The document outlines the electrical power system for the academic year 2020-21, focusing on its components and structure, including generation, transmission, and distribution systems. Key elements such as generating stations, transformers, transmission lines, and distribution networks are detailed, emphasizing the conversion of various energy forms into electrical power. It also includes a diagrammatic representation of a typical transmission and distribution scheme, illustrating the flow of electrical power from generating stations to consumers.

1. Program: Electrical Engineering
Academic Year: 2020-21
Class: SE Semester: III
Course Name: Electrical Power System-I
Course Code: EEC304
Presented By: Mr. Jayesh R. Dhuri
Designation: Assistant Professor
Department: Mechatronics Engineering
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Module No: I Module Title: Basic Structure of Power System
Part: I
Topics to be covered:
Basic Structure of Power System, Generation, Transmission and Distribution, Single Line
diagram of typical AC supply system
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Introduction
The energy is neither be created nor be destroyed but it can
be converted from one form to another. The generation of an
electrical energy is nothing but the conversion of various other
forms of energy into an electrical energy. the various energy
sources which used to generate electrical energy on the large scale
are steam obtained by burning coal, oil, natural gas, water stored in
dams, diesel, oil, nuclear etc.
the electrical power is generated in bulk at the generating
stations which are called power station. the power station are
located too far away from the town and cities where electrical
energy is demanded. hence there exits a large network of a
conductors between the power stations and the consumers. This
network is broadly classified into two parts.
1. Transmission 2. Distribution

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The flow of electrical power from the generating station to
consumer is called an electrical power system.it consists of
following important components.
1. Generating Station
2. Transmission Network
3. Distribution Network
All these important networks are connected with the help
of conductors and various step up and step down
transformers.
Structure of Electrical Power System

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Structure of Electrical Power System
Fig.1: Schematic representation of a typical transmission and distribution scheme

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Structure of Electrical Power System
 a scheme shows generating station which is located too far
away from cities and towns.
 it is generating an electrical power at 11kV.
 with the help of transmission lines and the towers the power is
transmitted at very long distances.
 Design of the transmission lines based on the factors like
transmission voltage levels, constants like resistance, reactance
of the lines, line performance, interference with the neighboring
circuits
The transfer of power from receiving station to the substation is
with the help of conductors called feeders.

7. Components of Distribution
The distribution consists of following important components
1. Substation- transmission lines bring the power upto the substation at a
voltage level of 22kV or 33kV. At the substation the level is reduced to
3.3kV or 6.6kV. Then using feeders the power is given to local distribution
center.
2. Local Distribution Station- it consists of distribution transformers which
step down the voltage level from 3.3kV, 6.6kV to 400V or 230V. Then it is
distributed further using distributors. This is also called distribution
substation.
3. Feeders- These are the conductors which are of large current carrying
capacitor. The feeders connect the substation to the area where power is to
be finally distributed to the consumers.
4. Distributors- these are the conductors use to transfer power from
distribution centre to consumers.
5. Service Mains- These are the small cables between the distributors and
the actual consumer premises.
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8. Components of Distribution
The interconnections of feeders, distributors and service mains is
shown below.
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Fig.3: interconnections of feeders, distributors and service mains

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Single Line Diagram of Electrical
Power System
Fig.2: Line diagram of a typical transmission distribution scheme

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The overall scheme can be divided into four sections
1. Primary Transmission
2. Secondary Transmission
3. Primary Distribution
4. Secondary Distribution
Single Line Diagram of Electrical
Power System

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The single line diagram is nothing but the simplified representation of
power system components with each other, with each component
represented by its symbol.
The standards symbols used for drawing single line diagram of a power
system are shown below.
Symbol used for Drawing Single Line Diagram

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Symbol used for Drawing Single Line Diagram

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Elements of Power System
The power system comprised of various elements such as generators, transformers
Transmission lines, bus bars, circuit breakers, isolators etc.
1. Generator- it is of synchronous type and is driven by turbine thus converting
mechanical Energy into electrical energy
2. Transformer- For stepping up or down the system voltage, power transformers are
used in the substations
3. Transmission Line- The transmission line forms the connecting link between
generating Substation and distribution systems.it carries the power generated by
generating stations and Make it available for distribution through distribution
network.
4. Bus Bars- Bus bars are the common electrical component that connect electrically
number of lines which are operating at the same voltage directly. these bars are
either copper or Aluminum.
5. Circuit Breakers- the circuit breaker are used to open or close a circuit under
normal and faulty conditions.
6. Isolators- in order to disconnect a part of the power system for maintenance and
repair Purpose isolating switches are used.

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For any queries or feedback you can reach me at
(jayeshdhuri@nhitm.ac.in)
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Management