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DEVELOPMENT OF AN ARDUINO BASED POWER ANALYZER

HAMZAH BIN KAMARUDIN

UNIVERSITI SAINS MALAYSIA 2019

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DEVELOPMENT OF AN ARDUINO BASED POWER ANALYZER

by

HAMZAH BIN KAMARUDIN

Thesis submitted is fulfilled of the requirements for the degree of

Bachelor of Engineering (Electrical Engineering)

JUNE 2019

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ACKNOWLEDGEMENT

First and foremost, I would like to express gratitude and appreciation to my project supervisor and advisor for my Final Year Project (FYP), Ir Dr Teoh Soo Siang. He had given me the important information, guidelines, and steps for me to do this project. I am grateful as he provided me with many useful ideas, assistance and encouragement. His passion helped me a lot to coordinate my project especially in writing this report.

Furthermore, I would also like to acknowledge the crucial role of Electrical & Electronic Engineering staff Encik Mohammad Nazir Bin Abdullah as he provides me with information in configuring the LCD display. He also gave the permission to use all required equipment and the necessary materials to complete the task.

Finally, I would like to thank all my friends and my family who has provided me with various kind of help during the making of this project. Their supports and valuable comment suggestions has inspired me to improve the quality of the project.

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TABLE OF CONTENTS

ACKNOWLEDGEMENT ... ii

LIST OF TABLES ...vi

LIST OF FIGURES ... vii

LIST OF SYMBOLS ...ix

LIST OF ABBREVIATIONS ... x

ABSTRAK ...xi

ABSTRACT ... xii

INTRODUCTION ... 1

1.1 Background ... 1

1.2 Problem Statement ... 5

1.3 Research Objectives ... 6

1.4 Scope of Research ... 6

1.5 Thesis Organization ... 7

LITERATURE REVIEW ... 8

2.1 Introduction to Power Analyzer ... 8

2.2 Electric Power Meter ... 8

2.3 Nonintrusive Appliance Load Monitoring ... 11

2.4 Power Quality Monitor on Harmonic Measurement ... 15

2.5 TFT display configuration ... 17

2.6 Summary ... 19

METHODOLOGY ... 20

3.1 Introduction ... 20

3.2 Project Methodology ... 20

3.3 Project requirement ... 22

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3.3.1 Hardware development... 24

3.3.1(a) Arduino Mega 2560 ... 24

3.3.1(b) TFT LCD Colour Display Screen ... 25

3.3.1(c) Split Core Current Transformer ... 26

3.3.1(d) Voltage Sensor Module ... 29

3.3.2 Software development ... 30

3.3.3 Data analysis ... 32

3.3.3(a) Calculation of Parameters ... 32

3.3.1.3(a)(i) Calculation for RMS voltage (V) ... 32

3.3.1.3(a)(ii)Calculation of RMS current (A)... 33

3.3.1.3(a)(iii)Calculation of real power (W) ... 33

3.3.1.3(a)(iv)Calculation for apparent power (VA) ... 34

3.3.1.3(a)(v) Calculation for power factor ... 34

3.3.1.3(a)(vi)Calculation for Total Harmonic Distortion ... 34

3.4 Project Design and testing... 35

3.5 Summary ... 36

RESULTS AND DISCUSSION ... 37

4.1 Introduction ... 37

4.2 Signal Conditioning Circuit ... 37

4.2.1 Voltage Transformer Signal Conditioning ... 38

4.2.2 Current Transformer Signal Circuit ... 39

4.3 Experiment on The Developed Power Analyzer Device ... 40

4.3.1 Performance testing of the Power Analyzer ... 41

4.3.1(a) Test Results Using Hairdryer ... 41

4.3.1(b) Test Results Using Electric Kettle... 44

4.3.1(c) Test Results of Total Harmonic Distortion on Voltage ... 45

4.3.1(d) Discussion on the test results ... 46

4.3.1(e) Total Harmonic Distortion Discussion ... 47

4.4 Project Cost ... 51

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4.5 Summary ... 52

CONCLUSION AND FUTURE WORKS ... 53

5.1 Conclusion ... 53

5.2 Limitation of Power Analyzer Device ... 54

5.3 Future Works... 54

REFERENCE ... 55

APPENDICES ... 2

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LIST OF TABLES

Table 2.1 Test results of voltage harmonics [18] ... 16

Table 4.1 Results of Power Analyzer and Fluke Analyzer using Hair Dryer ... 42

Table 4.2 Results of Power Analyzer and Fluke Analyzer using Electric Kettle ... 44

Table 4.3 Test Results of Total Harmonic Distortion on Voltage ... 45

Table 4.4 Project Cost ... 51

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LIST OF FIGURES

Figure 1.1 Malaysia electrical consumption based on sectors (2000-2016) [1] ... 2

Figure 2.1 Block diagram of the system [10] ... 8

Figure 2.2 Non-invasive current sensor circuit [10] ... 9

Figure 2.3 SCT-013-000 Current transformer circuit [12] ... 10

Figure 2.4 Classification of system for monitoring electrical energy [13] ... 12

Figure 2.5 Non-intrusive appliance load monitoring (NIALM) system [15] ... 12

Figure 2.6 Home appliance load monitoring using NILM [14] ... 13

Figure 2.7 Voltage- current curve for different electrical appliances [17] ... 14

Figure 2.8 HIOKI PW3198 power quality analyzer [18] ... 15

Figure 2.9 Voltage waveform of monitoring point PC-02 and PC-03 [18] ... 17

Figure 2.10 Voltage waveform of recirculation box 1 and 5 [18] ... 17

Figure 2.11 Spatial colour synthesis of LCD [22] ... 18

Figure 2.12 LCD voltage control light switch [22] ... 18

Figure 3.1 Flow chart of the project methodology ... 21

Figure 3.2 System Block diagram ... 22

Figure 3.3 Connection diagram of the proposed system ... 23

Figure 3.4 Arduino Mega 2560 [23] ... 24

Figure 3.5 3.8 TFT LCD Colour Display Screen Module Mega2560 ... 25

Figure 3.6 SCT-013-000 Current transformer ... 26

Figure 3.7 Signal Conditioning for Current Transformer using multisim ... 28

Figure 3.8 AC Voltage Sensor Module C (Single Phase) [26] ... 29

Figure 3.9 MCUFRIEND and Adafruit-GFX libraries ... 31

Figure 3.10 Testing the TFT LCD display ... 31

Figure 3.11 Fluke Power Quality Analyzer ... 35

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Figure 3.12 THD of voltage settings on Fluke Power Quality Analyzer ... 36

