Sel 751A, Instruction Manual

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H.8
SEL-751A Relay Instruction Manual Date Code 20100129
Synchrophasors
Synchrophasor Relay Word Bits
TREA1, TREA2, TREA3, TREA4, and PMTRIG
Defines the programmable trigger bits as allowed by IEEE C37.118.
Each of the four Trigger Reason settings, TREA1–TREA4, and the PMU
Trigger setting, PMTRIG, are SEL
OGIC
control equations in the Global
settings class. The SEL-751A evaluates these equations and places the results
in Relay Word bits with the same names: TREA1–TREA4, and PMTRIG.
The trigger reason equations represent the Trigger Reason bits in the STAT
field of the data packet. After the trigger reason bits are set to convey a
message, the PMTRIG Equation should be asserted for a reasonable amount
of time, to allow the synchrophasor processor to read the TREA1–TREA4
fields.
The SEL-751A automatically sets the TREA1–TREA4 or PMTRIG Relay
Word bits based on their default SEL
OGIC
equation. To change the operation
of these bits they must be programmed.
These bits may be used to send various messages at a low bandwidth via the
synchrophasor message stream. Digital Status Words may also be used to send
binary information directly, without the need to manage the coding of the
trigger reason messages in SEL
OGIC
.
Use these Trigger Reason bits if your synchrophasor system design requires
these bits. The SEL-751A synchrophasor processing and protocol
transmission are not affected by the status of these bits.
IRIGC
Defines if IEEE C37.118 control bit extensions are in use. Control bit
extensions contain information such as Leap Second, UTC time, Daylight
Savings Time, and Time Quality. When your satellite-synchronized clock
provides these extensions your relay will be able adjust the synchrophasor
time-stamp accordingly.
➤
IRIGC := NONE will ignore bit extensions
➤
IRIGC := C37.118 will extract bit extensions and correct
synchrophasor time accordingly
Synchrophasor Relay Word Bits
Table H.6 and Table H.7 list the SEL-751A Relay Word bits that are related to
synchrophasor measurement. The Synchrophasor Trigger Relay Word bits in
Table H.6 follow the state of the SEL
OGIC
control equations of the same
name, listed at the bottom of Table H.1 . These Relay Word bits are included in
the IEEE C37.118 synchrophasor data frame STAT field. See Table H.5 for
standard definitions for these settings.
NOTE:
The PM Trigger function is
not associated with the SEL-751A
Event Report Trigger ER, a SEL
OGIC
control equation in the Report
settings class.
Table H.6 Synchrophasor Trigger Relay Word Bits (Sheet 1 of 2)
Name Description
PMTRIG Trigger (SEL
OGIC
)
TREA4 Trigger Reason Bit 4 (SEL
OGIC
)
TREA3 Trigger Reason Bit 3 (SEL
OGIC
)