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 U3 1 2 3 4 5 6 7 9 10 14

A1 A2 A3 A4 A5 D6 D7 D8 D9 TE

DOUT

RS

CTC

RTC

15

to RF transmitter

11

LCD1

12

LM016L 13

M145026

TO reader

2 3 4 5 6 7

D2 LED-BIRG D1

OUT IR

8 9 10

LED-BIRG 1 R1(1)

R1

RB0/INT RB1 RB2 RB3/PGM RB4 RB5 RB6/PGC RB7/PGD

RA0/AN0 RA1/AN1 RA2/AN2/VREF-/CVREF RA3/AN3/VREF+ RA4/T0CKI/C1OUT RA5/AN4/SS/C2OUT RC0/T1OSO/T1CKI RE0/AN5/RD RC1/T1OSI/CCP2 RE1/AN6/WR RC2/CCP1 RE2/AN7/CS RC3/SCK/SCL RC4/SDI/SDA MCLR/Vpp/THV RC5/SDO RC6/TX/CK RC7/RX/DT

10k

RD0/PSP0 RD1/PSP1 RD2/PSP2 RD3/PSP3 RD4/PSP4 RD5/PSP5 RD6/PSP6 RD7/PSP7

C3 10u

PIC16F877A

33 34 35 36 37 38 39 40 15 16 17 18 23 24 25 26

from RF reader 11 12 10 9

C1+

C1-

T1IN R1OUT T2IN R2OUT

T1OUT R1IN T2OUT R2IN VS+ VS-

C2+ 4

14 13 7 8 2 6

C5

5

RV1 C7

C7(-)

C6 1u 1k 1u

C2-

1u 19 20 21 22 27 28 29 30

RV1(2)

U2

3

MAX232

7 8 9 10 11 12 13 14

OSC1/CLKIN OSC2/CLKOUT

1u

1 2 3

13 14

1

51%

CRYSTAL

U1

D0 D1 D2 D3 D4 D5 D6 D7

C4

4 5 6

22p

RS RW E

C1 VSS VDD VEE

C2 X1 22p

CIRCUIT DIAGRAM

C2 X1 22p

C1 22p

LCD1 LM016L

8 9 10 1 R1(1)

R1 10k

RD0/PSP0 RD1/PSP1 RD2/PSP2 RD3/PSP3 RD4/PSP4 RD5/PSP5 RD6/PSP6 RD7/PSP7

C3 10u

PIC16F877A

15 16 17 18 23 24 25 26 19 20 21 22 27 28 29 30

DIN

R1

C1

9

6

FROM RF transmitter RV1(2)

7

R2/C2

10

RV1

M145027

1k

D0 D1 D2 D3 D4 D5 D6 D7

A1 A2 A3 A4 A5 D6 D7 D8 D9 VT

7 8 9 10 11 12 13 14

1 2 3 4 5 15 14 13 12 11

RS RW E

RA0/AN0 RA1/AN1 RA2/AN2/VREF-/CVREF RA3/AN3/VREF+ RA4/T0CKI/C1OUT RA5/AN4/SS/C2OUT RC0/T1OSO/T1CKI RE0/AN5/RD RC1/T1OSI/CCP2 RE1/AN6/WR RC2/CCP1 RE2/AN7/CS RC3/SCK/SCL RC4/SDI/SDA MCLR/Vpp/THV RC5/SDO RC6/TX/CK RC7/RX/DT

33 34 35 36 37 38 39 40

4 5 6

RB0/INT RB1 RB2 RB3/PGM RB4 RB5 RB6/PGC RB7/PGD

VSS VDD VEE

2 3 4 5 6 7

OSC1/CLKIN OSC2/CLKOUT

1 2 3

13 14

U2

51%

CRYSTAL

U1

BLOCK DIAGRAM POWER SUPPLY

CARD READER UNIT

GSM

LOAD

P I C 1 6 F 8 7 7 A

LCD DISPLAY

RF RECEIVER

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

D1

1

Power Supply Circuit

VDD

JP2 +4

3

220 VAC

1

C5 470 uF

VIN VOUT GND

2 -

2

VDD

U2 7805 C6 100 uF

R4 220 ohm

C7 0.1 uF D2

3

2 1

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 • Compatibility: avail 28/40 Pin ICs

Microcontroller overview • Operating Speed Max 20 MHz, Voltage-(25.5)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

C2 10 uF

1 3 4 5 6

C3 10 uF

C+ C1C2+ C2V-

C4 10 uF

V+

VCC

R1IN R2IN T1IN T2IN

R1OUT R2OUT T1OUT T2OUT MAX232 U1 GND

TX

13 8 11 10

15

R2IN

10 uF

2

16

C1

12 9 14 7

RX T2OUT

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

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

Why Prepayment – Energy Supplier? • • • • • • • •

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? • 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

Why Prepayment – The Customer?

• • • • • •

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.

THANK YOU