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# Electric Power

It covers articles related to single and three phase power.

## Three-Phase AC Power: Star & Delta Connection

The most economical way to mass produce AC power is by steam turbines that drive large three-phase AC generators (alternators — Figure 1). Figure 1. Steam turbines drive large 3-phase AC generators This is why most electrical-utility power generating plants are located on a river that has been dammed to …

## Single-Phase AC Power

In a single-phase (or 3-phase for that matter) AC electrical power distribution system, both the load current (as electrical utilization loads are connected) and the applied voltage that causes it to flow are transmitted along the length of the circuit conductors varying in amplitude with time and periodically reverse between …

## High-Voltage DC Power Transmission

Advantages and disadvantages of a High-Voltage DC power transmission system should be analyzed in detail. Only then can we raise the question: Is AC energy transmission the most efficient option for the 21st century? AC energy transmission is the most common mode of energy transmission in the world. DC transmission …

## Solar Energy System Cost

A general method of calculation will start from the load energy requirements; determine the local insolation level and the worst month insolation and from this determine the sizing of the storage capacity. From this follows the array power and area, the battery capacity, and eventually the voltage regulator size respectively, …

## Uninterruptible Power Supply (UPS): How It Works | Uninterruptible Power Supply Types

One method of protecting sensitive equipment against power interruptions is the uninterruptible power supply (UPS). The UPS has become very popular as the cost of power electronics has decreased. Uninterruptible Power Supply Working Figure 1 shows the principles of operation of an electronic UPS. Single- or three-phase power is obtained …

## Where do harmonics come from | Causes of Harmonics in Power System

Any electrical load that does not have a linear relationship between the voltage applied to it and the current through it will cause harmonic currents in the power system. To consider what is meant by a linear load, consider Figure 1. Figure 1(a) shows a sinusoidal voltage and the current …

## Harmonics in Power System

Ideally, all voltages and currents in the power system should be single-frequency sinusoids (60 Hz in North America). The actual power system, however, contains voltage or current components, called harmonics, whose frequencies are integral multiples of the power system frequency. The second harmonic for a 60 Hz system is 120 …

## Load Profile Calculation | Solved Example

The load profile is an approximation of the aggregate energy required from a power system over a particular time period (e.g., years, days, hours). The load profile is demonstrated in a two-dimension graph exhibiting the instantaneous load (in Volt-Amperes) over a certain period of time and presents an easy way …

## Solar PV System Sizing: Step By Step Guide

This particular article talks about the standalone solar photovoltaic (PV) system sizing. Standalone PV systems are primarily utilized for providing power to small, remote areas where it’s impractical to lay down a transmission line or even have some alternative generation option like diesel generators. Though this article focuses mainly towards …

## Difference between Traditional Power Grid and Smart Grid

The traditional power grid is basically the interconnection of various power systems elements such as synchronous machines, power transformers, transmission lines, transmission substations, distribution lines, distribution substations, and different types of loads. They are located far from the power consumption area and electric power is transmitted through long transmission lines. …

## Smart Grid Technology and Applications | Smart Grid Components

Now a day, we are often hearing about smart grid, in the news and around all of us too but most of the people do not have the basic understanding of what a smart grid really is? Just because the word ‘smart” has been attached to it, do not assume …

## Double Subscript Notation in Single Phase System

In single phase electric power, the double-subscript notation eliminates the need for both the polarity markings for voltages and direction arrows for currents. It is even more useful for representing voltages and currents in three-phase circuits, resulting in greater clarity and less confusion. Voltage Phasor The voltage phasor with double …

Delta Connection In Delta connection, phase sides are connected in a cyclical arrangement in order to make a closed loop as shown in figure 1. As far as line and phase currents are concerned, they are related to each other as: ${{\text{I}}_{\text{line}}}\text{=}\sqrt{\text{3}}{{\text{I}}_{\text{phase}}}$ Which means that whatever supply current we have, …