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# Electric Power

It covers articles related to single and three phase power.

## Phase Sequence in Three-Phase System

In a three-phase service supplied by an electrical utility company, all three line voltages have the same magnitude and are displaced from one another by 120°. We can measure the magnitude of these voltages quite readily. However, the magnitudes do not tell us whether VBN leads VAN by 120° or …

The two-phase alternator in Figure 1(a) has two identical loops mounted on the same rotor. Since both loops have the same number of turns and rotate at the same angular velocity, the voltages induced in them have the same magnitude and frequency. Loop A is mounted on the rotor 90° …

## Power Triangle and Power Factor in AC Circuits

Power Triangle The real power in the circuit of Figure 1 can be found from the product of VR and I, and the reactive power from the product of VL and I. Since VL leads VR by 90°, $\begin{matrix}{{V}_{T}}=\sqrt{V_{R}^{2}+V_{L}^{2}} & {} & \left( 1 \right) \\\end{matrix}$ Figure 1 AC circuit …

## AC AC Power Converter

For AC-to-AC conversion the voltage and/or the frequency are the parameters that might need to be increased or decreased. For voltage only, a transformer can be used. But, for the frequency change, and for both frequency and voltage change, use of electronic converters becomes necessary. Unidirectional Back-to-Back Converters The key …

## Transmission Line Effects

This section briefly describes matters concerned with transmission lines in electrical networks. Knowledge of the material described here is very useful for the technical personnel in electricity and its generation and distribution. Inductive and Capacitive Effect In addition to the ohmic resistance in the wires and electric conductors, conductors carrying …

## Fault Detection in Transmission Lines

Faults in an electric system can happen because of various reasons. Some faults in electrical distribution are due to natural causes such as lightning and are inevitable. Others can be due to deterioration of components as a result of age or abuse, and so on. What is important in operation …

## Electric Cable

Electric cables or conductors are basically of two types, but each type has numerous categories. Conductors are either for overhead transmission lines or for underground installation. Overhead conductors are bare wire and do not have insulation except at residential areas where contact with trees and other objects is possible, whereas underground …

## Transmission Lines and Substation Types

Transmission lines are used to transmit electrical energy over relatively long distances. There are three types of transmissions lines: overhead, underground and sub-transmission. Overhead Transmission Line Overhead transmission lines are used to transmit electrical energy in the form of three phases (3 AC. A basic transmission line system is represented …

## How Do Power Plants Work?

The common theme of this topic is the concept of a prime mover (source of mechanical energy) driving a dynamo (alternator or generator) that converts mechanical energy to electrical energy. Furthermore, we take a look at the basic working principle of common power generating plants. Hydroelectric Plants A Hydroelectric Plant …

## Distributed Generation

In this section, we look at small-scale power generation. As time goes on, you will encounter this approach to generating power, called distributed generation, more and more. Definition: Distribution Generation (DG) is the production of small-scale power near or at a customer’s site. Distributed generation has many potential benefits, such …

## Residential Electrical Circuit

In this article, we will look at how residential service entrances, switches, and receptacles are connected to form the basic residential electrical circuit. Conductor Most residential electrical circuits utilize one of the conductor combinations identified in Table 1. The conductor combinations listed are illustrated in Figure 1. Table 1: Conductor …

## Service Entrance and Service Drop

Power enters the drop through the Service Entrance. The service entrance includes the Electric Meter that measures the amount of energy delivered to the home and the Service Panel that houses the circuit breakers or fuses. The service panel also distributes power to the various circuits in the house. Service …

A three-phase load is a set of three exactly similar combinations of electric components arranged in exactly the same way (in series, parallel or other). The reason to have three-phase loads is the higher power demand. For instance, in the industry, the majority of motors are three phase, particularly the …