Date Code 20020129
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
•
P
1
D
24
•
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)
