AN EFFICIENT MONITERING OF SUBSTATION USING RF

ANALOG TO DIGITAL CONVERTER

SUBSTATIONYPRCET20-02-20131)Power from Generating Units Delivered to Costumers through substation

2) The Main purpose of substations is to vary voltage levels to meet costumer requirements.

3)Sub stations plays an important role in maintaining power quality

2SUBSTATION YPRCET20-02-2013The level of current and voltage may vary drastically due to increase in temperature at the distribution transformer.

The ultimate objective is to monitor the electrical parameters continuously and hence to Guard the burning of Distribution Transformer.3 PROTECTION OF SUBSTATION YPRCET20-02-20131)VOLTAGE PROTECTION

2)CURRENT PROTECTION

3)TEMPERATURE PROTECTION4The system contains two main sections

1)substation unit called Transmitter unit2)Main station called controlling unit

5 Substation unitYPRCETPOWERSUPPLYMICROCONTROLLERADCTEMPERATURE SENSORCURRENTSENSORVOLTAGESENSORRELAYLOADSTRANSFORMERENCODERRF TRANSMITTER6Control unitMICROCONTROLLERPOWER SUPPLYRFRECEIVERDECODERLCDMICROCONTROLLERSPOWER SUPPLY RF TRANSMITTERRF RECEIVERENCODERDECODERTEMPERATURE SENSORCURRENT AND VOLTAGE SENSORRELAYADC

HARDWARE COMPONENTSResistorsCapacitorsInductorsDiodesLed'sVoltage regulatorsTransistorsOscillatorSwitchesVoltage variacThermistor

Hardware elements 230 volts AC is stepped down to 5v to suit microcontroller and 12v to operate Relay using step down transformer and voltage regulatorTo make the system as automatic we use microcontroller to handle the operationsA Micro controller consists of a powerful CPU tightly coupled with memory, various I/O interfaces such as serial port, parallel port timer or counter, interrupt controller, data acquisition interfaces-Analog to Digital converter, Digital to Analog converter, integrated on to a single silicon chip

DESIGN

12345678910111213141516171819204039383736353433323130292827262524232221P1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7RST(RXD)P3.0(TXD)P3.1(T0)P3.4(T1)P3.5XTAL2XTAL1GND(INT0)P3.2(INT1)P3.3(RD)P3.7(WR)P3.6VccP0.0(AD0)P0.1(AD1)P0.2(AD2)P0.3(AD3)P0.4(AD4)P0.5(AD5)P0.6(AD6)P0.7(AD7)EA/VPPALE/PROGPSENP2.7(A15)P2.6(A14)P2.5(A13)P2.4(A12)P2.3(A11)P2.2(A10)P2.1(A9)P2.0(A8) 8051(8031)MICRO CONTROLLER

MICRO CONTROLLER ARCHITECTUREInternal ROM or EPROM (8751) of 0(8031) to 4K (89C51)Internal RAM of 128 bytes:Four register banks, each containing eight registersSixteen bytes, which maybe addressed at the bit levelEighty bytes of general- purpose data memoryThirty two input/output pins arranged as four 8-bit ports:p0-p3Two 16-bit timer/counters: T0 and T1Full duplex serial data receiver/transmitter: SBUFControl registers: TCON, TMOD, SCON, PCON, IP, and IETwo external and three internal interrupts sources.Oscillator and clock circuits8051 FEATURES RAM ROMI/O PortTimerSerial COM PortMicrocontrollerCPUA smaller computerOn-chip RAM, ROM, I/O ports...ExampleMotorolas 6811, Intels 8051, Zilogs Z8 and PIC 16XA single chip:8051 OVERVIEWPins of 80511/4Vccpin 40Vcc provides supply voltage to the chip. The voltage source is +5V.GNDpin 20groundXTAL1 and XTAL2pins 19,18

