Functions
2.2 Protection Data Interfaces and Protection Data Topology
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
81
Figure 2-13 Principle and preferred external button wiring for controlling in the "Log out device" mode
Bu1 Button „Log on device“
Bu2 Button „Log out device“
Figure 2-13 shows the preferred variant for changing the “Log out device” mode with the aid of two buttons.
The used binary inputs are to be used as NO contacts.
2.2.2.2 Differential Protection Test Mode
General
If the differential protection test mode (test mode in the following) is activated, the differential protection is
blocked in the entire system. Depending on the parameter settings, either the distance protection assumes the
entire protection function over all zones or the time overcurrent protection becomes effective as emergency
function.
In the local device, all currents from the other devices are set to zero. The local device only evaluates the locally
measured currents, interprets them as differential current but does not send them to the other devices. This
enables to measure the thresholds of the differential protection. Moreover, the test mode prevents the genera-
tion of an intertrip signal in the local device by tripping of the differential protection.
If the device is still connected to the local CT the measured current can lead to a trip of the device.
If the device was logged out of the line protection system before activating the test mode (see “Log out device”
mode), the differential protection remains effective in the other devices. The local device can now also be
tested.
The test mode can be activated/deactivated as follows:
• Using the integrated keypad: Menu Control/Taggings/Set: „Test mode“
• Via binary inputs (No. 3197 „>Test Diff. ON“, No. 3198 „>Test Diff. OFF“) if this was allocated
• In DIGSI with Control/Taggings: „Diff: Test mode“
The test mode status of another device of the line protection system is indicated on the local device with the
indication „TestDiff.remote“ (No. 3192).
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