ABB PQFA, Instruction Manual

Page: 43 / 98

PQFA Instructions Manual
Asea Brown Boveri Jumet S.A.
43
Figure 6.10. Back-up generator: CT connection (for one phase)
6.5. Precautions with capacitors
In the presence of power capacitors (LV or MV), harmonics below the
resonance frequency of the capacitor bank should not be handled by the filter
to avoid any risk of resonance. Those harmonics have to be deselected (see
chapter 10 on programming the filter).
Networks where the PQFA is installed have large harmonic content and it is
highly recommended that capacitor banks be fitted with detuning reactors.
The harmonics below the tuning frequency of the bank have also to be
deselected.
The following table indicates the harmonics to be deselected for main types of
detuned banks.
Detuned bank type Harmonics to
be deselected
5.67% 2, 3, 4.
6% 2, 3, 4.
7% 2, 3.
14% 2.
For other types of detuned bank or in the case of plain capacitors, please
contact your ABB Service provider to evaluate the resonance frequency and
the harmonics to be deselected.
S1, k
S2, l
S1, k
S2, l
P1
P2
P1
P2
S1
S2
k
L
PQF
G
P1, K
P2, L
P1, K
P2, L