Note: The following texts are for the master students who are preparing for the English state
exam. The texts will be followed by reading comprehension and vocabulary exercises. Also will
be added speaking and grammar tasks in the exam.
School of Power Engineering
Text 1
The Main Components of Electric Circuits
The main components of any circuits are devices that produce and utilize electric energy.
They are: 1. Power sources 2. Utilizing loads 3. Connecting conductors.
The most common power sources are electric generators and primary cells. Electric
generators convert chemical energy into electric energy.
Loads include electric heaters, electric motors, incandescent lamps, etc. Motors convert
electric energy into mechanical, incandescent lamps and heaters convert electric energy into light
and heat. Utilizing devices or loads convert electric energy into thermal, mechanical or chemical
energy.
Electric powers is delivered from power sources to loads by electric wires. According to
their material, wires can be aluminium, copper, steel, etc.
In addition to these three main components, electric circuits use different types of
switches, protection devices (relays and fuses), and meters (ammeters, voltmeters, wattmeters,
etc.). The types of electrical circuits associated with electrical power production or power
conversion systems are either resistive, inductive, or capacitive. Most system have some
combination of each of these three circuit types. These circuit elements are also types of loads.
A load is a part of a circuit that converts one type of energy into another type. A resistive load
converts electrical energy into heat energy.
In our discussion of electrical circuits, we will primarily consider alternating-current (ac)
systems as the vast majority of the electrical power which is produced is alternating current.
Direct-current (dc) systems must be studied in terms of electrical power conversation.
Text 2
Transmission Lines
After electricity is produced at power plants it has to get to the customers that use the
electricity. Our cities, towns, states and the entire country are criss-crossed with power lines that
“carry” the electricity.
A power system is an interconnection of electric power stations by high voltage power
transmission lines. Nowadays the electricity is transmitted over long distances and the length of
transmitting power lines varies from area to area.
A wire system is termed a power line in case it has no parallel branches and a power
network in case it has parallel branches.
According to their functions, power lines and networks are subdivided into transmission
and distribution lines.
Transmission lines serve to deliver power form a station to distribution centres.
Distribution lines deliver power from distribution centres to the loads.Lines are also classed into:
1. overhead 2. indoor 3. cable (underground)
Overhead lines comprise line conductors, insulators, and supports. The conductors are
attached to the insulators, and these are attached to the supports. The greater the offered
resistance the higher are the heating losses in the conducting wires. The losses can be reduced
simply by using a step down transformer.
Indoor lines include conductors, cords, and buses. A conductor may comprise one wire or
a combination of bare wire not insulated from one another. They deliver electric current to the
consumer.
As to underground lines, they are suitable for urban areas. Accordingly, they are used in
cities and in the areas of industrial enterprises.
Text 3
Electric Power Consumers and Power System
An electric power consumer is an enterprise utilizing electric power. Its operating
characteristics vary during the hours of day, days and nights, days of week and seasons. All
electric power consumers are divided into groups with common load characteristics. To the first
group belong municipal consumers with a predominant lighting load: dwelling houses, hospitals,
theatres, street lighting system, mines, etc. To the second group belong industrial consumers
with a predominant power load (electric motors): industrial plants, mines, etc. To the third group
belongs transport, for example, electrified railways. The fourth consists of agricultural
consumers, for example, electrotractors.
The operating load conditions of each group are determined by the load graph. The load
graph shows the consumption of power during different periods of day, month and year. On the
load graph the time of the maximum loads and minimum loads is given. Large industrial areas
with cities are supplied from electric networks fed by electric power plants. These plants are
interconnected for operation in parallel and located in different parts of the given area. They
may include some large thermal and hydroelectric power plants.
The sum total of the electric power plants, the networks that interconnect them and the
power utilizing devices of the consumers, is called a power system. All the components of a
power system, are interrelated by the common processes of protection, distribution, and
consumption of both electric and heat power. In a power system, all the parallelly operating
plants take part in carrying the total load of all the consumers supplied by the given system.
Text 4
Nuclear Energy: Solution to Global Climate Change
The issue of global climate has been widely reported on, and was recently covered in the
PBC documentary, “What’s Up With the Weather?” nuclear power plants do not produce carbon
dioxide emissions, which are a major contributor to the greenhouse effect and global climate
change. In fact, nuclear energy releases no emissions of any kind, so they also do not contribute
to local air pollution problems. The US Representative to UN Organizations in Vienna,
