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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
If the frequency value is equal to or within ±20 Hz and V1
n
MPM/PTR
n
(secondary)
is larger than 0.1 • VNOM
n
then:
If the frequency value exceeds ±20 Hz or the V1
n
MPM/PTR
n
(secondary) is
below 0.1 • VNOM
n
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
k 1
–
–
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
)
Summary of Contents for SEL-421-4
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