I.8
SEL-751 Relay Instruction Manual Date Code 20170927
Synchrophasors
Serial Port Settings for IEEE C37.118 Synchrophasors
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-751 automatically sets the TREA1–TREA4 or PMTRIG Relay
Word bits based on their default SEL
OGIC control equation. You must program
these bits to change their operation.
You can use these bits to send various messages at a low bandwidth via the
synchrophasor message stream. You can also use Digital Status Words to send
binary information directly, without the need to manage the coding of the
trigger reason messages in SEL
OGIC control equations.
Use these Trigger Reason bits if your synchrophasor system design requires
these bits. The SEL-751 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 can adjust the synchrophasor time stamp
accordingly.
NOTE: Set IRIGC = C37.118 only when
an IRIG-B000 signal is connected to
the relay. Set IRIGC = NONE when an
IRIG-B002 (standard IRIG) signal is
connected.
➤ IRIGC := NONE— ignores bit extensions
➤ IRIGC := C37.118— extracts bit extensions and corrects
synchrophasor time accordingly
Serial Port Settings for IEEE C37.118 Synchrophasors
IEEE C37.118 compliant synchrophasors are available via serial or Ethernet
port. The associated serial port settings are shown in Tab le I.5.
The serial port settings for PROTO := PMU, shown in Table I.5, do not
include the settings BITS and PARITY; these two settings are internally fixed
as BITS := 8, PARITY := N.
Serial port setting PROTO cannot be set to PMU (see Table I.5) when Global
setting EPMU := N. Synchrophasors must be enabled (EPMU := Y) before
PROTO can be set to PMU.
If you use a computer terminal session or
ACSELERATOR QuickSet SEL-5030
Software connected to a serial port, and then set that same serial port PROTO
setting to PMU, you lose the ability to communicate with the relay through
ASCII commands. If this happens, either connect via another serial port (that
Ta b le I .5 S EL- 75 1 Serial Port Settings for Synchrophasors
Setting Description Default
PROTO Protocol (SEL, MOD, DNET, DNP,
EVMSG, PMU, MBA, MBB, MB8A,
MB8B, MBTA, MBTB)
a
a
Some of the other PROTO setting choices may not be available.
SEL
b
b
Set PROTO = PMU to enable C37.118 synchrophasor protocol on this port.
SPEED Data Speed (300 to 38400) 9600
STOPBIT Stop Bits (1, 2) 1
RTSCTS HDWR HANDSHAKING (Y, N) N
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