ABB LIMITED
SHORT CIRCUIT FORCE FOR EQUIPMENT
INTERCONNECTION
Sheet 1 of 17
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SHORT CIRCUIT FORCE FOR
EQUIPMENT INTERCONNECTION
OWNER
M/S SHREE CEMENT LTD.
OWNER’S ENGINEER
Evonik Energy Services (I) Pvt. Ltd.,
Noida
EPC CONTRACTOR
Cethar Vessels Limited,
Tiruchirapalli
eBOP CONTRACTOR
ABB Limited, Faridabad
R0
21.04.2010
RK/RM
Rev
No.
Date
Prepared
by
Reviewed
by
Approved
by
Remarks
ABB LIMITED
SHORT CIRCUIT FORCE FOR EQUIPMENT
INTERCONNECTION
Sheet 2 of 17
REVISION STATUS SHEET
REV. NO.
DATE
DESCRIPTION
R0
21.04.2010
FOR APPROVAL
I System Data:
1.1 Nominal System voltage in kV
=
400
1.2 System short circuit current in A
(I"k3) =
40000
1.3 Factor for peak short circuit current
(κ) =
1.81
1.4 Phase spacing in m
(a m) =
7
1.5 System frequency in Hz
(f)
=
50
1.6 Auto Reclosing Feature
YES
II Conductor data:
2 1 Busbar selected
=
4" IPS (Schedule 80) Al
Short Circuit Force Calculation
(For Equipments)
2.1 Busbar selected
2.2 Outer diameter
(Do)
=
114.3
mm
2.3 Inner Diameter
(Di)
=
97.18
mm
2.4 Area of Cross section
(A)
=
2844
sq.mm
2.5 Moment of inertia
(J)
=
4.00E-06
m^4
2.6 Weight
(m')
=
7.678
kg/m
2.7 Young's Modulus
(E)
=
6.57E+10 N/ sq.m
III Reference
3.1 IEC 865 -1(1993): short circuit current calculation effects
4 IPS (Schedule 80) Al
IV
Legend:
Symbol
Unit
4.1 Initial symmetrical short circuit current (r.m.s)
I"k3
Amps
4.2 Peak short circuit current
Ip3
Amps
4.3 Effective distance between main conductors
am
m
4.4 Span between supports
l
m
4.5 Outer Diameter of the conductor
Do
m
4.6 Absolute permeability of vacuum
µo
4.7 Ratio of dynamic and static force on support (As per
equation in page no. 107 of IEC 865 -1(1993))
V
F4.8 Ratio of stress for a main conductor with or with out three
phase auto reclosing (As per equation in page no. 109 of
IEC 865 -1(1993))
V
r4.9 Factor for force on support (from table 3 of pg. 67 of IEC
865-1(1993))
a
4.10 Factor for relevant natural frequency estimation (From
table 3 of pg. 67 of IEC 865-1, 1993)
γ
4.11 Natural frequency of the tube
fc
Hz
4.12 Electromagnetic force
F m
kg
4.13 Total static weight of bus
M
kg
4.14 Reaction due to electrodynamic force
Fd
kg
4.15 Youngs Modulus of conductor
E
N/m²
V
Formulae Used
5.1 Peak value of short circuit current
(Ip3)
= I"k3 x k
x Sqr(2)
Amps
5.2
Electro magnetic force between
conductors
(Fm)
= µ x Sqr(3) x ( Ip3) ² x
l
kg
2 x 2 p
x 9.81 x am
5.3 Electro dynamic force on busbar
(Fd)
= Vf x Vr x a x Fm
kg
5.4 Natural Frequency of the tube
(fc)
=
γ x Sqr ( E J /m') Hz
l ²
5.5 Calculation of V
FAs per IEC 865-I (Page-107)
fc/f
V
F<0.04
0.232+3.52*EXP(-1.45*k)+0.166*LOG10(fc/f)
0.04...0.8
MAX(0.839+3.52*EXP(-1.45*k)+0.6*LOG10(fc/f),2.38+6*LOG10(fc/f))
0.8...1.2
1.8
1.2...1.6
1.23+7.2*LOG10(fc/f)
1.6...2.4
2.7
2.4...2.74
8.59-15.5*LOG10(fc/f)
2.74...3.0
8.59-15.5*LOG10(fc/f)
3.0...6.0
1.5-0.646*LOG(fc/f)
>6
1
5.6 Calculation of V
rfc/f
V
r<=0.05
1.8
>0.05 and <1
1-0.615Log(fc/f)
>=1
1
VI Support Arrangement
Refer Figure 1
6.1 Equipment Dimension (Terminal to Terminal) in m 4.8 m
Left Right
6.2 Support Span in Metre (L) = 9 10.5 6.3 Equipment Dimension (Terminal to Terminal) in m 4.821 0 6.4 Support type for Equipment FIXED SIMPLE 6.5 Support type for other equipment SIMPLE FIXED
VII Calculation
7.1 Peak short circuit current Ip3 = 102389 A
Left Right 7.2 Factor a at Support A 0.625 0.375 7.3 Factor a at Support B 0.375 0.625 7.4 Factor b 0.73 0.73 7.5 Factor γ 2.45 2.45 7.6 Effective Distance (mts) l = 4.19 8.1 7.7 Electromagnetic forces between conductors Fm = 110.79 214.18 7.8 Natural frequency of the Tube (Hz) fc = 25.824 6.9099
7.9 Ratio fc / f = 0.5165 0.1382
7.10 Ratio of dynamic & Static force on supports VF = 1.0128 0.6692 7.11 Ratio of stress for main conductor with &
without 3 phase Auto reclosing VR = 1.1765 1.5286
7.12 Factor a 0.625 0.375
