This project presentation discusses the design of an automatic power factor correction system. The system uses a microcontroller to measure the power factor and control relays that switch capacitor banks in and out of the circuit to maintain a set power factor. When the measured power factor deviates from the set point, the microcontroller activates a relay connecting additional capacitors in parallel to improve the power factor. The system provides an economical way to automatically correct power factor using static capacitors.

1. PROJECT PRESENTATION ON
AUTOMATIC POWER FACTOR
CORRECTION
GUIDED BY:-
LOPAMUDRA SAHU
Presented By:-
Pappu Kumar Dubey (1201214199)
Vikas Kumar Manjhi (1201214203)
Saurav Kumar (1201214205)
Raushan Kumar (1201214218)
Swayam Bikash Samal (1201214219)
Ashish Ranjan Mahto (1201214457)
DEPARTMENT OF ELECTRICAL ENGINEERING
KIST
BHUBANESWAR

2. CONTENTS:
 Introduction
 Block diagram
 Working principle
 Power supply circuit
 Power factor measurement circuit
 Micro Controller
 LCD
 Relay
 Capacitor Bank
 Advantage
 Disadvantage
 Applications
 Conclusion

3. INTRODUCTION:
 This project report represents one of the most effective automatic power factor
improvements.
 Static capacitors which will be controlled by a Microcontroller with very low
cost.
 Power factor is set as standard value into the microcontroller IC.
 Resistors are used instead of potential transformer.
 Microcontroller IC (AT89s52) reduce programming complexity that make it one of
the most economical system than any other controlling system.

4. Source
230V AC
POWER
FACTOR
MEASURMENT
CIRCUIT
LCD Display
Micro controller
RelayCapacitor BankLOAD
Power Supply
230V AC - 5V DC
communication
BLOCK DIAGRAM

5. Working Principle:
 Power supply is given to the circuit.
 Power factor is set as standard value into the microcontroller IC.
 In case of deviations , microcontroller activates relay.
 Relay senses and connects the capacitor.
 The capacitor is connected parallel across the load by relay without any
hazard.
 The APFC unit controls PF by activating/deactivating capacitors.

6. Power Supply Circuit
 Step-down Transformer
 Diode Rectifier
 Filtering Capacitor
 Voltage Regulator

7. POWER FACTOR MEARSURMENT CIRCUIT
Potential
Transformer Current Transformer Zero Crossing Detector

8. Circuit Diagram of ZCD

9. MICRO COTROLLER:
 A Microcontroller Contains:
 The processor (The CPU),
 Program memory,
 Memory for input and output(RAM),
 A clock and an I/O control unit.
 Microcontroller it is an electronic
clock driven reprogrammable device
which can take some digital data ,
process the data and gives us to
required output data.

10. Features of the AT89s52
• High-performance, Low-power Atmel® AVR® 8-bit
Microcontroller
• Advanced RISC Architecture
– 131 Powerful Instructions – Most Single-clock Cycle Execution
– 32 x 8 General Purpose Working Registers
– Fully Static Operation
– Up to 16 MIPS Throughput at 16 MHz
– On-chip 2-cycle Multiplier
• High Endurance Non-volatile Memory segments
– 16 Kbytes of In-System Self-programmable Flash program
memory
– 512 Bytes EEPROM
– 1 Kbyte Internal SRAM
– Write/Erase Cycles: 10,000 Flash/100,000 EEPROM
– Data retention: 20 years at 85°C/100 years at 25°C(1)
– Optional Boot Code Section with Independent Lock Bits
In-System Programming by On-chip Boot Program
True Read-While-Write Operation
– Programming Lock for Software Security

11. Program of Microcontroller
#include<AT89x52.h>
#include<lcd.h>
Sbit Voltage=P1^0;
Unsigned int powerfactor;
Void factor();
Void main()
{ r1=1;
Lcdlnit();
While(1)
{ Display(0*80”, power factor”,16);
Display(65000); Delay(65000);
Factor();
Deley(65000);
If((powerfactor<=0.98)
{r1=0;}}}
Void factor()
{Display(0*80”,Factor Val: “,16)
While(Voltage);
While(!Voltage);
Powerfactor=((cosine(voltage)));
hex(0*86,powerfactor);)

12. LCD:
 A liquid crystal display (LCD) is a flat panel display
 It uses the light modulating properties of liquid
crystals (LCs).
 LCDs Applications:
 Computer monitors,
 Television,
 Instrument panels,signage, etc.
 LCDs have replaced cathode ray tube (CRT) displays in
most applications.

13. LCD PINOUT:

14. RELAY:

15. WORKING OF RELAY:
 A relay is an electrically operated switch.
 The coil current can be on or off so relays have two switch
positions and they are double throw (changeover) switches.
 Relays allow one circuit to switch a second circuit which can
be completely separate from the first.
 It is also known as a sensing device.

16. Capacitor Bank
A capacitor bank is a group of several capacitors of the
same rating that are connected in series or parallel with
each other to store electrical energy .
The resulting bank is then used to counteract(resist) or
correct a power factor lag or phase shift in an
alternative current (AC) power supply. They can also be
used in a direct current (DC) power supply to increase
the ripple current capacity of the power supply or to
increase the overall amount of stored energy.
Capacitor banks are generally used in substations. Since
most of the household and industrial appliances are
either resistive(eg. incandescent light, heater, etc.) or
inductive(e.g. refrigerator, air-conditioner, motor, etc).
The capacitive load of the capacitor bank will help to
adjust the power factor as close to 1 as possible, in
which case the voltage and current are in phase and
deliver maximum usable power to the load.

17. Advantage
• 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

18. Disadvantage
 They have short service life ranging from 8 to 10 years
 They are easily damaged if the voltage exceeds the rated value
 Once the capacitor is damaged, their repair is uneconomical.

19. Applications:
 Linear loads with low power factor (such as induction motors).
 A high power factor is generally desirable in a transmission system to reduce
transmission losses and improve voltage.
 Alarm signals for:
 failure to reach the target PF
 overcurrent in the capacitor
 Defects at capacitor stages

20. CONCLUSION :
 This paper shows an efficient technique to improve the power factor of a
power system by an economical way. Static capacitors are invariably used for
power factor improvement in factories or distribution line. But this paper
presents a system that uses capacitors only when power factor is low
otherwise they are cut off from line. Thus it not only improves the power
factor but also increases the life time of static capacitors. The power factor
of any distribution line can also be improved easily by low cost small rating
capacitor. This system with static capacitor can improve the power factor of
any distribution line from load side. As, if this static capacitor will apply in
the high voltage transmission line then it’s rating will be unexpectedly large
which will be uneconomical & inefficient. So a variable speed synchronous
condenser can be used in any high voltage transmission line to improve power
factor & the speed of synchronous condenser can be controlled by
microcontroller or any controlled device.