Figure 4.1 Signal conditioning circuit for Current Transformer ... 37

Figure 4.2 Input waveform of the Voltage transformer ... 38

Figure 4.3 Input waveform of Current transformer before DC bias ... 39

Figure 4.4 Input waveform of Current transformer after applying DC bias ... 40

Figure 4.5 Calibration voltage and current using emon library ... 40

Figure 4.6 Hair Dryer Operation (OFF mode) ... 43

Figure 4.7 Hair Dryer Operation (Low Speed mode) ... 43

Figure 4.8 Hair Dryer Operation (High Speed mode) ... 43

Figure 4.9 Results of Electric Kettle ... 44

Figure 4.10 Total Harmonic Distortion Experiment ... 45

Figure 4.11 The Sampled Input Voltage Data When THD = 2.24% ... 48

Figure 4.12 Computed Magnitude of the Harmonic Components when THD = 2.24% ... 48

Figure 4.13 THD = 2.24% using power analyzer display ... 49

Figure 4.14 The Sample Input Voltage Data When THD = 11.6% ... 49

Figure 4.15 Computed Magnitude of the Harmonic Components when THD = 11.6% ... 50

Figure 4.16 THD = 11.6% using power analyzer display ... 50

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LIST OF SYMBOLS

P Real Power S Apparent Power Q Reactive Power PF Power Factor

THD Total Harmonic Distortion 𝐼𝑝𝑘−𝑝 Peak to Peak Primary Current 𝐼𝑝𝑘−𝑠 Peak to Peak Secondary Current 𝑉𝑚𝑒𝑎𝑛,𝑠𝑞 Mean Voltage Square 𝐼𝑚𝑒𝑎𝑛,𝑠𝑞 Mean Current Square

𝑛 Number of Samples

𝑉𝑠𝑢𝑚 Sum of Voltage 𝐼𝑠𝑢𝑚 Sum of Current

𝑃𝑖 Instantaneous Power 𝑉𝑖 Instantaneous voltage 𝐼𝑖 Instantaneous current 𝑃𝑠𝑢𝑚 Sum of Power

𝑉𝑓𝑢𝑛𝑑_𝑟𝑚𝑠 RMS Voltage of Fundamental Frequency

𝑉𝑛_𝑟𝑚𝑠 RMS Voltage of nth Harmonic

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LIST OF ABBREVIATIONS

AC Alternating Current

AMI Advanced Metering Infrastructure CCFL Cold Cathode Fluorescent Lamp DC Direct Current

FFT Fast Fourier Transform GND Ground

ICSP In-Circuit Serial Programming LCD Liquid Crystal Display

NIALMS Non-Invasive Load Monitoring Systems PWM Pulse Width Modulation

RGB Red, Green and Blue RMS Root Mean Square TFT Thin-Film Transistor

UART Universal Asynchronous Receiver/Transmitter USB Universal Serial Bus

VCC Input Voltage VI Voltage and Current

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PEMBANGUNAN PENGANALISIS KUASA BERASASKAN ARDUINO

ABSTRAK

Dalam projek ini, penganalisis kuasa dilaksanakan dengan menggunakan Arduino sebagai plat dalam mengukur dan menganalisis penggunaan kuasa peralatan elektrik, peralatan dan aplikasi. Peranti menganalisis kuasa sangat penting terutamanya dalam industri untuk mengelakkan kesalahan dalam sistem kuasa. Dengan menggunakan maklumat ini pengguna akan dapat mengenal pasti penyelewengan parameter elektrik serta harmonik yang tinggi supaya tindakan yang lebih baik dapat diambil untuk mencegah kerugian. Masalah dengan penganalisis kuasa semasa adalah sangat mahal.

Versi penganalisa kuasa yang lebih murah kebanyakan hanya memaparkan parameter asas penggunaan kuasa tanpa pengiraan harmonik. Tujuan projek ini adalah untuk mengurangkan kos merangka penganalisis kuasa berfungsi untuk penggunaan industri berskala kecil. Kawalan mikro Arduino bertindak sebagai pemproses utama dan mengumpul maklumat, melakukan pengiraan dan menganalisis data. Maklumat seperti arus RMS dan voltan RMS akan dikira untuk mendapatkan kuasa sebenar (P), kuasa nyata (S), faktor kuasa (PF) dan jumlah penyelewengan harmonik (THD). Semua data akan dipaparkan menggunakan paparan TFT LCD dan pengguna boleh mendapatkan maklumat masa nyata mengenai penggunaan elektrik sama ada beban untuk peralatan elektrik rumah mereka. Sistem prototaip telah dibina dan prestasinya akan diuji dengan membandingkan penganalisis kuasa dengan Penganalisis Kuasa Fluke. Kesalahan peratusan purata penganalisis kuasa untuk ujian pengering rambut berkelajuan rendah adalah 4.25%, cerek elektrik adalah 2.87% dan ralat peratusan THD adalah 32.64%.

Disimpulkan bahawa penganalisis kuasa boleh menggantikan penganalisis kuasa sedia ada di pasaran dengan kos yang lebih murah dan penggunaan yang lebih mudah.

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DEVELOPMENT OF AN ARDUINO BASED POWER ANALYZER

ABSTRACT

In this project, a power analyzer is implemented by using Arduino as a platform in measuring and analyzing the power consumption of electrical devices, equipment and application. A power analyzing device is very important especially in industries to prevent fault in power system. By having this information users will be able to identify the irregularities in electrical parameters as well as high Harmonic so a better action can be taken to prevent loss. The problem with the current power analyzer is that it is very costly. The cheaper version of most power analyzer only displays basics parameters of power consumptions with no harmonic calculation and display. The purpose of this project was to reduce the cost of designing a functional power analyzer for the usage of small-scale industries. The Arduino microcontroller acts as the main processor and collect information, perform calculation and analyze the sensors’ data. The information such as from RMS current and RMS voltage will be calculated to get real power (P), apparent power (S), power factor (PF) and total harmonic distortion (THD). All the data will then be displayed using a TFT LCD display as user can get the real time information on their consumption of electricity whether the load for their appliances or home. A prototype system has been constructed and its performance will be tested comparing the power analzer with a commercial Fluke Power Quality Analyzer. The average percentage error of the power analyzer for the testing of low speed hairdryer is 4.25%, electric kettle is 2.87% and the THD percentage error is 32.64%. It is concluded that the power analyzer can replace the existing power analyzer available on market with cheaper cost, easier usage and installation.

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INTRODUCTION

1.1 Background

As the world progress through technological advancement, electrical energy plays an important role to mankind. It is undoubted that electrical energy is one of the greatest technological discoveries as it is now become a part of our daily life. Electrical energy is one of the most important “raw materials” used in industry and households. Electrical energy is supplied through the transmission and distribution networks to the customers.

According to MEIH (Malaysia Energy Information Hub) the usage of electrical energy consumption in Malaysia increased rapidly from year 2000 to 2016. The total electrical consumption of the year 2000 was 5,262 ktoe (kilo tonnes of oil equivalent) which is equivalent to 61 Billion kWh increase drastically to 12,392 ktoe which is equivalent to 14 Billion kWh in the year 2016. The statistics of Malaysia electrical consumption was shown in Table 1.1 and Figure 1.1.

