BUSBAR CALCULATION FOR CURRENT CARRYING CAPACITY 1000 A WITH 50 X 12 CU

BUSBAR DIMENSION CALCULATION FOR 1000 A Reference documents: Copper Development Association SWITCH BOARD REFERENCE : MAIN PCC - Busbar Rating - 1000 A 50 mm Thickness = 12 mm X 1 RUN Busbar dimensions: Width = 1. Approximate DC Current Rating for Single Flat Bars (Apply Formula 4, Page 11 ) As per Copper Development Association Hand Book, approximate current rating of busbar shall be carried out by following methods.

I=7.73x A0.5x p0.39 I A p

Formula 4 Page 11

= current carrying capacity, A = Busbar cross section area, mm2. = Busbar perimeter of conductor in mm.

Hence,

Idc = 7.73x600^.5x124^0.39 For Single Rectangular Section Bar = 1,241 A 2. Approximate AC current rating for Single flat bar 50 X 12 mm (Page 11, 13 & 37 ) Iac = Idc/(Rf/Ro)0.5 Ro1000 m = ∂20 * L/A A = cross section area, cm2 L = 1000 m ∂20 = resistivity of copper at 20 °C, 1.724 µΩ cm (Page 11) Ro1000 m = (1.724*100*1000)/(5.0*1.2) = 28733.3 µΩ Hence, (f/Ro)0.5 Rf/Ro (Rf/Ro)0.5

Where f - Frequenzy 50 Hz = (50*1000000/28733.33)0.5 = 42 1.12 (from page 13, Fig. 7) [Skin effect Ratio] = 0.5 = (1.12) 1.0583 =

Hence,

Iac = 1240.76/1.058301 Iac = For Single Rectangular Section Bar 1172 A 3. Approximate AC current rating for 1 No flat bars of 50 x 12 mm = 1172 A CONCLUSION: FINAL CURRENT CARRYING CAPACITY OF THE ABOVE BUSBAR IS SUFFICIENT TO CARRY THE REQUIRED BUSBAR RATING OF 1000 A.