Design And Construction Of A 5Kva Utility Voltage Conditioner For Critical Load Protection

ABSTRACT

An automatic Voltage regulators are used for many appliances in homes, offices and industries. The mains supply suffers from large voltage drops due to losses on the distribution lines en route. A voltage regulator maintains the voltage to the appliance at the nominal value of around 220 volts even if the input main fluctuates over a wide range.

The circuit, when used with any appliance, will maintain the voltage at around 220V even if the input mains voltage varies between 90V and 240V.

 TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGMENT

ABSTRACT

TABLE OF CONTENTS

 CHAPTER ONE

1.0      INTRODUCTION

1.1      PURPOSE OF THE PROJECT

1.2      AIM OF THE PROJECT

1.3      OBJECTIVE OF THE PROJECT

1.4      SIGNIFICANCE OF THE PROJECT

1.5      SCOPE OF THE PROJECT

1.6      LIMITATION OF THE PROJECT

1.7      APPLICATION OF THE PROJECT

1.8      DEFINITION OF TERMS

1.9      METHODOLOGY

1.10   PROJECT ORGANIZATION

CHAPTER TWO

2.0      LITERATURE REVIEW

• INTRODUCTION
• OVERVIEW OF POWER SYSTEM CONTROL
• AUTOMATIC VOLTAGE REGULATION CONCEPT
• OVERVIEW OF VOLTAGE REGULATOR

2.5            REVIEW OF DIFFERENT TYPES OF VOLTAGE REGULATORS

• OVERVIEW OF AN AUTO TRANSFORMER
• REGULATOR SPECIFICATION

 CHAPTER THREE

3.0      CONSTRUCTION METHODOLOGY

• BASIC OF THE SYSTEM
• BLOCK DIAGRAM
• CIRCUIT DIAGRAM
• CIRCUIT DESCRIPTION
• SYSTEM OPERATION
• THEORY OF MAJOR COMPONENTS USED
• HOW TO ASSEMBLE THE CIRCUIT
• HOW TO SET UP AND TEST THE CIRCUIT
• PARTS LIST
• DESIGN OF TRANSFORMER
• TRANSFORMER DESIGN ANALYSIS
• TRANSFORMER WINDING

CHAPTER FOUR

4.0      RESULT ANALYSIS

• CONSTRUCTION PROCEDURE
• CASING AND PACKAGING
• ASSEMBLING SECTION
• SYSTEM TESTING

CHAPTER FIVE

• DISCUSSION, CONCLUSION AND RECOMMENDATION

5.1      DISCUSSION

• CONCLUSION
• RECOMMENDATION
• REFERENCES

CHAPTER ONE

1.0                                                     INTRODUCTION

1.1                                         BACKGROUND OF THE PROJECT

In Nigeria and some other parts of the world today, the electricity power supply to consumers (at homes and industries) are not maintained at a stipulated voltage say 240 volts.  But the electronics gadgets and some other power operated machines, that we use in our homes, offices and industries requires power with constant or nearly constant voltage for their efficiency, and to avoid damage by the voltage.

The automatic voltage regulator is used to regulate the voltage. It takes the fluctuate voltage and changes them into a constant voltage. The fluctuation in the voltage mainly occurs due to the variation in load on the supply system. The variation in voltage damages the equipment of the power system. The variation in the voltage can be controlled by installing the voltage control equipment at several places likes near the transformers, generator, feeders, etc., The voltage regulator is provided in more than one point in the power system for controlling the voltage variations.

An automatic Voltage regulator is capable of providing a constant or nearly constant output voltage even when there is variation in load or input voltage as low as 90 volt can be boast up to 220 volt by stabilizer at output stage without any voltage fluctuation.

1.2                                              PROBLEM STATEMENT

The rate at which our appliances get burnt is higher most especially appliances without transformer such as our cell phone chargers and lanterns. And this problem is usually caused by either over voltage or under voltage. Due to this problems, a voltage stabilizer was designed which regulates under and over voltages to normal 220vac. An automatic voltage regulator regulates the AC voltage and keeps from lower or higher to normal. It protects any electronic device connected to it from getting damaged.

1.3                                               PURPOSE OF THEPROJECT

The main purpose of this study is to maintain constant voltage and power line conditioning to the equipment load under a wide variety of conditions, even when the utility input voltage, frequency or system load vary widely.

1.4                                                AIM OF THE PROJECT

The aim of this work is to construct a device whose function is to maintain constant voltage and power line conditioning to the equipment load under a wide variety of conditions, even when the utility input voltage, frequency or system load vary widely.

1.5                                          OBJECTIVE OF THE PROJECT

At the end of this work the device consisting of copper, multiple tapped, triple shielded isolation transformer and contain independently controlled inverse parallel electronic switches shall be designed.

Students involved shall be able to understand how to wind an autotransformer and how relays are been connected in other to perform the task.

1.6                                      SIGNIFICANCE OF THE PROJECT

An automatic voltage regulator does the following functions:

1. It controls the voltage of the system and has the operation of the machine nearer to the steady state stability.
2. It divides the reactive load between the alternators operating in parallel.
3. The automatic voltage regulators reduce the over-voltages which occur because of the sudden loss of load on the system.
4. It increases the excitation of the system under fault conditions so that the maximum synchronizing power exists at the time of clearance of the fault.

When there is a sudden change in load in the alternator, there should be a change in the excitation system to provide the same voltage under the new load condition. This can be done by the help of the automatic voltage regulator. The automatic voltage regulator equipment operates in the exciter field and changes the exciter output voltage, and the field current. During the violent fluctuation, the ARV does not give a quick response.

