The Design And Construction A 5Kva Automatic Voltage Stabilizer With Surge Arrestor

ABSTRACT

This work is on a 5kva Automatic Voltage Stabilizer. It is designed to meet up with the AC voltage safety, stability and accuracy demand in industries and in homes. Voltage stabilizers are useful in devices such as computer Power supplies, alternators and central power station generator plants, voltage stabilizer control the output of the plant. This project is designed to stabilize an AC input voltage of 160-250V to give an AC output voltage of 220V at 50Hz automatically. The automatic feature can be achieved by the electronics devices used such voltage comparator IC, electro-magnetic device (relay), auto- transformer and other electronics devices.

In this project, 5KW was designed to control and stabilize an AC input voltage of 160-250V to produce an output of 220V all at 50Hz with surge protecting device.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGMENT

ABSTRACT

TABLE OF CONTENTS

CHAPTER ONE

1.0      INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

1.2      AIM/OBJECTIVE OF THE PROJECT

1.3      SIGNIFICANCE OF THE PROJECT

1.4      SCOPE OF THE PROJECT

1.5      LIMITATION OF THE PROJECT

1.6      PROBLEM STATEMENT

1.7      APPLICATION OF THE PROJECT

1.8      DEFINITIONS OF TERMS

1.9      METHODOLOGY

1.10   PROJECT ORGANIZATION

CHAPTER TWO

2.0      LITERATURE REVIEW

• HISTORICAL BACKGROUND OF THE PROJECT
• STAGES IN THE DEVELOPMENT OF VOLTAGE STABILIZER
• STABILIZER GRADING
• TYPES OF STABILIZER

CHAPTER THREE

3.0      CONSTRUCTION METHODOLOGY

• BLOCK DIAGRAM
• CIRCUIT DIAGRAM
• CIRCUIT DESCRIPTION
• SYSTEM OPERATION
• SURGE PROTECTION CIRCUIT
• DESCRIPTION OF MAJOR COMPONENTS USED

CHAPTER FOUR

4.0      RESULT ANALYSIS

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

CHAPTER FIVE

• DISCUSSION, CONCLUSION AND RECOMMENDATION

5.1      DISCUSSION

• CONCLUSION
• RECOMMENDATION
• REFERENCES

CHAPTER ONE

1.0                                                     INTRODUCTION

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 [Harper C, 1977].

Voltage stabilizer is an electronic control circuit or device that 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 240 volt by stabilizer at output stage without any voltage fluctuation [Harper C, 1977].

A surge protector limits the voltage supplied to an electric device by either blocking or shorting current to reduce the voltage below a safe threshold. Blocking is done by using inductors which inhibit a sudden change in current. Shorting is done by spark gaps, discharge tubes, zener-type semiconductors, and MOVs (Metal Oxide Varistors), all of which begin to conduct current once a certain voltage threshold is reached, or by capacitors which inhibit a sudden change in voltage. Some surge protectors use multiple elements.

The most common and effective way is the shorting method in which the electrical lines are temporarily shorted together until the voltage is reduced by the resistance in the power lines. The spike’s energy is dissipated in the power lines (and/or the ground), converted to heat. Since a spike lasts only 10s of microseconds, the temperature rise is minimal. However, if the spike is large enough, like a nearby hit by lightning, there might not be enough power line or ground resistance and the MOV (or other protection element) can be destroyed and power lines melted.

Surge protectors for homes can be in power strips used inside, or a device outside at the power panel. A modern house has three wires, Line, Neutral, and Ground (L,N, and G). Many protectors will connect to all three, in pairs, L-N,L-G,and N-G, since there are conditions, like lightning, where both L and N have high voltage spikes that need to be shorted to ground.

• BACKGROUND OF THE PROJECT

There are many fundamental different types of stabilizers in use some of which are electron mechanically tap changer, solid state tap changer etc. voltage, stabilizer came into being not by normal design and plain, but as a means of solving electrical “Crisis” situation.  This crisis situation does rarely occur in developed countries of the world such as Britain, American, Germany.

Their system of generation, transmission and distribution of electricity is such that a devoid of variation of fluctuation in the supplied voltage.  Now, by the definition given by K.G Jackson and R. Feinberg, a voltage stabilizer is a piece device incorporated in a circuit to maintain a constant output voltage from a poorly generated power supply.  A voltage stabilizer like any other piece of equipment is a combination of many electrical and like any other piece of equipment is a combination of many electrical and electronic and circuit with the aim of getting the assemble to perform a specified desired task or function [Oakes, I 1997].

