ABB REG670 - Filter Calculation Example

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
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
IEC13000178-2-en.vsd
A
B
C
IEC13000178 V3 EN
Figure 284: Example of filter calculation
Section 12 1MRK502052-UEN B
System protection and control
600
Technical manual