IN THE NAME OF ALMIGHTY ALLAH, THE MOST BENEFICIAL AND THE MOST MERCIFUL

REAL TIME MONITRORING AND SUPERVISORY CONTROL OF DISTRIBUTION SYSTEM BASED ON GENERIC LOAD

ALLOCATION: A SMART GRID SOLUTION

By

Name Roll No

1) Zain Anwer Memon (G.L) 09ES012) Riaz Rasool Aamir (A.G.L) 09ES1033) Irshad Raheem Memon 09ES1064) Muhammad Ilyas Memon 09ES113

Supervised by:Dr. Bhawani Shankar Chowdhry

Co-Supervised by:Engr. Irfan Ahmed Halepoto

Department of Electronics EngineeringMehran University of Engineering & Technology, Jamshoro

Submitted in partial fulfillment of the requirement for the Degree of Bachelor of Electronics Engineering

February 2013

DEDICATION

THIS HUMBLE EFFORT IS DEDICATED TO

OUR BELOVED PARENTS WHO WERE

ALWAYS THERE TO SUPPORT US

WHENEVER WE NEEDED

ENCOURAGEMENT. THEIR EFFORTS

HAVE UPLIFTED, ENCOURAGED,

INSPIRED AND GUIDED US TO THE

PEAK OF OUR SUCCESS

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CERTIFICATE

This is to certify that Project/Thesis Report on “REAL TIME MONITRORING AND SUPERVISORY CONTROL OF DISTRIBUTION SYSTEM BASED ON GENERIC LOAD ALLOCATION: A SMART GRID SOLUTION” is submitted in partial fulfillment of the requirement for the degree of Bachelor of Electronic Engineering by the following students:

Name of Students Roll Nos.

1. Zain Anwer Memon (G.L) 09ES01

2. Riaz Rasool Aamir (A.G.L) 09ES103

3. Irshad Raheem Memon 09ES106

4. Muhammad Ilyas Memon 09ES113

_________________Dr. Bhawani Shankar Chowdhry

Project/Thesis Supervisor

__________________Dr Wajiha Shah

ChairpersonDepartment of Electronic Engineering

Dated: ______________

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ACKNOWLEDGEMENT

With deep and profound gratitude and thanks to “ALMIGHTY ALLAH” for HIS so kindly conferring us the opportunity of undertaking and completing this project with the right approach and complete success. All praises be to Allah, the Most Gracious and the most Merciful, for all the blessings that He has given us, especially in completing this project.

The most beautiful and loving, our parents, we owe them very much for their sincere prayers, encouragement, cooperation and support in boosting our morals.

Said a wise man:

“Almost anything can be accomplished if you don’t care

Who gets the credit? When all is said and done, there remain

Many people un-thanked, un-honored and unsung”

We are like especially thankful to the support and assistance of our project supervisor and as Dean of FEECE Dr.B.S Chowdhry for his helpful suggestions, supervision and guidance and our co-supervisor Engr.Irfan Ahmed Halepoto. Our chairperson Dr.Wajiha Shah for the allocation of labs, PC and other facilities for the accomplishment of our Final year project. Our Labs staff for their cooperation during the working hours.

Finally, we are thankful to our beloved class fellows and lab assistants who have been source of encouragement and support throughout project.

We, the group members would like to avail this opportunity to show gratitude to all those who came up with the valuable guidance and moral support.

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ABSTRACTEnergy (power) is very much important nowadays. Almost every equipment uses

electrical power. Almost every work in daily life is performed by machines or it can be said that men are now dependent on machines. So power is the main parameter that really needs to be managed. The Electrical power that is generated must meet the demand so that there is no any power shortage, but here in Pakistan the main thing is that power is not generated much that is required, also neither it is managed nor there is any check and balance of the use of power. There are many steps that can be taken to overcome power shortage. The general opinion is that the generation be increased; others say distributions should be improved, but firstly there must be check and balance that how much power is used by each of the consumer connected with substation so that the load should be forecasted and accordingly power be generated. So we are presenting one solution regarding distribution and load allocation to each customer that if the customer uses power greater than the load allocated, further power is not provided and consequently that appliance is not turned on unless the total load must not be decreased.

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TABLE OF CONTENTS

CERTIFICATE…………………………………………………………… iii

ACKNOWLEDGEMENT……………………………………………….. iv

ABSTRACT……………………………………………………………….. v

LIST OF TABLES………………………………………………………… x

LIST OF FIGURES……………………………………………………….. xi

LIST OF ABBREVIATION……………………………………………… xii

CHAPTER 1 INTRODUCTION 1-2

1.1 Background 1

1.2 Smart Grid Solution 1

1.3 Aims and Objectives 1-2

1.4 Summary 2

CHAPTER 2 POWER SYSTEM SCENARIO IN PAKISTAN 3-5

2.1 Electrical Network 3

2.2 Electricity Sector in Pakistan 4

2.2.1 Priorities and Principles of Load Shedding 4

2.2.2 Losses 5

CHAPTER 3 LOAD PROFILE AND MANAGEMENT 6-16

3.1 Load profile 6

3.1.1 Methodology 6

3.1.2 Primary Data Sources 6

2.3.2.1 Demographic information 6

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3.1.2.2 Daily occupancy information 6

3.1.3 Generating the Load Profile 6

3.1.3.1 An Area of Study 6

3.1.3.2 Household Type Allocation 7

3.1.3.3 Time of Use Probabilities Profiles 7

3.1.4 Load Profile and Forecast 7

3.2 Demand Side Management 7

3.2.1 Electricity Crisis and Demand Side Management 8

3.2.2 Causes Of Crisis 8

3.2.3 Solution to the Crisis: Demand Side Management 9

3.2.4 Load Forecast and DSM 9

3.3 Power Monitoring 9

3.3 1 What is power system monitoring? 9

3.3.2 Why to install a power monitoring system? 10

3.3.2.1 Environmental 10

3.3.2.2 Reliability 10

3.3.2.3 Maintenance 10

3.3.2.4 Safety 10

3.3.2.5 Financial 10

3.3.3 Real time remote power monitoring system 11

3.3.3.1 SCADA 11

3.3.3.1.1 SCADA Features 11

3.3.3.1.2 SCADA 12Subsystems

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3.3.3.1.3 SCADA system 15Operation

