Real time automated load shedding system and fault detection

1. INTRODUCTION

The power consumption is increasing day by day. Load shedding is a method by power supply board to minimize the consumption of power. With the help of this system the process of load shedding of power lines can be made automatic. The whole process is controlled by the microcontroller 89c51 and the real time clock (RTC) PCF 8563 which runs in real time. Here the user can feed the different timings (ON and OFF) for the different power lines, and then according to the entered timings the microcontroller connects and disconnects the power lines automated load shedding system is achieved through real time. In this system two type of faults namely overload and open line faults can also be identified.Automated load shedding system is achieved through real time. However, these automated solutions lack system operating knowledge and are still best-guess methods which typically result in excessive or sufficient load shedding. A load shedding system can provide faster and optimal load relief by utilizing actual operating conditions.

1.1 Objectives:The Load Shedding for the power lines is performed Automated and this process is achieved through Real Time. Microprocessor plays a very important role in this project which is operated to transmit load shed commands as an input to the Relay drivers. It is the best method which typically results in efficient Load Shedding and this system can provide faster and most favorable load relief by utilizing actual operating conditions and knowledge. Turn ON and OFF for the Load Lines can be provided simultaneously at the same time or it can be done at different time.

1.2 Material used: 8051/80c51 Microcontroller, Real Time Clock-PCF 8563, Serial EEPROM, 16*2 LCD, 4*4 Matrixes, Keyboard, Relays.

1.3 Software: Kiel micro vision.2. FUNCTIONAL BLOCK DIAGRAM

MC 89c51 RelayDriversAndRelays Real timeClock PCF 8563 4*4 Matrix Keyboard 16*2 LCD PowerLINESEeprom24c32ADC0809CTHts10pSignal conditionerFig 2.1: Block Diagram

3. FUNCTIONAL DESCRIPTION

In this project a real time clock PCF 8563 is used to monitor the time, which can be interfaced with the microcontroller and it runs in 24 hour format. So on power up first we have to initialize RTC by entering the present time in the form of Hr: Min: Sec and date in the form of Date/month/Year and weekday, once the informations entire are entered, then RTC will start running in real time.If we want to control the lines according to the time, then user has to enter the ON and OFF time for each and every lines which will be stored in the microcontroller memory, then microcontroller reads the time from the RTC and will be checking with the entered timings, if any one of the ON or Off time is matched with the present timing then the controller switches ON or Off particular relay to connect or disconnect the particular line.And also one line is monitored by extracting the current signal through it using the CT HTS10p then it is processed and digitized, then according to the digital signal related to the current signal the microcontroller will come to know that the line is opened or overloaded.

3.1 Current Processing section

Once the mains is connected the loads, then the loads start drawing current, this current taken by the loads is extracted with the help of current transducer HTS 10 P which is connected in series with the phase of the AC mains.

The output of the transducer is a signal of very low voltage (will be in terms of mille volts), which is amplified in two stages using lm 348 amplifier with the gain of 40. Then the amplified voltage is rectified using diode in 4148 and the rectified DC voltage of current signal is applied to the first channel of ADC 0809.

3.2 Analog to Digital Converter (ADC 0809)

ADC 0809 is used to convert the analog input signal to digital value when start of conversion signal is given from microcontroller. This value varies according to the load; the digital value is read from one of the port of the microcontroller.

As the model is turned on, controller will wait for the key press. When the key is pressed load will be turned ON. The controller will then start calculating the units. The available voltage is measured and displayed on the LCD.

4. CIRCUIT DIAGRAM AND ITS REALIZATION

4.1 Power supply circuit

+12 /-12 Volts 500 mA regulated power supply

In mains-supplied electronic systems the AC input voltage must be converted into a DC voltage with the right value and degree of stabilization. Figures below shows the simplest rectifier, filter and stabilization circuits.In these basic configurations the peak voltage across the load is equal to the peak value of the AC voltage supplied by the transformers secondary Winding. For most applications the output ripple produced by these circuits is too high. If a filter capacitor is added after the rectifier diodes The output voltage waveform is improved considerably. The Figure in the circuit uses a center-tapped transformer with four rectifier diodes Single phase AC voltage is stepped down from 230V ac to 15V AC. Using a bridge rectifier, 15V AC supply is rectified and filtered, passed through a linear regulator circuit to get a regulated power supply. With the help of IC 7812 and 7912 linear regulators +-12 V regulated supply is derived.

