R.7.29
Date Code 20111215 Reference Manual SEL-421 Relay
Synchrophasors
C37.118 Synchrophasor Protocol
➤ The breaker 2 cts and wiring have a phase error of 5.50 degrees
(lagging) at 60 Hz.
➤ The synchrophasor data will be using port 3, and the maximum
baud allowed is 19200.
➤ The system designer specified floating point numeric
representation for the synchrophasor data, and rectangular
coordinates.
➤ The system designer specified integer numeric representation
for the frequency data.
➤ The system designer specified fast synchrophasor response,
because the data is being used for system monitoring.
The protection settings and RTD serial port settings will not be shown.
Determining Settings
The protection engineer performs a bandwidth check, using Ta ble 7.15 , and
determines the required message size. The system requirements, in order of
appearance in Tab le 7.15, are:
➤ 5 Synchrophasors, in floating point representation
➤ Integer representation for the frequency data
➤ 2 analog values
➤ 3 digital status bits, which require one status word
The message size is 16 + 5 • 8 + 2 • 2 + 2 • 4 + 1 • 2 = 70 bytes. Using
Tab le 7.16, the engineer verifies that the port baud of 19200 is adequate for the
message, at 10 messages per second.
Protection Math Variables PMV64 and PMV63 will be used to transmit the
RTD01 ambient temperature data and the station battery voltage DC1,
respectively.
The Protection SEL
OGIC Variables PSV64, PSV63, and PSV62 will be used to
transmit the breaker status, loss-of-potential alarm, and frequency
measurement status, respectively.
The Port 3 FASTOP setting will be set to N, to disable any control attempts
from the PMU port.
Make the Global settings as shown in Table 7.17.
Table 7.17 Example Synchrophasor Global Settings (Sheet 1 of 2)
Setting Description Value
NFREQ Nominal System Frequency (50, 60 Hz) 60
NUMBK Number of Breakers in Scheme (1, 2) 2
EPMU Enable Synchronized Phasor Measurement (Y, N) Y
MFRMT Message Format (C37.118, FM) C37.118
MRATE Messages per Second (1, 2, 4, 5, 10, 12, 15, 20, 30, 60) 10
PMAPP PMU Application (F = Fast Response, N = Narrow
Bandwidth)
F
PHCOMP Frequency-Based Phasor Compensation (Y, N) Y
PMSTN Station Name (16 characters) SAMPLE1
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