design and construction of step up transformer with multiple output

Description

ABSTRACT

Transformer is the heart of a sub-station’s equipment, which primarily transforms voltage from one level to the other at the same frequency. The voltage can be raised (Step-up transformer) or lowered (Step-down transformer), but with a fractional decrease or increase in current ratings. Presented in this paper, is the design and implementation of a 2 kVA, 230/400,  600 and 800V, core-type transformer. The materials used were copper wire, silicon steel laminations and is air cooled. A comprehensive design calculation of different parts of the transformer was carefully carried out based on some already established basic transformer design assumptions. E-shaped laminations were 109 and the I-shaped laminations were 93. Pre-commissioning tests such as continuity, short and open circuit test were conducted satisfactory. This reduction in efficiency was as a result of occurrence of losses and heat generated within the transformer. The potential caused of these losses and transformer heating could be attributed to the method of implementation such as the punching of bolt holes and during the cutting of sizes of the metal sheets. The designed transformer finds application in practical classes in undergraduate Electrical Machine Laboratory and domestic use.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• PROBLEM STATEMENT
• AIM AND OBJECTIVE OF THE PROJECT
• SCOPE AND LIMITATION OF THE PROJECT
• RELEVANCE OF THE WORK
• APPLICATION OF THE PROJECT
• DEFINITION OF TERMS
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

• REVIEW OF THE STUDY
• HISTORICAL BACKGROUND OF THE PROJECT
• CLASSIFICATION PARAMETERS OF TRANSFORMER
• REVIEW OF DIFFERENT TYPES OF TRANSFORMER
• OTHER TYPES OF TRANSFORMERS

CHAPTER THREE

SYSTEM DESIGN METHODLOGY

• CIRCUIT DIAGRAM OF A STEP DOWN TRANSFORMER
• BASIC WORKING PRINCIPLE OF A TRANSFORMER
• TRANSFORMER CONSTRUCTION
• CIRCUIT DISCRIPTION OF A STEP-DOWN TRANSFORMER
• M.F EQUATION OF A TRANSFORMER
• DESIGN CALCULATION

CHAPTER FOUR

• TESTING, MEASUREMENT AND RESULTS
  • TESTING OF TRANSFORMER OPERATION
  • SHORT-CIRCUIT TEST
  • FAULT WITHSTAND
  • TRANSFORMER COOLING METHODS
  • HOW TO CHECK A STEP DOWN TRANSFORMER

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION
• REFERENCE

 CHAPTER ONE

1.0                                        INTRODUCTION

1.1                                 BACKGROUND OF THE PROJECT

A transformer is a static electromagnetic device that transfers energy by inductive coupling between its winding circuits. In another way, a transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. Electromagnetic induction produces an electromotive force within a conductor which is exposed to time varying magnetic fields. A varying current in the primary winding creates a varying magnetic flux in the transformers core and thus a varying magnetic flux through the secondary winding. This varying magnetic flux induces a varying electromotive force (e.m.f) or voltage in the secondary winding. Transformers are used to increase or decrease the alternating voltages in electric power applications. In simple terms, it is an electromagnetic device that steps up or steps down voltages. Making use of Faraday’s Law (discovered in 1831) in conjunction with high magnetic permeability core properties, transformers can be designed to efficiently change AC voltages from one voltage level to another within power networks (Gottlieb, 2012.).

A wide range of transformer designs are used in electronics and electric power applications. Transformers are essential for the transmission, distribution and utilization of electric energy. There are many sizes, shapes and configurations of transformers from tiny to gigantic like those used in power transmission.  Some come with stubbed out wires, others with screw or spade terminals, some made for mounting in PC boards, others for being screwed or bolted down.

Transformers are composed of a laminated iron core with one or more windings of wire.  They are called transformers because they transform voltage and current from one level to another.  An alternating current flowing through one coil of wire, the primary, induces a voltage in one or more other coils of wire, the secondary coils.  It is the changing voltage of AC current that induces voltage in the other coils through the changing magnetic field. DC voltage such as from a battery or DC power supply will not work in a transformer.

Only AC makes a transformer work.  The magnetic field flows through the iron core.  The faster the voltage changes, the higher the frequency (Edward, 2011). However, the output of transformers various from single to double or multiple.

1.2                                 PROBLEM STATEMENT

There has been the need of transmitting power over long distances with higher efficiency and low maintenance. Step-up transformers are what allow electricity to be transmitted over long distances at low prices. By increasing the voltage of the current that has to be transmitted, the resistance on the line is reduced. This ensures that there are fewer losses along the way. If this were not the case, the power loss on the transmission lines would be so large that it would almost make it impossible for electricity to reach all the places that it does so efficiently today. Also they also don’t need much maintenance. The only maintenance required includes checking the oil, cleaning the contacts, repairing any parts that have been damaged or corroded etc. All of these don’t require much time or money.

