Monitoring and Control of 3-Tier Power Supply

Monitoring and Control of 3-Tier Power Supply.

ABSTRACT

A reliable electricity supply is essential for development. As a result, demand for electricity has continued to increase globally, occasioned by the fact that electricity is highly portable and can be transformed from one form to another to meet needs.

In Nigeria and most developing countries, electricity supply from the public utility is not only insufficient but highly erratic. The effect of this is adverse on critical and sensitive infrastructure that depends on an uninterrupted power supply.

Hence, many domestic, industrial, and commercial consumers are compelled to acquire one form of alternative source of power supply or another.

With this, however, when different power schemes are interconnected, there arises the challenge of switching between the power sources not only smoothly, but in a manner that optimizes their use.

Solving these challenges forms the focus of this work. This design monitors three independent power sources: Utility Grid of Power Holding Company of Nigeria (PHCN), solar, and generator and engages them following preset conditions in a microcontroller.

A software program in assembly language drives the microcontroller.

Preference is given to the PHCN line, but in the event of failure or abnormal conditions in the PHCN line, the system will affect a changeover automatically to the solar source through contactors, provided the output of the solar source is acceptable, else the system will initiate the starting of the generator and transfer of load to same.

This system finds application wherever there is an unreliable power supply and interconnected power schemes.

TABLE OF CONTENTS

TITLE PAGE i
APPROVAL PAGE ii
CERTIFICATION iii
DECLARATION iv
DEDICATION v
ACKNOWLEDGEMENT vi
ABSTRACT vii
TABLE OF CONTENT viii

CHAPTER ONE INTRODUCTION 1

1.0 Project background 1
1.1 Statement of problem 2
1.2 Project objectives 2
1.3 Significance of project 3

CHAPTER TWO LITERATURE REVIEW 4

2.0 Electricity in Nigeria 4
2.0.1 Nigeria’s Electricity Sector in Retrospect 5
2.0.2 Nigeria’s Power Sector Reform 6
2.0.3 Electricity Power Sector after Privatisation 8
2.0.4 Electricity Production and Consumption in Nigeria 11
2.1 Electricity from Solar 13
2.1.0 Components of a PV system 14
2.1.1 Design Considerations 20
2.1.2 Energy from the PV module 21
2.2 Use of Generators 22
2.3 Transfer Switches 23
2.3.0 Types of Transfer Switches 24
2.3.1 Applications of Closed Transition Transfer Switch (CTTS) 25
2.4 Uninterruptible Power Supplies (UPS) 26
2.5 Microcontroller and Embedded systems 26
2.5.0 The 89C52 Microcontroller 27
2.6 Comparator 38
2.6.0 Comparator parameters 39
2.6.1 Comparator applications 43
2.7 Relay 45
2.8 Contactor 46
2.8.0 Contactor Operation 48
2.9 Step down transformer 49

CHAPTER THREE METHODOLOGY 51

3.0 Introduction 51
3.1 Design Stages: Circuit Simulation 55
3.2 Voltage Monitoring 57
3.2.0 Step down transformer 57
3.2.1 Rectifying circuit 58
3.2.2 Filtering and smoothing circuit 60
3.2.3 Voltage detection circuit 62
3.3 Realizing the Software 64
3.4 Switching circuit 66

CHAPTER FOUR SYSTEM DESIGN AND IMPLEMENTATION 68

4.0 Selection Of Components 68
4.1 Contactor Design 68
4.2 Voltage Monitoring Circuit Design 69
4.3 Circuit Breaker Design 72
4.4 Relay Design 73
4.5 Pilot and Indication Lamps 73
4.6 Conductor Design 73
4.7 Testing and results 74
4.8 Cost analysis 76

CHAPTER FIVE CONCLUSION AND RECOMMENDATION 78

5.0 Conclusion 78
5.1 Recommendation 78
REFERENCES 79

INTRODUCTION

1.0 Project Background

Electricity is of enormous importance to society today. It is indispensable to social and economic development. Modern industrial systems depend on a regular supply of electricity.

Quality of life and standard of living today depend much on electricity. People need energy in one form or the other (heat, light, sound, etc) and electricity is most convenient in that it can be converted with ease from one form to another.

However, in many developing nations steady availability of electricity is yet to be realized.

In Nigeria, for instance, the supply of electricity from the public utility (PHCN) is unreliable, marked by incessant outages, and therefore inadequate for any meaningful advancement in industrial, commercial, and domestic activities.

Generators are commonly used in Nigeria but the cost of running diesel or other fuel for running generators all the time is not feasible for both home and business concerns.

Renewable sources like solar are also used but so far there is yet room for improvement before solar power can be utilized without some form of backup.

Thus, a multi-tier power supply, a system of more than one power source, has gradually become the norm in our society.

This project “Monitoring and Control of 3-tier Power Supply” provides a way of monitoring and switching between three different power sources in order to optimize their use.

REFERENCES

Bing Tian et al. “400 V/1000 kVA Hybrid Automatic Transfer Switch”, IEEE Transactions Ind. Electronics Vol. 60 , No. 12, pp. 5422-5435. 2013.

Oparaku, O.U. “Photovoltaic systems for distributed power supplies in Nigeria”, Renewable Energy, pp 31-40. 2002.

Energy Sector Management Assistance Program. Nigeria: Expanding Access to Rural Infrastructure Issues and Options for Rural Electrification, Water Supply, and Telecommunications. The International Bank for Reconstruction and Development, The World Bank, 2005.

Nigerian Electricity Market, retrieved from www.nipptransactions.com/background/electricity-market, March
2014.

Electricity supply and demand – National Bureau of Statistics, retrieved from www.nigerianstat.gov.ng, March 2014.
About Enugu Electricity Distribution Company retrieved from http://www.enugudisco.com, February 2014