DESIGN AND CONSTRUCTION OF A GSM-BASED ENERGY METER
Wireless automation in the generation, transmission and distribution of electricity and billing has come of age. Traditional metering methods for retrieving the energy data of consumers is not convenient. The present system of energy billing is error prone, time, resource and labour consuming. The problem worsens when consumers try to bypass meter units, thereby pay less than what is actually consumed or the case of overbilling by the Electricity Company as the case in many Nigerian houses.
This paper presents the design and implementation of a GSM based remote operation of an energy meter which proffers the solution to power theft, consumption control, auto billing and payment, data logging and labour reduction in power distribution and management
The objective of this project is to facilitate energy consumption measurement and its corresponding billing scheme.
The materials and method deployed herein is the use of a microcontroller unit that continually monitors the meter interfaced with a GSM MODEM with a dedicated SIM for remote operations. The method used to carry out this project is the principle of serial communication in collaboration with embedded systems. The meter provides corresponding billing Information on a LCD screen.
TABLE OF CONTENTS
COVER PAGE i
TITLE PAGE ii
LIST OF FIGURES viii
i. BACKGROUND 1
ii. PROBLEM STATEMENT 2
iii. OBJECTIVES 2
iv. SIGNIFICANCE 3
v. SCOPE 3
LITERATURE REVIEW 5
2.1 HISTORY OF ELECTRIC ENERGY METERS 5
DIRECT CURRENT (DC)5
ALTERNATING CURRENT (AC)6
UNITS OF MEASUREMENT6
TYPES OF METERS7
SOLID STATE DESIGN9
TAMPERING AND SECURITY IN ENERGY METERS14
POWER LINE RELATED INTELLIGENT METERING (PRIME)15
INTRODUCTION TO GSM NETWORK15
MESSAGING OVER GSM NETWORK16
GSM NETWORK STRUCTURE17
DESIGN AND CONSTRUCTION PROCEDURE 18
SYSTEM BLOCK DIAGRAM19
SECTION A. DESIGN PROCEDURE 19
REGULATED POWER SUPPLLY20
ZENER REGULATOR DESIGN23
TRANSISTOR TIP 4125
LM317T VOLTAGE REGULATOR25
RATED DC OUTPUT27
CURRENT SENSING DESIGN27
THE MICROCONTROLLER UNIT32
CRYSTAL OSCILLATOR DESIGN36
INTERFACING THE LCD WITH THE MICROCONTROLLER39
INTERFACING THE GSM MODEM WITH MICROCONTROLLER41
THE MAX 232 IC43
SECTION B: CONSTRUCTION PROCEDURE 49
CIRCIUT DESIGN USING PRINTED CIRCIUT BOARD (PCB)49
CASING AND PACKAGING51
PERFORMANCE AND COST EVALUATION 55
LIST OF TABLES
TABLE 3.1 PIC18F2550 FEATURES 33
TABLE 3.2 VALUE OF CAPACITOR USED 36
TABLE 3.3 LCD PIN FUNCTIONS 40
TABLE 3.4 AT COMMAND AND RESPONSE 42
TABLE 4.1 SMS COMMAND AND FUNCTIONS 59
TABLE 4.1 COST EVALUATION 60
LIST OF FIGURES
FIG 2.1 A 3Ø electromechanical induction meter, metering 100 A 240/415 V supply 7
FIG 2.2 A digital meter 8
FIG 2.3 A solid state energy meter design 9
FIG 2.4 PRIME core structure 15
FIG 2.5 GSM network structure 17
FIG 3.1 SYSTEM BLOCK DIAGRAM 19
FIG. 3.2 POWER RECTIFICATION CIRCUIT 20
FIG.3.3 ZENER REGULATOR CIRCUIT 24
FIG. 3.4 TIP 41 BUFFER TRANSISTOR 25
FIG. 3.5 BLOCK DIAGRAM OF LM317T 26
FIG. 3.6 LM 317T IN CIRCUIT REGULATION 26
FIG. 3.7 FUNCTIONAL BLOCK DIAGRAM OF ACS755-100CB 28
FIG. 3.8 OUTPUT VOLTAGE VS SENSED CURRENT OF ACS755 AT 5.0 V POWER
SUPPLY AND VARYING TEMPERATURE 29
FIG. 3.9 CURRENT SENSOR CIRCUITRY 30
FIG. 3.10 THE RELAY CIRCUIT 31
FIG. 3.11 THE PIC18F2550 PIN CONFIGURATION 33
FIG.3.12 BLOCK DIAGRAM OF PIC18F2550 35
FIG.3.13 CRYSTAL OSCILLATOR CIRCUIT 37
FIG. 3.14 LED SCHEMATIC SYMBOL AND I-V CHARACTERISTICS CURVES SHOWING THE DIFFERENT COLOURS AVAILABLE 38
FIG. 3.15 SERIES LED CONNECTION 38
FIG.3.16 LCD 40
FIG. 3.17 SMART GSM MODEM 41
FIG.3.18 INSERTING/REMOVING THE SIM CARD INTO THE MODEM 42
FIG.3.19 TYPICAL OPERATING CIRCUIT OF THE MAX 232 IC 44
FIG.3.20 THE MAX 232 INTERFACED WITH DB9 CONNECTOR TO MODEM 44
FIG.3.21 CIRCUIT DIAGRAM OF GSM BASED ENERGY METER 45
FIG. 3.23 FLOWCHART OF PROGRAMME 48
FIG. 3.24 PCB LAYOUT 50
FIG. 3.25 PLY WOOD SURFACE MOUNTING 51
FIG. 3.26 TOP VIEW OF CASING 52
FIG. 3.27 INSIDE VIEW OF PVC CASING 52
LIST OF PLATES
PLATE 3.1 SOLDERED COMPONENTS MOUNTED ON PCB 50
PLATE 3.2 SET UP OF GSM BASED ENERGY METER 53
PLATE 3.3 CASING OF METER UNIT SHOWING THE COMPONENTS AND GSM
PLATE 4.1 THE METER UNIT INDICATING MODEM IS CONNECTED 55
PLATE 4.2 THE METER UNIT WITH LOAD CONNECTED 55
PLATE 4.3 LCD SCREEN INDICATING ENERGY CONSUMPTION DETAILS 56
PLATE 4.4 LCD SCREEN INDICATING THE METER CHECKING FOR SMS 56
PLATE 4.5 SCREEN SHOT OF SMS RECEIVED FROM THE METER UNIT 57
Today, humanity can be classified as living in a “machine society” where technological tools are predominantly at different levels, interfacing in the day–to-day activity of man.