3.4 A Proposed model 16

CHAPTER 4 HARDWARE AND IMPLEMENTATION 17-33

4.1 Block diagram 17

4.2 Flow Chart 18

4.3 Hardware Components 19

4.3.1 Arduino UNO Development Board 19

4.3.1.1 Overview 19

4.3.1.2 Features 19

4.3.1.3 Power 20

4.3.1.4 Memory 21

4.3.1.5 Input and Output 21

4.3.1.6 Communications 22

4.3.1.7 Programming 22

4.3.1.8 Automatic(Software) Reset 22-23

4.3.1.9 USB Over Current Protection 23

4.3.1.10 Physical Characteristics and 23 Shield Commpatibility

4.3.1.11 Pin Mappings of the Board 23-24 With Microcontroller(Atmega328)

4.2.2 ULN2003 IC 24-25

4.2.3 Liquid Crysal Display 25-26

4.2.3.1 Pin Description 26

4.2.4 Voltage Transformer 27

4.2.5 Current Transformer 28-29

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4.2.6 Diode Bridge 29

4.2.7 LM7805 Regulator IC 29-30

4.4 Implementation 30-32

4.4.1 ADC Reading 32-33

4.5 Result 33

CHAPTER 5 SOFTWARE AND SIMULATION 34-40

5.1 Proteus Simulator 34-35

5.2 Current and Voltage Measuring Circuit 35-36

5.3 Programming 37-40

CHAPTER 6 CONCLUSION/FUTURE WORK 41

6.1 Conclusion 41

6.2 Future Work 41

REFERENCES 42

ix

x

LIST OF TABLES

Table 4.1: Arduino and Atmega328 Pin Mapping 24

Table 4.2 LCD Pin Description 26

xi

LIST OF FIGURESFig 2.1 An Electric Network Block Diagram 3

Fig 2.2 Power Sectors In Pakistan 4

Fig 3.1 A SCADA RTU system 14

Fig 3.2 SCADA system Operation 15

Fig 4.1 Block diagram of project 17

Fig 4.2 Flow Chart of System 18

Fig 4.3 Arduino UNO Development Board 19

Fig 4.4 ULN2003 IC Internal Connection 25

Fig 4.5 Pin Configuration LCD 26

Fig 4.6 Transformer 28

Fig 4.7: Current Transformer 29

Fig 4.8 Diode Bridge Full Wave rectifier 29

Fig 4.9 LM7805 IC 30

Fig 4.10 Project Test Hardware in Breadboard 30

Fig 4.11 Real Implemented System 31

Fig 4.12 PCB Relay Interfacing Circuit 32

Fig 5.1 Schematics of the Microcontroller Circuit 33

Fig 5.2 Schematic of the Relay Interfacing Circuit 34

Fig 5.3 PCB Layout of Relay Interfacing Circuit 35

Fig 5.4: Current and Voltage Measuring Circuit 35

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LIST OF ABBREVIATIONSLCD = Liquid Crystal Display

LED = Light Emitting Diode

CT = Current Transfomer

VT = Voltage Transfomer

SCADA= Supervisory Control and Data Acquisition

HMI = Human Machine Interface

RTU = Remote Terminal Unit

PLC = Programmable Logic Controller

KESC = Karachi Electric Supply Company

WAPDA = Water and Development Authority

PEPCO = Pakistan Electric Power Company

LESCO = Lahore Electric Supply Company

GEPCO = Gujranwala Electric Supply Company

FESCO = Faisalabad Electricity Supply Company

IESCO = Islamabad Electricity Supply Company

MEPCO = Manpower Export Placement Corporation

PESCO = Peshawar Electric Supply Company

HESCO = Hyderabad Electric Supply Company

QESCO = Quetta Electric Supply Company

TESCO = Tribal Electric Supply Company

SEPCO = Southern Electric Power Company

GENCO = Central Power Generation Company

NTDC = National Transmission & Despatch Company

DISCO = Power Distribution Company

JPCL = Jamshoro power Company Limited

CPGCL = Central Power Generation Company Limited

NPGCL = Northern Power Generation Company Limited

LPGCL = Lakhra Power Generation Company Limited

AC=Alternating Current

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CHAPTER 1

INTRODUCTION

1.1 Background:

The electrical power system in Pakistan is unpredictable, the power that is generated at the Power Stations doesn’t meet the power requirement for the consumers, mostly power shortage occurs whether it is winter or summer. We can’t forecast how much power the consumer will use a day due to lack of power monitoring and mismanagement. Let suppose the Power Company allocates a particular amount of power to each user and therefore generates the power as required by the particular area, but there is no any limit for any consumer that how much that consumer uses the power per day. There is no any check and balance for power usage in any area. And almost all the consumers use power more than they are allocated, resulting power shortage, load shedding and overloading of distribution transformers. This causes failure of distribution transformers which becomes very costly. Hence the power generation company cannot generate the required amount of power for the consumers. Hence firstly we need to monitor and forecast the power so as we come to know the power usage limit for any area. And here we provide one solution regarding power use limitation at consumer side. We have designed a controller that will limit the consumer not to use the power more than allocated.

1.2 Smart Grid Solution:

“A smart grid is a modern electricity system. It uses sensors, monitoring, communications, automation and computers to improve the flexibility, security, reliability, efficiency, and safety of the electricity system.”[1]In terms of our project smart grid is an automated, widely distributed energy delivery network; the Smart Grid is characterized by a two-way of electricity and information and will be capable of monitoring everything from power plants to customer preferences to individual appliances. Smart grid takes in account the benefits of distributed computing and communications to deliver real-time information and enable the near-instantaneous balance of supply and demand at the device level. So here we present one part of smart grid employed at consumer side to limit users to allocated power usage.

1.3 Aims and Objectives:

The main objective of this project is to limit the user for a particular load, by controlling the power at the service main before the energy meter. Here we place two transformers for measuring the line current and voltage, and when any device is turned

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on, its power is measured with the help of two more voltage and current transformers. The microcontroller measures the power in the main line and if the main line is on full load, no any device relays are energized and hence no device turns on unless the main line power is reduced than the maximum power.

The programming is done in C language, and the microcontroller used is Atmega328, mounted on Arduino UNO development board.

1.4 Summary:

We studied the power system that is currently employed in Pakistan and the main thing that we observed is that there is nothing monitored on the consumer side, we are just generating the power and transmitting and distributing to the user without knowing how much the consumer will use the power. Hence we started our work on this project. The hardware, software, simulation, implementation are given in further chapters.

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CHAPTER NO: 02

POWER SYSTEM SCENARIO IN PAKISTAN

This project is based on the power generation and distribution of load, load forecasting and load limiting. So the electrical system is described below:

2.1 Electrical Network:

Electrical networks provide the energy to the end customers according to the supply and demand. The power is generated at grid via different sources i-e Hydroelectric, Gas/Coal, Fired Steam and Nuclear. Using step up Transformers, the power is further transferred to the transmission network which is interconnected at switching stations and substation to form a network of lines called power grid. The power received is step downed and feed to the distribution and consumed by the users as shown in fig 2.1.

Fig 2.1 An Electric Network Block Diagram[2]

3

POWER SECTOR

KESC WAPDA

4 GENCOs

JPCLCPGCLNPGCLLPGCL

10 DISCOs

PESCOGESCOHESCOIESCOLESCO

MEPCOFESCO

QUESCOTESCOSEPCO

1 TransCO(NTDC)

2.2 Electricity Sector in Pakistan:

There are two main utilities (sectors) that is KESC(Karachi Electric Supply Company) which served in Karachi areas and other one is WAPDA(Water and Power Development) which serve the rest of the country. WAPDA is sub-divided into 4 GENCOs, 10 DISCOs, and one TransCO (NTDC) as shown in fig 2.2.

Fig 2.2 Power Sectors In Pakistan[3]

2.2.1 Priorities and Principles of Load Shedding:

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A distribution company shall have plans and schedules available to shed up to 30 % of its connected load at any time upon instruction from NTDC. This 30 % load must be made up from separate blocks of switchable load, which can be disconnected in turn at the instruction from NTDC. A distribution company shall provide its copies of these plans to NTDC. Wherever possible NTDC shall give distribution companies advance warning of impending need for load shedding to maintain system voltage and/or frequency in accordance with the Grid Code. As per provisions of the Grid code, NTDC shall maintain an overview and as required instruct each distribution company the quantum of load to be disconnected and the time of such disconnection. The instruction shall be given in clear, unambiguous terms and related to prepared plans. When instructed by NTDC, the distribution companies shall shed the load in the following order namely;

(a) Supply to consumer in rural areas; and residential consumers in urban areas where separate feeders exist.

(b) Supply to consumers, other than industrial, in urban areas.(c) Supply to agriculture consumers where there is a dedicated power supply.(d) Supply to industrial consumers(e) Supply to schools and hospitals(f) Supply to defense and strategic installations.

A distribution company shall prepare schedules of load disconnection, which demonstrate this priority order and which rotate load disconnections within the above groups in a non-discriminatory manner. The principle of proportionality shall be kept so as not to excessively burden a particular consumer class.

2.2.2 Losses:Losses are estimated from the discrepancy between energy produced and energy

sold to end customers, Transmitting electricity at high voltage reduces the fraction of energy lost to resistance.

The safe and reliable transmission and distribution of electricity remain a major problem in Pakistan. Losses running into billions of rupees due to power theft during transmission & distribution and billing inefficiencies. Utilities face losses due to unmetered and unaccounted sales. The need of the hour is to devise a utility-wise turnaround plan and monitor its implementation at the highest level in order to reduce aggregate technical and commercial losses.

