Functions
2.2 Phase Comparison Protection and Ground Differential Protection
SIPROTEC, 7SD80, Manual
E50417-G1140-C474-A1, Release date 09.2011
71
2.2.7 Differential Protection Test and Commissioning
2.2.7.1 Differential Protection Test
General
If differential protection test mode (test mode in the following) is activated, the differential protection is blocked
in the entire system. Depending on the configuration, the overcurrent protection acts 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 measuring the thresholds of the differential protection. Moreover, the test mode prevents in the local
device that tripping of the differential protection generates a transfer trip signal.
The test mode can be activated/deactivated as follows:
• Operation panel: Menu Control/Taggings/Set: „Test mode“
• Via binary inputs (no. 3197 „>Test 87 ON“, no. 3198 „>Test 87 OFF“) if this was routed
• In DIGSI with Control / Taggings: „Diff: Test mode“
The test mode status of the other device of the line protection system is indicated on the local device by the
indication „Test 87 remote“ (No. 3192).
Mode of Operation
Below, the logic is shown in a simplified way:
Figure 2-17 Logic diagram of the test mode
32126 87N L block OUT 87N L: Protection is blocked
32127 87N L OFF OUT 87N L: Protection is switched off
32128 87N L 3V0> OUT 87N L: detection 3V0> pickup
32129 87N L Forward OUT 87N L: detection Forward
32130 87N L Reverse OUT 87N L: detection Reverse
32131 87N L UndefDir OUT 87N L: detection Undef. Direction
32132 87N L rec. blk OUT 87N L: receive blocking
32133 87N L send blk OUT 87N L: send blocking
32134 87N L PU OUT 87N L: pickup
32150 87L ISTAT> C OUT 87L ISTAT> C
No. Information Type of In-
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