Fig 4.1.1: +12/-12 volts 500ma regulated power supply circuit

Transformer selected is 15-0-15 volts, 1 Amps. Peak Secondary voltage = 1.4142 * 15 = 21.21 Volts Filter capacitor voltage = 21.21 0.7-0.7 = 19.81 volts The value of the capacitor is selected in such a way that for the designed circuit the ripple of the rectified , filtered dc voltage should have a minimum value; C = 5 I / FV for a 10% ripple factor.Where I= load currentF= Supply frequency,V= Peak secondary supply voltage of transformer The ripple factor must be as much as low as possible for the proper operation of the circuit. Capacitor C2 is used as High frequency filter, bypass all high frequency signals coming on the DCline. IC 7812 is a +ve voltage regulator needs an input voltage minimum of 12+ 2.5 = 14.5 volts for providing regulated voltage. Similarly IC 7912 is a -ve voltage regulator needs an input voltage minimum of 12 + 2.5 = 14.5 volts for providing regulated voltage. IC 7805 is a positive voltage regulator gives a related output voltage of 5 Volts which needs a minimum voltage of 5+2.5 = 7.5 volts as minimum input for its operations.

5Volts, 1.0 Amps Regulated DC Power supply

The +5Volts regulated DC power supply is derived from another regulator IC 7805 whose input voltage is unregulated DC supply of around 15V DC. Unregulated DC voltage is applied to the input pin of the regulator IC after filtering AC component through capacitors. The regulator IC keeps the line and load regulation with in 1% of throughout voltage and once again the capacitors are used to reduce the ac components on the output voltage.

Capacitors C2 and C4 are used for high frequency noise rejection. Capacitor C3 improves the load regulation.

Fig 4.1.2: 5 volts, 1.0 amps regulated power supply circuit4.2 Hall effect Current Transducer and its signal conditioning circuit

The output of the sensor is linearly proportional to the current in the A Hall Effect Current Sensor is a current transformer, which utilizes the Hall Effect. This effect was first observed by Edwin Hall in 1879. He conducted experiments on gold foils wherein he monitored the current flowing from the top to the bottom of a thin rectangular strip. He found that, in the presence of a magnetic field perpendicular to the strip, the electrons were deflected to one side of the gold foil. This caused an excess electrical charge build up, which gave rise to a voltage difference across the right and left side of the foil. This electric field (voltage difference), which is perpendicular to both the magnetic field and the current flow, is called the Hall Voltage. In the absence of a magnetic field, or in the presence of a magnetic field parallel to the strip, there was no voltage difference between the right and left side of the strip.

Fig 4.2.1: Magnetic field showing Hall voltage direction

4.2.1 Theory of Hall Effect

The Hall Effect can be explained by the Lorentz force principle. When a charge moves in a direction perpendicular to an applied magnetic field, it experiences a force defined by the Lorentz Law. The direction of thisForce is perpendicular to the direction of propagation of the charge and that of the external magnetic field.

4.2.2 Operation of Hall Current Sensor

A Hall Current Sensor utilizes the principle of the Hall Effect to detect the current levels. These sensors monitor the gauss level created by a flow of current; they do not measure the actual current flow. The current being measured (through the primary conductor) is passed through a flux-collecting core (which is generally a slotted torpid) that concentrates the magnetic field on the Hall element. The Hall element is a piece of semiconductor material, which produces the Hall voltage proportional to the current flow. The Hall voltage is a low level signal, so generally a low noise high gain amplifier is used to regulate the output of the Hall element. The Hall Element along with the evaluation and regulation circuitry is generally fabricated into a single IC (Integrated Circuit).

Figure shows an example of the output waveform of these sensors. These sensors are radiometric; where the output voltage of the sensor is half that of the supply voltage, when the current in the primary conductor is zero. This voltage is called the quiescent voltage (Vq). When the current flows in the positive direction then the output voltage is greater than Vq, when the current flow reverses, the output voltage is leads thanVq. Saturation occurs when the current exceeds the rating of the sensor.

Fig 4.2.2.1: output waveform of current sensor

In the below figure the voltage generated Vo across the width of the flat, rectangular conductor is directly proportional to both the magnitude of the current through it and the strength of the magnetic field.

