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Date Code 20020129
Testing and Troubleshooting
10-41
SEL-387E Instruction Manual
Step 22.
Purpose: Display the appropriate Relay Word bit on the front-panel LEDs.
Method: Execute
the
TARGET
command (i.e.,
TAR F 24C2T<ENTER>
). The
SEL-387E Relay now displays the state of the volts/hertz elements on the
bottom row of front-panel LEDs.
Step 23.
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
24IP
setting until the
24C2T
LED
illuminates. Refer to
3: Differential, Overcurrent, Voltage, and
Frequency Elements
for the maximum inverse-time timing error.
Calculate pickup time as:
IC
24
1
%
100
IP
24
10
•
V
NFREQ
•
freq
PTR
•
V
•
3
ITD
24
T
2
C
24
3
nom
sec
Ü
Ü
Ü
Ü
Ü
Ü
Ý
Û
Ì
Ì
Ì
Ì
Ì
Ì
Í
Ë
-
=
V
sec
=
Secondary voltage (applied)
PTR
=
Potential transformer ratio (Setting)
Freq = Frequency
(applied)
NFREQ
=
Nominal Frequency (Setting)
V
nom
=
Nominal Voltage in kV (Setting)
24ITD
=
Inverse time factor (Setting)
24IP
=
Inverse time pickup (Setting)
24IC
=
Inverse time curve (Setting)
Step 24.
Purpose: Verify the Level 2 volts/hertz delay reset setting.
Method: Execute
the
SHOWSET
command via the relay front panel or serial port
and verify the setting (i.e.,
SHO 24CR<ENTER>
).
Step 25.
Purpose: Display the appropriate Relay Word bit on the front-panel LEDs.
Method: Execute
the
TARGET
command (i.e.,
TAR F 24CR<ENTER>
). The
SEL-387E Relay now displays the state of the volts/hertz elements on the
bottom row of front-panel LEDs.