power factor

1. POWER FACTOR IMPROVEMENT BY
AUTOMATICALLY ENGAGING APPROPRIATE
NUMBER OF SHUNT CAPACITOR FOR
INDUCTIVE LOADS
Under the Guidance of:
Submitted by:
1)SHITOLE SANKET SUBHASH

2. INTRODUCTION
In the present scenario of technological revolution it has
been observed that the power is very precious. The
industrialization is primarily increasing the inductive loading,
the Inductive loads affect the power factor so the power
system losses its efficiency. There are certain organizations
developing products and caring R&D work on this field to
improve or compensate the power factor. The Automatic
Power factor Correction device is a very useful device for
improving efficient transmission of active power. Automatic
Power factor correction device reads the power factor from
line voltage and line current, calculating the compensation
requirement switch on different capacitor banks.

3. WHAT IS POWER FACTOR

Power factor is the ration between the KW and
the KVA drawn by an electrical load where the
KW is the actual load power and the KVA is the
apparent load power. It is a measure of how
effectively the current is being converted into
useful work output and more particularly is a
good indicator of the effect of the load current on
the efficiency of the supply system.

4. Why APFC are required:
In industry most of the load is inductive in
nature which results in lagging power factor
that is why there is loss and wastage of
energy which results in high power bills and
heavy penalties from electricity boards. If the
load is uneven it is very difficult to maintain
unity power factor. To overcome this difficulty
APFC panel is used which maintains unity
P.F.

5. HARDWARE COMPONENTS
MICROCONTROLLER (AT89S52)
RELAY
RELAY DRIVER
LCD
CURRENT TRANSFORMER
INDUCTIVE LOAD
SHUNT CAPACITOR
PUSH BUTTONS
LED
RESISTOR
CAPACITOR

7. POWER SUPPLY
Bridge rectifier
230 V AC
50 Hz
5v Regulator
5V
DC
12V step down
transformer
Filter(470µf)

8. MICROCONTROLLER
 It
is a smaller computer
 Has on-chip RAM, ROM, I/O ports...
CPU
I/O
Port
RAM ROM
Serial
Timer COM
Port
A single chip
Microcontroller

9. INTERNAL STRUCTURE OF A MICRO CONTROLLERAT89S52/51
External interrupts
Interrup
t
Control
On-chip
ROM for
program
code
Timer/Counter
On-chip
RAM
Timer 1
Timer 0
CPU
OSC
Bus
Control
4 I/O Ports
P0 P1 P2 P3
Address/Data
Serial
Port
TxD RxD
Counter
Inputs

10. 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

11. PIN DESCRIPTION

12. RELAY
IT IS A ELECTRO MAGNETIC SWITCH
USED TO CONTROL THE ELECTRICAL DEVICES
COPPER CORE MAGNETIC FLUX PLAYS MAIN ROLE HERE

13. 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

14. RELAY DRIVER (ULN 2003)
ULN2003 is a high voltage and high current Darlington
transistor array
It consists of seven NPN Darlington pairs that feature highvoltage 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

15. Fig: ULN 2003

16. QUAD VOLTAGE COMPARATOR
LM339
● Wide single supply voltage range 2.0VDC TO 36VDC or dual
supplies ±1.0VDC to ±18VDC
● Very low supply current drain (0.8 ㎃ ) independent
of supply voltage (1.0 ㎽ /comparator at 5.0VDC)
● Low input biasing current 25 ㎁
● Low input offset current ±5 ㎁ and offset voltage
● Input common-mode voltage range includes ground
● Differential input voltage range equal to the power
supply voltage
● Low output 250 ㎷ at 4 ㎃ saturation voltage
● Output voltage compatible with TTL, DTL, ECL, MOS
and CMOS logic system
● Moisture Sensitivity Level 3

17. 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.

18. LCD BACKGROUND
If an 8-bit data bus is used the LCD will require 11 data lines
(3 control lines plus the 8 lines for the data bus)
The three control lines are referred to as EN, RS, and RW
EN=Enable (used to tell the LCD that you are sending it data)
RS=Register Select (When RS is low (0), data is treated as a command)
(When RS is High(1), data being sent is text data )
R/W=Read/Write (When RW is low (0), the data written to the LCD)
(When RW is low (0), the data reading to the LCD)

19. SOFTWARE REQUIREMENTS

Keil an ARM Company makes C compilers, macro assemblers, realtime
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.

20. ADVERSE EFFECT OF OVER
CORRECTION

Power system becomes unstable

Resonant frequency is below the line frequency

Current and voltage increases

21. ADVANTAGES OF IMPROVED
POWER FACTOR
Reactive power decreases
 Avoid poor voltage regulation
 Overloading is avoided
 Copper loss decreases
 Transmission loss decreases
 Improved voltage control
 Efficiency of supply system and apparatus
increases


22. CONCLUSION:
It can be concluded that power factor
correction techniques can be applied to the
industries, power systems and also house
holds to make them stable and due to that
the system becomes stable and efficiency of
the system as well as the apparatus
increases. The use of microcontroller
reduces the costs. Due to use of
microcontroller multiple parameters can be
controlled and the use of extra hard wares
such as timer , RAM,ROM and input output
ports reduces.

23. REFERENCES
 P.
N. Enjeti and R martinez, “A high
performance single phase rectifier with
input power factor correction ,”IEEE
Trans. Power
Electron..vol.11,No.2,Mar.2003.pp 311317
 “The 8051 Microcontroller and Embedded
Systems” by Muhammad Ali Mazidi and
Janice Gillispie Mazidi.
 Data sheet of micro controller AT89S52 by
ATMEL CORPORATION

24. ANKYOU
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