Design And Construction Of A Single Phase Automatic Transfer Switch With Embedded Auto Generator Shutdown And Alarm System

ABSTRACT

As technological advancement has been on the increase in our society many have fallen in love with technology and world want to have a feel in virtually to everything they do.

An Automatic Changeover Switch switches off the generator and automatically changes over to PHCN. An Automatic Changeover Switch will automatically switch off your generator and change over to MAIN (Public power supply) on resumption.

A design has been made in combination of electrical and electronics to change over from one power sources to the other automatically, trip off generator through a relay and blow an alarm at power resumption.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

CHAPTER ONE

• INTRODUCTION
• BACKGROUND OF THE PROJECT
• PROBLEM STATEMENT
• AIM AND OBJECTIVE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• APPLICATION OF THE PROJECT
• PURPOSE OF THE PROJECT
• PROBLEMS OF THE PROJECT
• SCOPE AND LIMITATION OF THE STUDY
• DEFINITION OF TERMS

CHAPTER TWO

LITERATURE REVIEW

• REVIEW OF THE STUDY
• MANUAL CHANGE-OVER SWITCH
• AUTOMATIC CHANGE-OVER SWITCH
• THE SYSTEM COMPONENT ANALYSIS
• THEORIES AND MODULES RELEVANT TO THE DESIGN
• REVIEW OF RELATED STUDIES
• REVIEW OF FUNDAMENTAL CONCEPTS
• REASONS FOR AUTOMATIC CHANGE-OVER SWITCH
• PROBLEMS OF AUTOMATIC CHANGE-OVER SWITCH

CHAPTER THREE

METHODOLOGY

• SYSTEM DESIGN
• SYSTEM BLOCK
• CIRCUIT DIAGRAM
• CIRCUIT DESCRIPTIONS

CHAPTER FOUR

4.0      IMPLEMENTATION TESTING AND RESULTS

• TESTING
• EXPECTED AND ACTUAL TEST RESULTS
• PACKAGING OF THE SYSTEM

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION

REFERENCES

CHAPTER ONE

1.0                                                     INTRODUCTION

1.1                                       BACKGROUND OF THE STUDY

This project is on the design and co of automatic change over and how it can be used to change from one power sources to the other automatically. The design comprises some arrangement that senses the power failure form either of the power sources and drives the electro mechanical switching device (relay) that is capable of changing two poles (live and neutral) to give out light or be on standby to generator side.

Power instability or outage in general does not promote development in the public and private sector. The investors do not feel secure to come into a country with constant or frequent power failure. These limit the development of industries. In addition, there are processes that cannot be interrupted because of their importance for instance, surgery operation in hospitals, transfer of money between banks and lots more. Power instability and outage in developing countries (Nigeria) creates a need for alternative sources of power to backup the mains supply.

Automatic changeover switches find a wide application scope wherever the reliability of electrical supply from the utilities is low and it is used in lighting/motor circuits wherever continuity of supply is necessary, for switching to an alternative source from main supply and vice versa.

Electronic components such as relay transformer diodes were used thereby making the project less expensive for the implementation of the project and commercial application.

Moreover, the cost suitability and availability of the required components for the project circuitry were some of the major factors considered by the designer

1.2                                                  PROBLEM STATEMENT

Power failure or outage in a country, state or city is highly detrimental to development in public and private industries. The insecurity associated with constant or frequent power failure or outage brings about limitation to power  consistent investments, thus hampering the development of industries and multinational ventures. Processes like carrying out surgical operations in hospitals, laboratories which require constant power supply for research, money transactions  between banks and more require constant use of uninterrupted power. In other to solve this problem, an automatic changeover switch was invented. This research covers the design and construction of a single phase digital automatic power changeover. It has the capacity to automatically switch power from  national grid to generator and vice versa, once there is power failure in any of the two power supplies and at the same time has the capacity of shutting down a generator set once the mains grid is been restored.

1.3                                                    AIM/OBJECTIVES

The main aim of the study is to build a single phase automatic transfer switch with embedded auto generator shutdown and alarm system. The objectives of the study are:

1. To build the system prototype.
2. To design a circuit that will automatically change over from main power supply (PHCN) to power generating set and vice versa.

• To electromechanically control OFF a generator set with the help of relay.

1. To indicate power supply through an alarm

1.4                                         SIGNIFICANCE OF THE PROJECT

• It minimizes damages to lives/equipment since it has its own monitoring system and its switching requires no human contact with the switch, thus eliminating human error.
• It reduces its change over timing to the minimum due to its fast response to power outage.
• It maintains high quality of service through its fast and prompt response.
• Moreover, the size and captivity of the unit will depend upon the load for which it will be used. The unit is also portable, easy, convenient and safe to install.
• Genset is put off automatically when main power resumes.
• Fuel is saved due to auto stop facility.

1.5                                              PURPOSE OF THE PROJECT

The main purpose of this work is to provide a means of having uninterruptible power supply in our home, office, workshops or industries.

1.5                                         PROBLEMS OF THE PROJECT

In every home, office or industries, automatic power changeover  plays a vital role, that is, It provides a means of switching from utility AC mains to generator in the case of power failure; This project has been improved on the existing types of electromechanical device that has being in use over the years.

In the course of designing this project, different kinds of problem was notice such as:

• Difficulty in troubleshooting with circuit without the circuit diagram
• Difficulty in connecting the output without short-circuiting, until a multiplexing circuit was gotten.
• Difficult in wiring because of the strong wiring the project required.

1.6                              SCOPE AND LIMITATION OF THE STUDY

This work covers only a one phase automatic changeover which can only be used for providing a means of switching from one phase of AC mains to another in the case of failure in public utility. Switching from the mains supply to generator set, and generator trip OFF mechanism is carried out via a relay and the power resumption alarm system is based on the monostable configuration. It is limited to

   Phase – one phase

   Capacity – single Phase

   Input Volt – 220v

1.7                                         APPLICATIONS OF THE PROJECT

1. This circuit can be used as a home lighting system with few modifications.
2. It can be used to drive other DC loads like a DC motor of any electronic appliance or other toy applications.

This device is used in the following places:

3. home,
4. office,
5. worship places
6. workshops or industries

1.8                                             DEFINITION OF TERMS

CHANGEOVER: Generally, a changeover switch is a system which could be operated manually or automatically , that changes one source of power supply to another source in case of power failure from either of the two sources.

RELAY: relay is one of the major components used in this work which is an electrical device, typically incorporating an electromagnet, which is activated by a current or signal in one circuit to open or close another circuit.

POWER FLUCTUATIONS: is a periodic dip or spikes in the electrical current of any given circuit.

POWER FAILURE: is a short- or long-term loss of the electric power to an area.       

1.9                                                        METHODOLOGY

To achieve the aim and objectives of this work, the following are the steps involved:

1. Study of the previous work on the project so as to improve it efficiency.
2. Draw a block diagram.

• Test for continuity of components and devices,

1. Design and calculation for the changeover was carried out.
2. Studying of various component used in circuit.
3. Construct a digital changeover circuit.

• Finally, the whole device was cased and final test was carried out.