7.13 Dynamic force (Bending Force) (kg) Fd = 82.505 82.164 7.14 Total Dynamic force due to Left & Right spans = 164.67 kg
TYPICAL SHORT CIRCUIT FORCE CALCULATION FOR 400kV
ISOLATOR
VI Support Arrangement Refer Figure 2
6.1 Equipment Dimension (Terminal to Terminal) in m 4.821 m Left Right
6.2 Support Span in Metre (L) = 12 9
6.3 Equipment Dimension (Terminal to Terminal) in m 0.55 4.8
6.4 Support type for Equipment SIMPLE SIMPLE
6.5 Support type for other equipment FIXED FIXED
VII Calculation
7.1 Peak short circuit current Ip3 = 102389 A
Left Right 7.2 Factor a at Support A 0.375 0.375 7.3 Factor a at Support B 0.625 0.625 7.4 Factor b 0.73 0.73 7.5 Factor γ 2.45 2.45 7.6 Effective Distance (mts) l = 9.315 4.189
7.7 Electromagnetic forces between conductors Fm = 246.31 110.77 7.8 Natural frequency of the Tube (Hz) fc = 5.2249 25.836
7.9 Ratio fc / f = 0.1045 0.5167
7.10 Ratio of dynamic & Static force on supports VF= 0.5964 1.0129 7.11 Ratio of stress for main conductor with & without
3 phase Auto reclosing VR= 1.6032 1.1763
7.12 Factor a 0.375 0.375
7.13 Dynamic force (Bending Force) Fd = 88.317 49.492
7.14 Total Dynamic force due to Left & Right spans = 137.81 kg
TYPICAL SHORT CIRCUIT FORCE CALCULATION FOR 400kV
CIRCUIT BREAKER
VI Support Arrangement Refer Figure 3
6.1 Equipment Dimension (Terminal to Terminal) in m 0.55 m Left Right
6.2 Support Span in Metre (L) = 12 5.5
6.3 Equipment Dimension (Terminal to Terminal) in m 4.82 4.8
6.4 Support type for Equipment FIXED SIMPLE
6.5 Support type for other equipment SIMPLE FIXED
VII Calculation
7.1 Peak short circuit current Ip3 = 102389 A
Left Right 7.2 Factor a at Support A 0.625 0.375 7.3 Factor a at Support B 0.375 0.625 7.4 Factor b 0.73 0.73 7.5 Factor γ 2.45 2.45 7.6 Effective Distance (mts) l = 9.318 2.827
7.7 Electromagnetic forces between conductors Fm = 246.39 74.7526 7.8 Natural frequency of the Tube (Hz) fc = 5.2215 56.7273
7.9 Ratio fc / f = 0.1044 1.13455
7.10 Ratio of dynamic & Static force on supports VF= 0.5962 1.8 7.11 Ratio of stress for main conductor with & without
3 phase Auto reclosing VR= 1.6034 1
7.12 Factor a 0.625 0.375
7.13 Dynamic force (Bending Force) Fd = 147.22 50.458
7.14 Total Dynamic force due to Left & Right spans = 197.67 kg
TYPICAL SHORT CIRCUIT FORCE CALCULATION FOR 400kV
CURRENT TRANSFORMER
VI Support Arrangement Refer Figure 4
6.1 Equipment Dimension (Terminal to Terminal) in m 0 m Left Right
6.2 Support Span in Metre (L) = 10.5 0
6.3 Equipment Dimension (Terminal to Terminal) in m 4.8 0
6.4 Support type for Equipment FIXED
6.5 Support type for other equipment SIMPLE
VII Calculation
7.1 Peak short circuit current Ip3 = 102389 A
Left Right 7.2 Factor a at Support A 0.625 0 7.3 Factor a at Support B 0.375 0 7.4 Factor b 0.73 0 7.5 Factor γ 2.45 0 7.6 Effective Distance (mts) l = 8.1 0
7.7 Electromagnetic forces between conductors Fm = 214.18 0 7.8 Natural frequency of the Tube (Hz) fc = 6.9099 0
7.9 Ratio fc / f = 0.1382 0
7.10 Ratio of dynamic & Static force on supports VF= 0.6692 0 7.11 Ratio of stress for main conductor with & without
3 phase Auto reclosing VR=
1.529
7.12 Factor a 0.625 0
7.13 Dynamic force (Bending Force) Fd = 136.94 0
7.14 Total Dynamic force due to Left span = 136.94 kg
TYPICAL SHORT CIRCUIT FORCE CALCULATION FOR 400kV
BUS POST INSULATOR
Total Fd (Kg) Left Right Left Right Left Right Left Right Left Right Left Right Left Right Left Right Left Right FIXED SIMPLE SIMPLE FIXED 9 10.5 4.19 8.1 110.8 214.18 25.8 6.91 1.0128 0.6692 1.176 1.529 82.505 82.1638 SIMPLE SIMPLE FIXED FIXED 12 9 9.315 4.189 246.3 110.77 5.22 25.84 0.5964 1.0129 1.603 1.176 88.317 49.4919 FIXED SIMPLE SIMPLE FIXED 12 5.5 9.318 2.827 246.4 74.753 5.22 56.73 0.5962 1.8 1.603 1 147.22 50.458 FIXED 0 SIMPLE 0 10.5 0 8.1 0 214.2 0 6.91 0 0.6692 0 1.529 0 136.94 0
TABLE 1. Bending Force on 400kV Equipments
Equipment Support Other Equipment Support Fd (Kg) Distance between Eqpts(m) Effective Length(m) Fm (Kg) fc (Hz) Vr VF