ABB RELION RET670, Applications Manual

Page: 126 / 1016

Name Type Values (Range) Unit Description
FREQREFCHSEL INTEGER - - Frequency reference channel
number selected
FREQREFCHERR BOOLEAN 0=Freq ref not
available
1=Freq ref error
2=Freq ref
available
- Frequency reference channel
error
FREQTRIG BOOLEAN - - Frequency trigger
DFDTTRIG BOOLEAN - - Rate of change of frequency
trigger
MAGHIGHTRIG BOOLEAN - - Magnitude high trigger
MAGLOWTRIG BOOLEAN - - Magnitude low trigger
6.2.3.2 Reporting filters
GUID-D39153B5-81CE-4C1F-A816-C7A4C3407048 v2
The PMUREPORT function block implements the reporting filters designed to avoid
aliasing as the reporting frequency is lower than the sample/calculation frequency. This
means, the synchrophasor and frequency data which are included in the C37.118
synchrophasor streaming data are filtered in order to suppress aliasing effects, as the
rate of the C37.118 data is slower than the data rate for internal processing. For this
purpose, there is an anti-aliasing filter designed for each reporting rate. The correct
anti-aliasing filter will be automatically selected based on the reporting rate and the
performance class (P/M) settings. The filters are designed to attenuate all aliasing
frequencies to at least -40 dB (a gain of 0.01) at M class.
The synchrophasor measurement is adaptive as it follows the
fundamental frequency over a wide range despite the reporting rate.
For example, when the synchrophasor measurement follows the fundamental frequency
beyond the fixed Nyquist limits in C37.118 standard, the anti-aliasing filter stopband
moves with the measured fundamental frequency. This has to be considered in
connection with C37.118, where the passband is defined relative to a fixed nominal
frequency as shown in the equation
12 .
0
2
s
F
f
±
IECEQUATION2418 V1 EN-US
(Equation 12)
where,
f
0
is the nominal frequency
F
s
is the reporting rate
Section 6
1MRK 504 163-UUS A
Wide area measurement system
120 Transformer protection RET670 2.2 ANSI
Application manual