The website has a similar explanation, but doing it manually goes over my head lol.
VOLTAGE DROP
Voltage drop is given by the following formula :
Where :
U : Voltage of the DC or AC system (V)
This is phase-phase voltage for 3-phase system; phase-neutral voltage for single-phase system.
Example :
- For western European countries a 3-phase circuit will usually have a voltage of 400 V, and single-phase 230V.
- In North America, a typical three-phase system voltage is 208 volts and single phase voltage is 120 volts.
NB: for DC voltage drop in photovoltaic system, the voltage of the system is U = Umpp of one panel x number of panels in a serie.
ΔU : voltage drop in Volt (V)
b : length cable factor, b=2 for single phase wiring, b=1 for three-phased wiring.
ρ1 : resistivity in ohm.mm2/m of the material conductor for a given temperature. At 20 celcius degree °C the resistivity value is 0.017 for copper and 0.0265 for aluminium.
Note that resistivity increases with temperature. Resistivity of copper reaches around 0.023 ohm.mm2/m at 100 °C and resistivity of aluminium reaches around 0.037 ohm.mm2/m at 100 °C.
Usually for voltage drop calculation according to electrical standards it is the resistivity at 100°C that is used (for example NF C15-100).
ρ1 = ρ0*(1+alpha(T1-T0)), here ρ0 = resistivity at 20°C (T0) and alpha = Temperature coefficient per degree C and T1 = temperature of the cable.
T1 : Temperature of the cable (default value = 100°C).
Note that from experience, a wire with a correct sizing should not have an external temperature over 50°C, but it can correspond to an internal temperature of the material around 100°C.
L : simple length of the cable (distance between the source and the appliance), in meters (m).
S : cross section of the cable in mm2
Cos φ : power factor, Cos φ = 1 for pure resistive load, Cos φ< 1 for inductive charge, (usually 0.8).
λ : reactance per length unit (default value 0.00008 ohm/m)
Sin φ : sinus (acos(cos φ)).
Ib : current in Ampere (A)
NB : For DC circuit, cos φ=1, so sin φ=0.
Voltage drop in percent :
ΔU(%) = 100 x ΔU/U0
Where :
ΔU : voltage drop in V
U0 : voltage between phase and neutral (example : 230 V in 3-phase 400 V system)
VOLTAGE DROP
Voltage drop is given by the following formula :
Where :
U : Voltage of the DC or AC system (V)
This is phase-phase voltage for 3-phase system; phase-neutral voltage for single-phase system.
Example :
- For western European countries a 3-phase circuit will usually have a voltage of 400 V, and single-phase 230V.
- In North America, a typical three-phase system voltage is 208 volts and single phase voltage is 120 volts.
NB: for DC voltage drop in photovoltaic system, the voltage of the system is U = Umpp of one panel x number of panels in a serie.
ΔU : voltage drop in Volt (V)
b : length cable factor, b=2 for single phase wiring, b=1 for three-phased wiring.
ρ1 : resistivity in ohm.mm2/m of the material conductor for a given temperature. At 20 celcius degree °C the resistivity value is 0.017 for copper and 0.0265 for aluminium.
Note that resistivity increases with temperature. Resistivity of copper reaches around 0.023 ohm.mm2/m at 100 °C and resistivity of aluminium reaches around 0.037 ohm.mm2/m at 100 °C.
Usually for voltage drop calculation according to electrical standards it is the resistivity at 100°C that is used (for example NF C15-100).
ρ1 = ρ0*(1+alpha(T1-T0)), here ρ0 = resistivity at 20°C (T0) and alpha = Temperature coefficient per degree C and T1 = temperature of the cable.
T1 : Temperature of the cable (default value = 100°C).
Note that from experience, a wire with a correct sizing should not have an external temperature over 50°C, but it can correspond to an internal temperature of the material around 100°C.
L : simple length of the cable (distance between the source and the appliance), in meters (m).
S : cross section of the cable in mm2
Cos φ : power factor, Cos φ = 1 for pure resistive load, Cos φ< 1 for inductive charge, (usually 0.8).
λ : reactance per length unit (default value 0.00008 ohm/m)
Sin φ : sinus (acos(cos φ)).
Ib : current in Ampere (A)
NB : For DC circuit, cos φ=1, so sin φ=0.
Voltage drop in percent :
ΔU(%) = 100 x ΔU/U0
Where :
ΔU : voltage drop in V
U0 : voltage between phase and neutral (example : 230 V in 3-phase 400 V system)
