What is the primary function of capacitors on power lines?

The primary function of capacitors on power lines is to improve the power factor. In power systems, inductive loads such as motors and transformers can cause the current to lag behind the voltage, leading to a lower power factor. A low power factor means that more current is needed to deliver the same amount of usable power, which can result in increased losses and reduce the efficiency of the power system.

Capacitors are used to counteract this effect because they provide reactive power (vars) to the system. By supplying leading current, capacitors help to balance the lagging current from inductive loads, effectively correcting the power factor. This results in reduced losses, improved voltage performance, and the ability to accommodate additional loads without needing to upgrade the infrastructure.

While capacitors can store energy, their primary role in this context is not to serve as energy storage devices, but rather to enhance power factor correction in the power distribution system.