1.3                                              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.

• AIM/OBJECTIVE OF THE PROJECT

This work is aimed at maintaining the stable voltage level to provide a constant supply in spite of any fluctuations or changes in supply in order to protect the home appliances. The device is produced or designed to perform the following functions which includes.

This device is used to step up and step down the voltage when the supply is faulty. It is an appliance that helps to prevent the life span of electronic any electrical and electric devices that makes the use of it.

It also brings out a filtered current which bring smothering the components that can make use of it.  This system can be called an automatic machine because it perform the functions of automatic system in which by changing from one stage to another in order to feet the valuable current and voltage to the supplied by the components to makes use of it according [Oakes, I 1997].

The damages received by the society which ignored the use of automatic voltage regulator is so complicated that it cannot be mentioned in this project. But my advice to the society is to try as much as possible to make the use of automatic voltage regulation in their electrical and electronic components because it is a protective device [Oakes, I 1997].

1.5                                        SIGNIFICANCE OF THE PROJECT

The Automatic voltage stabilizer is a voltage stabilizer planned to mechanically sustain a constant voltage level. It is very device to maintain a constant voltage level. It can also use electromechanical components. It can be used majorly to regulate one or more DC or AC depending on the design. Therefore, the functions of this equipment are very wide and can be used majorly for various purposes. Electronic voltage stabilizer can be used majorly for various purposes. It has various functions like it can be used mainly for stabilizing the DC voltages that can be used by the processor and its main parts. In central power station generator plants and automobile alternators, voltage stabilizer controls the output of the plant according to [Oakes, I 1997]. In this distribution system, it may be installed at along distribution lines so that all clients recognize steady voltage self-regulating of how much power is drawn from the line. There are many functions of operating the AC depending upon the design. It is very good option to maintain the constant voltage level. Automatic voltage stabilizer is a superb invention of science, which is an electric device designed to authorize a constant voltage in a settable level. It is very helpful to maintain the preferred voltage for the generators within particular limits. The main working of it depends upon the laws of electromechanical physics. It consists of numerous vigorous and unreceptive electrical parts like thermostats, adopters and diodes. Apart from this, there are many reliable Automotive Suppliers in India that produce many kinds of equipments like generator, regulator and other major parts. They are well known for various kinds of functions and various specifications. They not only produce higher quality products, but also they will provide some additional benefits with the parts of these equipments. Auto Voltage stabilizer Generator is the most important part for great amplifier to work. Its types are many, but they are highly in functionality and better performance. They are well equipped with self functioning controls and starts up functions which make them very easy and useful to handle easily and completely. They have different sizes, shapes and colors. There are also automatic stabilizers which are so small that they can be easily places on a small printed circuit board. They are very easy and portable to handle. They may cover a higher volume of small house sometimes. Therefore, there is a wide variety in the automatic voltage stabilizer each has its own specifications [Oakes, I 1997].

1.6                                         THE SCOPE OF THE PROJECT

The design and construction of an Automatic Voltage stabilizer 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 [Jackson, K.G, 1981].

So, we are building or constructing this device to reduce risk and damages the fluctuation of current / voltage caused by power fluctuations.

1.7                                        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 AVS. When generator or utility power is restored, the AVS shall automatically restart. Upon turn on or restart, the output of the AVS shall not exceed the specified output regulation limits [Michael T, 1993].

If the input voltage or frequency exceeds programmable minimum or maximum set points for a programmable time period (factory set for 10 seconds), the AVS shall electronically shut off. When electrical parameters are back within acceptable limits for a programmable time period (factory set for 60 seconds), the AVS 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 AVS shall electronically shut off and require a manual restart.

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

Surge: a surge protection circuits protects the device from damages cause by spike.

1.8                                               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.

1.9                                      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.

1.10                                      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.

1.11                                                  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.

1.12                                                  METHODOLOGY

In building this project, 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.

• Design and calculation for automatic voltage stabilizer.

1. Studying of various component of automatic voltages stabilizer circuit.
2. Construct a automatic voltages stabilizer circuit.

1.13                                  PROJECT WORK ORGANISATION

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.