Fig 4.2.2.2: Circuit diagram showing relationship between generated voltage Vo and current It makes sense then that if we were to build a device using a Hall-effect sensor where the current through the conductor was pushed by AC voltage from an external circuit and the magnetic field was set up by a pair or wire coils energized by the current of the AC power circuit, the Hall voltage would be in direct proportion to the multiple of circuit current and voltage. The below figure shows the configuration of a closed loop sensor. Here, the output of the Hall IC is amplified and driven through a coil wound around the core. This secondary current, Is, creates a secondary magnetic field in the core. The magnetic flux from the secondary coil is exactly opposite to that generated by the primary conductor and this result in the cancellation of the magnetic flux in the core. The current through the secondary coil is driven through a resistor to measure a voltage that is proportional to the input current Ip.

Fig 4.2.2.3: Closed loop sensor

The selected Hall IC has a quiescent voltage, Voq = 2.5 V which is typically half the supply voltage. It has a sensitivity of 4mV/G. The range of the output voltage for the selected Hall IC is 0.25 V to 4.75 V.

Based on the sensitivity rating and the output voltage we can safely estimate that the IC can sense a flux of 500 G. The selection of the core is based on the size of the primary conductor or the dimension requirements if any.

In the application, a 5Amps Hall effect current transducer is used for reference. The hall sensor operates with a supply voltage of 5 voltages and gives a DC voltage of 2.5Volts for zero current. Since the hall sensor output voltage is 200mv/Amps, voltage developed in the transducer is first amplified, rectified filtered and offset compensated to use it for further application.

Fig 4.2.2.4 Hall current transducer and amplifier circuit

5. SIGNAL CONDITIONING CIRCUIT

The primary and secondary currents of the power transformer are passed through current transformers then transformed to voltage signals by using Hall Effect current transducer as shown in figure. The primary and secondary signals are passed through two buffered, and amplified such that the signals are not distorted because of the loading from subsequent stages .

SW1Relaydriver ckt+5VR3RR2R56VCCU224C324856123GNDVCCSDASCLA0A1A2SW1413+5V230V AC14from MCSW8R1RESISTOR711SW16SW12+5VC3CAPACITORSW215Y116SW5212C2U1PCF856312356781R1RSW68SW10Q1BC548123Y1CRYSTAL12+5VC1SW1510U1AT89C5191819202930314012345678212223242526272810111213141516173938373635343332RSTXTAL2XTAL1GNDPSENALE/PROGEA/VPPVCCP1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7P2.0/A8P2.1/A9P2.2/A10P2.3/A11P2.4/A12P2.5/A13P2.6/A14P2.7/A15P3.0/RXDP3.1/TXDP3.2/INT0P3.3/INT1P3.4/T0P3.5/T1P3.6/WRP3.7/RDP0.0/AD0P0.1/AD1P0.2/AD2P0.3/AD3P0.4/AD4P0.5/AD5P0.6/AD6P0.7/AD7J1CON812345678SW7316X2C1CAP NPSW9SW11K1RELAY SPDT35412SW13C2CAP NP+5VLCD+5VSW17SW PUSHBUTTON129SW34LOADSW4Fig 5.1: Signal conditioning circuit

Operation In this project a Real time clock PCF 8563 is used to monitor the time which can be interfaced with the microcontroller and it runs in 24 hours format. So, on power up first we have to initialize RTC by entering the present time in the form of Hr: Min: Sec and date in the form of Date/month/Year and weekday. Once all the information is entered, the RTC will start running in real time.

If we want to control the load lines according to the time, then user has to enter the ON and OFF time for each and every line which will be stored in the microcontroller memory. Then Microcontroller reads the time from the RTC and will be checking with the entered timings. If any one of the ON or OFF time is matched with the present timings then the controller switches ON or OFF the particular relay to connect or disconnect the particular line.

Here Relay driver is used to drive the relay connected across the power lines and they are switched ON and OFF to connect and disconnect the loads from the power lines according to entered ON and OFF time. A relay is an electro-magnetic switch which is useful if you want to use a low Voltage circuit to switch ON and OFF a light bulb (or anything else) connected to the 220V mains supply.

