3-28 Overcurrent, Voltage, Synchronism Check, Frequency, and Power Elements Date Code 20001006
SEL-351 Instruction Manual
Settings Ranges
Table 3.6: Negative-Sequence Time-Overcurrent Element Settings
Setting Definition Range
51QP pickup 0.50 - 16.00 A secondary (5 A nominal phase current
inputs, IA, IB, IC)
0.10 - 3.20 A secondary (1 A nominal phase current
inputs, IA, IB, IC)
51QC curve type U1 - U5 (US curves) see Figure 9.1 - Figure 9.10
C1 - C5 (IEC curves)
51QTD time dial 0.50 - 15.00 (US curves) see Figure 9.1 - Figure 9.10
0.05 - 1.00 (IEC curves)
51QRS electromechanical
reset timing
Y, N
51QTC SELOGIC Control
Equation torque
control setting
Relay Word bits referenced in Table 9.3
or
set directly to logical 1 (= 1) or logical 0 (= 0) - see
note below
Note: If SELOGIC Control Equation torque control setting 51QTC is set directly to logical 0 (i.e.,
51QTC = 0), then corresponding negative-sequence time-overcurrent element 51QT is
defeated and nonoperational, regardless of any other setting.
See Section 9: Setting the Relay for additional time-overcurrent element setting information.
Accuracy
Pickup: ±0.05 A secondary and ±3% of setting (5 A nominal phase current inputs, IA, IB, IC)
±0.01 A secondary and ±3% of setting (1 A nominal phase current inputs, IA, IB, IC)
Curve Timing: ±1.50 cycles and ±4% of curve time for currents between (and including) 2 and
30 multiples of pickup
Courtesy of NationalSwitchgear.com
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