 1.7                                        THE SCOPE OF THE PROJECT

The design and construction of an Automatic Voltage Regulator is the project we are construction.  We are working on this machine because we have some idea on how this machine can be constructed and also on how it works.  We are also doing this because we want to learn more about it.

As we have mentioned earlier, this device is a protective device that protects our electrical and electronic appliances out of current and voltage fluctuation. This is how it works.  When this system is plugged into the socket or supply, it will receive a minimum voltage of 100v and filter the current and voltage thereby brings out suitable voltage output to be used by the devices in it.

So, we are building or constructing this device to reduce risk and damages the fluctuation of current / voltage caused by power fluctuations.  Before building this device, the following points and specifications should be kept in mind so that the device we build can work properly and give us the desired results:

• The range of input voltage should be 90 to 260V.
• The range of output voltage should be 200V to 240V.
• There should be no change in the waveform or the frequency of input/output voltages.
• The material used in it should not be too much expensive otherwise there would be no use of making it at home by going through all the trouble, can just buy a cheap one from market instead. Therefore it should not be expensive.
• No varistors or variable resistors should be present in the final form of the product.
• A total of 4 relays are used in the circuit.
• The auto transformer used has 4 additional tappings set at 165V, 190V, 215V and 220V, all with a difference of about 25V.

1.8                                        LIMITATION OF THE PROJECT

The system design shall be capable of operating at an input frequency range of -15% to +10% of nominal, without clearing protective devices or causing component failure within the AVR. When generator or utility power is restored, the AVR shall automatically restart. Upon turn on or restart, the output of the AVR shall not exceed the specified output regulation limits.

If the input voltage or frequency exceeds programmable minimum or maximum set points for a programmable time period (factory set for 10 seconds), the AVR shall electronically shut off. When electrical parameters are back within acceptable limits for a programmable time period (factory set for 60 seconds), the AVR shall automatically restart to provide conditioned power to the load. If the input parameters are within acceptable limits, but the output voltage is outside of acceptable programmed limits, the AVR shall electronically shut off and require a manual restart.

The AVR shall be capable of operating at 100% rated load capacity continuously, 200% rated load for 10 seconds, 500% rated load for 1 second and 1000% rated load for 1 cycle. Operating efficiency shall be a minimum of 96%, typical at full load.

Transformer winding shall be continuous copper with electrostatic tripled shielding and K-13 rated for the purpose of handling harmonic currents.

Response Time: The AVR shall respond to any line voltage variation in 1/2 cycle while operating linear or non-linear loads, with a load power factor of 0.60 of unity. Peak detection of the voltage sine wave shall not be permitted to avoid inaccurate tap switching due to input voltage distortion.

Operating Frequency: The AVR shall be capable of operating at +10% to -15% of the nominal frequency, 50Hz or 60Hz.

Rating: this device shall be rated at 5kVA.

Access Requirements: The AVR shall have removable panels on the front, rear and sides as required for ease of maintenance and/or repair.

Metering: An input meter is provided to display line voltages

Ventilation: The AVR isolation transformer shall be designed for convection cooling. If fan cooling is required for the solid state electronic switching devices.

Display: an LED indicators were used to indicate the power supply, delay, and when the system is in-use.

 

1.9                                         APPLICATIONS OF THE PROJECT

• Voltage regulator is used to automatically adjust the output voltage of the power supply circuit or power supply equipment
• It can be widely used in places require stable power supply voltage, such as industrial and mining enterprise, oil, railways, construction sites, schools, hospitals, telecommunications, hospitals, research and other department as of computer, precision machine tools, computer tomography(CT),precision instruments, test equipment, elevator lighting, imported equipment and production lines and more.

1.10                                                  DEFINITION TERMS

HV: High Voltage. Any electricity supply in excess of 650volts. Primarily used for the transmission of electricity over long distances.

Kva: Kilo volt amps. A measurement of the electrical ‘pressure’ and ‘quantity’ to a building.

Loads:  The equipment that is using the electricity supplied to a building.

Long power cut: Failure of the mains power external to your building, in excess of 30 minutes to 24 hours.

LV:  Low Voltage. Electricity supply from 110volts to 650 volts.

Power cut: A failure of the mains electricity by factors outside of your premises.

Prime rating: the rating given to a generator when it is used in lieu of mains power at a varying load. There is normally an overload allowed at this rating of 10% above the prime rating for 1 hour in 12.

Single phase power: The electricity produced from one phase of a three phase winding or from a dedicated singles phase winding.

Standby power: Maximum power a generator will give normally restricted to 1 hour in 12 for standby purposes only.

Winding: The copper wire that produces electricity when it passes through a magnetic field.

Watts: The total energy supplied by a circuit.

Surge: Overvoltage supply of electricity causing damage in sensitive equipment (opposite of Brown out).

Surge Suppression: Electronic equipment designed to restrain surges such as lightning strikes.

AVRs. Automatic voltage regulators. The electronic device which controls the output voltage of an alternator.

Base load rating. The rating given to a generator when it is used for continuous supply of electricity at a given load 24/7.

Black out. A national or wide area power failure, causing major disruption. For example.

Brown out. A drop in the mains voltage (not a total failure) that can cause degradation of lighting and electronic equipment.

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 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 works is on the introduction to an automatic voltage regulator. In this chapter, the background, significance, objective, aim, scope, limitation and problem, definition of terms of an automatic voltage regulator were discussed.

Chapter two is on literature review of an automatic voltage regulator. 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, discussion, recommendation and references.