Voltage Distribution by Standard Formula

       When the number of units is a string of suspension type of insulator increases, calculation of voltage across each unit and the string efficiency becomes tedious, laborious and time consuming by the method discussed earlier. In such a case, following formulae can be used.
Let     V = Voltage across string
          k= Ratio of shunt to mutual capacitance
          n = Number of units in the string

V₁ , V₂, V₃ … = Voltages across the units starting from the line unit. Note that V₁, V₂, V₃ …  are defined from bottom to top. Then voltages across x^th unit is given by, 

      While the string efficiency given by,