Schweitzer Engineering SEL-351P, Quick Start Manual

Page: 175 / 674

Date Code 990430 Overcurrent, Voltage, Synchronism Check, and Frequency Elements 3-7
SEL-351P Manual Técnico
relays). These times do not include output contact operating time and, thus, are accurate for
determining element operation time for use in internal SEL
OGIC
Control Equations. Output
contact pickup/dropout time is 4 ms (0.25 cycle for a 60 Hz relay; 0.20 cycle for a 50 Hz relay).
If instantaneous overcurrent elements are made directional, the pickup time curve in
Figure SECTION 3: .5 is adjusted as follows:
multiples of pickup setting
≤
4: add 0.25 cycle
multiples of pickup setting > 4: add 0.50 cycle
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.2 2 3 4 5 6 7 8 9 10
Applied Current (Multiples of Pickup Setting)
Pickup T
ime (Cycles
)
Maximum
Minimum
Figure SECTION 3: .5: SEL-351P Recloser Control Nondirectional Instantaneous
Overcurrent Element Pickup Time Curve
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.2 2 3 4 5 6 7 8 9 10
Applied Current (Multiples of Pickup Setting)
R
es
et Time
(C
yc
le
s)
Maximum
Minimum
Figure SECTION 3: .6: SEL-351P Recloser Control Nondirectional Instantaneous
Overcurrent Element Reset Time Curve
Phase-to-Phase Instantaneous Overcurrent Elements
Four levels of phase-to-phase instantaneous overcurrent elements are available. The different
levels are enabled with the E50P enable setting, as shown in Figure SECTION 3: .7.