Table 1.1 Malaysia electrical consumption (2000-2016) [1]

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Figure 1.1 Malaysia electrical consumption based on sectors (2000-2016) [1]

The industrial electrical consumptions in Malaysia is the highest among all the consumptions and the demand and usage of electrical energy keep increasing throughout the year. Due to the increasing trend of energy usage in Malaysia as well as around the world it is necessary to seek a better solution Problems with the power quality take a wide range of problems in varying time ranges from ten nanoseconds throughout the time of the stabilized condition or steady state [2].

With the increase of non-linear loads in power systems, the voltage and current waveforms are becoming more distorted and power quality is deteriorating [3]. The efficiency of power quality will also decrease by the effect of harmonic in the system.

The increasing of non-linear loads in the industrial such as, monitor, computer and other electronic device affects degradation of power quality as it produce harmonic distortions which it can cause power quality problems such as increase of temperature in equipment, equipment malfunction and cause financial loss of the customers and electric power

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companies [4]. It is necessary to seek for a solution to solve the problem of increasing demand of electrical energy especially seeking parameters on harmonic in industries.

A power analyzer is a device used to measure parameters of electrical power in distribution system. It is often used to determine the power consumption of a system as well as to reduce the amount of waste produced. A power analyzer is also important to calculate loads for example calculation of costs associated with air conditioning, heating and on-site power generation. Based on this project Arduino will be used in measuring power consumption known as a device called power analyzer.

The present invention relates generally to systems for monitoring electrical power circuits and particularly to a programmable system for measuring and calculating electrical parameters from multiple power circuits. Traditional systems for monitoring power circuits require the installation of individual measuring devices to measure a specific power system parameter; for example, Watts, Vars, Amps, or Volts [5].

In this project Arduino Mega 2560 will be used as a microcontroller. The Arduino will be used to collect data of electrical appliances loads. This can be done by collecting data such as magnitude from current and voltage using current transformer and potential transformer. The Mega 2560 will act as a processor that process and measure data into information such as Current, Voltage, Active power, Power Factor and Harmonic components. The data will then be displayed using TFT LCD display.

Today, colour TFT (Thin-Film Transistor) LCDs are common even in cost- effective equipment’s. An LCD display system is composed of an LCD panel, a frame

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buffer memory, an LCD and frame buffer controller, and a backlight inverter and lamp [6]. The TFT LCD will be used as a medium to display all the data to consumers as well as the signal for total harmonic distortion of the system.

The information that will be obtained by the device is:

I. Root Mean Square Voltage II. Root mean Square Current III. Real Power

IV. Apparent Power V. Power Factor

VI. Total Harmonic Distortion

As the data will be displayed using TFT LCD displayed users can instantly get the information from the device and will be able to analyze the power consumptions of their electrical applications.

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5 1.2 Problem Statement

The main issue faced by industries is that the electrical fault occurs in a manufacturing industry. Fault in electrical may affect the entire production line to stop.

It may also cause incorrect machine operations and can even causes loss of life if this problem is taken lightly. Electrical fault main collateral damage is the loss of money which can affect the company economy.

Considering that as a problem, high demand of the electrical monitoring and analyzing had been developed and tested. The number of users rapidly increases as the power monitoring machine is important in checking their power consumption as well as fault in machines and equipment’s they are using. The problem with the current power analyzer is that it is very costly [7]. The cheaper version of most power analyzer only display basics parameters of power consumptions with no harmonic calculation and display.

The purpose of this project was to reduce the cost of designing a functional power analyzer for the usage of small-scale industries [7]. A power analyzer should be able solve the fault in electrical problems by displaying the Harmonic Distortion of the equipment’s used by user so fast action can be made to avoid serious loss. The power analyzer can calculate the usage of the electrical loads that they used. All the important parameters of power can also be displayed and viewed by users clearly thus will help them monitor the power consumptions of their equipment as well as the fault that might occur.

This device can also help to continuously detect and identify the equipment that causing poor power quality which can upset other sensitive equipment and causing faults

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[8]. In recent years, the use of nonlinear load has been increasing which results in poor power quality. Hence, it is necessary to develop a low-cost power analyzer to measure the harmonics contents in power supply which is a common type of distortion to power quality [9].

1.3 Research Objectives

The objectives of this research are:

➢ To reduce the cost of making a power analysing system that can be used to measure electrical parameters such as voltage, current, real, and apparent power and power factor using microcontroller.

➢ To develop a system that can analyze and display the Harmonics contents of a power system.

1.4 Scope of Research

This project focused on the development of a power analyzer for the usage of small industries as an alternative to commercial power meter which is more expensive.

This power analyzing device will help users to be able to monitor the power consumptions of their equipment’s. Parameters such as: RMS current, RMS voltage will real power, apparent power, power factor and total harmonic distortion (THD) can be measured and displayed to the user.

Problems in an electrical system can be detected by using this power analyzer.

Faulty equipment’s that runs with irregular power consumptions can also be detected and isolated to prevent it from affecting other equipment. In this project the testing will be done in the laboratory using electrical appliances data will be taken by this power analyzer and the results will be compared to the Fluke Power Quality Analyzer.

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7 1.5 Thesis Organization

This thesis consists of five chapter which is the introduction of this project as the first chapter. The first chapter will describe the research background, problem statement, research objectives and scope of research.

The second chapter is the literature review of the past studies on smart monitoring system and the real time monitoring system. This chapter will review all the past projects and research including the different methods that have been studied by different researchers.

Chapter three covers the methodology part of this project. This part will describe the design and concept of this project, hardware part, software and testing plan of the project. This chapter will consist of all the flow charts of the design and steps to accomplish this project.

Chapter 4 is the procedures of all the experiments carried out and results to put this project to test. All the result obtained will be analysed and discussion will be made and presented. The data taken from experiment and testing of the power analyzer will be showed and explained.

Lastly the fifth chapter will be the conclusion part. The conclusion part will summarize the overall project objectives. Limitation of the power analyzer, further improvement and suggestions for of the power analyzer project in the future will be discussed.

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LITERATURE REVIEW

2.1 Introduction to Power Analyzer

A power measuring equipment is a necessary tool in calculating electrical demand and to analyze power consumption from electrical appliances. As this project will be focusing more on the usage for industries, so this chapter will be discussing more on power analyzer base harmonic. This literature review will also discuss and focus on electrical monitoring devices that has been developed, harmonic parameters explanation and TFT display screen configuration.

2.2 Electric Power Meter

The measurement and analysis of electrical power quality is usually done by using a power analyzer meter. These power analyzer devices are more expensive and require trained personnel to operate or install [7]. Today, advances in electronic devices enable the development of cheaper meter with similar features and acceptable measurement error , such as the system proposed in Figure 2.1 [10].

Figure 2.1 Block diagram of the system [10]

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Comparing the system of power analyzer in Figure 2.1 with my power analyzer it uses ethernet shield which is essential in IOT system. The system also composed of a circuit for measuring voltage and a circuit for measuring current using two different types of sensors. A non-invasive that requires a coupling circuit and a non-invasive sensor that delivers the current signal adjusted to the microcontroller levels.

