GE D90 Plus - Page 305

CHAPTER 7: PROTECTION CONTROL ELEMENTS
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL 295
The following settings are available.
Function
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the permissive under-reaching transfer trip (PUTT)
scheme.
RX Pickup Delay
Range: 0.000 to 65.535 seconds in steps of 0.001
Default: 0.000 seconds
This setting enables the relay to cope with spurious receive signals. Set this delay value
to be longer than the longest spurious TX signal that can be received simultaneously
with the zone 1 pickup. The selected delay increases the response time of the scheme.
Seal-In Delay
Range: 0.000 to 65.535 seconds in steps of 0.001
Default: 0.010 seconds
The PUTT OP FlexLogic operand is produced according to the scheme logic. A seal-in time
delay is applied to this operand for coping with noisy communication channels, such as
a power line carrier. This setting specifies a minimum guaranteed duration of the PUTT OP
pulse. As this operand activates the trip table of the PUTT scheme, the PUTT TRIP A, PUTT
TRIP B, PUTT TRIP C, and PUTT TRIP 3P trip operands are sealed-in for the same period of
time.
Communication Bits
Range: 1, 2, 4
Default: 1
This setting specifies the number of bits of the communications channel available for the
scheme. With only one bit available, the scheme sends the permissive under-reaching
transfer trip command on bit 1 (the PUTT TX1 operand) and responds to the direct trip
command received on bit 1 (the
RX1 setting). The scheme uses only local fault type
identification provided by the phase selector to assert the trip operands (PUTT TRIP A, PUTT
TRIP B, PUTT TRIP C, and PUTT TRIP 3P).
RX1 through RX4
Range: any FlexLogic operand
Default: OFF
These settings select the FlexLogic operands to represent the receive signals for the
scheme. Input contacts interfacing with a signaling system typically are used. These
settings are used in the following manner:
– In single-bit applications,
RX1 must be used
– In two-bit applications,
RX1 and RX2 must be used
– In four-bit applications,
RX1 through RX4 must be used
In multi-terminal applications, the RX signals from two or more remote terminals need to
be connected through OR gates in the FlexLogic and the resulting signals configured as
RX inputs.
Events
Range: Enabled, Disabled
Default: Enabled
This setting enables and disables the logging of permissive under-reaching transfer trip
(PUTT) scheme events in the sequence of events recorder.
The figure shows the PUTT scheme logic.