Appendix C Specifications
Page
4 1
The
SCOR
relay is available in single-phase, three-phase,
two
phase-with-ground, and three-phase-with-ground configura
tions, and with the features and capabilities described in
Table
C.1 .
Current Sensing Inputs
Current Sensing Burden
Frequency (nominal)
Time Overcurrent
Pickup Ranges:
Pickup Adjustment:
Pickup Setting Accuracy:
Pickup Repeatability:
Droput Ratio:
Instantaneous Overcurrent:
Pickup Range:
Pickup Setting Accuracy:
Dropout Ratio:
Table
C.1
Specifications
The unit is designed to operate from the secondary of a standard current transformer
rated at 5 A. The maximum continuous current rating for each input is five times tap or
20 A, whichever is less.
The one-second current rating for each input is 50 times tap or 500 A , whichever is
less. Ratings at less than one second are calculated as:
=
K
=
T
=
{Klf
where
(500
A or
50
times TAPt
Time that current flows (in seconds)
Less than 0.025 ohms per phase at nominal 60 Hz. (see
Table
3)
60 Hz.
Two ranges are available: HIGH (2.0 - 1 1.0 A}, and LOW (0.5 - 5.0 A). Range is
independently specified for phase and ground by the second digit of the Style
Number. The TAP range windows on the front panel indicate which range (HIGH or
LOW} is specified. Selection of the desired tap is made using the rotary selector
switch(s) on the front panel. Refer to the table on the front panel for the various tap
ratings in secondary amps.
Incrementally adjustable over the selected range by a front-panel (TAP) selector switch
("coarse"), and by numerical data entered into the Tap Cal register ("fine").
The accuracy of the pickup setting is
+1-
2% of the programmed setting over the full
specified range of the relay at 60 Hz.
Within 2%.
Better than 80% of the established pickup level within 50 milliseconds.
0.5 to 20 times the value of the time overcurrent pickup setting.
The accuracy of the instantaneous pickup setting is
+/-
2% of the programmed setting
over the full specified range of the relay at 60 Hz.
Better than 80% of the extablished pickup level within 50 milliseconds.
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