Schweitzer Engineering Laboratories SEL-387E - Page 414

10-34 Testing and Troubleshooting Date Code 20080110
SEL-387E Instruction Manual
Step 14. Purpose: Display the appropriate Relay Word bit on the front-panel LEDs.
Method: Execute the
TARGET command (i.e., TAR F 59Q <Enter> ). The
SEL-387E Relay now displays the state of the overvoltage elements on
the bottom row of front-panel LEDs.
Step 15. Purpose: Apply balanced three-phase voltage below the setting and raise one phase
voltage until the appropriate LED illuminates.
Method: Apply balanced three-phase voltages as shown in
Figure 10.5. Raise one
phase voltage until the
59Q LED illuminates. The negative-sequence
voltage,
V2 , should equal the 59QP setting ±2 V and ±5% of setting. The
negative-sequence voltage may be calculated as (VA + a
2
VB +aVC)/3
where a = 1 ∠120.
Step 16. Purpose: Verify the expected residual overvoltage pickup setting.
Method: Execute the
SHOWSET command via the relay front panel or serial port
and verify the setting (i.e.,
SHO 59G1P <Enter> ).
Step 17. Purpose: Display the appropriate Relay Word bit on the front-panel LEDs.
Method: Execute the
TARGET command (i.e., TAR F 59G1 <Enter> ). The
SEL-387E Relay now displays the state of the overvoltage elements on
the bottom row of front-panel LEDs.
Step 18. Purpose: Apply balanced three-phase voltage below the setting and raise one phase
voltage until the appropriate LED illuminates.
Method: Apply balanced three-phase voltages as shown in
Figure 10.5. Raise one
phase voltage until the
59G1 LED illuminates. The residual voltage, V0 ,
should equal the
59G1P setting ±2 V and ±5% of setting. The residual
voltage may be calculated as the vector sum (VA + VB +VC)/3.
Step 19. Purpose: Repeat the test for each residual overvoltage element.
Method: Repeat Steps 16–18 for the
59G2 overvoltage element.
Verify the operation of undervoltage elements.
Step 1. Connect a source of variable three-phase voltage to the relay as shown in Figure
10.5.
Step 2. Purpose: Verify the expected phase undervoltage pickup setting.
Method: Execute the
SHOWSET command via the relay front panel or serial port
and verify the setting (i.e.,
SHO 27P1P <Enter> ).
Step 3. Purpose: Display the appropriate Relay Word bit on the front-panel LEDs.
Method: Execute the
TARGET command (i.e., TAR F 27P1 <Enter> ). The
SEL-387E Relay now displays the state of the undervoltage elements on
the bottom row of front-panel LEDs.