Operating Modes Of The Differential Protection; Mode: Log Out Device - Siemens SIPROTEC 7SD610 Manual

2.2.2

Operating Modes of the Differential Protection

2.2.2.1 Mode: Log Out Device

General
The „Log out device" mode (also: Log out device functionally) is used to log the device out of the line protection
system with the local circuit breaker being switched off.
The remaining device continues to operate in "differential protection mode", the special feature, however, being
that only the locally measured currents are included in the logic as differential currents. The behaviour is now
comparable to a time overcurrent protection. The set thresholds for the differential current now evaluate the
local current.
A device can be logged out and on as described below:
• Using the integrated keypad: Menu Control/Taggings/Set: „Logout"
• Via DIGSI: Control / Taggings „Logout local device"
• Via binary inputs (No. 3452 „>Logout ON", No. 3453 „>Logout OFF") if this was allocated
In the other device of the line protection system, logging out/on of a device is signalled by the indications
„Rel1Logout" or „Rel2Logout" (No. 3475 or No. 3476).
Principle of function
In the following, the logic is shown in a simplified way:
Figure 2-6 Logic diagram for switching the "Log out device" mode
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
2.2 Protection Data Interfaces and Protection Data Topology
Functions
53