Design And Construction Of An Automatic Changeover Switch With Multiple Switches

ABSTRACT

Power failure or outage in general does not promote development to public and private sectors. This paper presents the design and construction of an automatic power change-over switch that switches power supply from main supply to another standby supply and it does this automatically using op-amp. This device eliminates the challenge of a manual change-over system in a three different building/flat. This research covers the design and construction of a single phase automatic power changeover with 3-multiple switches. It has the capacity to automatically switch power from national grid to generator and vice versa, for two different rooms/flats. This was achieved by the use of electrical components such as resistors, capacitors, diodes, transistors, relay etc.

Key words: Single Phase Preventing, Switching, LM371, changeover switch, changeover switch.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1     BACKGROUND OF THE PROJECT

• PROBLEM STATEMENT
• AIM AND OBJECTIVES OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• APPLICATION AND ADVANTAGES OF THE PROJECT
• SCOPE OF THE PROJECT
• DEFINITION OF TERMS
• PROJECT ORGANISATION

CHAPTER TWO – LITERATURE REVIEW

2.1     OVERVIEW OF RELEVANT TECHNOLOGY

2.2     REVIEW OF EXISTING SYSTEM

2.3     REVIEW OF RELATED WORKS EXISTING SYSTEM

2.4      REVIEW OF FUNDAMENTAL CONCEPTS

2.5     DESCRIPTION OF A RELAY

2.6      HISTORY OF POWER FAILURE AND SYSTEM RELIABILITY

2.7      TYPES OF POWER FAILURE

2.8       PROTECTING THE POWER SYSTEM FROM FAILURE

2.9      REVIEW OF THE THREE DIFFERENT SUPPLIES

2.10    SUMMARY OF REVIEWED WORKS

CHAPTER THREE

3.0         METHODOLOGY

3.1        SYSTEM BLOCK DIAGRAM

3.2        SYSTEM CIRCUIT DIAGRAM

3.3       SYSTEM OPERATION

3.4       DESCRIPTION OF COMPONNTS USED

CHAPTER FOUR

4.0       RESULT ANALYSIS

4.1     INSTALLATION OF THE COMPLETED DESIGN

4.2     CONSTRUCTION PROCEDURE AND TESTING

4.3     CASING AND PACKAGING

4.4      ASSEMBLING OF SECTIONS

4.5      TESTING OF SYSTEM OPERATION

CHAPTER FIVE

• CONCLUSIONS
• RECOMMENDATION

5.3     REFERENCES

CHAPTER ONE

1.0                                                INTRODUCTION

1.1                                  BACKGROUND OF THE STUDY

An automatic power changeover system designed and implemented basically disconnects load from its power source and transfers it to a standby power source, in the advent of a power failure. This transfer is done at a very high switching speed such that minimal change occasioned by the transfer process goes unnoticed. It also incorporates a generator shutdown terminal that switches off the generator after the mains power supply has been restored. This process is controlled by a controller that keeps sensing to detect the availability of power supply on the Main supply line (Ahmed et al., 2016). The system is also fitted with an AC voltmeter that correctly reads the analogue voltage supplied by the power source and displays it on a seven segment display module. The power change-over switch is a device that detects when the electrical energy from the mains power supply is cut off and subsequently switching on the power generator. Basically it is aimed at switching on a more convenient power supply to the load. Since it switches on power to the load, precautions has to be taken while choosing the type of change-over switch, of power generator to supply electrical energy that would power their homes whenever the supply from the electricity company is cut off. A power change-over switch enables this transfer. Power change-over switches can be operated manually in order words whenever there is power failure, an individual can shift a handheld lever that would open contact on the main power supply line and close contact on the power generator line. This process consumes time and puts such an operator at risk of electrical hazards (Ahmed et al., 2016).

The research project is designed for power supply applications. It involves automatic change over between the mains power supply and a standby generating set for a three different generator in a three different houses for a single phase power supply. Switching is possible through the use of the relays.  3-pressing switch is used for switching on and off of flats power source.

