13-18 BE1-951 Testing and Maintenance 9328900990 Rev L
Instantaneous Overcurrent (50T)
50TP/150TP and TN (Calculated 3Io) Pickup and Dropout Verification
Purpose: To verify the accuracy of the operation of the 50TP/150TP and TN (3Io) elements.
Reference Commands: SL-50T/150T, SL-GROUP, SL-VO
Step 1: Connect a current source to Terminals D1 and D2 (A-phase). Refer to
Figure 13-1 for terminal
locations. An ohmmeter or continuity tester may be used to monitor output contact status.
Step 2: Prepare the 50T/150T elements for testing by transmitting the commands in
Table 13-6 to the
relay. Reset targets.
Table 13-6. 50T Pickup Test Commands
Command Purpose
A= Gains write access.
SL-N=NONE Zero out custom logic settings. Overwrite with logic=none settings.
Y Confirm overwrite.
SL-N=PU50 Sets PU50 as custom logic name.
SL-50T=1,0 Enables 50TP, 50TN (3Io), and 50TQ and disables blocking.
SL-VO1=50TPT Enables OUT1 to close for 50TP trip.
SL-VO2=50TNT Enables OUT2 to close for 50TN trip.
SG-CT=1 Sets P, N CT ratio at 1:1
SG- TRIG=50TPT+50TNT,
50TPPU+50TNPU,0
Enable 50TPT or 50TNT to log and trigger fault recording.
EXIT;Y Exit and save settings.
Step 3: Using
Table 13-7 as a guide, transmit the low range setting commands (minimum pickup
setting) for your sensing input type.
Table 13-7. 50T Pickup Settings
Pickup Settings Commands
Current
Sensing
Input Type
Ranges
Phase Neutral
Purpose
Low S0-50TP=0.5,0,N S0-50TN=0.5,0,N
Sets 50T PU at 0.5 A, TD = 0,
non-directional.
Middle S0-50TP=5.0,0,N S0-50TN=5.0,0,N
Sets 50T PU at 5.0 A, TD = 0,
non-directional.
5 A
High S0-50TP=25.0,0,N S0-50TN=25.0,0,N
Sets 50T PU at 25.0 A, TD = 0,
non-directional.
Low S0-50TP=0.1,0,N S0-50TN=0.1,0,N
Sets 50T PU at 0.1 A, TD = 0,
non-directional.
Middle S0-50TP=1.0,0,N S0-50TN=1.0,0,N
Sets 50T PU at 1.0 A, TD = 0,
non-directional.
1 A
High S0-50TP=5.0,0,N S0-50TN=5.0,0,N
Sets 50T PU at 5.0 A, TD = 0,
non-directional.
Step 4: Slowly increase the A-phase current until OUT1 closes. Verify that pickup occurs within the
specified accuracy listed in
Table 13-8. Slowly decrease the applied current until OUT1 opens.
Dropout should occur at 93 to 97 percent of pickup.
Step 5: Repeat Step 4 while monitoring OUT2 (50TN enabled for 3Io). Verify 50TA and 50TN targets on
the HMI.
Step 6: Repeat Steps 4 and 5 for the middle and high range pickup settings for your sensing input type.
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