Date Code 20080110 Protection Functions 3-67
SEL-387E Instruction Manual
The 24IC setting defines the curve shape.
Level 2 Inverse-Time Factor (24ITD)
Range
: 0.10–10.0 s
The 24ITD setting defines the inverse element operate time in seconds when the transformer
volts/hertz equals 200 percent.
When 24CCS = U:
The element operates with a user-defined inverse-time characteristic. The user curve should be
set using SEL-5806 PC 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.
Level 2 Inverse-Time Pickup (24IP)
Range
: 100–200%
The 24IP setting defines the pickup point of the user-defined operating time curve. The
SEL-387E Relay asserts the 24C2 Relay Word bit without time delay when the transformer
volts/hertz exceeds the 24IP setting. The relay asserts the 24C2T Relay Word bit in time defined
by the user-defined curve when the measured apparatus volts/hertz exceeds the user-defined
setting.
When 24CCS = DD, ID, I, or U:
Level 2 Reset Time (24CR)
Range:
0.04–400.00 s
The 24CR setting defines the composite element reset time. When the element times out to trip,
it will fully reset 24CR seconds after the applied volts/hertz drops below the element pickup
setting. The element reset characteristic is linear, so if the element times 60 percent toward a trip,
it will fully reset (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.
24 Element Torque Control (24TC)
Range
: SEL
OGIC
control equation
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.
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