Electric power

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Electric power is the rate, per unit time, in which electrical energy is transferred by an electrical circuit. The SI unit of power is watts, one joule per second.

Electric power is usually produced by electric generators, but can also be supplied by sources such as electric batteries. Usually supplied to businesses and homes by the power industry through power grids. Electric power is usually sold with kilowatt hours (3.6 MJ) which is a power product in kilowat multiplied by the running time in hours. Electric utilities measure power using an electric meter, which stores the total electrical energy delivered to the customer.

Electrical power provides a low form of entropy energy and can be done in long distances and converted into other forms of energy such as motion, light or heat with high energy efficiency.

Video Electric power

Definisi

Electric power, such as engine power, is the speed of work, measured in watts, and represented by the letter P . The term watt is used in everyday language to mean "electric power in watts." The power in the watts generated by the electric current I consists of charge Q coulombs per t seconds passing through the potential power (voltage) V is

${\ displaystyle P = {\ text {job completed per unit time}} = {\ frac {VQ} {t}} = VI \,} Â Â$

Where

Q is the electrical charge in the coulomb

t is the time in seconds

I is an electric current in amperes

V is the electrical potential or voltage in volt

Maps Electric power

Description

Electric power is converted into another form of energy as the electrical charge moves through the differential (voltage) electrical potential, which occurs in electrical components in the electrical circuit. From a power point standpoint, the components in the electrical circuit can be divided into two categories:

• Passive device or load : As the electrical charge moves through the potential difference from higher to lower voltage, ie when conventional (positive charge) currents move from positive terminal () to the negative terminal (-), the work is done by the cost of the device. The potential energy of the load due to the voltage between the terminals is converted to kinetic energy in the device. This device is called passive component or load ; they 'consume' electricity from the circuit, converting it into other forms of energy such as mechanical work, heat, light, etc. Examples are electrical equipment, such as light bulbs, electric motors, and electric heaters. In alternating current (AC) circuits the voltage direction periodically reverses, but the current always flows from a higher potential to the lower potential side.

• Active device or resource : If the charge is moved by 'exterior power' through the device in the direction of lower down potential electricity (moving positive charge from negative to positive terminal), work will be done at cost, and energy is converted into electrical potential energy from some other kind of energy, such as mechanical energy or chemical energy. The device where this happens is called an active device or resource ; such as electric generators and batteries.

Some devices can be either source or load, depending on the voltage and current through it. For example, a rechargeable battery acts as a source when providing power to the circuit, but as a load when connected to a charger and is being recharged, or a generator as a power source and a motor as a load.

Passive sign convention

Because electric power can flow in and out of a component, a convention is required for which direction represents a positive power flow. The electric power that flows out from the circuit to the component is defined as having to have a positive sign, while the electric current to the circuit of the component is defined as having a negative sign. Thus the passive component has a positive power consumption, while the power source has a negative power consumption. This is called passive sign convention .

Resistive circuit

Dalam kasus beban resistif (Ohmic, atau linier), hukum Joule dapat dikombinasikan dengan hukum Ohm ( V = IÂ · R ) untuk menghasilkan ekspresi alternatif untuk jumlah kekuatan yang dihamburkan:

${\ displaystyle P = IV = I ^ {2} R = {\ frac {V ^ {2}} {R}},}  ÂÂ$

where R is an electrical resistance.

Alternating current

In alternating current circuits, energy storage elements such as inductance and capacitance can produce periodic energy flow reversals. The portion of the power flow which, on average over the complete cycle of AC waves, results in the transfer of clean energy in one direction known as real power (also referred to as active power). Part of the power flow because of the stored energy, which returns to the source in each cycle, is known as the reactive power. The real power P in the watts consumed by the device is given by

$Â\; Â{\displaystyle Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; ÂPÂ\; Â\; Â\; Â\; Â\; Â\; Â\; Â=Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; ÂÂ\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\frac{}{}Â\; Â\; Â\; Â\; Â\; Â\; Â\; ÂÂ\; Â\; Â\; Â\; Â\; Â\; Â}$ _{         V                Â ·                                    I                Â ·                            cos                 ?         =                 V                 Â      Â      ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂﯯ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ï <½ï <½ï <½ï <½ï <½ï <½ï <½ï <                                   I                 Â      Â      ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂﯯ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ï <½ï <½ï <½ï <½ï <½ï <½ï <½ï <                           cos                 ?                       {\ displaystyle P = {1 \ over 2} V_ {p} I_ {p} \ cos \ theta = V_ {rms} I_ {rms} \ cos \ theta \,}  Â}

Where

V _p is the peak voltage in volts

I _p is the peak current in amperes

V _rms is the root-mean-square voltage in volts

I _rms is the root-mean-square current in ampere

? is the phase angle between the current and the sine wave voltage

The relationship between real strength, reactive power and real power can be expressed by representing quantity as a vector. Real power is represented as a horizontal vector and reactive power is represented as a vertical vector. The apparent power vector is the oblique side of the right triangle formed by connecting the real and reactive power vectors. This representation is often called the triangle of strength . By using the Pythagoras Theorem, the relationship between real, reactive and clear forces is:

${\ displaystyle {\ mbox {(apparent power)}} ^ {2} = {\ mbox {(real power)}} ^ {2} {\ mbox {(reactive power)}} ^ {2}}$

Kekuatan nyata dan reaktif juga dapat dihitung langsung dari daya semu, ketika arus dan tegangan keduanya sinusoid dengan sudut fase yang diketahui? diantara mereka:

${\ displaystyle {\ mbox {(kekuatan nyata)}} = {\ mbox {(daya semu)}} \ cos \ theta}  ÂÂ$

${\ displaystyle {\ mbox {(daya reaktif)}} = {\ mbox {(daya semu)}} \ sin \ theta}  ÂÂ$

The ratio of apparent power to pseudo power is called the power factor and is a number always between 0 and 1. Where currents and voltages have non-sinusoidal shapes, the power factor is generalizable to include distortion effects

Electromagnetic fields

The flow of electrical energy wherever the electric and magnetic fields are together and fluctuate in the same place. The simplest example is in the electrical circuit, as shown by the previous section. However, in the general case, the simple equation P = IV should be replaced by a more complicated calculation, the integral of the cross product of the electric field vector and the magnetic field. in a certain area, so:

$Â\; Â{\displaystyle Â\; Â\; Â\; Â\; Â\; Â\; Â\; Â\; ÂPÂ\; Â\; Â\; Â\; Â\; Â\; Â\; Â=Â\; Â\; Â\; Â\; Â\; Â\; Â}$ _{          ?            S                         (                   E                ÃÆ' -                   H                )         ?                   d          A                 .                       {\ displaystyle P = \ int_ {S} {\ mathbf {E} \ times \ mathbf {H}) \ cdot \ mathbf {dA}. \,}  Â}

The result is a scalar because this is the surface integral of the Poynting vector .

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Generation

The fundamental principles of many power plants were discovered during the 1820s and early 1830s by the English scientist Michael Faraday. The basic method is still used today: electricity is generated by wire loop movements, or copper disks between magnetic poles.

For electric utilities, it is the first process in delivering electricity to the consumer. Other processes, power transmission, distribution, and storage of electrical power and recovery using pumped storage methods are usually carried out by the power industry.

Electricity is mostly generated at power plants by electromechanical generators, driven by heat engines heated by combustion, geothermal power or nuclear fission. Other generators are driven by kinetic energy from running water and wind. There are many other technologies used to generate electricity such as photovoltaic solar panels.

Batteries are devices consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first (or "voltaic pile") battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, the battery has become a common source of electricity for many household and industrial applications. According to 2005 estimates, the battery industry worldwide generates US $ 48 billion in sales annually, with annual growth of 6%. There are two types of batteries: primary batteries (disposable batteries), designed to be used once and discarded, and secondary batteries (rechargeable batteries), which are designed to be recharged and used multiple times. Batteries come in a variety of sizes, from mini cells used for hearing aid power and watches to battery-sized battery chambers that provide standby power for telephone exchange and computer data centers.

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Power industry

The electric power industry provides the production and delivery of energy, in sufficient quantities to areas requiring electricity, through a network connection. Grid distributes electrical energy to customers. Electric power is generated by a central power plant or by a distributed generation. The power industry is gradually tending toward deregulation - with the emergence of players offering consumer competition with traditional public utility companies.

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Use

Electric power, generated from central generating stations and distributed over power transmission lines, is widely used in industrial, commercial and consumer applications. The per capita power consumption of a country is correlated with the development of the industry. Electric motors produce electric machines and push the subway and train rail. Electric lighting is the most important form of artificial light. Electrical energy is used directly in processes such as aluminum extraction from the ore and in the production of steel in an electric arc furnace. Reliable power is essential for telecommunications and broadcasting. Electric power is used to provide air conditioning in hot climates, and in some places electric power is an economically competitive energy source for heating the room. The use of electric power for pumping water ranges from individual household wells to irrigation projects and energy storage projects.

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See also

• EGRID
• Electric energy consumption
• Power system
• High voltage cable
• Power techniques
• Power plant
• Rural electrification

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Note

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References

• Reports in August 2003, Blackout, American Electric Reliability Council website
• Croft, Terrell; Summers, Wilford I. (1987). American Electricians' Handbook (Eleventh). New York: McGraw Hill. ISBN: 0-07-013932-6.
• Fink, Donald G.; Beaty, H. Wayne (1978). Standard Handbook for Electrical Engineers (Eleven ed.). New York: McGraw Hill. ISBN: 0-07-020974-X.

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External links

• US. Department of Energy: Electric Power
• GlobTek, Inc. Glossary Terms of Power Supply

Source of the article : Wikipedia