Schweitzer Engineering SEL-351P, Quick Start Manual

Page: 192 / 674

3-24 Overcurrent, Voltage, Synchronism Check, and Frequency Elements Date Code 990430
SEL-351P Manual Técnico
Settings Ranges
Table SECTION 3: .4: Neutral Ground Time-Overcurrent Elements Settings
Setting Definition Range
51N1P
51N2P
pickup 0.005 - 0.160 A secondary (0.05 A nominal
channel IN current input)
51N1C
51N2C
curve type U1 - U5 (US curves), C1 - C5 (IEC curves),
recloser or user curves
see Figure 9.1 - Figure 9.20
51N1TD
51N2TD
time dial (has no multiplying
effect on constant time adder
or minimum response time) 0.50 - 15.00 (US curves), 0.05 - 1.00 (IEC
curves), 0.10 - 2.00 (recloser or user curves)
see Figure 9.1 - Figure 9.20
51N1RS
51N2RS
electromechanical reset
timing Y, N
51N1CT
51N2CT
constant time adder – adds
additional time to curve 0.00 - 60.00 cycles
(no effect if set = 0.00)
51N1MR
51N2MR
minimum response time –
flattens curve at set time;
curve can operate no faster
than this set time 0.00 - 60.00 cycles
(no effect if set = 0.00)
51N1TC
51N2TC
SEL
OGIC
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 SEL
OGIC
Control Equation torque control setting 51N1TC is set directly to logical 0
(i.e., 51N1TC = 0), then corresponding neutral ground time-overcurrent element 51N1T
is defeated and nonoperational, regardless of any other setting. 51N2T is similar.
See Section 9: Setting the SEL-351P Recloser Control for additional time-overcurrent element
setting information.
Accuracy
Pickup:
±
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
Residual Ground Time-Overcurrent Elements
To understand the operation of Figure SECTION 3: .16 and Figure SECTION 3: .17, follow the
explanation given for Figure SECTION 3: .14 in the preceding
Phase Time-Overcurrent