Siemens SIPROTEC 7SD610 User Manual

Functions
2.9 Backup Time Overcurrent Protection
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
107
Inverse time overcurrent stage I
P
The logic of the inverse overcurrent stage also operates chiefly in the same way as the remaining stages. How-
ever, the time delay is calculated here based on the type of the set characteristic, the intensity of the current
and a time multiplier (following figure). A pre-selection of the available characteristics was already carried out
during the configuration of the protection functions. Furthermore, an additional constant time delay T Ip Add
or T 3I0p Add may be selected, which is added to the inverse time. The possible characteristics are shown
in the Technical Data.
The following figure shows the logic diagram. The setting parameter addresses of the IEC characteristics are
shown by way of an example. In the setting information (Section 2.9.3) the different setting addresses are elab-
orated upon.

Siemens SIPROTEC 7SD610 Specifications

General

Brand	Siemens
Model	SIPROTEC 7SD610
Category	Relays
Language	English