1.3                        THE AIM AND OBJECTIVES OF THE PROJECT

The aim of this study is to design and construct 2KVA step up with multiple taps. The objectives are as follows;

1. To design a step up voltage device
2. To study the working and construction a step up transformer

• To increase the efficiency of power supply.

1. To have different voltage output in a simple transformer.

1.4                        SCOPE AND LIMITATION OF PROJECT

The scope of this project is focused on the construction of step up transformer with input voltage of 230v and output voltage of 400, 600 and 800v. Therefore, the Transformers are used only for stepping up AC voltages or the Alternating Currents. They do not work on the DC or the Direct Current. The limitation are only for the applications related to the AC operations.

As the Step Up Transformer continuously performs its task without any break, it needs a cooling system. Since the Step Up Transformer cannot be shut down to cool, there has to be a provision to attach a round the clock cooling system to the Transformers.

As the voltage capacity increases bigger the transformer size which will also include a bigger cooling system. This creates a bulky and huge Transformer occupying a larger space.

1.5                                  RELEVANCE OF THE WORK

The relevance of designing the step-up transformer cannot be overemphasized. This is because most electrical or electronic machines and equipment usually comes in various voltages which is solely done by the manufacturer. Also, the voltages as applied to countries are also different. Hence, the step up transformer could be utilized here in Nigeria for transmitting power to a long distance.

1.6             APPLICATIONS OF STEP UP TRANSFORMERS

Applications of Step Up Transformers include:

• Step Up transformers are found in the electronic devices such as Inverters and Stabilizers where in the Transformers help in stabilizing the low voltage to the higher voltage.
• It is also used in the Electrical Distribution of Power

1.7         DEFINITIONS OF TERMS

TRANSFORMER: A transformer is a magnetically coupled coil, a transformer rescues input current and send output voltage, be it step – up or step – down transformer it used in transmission of an electric power.

STANDARD WIRE GAUGE: These are specific number of a wine (coil) it is used in this project to gauge on 17 which has a diagram of 1.422m.
TRANSFORMER: It is a cutout shape rubber material with a hollow in the center and with grove around is to avoid electric link between the core and the coil.
VOLTMETER: This is the instrument used to measure the voltage across the circuit. It is connected in parallel to the winding.
INSULATOR: These are the material used to isolate two conductors from touching each other.
CASING: The outer cover of the transformer this serve is from external hazard was made of metal as earlier stated in our previous chapter.
THE SWITCH: This is a mechanical advice used to open and close a complete electric circuit. The multipurpose low voltage (AC) transformers are connected via switch to the power supply. The primary winding is connected to the power source and the other winding are secondary winding We have step – up transformer and step – down transformer. But in this context emphasis will be lay on the step – up auto transformer.

1.8                       PROJECT ORGANIZATION

The entire project is arranged in sections to allow proper report presentation and understanding. The first chapter: the introduction; defines some important concepts on the project and gives a brief description of the problems in the society which results in the need for underground cable fault detector, this also contains the objectives, scope and limitations of the project. The second chapter is the review of related literature which describes briefly the history and classification of developed fault location method. Chapter Three highlight design methodology. Chapter Four highlight on the implementation and testing. Chapter Five is all about the conclusions and recommendations.

CHAPTER FIVE

5.1                                                           CONCLUSION

Step up transformers are made using a core made from laminations of sheet steel stacked and either glued together with resin or banded together with steel straps. Where large numbers of transformers are made to standard designs, a wound C-shaped core is economic to manufacture. A steel strip is wrapped around a former, pressed into shape and then cut into two C-shaped halves, which are re-assembled on to the copper windings.

While the operating principles of transformers have remained the same for nearly a century, the challenges of maintaining and testing transformers have evolved along with transformer design and construction. Modern transformers are designed to closer tolerances than ever before. Proper testing is essential for evaluating the condition of a transformer. This predictive data will guide maintenance activities and help prevent catastrophic failure that damages downstream equipment and endangers personnel.

5.2                                                    RECOMMENDATION

This project is designed to be used in power transmission, and is fully alternating current (ac) with high voltage taps which be dangerous when exposed to the body for this reason it must be constructed and used by a qualified personnel.

Working on this topic as my project is a good idea and it comes at the right time. I am suggesting that this particular topic should also be given to other students both in higher and lower class.