Capacitor Bank 5th Harmonic Bank 7th harmonic Bank
KVAR 2.564 MVAR 2.3235
Voltage 14.81 kV 14.94
X c at 50 Hz 85.54 KV2/MVA 96.06
C= 1/(2xΠxFxXc)
F= 50 50
Π= 3.14 3.142857143
C= 0.00003719 0.00003312
37.19 micro F 33.12 micro F
Reactor
Reactance value, L 12.876 mH 2.724 mH
At Tuning frequency XL=XC
XL= 2xΠxFxL
2ΠL= 0.0809348571 0.017122286
2ΠC= 0.000233796 0.000208196
F ²= 1/(2ΠL)( 2ΠC)
F ²= 52847.7492886888 280521.9071
F= 229.8863834347 Hz 529.6431885
Harmonic no= 4.5977276687 10.59286377
Voltage harmonics is considered to be 5%
rmonic Bank 5th harmonics 11th harmonics
tuning 4.73% tuning 0.89%
XL-XC I Irms
XL 4.046743 81.50 99.9545 100.92814465 XL 0.856114
XC 85.54 XC 96.06
XC5 17.1089 3.124814 13.68171 XC5 19.2127
XL5 20.23371 XL5 4.280571
XC7 12.22064 16.10656 2.654372 XC7 13.72336
XL7 28.3272 XL7 5.9928
XC11 7.776773 36.7374 1.16374 XC11 8.733048
XL11 44.51417 XL11 9.417257
90
Imp
80 I XC13 7.389502
81.5 XL13 11.12949
70
5th 3.1248 14
60
7th 16.1066 3 XC15 6.404235
50 36.73 1 Imp
11th XL15 12.84171
I
40 100
Column K
30 Column L 90 Imp I
20 80 95.21
10 5th70 14.93213 3
7th60 7.730561 6
0
5th 7th 11th 11th
50 0.684209 63
13th
40 3.739984 12
15th
30 6.437479 7
20
10
0
5th 7th 11th 13th 15th
11th harmonics
XL-XC I Irms
95.21 89.79072 89.8 109.8865
14.93213 2.888272 2.8882721
7.730561 5.578905 5.5789052
0.684209 63.03343 63.033427
3.739984 11.53162 11.531618
6.437479 6.699527 6.6995268
Imp
I
Column Q
Column R
7th 11th 13th 15th
Load on Rectifier
case1 Present Load
direct current 18 kA
Voltage 180 V
Power DC 3240 Kw
Rectifier AC to DC con 0.94
Input AC power 3446.8085 KW
Uncompensated power 0.82 assumed
Input KVA 4203.425 KVA
Primary Voltage 11 kV
Input current 220.6226
Harmonic current calculation assuming 6 pulse operation
PU current Value in A Effective current Worst case Selected rating
Fundamental 1 220.62
5th 0.192 42.36 42.36 42.36 99.95
7th 0.132 29.12
11th 0.073 16.11 45.23 87.59 89.8
13th 0.057 12.58
Conclusion: Total Harmonic current up to 11th is 87.59 A, both the banks are suitable for worst case of sucking all the ha
Case 2 Full load
direct current 22 kA
Voltage 200 V
Power DC 4400 Kw
Rectifier AC to DC con 0.94
Input AC power 4680.8511 KW
Uncompensated power 0.82 assumed
Input KVA 5708.355 KVA
Primary Voltage 11 kV
Input current 299.61093
Harmonic current calculation assuming 12 pulse operation
PU current Value in A Effective current Worst case Selected rating
Fundamental 1 299.61
5th 0.192 57.53 17.26 17.26 99.95
7th 0.132 39.55 11.86
11th 0.073 21.87 21.87 50.99 89.8
13th 0.057 17.08 17.08
Conclusion: Both the bank ratings are more than worst case of 50.99 A, hence adequate
Notes:
30 % of 5th and 7th Harmonic current is considered for the 12 pulse operation while computing effective current
Harmonic filter bank is expected to suck all harmonics numbers below it as worst case
Refer page no 82 of IEEE519 for pu values of harmonic currents
Basis for worst case
all harmonics up to 5th
all harmonics up to 11th
worst case of sucking all the harmonics uo to 11th
Basis Worst case KVAR of Bank
all harmonics up to 5th 2563.88466
all harmonics up to 11th 2323.74015
uting effective current
