U.4.34
SEL-421 Relay User’s Guide Date Code 20090715
Basic Relay Operations
Examining Metering Quantities
Step 4. Set CT and PT ratios. Use the terminal to confirm that Group 1
setting CTRW := 200 (the current transformer W-input ratio),
and PTRY := 2000 (the potential transformer Y-input ratio).
a. Type SET CTRW TERSE <Enter>.
b. If the CTRW setting is not 200, type 200 <Enter>.
c. Proceed as shown in Figure 4.24 to PTRY and change
PTRY to 2000, if needed.
d. Type END <Enter> to finish this settings session.
e. Answer Y <Enter> to the save settings prompt.
=>>SET CTRW TERSE <Enter>
Group 1
Line Configuration
Current Transformer Ratio - Input W (1-50000) CTRW := 1000 ? 200 <Enter>
Current Transformer Ratio - Input X (1-50000) CTRX := 1000 ? <Enter>
Potential Transformer Ratio - Input Y (1-10000) PTRY := 2000 ? END <Enter>
Save settings (Y,N) ? Y <Enter>
Saving Settings, Please Wait...........
Settings Saved
=>>
Figure 4.24 Setting CTRW and PTRY: Terminal
Step 5. Turn the relay power off.
Step 6. Connect analog inputs.
a. If three voltage sources and three current sources are
available, connect the sources to the relay as shown in
Figure 4.25.
If three voltage sources and two current sources are
available, use the connection diagram of Figure 4.26.
b. Apply 67 V per phase (line-to-neutral) in ABC phase
rotation.
c. Apply 2.0 A per phase, in phase with the applied phase
voltages.
Courtesy of NationalSwitchgear.com
To Next Page
Loading...
