Automatic Power Factor Controller.docx

SRI VENKATESHWARA INSTITUTE OF ENGINEERING NH – 7, BANGALORE MAIN ROAD, MELUMALAI, KRISHNAGIRI-635 115 (ANNA UNIVERSITY, CHENNAI)

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

NAME

: KAVI KUMAR.P.S.

REGISTER NO

: 612516105004

DEGREE / BRANCH

: BE / EEE

SEMESTER

: 6th

SUBJECT

: Presentation skills and Technical seminar.

SUBJECT CODE

: EE-6613

SRI VENKATESHWARA INSTITUTE OF ENGINEERING NH – 7, BANGALORE MAIN ROAD, MELUMALAI, KRISHNAGIRI-635 115

BONAFIDE CERTIFICATE This is to certify that the bonafide record of work done by KAVI KUMAR.P.S. Register number 612516105004 of SIXTH Semester Department ELECTRICAL AND ELECTRONICS ENGINERING

of

in the EE-6613

PRSENTATION SKILLS AND TECHINICAL SEMI AR Laboratory.

LAB - IN-CHARGE

HEAD OF THE DEPARTMENT

Submitted for the practical examination held on …………………….

INTERNAL EXAMINER

EXTERNAL EXAMINER

AUTOMATIC POWER FACTOR CORRECTION

INDEX Particulars

Pg.no

1. INTRODUCTION

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2. LITRATURE SURVEY

3

2.1 POWER FACTOR CORRECTION

4

3. DESIGN AND DEVOLOPMENT 3.1 BLOCK DIAGRAM

5

3.2 CIRCUIT DIAGRAM

6

3.3 CIRCUIT DESCRIPTION

6

3.4 COMPONENTS AND THEIR DESCRIPTION

9

3.5 COST ANALYSIS

18

4. RESTLT ANALYSIS 4.1 RESULT

19

4.2 WORKING MODEL

20

4.3 PROTEUS SIMULATION

21

5. FUTURE SCOPE 5.1 ADVERSE EFFECT OF CORRECTION

22

5.2 ADVANTAGES OF CORRECTED POWER FACTOR

22

6. CONCLUSION

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1.INTRODUCTION

In the present technological revolution, power is very precious and the power system is becoming more and more complex with each passing day. As such it becomes necessary to transmit each unit of power generated over increasing distances with minimum loss of power. However, with increasing number of inductive loads, large variation in load etc. the losses have also increased manifold. Hence, it has become prudent to find out the causes of power loss and improve the power system. Due to increasing use of inductive loads, the load power factor decreases considerably which increases the losses in the system and hence power system losses its efficiency.

Power factor is defined as the ratio of real power to apparent power. This definition is often mathematically represented as KW/KVA, where the numerator is the active (real) power and the denominator is the (active + reactive) or apparent power. It is a measure of how effectively the current is being converted into useful work output. A load with a power factor of 1.0 result in the most efficient loading of the supply and a load with a power factor of 0.5 will result in much higher losses in the supply system. A poor power factor can be the result of either a significant phase difference between the voltage and current at the load terminals, or it can be due to a high harmonic content or distorted/discontinuous current waveform. Poor load current phase angle is generally the result of an inductive load such as an induction motor, power transformer, lighting ballasts, welder or induction furnace. A distorted current waveform can be the result of a rectifier, variable speed drive, switched mode power supply, discharge lighting or other electronic load.

Automatic power factor correction techniques can be applied to industrial units, power systems and also households to make them stable. As a result, the system becomes stable and efficiency of the system as well as of the apparatus in the

1

increases. Therefore, the use of microcontroller based power factor corrector results in reduced overall costs for both the consumers and the suppliers of electrical energy.

Power factor correction using capacitor banks reduces reactive power consumption which will lead to minimization of losses and at the same time increases the electrical system ‘s efficiency. Power saving issues and reactive power management has led to the development of single phase capacitor banks for domestic and industrial applications. The development of this project is to enhance and upgrade the operation of single phase capacitor banks by developing a microprocessor based control system. The control unit will be able to control capacitor bank operating steps based on the varying load current. Current transformer is used to measure the load current for sampling purposes. Intelligent control using this microprocessor control unit ensures even utilization of capacitor steps, minimizes number of switching operations and optimizes power factor correction.

