I mean..
On transmission lines when the distance increases voltage gets decreased... so the time it reaches load it will be less than the required voltage level.. now how to get safe voltage

Good question:

Mechanical Voltage Regulator (http://www.ustpower.com/Support/Voltage_Regulator_Comparison/Mechanical_Voltage_Regulator.aspx)

Magnetic Induction Voltage Regulator Operation (http://www.ustpower.com/Support/Voltage_Regulator_Comparison/Mechanical_Voltage_Regulator/Magnetic_Induction_Voltage_Regulator_Operation.asp x)

Thank you...

Your welcome.