Schweitzer Engineering Laboratories SEL-387E - Frequency Elements

10-36 Testing and Troubleshooting Date Code 20080110
SEL-387E Instruction Manual
Step 12. 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
27V1P setting. Reduce one phase voltage until the
27V1 LED illuminates. The positive-sequence voltage should equal the
27V1P setting ±2 V and ±5% of setting. The positive-sequence voltage,
V1 , may be calculated as (VA + VB +VC)/3 if the voltages are 120
degrees apart in proper phase rotation.
Frequency Elements
Purpose: Verify the operation of frequency elements.
Step 1 .
Connect a source of variable three-phase voltage and frequency to the relay as
shown in
Figure 10.5.
Step 2. Purpose: Verify the expected frequency pickup setting.
Method: Execute the
SHOWSET command via the relay front panel or serial port
and verify the setting (i.e.,
SHO 81D1P <Enter> ).
Step 3. Purpose: Display the appropriate Relay Word bit on the front-panel LEDs.
Method: Execute the
TARGET command (i.e., TAR F 81D1 <Enter> ). The
SEL-387E Relay now displays the state of the frequency elements on the
bottom row of front-panel LEDs.
Step 4. Purpose: Apply balanced three-phase voltage and change the frequency until the
appropriate LED illuminates.
Method: Apply balanced three-phase voltages as shown in
Figure 10.5. Change the
frequency to a value above (below) the
81D1P setting until the 81D1 LED
illuminates. The frequency should equal the
81D1P setting ±0.01 Hz.
Step 5. Purpose: Repeat the test for each frequency element.
Method: Repeat Steps 1–4 for
81D2P through 81D6P elements.
Step 6. Purpose: Verify the expected frequency time delay setting.
Method: Execute the
SHOWSET command via the relay front panel or serial port
and verify the setting (i.e.,
SHO 81D1D <Enter> ).
Step 7. Purpose: Display the appropriate Relay Word bit on the front-panel LEDs.
Method: Execute the
TARGET command (i.e., TAR F 81D1T <Enter> ). The
SEL-387E Relay now displays the state of the frequency time-delayed
elements on the bottom row of front-panel LEDs.