CHAPTER 5: SETTINGS
CONTROL ELEMENTS
L60 LINE PHASE COMPARISON SYSTEM – INSTRUCTION MANUAL
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The trip output element works in association with other L60 elements that must be programmed and in-service for
successful operation. The necessary elements are: recloser, breaker control, open pole detector, and phase selector. The
recloser must also be in the “Reset” state before a single pole trip can be issued. Outputs from this element are also directly
connected as initiate signals to the breaker failure elements.
At least one internal protection element or digital input representing detection of a fault must be available as an input to
this element. In pilot-aided scheme applications, a timer can be used to delay the output decision until data from a remote
terminal is received from communications facilities, to prevent a three pole operation where a single pole operation is
permitted.
The following settings are available for the trip output element.
TRIP MODE
— This setting is used to select the required mode of operation. If selected to “3 Pole Only” outputs for all three
phases are always set simultaneously. If selected to “3 Pole & 1 Pole” outputs for all three phases are set simultaneously
unless the phase selector or a pilot aided scheme determines the fault is single-phase-to-ground. If the fault is identified as
being AG, BG, or CG only, the operands for the faulted phase are asserted.
TRIP 3-POLE INPUT1
to
TRIP 3-POLE INPUT6
— These settings are used to select an operand representing a fault condition
that is not wanted to initiate a single pole operation (for example, phase undervoltage). Use a FlexLogic OR-gate if more
than six inputs are required.
TRIP 1-POLE INPUT1
to
TRIP 1-POLE INPUT6
— These settings are used to select an operand representing a fault condition
that is wanted to initiate a single pole trip-and-reclose if the fault is single phase to ground (for example, distance zone 1).
Use a FlexLogic OR-gate if more than six inputs are required. The inputs do not have to be phase-specific as the phase
selector determines the fault type.
The
AR FORCE 3-P TRIP
operand is asserted by the autorecloser 1.5 cycles after single-pole reclosing is initiated. This operand
calls for a three-pole trip if any protection element configured under
TRIP 1-POLE INPUT
remains picked-up. The open pole
detector provides blocking inputs to distance elements, and therefore the latter resets immediately after the
TRIP 1-POLE
operand asserts. For other protection elements used in single-pole tripping, ensure that they reset immediately after
tripping, otherwise the fact that they are still picked up is detected as an evolving fault and the relay trips three-poles. For
example, if high-set phase instantaneous overcurrent is used (
TRIP 1-POLE INPUT X
: “PHASE IOC1 OP”), then
OPEN POLE OP
Φ
A
is used for blocking phase A of the instantaneous overcurrent element. In this way, after tripping phase A, the phase a
instantaneous overcurrent element is forced to reset. Phases B and C are still operational and can detect an evolving fault
as soon as 8 ms after tripping phase A. Neutral and negative-sequence instantaneous overcurrent elements are blocked
from the
OPEN POLE BLK N
operand unless the pickup setting is high enough to prevent pickup during single-pole reclosing.
TRIP RECLOSE INPUT1
to
TRIP RECLOSE INPUT6
— These settings select an operand representing a fault condition that is
wanted to initiate three pole reclosing (for example, phase distance zone 1). Use a FlexLogic OR-gate if more than six
inputs are required. These inputs also include the
TRIP 1-POLE INPUT1
to
TRIP 1-POLE INPUT6
values, which are intended to
initiate three-pole reclosing in situations where single-pole tripping commands are changed to three-pole tripping
commands. This can happen in cases where the phase selector identifies a multi-phase fault or the
AR FORCE 3P TRIP
command is present.
TRIP SEAL-IN DELAY
— This setting specifies the minimum time that trip command signals are maintained to provide
sufficient time to open the breaker poles. If a value of “0” is specified, then the output signal is reset once the protection
elements initiating the trip are reset. If a value other than “0” is specified, then the protection elements must reset and the
timer initiated at the first trip command must expire.
TRIP RESET
— This setting selects the option to reset the trip latches. If “Pole Curr OR Custom” is chosen, then program the
OPEN POLE CURRENT PKP
setting accordingly. If “CBaux OR Custom” is chosen, then set the breakers appropriately. Both the
“Current” and “CBaux” options can be complimented by custom conditions using the
BKR
Φ
A OPEN
,
BKR
Φ
B OPEN
, and
BKR
Φ
C OPEN
settings indicated below. Alternately, a purely custom condition can be applied to reset trip output latches.
To ensure correct operation of the single pole tripping feature, any non-distance protection used for single pole
tripping (such as high-set overcurrent using the instantaneous or directional overcurrent elements) must be
blocked by the
OPEN POLE OP
Φ
A
,
OPEN POLE OP
Φ
B
, or
OPEN POLE OP
Φ
C
operands. For example, instantaneous
overcurrent phase A is blocked by
OPEN POLE OP
Φ
A
operand. This blocking condition is pre-wired for distance
protection.