Basler Electric BE1-51/27C - Manual (Page 61)

9137200998 Rev E 55
Step 3. Set the front panel INST 1 control to a position approximating the desired instantaneous 1
overcurrent pickup point for the relay.
Step 4. Apply current to the relay.
Step 5. Rapidly increase the overcurrent input to the relay until the instantaneous output relay just
energizes. Note the overcurrent threshold reading on the ammeter.
Step 6. Remove input current.
Step 7. Reset the INST TARGET (if present).
Step 8. If the overcurrent threshold reading from Step 5 was too high or low, adjust the front panel INST
1 control CCW to lower (or CW to raise) the instantaneous 1 overcurrent pickup point. Repeat
Steps 4 through 8. If the overcurrent threshold reading from Step 5 was NOT too high or low,
proceed to Step 9.
Note
For relays with two-phase-and-neutral or three-phase-and-neutral
sensing (Sensing Input Types D, T, or J), perform Steps 9 through 14.
Step 9. Reconnect the output to the neutral current sense terminals. See Figures 32, 34, or 35.
Step 10. Set the front panel INST 1 (NEUTRAL) control to a position approximating the desired neutral
instantaneous 1 overcurrent pickup point for the relay.
Step 11. Apply current to the relay.
Step 12. Rapidly increase the overcurrent input to the relay until the instantaneous output relay just
energizes. Note the test set overcurrent threshold reading on the ammeter.
Step 13. Remove the input current.
Step 14. Reset the INST TARGET (if present).
Step 15. If the overcurrent threshold reading from Step 13 was too high or low, adjust the front panel
INST 1 (NEUTRAL) control CCW to lower (or CW to raise) the Neutral Instantaneous 1
Overcurrent Pickup Point. Repeat Steps 9 through 14. If NOT, proceed to the next test.
INST 2 Control Setting
For this adjustment, repeat INST 1 Control Setting, but substitute instantaneous 2 output terminals (11
and 12) and the front panel INST 2 controls. Because neutral sensing does not apply to this pickup point,
ignore Steps 9 through 15.
Setting the Relay
General
Neutral (ground) time overcurrent and all instantaneous overcurrent functions operate independently of
the voltage control circuits so that these elements can be set conventionally. These optional functions are
set independently of each other except that the instantaneous setting is 1 to 40 times the associated time
overcurrent element pickup.
Set the instantaneous elements pickup at least at 120 percent of the maximum current that can be seen
by the relay for an external fault where operation is not desired. Time settings for the time overcurrent
elements can be chosen as if the relay had no voltage sensing elements. This makes it easier to
coordinate with other external protection. Set the phase element pickup for about 50 percent of the rated
current for a generator backup function. Neutral time overcurrent pickup must be set above the maximum
expected normal unbalance. In addition, in the case of residually connected elements, added relay
current can result from dissimilar errors in the three current transformers. This error will be greater for the
BE1-51/27C Tests and Adjustments