6. HARDWARE6.1 Power Supply

Main building block of any electronic system is the power supply to provide required power for their operation. For the microcontroller, audio amplifier, keyboard, edge connector +5V, required. And for driving the motor +12V Is required. The power supply provides regulated output voltage of +5V, and non regulated output voltage +12V.Three terminal IC 7805 meets the requirement of +5V regulated. The secondary voltage from the main transformer is rectified by diodes D1-D4 and filtered by capacitor C1. This unregulated dc voltage is supplied to input pin of regulator IC. C2 is an input bypass capacitor and C3 is to improve ripple rejection. The IC used are fixed regulator with internal short circuit current limiting and thermal shut down capability

Fig 7.1.1: Power supply circuit

6.2 RTC PCF 8563

Description

The PCF 8563 is a CMOS real-time clock/calendar optimized for low power consumption. A programmable clock output, interrupt output and voltage-low detector are also provided. All address and data are transferred serially via a two-line bi-directional I2C-bus. Maximum bus speed is 400 kbits/s. the built-in word address register is incremented automatically after each written or read data byte.Features

Provides year, month, day, weekday, hours, minutes and seconds based on 32.768 kHz quartz crystal. Century flag Wide operating supply voltage range: 1.0 to 5.5V Low back-up current; typical 0.25uA at VDD=3.0V and Tamb =25C 400kHz two-wire I2C-bus interface(at VDD=1.8 t0 5.5V) Programmable clock output for peripheral devices: 32.768 kHz, 1024 Hz, 32 Hz and 1 Hz. Alarm and timer functions Voltage-low Detector Integrated oscillator capacitor Internal power-on reset I2C-bus slave address: read A3H; write A2H Open drain interrupt pin. Applications

Mobile telephones Portable instruments Fax machines Battery powered products.

Pin Diagram

PCF8563

18 OSC1 VDD

OSC720 CLKOUT

36 INT SCL

VSS 45 SDA

Fig 7.2.1: Pin diagram of RTC PCF 8563

Functional description

The PCF 8563 contains sixteen 8-bit registers with an auto-incrementing address register, an on-chip 32.768 kHz oscillator with an integrated capacitor, a frequency divider which provides the source clock for the Real-time Clock (RTC), a programmable clock output, a timer, an alarm, a voltage-low detector and a 400 kHz I2C-bus Interface.

All 16 registers are designed as addressable 8-bit parallel registers although not all bits are implemented. The first two registers (memory address 00H and 01) are used as control and/or status registers. The memory addresses 02H through 08H are used as counters for the clock function (Seconds up to year counters). Address locations 09H through 0CH contain alarm registers which define the conditions for an alarm. Address 0DH controls the CLKOUT output frequency. 0EH and 0FH are the timer control and timer registers, respectively.

The Seconds, Minutes, Hours, Days, Months, Years as well as the Minute alarm, Hour alarm and day alarm registers are all coded in BCD format. The Weekdays and Weekday alarm register are not coded in BCD format.

When one of the RTC registers is read the contents of all counters are frozen. Therefore, faulty reading of the clock/calendar during a carry condition is prevented.

6.3 Liquid Crystal Display (LCD) module

Frequently a AT89C51 program must interact with the outside world using input and output devices that devices that communicate directly with a human being. One of the most common output devices used is a LCD. Some common LCDs are 16x2 and 20x2 displays, which mean 16 characters per 2 line and 20 characters per lines, respectively.Fortunately. Standards exist which allow us to communicate with vast majority of LCD. The Standard is referred to as HD44780U, which refer to the controller chip, which receivers data from microcontroller and communicates directly with LCD.HD44780UThe 44780 standard requires 3 control lines as 4 or 8 1/0 lines for the data bus the user may select whether the LCD is to operate with 4-bit data bus or 8-data bus. The 3 control lines are EN, RS and RW. The EN line is called called Enable. This control line is used to tell LCD that we are sending it Data. To send data the, program should first send High in this line and then set the other two control line and put data on the data bus. When other lines are ready, EN should be made LOW. The RS line is Register selector line . when RS is LOW , the data is to be treated as a command or special instruction (such as CLEAR SCREEN, ETC). When RS is HIGH, the data being sent is text data that should be displayed on the screen. The RW line is read/write control line. When it is LOW, the information on data bus is being written to LCD. When RW is HIGH, the program is effectively querying the LCD with the instruction Get LCD status.A more robust method is to use GET LCD STATUS command to determine if the LCD is the last really use the LCD, must initialize and configure it. This is accomplished by sending a number of instructions to the LCD. The first instruction will be to specify whether we are using 4 or 8- line data bus. Sending a 38h command to the LCD dose this. Before we send the command the RS line should be made low. We then send the 0Eh command to turn the LCD ON. Lastly we send the 06h command so that every time we send a character the cursor automatically moves right.NOTE: the LCD can be cleared using the 01h command.

