In this part of the discussion about voltage drop calculation. We shall be providing real world example for you to be able to appreciate it better as it may have already been a part of what you have already done or currently doing in your design.
An IEC standard equipment will be presented in our sample calculation.
A 120 mm2 3core XLPE insulated cable 120m in length supplies a 110 kW induction motor that has a starting current of 6 times the full-load current of 180 amps. The starting power factor is 0.25 lagging.
If the sending end line-to-line voltage is 400 volts, the specific resistance r and reactance x for the cable are 0.197 and 0.072 ohm/km respectively at 90OC and 50 Hz.
Let us calculate for the percentage volt-drop during motor starting.