ABSTRACT
Early distribution systems consisted of loads that were primarily lighting. Much of the utilities load is motor load, which contains reactive power requirements. This low power factor reactive load can cause voltage drop and losses which are largely unnecessary. Today, most distribution lines are thermally limited, i.e., the maximum current the line can carry without burning down is reached before voltage drop became a problem. This is possible because modern distribution systems generally have shorter feeders and higher voltages. Voltage drop on these lines certainly still exists, but with most utilities extensive use of capacitors limits line loss. The addition of a capacitor to an inductive system decreases voltage drop since the in-phase drop produced across the line by the capacitor is in the opposite direction to the voltage drop produced by load across the resistance and reactance. This is one of the reasons that the distribution system should not allow the power factor to exceed unity.
