Sel 411L - Table 3.124 Setting TULO Unlatch Trip Options

P.3.239
Date Code 20151029 Protection Manual SEL-411L Relay
Protection Functions
Trip Logic
DTA, DTB, and DTC
The DTA, DTB, and DTC SELOGIC control equations determine which
elements directly trip the remote terminal. Each equation is phase selective. If
you are applying three-pole tripping only, set DTA, DTB, and DTC to the
same Relay Word bit expression.
TRSOTF
The TRSOTF control equation defines which elements trip while SOTF
protection is active. These elements trip instantaneously if they assert during
the SOTFD time.
TRCOMM
The TRCOMM and TRCOMMD SELOGIC control equation determines
which elements trip via the communications-based scheme logic. You would
typically set the overreaching Zone 2 distance elements or Level 2 directional
overcurrent elements in the TRCOMM SEL
OGIC control equation. Normally,
you need only one equation, but if you want to separate distance and
directional elements, use both equations. For example, enter the distance
elements in the TRCOMM equation and the direction elements in the
TRCOMMD equation.
Trip Unlatch Options
Unlatch the trip contact output after the trip to remove dc voltage from the trip
coil. The relay provides two settings to unlatch trip contact outputs after a
protection trip has occurred.
➤ TULO—following a protection trip, phase selective
➤ ULTR—following a protection trip, all three poles
TULO
Table 3.124 shows the four trip unlatch options for setting TULO.
ULTR
Use ULTR, the unlatch trip SELOGIC control equation, to define the
conditions that unlatch the trip contact outputs. This method always unlatches
all three poles.
Timers
The relay provides dedicated timers (minimum trip duration, trip during open
pole, etc.) for the trip logic.
Minimum Trip Duration
The minimum trip duration timer settings, TDUR1D and TDUR3D, determine
the minimum length of time that Relay Word bits TPA1, TPA2, TPB1, TPB2,
Table 3.124 Setting TULO Unlatch Trip Options
Option Description
1 Unlatch the trip when the relay detects that one or more poles of the line
terminal are open and the Relay Word bit 3PT has deasserted.
2 Unlatch the trip when the relay detects that the corresponding 52A
contact(s) from both circuit breakers (e.g., 52AA1 and 52AA2) are deasserted.
3 Unlatch the trip when the relay detects that the conditions for Options 1 and 2
are satisfied.
4 Do not run this logic.