CURSOR POSITIONINGThe 44780 contain a certain amount of memory, which is assigned to display. All text we write to 44780 is stored in this memory, and the 44780 subsequently reads this memory to display the text on LCD itself. This memory maps is shown below.DISPLAY In the above memory map, area up to 0F and 4F is the visible display. As one can see, it measures 16 characters per 2 lines. The numbers in each box in memory address that corresponds to that on screen. Thus the Set Cursor Position instruction 80h tell the LCD to position the cursor. Adding the cursor position to 80h does these sets the cursor to the required position on the screen.

PIN Assignment

PIN NO.SYMBOL

1Vss

2VDD

3V0

4RS

5R/W

6E

7DBO

8DB1

9DB2

10DB3

11DB4

12DB5

13DB6

14DB7

15LED-(K)

16LED-(A)

6.4 Interfacing keyboard

A matrix keyboard is a commonly used input device when more than eight keys are necessary, rather than a row of keys as illustrated. A matrix keyboard reduces the number of connections, thus the number of interfacing devices required. For example, a keyboard with 16 keys, arranged in a 4*4 matrix requires eight lines from the Microcontroller to make all the connections instead of 16 lines if the keys are connected in a linear format. When a key is pressed, it shorts one row and column; otherwise, the row and the column do not have any connection. The interfacing of a matrix keyboard requires two ports; one output port and the input port. Rows are connected to the output port, and the columns are connected to the input port. They are capable of interfacing a matrix keyboard as large as 64 keys in eight columns and eight rows. In our project we are using 4*3 matrix keyboard of 12 keys. In which columns are connected to port 2 [P2] and rows are connected to port 0 [P0].

Key sensing logic

Initially all the column lines will be in high state and each rows are grounded by making the row port lines low one by one. If we are in say first row it will check whether any key is pressed by reading the column port. If any one of the first row is pressed then the particular column will get low level if in the first row then the column number which gets the low signal will be the key number. For example if we start the column number from zero then the first key identified as number zero. If the none of the key is pressed in row 1 then controller will ground the next row in this row .If any key is pressed it will identify the column number and adds number 4 once to get exact to get exact key number if it is in the row 3 it add number 4 two times to the column number to get the correct key.

Interfacing keyboard

Fig 7.4.1: Interfacing keyboard

6.5 Relay Driver

230 AC

AC LoadBC 5485V VCC

Fig 7.5.1: Relay driverHere relay driver is used to drive the relays connected across the power lines, and they are switched ON and Off to connect and disconnect the loads from the power lines according to the entered ON and Off time.

6.6 Serial EEPROM Features

Low power CMOS technology maximum write current 3 ma at 5.5v maximum read current 400micro amps at 5.5v Standby current 100na typical at 5.5v 2-write serial interface bus, I2C compatible Cascadable for up to eight devices Self-timed ERASE/WRITE cycle 64-byte page-write mode available 5ms max write protect for entire array Hardware write protect for entire array Schmitt trigger inputs for noise suppression 100,000 erase/write cycles guaranteed Electrostatic discharge protection>4000v Data relation> 200 years 8-pins PDIP and SOIC (208ml) packages Temperature ranges: -Industrial (I)-400 c to +850 c -Automotive (E) - 400 c to +1250 cDescription

The Microchip Technology Inc. 24AA256/24LC256 (24x256*) is a 32k x8 (256k bit) Serial Electrically Erasable PROM, capable of operation across a board voltage range (1.8v to 5.5v). it has been developed for advanced, low power applications such as personal communications or data acquision. This device also has a page-write capability of up to 64 bytes of data. This device is capable of both random and sequential reads allow up to 256k boundary. Functional address lines allow up to eight devices on the same bus, for up to 2 Mbit address space. This device is available in the standard 8-pin plastic DIP, and 8-pin SOIC (208 mil) packages. PIN DescriptionsFig 7.6.1: Pin description of serial EEPROM

A0,A1,A2 Chip are Address Inputs The A0,A1,A2 inputs are used by the 24x256 for multiple device operation. The levels on these inputs are compared with the corresponding bits in the slave address .The chip is selected if the compare is true.Up to eight devices may be connected to the same bus by using different chip is select bit combinations. If left unconnected, these inputs will be pulled down internally to Vss.

