Sel 411L - Table 3.111 Settings for the Time-Overcurrent Elements

P.3.212
SEL-411L Relay Protection Manual Date Code 20151029
Protection Functions
Selectable Time-Overcurrent Elements (51)
When IN202 asserts (IN201 deasserted), the 51P01 setting is:
(0 • 1.5) + (1 • 2) = 0 + 2 = 2
If, however, IN202 asserts while IN201 is still asserted, the 51P01
setting is:
(1 • 1.5) + (1 • 2) = 1.5 + 2 = 3.5
Because 3.5 exceeds the upper range value of 3.2, the relay clamps
the setting at 3.2 and asserts Relay Word bit 51MM01.
Torque Control
SELOGIC control equation 51TC01 allows you to state the conditions when
the element must run. When 51TC01 asserts (logical 1), switch S1 in
Figure 3.144 closes, and the relay evaluates input 51O01. For example, if the
element should only measure when the circuit breaker is closed, enter the
following:
51TC01 := IN201 (Breaker auxiliary “A” contact connected to IN201)
With this setting, switch S1 closes only when IN201 is a logical 1. If the
element must measure all the time, enter the following:
51TC01 := 1
To prevent the inadvertent omission of the inverse-time overcurrent protection,
the relay does not permit a torque-control SEL
OGIC control equation (51TCxx)
setting of 0 or NA.
EM Reset
Setting 51RS01 defines whether the curve resets like an electromechanical
disk or after one power system cycle when current drops below pickup. If you
set 51RS01 = Y, then the relay resets according to the reset timer equations for
that particular curve (see Table 3.108 or Table 3.109). If you set 51RS01 = N,
then the relay resets after one power system cycle when current drops below
pickup.
All 20 time-overcurrent elements have the same setting format, as shown in
Table 3.111.
Table 3.111 Settings for the Time-Overcurrent Elements
Setting Setting Description Range Default Value
51Oxx
a
a
xx = 01–10.
Operating quantity See Table 3.110 LIMAXM
51Pxx Pickup SMV
b
b
Relay operating range: 5 A Relay = 0.5 to 16.0 A secondary, 1 A Relay = 0.1 to 3.2 A secondary.
1.00
51Cxx Curve selection U1–U5 U1–U5, C1–C5 U1
51TDxx Time-dial (SEL math equation) SMV
c
c
U1 to U5 = 0.5 to 15, 1 A C1 to C5 = 0.05 to 1 A.
1.00
51RSxx EM reset Y or N N
51TCxx Torque control (SEL
OGIC equation) SELOGIC variable 1.00