Schweitzer Engineering Laboratories SEL-387E - Page 415

Date Code 20080110 Testing and Troubleshooting 10-35
SEL-387E Instruction Manual
Step 4. Purpose: Apply balanced three-phase voltage above the setting and reduce one
phase voltage until the appropriate LED illuminates.
Method: Apply balanced three-phase voltages as shown in
Figure 10.5, adjusted to
a value above the
27P1P setting. Reduce one phase voltage until the
27P1 LED illuminates. The voltage should equal the 27P1P setting ±2 V
and ±5% of setting. Repeat the test for the other two phases.
Step 5. Purpose: Repeat the test for each phase undervoltage element.
Method: Repeat Steps 1–4 for the
27P2 undervoltage element.
Step 6. Purpose: Verify the expected phase-to-phase undervoltage pickup setting.
Method: Execute the
SHOWSET command via the relay front panel or serial port
and verify the setting (i.e.,
SHO 27PP1 <Enter> ).
Step 7. Purpose: Display the appropriate Relay Word bit on the front-panel LEDs.
Method: Execute the
TARGET command (i.e., TAR F 27PP1 <Enter> ). The
SEL-387E Relay now displays the state of the undervoltage elements on
the bottom row of front-panel LEDs.
Step 8. Purpose: Apply balanced three-phase voltage above the setting and reduce one
phase voltage until the appropriate LED illuminates.
Method: Apply balanced three-phase voltages as shown in
Figure 10.5, adjusted to
a value above the
27PP1 setting. Reduce one phase voltage until the
27PP1 LED illuminates. The phase-to-phase voltage should equal the
27PP1 setting ±2 V and ±5% of setting. Repeat the test for the other two
phase-to-phase voltages.
Step 9. Purpose: Repeat the test for each phase-to-phase undervoltage element.
Method: Repeat Steps 6–8 for the
27PP2 undervoltage element.
Step 10. Purpose: Verify the expected positive sequence undervoltage pickup setting.
Method: Execute the
SHOWSET command via the relay front panel or serial port
and verify the setting (i.e.,
SHO 27V1P <Enter> ).
Step 11. Purpose: Display the appropriate Relay Word bit on the front-panel LEDs.
Method: Execute the
TARGET command (i.e., TAR F 27V1 <Enter> ). The
SEL-387E Relay now displays the state of the undervoltage elements on
the bottom row of front-panel LEDs.