ABSTRACT
Auto Phase Selector (ASP) system is
used to ensure continuous supply to load in case mains supply is not healthy.
This unit is very useful at the site at which main supply is irregular. It may
be sometimes very high or sometimes very low voltage. The frequent
failure/fluctuations of power affect life of power plant and battery. The
objective of the APS is to ensure that there is continued commercial power
supplied to the site at all times so as to ensure that the Base Transceiver
Station BTS) runs on commercial power until all available phases are either out
of electrical tolerance or completely off. This is a microcontroller based unit
three and it is used with three phase electrical supply.
Whenever the supply of one or two
phases of a three phase electrical line goes off, the ASP system automatically
distribute the electrical supply from the active phase to the failed phases.
These ensure continues power supply through all the three phases even if only
one phase is active.
TABLE OF CONTENT
TITLE
PAGE
LETTER
OF SUBMISSION
CERTIFICATION
ACKNOWLEDGMENT
DEDICATION
TABLE
OF CONTENT
ABSTRACT
CHAPTER ONE
1.0
Introduction
11 Brief Description
1.2
Objectives of the Project
1.3
Significant of the Project
1.4
Project Hypothesis
CHAPTER TWO
2.0
Literature review
2.1
Functions of automatic switch
2.2
Different type of transfer switch
2.3
Conditioning Element
2.3.1
Resistors
2.3.2
Capacitors
2.3.2.1
Capacitors Makings
2.4
Diodes
2.4.1
Types of Diodes
2.5
Bi-Polar Junction Transistors
2.6
Discrete Components
2.6.1
The Electromagnetic Relay
2.6.
Primary Function of a Relay
2.6.2
The Contactor
2.6.3
Indicator Lamp
2.6.4
Selector Switch
2.6.5
Choice of Cable
2.6.5b
Determination of Cable size Used
CHAPTER THREE
3.0 The MCU
3.1
Phase Detector
3.1
Phase Detector Circuit Diagram
3.2
Voltage Scalier
3.2
Voltage Scalier Circuit Diagram
3.3
Micro Controller Unit
3.4
Output Stage
3.5
Building an AC to AC Converter
3.6
The Relay
3.6.lb
Problems with Relays
3.6.2
The Crystal
3.6.2b
Function of a Crystal 25
3.6.3
The Microcontroller Regulator IC (KLM
7805)
3.6.4
The Liquid Crystal Display (LCD)
3.6.5
The Microcontroller (PICs)
3.6.5
The Microcontroller (P Diagrams
3.6.5b
Advantages of the PlC Microcontroller
3.7
Programming of a PlC
3.8
Word size of the PlC
3.9
Description of the Microcontroller (P
3.9b Features of the PIC16FS76A
3.Sc Design Specification of the P1C15F876A
CHAPTER FOUR
4.0
Constructional Stage
4.1
Writing of the Source Code
4.2
Assembling of the Code
4.3
Burning of the Code in the MCU Chip
4.4
First test
4.4
Testing of the Circuit on a Breadboard
4.5
Soldering of the Final Project on a
veroboard
4.6
Casing of the Circuit
4.7
Advantage of a DPS
4.8
Components Used
4.9
Other Components Used
CHAPTER FIVE
5.0
Result and Conclusion
Testing
Recommendation
References
CHAPTER
ONE
1.0
INTRODUCTION
Generation and availability of
constant electricity of the right power has lead to the establishment and smooth
running of industries, most especially in the advanced countries. At our
various homes, electricity has made possible the use of devices like cookers,
microwave-ovum, refrigerators, computers and so on. Unfortunately, most
developing countries are suffering from high rate of power failure in one or
two of the three phases, low voltage or high voltage supply.
In the early period of development of
technology transfer switches were operated only manually by an operator.
This project is to improve availability
of power supply since interrupted supply is highly required to operate
electrical or electronics devices such as in the hospital equipments, to save
the lives of patients under surgical operations. Industries also, as mentioned
earlier, require continuous power supply in order to keep production operations
in continuous form and to save millions of naira that could be lost as a result
of power failure. These requirements have hastened the demand for the
designing, construction and introduction of Digital Phase Selector which is an
electrical/electronic device that switch to the loads, one phase out of the
three phases automatically. It can detect and compare the three phases and then
select the best (base on voltage measurement) so that power can always be
available (provided that at least one of the phases is having power supply).
Hence, this project is concerned with the design and construction of Digital
Phase Selector, DPS for short.
A DSP can be defined as an
electrical/electronic device used to switch electrical power supply into loads
automatically and to compare and select the best phase out of the three phases.
It is used to supply constant power to loads even if there is power failure on
any one or two of the phases.
Moreover, the motive behind this
report is to provide a comprehensive and concise coverage of the components
used, and fundamentally gives a technical recount of the design and
construction process involved. The project is an event-driven system, whose
success revolves around a class of device: micro controller unit (Mcli).
Detection is effected when sine wave mains voltage on each of the phases is
converted into direct current, scaled down into the MCU which does the
comparison and selection. It consist of eight stages which are power pack,
phase detection, voltage scaller, ADC, comparator/selector, lcd and beeper
drivers and output stages. Thus, some of the stages are taken care of by
software codes {using basic language} which were burnt into a PlC
microcontroller unit. The software approach considerably reduces the number of
components, cost of production, project size. But on the other hand, it
consumes time i.e. time for code writing and code debugging.
1.1
BRIEF DESCRIPTION
Back-up power could be defined as a
system which takes care of the downtime for changing from one phase line or
power supply to another. These require a Microcontroller (PIC16FS76A) which
acts as the brain of the circuit) the microcontroller IC KLM 7805 etc. Some are
manually started and stopped while others start and stop automatically. Based
on this project the back-up electrical system is taken care of by the automatic
transfer switch which is designed to switch automatically to the best preferred
phase whenever there is voltage drop or power failure from PHCN or other
sources.
This project is designed for both the
three phases and single phase auto-start generator; it also designed for
reliability with low maintenance.
1.2 AIMS AND OBJECTIVES
• The main objective of this project which
is part of an advancement in technology is to make life convenient and
conducive.
• To apply the knowledge acquired in the
study of computer engineering in the designing of DPS.
• To appraise a good proportion of the
overall knowledge gained through a period of two academic sessions in a signed
project work.
• To enhance the understanding and
functions of various electronic components and the combination of their
characteristic to solve specific problems.
• To enhance the scope of the knowledge of
the designer in the area of both analogue and digital electronics.
• To afford the learning of electronic
software packages like express PCB for drawing circuit layout, proteus for
circuit design and simulation and lastly, Micro basic pro compiler for writing
codes, debugging
1.3
SIGNIFICANCE OF THE PROJECT
• The importance of the project can be
viewed from the benefits enjoyed practically and academically.
• It tends to find answer to psychological
reaction of electrical power consumer about electrical power failure.
• The project will help n specifying the
areas of education for engineering students and engineers.
• The project will have great industries
positively by increasing and improving productivity.
• Academically, the project will provide
more insight into phase selector system and engineers and engineering students
will broaden their knowledge.
1.4
PROJECT HYPOTHESIS
This project is Instant automatic
phase change over when any phase fails and it can get electric supply in all
the 3-phase lines (provided any one phase is available) because it need not
monitor for switching back and will surely yield the productivities in
industries. It will also save time during production if the design and the
testing is successful.
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