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CHAPTER 3

LOAD PROFILE AND MANAGEMENT

3.1 Load profile:

In the Pakistan the domestic sector accounts for almost one third of the total electricity consumption. It contributes the largest peak demand, particularly in the winter season, which has consequences on the power Infrastructure [4] .Traditional forecasting methods look at national energy profiles based on historic trends and thereby determining the infrastructure requirements. Recently, energy saving methods, and embedded energy supplies via renewable or combined heat and power, make it possible for local communities to modify their behavior.

3.1.1 Methodology:

The identification of the pattern of energy uses of a house and the prediction domestic load profile is an essential in order to match load shape to the power generated, and also to predict the possible impact of any energy management action directly on the daily load profile. The electrical load profile is based on assumptions as to the type of electric devices including appliances and lighting, and their usage. Different households have different lifestyles, which mean the shape of the total. Load profile will fluctuate from house to house, and from day to day.

3.1.2 Primary Data Sources:

The inputs of the electricity demand profile generator being presented as follow:

3.1.2.1 Demographic information: The information on the type of households is required such as the number of

adults, working people, and number of children present in house. Because the households with children use more energy as compared to the households having no children.

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3.1.2.2 Daily occupancy information: This is the behavior of occupants in households with respect to their usage of

appliances and lighting on a daily basis. How much time the occupants use the appliances and for what time the appliances are turned off and not in use.

3.1.3 Generating the Load Profile:For generating load profile, following points should be considered:

3.1.3.1 An Area of Study:For generating the load profile we will have to take the data from community of

households for that area. The data will be noted and observed for generating load profile for that area and consequently load forecasting would be done.3.1.3.2 Household Type Allocation:

To get a picture of the demographic characteristics of the area in order to allocate different numbers of households, calculation should be based on the percentage share of the power allocation of households. The physical location of the households is allocated randomly using Excel’s rand function.

3.1.3.3 Time of Use Probabilities Profiles:For generating load profile, the probability of usage times per day for devices of

each single household should be considered. In other words the behavior must be predicted on the basis of particular community. For lighting, the winter and summer aspects should better be considered in the modeling. For other appliances the assumption is that the behavior may be the same.

3.1.4 Load Profile and Forecast:Analyzing annual hourly load profiles is an important aspect of generation

planning to capture the hourly and seasonal variation in the load. The hourly loads are used to construct the monthly load duration curves which are one of the key inputs to generation planning. The historical monthly load duration curves are used for planning the future years. The assumption is that the future monthly/seasonal load variations would be very similar to the past ones. However, the historical load duration curves in the recent years for PEPCO system cannot be directly used for future years since these curves are restricted by supply availability. Therefore it is necessary to have information on unrestricted monthly load patterns and hourly load profiles to represent the future years.

The load forecast is the first step for a power system master plan study. The forecast is based on multiple regression techniques using historical data for regression variables like electricity consumption by different categories, electricity tariffs, GDP for different sectors, Consumer Price Index CPI, population of the country, number of customers for different electricity tariff categories, etc[5]. The forecast presents three scenarios low, normal and high and a scenario where the normal forecast is adjusted for demand side management (DSM) measures.

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3.2 Demand Side Management:

Demand-Side load Management (DSM) is a set of methods that co-ordinate the activities of energy consumers and energy providers in order to realize the best adaptation of energy production capabilities for consumer needs[6]. DSM has two perspectives on the one hand, it has negative environmental impacts and on the other hand, it decreases the cost of energy production. The basic kinds of DSM control are direct control that shifts power requests by directly interrupting the high power consuming appliances and Local control that consists in setting up a policy which encourages consumption at off-peak periods by reducing energy costs.

The DSM control allows energy providers to charge users for the actual energy production cost in a more precise way. It also allows users to adjust their power consumption according to energy price variations. In the peak period, the domestic customer would be able to decide whether to wait and save money or to use appliances. This strategy is more reactive than the basic DSM control but more complex to control when comfort has to be taken into account. Energy management can be formulated as a scheduling problem where energy is considered as a resource shared by appliances, and periods of energy consumption are considered as tasks. DSM involves the planning and implementation of utility activities design to influence the time pattern and amount of electricity demand in ways that will increase customer satisfaction, and coincidentally produce desired changes in the utilitie’s system, load shape several factors used to assess the load desirability of specific load shape changes, including impact on system cost and reliability. It also includes load management identification and promotion of new uses, strategic conservations, electrification, retention, customer generation and adjustment.[6]

3.2.1 Electricity Crisis and Demand Side Management:The electricity in Pakistan is presently facing a serious energy crisis. Despite

strong economic growth during the past decade and consequent rising demand for energy, no worthwhile steps have been taken to install new capacity for generation of the required energy sources. Now, the demand exceeds supply and hence load-shedding is a common phenomenon through frequent power shutdowns. Pakistan needs about 14000-15000MW electricity per day, and the demand is likely to rise to approximately 20,000 MW per day by 2010. Presently, it can produce about 11, 500 MW per day and thus there is a shortfall of about 3000-4000MW per day. This shortage is badly affecting industry, commerce and daily life of people. The demand in the electrical energy demands in a country is proportional to the growth in the population. If this demand is not met with the supply, energy crisis is produced. Pakistan has been facing an unprecedented energy crisis since last many years. This problem becomes more severe in summer and as a result shortage of electricity is faced 8 to 10 hours in urban areas while 16 to 18 hours in rural areas. All possible measures need to be adopted, i.e., to conserve energy at all levels, and use all available sources to enhance production of energy. It seems that the government is considering importing energy from Iran and Central Asian Republics and using indigenous sources, such as, hydel, coal, waste, wind, and solar power, as well as other alternate and renewable energy sources, besides nuclear power plants for production of energy.

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3.2.2 Causes Of Crisis:The major management related causes of the crisis are[7]:

1. Faulty management information system2. Failure of forecast and future planning3. No new transmission / distribution networks and grid stations4. Failure to set up new generating stations in time.5. Unexpectedly rapid growth of load.

The problem is compounded when corrupt officials sell electricity illegally on the black market. For instance, power theft amounts to $300 million and Up to 40 percent of the electricity vanishes as it passes through the industrial districts. People living in the wealthier districts tap another 10-15 percent to run their air conditioners. Such problems caused 350 million people to suffer prolonged blackouts.

3.2.3 Solution to the Crisis: Demand Side ManagementDSM is a crucial element in planning to meet the load. Such programs should be

fostered and their results taken into account as programs are implemented. NTDC has the target to improve the load factor by employing the DSM techniques and by promoting the Industrial share in the composition of system load. It is expected that the load factor of the system shall improve to 71% provided the proposed DSM measures are implemented.

3.2.4 Load Forecast and DSM:Load forecasting entails the prediction of the future level of demand, and provides

the basis for future supply side and demand side planning. Generation planning requires a load forecast for the country as a whole, while transmission and distribution planning requires more load–level and geographic detail to determine the location, timing and loading of individual lines, substations and transformation facilities. Geographic load detail is also a factor in the determination of the location of generation plants since it is generally desirable to locate generation sources close to the load centers.

3.3 Power Monitoring:In order to understand load profile of system we will go through general concept

regarding power monitoring system. In which we will discuss two main facts that are given below.

1. What is power monitoring system? 2. Why power monitoring is required?

3.3 1 What is power system monitoring?In a changing electric industry, monitoring power supply and power quality are

critical to ensuring optimal performance of power systems. Monitoring can provide information about power flow and demand, as well as the quality of the power. Monitoring can be a vital diagnostic tool, identifying problem conditions on a power system before they can cause disturbances or interruptions. The concept of power quality

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monitoring is related with the detection of voltage events in the mains network. The characterization of these voltage events results from standards that define several limits for their amplitudes, duration and maximum number of occurrences within a time period. In the last three decades, the loads connected to the mains network suffered great changes. The number of Electronic and sensitive equipment increased considerably, and the old concepts of monitoring are not representative for these loads. The economical impact in industrial environment as a consequence of an electrical failure, introduces the study of power quality, and power quality monitoring.

