Here we learn programmed real time load switching using rtc

1. PROGRAMMABLE LOAD SHEDDING TIME
MANAGEMENT FOR UTILITY DEPARTMENT
Under the Guidance of
Asst.Prof.Ghongade.Prashant
Presented by
Padmaraj (3GN14EE027)
Mukund (3GN15EE025)
Jagdish (3GN15EE014)
Sachin (3GN16EE413)
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2. CONTENTS:
 INTRODUCTION
 PROJECT BLOCK DIAGRAM
 POWER SUPPLY
 HARDWARE COMPONENT
 WORKING OF PROJECT
 SOFTWARE REQURIEMENTS
 ADVANTAGES
 FUTURE SCOPE
 CONCLUSION
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3. Load shedding is what electric utilities do when there is a huge demand for
electricity that exceeds the supply. Thus in a distribution system it needs to
be precisely controlled for specific period of time. Programmable load
shedding time management system is a reliable circuit that takes over the
manual task of switch ON/OFF the electrical devices with respect to time.
It uses real time clock (RTC) interfaced to a microcontroller of 8051
family. While the set time equals to the real time, then microcontroller
gives command to the corresponding relay to turn ON the load and then
another command to switch OFF as per the program. Multiple ON/OFF
time entry is the biggest advantage with this project. A matrix keypad
helps entering the time. A 7-sement display is interfaced to the
microcontroller to display time.
INTRODUCTION
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4. PROJECT BLOCK DIAGRAM
Fig. 1 :Block diagram of Programmable Load Shedding.
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5. HARDWARE COMPONENTS
POWER SUPPLY BLOCK
VOLTAGE REGULATOR (LM 7805)
MICROCONTROLLER (AT89S52/AT89C51)
DS1307 RTC
MATRIX KEYPAD
RELAY
SEVEN SEGMENT
BC547
RESISTORS
CAPACITORS
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6. MICROCONTROLLER
 It is a smaller computer
 Has on-chip RAM, ROM, I/O ports...
RAM ROM
I/O
Port
Timer
Serial
COM
Port
Microcontroller
CPU
A single chip
Fig.2:Structure of Microcontroller
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7. INTERNAL STRUCTURE OF A MICRO CONTROLLER-AT89S52/51
CPU
On-chip
RAM
On-chip
ROM for
program
code
4 I/O Ports
Timer 0
Serial
PortOSC
Interrupt
Control
External interrupts
Timer 1
Timer/Counter
Bus
Control
TxD RxDP0 P1 P2 P3
Address/Data
Counter
Inputs
Fig.3: Internal Structure of Microcontroller
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8. FEATURES OF AT89S51/52
 Compatible with MCS®-51 ProductS
 8K Bytes of In-System Programmable (ISP) Flash Memory
 Endurance: 10,000 Write/Erase Cycles
 4.0V to 5.5V Operating Range
 Fully Static Operation: 0 Hz to 33 MHz
 256 x 8-bit Internal RAM
 32 Programmable I/O Lines
 Three 16-bit Timer/Counters
 Eight Interrupt Sources
 Full Duplex UART Serial Channel
 Interrupt Recovery from Power-down Mode
 Watchdog Timer
 Dual Data Pointer
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9. PIN DESCRIPTION
Fig. 4 :Pin Diagram of Microcontroller
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10. RELAY
IT IS A ELECTRO MAGNETIC SWITCH.
USED TO CONTROL THE ELECTRICAL DEVICES.
COPPER CORE MAGNETIC FLUX PLAYS MAIN ROLE HERE.
Fig. 5 :Relay 6V DC 10

