Schweitzer Engineering Laboratories SEL-700G Series, Instruction Manual

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4.70
SEL-700G Relay Instruction Manual Date Code 20170814
Protection and Logic Functions
Group Settings (SET Command)
➤
When 24CCS := I, the element operates with a simple inverse-
time characteristic, defined by the 24IP, 24IC and 24ITD settings
described previously.
➤
When 24CCS := U, the element operates with a user-defined
inverse-time characteristic with a pickup of 24IP. The user curve
should be set with SEL-5806 Curve Designer Software. This
program handles individual mapping of points to make a curve
that matches any transformer characteristic. It also handles all
relay communication by either uploading the current curve or
programming a new curve.
The 24CR setting defines the composite element reset time. When the element
times out to trip, it fully resets 24CR seconds after the applied volts/hertz
drops below the element pickup setting. The reset characteristic is linear, so if
the element times 60 percent toward a trip, it fully resets (0.6 • 24CR) seconds
after the applied volts/hertz drops below the element pickup setting. When the
element is reset, the relay asserts the 24CR Relay Word bit.
Both volts/hertz elements are disabled when the 24TC SEL
OGIC
control
equation equals logical 0. The elements are allowed to operate when the 24TC
SEL
OGIC
control equation equals logical 1, the default setting. You can add
other supervisory conditions if you need these for your application.
NOTE:
If 24CCS := U and no user
curve is uploaded to the relay, the
relay uses the curve corresponding
to 24IC := 2.