A power quality analyzer is a device to measure parameters of single-phase networks. The designed analyzer measures the following parameters: RMS Values of Voltages and Currents, power factor, Total harmonics distortion (THDu, THD1), Active, Reactive and Apparent power [11]. For home power monitoring design usually only two sensors will be used for current and voltage measurements. The processor such as Arduino will perform the measurement of the electrical power parameters as well. As for recording and displaying the data the parameters can be displayed using TFT display.

Then the measured data can be sent via USB or Ethernet to PC.

The voltage and current are the most fundamental parameters in a power measuring equipment. A current sensor output needs to be condition to meet the requirement of the Arduino analog input. The conditioning circuit was shown in Figure 2.2 and Figure 2.3.

Figure 2.2 Non-invasive current sensor circuit [10]

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In Figure 2.2 the current sensor used is ECS1030-L72 a non-invasive sensor capable of measuring loads up to 30 Amps. It is different than the sensor that is used in my power analyzer project that is SCT-013-000 Non-Invasive Split Core Current Transformer that is capable of measuring loads up to 100 Amps. The capacitor C1 serves as the signal filter and R1 and R3 provide polarization voltage. The power supply signals are taken directly from the microcontroller card.

Figure 2.3 SCT-013-000 Current transformer circuit [12]

Based on Figure 3 SCT-013-000 Current transformer was used as the current sensor for the monitoring project. The burden resistor was set to 33 Ohm based on the calculation of the sensor current range, the calculation of primary and secondary ratio and lastly to find the load resistance [10].

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11 2.3 Nonintrusive Appliance Load Monitoring

As the price of electrical energy increase, the demand for development of systems monitoring and managing electrical energy consumption also increases. Advanced Metering Infrastructure (AMI) systems designed by energy suppliers do not include detailed analysis of energy consumption by consumers in households. A new method needs to be developed to monitor energy consumption by user. It is an inefficient to use a normal measuring energy consumption meter of each device. Non-Invasive Load Monitoring Systems (NIALMS) offer a possibility to monitor all appliances based on aggregated data from single meter [13]. Main advantages of such systems are:

• simple installation process

• low cost of the installation

• small requirements for modification in existing electrical installations

Every electrical appliance are loads that has their own active power measurements.

There are two types of energy consumption monitoring systems, invasive and non- invasive systems. For invasive system, additional meter is required whereas the noninvasive system only needs a single meter [13]. Figure2.4 show the classification methods for monitoring electrical energy.

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Figure 2.4 Classification of system for monitoring electrical energy [13]

The main aim is to investigate the possibility of identifying electrical appliances based on aggregate measurements from a single meter using NIALMS. In NILM, electrical events can be identified by examining the load signatures such as power, voltage, and current signals obtained from a sensor. The monitoring of appliances is a prerequisite for efficient energy management; this is achieved by providing appliance- level consumption information to consumers [14]. The usage of NILM is shown in Figure 2.5 and Figure 2.6.

Figure 2.5 Non-intrusive appliance load monitoring (NIALM) system [15]

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Figure 2.6 Home appliance load monitoring using NILM [14]

The identification of measurement of appliances with low measurement frequency enables only observation of macroscopic changes of electrical parameters. The changes in active and reactive power (Q) can be analyzed by the algorithm proposed by G. Hart, that consists of the following steps [16]:

• Identification of changes in active power during changes of appliance states

• Clustering of the power changes in the ΔP, ΔQ plane

• Grouping of clusters with opposite signs of change

• Assign of ungrouped clusters to new appliances

• Assign of the grouped clusters to appliances

Some features that can be extracted from voltage and current signals such the current waveform (I), Harmonic (H), active (P) and reactive power (Q), the geometry of V-I curve. These features are used to distinguish the power characteristic of the electric equipment. VI curve was formed from current and voltage values. In the line of the curve axis, horizontal axis declared value of the current and the vertical axis declared voltage values. The signal analyzed and few features can be extracted such as the harmonic active and reactive power. The value of voltage and current signal also helps in identification of

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electrical appliances as shown in Figure 2.7 [17]. The percentage of total harmonic components to fundamental component will yield total harmonic distortion (THD).

Figure 2.7 Voltage- current curve for different electrical appliances [17]

Figure 2.7 shows the curve trajectory for voltage and current formed to different types of electrical equipment. The process of normalization of the values of V and I need to be done so that it can equalize the scale used on each axis V and I. The normalized values of V and I performed by dividing the value of the cycle of V and I with their RMS value.

The power factor and leading current or lagging current vector of the electrical load can be obtained by using the voltage and current graph. This data will help in grouping the type of load nature, which is resistive, capacitive and inductive. Leading current for capacitive load whereas lagging current for inductive load. The shape of the voltage-current curve asymmetry, looping direction, area, curvature of mean line, self- intersection, slope of middle segment, area of segment will show characteristics of load and type of electrical appliances [17].

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2.4 Power Quality Monitor on Harmonic Measurement

The title introduces the current commonly used power quality analyzer, and mainly describes the application steps and points for attention of HIOKI PW3198 power quality analyzer. Based on tests and analysis voltage imbalance and frequency deviation of the company Shanghai Xinsheng semiconductor photovoltaic power generation system are within the allowable range, but there are slight voltage harmonic problems and serious current harmonic problems [18].

Significant harmonic distortion of the shape of the current consumed causes many problems and effects the system. For example, in motor soft starter the excessively consumed reactive power, direct current consumption, current pulses lead to the emergence of additional losses of electrical energy in the elements of the power-supply system, accelerate the aging of insulation of current-carrying parts of equipment and negatively influence its electromagnetic compatibility [19].

Figure 2.8 HIOKI PW3198 power quality analyzer [18]

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Figure 2.8 shows HIOKI PW3198 power quality analyzer. In order to improve the measurement accuracy, it is recommended to preheat for more than 30 minutes, and then zero setting before using it [18].

The test uses HIOKI PW3198 power quality analyzer to test the power quality of the Xinsheng semiconductor photovoltaic power generation system and the low voltage side of the transformer. The harmonic content of the photovoltaic power station should be controlled in the range of the allowable value stipulated in the GB14549-1993 power quality public power grid harmonics. Table 2.1 shows the result of the harmonic test of each monitoring point [18].

Table 2.1 Test results of voltage harmonics [18]

From Table 2.1 the points used in monitoring points of the confluence box (PC) and the Photovoltaic (PV) recirculation box. HRU percentages tells the highest harmonics distortion in this case the investigation on 5th harmonic. The voltage waveforms of PC- 02 and PC-03 points appear more pronounced zigzag based on Figure2.9, while the voltage waveforms of 1# and 5# of PV recirculation boxes are smooth referring to Figure 2.10. There are some voltage harmonics in PC-02 and PC-03 measuring points [18] as the signals are more distorted.

