Capacitor Inrush Current Calculation
2
1 Capacitor Inrush Current Calculations This shows the derivation of the inrush calculations from IEEEC37.99. Energizing A Isolated Bank: I MAX = LS C V B LG * 2 (1) C B is the bank capacitance in microfarads LS is the system inductance in microhenries. As stated KVAR = 1000 10 2 6 2 - * * Π * C F V from (16) C B = ( F V KVAR Π * * 2 10 2 9 (2) Then Substitute C B from (20) with formula (21) we get I MAX = ( ( LS F V KVAR V G L Π * * * - 2 10 2 2 9 (3) Peak to Peak 9 10 . 31,622.8 I MAX = ( ( ( LS F V KVAR V L L G L Π * * * * - - 2 10 2 2 9 (4) ( F Π 2 ≈ 19.4163@60Hz 17.7245@50Hz
Transcript of Capacitor Inrush Current Calculation
1
Capacitor Inrush Current Calculations This shows the derivation of the inrush calculations from IEEEC37.99. Energizing A Isolated Bank:
IMAX =LSC
V BLG∗2 (1)
CB is the bank capacitance in microfarads LS is the system inductance in microhenries.
As stated KVAR =1000
102 62 −∗∗Π∗ CFVfrom (16)
ˆ CB = ( )FVKVAR
Π∗∗
210
2
9
(2)
Then Substitute CB from (20) with formula (21) we get
IMAX = ( )( )LS
FVKVAR
V GL
Π∗∗
∗ −
210
22
9
(3)
Peak to Peak
910 . 31,622.8
IMAX =
( )( )( )
LS
FVKVAR
V LLGL
Π∗∗
∗∗ −−
210
22
9
(4)
( )FΠ2 ≈ 19.4163@60Hz 17.7245@50Hz
2
Then
IMAX = LSV
KVARV GL
∗∗∗ −
2
4163.198.622,312
(5)
LET = ( )23∗−GLV
This will allow us to re-arrange (5) to the following
IMAX =LS
KVARV
V
GL
GL ∗∗∗
∗∗
−
−
4163.193
8.622,312 (6)
≅ ( ) ( )( )LS
KVAR∗∗ 673.162881649658.0 (7)
Giving us the following inrush formulas
LS
KVAR1330≅ For 60 Hz (8)
LS
KVAR7.1456≅ For 50 Hz (9)
Neal S. Ciurro Neal S. Ciurro 2/12/04
