Panel Design / Calculate Size of Bus bar Bus bar Details
Bus bar Current Details:
Rated Voltage (L-L):
Rated Frequency:
Desire Maximum Current Rating :
Fault Current (Isc):
Fault Duration (t):
415
50
630
50
1
Bus bar Temperature Details:
Operating Temperature of Bus bar (θ)
Final Temperature of Bus bar during Fault(θ1)
Temperature rise of Bus Bar Bar during Fault (θt=θ1-θ)
Ambient Temperature(θn):
Maximum Bus Bar Temperature Rise:
85
185
100
50
35
Enclosure Detail:
Type of Panel
Installation of Panel
Altitude of Panel Installation on Site
Panel Length
Cubical Type
Indoors (well Ventilated)
2200
1200
Panel W idth
600
Panel Height
2400
Panel Area:
1728000000
Bus bar Detail:
Bus bar Material
Bus bar Shape
Bus bar Strip Arrangements
Current Density of Bus Bar Material
Temperature Co efficient of Material Resistance at 20°c(α20):
Material Constant(K):
# Bus bar Material Permissible Strength:
Bus bar Insulating Material:
Bus bar Position:
Bus bar Installation Media:
Bus bar Artificial Ventilation Scheme:
Copper
Flat Bars
Vertical
1.6
0.00403
1.166
1200
Ba r e
Edge-mounted bars
Non-ventilated ducting
without artificial ventilation
Bus bar Size Detail:
Busbar W idth(e):
75
Busbar Thickness(s):
10
Number of Bus Bar per Phase(n):
Total Busbar Area per Phase:
Busbar Length per Phase(a):
Distance between Two Bus Strip per Phase(e):
Busbar Phase Spacing (p):
Total width of Bus bar per Phase(w):
# Busbar Phase to Phase Distance (d):
Modulus of inertia of a busbar or of a set of busbars
Total No of Circuit
Total Busbar Area for Enclosure
Busbar Support Insulator Detail:
2
1500
500
75
400
225
625
14.45
3
9000000
# Distance between insulators on Same Phase(l):
# Insulator Height (H)
Distance from the head of the insulator to the busbar centre of
1
gravity (h):
# Permissible Strength of Insulator (F'):
Indoors (well Ventilated)
Indoors (Poorly Ventilated)
Outdoor Flat Bars
Round Bars
Hollow Round Bars
Bare
PVC Sleeving
Painted
Edge-mounted bars
1 bar base-mounted
several base-mounted bars
Calm indoor atmosphere
Calm outdoor atmosphere
Non-ventilated ducting
without artificial ventilation
with artificial ventilation
Horizontal
Vertical
500
100
5
1000
Jignesh.Parmar, www.electricalnotes.wordpress.com,jiguparma r@yahoo.c
Bus bar Size Calculation
De rating Factors
Volt
Hz
Amp
KA
Sec
Per Phase Bus Strip De rating Factor (K1)
Busbar Insulating Material De rating Factor (K2)
Busbar Position De rating Factor (K3)
Busbar Installation Media De rating Factor (K4)
Busbar Artificial Ventilation De rating Factor (K5)
1.83
1
1
0.8
0.9
Enclosure & Ventilation De rating Factor (K6)
0.95
°c
°c
°c
Proxy Effect De rating Factor (K7)
Altitude of Bus Bar installation De rating Factor (K8)
Total Derating Factor:
0.82
0.88
0.90
°c
°c
Busbar Size Calculation
2
Meter mm
Desire Current Rating of Busbar (I2)
630
Current Rating of Busbar after Derating Factor (I1)
Busbar Cross Section Area as per Current
Busbar Cross Section Area as per Short Circuit
697
436
626
Final Calculated Bus Bar Cross Section Area
626
Actual Cross Section Area of Busbar
1500
mm
Bus Bar Size is OK
mm
Forces generated on Bus Bar due to Short Circuit Current
Sq.mm
Peak electro-magnetic forces between phase conductors (F1)
250
Peak electro-magnetic forces between phase conductors (F1)
2.5
Forces at the head of the Supports or Bus Bar (F)
Permissible Strength of Insulator (F') is
3
10
Forces on Insulation is in within Limits
A/Sq.mm
Mechanical strength of the busbars
Kg/cm2
Mechanical strength of the busbars
Mechanical strength of the busbars
Permissible Busbar Strength is
72
0.7
12
Mechanical strength of Busbar is in within Limit
Temperature Rise Calculation
Specified Maximum Temperature Rise (T1)
Calculated Maximum Temperature Rise (T2)
Temperature Rise is in within Limit
mm
mm
Results:
No's
Sq.mm
mm
mm
mm
mm
mm
cm3
Size of Busbar: 2 Nos X 75 X 10 Per Phase
Total No's of Busbar: 6 Nos X 75 X 10 for Phase and 1 Nos X 75 X 10 Per Neutral
Forces at the head of the Supports or Bus Bar (F) :2.625Kg/mm 2
Mechanical strength of the busbars :0.7Kg/mm2
Maximum Temperature Rise :30°c
Sq.mm
35
30
mm
mm
mm
Kg/cm2
Ref: Merlin Gerin design guide
m
0.15
0.52%
2
Amp
Amp
Sq.mm
Sq.mm
Sq.mm
Sq.mm
Kg/cm2
Kg/mm2
Kg/mm2
Kg/mm2
Kg/cm2
Kg/mm2
Kg/mm2
°c
°c
1
Various Derating Factor Number of Bus bar Strip per Phase (K1)
e/a
No of Bus bar per Phase
2
1.63
0.05
1
1
3
2.4
0.06
1
1.73
2.45
0.08
0.1
0.12
1
1
1
1.76
1.8
1.83
2.5
2.55
2.6
0.14
1
1.85
2.63
0.16
0.18
0.2
1
1
1
1.87
1.89
1.91
2.65
2.68
2.7
Volume of Enclosure & Ventilation De rating Factor (K6)
cross Section area of
Busbar/Total Bus bar Area
0%
Indoors ( Panel is well
Ventilated)
0.95
Indoors ( Panel is Poorly
Ventilated)
0.85
1%
5%
10%
0.95
0.9
0.85
0.85
0.7
0.65
Value of Modulus of inertia of a bus bar or of a set of bus bars (i/v)
No of Bus Strip per Phase
1
2
3
Vertical Bus Bar (cm3)
1.66
14.45
33
Horizontal Bus Bar (cm3)
16.66
33.33
50
Outdoor 0.65
0.65
0.6
0.5
2
2
14.45
Bus bar Insulating Material (K2):
Bare
PVC Sleeving
Painted
De rating Factor 1
1.2
1.5
Bus bar Position(K3):
Edge-mounted bars
1 bar base-mounted
several base-mounted bars
Bus bar Installation Media(K4):
Calm indoor atmosphere
Calm outdoor atmosphere
Non-ventilated ducting
Bus bar Artificial Ventilation Scheme (K5):
without artificial ventilation
with artificial ventilation
De rating Factor 1
0.95
0.75
De rating Factor 1
1.2
0.8
De rating Factor 0.9
1
Altitude of installation site (Meter) (K8)
De rating Factor 2200
2400
2500
2700
0.88
0.87
0.86
0.85
2900
0.84
3000
3300
3500
4000
4500
5000
0.83
0.82
0.81
0.78
0.76
0.74
Proxiy Effect (K7):
1
2
3
4
5
6
7
De rating Factor 0.82
0.82
0.82
0.89
0.95
0.99
1