These livelihood activities constitute and deliver economic, social and political benefits and potential risks to the survivability of nations –especially developing nations like ours.
Electricity has become one of the basic requirements of human civilization, being widely deployed for domestic, industrial and agricultural purposes. In spite of the very well developed sources of electricity, there are a number of problems with distribution, metering, billing and control of consumption. Electricity is one of the vital requirements for sustainment of comforts of life and so it should be used very judiciously for its proper utilization . But in our country we have lot of localities where we have surplus supply for the electricity while many areas do not even have access to it. Our policies of its distribution are also partially responsible for this because we are still not able to correctly estimate our exact requirements and still power theft is prevailing .
On the other hand consumers are also not satisfied with the services of power companies, most of the time they have complaints regarding statistical errors in their monthly bills.
Thus this project presents an innovation towards the minimization of technical errors and reduction in human dependency at the same time. With the help of this project the monthly energy consumption of a consumer will be received from a remote location directly. In this way human effort needed to record the meter readings which are till now recorded by visiting
every home individually is reduced. This results in considerable loss of human hours and also provides considerable details regarding the average consumption of a locality so that power supply can be made according to these data. This will help the officials in deciding the specifications of transformers and other instruments required in power transmission and distribution.
This idea is economically efficient as well because the meter reading can be gotten at a very low cost. The implementation is done in such a way that a SMS is delivered to the GSM MODEM whose reading is to be noted and then that meter replies to the server in the SMS format and it is known that SMS costs are very low.
The GSM AMR takes the advantage of available GSM infrastructure nationwide coverage and the Short Messaging System (SMS) cell broadcasting feature to request and retrieve individual houses and building power consumption reading back to the energy provider wirelessly.
In Conventional metering system to measure electricity consumption the energy provider company hire persons to visit each house and record meter reading manually which is used for billing, the bill then sent to consumer by post or hand delivery, this is not only sluggish but laborious, with the company having no control over these meters. There is a stark amount of revenue loss being incurred by our country due to energy theft which is a serious problem, people try to manipulate meter reading by adopting various corrupt practices such as current reversal, partial earth fault condition, bypass meter, magnetic interference etc. . With the aid of this project a definite solution is proffered which allows power companies to have total control over energy meters and have real time information of same from a remote location with little human effort and at reduced cost as compared to conventional methods.
The purpose of this project is the remote monitoring and control of the domestic energy meter; its aims includes: to design a circuit which continuously monitors the meter reading and sends message to electricity company, programming of the GSM MODEM with AT (Attention) command sequence, interfacing the programmable chip with the personal computer, interfacing the programmable chip with the energy meter, interfacing of GSM MODEM with the programmable chip, sending messages from the remote phone to control device.
The significance of these project benefits the Consumers of electric service and the electric services company as it provides precise consumption information, clear and accurate billing, automatic outage information and faster recovery, better and faster customer service, smart automated processes instead of manual work, accurate information from the network load to optimise maintenance and investments, detection of tampering of meters, demand and distribution management, better company credibility, consumer meter reading which eliminates cost and inadequacies of manual reading, observation and control of energy consumption and production, this is useful for planning and power allocation purposes.
The project provides learning’s on the following advancements in terms of theory practice: GSM modem interfacing to Microcontroller, PC interfacing with GSM modem, energy meter interfacing to Microcontroller, embedded C programming, PCB (printed circuit board) design, LCD interfacing to Microcontroller.
The scope of this project is to design and construct GSM based a one phase two wire energy meter with voltage rating of 220V, current of 25 -100A operating at 50Hz and interfaced
with a microcontroller unit and GSM module with a LCD with the wireless communication features over SMS. Within the scope of this project, the prototype model is equipped with a dedicated SIM (Subscriber Identification Module)..