H.9
Date Code 20100129 Instruction Manual SEL-751A Relay
Synchrophasors
View Synchrophasors Using the MET PM Command
The Time Synchronization Relay Word bits in Table H.7 indicate the present
status of the timekeeping function of the SEL-751A.
View Synchrophasors Using the MET PM Command
The MET PM serial port ASCII command may be used to view the
SEL-751A synchrophasor measurements. See MET Command (Metering
Data) on page 7.32 for general information on the MET command.
There are multiple ways to use the MET PM command:
➤ As a test tool, to verify connections, phase rotation, and scaling
➤ As an analytical tool, to capture synchrophasor data at an exact
time, in order to compare it with similar data captured in other
phasor measurement unit(s) at the same time
➤ As a method of periodically gathering synchrophasor data
through a communications processor
The MET PM command displays the same set of analog synchrophasor
information, regardless of the Global settings PHDATAV, PHDATAI, and
PHCURR. The MET PM command can function even when no serial ports
are sending synchrophasor data—it is unaffected by serial port setting
PROTO.
The MET PM command will only operate when the SEL-751A is in the IRIG
timekeeping mode, as indicated by Relay Word bit TSOK = logical 1.
Figure H.4 shows a sample MET PM command response. The synchrophasor
data is also available via the HMI > Meter PM menu in
ACSELERATOR
QuickSet, and has a similar format to Figure H.4.
NOTE: In order to have the MET PM
xx:yy:zz response transmitted from a
serial port, the corresponding port
must have the AUTO setting set to
YES (Y).
The MET PM time command can be used to direct the SEL-751A to display
the synchrophasor for an exact specified time, in 24-hour format. For example,
entering the command MET PM 14:14:12 will result in a response similar to
Figure H.4 occurring just after 14:14:12, with the time stamp 14:14:12.000.
See Section 7: Communications for complete command options, and error
messages.
TREA2 Trigger Reason Bit 2 (SELOGIC)
TREA1 Trigger Reason Bit 1 (SEL
OGIC)
Table H.7 Time Synchronization Relay Word Bits
Name Description
IRIGOK Asserts while relay time is based on IRIG-B time source.
TSOK Time Synchronization OK. Asserts while time is based on an IRIG-B
time source of sufficient accuracy for synchrophasor measurement.
PMDOK Phasor Measurement Data OK. Asserts when the SEL-751A is enabled
and synchrophasors are enabled (Global setting EPMU := Y).
Table H.6 Synchrophasor Trigger Relay Word Bits (Sheet 2 of 2)
Name Description
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