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Figure 2.9 Voltage waveform of monitoring point PC-02 and PC-03 [18]

Figure 2.10 Voltage waveform of recirculation box 1 and 5 [18]

2.5 TFT display configuration

The background of the invention of the TFT LCD display starts with arrangement of thin film transistors (TFTs) each having a polycrystalline semiconductor channel in a substrate for a display device having active elements for example an active matrix display element, a thin film active element substrate or a TFT substrate [20].

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For color LCDs, a color pixel consists of three sub-pixels: red, green, and blue.

When a full-color display is to be performed, the upper 4-bit data of each of R, G, and B video data each having an 8-bit width is used as video data of a TFT type LCD in which a full-color display is to be performed [21]. Figure 8 shows the RGB strip arrangement of pixels on an LCD screen. The light emitted from these three sub-pixels is added to produce the desired color [22]. Each pixel consists of tiny fluorescent lamp that will switch on and off according to the electronic system.

Figure 2.11 Spatial colour synthesis of LCD [22]

Figure 2.12 LCD voltage control light switch [22]

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Figure 2.11 shows that each pixel of an LCD is composed of a liquid crystal (LC) cell, a thin-film transistor (TFT) and a storage capacitor. The liquid crystal cell lies between the TFT substrates and the color filter substrate and rotates to different angles to control the transmittance. The TFT, a switching device, controls the number of electrons flowing into the capacitor, whose electrical field controls the transmittance of the LC cell.

It shows a typical architecture of the LCD controller and panel [22].

2.6 Summary

This chapter provides the information on previous works that are related to this project. These researches are important in understanding the concept of a power analyzer that follows the standard operation with suitable user interface. Many new ideas can be found and the detailed of their work that can be used as a guidance to understand the project more.

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METHODOLOGY

3.1 Introduction

This chapter will cover the methodology part which will be describing the theoretical method and analysis to describe the design and concept of the project. The components that will be used in this project are arduino Mega 2560, TFT LCD Colour Display Screen Module Mega 2560, AC Voltage Sensor Module, and Current Transformer. All the components functionality and operation will be described and explained to create the power analyzer and provide real-time monitoring power consumption.

3.2 Project Methodology

The aim of this research is to design a power analyzer using arduino Mega 2560 as a microcontroller to read and process the data from the current transformer and voltage transformer. C and C++ programming is a fundamental knowledge in the coding of the arduino.

The programmed codes of the arduino is important in calculating all the parameters of the power analyzer such as current, voltage, active power, power factor and harmonic components. When attempting to display the results, it is necessary to acquire the skills to program the arduino and display so that the signal and the parameters can be calculated hence the results can be shown.

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Figure 3.1 is the flow chart for the stages of work for this project. This flow chart includes every step that are required to be accomplished in the implementation of this project. This flow chart can be used as a complete guideline to carry out this project.

Figure 3.1 Flow chart of the project methodology

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The overall process of this flowchart starts with interfacing the SCT-013-000 Current Transformer and ZMPT101B voltage sensor with Arduino Mega 2560. The interfacing of TFT LCD display with the Arduino is important in displaying the parameters of electrical consumptions. The software coding for the parameters of RMS voltage, RMS current, real power, apparent power, power factor and total harmonic distortion (THD) are coded using microcontroller and displayed using the TFT LCD display. The graph of THD was also coded using the microcontroller and displayed using the TFT LCD display.

3.3 Project requirement

In this project SCT-013-000 Current Transformer will be used to get the current measurement of equipment through a wire. It is used to measure the AC current flowing into the electrical appliance. ZMPT101B voltage sensor will be connected to the mains AC supply and TFT LCD displays the results. All the detailed characteristics of the components will be explained further in hardware development. The block diagram of the system is shown in Figure 3.2 while the full connection of the system is shown in Figure 3.3 using Fritzing application.

Figure 3.2 System Block diagram

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The block diagram in Figure3.2 shows the interfacing of Arduino with the voltage and current sensors to calculate all electrical parameters in this project. The TFT LCD display is essential in displaying the data collected also the Total Harmonic Distortion graph.

Figure 3.3 Connection diagram of the proposed system

For Figure 3.3, the connection of the current transformer SCT-013-000 was connected to Analog pin A2 while the voltage transformer ZMPT101B voltage transformer was connected to Analog pin A0. The toggle switch input that will be used for screen switching between power display and THD display connected to PWM input 2. The TFT LCD display can be connected directly to the digital input pins of Arduino Mega 2560.

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24 3.3.1 Hardware development

The main hardware or components used in this project are Arduino Mega 2560, TFT LCD Color Display Screen Module Mega2560, SCT-013-000 Non-Invasive Split Core Current Transformer and ZMPT101B single phase AC voltage sensor.

3.3.1(a) Arduino Mega 2560

Figure 3.4 Arduino Mega 2560 [23]

Arduino Mega2560 is a microcontroller board based on the ATmega2560.

Arduino Mega2560 has 54 digital pins Input / Output, of which 15 pins can be used as PWM outputs, 16 pins as Analog Inputs, and 4 pins as UART (Serial Port Hardware), 16 MHz crystal oscillator, a USB connection, Jack Power, Header ICSP, and a reset button [23]. This is all that is needed to support the microcontroller. For this project the Mega 2560 will be used as a processor and process information to be displayed onto the LCD.

The analog input pins of 0 and 1 will be used for the current transformer and voltage transformer. This is necessary to measure the voltage and current of appliances. The Mega 2560 will processed the collected data into important parameters such as RMS voltage, RMS current, Real Power, Apparent Power, Power Factor and signals Total Harmonic.

The processed data will then be displayed by the TFT LCD Display. User then can view their power usage and consumption directly from the LCD.

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25 3.3.1(b) TFT LCD Colour Display Screen

Figure 3.5 3.8 TFT LCD Colour Display Screen Module Mega2560

TFT-LCD (Thin Film Transistor-Liquid Crystal Display) is commonly used in TV market and small size display [24]. The display used in this project is a 3.8inch TFT module with high resolution, of 480 x 320 pixels. The LCD comes with 36 pins which is suitable for Mega 2560 as the digital ports of this Arduino can be directly inserted with the LCD pins. Most of current TFT-LCD displays use cold cathode fluorescent lamp (CCFL) backlighting thanks to its unrivaled luminance density-emitting the most light within the minimum form factor. [25] The minimum input voltage or VCC for this type of LCD is 3.3 V and it can withstand until up to 5.5 V of DC voltage. If the voltage exceeded the maximum capacity for the LCD it might cause damage to the led pixels as well as to the LCD pins. It is suitable for embedded systems which require display high quality colorful image or video. In this project this LCD display is necessary in displaying the results of power consumed by the loads applied and THD signals.

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26 3.3.1(c) Split Core Current Transformer

Figure 3.6 SCT-013-000 Current transformer

This SCT-013-000 Non-Invasive Split Core Current Transformer AC Current Sensor is used to sense and measure the flow of currents and it is known as current sensors. It is used to measure the alternating current flowing into the electrical appliance.

