Schweitzer Engineering Laboratories SEL-421-4 - Settings for Synchrophasors

18.6
SEL-400 Series Relays Instruction Manual Date Code 20171006
Synchrophasors
Settings for Synchrophasors
The PMU then calculates rate-of-change of frequency, dƒdt from the averaged
frequencies deviations (Equation 18.4).
Equation 18.4
If the frequency value is equal to or within ±20 Hz and V1nMPM/PTRn (secondary)
is larger than 0.1 • VNOMn then:
If the frequency value exceeds ±20 Hz or the V1nMPM/PTRn (secondary) is
below 0.1 • VNOMn then:
The frequency and rate-of-change of frequency are available as analog quantities
as well as for the synchrophasor data frames. The data are updated at the nominal
power system frequency.
Settings for Synchrophasors
Each SEL-400 series relay supports a variety of current and voltage terminals.
See the product-specific instruction manuals to see which terminals are available
to synchrophasors. Synchrophasors are primarily configured through the Global
settings. There are also a few port settings necessary to enable synchrophasor
communications.
Global Settings
The Global enable setting EPMU must be set to Y before the remaining synchro-
phasor settings are available. The PMU is disabled when EPMU := N.
FREQPM
k
= favg
k
+ NFREQ <analog>
DFDTPM
k
= dfdt
k
<analog>
After six consecutive cycles
FROKPM
k
= 1 <digital>
FREQPM
k
= FREQPM
k-1
<analog>
DFDTPM
k
= 0 <analog>
FROKPM
k
= 0 <digital>
Table 18.1 Synchrophasor Analog Quantities Frequency
Name Description Units
FREQPM Measured system frequency Hz
DFDTPM Rate-of-change of frequency Hz/s
dfdt
k
favg
k
favg
k1–
–
t
---------------------------------------------=
Table 18.2 Global Settings for Configuring the PMU (Sheet 1 of 2)
Setting Setting Prompt
EPMU Synchronized Phasor Measurement (Y, N)
MFRMT Message Format (C37.118, FM)
MRATE Messages per Second (1, 2, 4, 5, 10, 12, 15, 20, 30, 60)
a
PMAPP PMU Application (F, N, 1)
PMLEGCY Synchrophasor Legacy Settings (Y, N, N1
b
)