ABB RELION 620 Series Technical Manual page 803

1MRS757644 F
620 series
Technical Manual
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Figure 407: 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-DBF6D7C6-0BD4-4302-9A59-E57909928AB2 V1 EN
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 Tuning harmonic Num should
be set to 1 because the capacitor branch is not tuned for a special
frequency as in tuned filter applications. Even though Tuning
harmonic Num is set to 1, the fundamental component is subtracted
only once from I
Level detector 1
The maximum calculated resonance current is compared to the set Alarm start 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 Start value. If the
calculated I_RESONANCE exceeds the set Start value, this module sends the enabling
signal to the Timer 2 module.
( _ _ , _
.
RMS
Section 4
Protection functions
_ , _ _ )
(Equation 149)
797