The current transformer can operate up to 100A maximum current. The maximum current has a turn ratio of 100:0.05. The SCT-013-000 can be used by clipping it to any current carrying wire for example to life wire. It can only be clamped only to a single wire such as life or neutral wire as the current will cancel each other if both life and neutral wire is clamped together. It will then be used to measure the magnitude of current flowing when load is present. Signal conditioning circuit will first be implemented to this current transformer before passing the output through Mega 2560.The circuit is crucial to scale down the voltage to the acceptable range in the analog input of the Mega 2560.

The winding ratio of SCT-013-000 current transformer in this project is 100:0.05.

The secondary coils contain 2000 winding. A burden resistor is required to provide a voltage proportional to the secondary current. This burden resistor value needs to be low enough to avoid current transformer core saturation.

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There are a few calculations needed to obtain the value of the burden resistor.

First, to calculate the peak current flows in the primary winding using this formula below.

Peak to Peak primary current (Ipk−p) :

(𝐼𝑝𝑘−𝑝) = 𝐼𝑟𝑚𝑠 × √2 ……. (3.1)

The value of the 𝐼𝑟𝑚𝑠 will be 100 A.

Peak to Peak secondary current (Ipk−s) : (𝐼𝑝𝑘−𝑠) = 𝐼𝑝𝑘−𝑝

𝑛𝑜 𝑜𝑓 𝑡𝑢𝑟𝑛𝑠 ……. (3.2)

The secondary peak current can be calculated by using Formula 3.2 which the number of turns of this current transformer is 2000 and to calculate the value of resistance need to be used to get an ideal voltage 2.5 V is using the Ohm’s law.

Burden resistor (Rburden) :

(𝑅𝑏𝑢𝑟𝑑𝑒𝑛) = 𝑉𝑖𝑑𝑒𝑎𝑙

𝐼𝑝𝑘 𝑠 ……. (3.3)

With this formula, the ideal value of burden resistance calculated is 35.4 Ω.

Therefore, the value of resistance that will be used is 33 Ω.

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Figure 3.7 Signal Conditioning for Current Transformer using multisim

The current transformer SCT-013-000 (CT) in Figure 3.7 takes alternating AC current directly from the power supply current-carrying wire. As it steps down the alternating current with the ratio of 100:0.05 Amps, the signal conditioning circuit was also used to make sure that the input that will be receive by the Arduino is suitable. The burden resistor was also calculated and was connected in parallel to the secondary current transformer.

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29 3.3.1(d) Voltage Sensor Module

Figure 3.8 AC Voltage Sensor Module C (Single Phase) [26]

The voltage sensor that will be used in this project is ZMPT101B single phase AC voltage sensor. The AC voltage sensor can detect an electric field. Most of the detection can be done by a simple capacitor. This AC Voltage sensor measures line voltage on mains up to 250 V. [26] The ZMPT101B consist of 6 pins that is voltage input (VCC), voltage output (Vout), 2 ground (GND), AC neutral and AC Phase. This sensor has good consistency, for voltage and power measurement. It is also very efficient and accurate in voltage measuring. The input power from home supplied that is approximately 240 Vac will be connected to the phase pins and neutral wire to neutral pins of the ZMPT101B.

The voltage sensor output will then pass the reading of the analog input pins of the Mega 2560. Before passing through the Mega 2560, signal conditioning circuit will first be implemented to this voltage transformer same as current transformer.

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30 3.3.2 Software development

For the software parts of the power analyzer Arduino mostly rely on Mega 2560 that act as a processor activity. The processor needs to receive the data from current transformer and voltage transformer. Both of this data is used as the value of current and voltage that flow into the electrical appliances.

The program that will be used in this project is Arduino IDE that is a software application that will be used to write and upload the codes from the computer to Arduino board. USB port can be used to connect the Arduino board to computer so that we can program the codes and upload it through the Arduino. C and C++ programming is a fundamental knowledge in the coding of the Arduino. The programmed codes of the Arduino is important in calculating all the parameters of the power analyzer such as current, voltage, active power, power factor and harmonic components. The formula of the electrical parameters will be programme in the Arduino and is used in calculating all the data of the power analyzer system. All these formulas are programmed into the Mega 2560 and the Emonlib library will be used for the calculation.

The configuration of the TFT LCD display is quite challenging as suitable libraries needed to be found for the LCD to works. After many trials and errors, the library that the 3.8 TFT LCD Colour Display Screen Module Mega2560 use are Adafruit-GFX- Library-master and MCUFRIEND_kbv. The libraries then were upload into Arduino IDE software and the display was tested. (Refer Figure 3.9 and Figure 3.10)

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Figure 3.9 MCUFRIEND and Adafruit-GFX libraries

Figure 3.10 Testing the TFT LCD display

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According to Figure 3.9, the libraries for the TFT LCD display that was MCUFRIEND and Adafruit-GFX libraries was used and installed using Arduino IDE.

There are other libraries for the specific TFT display that had been tested such as Adafruit TFT and tft.h but none of that is compatible with the TFT display. When testing the TFT LCD in Figure 3.10, the word ‘voltage’ was coded, and the coordinate and size of the word were tested using the codes in IDE.

3.3.3 Data analysis

In this section, the formulas used in calculating all the parameters of the power analyzer system are explained. All these formulas are programmed into the Mega 2560.

Energy monitoring library and Fast Fourier transform library are the two main libraries used in the Arduino coding that make it easier to calculate the parameters of electrical consumption.

3.3.3(a) Calculation of Parameters

The calculation for RMS voltage, RMS current, real power, apparent power, power factor and Total Harmonic Distortion was calculated and coded using the Arduino.

The calculation was explained in detail and the working was shown.

3.3.1.3(a)(i) Calculation for RMS voltage (V)

First, calculate the sum of squared of the input instantaneous voltage 𝑉𝑠𝑢𝑚2 = ∑𝑛𝑖=1𝑉𝑖2……. (3.4)

Where 𝑉𝑠𝑢𝑚2 is the sum of squared voltage and n is the number of samples.

Then, calculate the mean square voltage.

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𝑉𝑚𝑒𝑎𝑛,𝑠𝑞= 𝑉𝑠𝑢𝑚2𝑛 ……. (3.5)

The RMS voltage is then calculated using the following equation 𝑉𝑟𝑚𝑠= √𝑉𝑚𝑒𝑎𝑛,𝑠𝑞……. (3.6)

3.3.1.3(a)(ii) Calculation of RMS current (A)

First, calculate the sum of squared input instantaneous current 𝐼𝑠𝑢𝑚2 = ∑𝑛𝑖=1𝐼𝑖2……. (3.7)

Where 𝐼𝑠𝑢𝑚2 is the sum of squared current and n is the number of samples.

Then, calculate the mean square current.