2

2.LITERATURE SURVEY

Pavg = VIcosφ Where, φ is the phase angle between the voltage and current. The term cosφ is called the 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.

Apparent

Reactive

Power

Power

Active Power Fig 2.1: Power Triangle

A load with a power factor of 1.0 result in the most efficient loading of the supply and a load with a power factor of 0.5 will result in much higher losses in the supply system. A poor power factor can be the result of either a significant phase difference between the voltage and current at the load terminals or it can be due to a high harmonic content or distorted/discontinuous current waveform. Poor load current phase angle is generally the result of an inductive load such as an induction motor, power transformer, lighting ballasts, welder or induction furnace. A distorted current waveform can be the result of a rectifier, variable speed drive, switched mode power supply, discharge lighting or other electronic load.

3

2.1. Power Factor Correction Capacitive Power Factor correction is applied to circuits which include induction motors as a means of reducing the inductive component of the current and thereby reduce the losses in the supply. There should be no effect on the operation of the motor itself. An induction motor draws current from the supply that is made up of resistive components and inductive components. 





 The resistive components are: i.

Load current

ii.

Loss current

 The inductive components are i.

Leakage reactance

ii.

Magnetizing current MOTOR CURRENT MAGNETIZING CURRENT

WORK CURRENT Fig 2.2: Current Triangle The current due to the leakage reactance is dependent on the total current drawn by the motor but the magnetizing current is independent of the load on the motor. The magnetizing current will typically be between 20% and 60% of the rated full load current of the motor. The magnetizing current is the current that establishes the flux in the iron and is very necessary if the motor is going to operate. The magnetizing current does not actually contribute to the actual work output of the motor. It is the catalyst that allows the motor to work properly. The magnetizing current and the leakage reactance can be considered passenger components of current that will not affect the power drawn by the motor, but will contribute to the power dissipated in the supply and distribution system.

4

3.DESIGN AND DEVELOPMENT

3.1BLOCK DIAGRAM

Fig:3.1 Block Diagram of Automatic Power Factor Correction Circuit

The above given circuit for Automatic Power Factor detection and correction operates on the principal of constantly monitoring the power factor of the system and to initiate the required correction in case the power factor is less than the set value of power factor

5

3.2 CIRCUIT DIAGRAM

Fig:3.2 Circuit Diagram of APFC

3.3 CIRCUIT DESCRIPTION The voltage signal obtained is converted into the digital by comparator circuit since micro controller accepts the digitized format only. This is given to the microcontroller as one input. Similarly, for current signal, from the current transformer is converted into voltage signal by rectification. As previously digitized the voltage signal, this current signal in the form of voltage is also digitized by the comparator circuit.

6

These two digitized signals i.e. voltage and currents are sent to the microcontroller as the inputs. According to the program written microcontroller calculates the time difference between the zero crossings of these two signals. This time difference is indirectly proportional to the system power factor. The information about this power factor and the power loss is displayed on the LCD display. And according to the range calculated by the microcontroller program; this drives the relays which switches the shunt capacitors across the load. While increasing of the inductive load by connecting the other loads like motors to this circuit results in reduced power factor. This will make the microcontroller to drive the more number of relays resulting in more shunt capacitors to be connected.

In this project simple method of capacitor requirement calculation used based on the time delay between the voltage and current to bring the power factor near to unity. But in real time applications it will not be so. It requires the calculations like load current magnitude and KVAR requirement etc. Number of capacitors requirements depends on the load on the particular system. These parameters must be considered while dealing with the commercial power factor improvement or compensating products.

3.3.1 Zero crossing detector A zero crossing is a point where the sign of a mathematical function changes (e.g. from positive to negative), represented by the crossing of the axis (zero value) in the graph of the function. It is a commonly used term in electronics, mathematics, sound and image processing. In alternating current, the zero-crossing is the instantaneous point at which there is no voltage present. Ina a sine wave this condition normally occurs twice in a cycle. A zero crossing detector is an important application of op-amp comparator circuit. It can also be referred to as a sine to square wave converter. Anyone of the inverting or the non-inverting comparators can be used as a zero crossing detector. The reference voltage in this case is set to zero. The output voltage waveform shows when and in that 7

what direction an input signal crosses zero volts. If input voltage is a low frequency signal, then output voltage will be less quick to switch from one saturation point to another. And if there is noise in between the two input nodes, the output may fluctuate between positive and negative saturation voltage ‗Vsat‘. .Here IC LM358 is used as a zero crossing detector.

