ABB Relion 670 Series RES670, Technical Manual

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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
2 .
0
2
s
F
f
±
IECEQUATION2418 V1 EN
(Equation 2)
where,
f
0
is the nominal frequency
F
s
is the reporting rate
6.2.7.3 Scaling Factors for ANALOGREPORT channels
The internal calculation of analog values in RES670 is based on 32 bit floating point.
Therefore, if the user selects to report the analog data (
AnalogDataType ) as Integer , there
will be a down-conversion of a 32 bit floating value to a new 16 bit integer value. In such
a case, in order to optimize the resolution of the reported analog data, the user-defined
analog scaling is implemented in RES670.
The analog scaling in RES670 is automatically calculated by use of the user-defined
parameters
AnalogXRange for the respective analog channel X. The analog data value on
the input X will have a range between -AnalogXRange and +AnalogXRange . The
resulting scale factor will be applied to the reported analog data where applicable.
If the AnalogDataType is selected as Float , then these settings are ignored.
The analog scaling in RES670 is calculated using the equation:
2
65535.0
0.0
65535.0 16
AnalogXRange
S calefactor
offset
´
=
=
=
bit integer range
IECEQUATION2443 V1 EN
According to the IEEE C37.118.2 standard, the scale factors (conversion factor) for
analog channels are defined in configuration frame 2 (CFG-2) and configuration frame 3
(CFG-3) frames as follows:
1MRK 511 365-UUS A
Section 6
Wide area measurement system
Phasor measurement unit RES670 2.1 ANSI 141
Technical manual