10.11
Date Code 20171006 Instruction Manual SEL-400 Series Relays
Testing, Troubleshooting, and Maintenance
Test Methods
The operating time (t
p
) for a time dial (TD) equal to 1 for the U3 (Very Inverse)
Curve is:
Equation 10.2
In this example, use QuickSet to configure the relay. You must have a computer
that is communicating with the SEL-451 and running the QuickSet (see Making
Settings Changes in Initial Global Settings on page 3.20). You also need a vari-
able current source for relay testing.
Step 1. Prepare to control the relay with QuickSet by establishing communi-
cation, checking passwords, and reading relay settings.
Step 2. Set the selectable operating quantity time-overcurrent element for
test operation.
a. Open the Group 1 > Set 1> Relay Configuration > Time Over-
current branch of the Settings tree view (see Figure 10.4).
b. Verify that enable setting E51S (Selectable Inverse-Time
Overcurrent Element) is set to 1, or greater.
c. In the Time Overcurrent dialog box, change setting 51S1O
Operating Quantity to 3I0L.
d. Change the remaining element configurations to match Table 10.4.
t
p
TD • 0.0963
3.88
M
2
1–
----------------+
=
1 • 0.0963
3.88
1.5
2
1–
-------------------+=
3.2 seconds=
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