Schweitzer Engineering SEL-2032 - Table 9.1 SEL-2032 Serial Port Bandwidth for Synchrophasors (in Bytes)

9.5
Date Code 20120126 Instruction Manual SEL-2032 Communications Processor
Protocols
SEL Fast Message Protocol
dedicated synchrophasor processor can collect synchrophasor data from
various Phasor Measurement Units (PMUs). The SEL-2032 uses SEL Fast
Message Unsolicited Write (UW) messages to collect synchrophasor data
from SEL devices such as the SEL-311 series relays, most of the SEL-351
series relays, the SEL-421 and SEL-451, and metering devices such as the
SEL-734.
Unsolicited Write (Synchrophasor) Messages
SEL Fast Message UW messages are general Fast Messages that transport
measured synchrophasor information. The rate that an SEL IED can send UW
messages to an attached SEL-2032 depends on the length of message data and
port BAUD setting. The SEL-421-2, for example, can send either positive-
sequence voltage (single synchrophasor), three-phase and positive-sequence
voltages (four synchrophasors), or three phases of voltage and current along
with positive-sequence voltage and current (eight synchrophasors maximum).
Message packet size starts at 40 bytes for the single-synchrophasor message
and increases to 64 and 96 bytes for the four- and eight-synchrophasor
options, respectively. Table 9.1 lists the supported SEL-2032 UW message
periods, available port BAUD settings, and the maximum message size that
can fit within the port bandwidth. Blank entries indicate bandwidths of less
than 40 bytes.
The formula used to calculate message size nn is:
nn = bps/(1.15 • L • f)
where:
Table 9.1 SEL-2032 Serial Port Bandwidth for Synchrophasors (in Bytes)
Requested
Message
Period
Equivalent Message Rate
Port Setting BAUD
(ms)
Msg per
second
Msg per
minute
300 600 1200 2400 4800 9600 19200
1000 1.0000 60 43 86 173 347 695 1391
2000 0.5000 30 43 86 173 347 695 1391 2782
3000 0.3333 20 65 130 260 521 1043 2086 4173
4000 0.2500 15 86 173 347 695 1391 2782 5565
5000 0.2000 12 108 217 434 869 1739 3478 6956
6000 0.1667 10 130 260 521 1043 2086 4173 8347
10000 0.1000 6 217 434 869 1739 3478 6956 13913
15000 0.0667 4 326 652 1304 2608 5217 10434 20869
20000 0.0500 3 434 869 1739 3478 6956 13913 27826
30000 0.0333 2 652 1304 2608 5217 10434 20869 41739
60000 0.0167 1 1304 2608 5217 10434 20869 41739 83478
bps = port BAUD
L = length of message byte (1 start bit, 8 data bits, 2 stop bits, 1 parity = 12)
f = frequency of messages in seconds
1.15 = factor to account for system delays
Courtesy of NationalSwitchgear.com