Functions
2.2 Phase Comparison Protection and Ground Differential Protection
SIPROTEC, 7SD80, Manual
E50417-G1140-C474-A1, Release date 09.2011
72
Depending on the way used for controlling the test mode, either the indication „Test 87 ON/off“ (no. 3199)
or „Test 87 ONoffBI“ (no. 3200) is generated. The way used for deactivating the test mode always has to
be identical to the way used for activating. The indication „Test 87“ (no. 3190) is generated independently
of the chosen way. When deactivating the test mode via the binary inputs, a time delay of 500 ms becomes
effective.
The following figures show possible variants for controlling the binary inputs. If a switch is used for the control
(Figure 2-19), it has to be observed that binary input „>Test 87 ON“ (no. 3197) is parameterized as NO
contact and that binary input „>Test 87 OFF“ (no. 3198) is parameterized as NC contact.
Figure 2-18 External push-button wiring for controlling the differential protection test mode
Bu1 Push-button „Switching off the differential protection test mode“
Bu2 Push-button „Switching on the differential protection test mode“
Figure 2-19 External switch wiring for controlling the differential protection test mode
S Switch „Switching the differential protection test mode on/off“
1) Binary input as make contact
2) Binary input as break contact
If a test switch is to be used for changing to test mode, we recommend the following procedure:
• Block the differential protection via a binary input.
• Use the test switch to activate/deactivate the test mode.
• Reset the blocking of the differential protection via the binary input.
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