Design And Implementation Of Automatic Transfer Switch With Power Sensor And Shutdown Timer

ABSTRACT

Automatic transfers switch a device for use with a stand-alone generator, for supplying emergency power to a residence or small business. The automatic transfer switch apparatus is configured to sense a utility line failure, start up and stabilize the generator, and switch over the household circuits from the utility to the generator, and switch back when the utility recovers. A load-shedding feature is provided for shedding and restoring different circuits within the residence that represents loads of different priority, with loads being shed and restored, according to their priority.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• PROBLEM STATEMENT
• AIM/OBJECTIVE OF THE PROJECT
• PURPOSE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• APPLICATION OF THE PROJECT
• SCOPE OF THE PROJECT
• PROBLEM OF THE PROJECT
• LIMITATION OF THE PROJECT
• DEFINITION OF TERMS
• METGODOLOGY
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

• OVERVIEW OF THE STUDY
• OPERATIONAL REVIEW OF A TRANSFER SWITCH
• TYPES OF TRANSFER SWITCH
• MANUAL TRANSFER SWITCH OR CHANGEOVER SWITCH
• BENEFITS OF AUTOMATIC TRANSFER SWITCH OVER A MANUAL TRANSFER SWITCH
• PROTECTING THE POWER SYSTEM FROM FAILURE
• RESTORING POWER AFTER A WIDE-AREA OUTAGE

CHAPTER THREE

METHODOLOGY

• WORKING PRINCIPLE
• SYSTEM CIRCUIT DIAGRAM

CHAPTER FOUR

TESTING AND RESULTS

• CONSTRUCTION PROCEDURE AND TESTING
• INSTALLATION OF THE COMPLET DESIGN
• ASSEMBLING OF SECTIONS
• TESTING, TROUBLESHOOTING AND REMEDY
• ECONOMIC OF THE PROJECT
• PROJECT VIABILITY
• PROJECT RELIABILITY
• PROJECT MAINTAINABILITY
• PROJECT EVALUATION

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION

REFERENCES

 CHAPTER ONE

1.0                                                        INTRODUCTION

1.1                          BACKGROUND OF THE PROJECT

Automatic Transfer Switch ATS is a device for initiating an automatic changeover from mains supply to generator supply through many intermediate transfer stages which involves activating the fuel valve, choke valve and the generator starter.

But with an Automatic Transfer Switch, everything is fully automatic. When the utility power goes out, the transfer switch signals your generator to start. Once the generator is running the transfer switch automatically connects your home or business to the generator. When the utility power is restored, the transfer switch reconnects your home or business to the utility. Then it turns off your generator and waits for the next power outage. This helps you to save fuel costs and it is much safer because of its user-free operation (William D, 1975).

For example, in a home equipped with a backup generator and an ATS, when an electric utility outage occurs, the ATS will tell the backup generator to start. Once the ATS sees that the generator is ready to provide electric power, the ATS breaks the home’s connection to the electric utility and connects the generator to the home’s main electrical panel. The generator supplies power to the home’s electric load, but is not connected to the electric utility lines. It is necessary to isolate the generator from the distribution system to protect the generator from overload in powering loads in the house and for safety, as utility workers expect the lines to be dead.

When utility power returns for a minimum time, the transfer switch will transfer the house back to utility power and command the generator to turn off, after another specified amount of “cool down” time with no load on the generator (Fowler, 2011).

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 transfer switch was invented. 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 OF THE PROJECT

The main aim of any electric power supply in the world is to provide uninterrupted power supply at all times to all its consumers. Although, in developing countries such as Nigeria, the electric power generated to meet the demands of the growing consumers of electricity is insufficient, hence power instability and outage becomes the order of the day.

In view of these considerations, this project is aimed at building a workable automatic transfer switch which switches ON power from power Holding Company (PHCN) to a generator when power fails and from generator to PHC when power comes back and then shut down the generator automatically.

1.4                                              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                                         SIGNIFICANCE OF THE PROJECT

• Automatic Transfer Switches are used to insure the continuity of power supply, although this can mean different things in different situations. In a typical home, small business or institution, continuous power may mean that a short interruption can be tolerated. For example, if a backup generator is used to supply backup power when public utility power fails, there will be a pause while the generator starts up. In a hospital any interruption of more than a few seconds may be catastrophic. There are several ways that ATS can insure that the interruption is very brief – including batteries to fill in the gap from the cessation of public utility power to the start of backup generator supply. Some automatic switches sense the temporary dips and spikes in public utility power that precedes failure and starts up the generator before the complete failure of public power.
• 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.

1.6                           APPLICATION OF THE PROJECT

Some common examples of entities that implement automatic switches out of necessity are: hospitals, data centers, jails and prisons, fire departments, defense organizations, and police departments.

1.7                                              SCOPE OF THE PROJECT

This work covers only an automatic transfer switch. An automatic transfer switch is a device used to reroute power in special circumstances. For example, during a natural catastrophe the public utility power may go out at a hospital and the automatic transfer switch starts the back-up generator.

1.8                                              PROBLEM OF THE PROJECT

May occasionally respond to false signals: When an automatic switch senses signals in a building’s primary power supply that seem to indicate an impending power outage, it switches the building from utility feed to generator feed to avoid the coming outage. However, some transfer switches have been known to respond to false signals, a scenario that could waste generator power, albeit in small amounts.

Usually costs more than a manual model: Because automatic models are generally larger and contain more complex components than manual models, they usually cost more. However, their price tag varies according to the style of switch a building needs and what brand is purchased. An emergency power solutions provider is the best entity to consult about switch choice.

Needs more maintenance than a manual model: Manual models typically involve less maintenance because they involve less complex components, particularly in terms of testing maintenance and replacement parts. An emergency power solutions provider is the best entity to consult about transfer switch maintenance.

• LIMITATION OF THE PROJECT

1. It requires maintenance because they involve less complex components, particularly in terms of testing maintenance and replacement part.
2. The cost of designing the device is higher the parts are higher than that of the manual changeover.

• An automatic transfer switches have been known to respond to false signals when the switching device becomes faulty, this scenario that could waste generator power, albeit in small amounts.

1. Operating voltages: 220V-240
2. 60A is the maximium load it can handle.

1.10                                               DEFINITION OF TERMS

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.

1.11                                       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 device was carried out.
2. Studying of various component used in circuit.
3. Construction of the circuit was carried out.

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

1.12                                                      PROJECT ORGANIZATION

The work is organized as follows: chapter one discuses the introductory part of the work,   chapter two presents the literature review of the study,  chapter three describes the methods applied,  chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations