Prepaid Energy Meter Using Pic Microcontroller

PREPAID ENERGY METER USING PIC MICROCONTROLLER

INTRODUCTION• The scope of the project work is to introduce advanced

technology in converting dc voltage in to ac voltage and introducing prepaid energy metering concept.

• The energy meter used in this project work produces pulses according to the load and this meter is converted as prepaid energy meter using smart card, hence this meter can be called smart energy meter.

• This kind of smart energy meters also can be installed at each and every house, where the state electricity department going to supply the conventional energy. Now a days energy Measurement and electric energy pilferage detection has become prime importance for the state electricity department.

INTRODUCTION

• With the help of this project work lot of Manpower can be reduced and power pilferage can be controlled.

• The overall system can be called as AMR (Automatic Meter reading) system, the main advantage of AMR system is that the consumed energy price can be calculated and at the same time price (amount in rupees) can be displayed automatically.

• Finally the simplest form of smart metering is a display meter, which allows consumers to monitor consumption in money terms rather than kWh.

Outlook• Monitor Unit of Split Meter

LCD

Button

IC card socket

CIRCUIT DIAGRAM

RA0/AN02

RA1/AN13

RA2/AN2/VREF-/CVREF4

RA4/T0CKI/C1OUT6

RA5/AN4/SS/C2OUT7

RE0/AN5/RD8

RE1/AN6/WR9

RE2/AN7/CS10

OSC1/CLKIN13

OSC2/CLKOUT14

RC1/T1OSI/CCP2 16

RC2/CCP1 17

RC3/SCK/SCL 18

RD0/PSP0 19

RD1/PSP1 20

RB7/PGD 40RB6/PGC 39

RB5 38RB4 37

RB3/PGM 36RB2 35RB1 34

RB0/INT 33

RD7/PSP7 30RD6/PSP6 29RD5/PSP5 28RD4/PSP4 27RD3/PSP3 22RD2/PSP2 21

RC7/RX/DT 26RC6/TX/CK 25

RC5/SDO 24RC4/SDI/SDA 23

RA3/AN3/VREF+5

RC0/T1OSO/T1CKI 15

MCLR/Vpp/THV1

U1

PIC16F877A

D7

14D

613

D5

12D

411

D3

10D

29

D1

8D

07

E6

RW

5R

S4

VSS

1

VD

D2

VEE

3

LCD1LM016L

RV1(2)

51%

RV1

1k

X1

CRYSTAL

C122p

C222p

R1(1) R1

10k

C310u

D1

LED-BIRG

D2

LED-BIRG

OUT IR

T1IN11

R1OUT12

T2IN10

R2OUT9

T1OUT 14

R1IN 13

T2OUT 7

R2IN 8

C2+

4

C2-

5

C1+

1

C1-

3

VS+ 2

VS- 6

U2

MAX232

C4

1u

C5

1u

C6

1u

C7

1u

C7(-)

from RF reader

TO reader

A11

A22

A33

A44

A55

D66

D77

D89

D910

TE14

DOUT 15

RS 11

CTC 12

RTC 13

U3

M145026

to RF transmitter

CIRCUIT DIAGRAM

RA0/AN02

RA1/AN13

RA2/AN2/VREF-/CVREF4

RA4/T0CKI/C1OUT6

RA5/AN4/SS/C2OUT7

RE0/AN5/RD8

RE1/AN6/WR9

RE2/AN7/CS10

OSC1/CLKIN13

OSC2/CLKOUT14

RC1/T1OSI/CCP216

RC2/CCP117

RC3/SCK/SCL18

RD0/PSP019

RD1/PSP120

RB7/PGD40

RB6/PGC39

RB538

RB437

RB3/PGM36

RB235

RB134

RB0/INT33

RD7/PSP730

RD6/PSP629

RD5/PSP528

RD4/PSP427

RD3/PSP322

RD2/PSP221

RC7/RX/DT26

RC6/TX/CK25

RC5/SDO24

RC4/SDI/SDA23

RA3/AN3/VREF+5

RC0/T1OSO/T1CKI15

MCLR/Vpp/THV1

U1

PIC16F877A

D7

14D

613

D5

12D

411

D3

10D

29

D1

8D

07

E6

RW

5R

S4

VS

S1

VD

D2

VE

E3

LCD1LM016L

RV1(2)

51%

RV1

1k

X1

CRYSTAL

C122p

C222p

R1(1) R1

10k

C310u

FROM RF transmitterA11

A22

A33

A44

A55

D615

D714

D813

D912

VT11

R2/C210

C17

R16

DIN9

U2

M145027

BLOCK DIAGRAM

PIC16F877A

CARD READER UNIT

GSM

POWER SUPPLY

RF RECEIVER

LCD DISPLAY

LOAD

BLOCK DIAGRAM EXPLANATION• In this system the user has to purchase an EEPROM based recharge

card and it should be inserted in the slot provided on prepaid energy meter kit. After inserting the recharge card into the system, Then the system will be loaded with specific units as per the recharge card value. A 16X2 LCD is provided to read units available. Here the system is connected with three to four loads. If the load increases in the system, current also increases and is calculated by an ADC and its corresponding count is also calculated. Whenever the count value reaches one thousand, 1unit is decremented from EEPROM and these values are displayed on LCD.

• An EEPROM is provided on the board to store the updated recharge units and energy meter pulse count. At every instant the count value and units values are stored in EPROM so that the data will not be lost even in power failure cases. When 1 unit is decremented from EEPROM the system will give a beep sound. If recharge value below 10 units the GSM modem send alert message to owner .When the recharged units become zero on power consumption, the system shutdown all the loads connected to it by giving a continuous beep sound.

