Schweitzer Engineering Laboratories SEL-311B, Instruction Manual

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3-20 Distance, Overcurrent, Voltage, Date Code 20011205
and Synchronism Check Elements
SEL-311B Instruction Manual
67P1TC = IN105 Input IN105 deasserted (67P1TC = IN105 = logical 0):
Phase instantaneous/definite-time overcurrent elements 67P1/67P1T are
defeated and nonoperational, regardless of any other setting.
Input IN105 asserted (67P1TC = IN105 = logical 1):
67P1/67P1T follows 50P1.
67P1TC = M2P The 67P1/67P1T uses the Zone 2 phase distance element to provide forward
directional control.
Other SEL
OGIC
control equation torque control settings may be set to provide directional control.
See Overcurrent Directional Control Provided by Torque Control Settings at the end of
Section 4: Loss-of-Potential, CCVT Transient Detection, Load-Encroachment, and
Directional Element Logic
.
Pickup and Reset Time Curves
Figure 3.14 and Figure 3.15 show pickup and reset time curves applicable to all nondirectional
instantaneous overcurrent elements in the SEL-311B Relay (60 Hz or 50 Hz 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 typically 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 (with standard directional elements
such as 32QF), the pickup time curve in Figure 3.14 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)
Pi
ckup T
ime (C
ycl
es)
Maximum
Minimum
Figure 3.14: SEL-311B Relay Nondirectional Instantaneous Overcurrent Element Pickup
Time Curve