3.3.2 Why to install a power monitoring system?

There are many benefits to installing a power monitoring system. Some of which strongly interrelate with each other. A properly designed and installed monitoring system offers a deeper understanding of the operational parameters of the facility's electrical system. A close appraisal of the data generated by a monitoring system can reveal a variety of overt and subtle opportunities, including:3.3.2.1 Environmental:

A better knowledge of how energy is used within a facility allows you to identify an array of prospects to improve efficiency, minimize waste, and reduce energy consumption, thereby allowing the facility to be a better steward of its allotted natural resources.

3.3.2.2 Reliability: Assessment of data from the monitoring system can reveal existing or imminent

issues that can adversely affect the operation and product within a facility. Historical data from power monitoring systems can help locate and correct both acute and chronic problems, resulting in increased productivity.

3.3.2.3 Maintenance: Data trends can forecast and notify the appropriate people when discrete

equipment parameters may be exceeded, allowing you to plan ahead instead of facing an unscheduled shutdown.

3.3.2.4 Safety:Monitoring systems can limit the exposure of personnel to potentially hazardous

electrical environments by providing remote status and operational parameters of equipment within hazardous areas. Some monitoring devices also offer a variety of additional parameters (temperature, pressure, flow rate, vibration, status indicators, etc.) through the use of transducers.

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3.3.2.5 Financial: Each benefit discussed above either directly or indirectly influences a business's bottom line. In most cases, the monetary impact from even one or two benefits can quickly justify the purchase and installation of a power monitoring system. Additional advantages offered by power monitoring systems may include features such as accurate evaluations of spare electrical system capacity, billing allocation and validation, or optimum placement of mitigation devices. Once you decide if a power monitoring system makes sense in your particular situation, the next step is narrowing the field of choices.

Generally, Power monitoring systems are based upon human labor that is a line man plays a significant role in collecting and managing field data. However, due to the size increase of consumption areas, this kind of manual practice is considered time consuming and labor intensive.

3.3.3 Real time remote power monitoring system: A real time remote power monitoring systems are used to quickly identify and

resolve problems occurring on their electrical system. Power monitoring systems are permanently installed, they operate on a 24 hours, and continuous logging of energy-related data provides information on the operational characteristics of an electrical system. This includes when, where and how the energy is being consumed, and what loads are consuming the energy. This data can help you reduce the energy delivered to and consumed by your electrical system. The quality of energy supplied to a facility can adversely affect its operation, though leading to loss or degradation of equipment, product, revenue, and reputation, plant managers must weight the advantages of implementing a power monitoring program. Power monitoring systems may include features such as accurate evaluations of spare electrical system capacity, billing allocation and validation.

3.3.3.1 SCADA: The term SCADA stands for Supervisory Control and Data Acquisition. A

SCADA system is a common process automation system which is used to gather data from sensors and instruments located at remote sites and to transmit and display this data at a central site for either control or monitoring purposes. The collected data is usually viewed on one or more SCADA Host computers located at the central or master site. A real world SCADA system can monitor and control hundreds to hundreds of thousands of I/O points [8].

Common analog signals that SCADA systems monitor and control are levels, temperatures, pressures, flow rate and motor speed. Typical digital signals to monitor and control are level switches, pressure switches, generator status, relays & motors.

There is typically another layer of equipment between the remote sensors and instruments and the central computer. This intermediate equipment exists on the remote side and connects to the sensors and field instruments. Sensors typically have digital or analog I/O and these signals are not in a form that can be easily communicated over long

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distances. The intermediate equipment is used to digitize then packetize the sensor signals so that they can be digitally transmitted via an industrial communications protocol over long distances to the central site.

3.3.3.1.1 SCADA Features:The main features of SCADA are :

1. Dynamic process Graphic2. Alarm summery3. Alarm history4. Real time trend5. Historical time trend6. Security (Application Security)7. Data base connectivity8. Device connectivity9. Scripts10. Recipe management

3.3.3.1.2 SCADA Subsystems:A SCADA system usually consists of the following subsystems[8]:1) Human Machine Interface2) A Master Unit3) Remote terminal units (RTUs)4) Programmable logic controller (PLCs)

3.3.3.1.2.1 Human Machine Interface:A human–machine interface (HMI) is the device which presents process data to a

human operator, and through this, the human operator monitors and controls the process. It is linked to the SCADA system's data bases and software programs, to provide trending, diagnostic data, and management information such as scheduled maintenance procedures, logistic information, detailed schematics for a particular sensor, machine and expert-system troubleshooting guides.

The HMI system usually presents the information to the operating personnel graphically, in the form of a mimic diagram. This means that the operator can see a schematic representation of the plant being controlled. The HMI package for the SCADA system includes a drawing program that the operators or system maintenance personnel use to change the way these points are represented in the interface.  A HMI has a nested tree structure of many such screens, usually with the many overview screens on the first page with the most relevant data displayed. Users can easily configure the type of I/O point, communication protocol driver, polling rate, alarm thresholds and notifications, trend process data as well as configure the User and Operator screens. 3.3.3.1.2.2 A Master Unit:

A supervisory system is a host computer or machine that acquires data on the process and sends commands to the process. SCADA master should display information in the most useful way to human operators and intelligently regulate your managed

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systems. It contains a software responsible for communicating with the field equipment (RTUs, PLCs, etc.), and then to the HMI software running on workstations in the control room. The SCADA master station may includes[9]

Flexible and programmable response to sensor inputs:Look for a system that provides easy tools for programming soft alarms (reports

of complex events that track combinations of sensor inputs and date/time statements) and soft controls (programmed control responses to sensor inputs).

24/7, automatic pager and email notification:Why pay personnel to watch a board 24 hours a day? If equipment needs human

attention, the SCADA master can automatically page or email directly to repair technicians.

Detailed information display: You want a system that displays reports in plain English, with a complete

description of what activity is happening and how you can manage it.

Nuisance alarm filtering:Nuisance alarms desensitize your staff to alarm reports, and they can start to

believe that all alarms are nonessential alarms. Eventually they may stop responding even to critical alarms. Look for a SCADA master that includes tools to filter out nuisance alarms.

Expansion capability: An SCADA system is a long-term investment that will last for as long as 10 to 15

years. So you need to make sure it will support your future growth for up to 15 years.

Redundant, geo-diverse backup:The best SCADA systems support multiple backup masters in separate locations.

If the primary SCADA master fails, a second master on the network automatically takes over, with no interruption of monitoring and control functions.

Support for multiple protocols and equipment types: Early SCADA systems were built on closed, proprietary protocols. Single-vendor

solutions aren't a great idea as vendors sometimes drop support for their products or even just go out of business. Support for multiple open protocols safeguards your SCADA system against unplanned obsolescence.

3.3.3.1.2.3 Remote terminal units (RTUs):

Remote terminal units (RTUs) connecting to sensors in the process, converting sensor signals to digital data and sending digital data to the supervisory system. It connects to physical equipment. The RTU converts the electrical signals from the equipment to digital values such as the open/closed status from a switch or a valve, or measurements such as pressure, flow, voltage or current. By converting and sending these

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electrical signals out to equipment the RTU can control equipment, such as opening or closing a switch or a valve, or setting the speed of a pump. The single board RTU normally has fixed I/O e.g. 16 digital inputs, 8 digital outputs, 8 analogue inputs, and say 4 analogue outputs. It is normally not possible to expand its capability. The modular RTU is designed to be expanded by adding additional modules. Typical modules may be a 8 analog in module, a 8 digital out module. Some specialized modules such as a GPS time stamp module may be available.

