Reporting Filters - ABB RELION 670 SERIES Applications Manual

Section 6
Wide area measurement system
6.2.3.2
120
Name Type
FREQREFCHSEL INTEGER
FREQREFCHERR BOOLEAN
FREQTRIG BOOLEAN
DFDTTRIG BOOLEAN
MAGHIGHTRIG BOOLEAN
MAGLOWTRIG BOOLEAN

Reporting filters

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 15.
F
s
f
±
0
2
IECEQUATION2418 V1 EN
where,
f is the nominal frequency
0
F is the reporting rate
s
Values (Range) Unit
- -
0=Freq ref not -
available
1=Freq ref error
2=Freq ref
available
- -
- -
- -
- -
Line distance protection REL670 2.2 ANSI
1MRK 506 369-UUS -
Description
Frequency reference channel
number selected
Frequency reference channel
error
Frequency trigger
Rate of change of frequency
trigger
Magnitude high trigger
Magnitude low trigger
(Equation 15)
Application manual