Voltage Drop Calculations
Cables and lines are the most important part of a system during planning and configuring. They must be able to withstand the mechanical and thermal stresses and transfer the power from connected equipment with as little loss as possible.
This requires the careful dimensioning of the electrical networks. Nowdays systems and household appliances are matched to the nominal voltage of the network. This may fluctuate only within established limits, since otherwise a normal power output cannot be ensured and the equipment can be destroyed.
This section discusses the voltage drop and the maximum line length for AC and three-phase networks, on the basis of the existing regulations and standards.
Cables and lines are the means of transfer which enables the transport and distribution of electrical energy, predominantly by way of AC and three-phase current. When an electrical current flows through a cable or a line, heat is generated and is defined according to:
P = I2R.
The amount of heat generated over a defined period of time is given by Q = I2 R t. This heat loss must be dissipated before the insulation is destroyed. The line resistance in a network is always assumed to be at 20°C.