Fig 3.1 contains SCADA RTU. It is a small ruggedized computer. It has hardware features i-e CPU, volatile memory, Nonvolatile memory for storing programs and data. Communications capability either through serial port(s) or sometimes with an on board modem. Secure Power supply (with battery backup). Watchdog timer (to ensure the RTU restarts if something fails). Electrical protection against "spikes". I/O interfaces to DI/DO/AI/AO's and Real time clock.

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Fig 3.1 A SCADA RTU system [10]

RTU requires the software functionality. In many RTU's these may be intermingled and not necessarily identifiable as separate modules i-e Real time operating system. This may be a specific RTOS, or it may be code that started out life as one big loop scanning the inputs, and monitoring the communications ports. Driver for the communications system i-e the link to the SCADA Master. Device drivers for the I/O system i-e to the field devices. SCADA application e.g. scanning of inputs, processing and storing of data, responding to requests from the SCADA master over the communications network. Some method to allow the user applications to be configured in the RTU. This may be simple parameter setting, enabling or disabling specific I/O's or it may represent a complete user programming environment. Some RTU's may have a file system with support for file downloads. This supports user programs, and configuration files.

3.3.3.1.2.4 Programmable logic controller (PLCs):Programmable logic controller (PLCs) used as field devices because they are

more economical, versatile, flexible, and configurable than special-purpose RTUs. PLCs are capable of autonomously executing simple logic processes without involving the master computer. A standardized control programming language is frequently used to create programs which run on PLCs. Unlike a procedural language such as the C programming language or FORTRAN has minimal training requirements by virtue of resembling historic physical control arrays. This allows SCADA system engineers to perform both the design and implementation of a program to be executed on PLC. A programmable automation controller (PAC) is a compact controller that combines the features and capabilities of a PC-based control system with that of a typical PLC. PACs are deployed in SCADA systems to provide RTU and PLC functions. In many electrical substation SCADA applications.

SCADA is used as a safety tool as in lock-out tag-out used to ensure that dangerous machines are properly shut off and not started up again prior to the completion of maintenance or servicing work. Communication infrastructure connecting the supervisory system to the remote terminal units. Various process and analytical instrumentation

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3.3.3.1.3 SCADA system Operation:

The term SCADA usually refers to centralized systems which monitor and control entire sites, or complexes of systems spread out over large areas. Most control actions are performed automatically by RTUs or by PLCs. These devices employ de- facto standard industrial data communication protocols to transmit the sensor data. The SCADA Host is usually industrial PC running sophisticated SCADA HMI (Human Machine Interface) software. This software is used to poll the remote sites and store the collected data as shown in Figure 3.2. Logic can be configured in the SCADA host software which then monitors and controls plant or equipment. The control may be automatic, or initiated by operator commands.

Fig 3.2 SCADA system Operation

Once the data has been acquired at sent to the SCADA Host, the HMI software will scan the acquired data. There are 3 common types of data collected i-e Analog which is used for trending, Digital (on/off) which is used for alarming and Pulse (i.e. revolutions of some kind of meter), accumulated /counted. The data is then processed to detect preset alarm conditions, and if an alarm is present, an alarm message will flash on the operator screen and added to an alarm list. The operator must then acknowledge this alarm.

SCADA system may allow operators to change the set points for the flow, and enable alarm conditions, such as loss of flow and high temperature, to be displayed and recorded. The feedback control loop passes through the RTU or PLC, while the SCADA system monitors the overall performance of the loop. SCADA systems implement a distributed database, commonly referred to as a tag database, which contains data elements called tags or points. A point represents a single input or output value monitored or controlled by the system. 

3.4 A Proposed model:We have proposed a model that can limit the power that is allocated to any

household consumer and it can’t operate on load exceeding the allocated limit. Through this model, no any consumer exceeds the power limit and thus the load can be forecasted in the particular area. Also power is saved and limited and if all the consumers maintain

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the power limit, we can forecast the load and generate the power accordingly. Now if any consumer wants to use load greater than the limit then he can ask the Power Company to increase its power limit or he should generate his own power for his further requirement. From this there comes a smart grid solution for own power generation.

Our proposed model hardware and software implementation is discussed in further chapters.

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CHAPTER 4

HARDWARE AND IMPLEMENTATION

The block diagram, hardware components and system flow chart are defined in the following sections.

4.1 BLOCK DIAGRAM:

Fig 4.1 Block diagram of project

The block diagram contains Voltage and Current Transformers (VT and CT) of main line and devices along with Microcontroller i-e Atmega328. The current and voltage transformers are used to measure the main line currents and voltages respectively.

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The measured data is fed to the Analog to Digital Converter(ADC) of microcontroller. Microcontroller is further connected to the ULN2003 IC. ULN2003 IC is a current driver ,used to drive the relay devices. Each device has its separate current and voltage transformer for measuring the current and voltage for the device.

The system operation is done by the microcontroller through a dynamic programming. Programming is done in such a way that if a load exceeds by a particular mentioned load then relay of particular device may turn off the device immediately otherwise load will remain turned on. Liquid crystal display (LCD) is also connected to the microcontroller and that shows the current, voltage and power measured by transformers.

The flow chart of the system defining operations in given below:

4.2 Flow chart:

Fig 4.2: Flow chart of system

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4.3 Hardware Components:

The hardware components that we used for our project include:

1. Arduino UNO(Atmega328 Microcontroller)2. ULN2003 IC3. Liquid Crystal Display4. Current Transformer5. Voltage Transformer6. Diode Bridge7. LM7805(Voltage Regulator IC)8. Potentiometers9. Indicators

4.3.1. Arduino UNO development board

Fig 4.3 Arduino UNO Development Board[11]

4.3.1.1 OverviewThe Arduino Uno is a microcontroller board based on the ATmega328(shown in figure 3.1). It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic resonator, a USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started.

4.3.1.2 Features:Microcontroller ATmega328Operating Voltage 5V

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Input Voltage (recommended) 7-12VInput Voltage (limits) 6-20VDigital I/O Pins 14 (of which 6 provide PWM output)Analog Input Pins 6DC Current per I/O Pin 40 mADC Current for 3.3V Pin 50 mAFlash Memory 32 KB (ATmega328) of which 0.5 KB used by bootloaderSRAM 2 KB (ATmega328)EEPROM 1 KB (ATmega328)Clock Speed 16 MHz

4.3.1.3 PowerThe Arduino Uno can be powered via the USB connection or with an external power supply. The power source is selected automatically.

External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. The adapter can be connected by plugging a 2.1mm center-positive plug into the board's power jack. Leads from a battery can be inserted in the Gnd and Vin pin headers of the POWER connector.

The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts.

The power pins are as follows:

4.3.1.3.1 VIN: The input voltage to the Arduino board when it's using an external power source (as opposed to 5 volts from the USB connection or other regulated power source). You can supply voltage through this pin, or, if supplying voltage via the power jack, access it through this pin.

4.3.1.3.2 “5V”:This pin outputs a regulated 5V from the regulator on the board. The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it.

4.3.1.3.3 “3V3”: A 3.3 volt supply generated by the on-board regulator. Maximum current draw is 50 mA.

4.3.1.3.4 GND: Ground pins.

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4.3.1.3.5 IOREF: This pin on the Arduino board provides the voltage reference with which the microcontroller operates. A properly configured shield can read the IOREF pin voltage and select the appropriate power source or enable voltage translators on the outputs for working with the 5V or 3.3V.

4.3.1.4 MemoryThe ATmega328 has 32 KB (with 0.5 KB used for the bootloader). It also has 2 KB of SRAM and 1 KB of EEPROM (which can be read and written with the EEPROM library).

4.3.1.5 Input and OutputEach of the 14 digital pins on the Uno can be used as an input or output, using pinMode(), digitalWrite(), and digitalRead() functions. They operate at 5 volts. Each pin can provide or receive a maximum of 40 mA and has an internal pull-up resistor (disconnected by default) of 20-50 kOhms. In addition, some pins have specialized functions:

1. Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data. These pins are connected to the corresponding pins of the ATmega8U2 USB-to-TTL Serial chip.