11. The relay's switch connections are usually labeled COM, NC and NO:
COM = Common, always connect to this; it is the moving part of the itch.
NC = Normally Closed, COM is connected to this when the relay coil is off.
NO = Normally Open, COM is connected to this when the relay coil is on
Fig. 6 : Relay's switch connections
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12. RELAY DRIVER (ULN 2003)
ULN2003 is a high voltage and high current Darlington
transistor array.
It consists of seven NPN Darlington pairs that feature high-
voltage outputs with common-cathode Clamp diode for
switching inductive loads.
The ULN2003 has a 2.7kW series base resistor for each
Darlington pair for operation directly with TTL or 5V CMOS
devices.
Current, Output Max:500mA.
Voltage, Input Max:5V.
Voltage, Output Max:50V.
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13. KEYPAD
 A keypad is a set of buttons arranged in a block or
"pad" which usually bear digits, symbols and
usually a complete set of alphabetical letters. If it
mostly contains numbers then it can also be
called a numeric keypad.
 In order to detect which key is pressed from the
matrix, the row lines are to be made low one by
one and read the columns. Assume that if Row1
is made low, then read the columns.
Fig.7:Keypad
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14. DS1307 RTC
RTC?
The RTC chip is a specialized chip that just keeps track of time.
It runs on a battery and keeps time for you even when there is a power
outage!
 Using an RTC, you can keep track of long timelines, even if you
reprogram your microcontroller or disconnect it from USB or a power
plug.
The RTC we'll be using is the DS1307 . It's low cost, easy to solder, and
can run for years on a very small coin cell.
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15.  FEATURES OF DS1307
Real time clock counts seconds, minutes, hours, date of month, month, day of week
and year with leap year compensation valid up to 2100
56 byte nonvolatile RAM for general data storage
2-wrire interface (I2C)
Automatic power fail detect
Consumes less than 500 nA for battery back-up at 25'C
Fig. 8 : Pin Diagram of RTC DS1307
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16. LIQUID CRYSTAL DISPLAY (LCD)
Most common LCDs connected to the microcontrollers are 16x2 and
20x2 displays.
This means 16 characters per line by 2 lines and 20 characters per
line by 2 lines, respectively.
The standard is referred to as HD44780U, which refers to the
controller chip which receives data from an external source (and
communicates directly with the LCD.
Fig. 11 : LCD display
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17. WORKING OF PROJECT
The project uses one real time clock IC DS1307 i.e., Interface to the
MC pin 27 & 28. IT uses a crystal of 32.768 KHz to deliver timing
reference.
A matrix keypad is used for setting the time, relay ON time & OFF
time.
The relay is driven by pin 25 of MC through driving transistor BC547.
Seven segment LED’s are parallel connected to Port 0 through driving
transistors four numbers BL547 to the respective, anode seven segment
LED display as the operation of which is explained before.
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18. SOFTWARE REQUIREMENTS
 Keil an ARM Company makes C compilers, macro assemblers, real-time kernels, debuggers,
simulators, integrated environments, evaluation boards, and emulators for
ARM7/ARM9/Cortex-M3, XC16x/C16x/ST10, 251, and 8051 MCU families.
 Compilers are programs used to convert a High Level Language to object code. Desktop
compilers produce an output object code for the underlying microprocessor, but not for other
microprocessors. i.e the programs written in one of the HLL like ‘C’ will compile the code to
run on the system for a particular processor like x86 (underlying microprocessor in the
computer).
For example compilers for Dos platform is different from the Compilers for Unix
platform So if one wants to define a compiler then compiler is a program that translates
source code into object code. 18

19. FUTURE SCOPE
Further the project can be enhanced by interfacing a GSM modem to the
existing project so that the complete control of the load can be done by
sending an SMS to the control unit.
ADVANTAGES
○ They have low losses
○ They require little maintenance
○ They can work under ordinary atmospheric conditions.
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20. CONCLUSION
The aim of this project is to present the load shedding
phenomena and highlights their use in industry, mobile tower
applications. It has been underlined that this hardware solution
can perfectly address the current challenges in these fields
such as high control performance, reliability and efficiency.
Programmable parameters allow the complete control over the
whole system.
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21. REFERENCE
[1] V.K.Mehta and Rohit Mehta, “Principles of Power System”, 4th ed, S. Chand publication, 2008.
[2] Ashfaq Husain, “Electrical Power System”, 5th ed, CBS Publishers and Distributors Pvt. Ltd.,
2007.
[3] M.A.O liveira and C.C. Barioni, “Technical loss calculation by distribution system segment with
corrections from measurements”, Proc.20th international Conference and Exhibition on Electricity
Distribution, Prague, Czech Republic, June 2009, pp. 1–4.
[4] Sunil S. Rao, “Switchgear Protection and Power Systems”, 9th ed, Khanna Publishers, 2012.
[5] C.L.Wadhwa, “Electrical Power Systems”, 4th ed, New Age International Publishers, 2005.
[6] C. J. Bandim, E. R. Alves ., A. V. Pinto, F. C. Souza, M. R. B. Loureiro, C. A. Magalhges and F.
Galvez-Durand, “Identification of Energy Theft band Tampered Meters Using a Central Observer
Meter: A Mathematical Approach”, Transmission and distribution conference and exposition, 2003
IEEE PES, vol. 1, pp. 163-168,2003.
[7] “RWS-434N Datasheet”, Wenshing electronics co., Ltd., Taipei, Taiwan.
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22. THANK YOU
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