9424200994 Rev N 489
Step 5: Slowly increase the magnitude of the IG current input until OUT2 closes and record the pickup.
This should occur at 5.0 A ±0.05 A. Verify that there is an 87N-1 target on the front-panel
display.
Step 6: Reset the currents according to step 4. Reset all targets.
Step 7: To verify directional blocking of the 87N-1 element, slowly increase the magnitude of the A-
phase current input until the magnitude reaches 5.1 A. Verify that Iop is greater than 2.0 A and
that OUT2 remains open.
Step 8: To verify the operation of the directional bias and the overcorrection coefficient, slowly increase
the angle of the A-phase current input until OUT2 closes. This should occur at approximately
64°.
Step 9: Reset the currents according to step 4. Reset all targets.
Step 10: Slowly decrease the magnitude of the A-phase current input until OUT2 closes and record the
pickup. This should occur at 1.0 A ±0.05 A. Verify that there is an 87N-1 target on the front-
panel display.
Step 11: (Optional.) Repeat steps 1 through 10 for CT input 2 and IG2.
Step 12: (Optional.) Repeat steps 1 through 11 for settings group 1, 2, and 3.
Timing Verification
Step 1: Use BESTCOMSPlus to verify the operational settings in Table 221 and logic in Figure 309.
Reset all targets.
Step 2: Prepare to monitor the 87 timings. Timing accuracy is verified by measuring the elapsed time
between OUT2 (pickup) and OUT1 (trip) closing.
Step 3: Connect a single-phase current source to terminals D1 and D2 (CT1 A-phase): 1.0 A ∠0°.
Connect a single-phase current source to terminals D7 and D8 (IG input): 1.0 A ∠180°.
Step 4: Step the IG current input to 4.0 A ∠180° and verify that OUT2 closes. Record the time between
OUT2 and OUT1 closing. This should be 100 ms ±50 ms.
Step 5: Reset IG input to 1.0 A ∠180°. Reset all targets.
Step 6: (Optional) Repeat steps 1 through 5 for settings group 1, 2, and 3.
Functional Test Report
Pickup Verification
Pickup Setting Range = 0.1 - 5 A
Pickup Accuracy = ±0.05 A
Timing Verification
Time Delay Range = 50 to 60,000 ms
Timing Accuracy = ±0.5% or ±2 cycles, whichever is greater
BE1-11g Neutral Current Differential (87N) Test