-O/C it can also be
switched to ON or OFF.
I>>> Stage
The magnitude of fault current which leads to the pickup of the I>>> stage is set as I>>> in address 2404.
Choose a value which is high enough for the protection not to pick up on the RMS value of the inrush current
produced during the connection of the protected object. On the other hand, fault currents flowing through the
protected object do not need to be considered.
When using a PC and DIGSI for the parameterization, the values can be optionally entered as primary or sec-
ondary quantities. For settings with secondary values, the currents will be converted for the secondary side of
the current transformers.
At address 2406 CBaux for I>>>, you can specify whether only the switch position of the local circuit
breaker is checked to release the stage (local only) or also the switch position of the circuit breaker at the
other end (local and rem.). If set to local and rem., this stage is active when the local end is energized
while the circuit breaker at the other end of the protected object is open.
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
2.8 Instantaneous High-Current Switch-onto-Fault Protection (SOTF)
Functions
97