GE L90 Instruction Manual page 603

CHAPTER 5: SETTINGS
This scheme uses an under-reaching zone 1 distance element to key a transfer trip signal(s) to the remote terminal(s)
where it is supervised by an over-reaching zone 2 distance element. For proper operation, the zone 1 and 2 phase and
ground distance elements must be enabled, configured, and set per rules of distance relaying.
In single-pole tripping applications, the scheme uses local fault type identification provided by the phase selector together
with information received from the remote terminal(s). The scheme generates output operands
that are used to transmit the signal to the remote end(s). Choices of communications channel include remote inputs/
outputs and telecommunications interfaces. When used with telecommunications facilities, assign the output operands to
operate output contacts connected to assert the individual bits at the interface.
To make the scheme a fully operational stand-alone feature, the scheme output operands must be configured to interface
with other relay functions, output contacts in particular. Typically, you program the output operands to initiate a trip,
breaker fail, and autoreclose, and drive a user-programmable LED as per user application. When used in conjunction with
the Trip Output element, the scheme is pre-configured to initiate trip, breaker fail and single-pole autoreclose actions.
— This setting allows the user to assign any FlexLogic operand to block the scheme. Contact inputs
PUTT SCHEME BLOCK
from a pilot cut-out switch are typically used for this purpose.
— This setting enables the relay to cope with spurious receive signals. Set this delay longer than the
PUTT RX PICKUP DELAY
longest spurious TX signal that can be received simultaneously with the zone 1 pickup. The selected delay increases the
response time of the scheme.
— The output FlexLogic operand
PUTT SEAL-IN DELAY
time delay is applied to this operand for coping with noisy communication channels such as a power line carrier. The
is a minimum guaranteed duration of the
SEAL-IN DELAY
scheme, the trip operands
PUTT TRIP
— This setting specifies the number of bits of the communications channel available for the
PUTT NO OF COMM BITS
scheme. The transmit codes and trip table of the PUTT scheme are identical as those for the direct under-reaching transfer
trip scheme.
through — These settings allow the user to select the FlexLogic operands that represent the receive
PUTT RX1 PUTT RX4
signals for the scheme. Typically input contacts interfacing with a signaling system are used. In single-bit applications,
must be used. In two-bit applications,
PUTT RX1
, , and
PUTT RX2 PUTT RX3 PUTT RX4
remote terminals through OR gates in the FlexLogic, and configure the resulting signals as the
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
PUTT RX3:

Off
PUTT RX4:

Off
PUTT SCHEME TARGET:

Self-Reset
PUTT SCHEME EVENT:

Disabled
(PUTT OP) is produced according to the PUTT scheme logic. A seal-in
PUTT OP
A, B, C, and are sealed-in for the same period of time.
3P
and
PUTT RX1 PUTT RX2
must be used. In multi-terminal applications, connect the
Range: FlexLogic operand
Range: FlexLogic operand
Range: Self-Reset, Latched, Disabled
Range: Disabled, Enabled
pulse. As this operand activates the trip table of the PUTT
must be used. In four-bit applications,
RX
CONTROL ELEMENTS
(PUTT TX1 through
PUTT TX4)
PUTT
,
PUTT RX1
signals from two or more
inputs.
PUTT RX
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