2. External Interrupts: 2 and 3. These pins can be configured to trigger an interrupt on a low value, a rising or falling edge, or a change in value. See the attachInterrupt() function for details.

3. PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the analogWrite() function.

4. SPI: 10 (SS), 11 (MOSI), 12 (MISO), 13 (SCK). These pins support SPI communication using the SPI library.

5. LED: 13. There is a built-in LED connected to digital pin 13. When the pin is HIGH value, the LED is on, when the pin is LOW, it's off.

6. The Uno has 6 analog inputs, labeled A0 through A5, each of which provide 10 bits of resolution (i.e. 1024 different values). By default they measure from ground to 5 volts, though is it possible to change the upper end of their range using the AREF pin and the analogReference() function. Additionally, some pins have specialized functionality:

7. TWI: A4 or SDA pin and A5 or SCL pin. Support TWI communication using the Wire library.

8. There are a couple of other pins on the board:9. AREF. Reference voltage for the analog inputs. Used with analogReference().10. Reset. Bring this line LOW to reset the microcontroller. Typically used to add a

reset button to shields which block the one on the board.

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4.3.1.6 CommunicationThe Arduino Uno has a number of facilities for communicating with a computer, another Arduino, or other microcontrollers. The ATmega328 provides UART TTL (5V) serial communication, which is available on digital pins 0 (RX) and 1 (TX). An ATmega16U2 on the board channels this serial communication over USB and appears as a virtual com port to software on the computer. The '16U2 firmware uses the standard USB COM drivers, and no external driver is needed. However, on Windows, a .inf file is required. The Arduino software includes a serial monitor which allows simple textual data to be sent to and from the Arduino board. The RX and TX LEDs on the board will flash when data is being transmitted via the USB-to-serial chip and USB connection to the computer (but not for serial communication on pins 0 and 1).

A SoftwareSerial library allows for serial communication on any of the Uno's digital pins.

4.3.1.7 ProgrammingThe Arduino Uno can be programmed with the Arduino software (download).

Select "Arduino Uno from the Tools > Board menu (according to the microcontroller on your board).

The ATmega328 on the Arduino Uno comes preburned with a bootloader that allows you to upload new code to it without the use of an external hardware programmer. It communicates using the original STK500 protocol (reference, C header files).

You can also bypass the bootloader and program the microcontroller through the ICSP (In-Circuit Serial Programming) header; see these instructions for details.

The ATmega16U2 (or 8U2 in the rev1 and rev2 boards) firmware source code is available . The ATmega16U2/8U2 is loaded with a DFU bootloader, which can be activated by:

On Rev1 boards: connecting the solder jumper on the back of the board (near the map of Italy) and then resetting the 8U2.

On Rev2 or later boards: there is a resistor that pulling the 8U2/16U2 HWB line to ground, making it easier to put into DFU mode.

4.3.1.8 Automatic (Software) Reset

Rather than requiring a physical press of the reset button before an upload, the Arduino Uno is designed in a way that allows it to be reset by software running on a connected computer. One of the hardware flow control lines (DTR) of

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theATmega8U2/16U2 is connected to the reset line of the ATmega328 via a 100 nanofarad capacitor. When this line is asserted (taken low), the reset line drops long enough to reset the chip. The Arduino software uses this capability to allow you to upload code by simply pressing the upload button in the Arduino environment. This means that the bootloader can have a shorter timeout, as the lowering of DTR can be well-coordinated with the start of the upload.

This setup has other implications. When the Uno is connected to either a computer running Mac OS X or Linux, it resets each time a connection is made to it from software (via USB). For the following half-second or so, the bootloader is running on the Uno. While it is programmed to ignore malformed data (i.e. anything besides an upload of new code), it will intercept the first few bytes of data sent to the board after a connection is opened. If a sketch running on the board receives one-time configuration or other data when it first starts, make sure that the software with which it communicates waits a second after opening the connection and before sending this data.

The Uno contains a trace that can be cut to disable the auto-reset. The pads on either side of the trace can be soldered together to re-enable it. It's labeled "RESET-EN". You may also be able to disable the auto-reset by connecting a 110 ohm resistor from 5V to the reset line.

4.3.1.9 USB Overcurrent Protection

The Arduino Uno has a resettable polyfuse that protects your computer's USB ports from shorts and overcurrent. Although most computers provide their own internal protection, the fuse provides an extra layer of protection. If more than 500 mA is applied to the USB port, the fuse will automatically break the connection until the short or overload is removed.

4.3.1.10 Physical Characteristics and Shield Compatibility

The maximum length and width of the Uno PCB are 2.7 and 2.1 inches respectively, with the USB connector and power jack extending beyond the former dimension. Four screw holes allow the board to be attached to a surface or case. Note that the distance between digital pins 7 and 8 is 160 mil (0.16"), not an even multiple of the 100 mil spacing of the other pins.

4.3.1.11 Pin Mappings of the Board with Microcontroller

The pin mapping for the board with microcontroller is shown in the following table.

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Table 4.1: Arduino and Atmega328 Pin Mapping

Arduino UNO

functionATMEGA 328 PIN

Arduino UNO

functionATMEGA 328 PIN

Reset PC6(PCINT14/Reset) Analog Input 5

PC5(ADC5/PCINT13)

Digital PIN 0(RX)

PD0(PCINT16/RXD) Analog Input 4

PC4(ADC4/PCINT12)

Digital PIN 1(TX)

PD1(PCINT17/TXD) Analog Input 3

PC3(ADC3/PCINT11)

Digital PIN 2

PD2(PCINT18/INT0) Analog Input 2

PC2(ADC2/PCINT10)

Digital PIN

3(PWM)

PD3(PCINT19/OC2B/INT1) Analog Input 1

PC1(ADC1/PCINT9)

Digital PIN 4

PD4(PCINT20/XCK/T0) Analog Input 0

PC0(ADC0/PCINT8)

VCC VCC GND GNDGND GND Analog

ReferenceAREF

Crystal PB6(PCINT6/XTAL1/TOSC1) VCC AVCCCrystal PB7(PCINT7/XTAL2/TOSC2) Digital PIN

13PB5(SCK/PCINT5)

Digital PIN

5(PWM)

PD5(PCINT21/OC0B/T1) Digital PIN 12

PB4(MISO/PCINT4)

Digital PIN 6

PD6(PCINT22/OC0A/AIN0) Digital PIN 11

(PWM)

PB3(MOSI/OC2A/PCINT3)

Digital PIN 7

PD7(PCINT23/AIN1) Digital PIN 10

PWM

PB2(SS/OC1B/PCINT2)

Digital PIN 8

PB0(PCINT0/CLCO/ICP1) Digital PIN 9

PWM

PB1(OC1A/INT1)

4.3.2 ULN2003:The ULN2003 is a monolithic high voltage and high current Darlington transistor

arrays. It consists of seven NPN darlington pairs that features high-voltage outputs with common-cathode clamp diode for switching inductive loads.

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Fig 4.4 ULN2003 IC Internal Connection[13]

The collector-current rating of a single darlington pair is 500mA. The darlington pairs may be paralleled for higher current capability. Applications include relay drivers, hammer drivers, lamp drivers, display drivers(LED gas discharge),line drivers, and logic buffers. The ULN2003 has a 2.7kW series base resistor for each Darlington pair for operation directly with TTL or 5V CMOS devices. Its internal connection is shown in figure 3.2

4.3.3 Liquid Crystal Display

LCD (Liquid Crystal Display) screen is an electronic display module and find a wide range of applications. A 16x2 LCD display is very basic module and is very commonly used in various devices and circuits. These modules are preferred over seven segments and other multi segment LEDs. The reasons being: LCDs are economical; easily programmable; have no limitation of displaying special & even custom characters (unlike in seven segments), animations and so on.A 16x2 LCD means it can display 16 characters per line and there are 2 such lines(shown in figure 3.3). In this LCD each character is displayed in 5x7 pixel matrix. This LCD has two registers, namely, Command and Data.The command register stores the command instructions given to the LCD. A command is an instruction given to LCD to do a predefined task like initializing it, clearing its screen, setting the cursor position, controlling display etc. The data register stores the data to be displayed on the LCD. The data is the ASCII value of the character to be displayed on the LCD.