Ambassador John B. Rich III, has declared that “only nuclear energy can help meet the world’s
energy needs without threatening the environment”. Worldwide, reliance on nuclear has reduced
greenhouse gas emissions by almost metric tons annually.
The herring: the “problem” of nuclear waste. The entire nuclear power industry generates
approximately 2.000 tons of solid waste annually in the United States. All technical and safely
issues have been resolved in creation of high-level waste repository in the US; politics are the
only reason we do not have one. In comparison, coal fired power produced 100.000.000 tons of
ash and sludge annually, and this ash is laced with poisons such as mercury and nitric oxide.
Industry generates 38.000.000 tons if hazardous waste, and the kind they make will be with us
forever, not decaying away, this waste does not receive nearly the care and attention in disposal
that radioactive waste does. This is not to say that radioactive waste is more dangerous; it is not.
We should be probably more careful with other industrial wastes.
Text 5
Power Engineering
Power engineering is a science which studies all kinds of energy. It is a very young
science and it is applied in very branch of industry. Our industrial progress is based on power,
power for our machines, industrial plants, heating and lighting systems transport and
communication. Indeed, there is hardly a sphere of our life where power is not required. We may
trace the rise of civilization by man’s ability to generate power.
Power engineering comprises different sciences and branches of sciences such as:
mathematics, machine details, strength of materials, electrical engineering, hydrolics, heat
transfer, electrical units, gas and steam turbines, atomic reactors, solar installations and many
others.
Power supply is one of the major criteria of a country industrial might. Without an ample
power supply, no branch of national economy can develop rapidly or at all effectively.
Industrial process depends on power. For centuries coal, oil and water were its main
sources. In the 19th century they were used to produce steam. In the first half of the 20th centuryelectricity. Our time is the age of automatic power. A new fuel and a new source of power is put
to the service of man.
Today we obtain power from many sources: one of them is coal, oil, natural gas, to
produce the best that operates internal and external combustion engines. The other source is
falling water in our hydro-electric power stations, where water turbines operate electric
generators, the next is nuclear reactor which produces heat by means of atomic fission. We also
use the energy of tides, subterranean heat and solar energy to produce electricity.
Power engineering includes such forms of energy as: solar, atomic, thermal, electric
energy from combustion of coal oil, shale and gas, steam power, wind etc.
Text 6
Energy Source
The sources from which energy can be obtained to provide heat, light, and power. Energy
sources have progressed from human and animal power to fossil fuels and radioactive elements,
and water, wind, and solar power. Industrial society was based on the substitution of fossil fuels
for human and animal power. Future generations will have to increasingly use solar energy and
nuclear power as the finite reserves of fossil fuels become exhausted. The principal fossil fuels
are coal, lignite, petroleum, and natural gas – all of which were formed millions of years
ago.
Fossil fuels which have potential for future use are oil shale and tar sands.
Oil shale deposits have been found in many areas of the United States, but the only deposits of
sufficient potential oil content considered as near-them potential resources are those of the Green
River Formation in Colorado., Wyoming, and Utah.
Tar sands represent the largest known world supply of liquid hydrocarbons. Extensive
resources are located throughout the world, but primarily in the Western Hemisphere. The bestknown deposit is the Athabasca tar sands in northeastern Alberta, Canada.
Nonfuel sources of energy include wastes, water, wind, geothermal deposits, biomass, and solar
heat. At the present time the nonfuel sources contribute very little energy, but as the fossil fuels
become depleted, the nonfuel sources and fission and fusion sources will become of greater
importance since they are renewable. Nuclear power based on the fission of uranium, thorium,
and plutonium, and fusion power based on the forcing together of the nuclei of two light atoms,
such as deuterium, tritium, or helium 3, could become principal sources of energy in the 21st
century.
All sources of energy put together is energy locked up in nuclei of atoms of matter itself.
It has been known for at least a century. It is called nuclear energy.
Many atomic power plants for producing electric energy were built in many countries of the
world. There are great possibilities of using nuclear energy for world. A number of countries are
working at the development and construction of various kinds of locomotive, airplanes and other
means of transport. Many atomic powered ships have been already built. Nuclear energy is and
will be used in medicine, and in many spheres of life where the atom may find useful
application.
Text 7
Power Plants
Electric power is generated at electric power plants. The main unit of an electric power
plant comprises a prime mover and the generator which it rotates.
In order to actuate the prime mover energy is required. Many different sources of energy
are in use nowadays. To these sources belong heat obtained by burning fuels, pressure due to the
flow prime mover, power plants are divided into groups.
Thermal, hydraulic (water/power) and wind plants are classed as:

