Schweitzer Engineering Laboratories SEL-311C - Additional Settings Examples

5.5
Date Code 20060320 Instruction Manual SEL-311C Relay
Trip and Target Logic
Trip Logic
Set Trip
In SELOGIC control equation setting TR = M1P + Z1G + M2PT + Z2GT +
51GT + 51QT + OC:
➤ Distance elements M1P, M2PT, Z1G, and Z2GT and time-
overcurrent elements 51GT and 51QT trip directly. Time-
overcurrent and definite-time overcurrent elements can be
torque controlled (e.g., elements 51GT and 51QT are torque
controlled by SEL
OGIC control equation settings 51GTC and
51QTC, respectively). Check torque control settings to see if
any control is applied to time-overcurrent and definite-time
overcurrent elements. Such control is not apparent by mere
inspection of trip setting TR or any other SEL
OGIC control
equation trip setting.
➤ Relay Word bit OC asserts for execution of the OPEN
Command. See OPE Command (Open Breaker) on page 10.36
for more information on the OPEN Command.
With setting TDURD = 9.000 cycles, once the TRIP Relay Word bit asserts
via SEL
OGIC control equation setting TR, it remains asserted at logical 1 for a
minimum of 9 cycles.
Unlatch Trip
In SELOGIC control equation setting ULTR =!(50L + 51G):
Both elements must be deasserted before the trip logic unlatches and the
TRIP Relay Word bit deasserts to logical 0.
Additional Settings
Examples
The factory setting for SELOGIC control equation setting ULTR is a trip
element unlatch condition. A circuit breaker status unlatch trip condition can
be programmed as shown in the following examples.
Unlatch Trip With 52a Circuit Breaker Auxiliary Contact
A 52a circuit breaker auxiliary contact is wired to optoisolated input IN101.
52A = IN101 (SELOGIC control equation circuit breaker status setting—see
Optoisolated Inputs on page 7.3)
ULTR = !52A
Input IN101 has to be de-energized (52a circuit breaker auxiliary contact has to
be open) before the trip logic unlatches and the TRIP Relay Word bit deasserts
to logical 0.
ULTR = !52A = NOT(52A)
Unlatch Trip With 52b Circuit Breaker Auxiliary Contact
A 52b circuit breaker auxiliary contact is wired to optoisolated input IN101.
52A = !IN101
(SELOGIC control equation circuit breaker status setting—see
Optoisolated Inputs)
ULTR = !52A