10-40 Testing and Troubleshooting Date Code 20080110
SEL-387E Instruction Manual
Step 18.
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 19.
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 and below the
24D2P2
setting
until the
24C2T
LED illuminates. Refer to
Section 3: Protection
Functions
for the maximum inverse-time timing error. Calculate pickup
time as:
IC24
1
%100
IP24
10•V
NFREQ
•
freq
PTR•V•3
ITD24
T2C24
3
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)
24ITD = Inverse time factor (Setting)
24IP = Inverse time pickup (Setting)
24IC = Inverse time curve (Setting)
Step 20.
Purpose: Verify the
24D2P2
setting and
24D2D2
delay.
Method: Apply balanced three-phase voltages as shown in
Figure 10.5. Change the
voltage from a value below the
24IP
setting to a value above the
24D2P2
setting. The
24C2T
LED should illuminate
24D2D2
seconds later.
Step 21.
Purpose: Verify the Level 2 volts/hertz delay settings, when
24CCS = I
.
Method: Execute the
SHOWSET
command via the relay front panel or serial port
and verify the setting (i.e.,
SHO 24CCS <Enter>
).
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