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ABSTRACT
The project is design to provide interrupted ac mains supply i.e 230v to a single phase load. This is achieved by automatic changeover of the load from the missing phase to the next available phase in a 3 phase system. It is often noticed that power interruption in distribution system is about 70% for single phase fault while other two phase are in normal condition. Thus in any commercial or domestic power supply system where 3 phase is available. It is advisable to have an automatic phase selector system for interrupted power to critical loads in the event of missing phase. In this system auto selection is achieved by using a set of relays and microcontroller interconnected in such a way that if one of the dc relay feeding to the ac relay load remains energized always. When there is a phase failure condition, the circuit switches automatically to an available phase that is on, continually supplying to a single phase output.
TABLE OF CONTENTS
COVER PAGE…………………….. Error! Bookmark not defined.
CERTIFICATION ii
DEDICATION iii
DECLARATION iv
STATEMENT 1 v
ACKNOWLEDGEMENT vi
ABSTRACT vii
TABLE OF CONTENTS viii
CHAPTER ONE 1
INTRODUCTION 1
1.1 BACKGROUND OF STUDY 1
1.2 OBJECTIVES OF STUDY 3
1.3 SIGNIFICANCE OF STUDY 4
1.4 SCOPE OF STUDY 5
1.5 LIMITATION OF STUDY 5
CHAPTER TWO 6
2.0 LITERATURE REVIEW 6
2.1 REVIEW OF PAST WORKS 7
2.2 PARTS AND COMPONENT REVIEW 8
CHAPTER THREE 21
METHODOLOGY 21
3.1 THE BLOCK DIAGRAM OF THE AUTOMATIC PHASE SELECTOR 21
3.2 THE HARDWARE CONSTRUCTION STAGE BY STAGE PROCESS 23
3.2.1 FOR THE POWER SUPPLY 23
3.2.2 FOR THE VOLTAGE SENSING UNIT 24
3.2.3 FOR THE CONTROLLER UNIT 26
3.2.4 FOR THE RELAY DRIVER UNIT 26
3.2.5 FOR THE RELAY 27
3.2.6 LCD PHASE STATUS DISPLAY UNIT 28
3.3 THE COMPLETE CIRCUIT OPERATION 28
3.3.1 THE POWER SUPPLY UNIT 29
3.3.2 THE AC SENSING UNIT 30
3.3.3 THE CONTROLLER, RELAY DRIVER AND DISPLAY UNIT 31
3.4 LIST OF COMPONENT USED 32
3.5 SOME SYSTEM DESIGN ANALYSIS 33
CHAPTER FOUR 37
4.0 CIRCUIT OPERATION AND TESTING 37
4.1 THE REGULATED POWER SUPPLY TESTING AND OUTPUT 37
4.1.1 TRANSFORMER + MAIN SUPPLY 38
4.1.1 TRANSFORMER MAIN SUPPLY. 39
4.1.2 TRANSFORMER + RECTIFIER 41
4.1.3 TRANSFORMER + SMOOTHING 42
4.1.4 TRANSFORMER + RECTIFIER + SMOOTH + REGULATOR 44
4.1 HOW IT WORKS 45
4.2 RESULTS AND DISCUSSION 46
4.3 RESULT TABLES 46
CHAPTER FIVE 49
5.0 CONCLUSION 49
5.1 RECOMMENDATIONS 50
REFERENCES 53
APPENDIX 1 54
APPENDIX 2……………………………………………………………………..62
CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF STUDY
Power instability and phase failure has posed serious threat to the economy of the nation. In most developing countries, the power sector has been trouble by high technical lack of losses, a lack of cost recovery pricing, poor maintenance, low equipment reliability, high staff levels, productivity, corruption, a crippling non payments problem and mounting debt. These factors have resulted in the commercial unsustainability of many developing countries sectors, which unable to attract the needed private investment Kuale and I Sado (2006). The lack of reliable power and other infrastructure has had a notably adverse impact on the industrial growth and individual development and these has contributed to perpetuating poverty Bacon (1995). That is to say, where there is erratic power supply there is less development: one of the factors that boost the economy is the availability of steady and stable power supply.
However, most companies, industrial, commercial and even domestics are dependent on public power supply which have erratic power supply such as phase failure, phase imbalances or total power failures due to technical reasons which can be that power lines are over loaded resulting to a trip of power by the switch gears, fuses in the feeders are broken, or load shading process undertaken by the distribution company.
In a case where a single phase public utility prepaid meter is operated with a single phase power supply unit and there is phase failure from the public utility power supply, the prepaid meter will stop reading. At this point if the phase is not manually changed power will be out for user, that is to say someone needs to be present always to make the changes at any point in time. But to overcome these protocols automatic phase selector system needs to be used.
The need to meet the power requirements of the people lead to the construction of automatic phase selector system. Although the government has made efforts to stabilize power generation in the country, 1998 when the national council on privatization (NCP) empowered a 23 member’s electrical sector reform implementation committee (ERIC) to develop guidelines to promote the policy goals of the total liberalization, competition and private sector lead growth of electricity sector, this is to ensure that Nigeria has electrical power industry (EPI) that can meet the needs of its citizens in the 21st century Asubiojo (2007), irrespective of these efforts, the power is still suffering from instability. Power generated and distributed has its own challenges which could be fault on the line, short circuit, phase failure etc, denying the people access to the available power. This has led to the need for automatic phase selector system. The automatic phase selector is a system that can select the next available phase normal voltage. For a preferred phase, a manual selection is on the system.
The system consists of three main parts namely:
- The Transformer
- Voltage Regulator and
- The Electrical Switching Device (Relay)
Some other important components are capacitor, microcontroller, (Atmega 3288, diodes, resistors, LCD Display and circuit board. The DC relays sends the different phase voltage to AC relays, then to the load.
1.2 OBJECTIVES OF STUDY
The main aim of the project is to present an automatic phase switching for 220V alternating current. Other aim includes:
- To develop a simple low cost device aimed at easing the prevalent burden faced by delicate offices, parastatals and institutions who need very low cost but constant power supply.
- In a situation there is power on the distribution line and a phase trip off due over loading or other reason. The automatic phase changer therefore erases a setback that may occur as a result power outage.
- To stimulate the interest of upcoming students to take up research not only in their field of study “Electrical/Electronics Engineering” but also extend their arms to other discipline, thus enhancing the versatile Electrical/Electronics Engineering.
- To create awareness that will stimulate the interest of fellow students who intend to take up research topic on automatic switch of any type.
1.3 SIGNIFICANCE OF STUDY
The significance of the project cannot be overemphasized, because the hazard associated with electricity is very high. Thus the study signifies that:
- The risk involved in the manual control or switching has been totally eliminated by the automatic control.
- The application of the project work would reduce manual labour and cost of maintenance of manual switching devices.
- Accident ca n occurs as a result of manual control which can be eliminated.
- The application of the project work will definitely remove stress and down time in industries were constant single phase is required.
1.4 SCOPE OF STUDY
The scope of the project covers the application, which is either domestic or industrial purpose, its features and advantages: also the component used for the constructions. It also covers the importance or the need for the project work.
1.5 LIMITATION OF STUDY
Without reliable and comprehensive data, this project was faced with lack of proper information need for analysis and comparison. Again due to the problem of mobility and finance: this project suffered a setback in acquiring the equipment and facility needed. It was also an uphill task to get all the necessary component needed for the circuit construction.
Complete Material Cost #3,000
Order for Complete Material now