Hardware Components

• Power supply[5v]• PIC16F877A microcontroller• GSM modem• Current Transformer• Voltage Transformer• Max232 – serial communication

Power Supply Circuit

V D D

V D D

C 70 . 1 u F

J P 2

2 2 0 V A C

12

- +

D 1

14

32

U 27 8 0 5

1

3

2V I N

GND

V O U T

C 61 0 0 u F

C 54 7 0 u F

R 42 2 0 o h m

D 2

L E D

Power Supply – Circuit Description

• The operation of power supply circuits built using filters, rectifiers, and then voltage regulators. Starting with an AC voltage, a steady DC voltage is obtained by rectifying the AC voltage, Then filtering to a DC level, and finally, regulating to obtain a desired fixed DC voltage. The regulation is usually obtained from an IC voltage regulator Unit, which takes a DC voltage and provides a somewhat lower DC voltage, Which remains the same even if the input DC voltage varies, or the output Load connected to the DC voltage changes.

About Microcontroller

• PIC16F877A microcontroller is used for this project

• It is 8-bit Microcontroller• System is RISC Architecture• It has Small set of Instruction set• It has 35-Instructions only• Compatibility: avail 28/40 Pin ICs

Microcontroller overview

• Operating Speed Max 20 MHz, Voltage-(2-5.5)v

• Memory: Flash Program 8Kx14 Words, RAM 368 Bytes, EEPROM Data Memory 256 Bytes

• Low power, High speed Flash/EEPROM Technology

Features of Microcontroller

• It has 5 Ports for Internal and External usage• It has on chip Timers. 3 Timers are avail• It has in built Analog to Digital Converter• In built Multiplexer availability for signal

Selection• It has serial as well as Parallel Communication

facilities• In built Capture, Compare and Pulse width

modulation

UART pins inPIC16f877A

• The UART always transmits data on pin RC6/TX• The UART always receives data on pin RC7/RX• The RS-232 standard defines lots of other

signals other than TX and RX used for handshaking.

Voltages

• The UART input/output uses 0V for logic 0 and 5V for logic 1.

• The RS-232 standard (and the COM port) use +12V for logic 0 and –12V for logic 1.

• To convert between these voltages levels we need an additional integrated circuit (such as Maxim’s MAX232).

MAX232

V D D

R X

TX T2 O U T

R 2 I N

U 1M A X2 3 2

1 38

1 11 0

1345

26

1 291 47

1615

R 1 I NR 2 I NT1 I NT2 I N

C +C 1 -C 2 +C 2 -

V+

V -

R 1 O U TR 2 O U TT1 O U TT2 O U T

VC

CG

ND

C 1 1 0 u F

C 41 0 u F

C 31 0 u F

C 21 0 u F

GSM modem• A GSM modem is a wireless modem that works with a

GSM wireless network. • A wireless modem behaves like a dial-up modem. The

main difference between them is that a dial-up modem sends and receives data through a fixed telephone line while a wireless modem sends and receives data through radio waves.

• A GSM modem can be an external device or a PC Card / PCMCIA Card. Typically, an external GSM modem is connected to a computer through a serial cable or a USB cable.

• Like a GSM mobile phone, a GSM modem requires a SIM card from a wireless carrier in order to operate.

AT COMMANDS

• computers use AT commands to control modems. Both GSM modems and dial-up modems support a common set of standard AT commands.

• GSM modems support an extended set of AT commands.

Operations

• Reading, writing and deleting SMS messages.• Sending SMS messages.• Monitoring the signal strength.• Monitoring the charging status and charge

level of the battery.• Reading, writing and searching phone book

entries.

GSM phone or modem supports SMS text mode

Check if your GSM phone or modem supports SMS text mode

To check if your modem supports this text mode, you can try the following command:

AT+CMGF=1 <ENTER>

If the modem responds with "OK" this mode is supported.

Software Tools

• MPLAB IDE• Hitech c compiler• Win pic programmer• ORCAD design

MPLAB IDE

Winpic800 Programmer

Prepaid meters advantages• High accuracy over a wide current dynamic range• Reliability and robustness• Flexibility of design• Automatic Meter Reading (AMR)• More easily enable new functionalities• Multi tariff billing• Tamper proofing• Prepayment meters• Power out range detection• Power factor detection• Easily reconfiguration, upgrade • Do not use gears that wear out or magnets that saturate with DC

current• Do not require precision mechanics or have large tolerance variations

over temperature

• Pay before use• Keep customers on supply• Recover money owed (debt)• Lower Overheads• No bill production• No bill distribution• No need to chase payments• No further actions such as disconnections

Why Prepayment – EnergySupplier?

Why Prepayment – EnergySupplier?

• Social Acceptability• Customer responsible for Disconnection• Load and Demand Side Management• Limit load• Load based• Time based

Why Prepayment – The Customer?

• >80% Mobile phones used in India are prepaid• Flexible Payment Solution• Pay to suit your income status• Daily, Weekly , Monthly Budgeting• Show true cost of consumption and money Left• Reduce consumption when income is tight– make money last• Reduce waste – conserve energy

• No Bills• No hidden surprises• No having to find the money• No billing errors• No socially unacceptable• disconnections

Why Prepayment – The Customer?

CONCLUSIONS

• Advanced electricity meters that generate consumption data enabling customers to see when they are using energy, to manage that use more efficiently

• To save money by adjusting energy use in response to price signals.

• To save money, the consumed energy corresponding price is displayed for the consumer benefits.

• This project work has been taken up which serves the purpose of energy monitoring and controlling by implementing prepaid system.

• It is hoped that this work helps the electrical engineers for better energy management and its utility in the distribution system for economic liability of the electrical companies.

THANK YOU