This document provides an overview of electrical power distribution systems. It discusses the key elements of distribution systems including feeders, distributors, and service mains. It also covers the classification of distribution systems based on the nature of current (AC vs DC) and types of construction (overhead vs underground). Finally, it describes different connection schemes for distribution including radial, ring main, and interconnected systems. The document aims to introduce the basic components and design considerations for electrical power distribution to local areas and consumers.

1. WELCOME TO PROFESSIONAL PRACTICE
LAB
SUBMITTED BY UNDER THE GUIDENCE OF
SENGOTECHOLAN S SHRUTHISHREE.S.S
REG NO:410EE16043

2. TOPIC:-
ELECTRICAL POWER
DISTRIBUSTION SYSTEM

3. CONTENTS
Introduction
Elements of distribustion system
Classification of distribustion system
Nature of current
Types of construction
Sheme of connection
Conclusions

4. INTRODUCTION
 “The part of power system which distributes electrical
power for local use is known as DISTRIBUTION
SYSTEM.”

5. ELEMENTS OF DISTRIBUSTION SYSTEM
Distribution line generally consist of
feeders
distributers
service mains .

6. Feeder :-
A feeder is a conductor which connects the substation to the area where power is to
be distributed .
Distributer :-
A distributer is a conductor from which tapings are taken from pole mounted
transformer to the consumer
Service mains :-
A service mains is a generally a small cable which connects the distributer to the
consumer ‘s meter.

7. CLASSIFICATION OF DISTRIBUSTION SYSTEM
Nature of current
AC distribustion system
DC distribustion system
Types of construction
over head system
under ground system
Sheme of connection
radial system
ring main system
inter connected system

8. NATURE OF CURRENT
AC distribution system
1 ) primary distribustion system:-
it is a part of AC distribution system which operates at
voltage higher than general utilization. The most commonly used voltage
are 11kV,33kV,66kV,this carried out by 3phase,3-wire system.
2 )secondary distribustion system:-
it is the part of AC distribution system which includes the
range of voltage at consumer utilizes the electricity, this employs
440/230,3phase,4 wire system

9. DC distribustion system:-
1 )2-wire DC system:-
this consists of two wires one is positive &other is
negative wire. the loads are connected in parallel between the two wires.
this system is not used for transmission purpose due to low efficiency. but
employed for distribustion of power
2 )3-wire DC system:-
this consists of two positive wire & a negative wire
at middle. this makes available two voltage at consumer terminals, voltage
between any positive and neutral and 2voltage between the positive. by this
we can use both low voltage and high voltage loads.

10. TYPES OF CONSTRUCTION
over head system
 Over head lines are less initial cost
 Identification of fault easy
 Public safety is less
 Jointing of conductor is easy
 Interference with communication line is
present
 Voltage drop is high
 Maintained cost of over head line are high
under ground system
 Under ground are more initial cost
 Difficult in fault identification
 Public safety is more
 Change of accident is less
 Interference with communication line is absent
 Voltage drop is less
 Maintained cost of over head line are low

11. SCHEME OF CONNECTION
RADIAL SYSTEM:-
 In this system separate feeder radiate from a single substation and feed the distributors at one
end only
 This is the simple distribution system. but if any fault on the feeder (or)distributors cuts off
supply to the consumer who are on the side of the fault
 This causes voltage fluctuation at consumer’s terminals so this is used for short distance only

12. RING MAIN SYSTEM:-
 In this system primaries of distribution transformer forms a loops, the loop circuit
starts from the substation bus bars, makes a loop through the area served and
return to the substation
 There are less voltage fluctuations at consumer terminals
 This system is more reliable
 If any fault occurs on any section, only the faulty section power will be
interrupted

13. INTERCONNECTED SYSTEM :-
 When the feeder ring is energized by two (or)more than two generating
station (or)substation than it is called interconnected system

14. CONCLUSIONS
There is no fault free system
It is neither practical nor economical to build a fault
free system