90% of the industrial load is made up of induction machines (1-ϕ & 3-ϕ). Such machines use magnetizing current to generate the magnetic field, resulting in a low power factor.
Induction motors have exceptionally low pf (0.2 - 0.3) at small loads and 0.8 to 0.9 at full loads.
Inductive loads draw a trailing current, resulting in a low power factor.
Other inductive machinery, such as transformers, generators, arc lights, and electric furnaces, also work at low pf levels.
Differences in Power System Loading
Today, we have integrated power grids. The electricity system’s loading conditions change depending on the season and time. There are peak and low load periods.
When the system is lightly loaded, both the voltage & the current drawn by the machines increase. This produces a poor power factor.
Harmonic Currents
The existence of harmonic currents in the system also affects its power factor.
Improper wiring (or) electrical accidents can lead to a problem called 3-ϕ power imbalance. This leads in a poor power factor.
Capacitive Loads
Capacitive loads, like capacitors, can increase power factor and generate reactive power. On the other end, overcompensation and a leading power factor may result from an excessively high capacitance. A pure capacitive load has a power factor of zero.
Magnetizing Current
A power system’s load fluctuates. The supply voltage increases when there is minimal load, which increases magnetizing current & lowers the power factor.
Undersized Wiring
Inadequate wiring, particularly in motor windings, can result in voltage dips and increase the system’s reactive power, both of which can reduce power factor.
Long Distribution Lines
Long distribution lines have the potential to reduce power factor by increasing reactive power in the system and causing voltage drops.