Steam turbine plants, where steam turbines serve as prime movers. The main generating units at
steam turbine plants belong to the modern, high-capacity class of power plants.

Steam engine plants, in which the prime mover is a piston-type steam engine. Nowadays no large
generating plants of industrial importance are constructed with such prime movers. They are
used only for local power supply.

Diesel-engine plants; in them diesel internal combustion engines are installed. These plants are
also of small capacity, they are employed for local power supply.

Hydroelectric power plants employ water turbines as prime movers. Therefore they are called
hydroturbine plants. Their main generating units is the hydrogenerator.

Modern wind-electric power plants utilize various turbines; these plants as well as the small
capacity hydroelectric power plants are widely used in agriculture.

Hydroelectric stations deliver power from great rivers, but still about 80 percent of the required
electric power is produced in thermal, electrical plants. These plants burn coal, gas, peat or shale
to make steam.
Text 8
An Electric Motor
An electric motor is a device using electrical energy to produce mechanical energy.
Electric motors are everywhere! In your house, almost every mechanical movement is caused by
an AC (alternating current) or DC (direct current) electric motor.
In an electric motor an electric current and magnetic field produce a turning
movement. This can drive all sorts of machines, from wrist- watches to trains.
An electric current running through a wire produces a magnetic field around the
wire. If an electric current flows around a loop of wire with a bar of iron through it, the iron
becomes magnetized.
If you put two magnets close together, like poles-for example, two north poles –
repel each other, and unlike poles attract each other.
In a simple electric motor, a piece of iron with loops of wire round it, called an
armature, is placed between the north and south poles of a stationary magnet, known as the field
magnet when electricity flows around the armature wire, the iron becomes an electromagnet.
The attraction and repulsion between the poles of this armature magnet and the
poles of the field magnet make the armature turn. As a result, its north pole is close to the south
pole of the field magnet. Then the current is reserved so the north pole of the armature magnet
becomes the south pole. Once again, the attraction and repulsion between it and the field magnet
make it turn. The armature continues turning as long as the direction of the current, and therefore
its magnetic poles, keeps being reversed.
To reverse the direction of the current, the ends of the armature wire are connected
to different halves of a split ring called a commutator. Current flows to and from the commutator
through small carbon blocks called brushes. As the armature turns, first one half of the
commutator comes into contact with the brush delivering the current, and then the other, so the
direction of the current keeps being reversed.
Text 9
Portable Generator
A portable generator can provide electricity to power lights and other appliances no
matter how far you are from the mains. It works by turning the movement of a piston into
electrical energy.
Although most electricity comes from power stations, power can also be generated
by far smaller means. Nowadays, electricity generators can be small enough to hold in the hand.
Portable generators are made up of two main parts: an engine, which powers the equipment, and
an alternator, which converts motion into electricity.
The engine which runs on petrol, is started by pulling a cord. This creates a spark
inside which ignites the fuel mixture.
In a typical four-stroke engine, when the piston descends, the air inlet valve opens and a mixture
of air and petrol is sucked in through a carburetor.
The valve closes, the piston rises on the compression stroke and a spark within the
upper chamber ignites the mixture. This mini- explosion pushes the piston back down, and as it
rises again the fumes formed by the ignition are forced out through the exhaust valve.
This cycle is repeated many times per second. The moving piston makes the
crankshaft rotate at great speed.
The crankshaft extends directly to an alternator, which consists of two main sets of
windings-coils of insulated copper wire wound closely around an iron core. One set, called stator
windings, is in a fixed position and shaped like a broad ring. Other set, the armature windings, is
wound on the rotor which is fixed to the rotating crankshaft. The rotor makes about 3.000
revolutions per minute.
Text 10
Transformers
Faraday’s experiments of August 29, 1831, gave us the principle of the electric
transformer, without which the later discoveries of that fateful year could have little real practical
application. For to convey electric current over long distances, say to supply a town, or feed an
electric railway, it is necessary to generate it at a very high voltage, or force. By means of
transformers based on Faraday’s induction coil discovery, it is simple for a current from the grid
or direct from a power-station of say 132.000 volts to be stepped down for the electric train to
600 volts and for household use to 240 volts. Smaller transformers in individual prices of
electrical equipment, say a shaver or radio, may step the current down still further for special
purposes.
Similarly, currents may be stepped up in voltage, if required, by the same device. The
procedure is quite simple. The current is fed into the transformer across the primary, of input
coil, which corresponds to Faraday’s right-hand coil on his induction ring. The resultant induced
current is taken from the secondary, of output coil, which corresponds to Faraday’s left-hand
coil, the voltage will be stepped down.
So the two related discoveries of 1831 provided not only the means of making electricity
easily and cheaply, on as large a scale as required, without any cumbersome batteries, but also
the way of using it in a safe and practical way.