P.3.240
SEL-411L Relay Protection Manual Date Code 20151029
Protection Functions
Trip Logic
TPC1, TPC2, and 3PT assert. Use these timers for the designated trip control
outputs. The trip output occurs for the TDURD time or the duration of the trip
condition, whichever is greater.
TDUR1D is the minimum trip duration time following a single-pole trip.
TDUR3D is the minimum trip duration time following a three-pole trip. If
another trip occurs during the single-pole open dead time following a single-
pole trip, TDUR3D replaces TDUR1D.
Trip During Open-Pole Time Delay
If another fault occurs, it is common to trip the two remaining phases for the
following two periods.
➤ During the single-pole-open interval following the original
single-pole trip.
➤ During the reclosing relay reclaim (reset) time state following
a single-pole reclose.
Use the reclosing function in the relay to reclose the breaker(s), see Internal
Recloser on page P.4.9. This section describes the E3PT, E3PT1, and E3PT2
settings necessary for autoreclose logic control of the single-pole and three-
pole tripping sequence. The TOPD (trip during open-pole time delay) setting
has no relevance in this situation.
If an external reclosing relay is being used, control signals from the reclosing
relay will typically be used to control the relay single- and three-pole tripping
sequence. Another method is to use the TOP (trip during open-pole) Relay
Word bit to select a three-pole trip after a single-pole trip in the relay by
making an appropriate setting for TOPD (trip during open-pole time delay),
and then including the TOP Relay Word bit in the E3PT setting—see
Figure 3.160. See External Recloser on page P.4.9 for additional information.
Timer setting TOPD (trip during open-pole time delay) determines the period
during which any subsequent single-pole trips are converted to a three-pole
trip following the original single-pole trip. To use this feature, include the
Relay Word bit TOP in the E3PT setting.
Trip Output Signals
There are seven Relay Word bits (TPA1, TPA2, TPB1, TPB2, TPC1, TPC2,
and 3PT) that you can program to drive contact outputs to trip circuit breakers.
Relay Word bits TPAn, TPBn, and TPCn are phase-selective tripping signals
for controlling the individual poles of the circuit breakers for single-pole
tripping schemes. Use Relay Word bit 3PT (three-pole trip) to trip all three
poles of both circuit breakers.
Manual Trip Logic
The relay also has additional logic for manually tripping the circuit breakers.
Use SEL
OGIC control equations BK1MTR and BK2MTR to trip the circuit
breakers manually. Use SEL
OGIC control equations ULMTR1 and ULMTR2
to unlatch manual trips for Circuit Breaker 1 and Circuit Breaker 2,
respectively.
Trip Logic Settings
and Relay Word Bits
The trip logic settings are shown in Table 3.125, and the Relay Word bits are
shown in Table 3.126. Some of the settings are only required in certain
situations, as noted.
To Next Page
Loading...
