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/AN0 2 RA1/AN1 3 RA2/AN2/VREF-/CVREF 4 RA4/T0CKI/C1OUT 6 RA5/AN4/SS/C2OUT 7 RE0/AN5/RD 8 RE1/AN6/WR 9 RE2/AN7/CS 10 OSC1/CLKIN 13 OSC2/CLKOUT 14 RC1/T1OSI/CCP2 16 RC2/CCP1 17 RC3/SCK/SCL 18 RD0/PSP0 19 RD1/PSP1 20 RB7/PGD 40 RB6/PGC 39 RB5 38 RB4 37 RB3/PGM 36 RB2 35 RB1 34 RB0/INT 33 RD7/PSP7 30 RD6/PSP6 29 RD5/PSP5 28 RD4/PSP4 27 RD3/PSP3 22 RD2/PSP2 21 RC7/RX/DT 26 RC6/TX/CK 25 RC5/SDO 24 RC4/SDI/SDA 23 RA3/AN3/VREF+ 5 RC0/T1OSO/T1CKI 15 MCLR/Vpp/THV 1 U1 PIC16F877A D 7 14 D 6 13 D 5 12 D 4 11 D 3 10 D 2 9 D 1 8 D 0 7 E 6 R W 5 R S 4 V S S 1 V D D 2 V E E 3 LCD1 LM016L RV1(2) 51 % RV1 1k X1 CRYSTAL C1 22p C2 22p R1(1) _R1 10k C3 10u D1 LED-BIRG D2 LED-BIRG OUT IR T1IN 11 R1OUT 12 T2IN 10 R2OUT 9 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 A1 1 A2 2 A3 3 A4 4 A5 5 D6 6 D7 7 D8 9 D9 10 TE 14 DOUT 15 RS 11 CTC 12 RTC 13 U3 M145026 to RF transmitter

CIRCUIT DIAGRAM RA0/AN0 2 RA1/AN1 3 RA2/AN2/VREF-/CVREF 4 RA4/T0CKI/C1OUT 6 RA5/AN4/SS/C2OUT 7 RE0/AN5/RD 8 RE1/AN6/WR 9 RE2/AN7/CS 10 OSC1/CLKIN 13 OSC2/CLKOUT 14 RC1/T1OSI/CCP2 16 RC2/CCP1 17 RC3/SCK/SCL 18 RD0/PSP0 19 RD1/PSP1 20 RB7/PGD 40 RB6/PGC 39 RB5 38 RB4 37 RB3/PGM 36 RB2 35 RB1 34 RB0/INT 33 RD7/PSP7 30 RD6/PSP6 29 RD5/PSP5 28 RD4/PSP4 27 RD3/PSP3 22 RD2/PSP2 21 RC7/RX/DT 26 RC6/TX/CK 25 RC5/SDO 24 RC4/SDI/SDA 23 RA3/AN3/VREF+ 5 RC0/T1OSO/T1CKI 15 MCLR/Vpp/THV 1 U1 PIC16F877A D 7 1 4 D 6 1 3 D 5 1 2 D 4 1 1 D 3 1 0 D 2 9 D 1 8 D 0 7 E 6 R W 5 R S 4 V S S 1 V D D 2 V E E 3 LCD1 LM016L RV1(2) 5 1 % RV1 1k X1 CRYSTAL C1 22p C2 22p R1(1) _R1 10k C3 10u FROM RF transmitter A1 1 A2 2 A3 3 A4 4 A5 5 D6 15 D7 14 D8 13 D9 12 VT 11 _R2/C2 10 C1 7 R1 6 DIN 9 U2 M145027

BLOCK DIAGRAM P I C 1 6 F 8 7 7 A 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

Power Supply Circuit

VDD VDD C7 0.1 uF JP2 220 VAC 1 2 - + D1 1 4 3 2 U2 7805 1 3 2 VIN G N D VOUT C6 100 uF C5 470 uF R4 220 ohm D2 LED

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

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

VDD RX TX T2OUT R2IN U1 MAX232 13 8 11 10 1 3 4 5 2 6 12 9 14 7 16 15 R1IN R2IN T1IN T2IN C+ C1-C2+ C2-V+ V-R1OUT R2OUT T1OUT T2OUT VC C GN D C1 _{10 uF} C4 10 uF C3 10 uF C2 10 uF

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

AT COMMANDS

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

standard 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

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 – Energy

Supplier?

Why Prepayment – Energy Supplier?

• 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

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.