XTAL Connection to 8051

C230pFC130pFXTAL2XTAL1GNDUsing a quartz crystal oscillatorWe can observe the frequency on the XTAL2 pin. Pins of 80512/4RSTpin 9resetIt is an input pin and is active highnormally low.The high pulse must be high at least 2 machine cycles.It is a power-on reset.Upon applying a high pulse to RST, the microcontroller will reset and all values in registers will be lost.Reset values of some 8051 registers Pins of 80513/4/EApin 31external accessThere is no on-chip ROM in 8031 and 8032 .The /EA pin is connected to GND to indicate the code is stored externally./PSEN ALE are used for external ROM.For 8051, /EA pin is connected to Vcc./ means active low./PSENpin 29program store enableThis is an output pin and is connected to the OE pin of the ROM.Pins of 80514/4ALEpin 30address latch enableIt is an output pin and is active high.8051 port 0 provides both address and data.The ALE pin is used for de-multiplexing the address and data by connecting to the G pin of the 74LS373 latch.I/O port pinsThe four ports P0, P1, P2, and P3.Each port uses 8 pins.All I/O pins are bi-directional.Hardware Structure of I/O Pin Each pin of I/O portsInternal CPU buscommunicate with CPUA D latch store the value of this pinD latch is controlled by Write to latchWrite to latch1write data into the D latch2 Tri-state bufferTB1: controlled by Read pinRead pin1really read the data present at the pinTB2: controlled by Read latchRead latch1read value from internal latchA transistor M1 gateGate=0: openGate=1: closeOther PinsP1, P2, and P3 have internal pull-up resisters.P1, P2, and P3 are not open drain.P0 has no internal pull-up resistors and does not connects to Vcc inside the 8051.P0 is open drain.Compare the figures of P1.X and P0.X. However, for a programmer, it is the same to program P0, P1, P2 and P3.All the ports upon RESET are configured as output.RegistersABR0R1R3R4R2R5R7R6DPHDPLPCDPTRPCSome 8051 16-bit RegisterSome 8-bitt Registers of the 8051Memory mapping in 8051

ROM memory map in 8051 family0000H0FFFH0000H1FFFH0000H7FFFH8751AT89C518752AT89C524kDS5000-328k32kfrom Atmel Corporationfrom Dallas SemiconductorRAM memory space allocation in the 80517FH30H2FH20H1FH17H10H0FH07H08H18H00HRegister Bank 0(Stack) Register Bank 1 Register Bank 2Register Bank 3Bit-Addressable RAMScratch pad RAM

Timer :

TMOD Register: Gate : When set, timer only runs while INT(0,1) is high.C/T : Counter/Timer select bit.M1 : Mode bit 1.M0 : Mode bit 0.

To make the microcontroller to communicate with computer we use MAX232 which converts source code to computer understandable code.

MAX 232

Liquid crystal displays (LCD s) have materials which combine the properties of both liquids and crystals. Rather than having a melting point, they have a temperature range within which the molecules are almost as mobile as they would be in a liquid, but are grouped together in an ordered form similar to a crystal.LIQUID CRISTAL DISPLAY(LCD)

The LCD s wont generate light and so light is needed to read the display. By using backlighting, reading is possible in the dark. The LCDs have long life and a wide operating temperature rangeTo send any command from table 2 to the LCD, make pin RS=0. For data, make RS=1.Then place a high to low pulse on the E pin to enable the internal latch of the LCD. When sufficient voltage is applied to the electrodes, the liquid crystal molecules would be aligned in a specific direction.RF transmitters are electronic devices that create continuously varying electric current, encode sine waves, and broadcast radio wavesRF transmitters use oscillators to create sine waves, the simplest and smoothest form of continuously varying waves, which contain information such as audio and videoSelecting RF transmitters requires an understanding of modulation methods such as AM and FM

RF TRANSMITTERAmplitude modulation (AM) causesthe base band signalto vary the amplitude or height of the carrier wave to create the desired information content. Frequency modulation (FM) causes the instantaneous frequency of a sine wave carrier to depart from the center frequency by an amount proportional to the instantaneous value of the modulating signal.

RF ENCODERThe 212 encoders are a series of CMOS LSIs for remote control system applications.

They are capable of encoding information which consists of N address bits and 12_N data bits

RF RECEIVER RF receivers are electronic devices that separate radio signals from one another and convert specific signals into audio, video, or data formats. RF receivers use an antenna to receive transmitted radio signals and a tuner to separate a specific signal from all of the other signals that the antenna receives.

RF receivers vary in terms of performance specifications such as sensitivity, digital sampling rate, measurement resolution, operating frequency, and communication interfac

CURRENT TRANSFORMERCURRENT TRANSFORMERS ARE USED TO MEASURE HIGH CURRENTS

VOLTAGE TRANSFORMERHIGHVOLTAGES ARE STEPPEDDOWN TO LOWVOLTAGE FOR RELIABLE MEASUREMENT

SOURCE CODE

TO OPERATE THE SYSTEM THAT IS CONTROLLED BY MICROCONTROLLER WE WRITE A NECESSARY SOURCE CODE TO SUIT THE DESIRED APPPLICATION.THE CODE IS WRITTEN IN C USING KELI

Embedded Controller

RXD

TXD

RXD

TXD

2

3

5

GND

MAX 232

CONTROL

TRI- STATE

Output

Latch

SAR

CONTROL LOGIC

8 x 1

analog

MUX

MUX

address

register