Design And Construction Of An Automatic 3 Phase Supply Monitoring System With High And Low Voltage Protection

ABSTRACT

This project work is on the “automatic 3 phase supply monitoring system with high and low voltage protection”. It provides a means of monitoring and switching from one phase of AC mains to another in the case of failure, high and low in the existing phase; This project has been improved on the existing types of electromechanical device that has being in use over the years.

Hence this has been achieved by the use of operational amplifier, timing circuit and high current relay switches and it is powered by 12V dc power supply.
The aim of this work is to design and construct an Auto Phase monitor and Selector introduces an automatic solution to overcome power fluctuation/phase interruption by monitoring and selecting next most healthy available phase from three phase supply to feed the equipment without any notice of power outage.

TABLE OF CONTENTS

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

• INTRODUCTION
• AIM/OBJECTIVE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• PROBLEM STATEMENT
• LIMITATION OF THE PROJECT
• PURPOSE OF THE PROJECT
• APPLICATION OF THE PROJECT
• PROJECT ORGANISATION

CHAPTER TWO

2.0     LITERATURE REVIEW
2.1     REVIEW OF ELECTRICAL PHASES
2.2     REVIEW OF THREE-PHASE ELECTRIC POWER
2.3     REVIEW OF THREE PHASE GENERATION AND DISTRIBUTION
2.4   REVIEW OF THREE-PHASE LOADS

CHAPTER THREE

3.0      METHODOLOGY

3.1     BLOCK DIAGRAM OF THE SYSTEM

3.2     DESCRIPTION OF SOLAR INVERTER UNITS

3.3     SYSTEM CIRCUIT DIAGRAM

3.4      CIRCUIT OPERATION

3.5      THREE PHASE INPUT TO SINGLE PHASE OUTPUT

3.6     DESCRIPTION OF COMPONENTS USED

CHAPTER FOUR

RESULT ANALYSIS

4.0      CONSTRUCTION PROCEDURE AND TESTING

4.1      CASING AND PACKAGING

4.2      ASSEMBLING OF SECTIONS

4.3      TESTING OF SYSTEM OPERATION

4.4     COST ANALYSIS

CHAPTER FIVE

5.0      CONCLUSION

5.1      RECOMMENDATION

5.2      REFERENCES

CHAPTER ONE

1.0                                             INTRODUCTION

1.1                                       BACKGROUND OF THE STUDY

In Nigeria today the problems of power outage, under or over voltage across phases is so rampant thus leading to some sensitive equipment and appliances being redundant, this could sometimes be the cause of one phase going out with respect to the other according to [William D, 2009] .

It may surprise one to note that in an attempt to solve this problems, so many unskilled electricity consumers has in recent past resorted to some crude means of swapping between phases to obtain power. So many souls have been lost in this act. This is an undesirable condition to consumers and the need now arises to design a device that can automatically monitors and selects among the phases and make power supply available at the consumers’ terminal [William D, 2009].

However, this can only be possible if one have a three phase met or and there is supply from any of the service line or the entire line, this project known as a automatic three phase monitoring has been constructed with a view of solving the problems stated above. The design and construction was based on the principle of Electro magneto-Dynamism and alignment as demonstrated in the relay arrangement [Theo. Audel and Co, 1998].

In this work, Faults and how they are cleared is presented, however, there are no user serviceable parts in the device therefore all maintenance should be referred to a qualified electrical personnel [Cotton H, 2011].

1.2                                                  PROBLEM STATEMENT

Power failure / under and over voltage in a country, state or city is highly detrimental to development in public and private industries. The insecurity associated with these problems 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 these problems, an automatic three phase changeover switch was invented. This research covers the design and construction of an automatic 3-phase monitoring system with high and low voltage protection. It has the capacity to automatically monitor the three phases and switch one healthy phase from the three.

1.3                                          OBJECTIVE OF THE PROJECT

The objective of this work is to design a device that will overcome under or overvoltage in the three phase thereby leaving our appliances in a save condition.

1.4                                      SIGNIFICANCE OF THE PROJECT

Industries require three phases power to run their machinery. Some of them require continuous \ uninterrupted\ safe power to maintain their data. The device monitors the three phase and select one healthy phase automatically from three phases supply[ Fowler, Nick 2011].

1.5                                        LIMITATION OF THE PROJECT

In every home, office or industries, this device provides a means of switching from one phase of AC mains to another in the case of failure/low or over voltage in the existing phase; 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 the three phases short-circuiting, until a multiplexing circuit was gotten.
• Difficult in wiring because of the strong wiring the project required [ Fowler, Nick 2011].

1.6                                              SCOPE OF THE PROJECT

This work covers only an automatic three phase monitoring system with over and under voltage protection which can only be used for providing a means of monitoring the status of the three phase supply and thereby switching from one phase of AC mains to another in the case of failure, under or over voltages in the existing phase.

1.7                                          APPLICATION OF THE PROJECT

This device is used in the following places [Theo. Audel and Co, 1998]

1. home,
2. office,
3. worship places
4. workshops or industries

1.8                                                        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 device is carried out

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

1.8                                                         DEFINITION OF TERMS

POWER OUTAGE / POWER FAILURE: A power outage is the loss of the electrical power network supply to an end user.

LOW VOLTAGE: voltage less than the required voltage supply for consumers appliances ( in Nigeria, voltage supply for consumers is 220VAC. That means when the supply voltage is less than 220 VAC it is said to have low or under-voltage).

HIGH VOLTAGE: voltage higher than the required voltage supply for consumers appliances (in Nigeria, safe voltage supply for consumers is 220 – 240VAC. That means when the supply voltage is higher than 240 VAC it is said to have high or over voltage).

1.8                             PROJECT ORGANISATION

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.

CHAPTER TWO

2.0                                                LITERATURE REVIEW

2.1                                     REVIEW OF ELECTRICAL PHASES

There is a major characteristic of an AC electricity supply that requires explanation -phases. A DC circuit has two wires through which the current in the circuit flows from a source of electricity through a load and back to the source [Brittain J. E, 2007]. A single-phase AC circuit also has two wires connected to the source of electricity. However, unlike the DC circuit in which the direction of the electric current does not change, the direction of the current changes many times per second in the AC circuit. The 220 volt electricity supplied to our homes is single phase AC electricity and has two wires – an “active” and a “neutral” [Theo. Audel and Co, 1998]…