18.32
SEL-400 Series Relays Instruction Manual Date Code 20171006
Synchrophasors
SEL Fast Message Synchrophasor Protocol
➤ A serial port set with SPEED := 9600 can handle a single-
synchrophasor message at any data rate, a four-synchrophasor
message at as fast as 10 messages per second, and any size message
at as fast as 5 messages per second.
➤ A serial port set with SPEED := 300 cannot be used for Fast Message
synchrophasors.
Protocol Operation
The relay will only transmit synchrophasor messages over serial ports that have
setting PROTO := PMU. The connected device will typically be a synchrophasor
processor. The synchrophasor processor controls the PMU functions of the relay,
with SEL Fast Message commands, including commands to start and stop syn-
chrophasor data transmission, and commands to request a configuration block
from the relay, so the synchrophasor processor determine the correct configura-
tion for storing the synchrophasor data.
Transmit Mode Control
The relay will not begin transmitting synchrophasors until an enable message is
received from the synchrophasor processor. The relay will stop synchrophasor
transmission on a particular serial port when the disable command is received
from the synchrophasor processor, or when the relay settings for that port are
changed. The relay will stop synchrophasor transmission on all serial ports when
any Global or Group settings change is made.
The relay will respond to configuration block request messages regardless of the
present transmit status, waiting only as long as it takes for any partially-sent mes-
sages to be completely transmitted.
The relay will respond to a ping request immediately upon receipt, terminating
any partially sent messages.
Independent Ports
Each serial port with the PROTO := PMU setting is independently configured
and enabled for synchrophasor and Fast Operate commands. For example, if
there are two serial ports set to PROTO := PMU, the status of one port has no
effect on the other port. One port might be commanded to start transmitting syn-
chrophasor messages, while the other port is idle, responding to a configuration
block or Fast Operate request, or transmitting synchrophasors. The ports are not
required to have the same SPEED setting, although the SPEED setting on each
PROTO := PMU port will affect the minimum synchrophasor message data
period that can be used on that port.
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