𝐼𝑚𝑒𝑎𝑛,𝑠𝑞 = 𝐼𝑠𝑢𝑚2

𝑛 ……. (3.8)

The RMS current is then calculated using the following equation 𝐼𝑟𝑚𝑠 = √𝐼𝑚𝑒𝑎𝑛,𝑠𝑞……. (3.9)

3.3.1.3(a)(iii) Calculation of real power (W)

Calculate the instantaneous power from the product of input instantaneous voltage and input instantaneous current.

𝑃𝑖= 𝑉𝑖× 𝐼𝑖……. (3.10)

Then calculate the sum of instantaneous power.

𝑃𝑠𝑢𝑚 = ∑𝑛𝑖=1𝑃𝑖……. (3.11)

Where 𝑃𝑠𝑢𝑚 is the sum of instantaneous power and n is the number of samples.

Then, the real power is then calculated using the following equation.

𝑃 = 𝑃𝑠𝑢𝑚

𝑛 ……. (3.12)

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34 3.3.1.3(a)(iv) Calculation for apparent power (VA)

The apparent power is then calculated using the following equation 𝑆 = 𝑉𝑟𝑚𝑠× 𝐼𝑟𝑚𝑠……. (3.13)

3.3.1.3(a)(v) Calculation for power factor

The power factor is calculated using the following equation 𝑃𝑓 = 𝑃

𝑆……. (3.14)

3.3.1.3(a)(vi) Calculation for Total Harmonic Distortion

To measure the wave shape distortion, we use the quantity of the Total Harmonic Distortion, THD. The THD is calculated by sampling the input signal of the voltage transformer using FFT.

A period function with the T period is defined by

𝑓(𝑡) = 𝑓(𝑡 + 𝑇) ……. (3.15)

The periodic function represented by Fourier series:

𝑓(𝑡) = 𝐴0+ ∑𝑣=1𝐵𝑣. 𝑠𝑖𝑛(𝑣𝑤𝑡) + 𝐶𝑣. 𝑐𝑜𝑠 (𝑣𝑤𝑡) ……. (3.16)

A0 is the amplitude of DC components. For AC voltage waveform, A0 is zero.

The amplitude for each harmonic can be computed from:

𝐴𝑣 = √ 𝐵𝑣2+ 𝐶𝑣2……. (3.17)

THD is the ratio of the power of harmonic components to the power of fundamental frequency. For voltage distortion the sum of the RMS of the harmonic components, 𝑉𝑛 and the RMS of the fundamental frequency, 𝑉1 must be find.

(𝑇𝐻𝐷) =

√∑ 𝑉𝑛 𝑛_𝑟𝑚𝑠2

𝑉𝑓𝑢𝑛𝑑_𝑟𝑚𝑠……. (3.18)

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35 3.4 Project Design and testing

The accuracy of the power analyzer was tested by using a Fluke Power Quality Analyzer. A Fluke Power Quality Analyzer (refer Figure 3.11) is a portable measuring equipment that can measure various electrical parameters such as Current (AC and DC), Voltage (AC and DC), Active power, Reactive Power, power factor and much more. First, the selected electrical equipment’s current and voltage will be measured with the Fluke Power Quality Analyzer. Then the power analyzer device will be used to measure the voltage and current of the appliances. The appliances that will be used in this project are hairdryer and electric kettle. The data of both results will then be compared to test the accuracy of the power analyzer device.

Figure 3.11 Fluke Power Quality Analyzer

For total harmonic distortion, the results of Fluke Power Quality Analyzer and the power analyzer will be compared. Only the voltage signal will be compared. The Fluke Power Quality Analyzer voltage probes will be directly connected to the AC mains of life and neutral current conducting wire. By referring to Figure 3.12, the Fluke Power Quality Analyzer already has the function for THD calculation and THD signal plotter so the results will then be compared with the power analyzer.

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Figure 3.12 THD of voltage settings on Fluke Power Quality Analyzer

3.5 Summary

In chapter 3, the methodology of this project is discussed by explaining the hardware and software of used in this project. The hardware part that is the Arduino Mega 2560, current transformer, voltage transformer and display was explained. The software part that consist of Arduino and TFT LCD display programming was also discussed.

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RESULTS AND DISCUSSION

4.1 Introduction

The results and discussion of the project will be presented in this chapter. The data taken from experiment and testing of the power analyzer will be showed and explained.

4.2 Signal Conditioning Circuit

Signal conditioning circuit of the power analyzer will first be tested using the oscilloscope to make sure that output signals of the transformer was scaled down to a suitable voltage range for the Arduino analogue port input voltage range. The signal conditioning circuit was fabricated on a PCB.

Figure 4.1 shows the signal conditioning circuit that is used in current transformer.

The circuit contains the burden resistor that is 33 Ohm connected directly to the secondary point of the current transformer. A two 10 kilo Ohm resistors and a 10 uF capacitor are used as a DC offset to shift the signal to the positive side.

Figure 4.1 Signal conditioning circuit for Current Transformer

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4.2.1 Voltage Transformer Signal Conditioning

ZMPT101B voltage sensors used in this project can be connected directly to the AC power supply. Signal conditioning for this sensor is not needed as the sensor ZMPT101B contains built in voltage divider and a DC offset to make sure that the signal voltage is above the axis that is above 0V. A DC bias of the signal is added into the circuit sensor so that the signal contain only positive portion. Figure 4.1 shows the oscilloscope reading for voltage signal of the sensor. The signal will then be used as a sample to calculate the THD of voltage using FFT.

Figure 4.2 Input waveform of the Voltage transformer

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39 4.2.2 Current Transformer Signal Circuit

The current signal was obtained from the split core current transformer and was tested with a load that is using a hair dryer. The output of the current transformer before applying the DC bias consist of negative part and positive part. The signal will then be turned into voltage by a burden resistor. Figure 4.2 shows the input waveform of the current transformer before applying DC bias.

Figure 4.3 Input waveform of Current transformer before DC bias

The current acquisition part was tested with the DC bias circuit. The oscilloscope reading for waveform of input current signal after DC bias was shown in Figure 4.3. The value of peak to peak current and frequency remains unchanged. It was noticed that the waveform of the signal was like the DC bias except it was shifted to a level of about 2.5V.

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Figure 4.4 Input waveform of Current transformer after applying DC bias

4.3 Experiment on The Developed Power Analyzer Device

The power analyzer energy device was calibrated in the Arduino code before using it to measure any electrical appliances. The calibration is made by comparing the results gained from Fluke Power Quality Analyzer in the Power Lab with the data obtain from the power analyzer. The parameters are set in order to calibrate the value of RMS voltage, RMS current and phase which are VOL_CAL and CUR_CAL respectively. The calibration for the power analyzer was done by changing the calibrated value of voltage and current in Figure 4.5 using the emon library in Arduino IDE application.

Figure 4.5 Calibration voltage and current using emon library

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The calibration process for voltage was done by inserting test leads of Fluke Power Quality Analyzer and power analyzer plug into the sockets of the extension. The calibration process for current was done by clipping the current probe of Fluke Power Quality Analyzer and the split-core current transformer to the same current carrying wire of the extension socket.

