Planning with SIVACON 8 PS - Siemens

Further information about planning 77.1 Dimensioning and selection7.1.1 Determining the voltage dropFormula for voltage dropWith long trunking runs it may be necessary to calculate the voltage drop: ΔUIBlkR1X1cos φ= voltage drop (V)= rated current (A)= total length of system (m)= load distribution factor= ohmic resistance (mΩ/m) with busbar final heating= inductive resistance (mΩ/m) with busbar final heating= power factorThe load distribution factor k for calculating the voltage drop at the end of the busbartrunking system is defined as follows:● k = 1, if the load is concentrated at the end of the busbar trunking system (powertransmission).● k = (n +1)/(2 x n), if the load is distributed across n taps.To calculate the voltage drop in the distance d between the start of a tap and the start of thebusbar system, proceed as follows:● k = (2 x n + 1 – n x d/L)/(2 x n)Planning with SIVACON 8 PSPlanning Manual, 10/2007, A5E01541101-01 233