SDA Serial Data

This is a bi-directional pin used to transfer addresses and data into and data out of the device. It is an open drain terminal, therefore, the SDA bus requires a pull up resistor to Vcc (typical 10 k ohm for 100 khz, 2k ohm for 400 khz)SCL serial clockThis input is used to synchronize the data transfer from and to the device.

WPThis pin can be connected to either Vss, Vcc or left floating. An internal pull-down on this pin will keep the device in the unprotected state if left floating. If tied to Vss or left floating, normal memory operation is enabled (read/write the memory 0000-7FFF).If tied to Vcc, WRITE operations are inhibited. Read operation as are not affected.Functional description

The 24xx256 support a bi-directional 2-write bus and data transmission protocol. A device that sends data onto the bus is defined as a transmitter, and a device receiving data as a receiver. The bus must be controlled by a master device which generates the serial clock (SCL), controls the bus access, and generates the START and STOP conditions while the 24xx256 works as a slave. Both master and slave can operate as a transmitter or receiver, but the master device determines which mode is activated.Bus characteristics

The following bus protocol has been defined: Data transfer may be initiated only when the bus is not busy. During data transfer, the data line must remainstable whenever the clock line-is HIGH/ changes in the data line while the clock line is high will be interpreted as a START or STOP condition.Accordingly, the following bus conditions have been defined.Bus not Busy (A) Both data and clock lines remains HIGH> Start Data Transfer(B) A HIGH to LOW, transmission of the SDA line while the clock (SCL) is high determines START condition. All commands must be preceded by a START condition. Data Valid (D) The state of the data represents valid data when, after a START condition, the data line is stable for the duration of the HIGH period of the clock signal.

7. FLOW CHARTstart

Is req to set the present time ?

Initialise RTCYes

No

Is req to enter the timings for ON and OFF?

Enter different ON and OFF timings for different linesYesyYes

Record all entered timings in EEPROM

Read the present time from RTC

No

Is line open ?Is time matched with any ON and OFF time ?NoSwitch ON or Switch OFF the corresponding time matched lineIs line over loadedDisplay Line openYes

YesNo

Display Over loadYes

No Fig 8.1: Flow chart8. ADVANTAGES, DISADVANTAGES AND APPLICATIONS

Advantages

Load shedding is made automated and operation can be controlled. Simple circuit formation. No operation is required for the full 24 hours a day. Once the time is fed for load shedding, the system can operate independently. Requires less maintenance. Load lines can be turned ON /OFF simultaneously at the same time or at different time. The system is secured.

Disadvantages

Since Microcontroller controls the whole system, if any fault occurs in it the whole system fails.

Applications To provide automated load shedding for the power lines.

Can be used in Industries for automation purposes.

9. RESULT

The load shedding can be done according to time. Can maintain time limit for load shedding. Turn ON and OFF the load simultaneously at the same time Turn ON and OFF the load at the different time.

TEST RESULTSTATIONDATEDAYOFF TIMEON TIMESTATUS

STATION 102/05/2011MONDAY12:30:2212:50:15SUCCESSFUL

STATION 202/05/2011MONDAY13:15:1513:30:30SUCCESSFUL

STATION 303/05/2011TUESDAY10:30:3010:55:55SUCCESSFUL

STATION 403/05/2011TUESDAY09:15:0009:59:00SUCCESSFUL

STATION 105/05/2011THURSDAY12:24:1012:35:45SUCCESSFUL

STATION 305/05/2011THURSDAY15:02:0015:05:44SUCCESSFUL

STATION 407/05/2011SATURDAY14:09:2214:10:30FAULT DISPLAYED(OVER LOAD)

STATION 407/05/2011SATURDAY14:30:0014:33:26FAULT DISPLAYED(OPEN LINE)

10. CONCLUSION

Load shedding serves as the ultimate guard that protects the power system from a disturbance-induced collapse. Since we are operating A.C power lines, we should not keep any line open. We can conclude that, with the help of this system the load shedding for the power lines can be made Automatic according to the entered timings for different areas along with fault analysis.

Scope for Future WorkIn this project the load shedding is mainly by using Microcontroller and in future GSM Modem (Group Special Mobile) can also be added so that this automated operation can be controlled from far away places.

Dept. of E&E, SKIT Bangalore -90 2010-2011Page 25