3.23
Date Code 20080213 Instruction Manual SEL-351A Relay
Overcurrent, Voltage, Synchronism Check, and Frequency Elements
Time-Overcurrent Elements
Settings Ranges
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 channel IN current input)
±0.01 A secondary and ±3% of setting
(1 A nominal channel IN current input)
±5 mA secondary and ±3% of setting
(0.2 A nominal channel IN current input)
±1 mA secondary and ±5% of setting
(0.05 A nominal channel IN current input)
Curve Timing:
±1.50 cycles and ±4% of curve time for currents between (and including)
2 and 30 multiples of pickup
±3.50 cycles and ±4% of curve time for currents between (and including)
2 and 30 multiples of pickup for 0.05 A nominal channel IN current input
Residual-Ground
Time-Overcurrent
Element(s)
One or two residual-ground time-overcurrent elements are available. The
element(s) are enabled with the E51G enable setting as shown in Table 3.5.
Table 3.4 Neutral-Ground Time-Overcurrent Element Settings
Setting Definition Range
51NP pickup 0.500–16.000 A secondary
(5 A nominal channel IN current input)
0.100–3.200 A secondary
(1 A nominal channel IN current input)
0.005–0.640 A secondary
(0.2 A nominal channel IN current input)
0.005–0.160 A secondary
(0.05 A nominal channel IN current input)
51NC curve type U1–U5 (US curves) see Figure 9.1–Figure 9.10
C1–C5 (IEC curves)
51NTD time dial 0.50–15.00 (US curves) see Figure 9.1–Figure 9.10
0.05–1.00 (IEC curves)
51NRS electromechanical
reset timing
Y, N
51NTC SEL
OGIC control
equation torque
control setting
Relay Word bits referenced in Ta bl e 9. 5 or set directly
to logical 1 (= 1)
a
a
SELOGIC control equation torque control setting (e.g., 51NTC) cannot be set directly to
logical 0.
Courtesy of NationalSwitchgear.com
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