ABSTRACT
Power interruption and failure does not promote development. Investors and private organization do not feel secure to establish a business in a country with constant or frequent power failure. Power interruption limits the development of industries, commerce, businesses and seriously effects the economic development of any nation. There are vital jobs or processes that cannot be interrupted due to their importance, for instance surgery operation in hospitals, transfer of money between banks, cashing of money using ATM machines, formatting of computer hard drives, and lots more. These processes do not require power interruption or else there will be lost of lives, time and properties. This project presents the design and implementation of an automatic power changeover system. Automatic power changeover system is a device that automatically starts a generator once there is power outage. It also switches the load from public supply to generator without interruption. The system can as well off the generator when public power is restored. This is achieved using integrated circuits that have timing abilities and electromagnetic relays to effect switching.
Keywords: Switching relay, generator, motor, public power supply, transistor, etc.
TABLE OF CONTENTS
Title page ----------i
Certification page--------ii
Approval page---------iii
Dedication ----------iv
Acknowledgment ---------v
Abstract----------vi
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF THE STUDY-----1
1.2WHAT IS AN AUTOMATIC POWER
CHANGEOVER SYSTEM -------2
1.3 OPERATION OF A TRANSFER SWITCH----3
1.4 AIMS AND OBJECTIVE OF THE PROJECT----4
1.5 SIGNIFICANCE OF THE PROJECT-----6
1.6 THE FEATURES OF AN AUTOMATIC POWER
CHANGEOVER SYSTEM------6
1.7 SCOPE OF PROJECT-------7
1.8 LIMITATION AND CONSTRAINTS ON THE PROJECT-7
1.9 PROJECT REPORT ORGANSATION-----8
CHAPTER TWO
LITERATURE REVIEW------10
2.1 HISTORY OF CHANGEOVER -----10
2.2 OPERATION OF A TRANSFER SWITCH--12
2.3 TYPES OF POWER TRANSFER SWITCH---14
2.3.1 OPEN TRANSITION------14
2.3.2 CLOSED TRANSITION------15
2.3.3 SOFT LOADING-------17
2.3.4 STATIC TRANSFER SWITCH---17
2.3.5 HOME USE OF TRANSFER SWITCH----18
2.4 THE STAND-BY POWER UNIT (GENERATOR)-19
CHAPTER THREE
DESIGN METHODOLOGY AND SYSTEM ANALYSIS-20
3.1 DESIGN METHOD-------20
3.2 DESIGN CONSIDERATION----23
3.3 CONTROL LOGIC UNIT ------24
3.4 CALCULATION OF POWER FOR A THREE
PHASE SYSTEM -------26
3.5 COMPONENT LIST ------27
3.6 DESCRIPTION OF AUTOMATIC POWER
CHANGEOVER SYSTEM -----28
3.7 OTHER COMPONENTS-------31
3.7.1 DIODES--------31
3.7.2 CAPACITOR--------32
3.7.3 RESISTORS--------33
3.7.4 TOGGLE SWITCH-------35
3.7.5 TRANSISTOR--------36
CHAPTER FOUR
SYSTEM IMPLEMENTATION-----41
4.1 HARDWARE IMPLEMENTATION----41
4.2MOUNTING OF THE COMPONENTS---42
CHAPTER FIVE
SYSTEM TESTING AND PACKAGING---44
5.1 SYSTEM TEST--------44
5.2 PERFORMANCE EVALUATION----44
5.3TEST PLAN AND TEST DATA----46
5.4 COMPONENTS TEST------47
CHAPTER SIX
SUMMARY AND CONCLUSION----49
6.1 SUMMARY--------49
6.2 PROBLEMS ENCOUNTERED AND SOLUTION--49
6.3 CONCLUSION -------50
6.4 RECOMMENDATION------51
REFERENCES--------52
LIST OF FIGURES
FIG 3.1: PROJECT ORGANIZATIONS BLOCK DIAGRAM - 8
FIG 3.1: BLOCK DIAGRAM OF THE CIRCUIT ---21
FIG 3.2: CIRCUIT DIAGRAM-----22
FIG 3.9: FOUR TYPES OF DIODES ----32
FIG 3.10: PICTURE OF THE ELECTROLYTIC
CAPACITOR ------33
FIG 3.11: PICTURE OF A FIX RESISTOR USED IN
THE PROJECT ------35
FIG 3.12: A TOGGLE SWITCH -----35
FIG 3.13: LM7805 -------39
FIG 4.1: THE VEROBOARD USED IN THE PROJECT-41
FIG 4.2 FINISHED PROJECT CIRCUIT -----43