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Fig 4.5 Pin Configuration 16*2 LCD

4.3.3.1 Pin Description: The pin description for the LCD is given in the table below:

Table 4.2 LCD Pin Description

 Pin No  Function  Name

1 Ground (0V) Ground2 Supply voltage; 5V (4.7V – 5.3V)  Vcc3 Contrast adjustment; through a variable resistor  VEE

4 Selects command register when low; and data register when high

Register Select

5 Low to write to the register; High to read from the register Read/write6 Sends data to data pins when a high to low pulse is given Enable7

8-bit data pins

DB08 DB19 DB210 DB311 DB412 DB513 DB614 DB715 Backlight VCC (5V) Led+16 Backlight Ground (0V) Led-

RS, register selectThere are two very important registers inside the LCD. The RS pin is used for their selection asfollows.

If RS = 0, the instruction command code register is selected, allowing the user to send a command such as clear display, cursor at home, etc.

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If RS = 1, the data register is selected, allowed the user to send data to be displayed on the LCD.

R/W, read/writeR/W input allows the user to write information to the LCD or read information from it. R/W = 0 when writing, R/W = 1 when reading. For most applications, there really is no reason to read from the LCD. R/W is usually tied to ground.

EN, enableThe enable pin is used by the LCD to latch information presented to its data pins. When data issupplied to data pins, a high-to-low pulse must be applied to this pin in order for the LCD tolatch in the data present at the data pins (data is written to the LCD at the falling edge of the ENline).

Data, DB7 – DB0 The 8-bit data pins, DB7-DB0, are used to send information (data-ASCII code, or

LCD command) to the LCD. To display letters or numbers, we send ASCII codes for the letter s A-Z, a – z, and

numbers 0-9 to these pins while making RS = 1. To send instruction command codes, the following command codes can be sent to

LCD while making RS = 0.

4.3.4 Voltage Transformer

Voltage transformers are widely used in power distribution systems. They step up or step down the voltage according to the need of the system. There are two windings namely primary and secondary. It works on the Faradays Law of Electromagnetic Induction that states that “any change in the magnetic environment of a coil of wire will cause a voltage (emf) to be induced in the coil. No matter how the change is produced, the voltage will be generated. The change could be produced by changing the magnetic field strength, moving a magnet towards or away from the coil, moving the coil into or out of the magnetic field, rotating the coil relative to the magnet, etc”.

Both wires in a transformer are actually wrapped in a coil around an iron core(as shown in figure 4.6). The iron core is immersed in an insulating oil bath which does not conduct electricity well. The coils of wire are not physically connected. One wire has more turns in its coil than the other wire. The different numbers of coils in the two wires causes the voltage and current in each wire to be different from the other wire. By designing the transformer with just the right number of coils in each wire, electrical engineers can control exactly how much the transformer changes the voltage from the incoming to the outgoing wire.

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Fig 4.6 Transformer

Transformers only work with AC (alternating current) circuits. Since the AC current on the "incoming" wire is constantly changing, the magnetic field it creates changes too. The changing magnetic field is what forces current to flow in the "outgoing" wire.

Transformers are passive devices - they don't add power. A high voltage and low current exits the transformer carrying almost the same amount of power along the transmission lines that the incoming low voltage and high current did. Transformers are very efficient. Under normal conditions they transmit about 99% of the power that enters them (about 1% of the power is lost as heat).

4.3.5 Current Transformer:A current transformer (CT) is used for measurement of electric currents. Current

transformers, together with voltage transformers (VT) (potential transformers (PT)), are known as instrument transformers. When current in a circuit is too high to directly apply to measuring instruments, a current transformer produces a reduced current accurately proportional to the current in the circuit, which can be conveniently connected to measuring and recording instruments. A current transformer also isolates the measuring instruments from what may be very high voltage in the monitored circuit. Current transformers are commonly used in metering and protective relays in the electrical power industry.

The current transformer used to measure current in main line, and also to measure the current that the load takes. For that we have used 3 current transformers in our project. Current transformer is shown in fig 4.7

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Fig 4.7: Current Transformer

4.3.6 Diode BridgeA diode bridge is an arrangement of four (or more) diodes in a bridge

circuit configuration that provides the same polarity of output for either polarity of input. When used in its most common application, for conversion of an alternating current (AC) input into a direct current (DC) output, it is known as a bridge rectifier. A bridge rectifier provides full-wave rectification from a two-wire AC input, resulting in lower cost and weight. The essential feature of a diode bridge is that the polarity of the output is the same regardless of the polarity at the input. Diode bridge is shown in fig 4.8 below

Fig 4.8 Diode Bridge Full Wave rectifier

4.3.7 Regulator IC LM7805

This is a 5 volts regulator IC of the series LM78XX. The LM78XX series of three terminal regulators is available with several fixed output voltages making them useful in a wide range of applications. One of these is local on card regulation, eliminating the distribution problems associated with single point regulation. The voltages available allow these regulators to be used in logic systems, instrumentation, HiFi, and other solid state electronic equipment. Although designed primarily as fixed voltage regulators these devices can be used with external components to obtain adjustable voltages and currents.

It is a 3 terminal IC as shown in fig 4.9,having output current up to 1.5 A.

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Fig 4.9 LM7805 IC

4.4 Implementation:

Before making a model of this system, firstly the microcontroller was programmed and tested on the breadboard to see the main working of the controller. And the errors and problems were solved. The system test hardware on breadboard is shown in the following figure 4.10.

Fig4.10: Project Test Hardware in Breadboard

For all the hardware components, a panel is made where all the components are assembled and connected together, as shown in fig 4.11.

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Fig 4.11 Real Implemented System

There are two power sockets given for the load where any device can be connected to make it operate. There are total of 7 transformers connected, of which one voltage transformer is for power supply, 3 voltage transformers for voltage measurement and 3 current transformers for current measurement. After each transformer there is Diode Bridge that converts AC voltage to DC. The current is also measured in terms of voltage. The measured voltage and current are in the range of 0-5 Volts DC. These measured voltages and currents are given to the analog inputs (ADC inputs) of the microcontroller. The microcontroller takes the product of voltage and current to calculate the power in the line. If the main line is running on full load (threshold), then the RED indicator glows showing that the main line is already on full load and no device can be turned on, if the main line is under load, green indicator glows showing that further devices can be turned on. When any device is connected on the power socket, and switched on, initially its relay is on, now the current and voltage is measured through microcontroller and added to the

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main line, if the main line exceed the threshold, the relay for that device is energized and the contact is open and the device doesn’t operate irrespective of its power switch. If the main line does not exceed the threshold the relay is left uncharged and the device operates. This way the main line in any way doesn’t exceed the power limit (here we have power limit of 2 KW).

For relay operation through microcontroller, we have used ULN2003 to regulate/maintain the current to each relay for energizing. The PCB circuit for ULN2003 and relay operating is shown in following fig 4.12.

