ABB RELION REX640 Technical Manual page 1144

Protection functions
response of the High pass filter and all the harmonic Band stop filters are shown in
Figure 640
Figure 640: 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 _
Level detector 1
The maximum calculated resonance current is compared to the set
value . If the calculated I_RESONANCE exceeds the set Alarm start value , the module
sends the enabling signal to the Timer 1 module.
Level detector 2
The maximum calculated resonance current is compared to the set
the calculated I_RESONANCE exceeds the set
enabling signal to the Timer 2 module.
1144
.
Max I RESO A I RESO B I RESO C ( _
=
If a capacitor bank is used only for reactive power compensation and
there is no series reactor in a filter branch, the resonance protection is
very important. In this case, the setting
set to 1 because the capacitor branch is not tuned for a special frequency
as in tuned filter applications. Even though
to 1, the fundamental component is subtracted only once from I
_ , _ _ , _
Tuning harmonic Num should be
Tuning harmonic Num is set
Start value , this module sends the
1MRS759142 F
_ )
(Equation 290)
.
RMS
Alarm start
Start value . If
REX640
Technical Manual