1.2                                   PROBLEM STATEMENT

In the last decay, switching from mains supply to solar inverter and vice –versa is done manually, and this involves labour, wastes time and at the same time can expose the operator to risk of electric shock. However, this device was invented to solve this problem, it switches automatically switches between the mains supply and generator when the need arise.

1.3                    AIM AND OBJECTIVE OF THE PROJECT

The main aim of this project is to design a device that will provide uninterrupted power supply to a load, by selecting from an available power source in a three different generator sources from a different houses/flats with a single phase mains supply. The objectives are:

1. To build the system model.
2. To use a single changeover switch to control three different load from a different flats / houses using a common single phase supply

• To protect our devices from power interruption.

1. To protect our investment by ensuring a steady power supply
2. To study relays and their connections
3. To supply power to more than one apartment using a single device

1.4                          SIGNIFICANCE OF THE PROJECT

This project provides an effective solution to provide an alternative power supply during frequent power cuts.

Using this device cuts the cost of having different changeover switch in a flat. This means that occupants of the three flat can make use of one changeover switch without been dependent of anyone standby power source (Generator) at any point in time.

Building this device is a way of minimizing damage to lives/equipment since it has its own monitoring system and its switching requires no human contact with the switch, thus eliminating human error.

It reduces its change over timing to the minimum due to its fast response to power outage.

It maintains high quality of service through its fast and prompt response.

Moreover, the size and captivity of the unit will depend upon the load for which it will be used. The unit is also portable, easy, convenient and safe to install.

1.5        APPLICATION AND ADVANTAGES OF THE PROJECT

1. This system could be used in that places where we have different sources of supply such as main and generator/ solar.
2. This system could be used in industries for supplying the uninterruptable power supply to the industrial machines.
3. This system could be used in educational institutes and hospitals for supplying the uninterruptable power supply to the hospital or educational equipment.
4. This system is more compact and reliable as compared to the electrical ATS panels.
5. This system is less costly as compared to the other power control systems.
6. The device can be used in house where all occupants of the different flats have a common engine house.

1.6                                  SCOPE OF THE PROJECT

The scope of this study covers building a changeover with 3 switches. It involves automatic change over between the mains power supply and a standby generating set for a three different generator in a three different houses/flats for a single phase power supply. Switching is possible through the use of the relays.  3-pressing switch is used for switching ON and OFF of flats power source.

1.7      DEFINITION OF TERMS

CHANGEOVER: Generally, a changeover is a system which could be operated manually or automatically , that changes one source of power supply to another source in case of power failure from either of the four sources.

RELAY: relay is one of the major components used in this work which is an electrical device, typically incorporating an electromagnet, which is activated by a current or signal in one circuit to open or close another circuit.

POWER FLUCTUATIONS: is a periodic dip or spikes in the electrical current of any given circuit.

POWER FAILURE: is a short- or long-term loss of the electric power to an area.    

1.8                                        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 this study. In this chapter, the background, significance, objective limitation and problem of this 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.

CHAPTER FIVE

5.1   CONCLUSIONS

In this research work, the simulation and construction of an efficient and cost effective single phase microcontroller based automatic changeover switching system was achieved. This circuit has the ability to accurately monitor the power supply from the national grid of the Power Holding Company and respond appropriately upon a power outage by starting a standby generator to supply power. Upon the restoration of utility power, the system changes the load back to utility and shuts down the generator.

Due to the looping of the pole of the contactor to give 50A current each for PHCN and generator, the maximum power the circuit can withstand or an ac voltage of 240V is 12KVA. This means the circuit can carry a large amount of power in homes and offices. This project saves resources like time, energy and even lives while ensuring automatic and efficient power load sharing from the consumer end. This project does not have any restriction in the aspect of who to use it and who not to use it nor where to use it and where not to use it. Its applications range from domestic homes, light industries and heavy industries.