Fig 4.12 PCB Relay Interfacing Circuit

4.4.1 ADC Reading:

The transformers measure the current and transformer scaled upto 0-5 Volts DC, when this signal is applied to ADC of the microcontroller, the ADC output value is in the

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binary value, so in order to calculate the original analog signal, we apply the following formula:

Analog value = (Vref*ADC value) /resolution(max adc value)

And here we have 5 volts reference value and resolution is 10 bit, so max adc value is 1024. So the formula we used to calculate analog input value from transformers is

Analog input Voltage =48*( (5*ADC value)/1024)

Analog input Current = 2*( (5*ADC value)/1024)

4.5 Result:

When the main line is running on 1 Kw load Green indicator glows which shows the main line is under load and further load can be derived. Now suppose we turn on a device of 100 watt, it is turned on because the main line doesn’t exceed the load limit. But if we try to turn on a load of 1 Kw when main line is already on 1.1 Kw, microcontroller measures its power and since turning this load on will make the main line 2.1 kw which is more than the allocated load(i-e 2 Kw), hence the microcontroller energizes the relay for that device and the load is disconnected from the phase. This way the devices that make derive the load making main line greater than load limit, are not switched on and this way the main line in anhy way doesnot exceeds the allocated load.

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CHAPTER 5

SOFTWARE AND SIMULATION

The softwares used for the project are:

1. Protues 7(Simulator)2. Multisim3. ARES(PCB Design)4. Arduino Development Software(Programming)

5.1 Protues 7(Circuit Simulator)

Protues is a circuit simulator that is used to draw circuit schematics and also to simulate the circuit before implementing so that the developer observes circuit operation and to correct errors if any. For our project, we programmed the microcontroller and then simulated the test circuit by placing the potentiometers in place of current and voltage measurement transformers to see how the circuit works. The circuit schematics of microcontroller with LCD and potentiometers is shown below in fig 5.1

Fig 5.1 Schematics of the Microcontroller Circuit

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Now for relay operating through microcontroller, we have made separate circuit that is connected with the outputs of the microcontroller, it uses ULN2003 IC. Schematic for the interfacing circuit is shown below in figure 5.2.

Fig 5.2 Schematic of the Relay Interfacing Circuit

As microcontroller is embedded on the Arduino UNO kit, so we didn’t need to go for PCB of this circuit but we made the PCB for the relay interfacing with the microcontroller through ULN2003, shown in figure 5.2

4.1 Current and Voltage Measuring Circuit:For measuring current and voltage, CT and VT are used that scale down the actual values and then rectified so as to measure those values on ADC. The schematic is given below in figure 4.4.

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Fig 5.3 PCB Layout of Relay Interfacing Circuit

Fig 5.4: Current and Voltage Measuring Circuit

4.2 Programming:

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The programming is done in C language through Arduino Alpha development software. Programming code is given below:

#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

//device 1 input

int input_voltage1 = A0;

int input_current1 = A1;

//device 2 input

int input_voltage2 = A2;

int input_current2 = A3;

//main line input

int main_voltage = A4;

int main_current = A5;

int relay1 = 8; //outptu relay for device 1

int relay2 = 9; //output relay for device 2

int led = 10; //output status for main line

float v1 = 0; // variable to store the ADC value coming from the analog inputs

float i1 = 0;

float v2 = 0;

float i2 = 0;

float v = 0;

float i = 0;

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float voltage1; //variable to store the analog input values

float current1;

float voltage2;

float current2;

float voltage;

float current;

float power1; //variables for power

float power2;

float main_power;

void setup() {

// declare the relay pins as outputs:

pinMode(relay1, OUTPUT);

pinMode(relay2, OUTPUT);

pinMode(led, OUTPUT);

// set up the LCD's number of columns and rows:

lcd.begin(16, 2);

}

void loop() {

lcd.setCursor(0,1);

lcd.print("M.Power: ");

// read the value from the inputs

v1 = analogRead(input_voltage1); //digital value from ADC input (1010100010)

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i1 = analogRead(input_current1);

v2 = analogRead(input_voltage2);

i2 = analogRead(input_current2);

v = analogRead(main_voltage);

i = analogRead(main_current);

voltage1 = 48*((5*v1)/1024); //calculate analog value from digital value...reference voltage 5 volts, resolution 10 bits

current1 = 2*((5*i1)/1024);

power1 = voltage1*current1;

voltage2 = 48*((5*v2)/1024); //calculate analog value from digital value...reference voltage 5 volts, resolution 10 bits

current2 = 2*((5*i2)/1024);

power2 = voltage2*current2;

voltage = 48*((5*v)/1024); //calculate analog value from digital value...reference voltage 5 volts, resolution 10 bits

current = 2*((5*i)/1024);

main_power = voltage*current;

if((main_power + power1)>=2000)

digitalWrite(relay1,LOW);

else digitalWrite(relay1,HIGH);

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if((main_power + power2)>=2000)

digitalWrite(relay2,LOW);

else digitalWrite(relay2,HIGH);

if(main_power>=2000)

digitalWrite(led, HIGH);

else digitalWrite(led, LOW);

lcd.setCursor(0,0); //set LCD cursor 1st row 1st column

// Print a values to the LCD.

lcd.print(power1);

lcd.print(" W");

lcd.setCursor(9,0);

lcd.print(power2);

lcd.print(" W");

lcd.setCursor(9,1);

delay(500);

lcd.print(main_power);

lcd.print(" W");

}//end

CHAPTER 6

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CONCLUSION AND FUTURE WORK

6.1 Conclusion

Through this project, we tried to improve the electrical power monitoring and load forecasting by applying the method of load limiting at consumer side. If this system is employed in Pakistan, the Electrical Power Company can have better view about the load usage of each household per day and consequently load forecasting can be done, which will result in the power generation meeting the consumer demand. Hence many problems that occur in today’s society, like power shortage, load shedding, transformer overloading, can be solved.

6.2 Future Advancements

There can be many features added to the system, like we can make a database of all the households on daily basis, smart grid additions can be done. We can add the feature that when any household consumer wants to consume load more than allocated then he can generate his own power. Real time monitoring can be added, smart metering can be employed with this system which will monitor all the parameters on the main line. Programming in C language can be done in java by which monitoring system software can be designed. This system will prove much efficient in future and we will have much less power deficient Pakistan.

REFERENCES42

[1] Canadian Electricity Association, A discussion paper ‘The smart grid, a programmatic approach”, released on March 25, 2010.pp 5-6

[2] Ken Barne, Briam Johnson ”Introduction To SCADA Protection And Vulnerabilities” , idaho National Engineering and Environmental LaboratoryBechtel BWXT Idaho, LLC, released on March 2004, chapter 01 pp 1-6

[3]A Report on “An Overview of Electricity Sector In Pakistan”, Chamber of commerce & industry , Islamabad, released in 2011,pp 3-5

[4] V. Hamidi, F. Li, F. Robinson, Demand response in the UK’s domestic sector, Electric Power Systems Research 79 ,released in 2009 ,1722-1726, pp1-3

[5]NTDC, Electricity demand forecast Based on Regression Analysis(Period 2008 to 2030), pp 19-22

[6] Fikri Prof Dr. Zahir Ahmed , “Introduction of new technologies for renewables and demand side management in the power sector in Pakistan”,paper no.261,released in 2008 , pp 37-39

[7] Dr,M. Arshad Javaid1, Sarfraz Hussain, Abdul-Maqsood, Dr. Zeba Arshad,Dr. M.Awais Arshad , Majid Idrees, “Electrical Energy Crisis in Pakistan and Their Possible Solutions”, International Journal of Basic & Applied Sciences IJBAS-IJENS Vol: 11 No: 05, 110505-9393 IJBAS-IJENS , published in October 2011 IJENS, pp 39

[8] Marek Zima and Marija Boˇckarjova, “Operation, Monitoring andControl Technology of Power Systems”, Lecture 227-0528-00, ITET ETH, March 2007, pp 26-29

[9] DPS Telecom , “A Quick, Easy, Comprehensive Guide on SCADA Tutorial’, Version 2.0 ,Released August 8, 2011

[10] http://members.iinet.net.au/~ianw/rtu.html , Last excess date :Feb 04, 2013

[11] http://arduino.cc/en/Main/ArduinoBoardUno Last excess date : Feb 04, 2013

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