Design And Construction Of An Arduino Based Automatic Transfer Switch For Three Phase Supply

ABSTRACT

The need to protect electrical appliances from electrical power fluctuation cannot be over emphasized. Most homes and office complexes where single-phase supply is needed are supplied with two or three phases of power supply to allow change from one phase to another when there is fluctuation or complete outage of power supply on a particular phase. This action is done manually and results in electric shock and damages. The automatic phase selector system automatically select and switch from one phase to the other in a RED-YELLOW-BLUE sequence and operates within a voltage range of 160V – 220V. When voltage supply on a phase is below 160V or above 220V, this system automatically disconnects the load from the phase and connects to another where the required condition is met. The system was developed using Atmega328P microcontroller, ULN2003AN transistor switch, relays, 78XX series regulators, liquid crystal display and an audio alarm unit that produces a beep sound whenever there is a change from one phase to another. The load is connected on this phase and remains on it when the condition of operation is met. This sequence provides protection and guarantees continuous power supply for single-phase appliances and the designed system performed satisfactorily.

CHAPTER ONE

1.0                                              INTRODUCTION

1.1                             BACKGROUND OF THE PROJECT

In developing countries like Nigeria, power instability and phase failure has posed a serious threat to our economic development. One of the factors that boost the economy of a country is its ability to supply a steady and stable power supply. However, issues such as phase failure, phase imbalance or earth fault are main causes that lead to unstable and erratic power supplies [A.F. Agbetuyi, 2011]. In some cases, the power lines are over loaded leading to power trip-off by the circuit breakers or by the load shading process undertaken by distribution authority. Most homes and office complexes where single phase supply is needed are supplied with two or three phases power supply to allow change from one phase to another when there is fluctuation or complete outage of power supply on a particular phase. This action is aimed at making sure that power is always available for use by the appliances, but it is accompanied with its hazard because it is manually controlled; Hence, the need for an automatic control (switching) system. The automatic switching systems can help to eliminate the manual control technique mostly used in developing countries [E.J Oduobuk, 2014]. Several works have been done in this regard, some of which interfaced three-phase supply to generators using various approaches with remarkable success over the years [E.J Oduobuk, 2014].

1.2                                                  PROBLEM STATEMENT

Power failure, under and over voltage in a country, state or city is highly detrimental to development in public and private industries. The insecurity associated with these problems brings about limitation to power consistent investments, thus hampering the development of industries and multinational ventures. Processes like carrying out surgical operations in hospitals, laboratories which require constant power supply for research, money transactions between banks and more require constant use of uninterrupted power. In other to solve this problem, an automatic transfer switch was invented. This research covers the design and construction of a three phase automatic transfer switch using arduino.

1.3                                  AIM OF THE PROJECT

The main aim of this work is to build a three phases device that allows change from one phase to another when there is fluctuation or complete outage of power supply on a particular phase. This device will overcome power fluctuation phase interruption by selecting next most healthy available phase to feed the equipment using arduino as the heart of the project.

1.3                                          OBJECTIVE OF THE PROJECT

The objective of this work is to design a

1.4                                              PURPOSE OF THE PROJECT

The main purpose of this work is to ensure uninterruptible and healthy power supply.

1.5                                      SIGNIFICANCE OF THE PROJECT

Industries require three phases power to run their machinery. Some of them require continuous \ uninterrupted power to maintain their data

An automatic transfer switch introduces an automatic solution to overcome power fluctuation \ phase interruption by selecting next most healthy available phase to feed the equipment [ Fowler, Nick 2011].

It has the capacity to automatically switch power from  national grid to generator and vice versa, once there is power failure in any of the two power supplies and at the same time has the capacity of shutting down a generator set once the mains grid is been restored according to Theo. Audel and Co, 1998.

1.6                                              SCOPE OF THE PROJECT

This work covers only a three phase automatic transfer switch which can only be used for providing a means of switching from one phase of AC mains to another in the case of failure, under-voltage or over-voltage in the existing phase.

1.7                                          APPLICATION OF THE PROJECT

This device is used in the following places [Theo. Audel and Co, 1998]

1. home,
2. office,
3. worship places
4. workshops or industries
   • LIMITATION OF THE PROJECT
5. It requires maintenance because they involve less complex components, particularly in terms of testing maintenance and replacement part.
6. The cost of designing the device is higher the parts are higher than that of the manual transfer switch.

• Transfer switches have been known to respond to false signals when the switching device becomes faulty, this scenario that could waste generator power, albeit in small amounts.

1. Operating voltages: 160V-220
2. It is designed for a three phase supply

1.9                                                        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 device is carried out

• Finally, the whole device was cased and final test was carried out.

1.10                                                      DEFINITION OF TERMS

POWER OUTAGE / POWER FAILURE: A power outage is the loss of the electrical power network supply to an end user.

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.

1.11                          PROJECT ORGANISATION

The work is organized as follows: chapter one discuses the introductory part of the work, chapter two presents the literature review of the study, chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.