Design And Construction Of 5KVA Distribution Transformer Of 240/110V, 24V, 12V

ABSTRACT

This project work is titled design and construction of 5kva distribution transformer of 240/110v, 24v, 12v.

A distribution transformer is a transformer that provides the final voltage transformation in the electric power distribution system, stepping down the voltage used in the distribution lines to the level used by the customer.

If mounted on a utility pole, they are called pole-mount transformers. If the distribution lines are located at ground level or underground, distribution transformers are mounted on concrete pads and locked in steel cases, thus known as pad-mount transformers.

Distribution transformers normally have ratings up to 200 kVA, although national standard may describe units up to 5000 kVA as distribution transformers. However, the aim of this particular project is to design and constructs a distribution transformer of 5KVA with output taps of 240/110v, 24V and 12V respectively.

TABLE OF CONTENTS

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

CHAPTER ONE

1.0                                          INTRODUCTION

A distribution transformer is a transformer that provides the final voltage transformation in the electric power distribution system, stepping down the voltage used in the distribution lines to the level used by the customer. The invention of a practical efficient transformer made AC power distribution feasible; a system using distribution transformers was demonstrated as early as 1882.

If mounted on a utility pole, they are called pole-mount transformers. If the distribution lines are located at ground level or underground, distribution transformers are mounted on concrete pads and locked in steel cases, thus known as pad-mount transformers.

Distribution transformers normally have ratings up to 200 kVA, although national standard may describe units up to 5000 kVA as distribution transformers. Since distribution transformer are energized for 24 hours a day (even when they don’t carry any load), reducing iron losses has an important role in their design. As they usually don’t operate at full load, they are designed to have maximum efficiency at lower loads. To have a better efficiency, voltage regulation in these transformers should be kept minimum. Hence they are designed to have small leakage reactance.

1.1        CLASSIFICATION OF DISTRIBUTION TRANSFORMER

Distribution transformers are classified into different categories based on certain factors such as:

• Mounting location – pole, pad, underground vault
• Type of insulation – liquid-immersed or dry-type
• Number of Phases – single-phase or three-phase
• Voltage class
• Basic impulse insulation level (BIL).

1.2                     USE OF DISTRIBUTION TRANFORMER

Distribution transformers are normally located at a service drop, where wires run from a utility pole or underground power lines to a customer’s premises. They are often used for the power supply of facilities outside settlements, such as isolated houses, farmyards or pumping stations at voltages below 30 kV. Another application is the power supply of the overhead wire of railways electrified with AC. In this case single phase distribution transformers are used.

The number of customers fed by a single distribution transformer varies depending on the number of customers in an area. Several homes may be fed off a single transformer in urban areas; rural distribution may require one transformer per customer. A large commercial or industrial complex will have multiple distribution transformers. Padmount transformers are used in urban areas and neighborhoods where the primary distribution lines run underground. Many large buildings have electric service provided at primary distribution voltage. These buildings have customer-owned transformers in the basement for step-down purposes. In a secondary network system as used in urban areas, many distribution transformers may be connected in parallel, each equipped with its own network protector circuit breaker to isolate it from the secondary network in case of a fault.

Distribution transformers are also found in the power collector networks of wind farms, where they step up power from each wind turbine to connect to a substation that may be several miles (kilometers) distant.

1.3                             OBJECTIVE OF THE PROJECT

The main object of this particular project is to design and constructs a distribution transformer of 5KVA with output taps of 240/110v, 24V and 12V respectively.

1.4                          SIGNIFICANCE OF THE PROJECT

Distribution transformer is normally located at a service drop, where wires run from a utility pole or underground power lines to a customer’s premises. They are often used for the power supply of facilities outside settlements, such as isolated houses, farmyards or pumping stations at voltages below 30 kV. Another application is the power supply of the overhead wire of railways electrified with AC. In this case single phase distribution transformers are used.

The number of customers fed by a single distribution transformer varies depending on the number of customers in an area. Several homes may be fed off a single transformer in urban areas; rural distribution may require one transformer per customer. A large commercial or industrial complex will have multiple distribution transformers. In urban areas and neighborhoods where the primary distribution lines run underground, padmount transformers, transformers in locked metal enclosures mounted on a concreted pad, are used. Many large buildings have electric service provided at primary distribution voltage. These buildings have customer-owned transformers in the basement for step-down purposes.

Distribution transformers are also found in the power collector networks of wind farms, where they step up power from each wind turbine to connect to a substation that may be several miles (kilometres) distant.

1.5                           ADVANTAGES OF THE PROJECT

1. Low cost
2. Useful in low voltage applications
3. Easy to repair
4. Non-intricate

1.6                                                     LIMITATION AND PROBLEM OF THE PROJECT

1. Inability to avoid high voltage surges
2. Low mechanical strength

1.7                                                                   APPLICATION OF THE PROJECT

They are often used for the power supply of facilities outside settlements, such as isolated houses, farmyards or pumping stations.

1.8                          PROJECT WORK ORGANIZATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

Chapter one of this work is on the introduction to the study. In this chapter, the background, significance, objective, application, advantages, limitation and problem of the study were discussed.

Chapter two is on literature review of this study. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.

Chapter five is on conclusion, recommendation and references.