# Electric Power

Electric power is the measurement of electric energy flowing in the electric circuit per second. As the unit of measurement of energy is joules therefore the unit of measurement is joules per second. Though this unit of measurement of power is vastly used but as per the International System of Units (SI) the unit of measurement of electric power is specifically defined which is the watt (W). Electric generators are sources to generate electric power. These generators generate electrical power commercially and supply them for domestic and industrial use. Then power grids distribute this generated power.

Usage of electrical transmission lines to distribute the electric power over the long distances then come in the picture. This distributed electrical power is then used domestically and industrially for the generation of heat, light and to operate other electrical equipment either big or small in size or terms of consumption.

## Generation of Electric Power

Electrical current is the source of electric power. When a metal coil moves in the magnetic field the electric current generates. This method of generation of electric current is used to generate electricity commercially. There are two types of current, namely, Direct Current (DC) and Alternating Current (AC). When a direct current (I) passes over a potential difference (V) generates power (P). Mathematically,

P = V I

As we know that

V = I R, where R is the resistance

Then power, P is

P = $$I^{2}R$$ = $$\frac{V^{2}}{R}$$

In the case of alternating current, the AC voltage is expressed as root mean square voltage and power generated due to AC is expressed as time average power.

$$P_{time avg}$$ = $$\frac{{V_{rms}}^{2}}{R}$$

British scientist Michael Faraday’s principle for the generation of electric power is the basis of commercial production of electrical power. According to the Faraday’s principle, when a wire loop or disc of copper metal moves between the poles of a magnet electrical current generates.

Power stations use the same principle to produce electricity. They use very large electromagnets and copper coils for this purpose. These copper coils are inside the generators and these generators are driven by steam/heat engines which are, in turn, run by a jet of steam. There are other methods to rotate these generators like a stream of flowing water, wind, and steam generation by nuclear fission etc. The power produced by these methods is termed as hydropower, wind power and nuclear power respectively.

There is another method which nowadays very popular and high in demand for commercial production of electric power is Solar Power. Solar power uses photovoltaic panels to generate electricity. This type of electric power generation method creates zero air pollution.

Currently, the conventional method is in use to generate power. Lots of the power plants use the coal to get the steam from boiling water. These plants create too much air pollution in terms of ashes, carbon monoxide, carbon dioxide and other toxic effluents.

### Electric Power Industry

Commercial production of electric power was started from 1882. Earlier, distribution of electric power was in a limited area, but when the distribution lines started its use also increased exponentially. The main objective the electric power industries are to generate electricity, transmit and distribute over long distances and sale. Nowadays, electrical transmission lines are the artilleries of the growing economies.

Power plants generate electric power. This is transmitted to power substations through transmission lines. These power substations then distribute to end-users through distribution lines. The combination of this transmission and distribution network is known as the electric power grid. In India, it is the National Grid.

Electrical power transmission is done at the high voltage at a range of 2 kV to 35 kV to minimize the transmission losses. Then this voltage is reduced to distribute to end-users by using step-down transformers. These transformers reduce the voltage from 2 kV to 220 V. In India, most of the domestic electrical equipment works at this voltage. Excessive voltage can damage the equipment.

Most of the power plants generate the alternating current (AC) and distribute it in AC form. Alternating current is cheaper for production and easier for distribution as the energy loss is lower than direct current (DC). Alternating current can easily be step down or up in voltage than DC. Therefore AC is an easy option to distribute the electric power nationally, for long distances. For the household use of current, the power distribution agency supplies alternating current. The electronic instruments use DC to operate therefore, each instrument contains a chip to convert the supplied AC to usable DC.

Electric power has many advantages domestically and industrially, as most of the equipment run by electric power. Brightness in the night is only possible by the use of electricity. Almost all the factories and industries are running due to electric power. The advantage of electric power is its reliable and uninterrupted supply runs the equipment efficiently and continuously. The transportation of electricity is easy once the transmission lines are functional. They work for years and need no or very less maintenance. The invention of electric power is one of the best inventions which have changed human life drastically. It allows people to do more leisure activities.

In the conventional system to generate electric power, coal is burnt to generate heat which boils the water to produce steam. The steam produced is used to run the turbines which in turn generate the electricity. This is a very old method to generate electricity which produces too much air pollution as a by-product. Due to the burning of coal, carbon monoxide, carbon dioxide, different oxides of sulphur and nitrogen are pumped into the atmosphere which pollutes it badly. As carbon dioxide is the greenhouse gas and its excessive presence in the atmosphere raises the earth’s temperature.

Distribution of electric power is in two types of current, AC and DC. Alternating current is 3 to 4 times more dangerous as compared to direct current. It causes more muscle contraction as it reduces skin resistance by stimulating sweating.

## FAQs on Electric Power

Q.1:  Which type of current is suitable for electric power transmission?

Answer: Electric power is transmitted as alternating current (AC) and not as direct current (DC). AC is cheaper for production therefore power generation plants generate the power in the form of AC. It is easier for distribution as the energy loss is lower than the direct current (DC). Alternating current can easily be step down or up in voltage than DC. Transformers which are used to step down the current are cheaper to build as compared to the DC transformers. Therefore AC is used to distribute the electric power nationally, for long distances.

Q.2: What is the unit of measurement of electric power?

Answer: In general terms, power is the measurement of energy flowing per second. Thus the unit of measurement is joules per second. In the SI system, to measure the electric power a dedicated unit has been assigned and it is the watt (W).

Q.3: Which current is more dangerous to human beings?

Answer: AC is more dangerous than DC. It’s the frequency of the AC which causes the danger to the human body. AC of 60 cycles per second frequency is very harmful to the human body. At this frequency, a person can be electrocuted with a small voltage of 25 V. higher frequencies do not harm even the voltage is high either.

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