Bus bar Current Details:

Rated Voltage = 415 V

Frequency = 50 Hz
Desire Maximum Current Rating of Bus bar = 630 Amp
Fault Current (Isc) = 50 KA
Fault Duration (t) = 1 Sec
Bus bar Temperature details:
Operating Temperature of Bus bar (θ) = 85 °C.
Final Temperature of Bus bar during Fault(θ1) = 185 °C.
Temperature rise of Bus Bar Bar during Fault (θt=θ1-θ) = 100 °C.
Ambient Temperature (θn) = 45 °C.
Maximum Bus Bar Temperature Rise = 55 °C.
Enclosure Details:
Installation of Panel = Indoors (well Ventilated)
Altitude of Panel Installation on Site = 800 Mtr
Panel Length = 2500 mm
Panel width = 600 mm
Panel Height = 2400 mm
Bus bar Details:
Bus bar Material= Copper = Aluminium
Bus bar Strip Arrangements= Vertical = Vertical
Current Density of Bus Bar Material = 0.8
Temperature Co efficient of Material Resistance at 20°c(α20) = 0.00386
Material Constant(K) = 1.166
Bus bar Material Permissible Strength = 1200 kg/cm2
Bus bar Insulating Material= Bare = Bare
Bus bar Position = several base-mounted bars
Bus bar Installation Media = Non-ventilated ducting
Bus bar Artificial Ventilation Scheme = without artificial ventilation
Bus bar Size Details:
Bus bar Width ( e ) = 75 mm
Bus bar Thickness (s) = 10 mm
Number of Bus Bar per Phase (n) = 1 No
Bus bar Length per Phase (a) = 2300 mm
Distance between Two Bus Strip per Phase ( e ) = 10 mm
Bus bar Phase Spacing (p) = 300 mm
Total No of Circuit = 15 No
Bus bar Support Insulator Detail:
Distance between insulators on Same Phase (l) = 100 mm
Insulator Height (H) = 100 mm
Distance from the head of the insulator to the bus bar center of gravity (h) = 5 mm
Permissible Strength of Insulator (F’) = 1000 kg/cm2

(1) Per Phase Bus Strip De rating Factor (K1):

Bus bar Width(e) is 75mm and Bus bar Length per Phase(a) is 2300mm so e/a is = 0.032608696 mm
No of Bus bar per phase is = 1 No
From following table value of de rating factor is = 1.86
(2) Bus bar Insulating Material De rating Factor (K2)
Bus bar insulating material = Bare
De rating Factor is = 1
(3) Bus bar Position De rating Factor (K3)
Bus bar Position is = several base-mounted bars
De rating Factor is = 0.75
(4) Bus bar Installation Media De rating Factor (K4)
Bus bar Installation Media is = Non-ventilated ducting
De rating Factor is = 0.8
(5) Bus bar Artificial Ventilation De rating Factor (K5)
Bus bar Installation Media is = without artificial ventilation
De rating Factor is = 0.9
(6) Enclosure & Ventilation De rating Factor (K6)

Bus bar Area per Phase = Bus width X Bus Thickness X Length of Bus X No of Bus bar per Phase = 1725000

Total Bus bar Area for Enclosure= No of Circuit X( No of Phase + Neutral )X Bus bar Area per Phase = 103500000

Total Enclosure Area= width X Height X Length = 3600000000

Total Bus bar Area for Enclosure / Total Enclosure Area = 2.88%
Bus bar Artificial Ventilation Scheme is without artificial ventilation De rating Factor is = 0.95

(7) Proxy Effect De rating Factor (K7)

Bus bar Phase Spacing (p) is 300mm. = 300
Total Bus length of Phase with spacing = 75
Bus bar Phase Spacing (p) / Total Bus length of Phase with spacing = 4.000
From following Table De rating factor is = 0.89
(8) Altitude of Bus Bar installation De rating Factor (K8)
Altitude of Panel Installation on Site is 800 meter so following Table = 800
De rating Factor is = 0.96
Total De rating Factor= K1XK2XK3Xk4Xk5Xk6Xk7Xk8 = 0.82
(2) Bus bar Size Calculation:
Desire Current Rating of Bus bar (I2) = 630 Amp
Current Rating of Bus bar after De rating Factor (I1)= I2 x De rating Factor = 514 Amp
Current Rating of Bus bar after De rating Factor (I1)=514Amp

Bus bar Cross Section Area as per Current= Current Rating of Bus bar / Current Density of Material = 643 sqmm

Bus bar Cross Section Area as per Current= 643 Sq.mm

Bus bar Cross Section Area as per Short Circuit= Isc X√ ((K/( θtx100)x(1+ α20xθ) xt = 622 sqmm

Bus bar Cross Section Area as per Short Circuit 622 Sq.mm
Final Calculated Bus Bar Cross Section Area 643 Sq.mm = 643 sqmm
Actual Selected Bus bar size is = 750 sqmm
Actual Bus bar cross section Area per Phase = 750 sqmm
Actual Bus bar Size is Less than calculated Bus bar size.
(3) Forces generated on Bus Bar due to Short Circuit Current

Peak electro-magnetic forces between phase conductors (F1) = 2X(l/d)X(2.5xIsc)2/100000000 = 83 Kg/cm2

Total width of Bus bar per Phase(w) = 7.5 Cm

Bus bar Phase to Phase Distance (d) = 37.5 Cm
Peak electro-magnetic forces between phase conductors (F1) = 0.83 Kg/mm2
Actual Forces at the head of the Supports or Bus Bar (F)=F1X(H+h)/H = 0.88 Kg/mm2
Permissible Strength of Insulator (F’) is 10 Kg/mm2 = 10 Kg/mm2
Actual Forces at the head of the Supports or Bus Bar is less than Permissible Strength Forces on Insulation is in within Limits
(4) Mechanical strength of the bus bars

Mechanical strength of the bus bars=(F1X i /12)x(1/ Modulus of inertia of a bus bar ) = 962 Kg/cm2

From above table Value of Modulus of inertia of a bus bar=14.45 = 1.66 CM2

Mechanical strength of the bus bars = 9.62 Kg/mm2

Permissible Bus bar Strength is = 12 Kg/mm2
Actual Mechanical Strength is less than Permissible Strength Mechanical strength of Bus bar is in within Limit
(5) Temperature Rise Calculation
Specified Maximum Temperature Rise (T1) is 35 = 40 °C
Calculated Maximum Temperature Rise (T2)=T x (I1/I2)^1.7) = 28.30 °C
Calculated Maximum Temperature Rise (T2)= 30°c
Calculated Bus bar Temperature rise is less than Specified Max Temperature rise Temperature Rise is in within Limit