ABB RELION REX640 Technical Manual page 1052

Section 4
Protection functions
1046
2
I RESO A _ _ I
= −
RMS A _
GUID-E1315338-40A6-452C-822E-574A61EB734B V1 EN
I
RMS value of current in phase A (contains up to 11
RMS_A
I DC-component in phase A current
DC_A
Fundamental component in phase A current
I_A
I
th
K harmonic component in phase A current, K is defined by setting
K_A
Num
Calculated resonance current for phase A
I_RESO_A
The resonance current is calculated through the filter implementation. The DC and
fundamental components are removed by passing the total RMS current through the
th
High pass filter. The K
filter output through the K
High pass filter and all the harmonic Band stop filters are shown in
GUID-BD5BB768-B7B6-415A-A559-DDB7CB66F22C V1 EN
Figure 564: Magnitude response of High pass and all the harmonic Band stop
filters
Similarly resonance current is calculated in the same way for phase B and phase C.
Resonance currents I_RESO_A, I_RESO_B and I_RESO_C are available in the
monitored data view.
The maximum of the three calculated resonance currents is further considered for
calculation.
I RESONANCE Max I RESO A I RESO B I RESO C
_
=
GUID-EF8BE785-FC1F-47EB-8EEF-52B9C7A41158 V1 EN
2 2 2
I I I
− −
1 _ A DC A _ K _ A
harmonic component is removed by passing the High pass
th
harmonic Band stop filter. The magnitude response of the
,
( _ _ _
1MRS759142 C
th
harmonic)
Tuning harmonic
Figure
, )
_ _ _
Technical Manual
(Equation 244)
564.
(Equation 245)
REX640