Schweitzer Engineering Laboratories SEL-387E - Volts;Hertz Elements

Date Code 20080110 Testing and Troubleshooting 10-37
SEL-387E Instruction Manual
Step 8. 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. The 81D1T LED
should illuminate
81D1D seconds later, within ±0.0042 seconds and
±0.1% of setting.
Step 9. Purpose: Repeat the test for each frequency element.
Method: Repeat Steps 6–8 for the
81D2D through 81D6D frequency time-delayed
element.
Volts/Hertz Elements
Purpose: Verify the operation of volts/hertz elements.
Step 1 . Method: Connect a source of variable three-phase voltage and frequency to the
relay as shown in
Figure 10.5.
Step 2. Purpose: Verify the Level 1 volts/hertz pickup setting.
Method: Execute the
SHOWSET command via the relay front panel or serial port
and verify the setting (i.e.,
SHO 24D1P <Enter> ).
Step 3. Purpose: Display the appropriate Relay Word bit on the front-panel LEDs.
Method: Execute the
TARGET command (i.e., TAR F 24D1 <Enter> ). The
SEL-387E Relay now displays the state of the volts/hertz elements on the
bottom row of front-panel LEDs.
Step 4. Purpose: Apply balanced three-phase voltage and change the voltage until the
appropriate LED illuminates.
Method: Apply balanced three-phase voltages as shown in
Figure 10.5. Change the
voltage to a value above the
24D1P setting until the 24D1 LED
illuminates. The
24D1 pickup should be ± 1% of setting. Calculate
pickup voltage as:
NFREQ•PTR•3
V•freq•P1D24•10
V
nom
sec
=
V
sec
= Secondary Voltage (applied)
PTR = Potential transformer ratio (Setting)
freq = Frequency (applied)
NFREQ= Nominal Frequency (Setting)
V
nom
= Nominal Voltage in kV (Setting)