# Capacitors in PE Power

Posted by Wasim Asghar on July 18th, 2024

Capacitors in PE Power are one of the most important exam topics. But why? The reason is their notable usage and importance in regulating and improving the Power circuits. Capacitors in PE Power involve studying their types, behavior, and uses in AC and DC circuits.

This detailed study guide on Capacitors in PE Power will help you cover this topic in complete detail as per the NCEES® exam guidelines and roadmap. Let’s start with the fundamentals.

## Capacitors and Their Importance in Power Circuits

A capacitor is a passive electronic component that stores electrical energy in an electric field. It consists of two conductors separated by an insulator, known as a dielectric.

The capacity of a capacitor to store charge is measured in farads (F). It is determined by the physical characteristics of the capacitor, including the area of the plates, the separation distance between the plates, and the dielectric material used.

Capacitors are used in circuits for various reasons. Let’s discuss a few important uses in a nutshell

Harmonic Mitigation with Capacitors: Capacitors are used in power systems to mitigate harmonics by creating resonant circuits that filter out specific harmonic frequencies. This is achieved by tuning the capacitor and inductor combinations to resonate at unwanted harmonic frequencies, thereby reducing their presence in the power system.

Capacitors and Voltage Fluctuations: Capacitors help stabilize voltage fluctuations in power systems by providing reactive power compensation. When connected to a power network, capacitors can absorb or release reactive power, which helps maintain a more consistent voltage level, especially in systems with fluctuating loads or significant inductive components.

Capacitors and Line Loss Reduction: By providing reactive power locally, capacitors reduce the need to transport reactive power over long distances in power lines, thus reducing line losses. This improves the efficiency of power transmission and distribution networks, as it decreases I²R losses (where I is current and R is resistance) in the conductors

## Types of Capacitors

Capacitors come in various types and classifications, each suited for specific applications and characteristics. Here’s a detailed overview of the different kinds and classifications of capacitors:

### · Electrolytic Capacitors

Aluminum Electrolytic Capacitors: They are known for their high capacitance-to-volume ratio; these capacitors use an aluminum oxide film and an electrolytic solution. They are polarized, meaning they must be connected with the correct polarity. Commonly used in power supply filtering applications.

Tantalum Electrolytic Capacitors: They are smaller and more stable than aluminum types; they have a lower risk of leakage and are more reliable. Tantalum capacitors are also polarized and are used in space-constrained applications like mobile phones and laptops.

### · Ceramic Capacitors

Multilayer Ceramic Capacitors (MLCCs): They are composed of alternating layers of metal and ceramic and offer a compact and non-polarized size. Used in a wide range of applications, from high-frequency to general electronic circuits.

Disc Ceramic Capacitors: They are often used for noise suppression and are non-polarized. They are suitable for relatively low capacitance requirements.