U.6.36
SEL-421/SEL-421-1 Relay
User’s Guide
Date Code 20020501
Testing and Troubleshooting
Checking Relay Operation
Figure 6.30
Phase Distance Elements Settings:
AC
SEL
ERATOR
Software.
Step 4. Upload the new settings to the SEL-421 Relay. On the File
menu, click Send. The
AC
SEL
ERATOR
software prompts you
for the settings class you want to send to the relay, as shown in
the Group Select dialog box of
. Click
the check box for Group 1. Click OK. The
AC
SEL
ERATOR
software responds with a dialog box similar to the second
dialog box of
. If you see no error message, the new
settings are loaded in the relay.
Step 5. Display the MBC2 Relay Word bit on the front-panel LCD
screen. Access the front-panel LCD MAIN MENU. Highlight
RELAY ELEMENTS and press
{ENT}
. You will see a RELAY
ELEMENTS screen with SEARCH highlighted at the bottom
of the screen. Press
{ENT}
to go to the ELEMENT SEARCH
submenu of
. Use the navigation keys
to highlight M and press
{ENT}
to enter character in the text
input field. Enter the B, C, and 2 characters in like manner.
Highlight ACCEPT and press
{ENT}
. The relay displays the
LCD screen containing the MBC2 element, as shown in
Figure 6.31
RELAY ELEMENTS LCD Screen Containing Element MBC2.
Step 6. Set the magnitudes and angles of the test signals for a B-phase-
to-C-phase fault. Connect the test sources (with power off) to
the relay, as in
. This connection is a
B-phase-to-C-phase fault where I
A
»
0 and I
B
= –I
C
. Adjust the
voltage sources to provide the following test voltages: V
A
= 67
V
Ð
0
°
, V
B
= 46.8 V
Ð
–150
°
, and V
C
= 46.8 V
Ð
150
°
. Set the
current source for I
B
= 0.0 A
Ð
–174
°
.
Step 7. Apply the sources to confirm operation of MBC2. Apply the
source test current by slowly increasing the magnitude of I
B.
Observe the RELAY ELEMENT LCD screen. Relay Word bit
MBC2 asserts when |I
B
|
³
2.5 A, indicating that the relay
impedance calculation is less than the Z2P reach setting.
PRESS TO SEARCH
RELAY ELEMENTS
SEARCH
ROW 8
ROW 9
* =0 * =0
MCA2 =0 MCA4 =0
MBC2 =0 MBC4 =0
MAB2 =0 MAB4 =0
* =0 * =0
MCA1 =0 MCA3 =0
MBC1 =0 MBC3 =0
MAB1 =0 MAB3 =0
Содержание SEL-421
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