The value of voltage and current of the power analyzer device were adjusted close to the values of Fluke Power Quality Analyzer and the process is done in the laboratory.

4.3.1 Performance testing of the Power Analyzer

The test was conducted to measure the accuracy of the power analyzer to measure the following electrical parameters RMS current, RMS voltage, real power (P), apparent power (S), power factor (PF) and total harmonic distortion (THD) of the electrical appliances. The test was carried out by clipping the current probe of Fluke Power Quality Analyzer and current transformer to the current carrying wire of the extension. The voltage sensor was also plugged in to the extension as well as the voltage probe of the Fluke Power Quality Analyzer.

4.3.1(a) Test Results Using Hairdryer

The hairdryer used in this experiment was Hair Dryer JY-5048 1600W that consist of 3 modes of operations on temperature. The operations that were tested in this experiment were off, low speed, and full speed.

Table 4.1 below shows the results that had been taken from the developed power analyzer and the Fluke Power Quality Analyzer. Figure 4.4 shows the results during OFF

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mode hairdryer while Figure 4.5 and Figure 4.6 shows the results during Low Speed mode and Full speed mode of the hair dryer respectively.

Table 4.1 Results of Power Analyzer and Fluke Analyzer using Hair Dryer

Power Factor ApparentPower (kVA) Real Power(kW) RMS Current(A) RMS Voltage(V) Mode Equipment

0.20 0.09 0.06 0.10 0.62 0 (off) PowerAnalyzer

1.00 0.00 0.00 0.02 0.33 Fluke

80 0 0 80 46.77 Error (%)

0.8 0.186 0.157 0.76 244.28 1 (low speed) PowerAnalyzer

0.9 0.18 0.16 0.72 246.5 Fluke

10 3.22 1.87 5.26 0.9 Error (%)

0.9 0.66 0.60 2.69 244.89 2 (full speed) PowerAnalyzer

0.95 0.67 0.66 2.74 245.30 Fluke

5.26 1.49 9.09 1.82 0.17 Error (%)

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Figure 4.6 Hair Dryer Operation (OFF mode)

Figure 4.7 Hair Dryer Operation (Low Speed mode)

Figure 4.8 Hair Dryer Operation (High Speed mode)

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44 4.3.1(b) Test Results Using Electric Kettle

Another result was obtained using an electric kettle to test the power parameters using the power analyzer and the Fluke Power Quality Analyzer. The result is tabulated in Table 4.2 below and Figure 4.9 shows the results of power analyzer and Fluke Power Quality Analyzer during the experiment.

Table 4.2 Results of Power Analyzer and Fluke Analyzer using Electric Kettle

Figure 4.9 Results of Electric Kettle

Equipment Power

Analyzer

Fluke Error (%)

RMS Voltage (V) 243.36 241.5 0.77

RMS Current (A) 8.70 8.95 2.79

Real Power (kW) 2.03 2.10 3.33

Apparent Power (kVA) 2.17 2.20 1.36

Power Factor 0.92 0.98 6.12

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4.3.1(c) Test Results of Total Harmonic Distortion on Voltage

The result of Total Harmonic Distortion was obtained by the power analyzer and the Fluke Power Quality Analyzer and the data are tabulated in Table 4.3. Figure 4.8 shows the experiment conducted to find the Total Harmonic Distortion of Voltage using the two devices. As the hairdryer and the electric kettle does not actually make the difference in voltage drop the test only requires the connection of the probes of Fluke Power Quality Analyzer to the mains supply voltage. For the power analyzer the voltage output signal from the voltage sensor is used as a sampled signal to calculate the total harmonic distortion.

Table 4.3 Test Results of Total Harmonic Distortion on Voltage

Equipment Power

Analyzer

Fluke Error (%)

THD (%) 1.93 1.30 32.64

Figure 4.10 Total Harmonic Distortion Experiment

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46 4.3.1(d) Discussion on the test results

This section explains the causes and effect based on the results obtained during the experiment and testing. Based on the results tabulated in Table 4.1 and 4.2, it was noticed that there were some differences between the actual result obtained from the Fluke Power Quality Analyzer and the results obtained through the developed power analyzer.

The differences were caused by the tolerances in the signal conditioning circuit of current sensors and the voltage sensor.

This condition of the DC bias shifting to the actual level of 2.5 V might lead to this difference in reading. The accuracy of shifting voltage was also caused by the ZMPT101B voltage sensor tolerance that causes by the cut off in the output signal of the voltage and prevent it from achieving the actual level of 2.5 V.

For the total harmonic distortion results the error when comparing the Fluke Power Quality Analyzer and power analyzer are caused by the differences in refresh rate of the power analyzer. Calculating and processing the codes for FFT might take a while and the process is slow compared to the refresh rate of Fluke Power Quality Analyzer which is very high. Thus, the slow refresh rate might be the main cause for the error.

The power factor was improved at full speed operation compared at low speed operation mode. The hair dryer operated at low speed mode require more reactive power since the motor is made up of inductive load. The heating element did not consume high real power to generate heat resulting in the reactive power consumed by the inductive load was higher at low speed operation mode and thus causing lower power factor.

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47 4.3.1(e) Total Harmonic Distortion Discussion

Total Harmonic Distortion (THD) is a measurement value that shows the distortion of voltage signal. THD is an important factor especially in power system and audio equipment. Harmonic can cause the quality of power supply network to deteriorate causing effects such as: high reactive power, low power factor, high values of harmonic currents and harmonic voltages, sometimes even unbalance between phases in high power loads [27].

During the experiment two harmonic samples from the ZMPT101B voltage sensor was taken and analyze. The data from the signal in the form of sine wave function was sampled and analyzed using FFT functions in Arduino. The number of samples taken was set to 128 samples and the sampling frequency was set to 800 Hz. Since the fundamental frequency of the electrical supply in Malaysia is 50 Hz, it means that the number of harmonics that can be read by the power analyzer is until the 8th harmonics.

The two sets of data were taken in different condition where THD is equal to 2.24% and 11.6%. The sample data and the computed magnitude were plotted using Microsoft Excel. The THD display of the power analyzer was also shown in Figure 4.11 and Figure 4.14.

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Figure 4.11 The Sampled Input Voltage Data When THD = 2.24%

Figure 4.12 Computed Magnitude of the Harmonic Components when THD = 2.24%

-1.5 -1 -0.5 0 0.5 1 1.5

0 0.00625 0.0125 0.01875 0.025 0.03125 0.0375 0.04375 0.05 0.05625 0.0625 0.06875 0.075 0.08125 0.0875 0.09375 0.1 0.10625 0.1125 0.11875 0.125 0.13125 0.1375 0.14375 0.15 0.15625

THD = 2.24%

0 5 10 15 20 25 30 35 40 45

0 18.75 37.5 56.25 75 93.75 112.5 131.25 150 168.75 187.5 206.25 225 243.75 262.5 281.25 300 318.75 337.5 356.25 375 393.75

THD = 2.24%

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