![ABB Relion RES670 Technical Manual Download Page 366](http://html.mh-extra.com/html/abb/relion-res670/relion-res670_technical-manual_4485366.webp)
If for any reason this natural frequency band shall be extended (e.g. to get accurate but
wider filter) it is possible to increase the pass band by entering the value different from
zero for parameter
FreqBandWidth
. In such case the total filter pass band can be
defined as:
FreqBandWidth
value)
Example if in 60Hz system the selected values are “
FilterLength
=1.0 s” and
“
FreqBandWidth
= 5.0” the total filter pass band will be ±(3.6+5.0/2)= ± 6.1 Hz.
It shall be noted that the phasor calculation is relatively computation demanding
(required certain amount of the CPU processing time). In order to control the CPU
usage for this filter, the setting parameter
OverLap
is used. This setting parameter
defines how often the new phasor value is calculated during time period defined by the
set value for the parameter
FilterLength
). The following list gives some
examples how this parameter influence the calculation rate for the extracted phasor:
•
when
OverLap
=0% the new phasor value is calculated only once per
FilterLength
•
when
OverLap
=50% the new phasor value is calculated two times per
FilterLength
•
when
OverLap
=75% the new phasor value is calculated four times per
FilterLength
•
when
OverLap
=90% the new phasor value is calculated ten times per
FilterLength
12.1.7
Filter calculation example
GUID-F5828B0A-CED3-483E-B5B1-F389C3C2AEFB v3
In the following Figure an example from an installation of this filter on a large, 50 Hz
turbo generator with a rating in excess of 1000 MVA is presented. In this installation
filter is used to measure the stator sub-synchronous resonance currents. For this
particular installation the following settings were used for the filter:
•
SetFrequency
= 31.0 Hz
•
FilterLength
= 1.0 s
•
OverLap
= 75%
•
FreqBandWidth
= 0.0 Hz
Section 12
1MRK 511 408-UUS A
System protection and control
360
Phasor measurement unit RES670 2.2 ANSI
Technical manual
Summary of Contents for Relion RES670
Page 1: ...RELION 670 SERIES Phasor measurement unit RES670 Version 2 2 ANSI Technical manual ...
Page 2: ......
Page 276: ...270 ...
Page 306: ...300 ...
Page 360: ...354 ...
Page 406: ...400 ...
Page 614: ...608 ...
Page 732: ...726 ...
Page 748: ...742 ...
Page 884: ...878 ...
Page 932: ...926 ...
Page 933: ...927 ...