Fig:3.3 Zero Crossing Detector 3.3.2 Design of capacitor Motor input = P, Original P.F = Cosθ1, Final P.F = Cosθ2 Required Capacitor kVAR = P (Tan θ1 – Tan θ2) We know that; IC = V/ XC Whereas XC = 1 / 2 π F C IC = V / (1 / 2 π F C) IC = V 2 F C And, kVAR = (V x IC) / 1000 … [kVAR = (V x I)/ 1000] We have already calculated the required Capacity of Capacitor in kVAR, so we can easily convert it into Farads by using this simple formula Required Capacity of Capacitor in Farads/Microfarads 2

C = kVAR / (2 π f V ) in microfarad

8

3.4 COMPONENTS AND THEIR DESCRIPTION 3.4.1 Potential Transformer A potential transformer, a voltage transformer or a laminated core transformer is the most common type of transformer widely used in electrical power transmission and appliances to convert mains voltage to low voltage in order to power low power electronic devices. They are available in power ratings ranging from mW to MW. The Insulated laminations minimize eddy current losses in the iron core. A potential transformer is typically described by its voltage ratio from primary to secondary. A 600:120 potential transformer would provide an output voltage of 120V when a voltage of 600V is impressed across the primary winding. The potential transformer here has a voltage ratio of 230:24 i.e., when the input voltage is the single phase voltage 230V, the output is 24V.

Fig:3.4.1 Potential transformer used as an Instrument Transformer

The potential transformer here is being used for voltage sensing in the line. They are designed to present negligible load to the supply being measured and have an accurate voltage ratio and phase relationship to enable accurate secondary connected metering. The potential transformer is used to supply a voltage of about 12V to the Zero Crossing Detectors for zero crossing detection. The outputs of the potential

9

transformer are taken from one of the peripheral terminals and the central terminal as only a voltage of about 12V is sufficient for the operation of Zero crossing detector circuit. 3.4.2 Current Transformer: The current transformer is an instrument transformer used to step-down the current in the circuit to measurable values and is thus used for measuring alternating currents. When the current in a circuit is too high to apply directly to a measuring instrument, a current transformer produces a reduced current accurately proportional to the current in the circuit, which can in turn be conveniently connected to measuring and recording instruments. A current Transformer isolates the measuring instrument from what may be a very high voltage in the monitored circuit. Current transformers are commonly used in metering and protective relays.

Fig:3.4.2 Current Transformer Like any other transformer, a current transformer has a single turn wire of a very large cross-section as its primary winding and the secondary winding has a large number of turns, thereby reducing the current in the secondary to a fraction of that in the primary. Thus, it has a primary winding, a magnetic core and a secondary winding. The alternating current in the primary produces an alternating magnetic field in the magnetic core, which then induces an alternating current in the secondary winding circuit.

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3.4.3 Capacitor Bank Capacitor banks may also be used in direct current power supplies to increase stored energy and improve the ripple current capacity of the power supply. The capacitor bank consists of a group of four ac capacitors, all rated at 400V, 50 Hz i.e., the supply voltage and frequency. The value of capacitors is different and it consists of four capacitors of 2.5farad. All the capacitors are connected in parallel to one another and the load. The capacitor bank is controlled by the relay module and is connected across the line. The operation of a relay connects the associated capacitor across the line in parallel with the load and other capacitors.

Fig:3.4.3 Capacitor Bank

3.4.4 LM358 The abbreviation LM358 indicates an integrated circuit to 8 feet, containing two operational amplifiers at low power. The LM358 is designed for general use as amplifiers, high-pass filters and low, band pass filters and analogue adders. One of the particularities of this integrated is to be designed to be able to operate with a single static power that ranges from a minimum of 3 V to a maximum of 32 V although typically there settles at levels between 5 V and 15 V. In fact , while as most as like that

11

the integrated circuits containing the operational needs two power supplies, a positive and a negative, the LM358 can be connected to one positive supply while the negative supply is replaced by the mass . However, depending on the needs, it can also introduce the negative power supply by connecting the leg called ground to the appropriate generator. In feeding regime double the voltage range is ± 1.5 ÷ 16 V.

Fig:3.4.4 LM358 Op-amp

3.4.5 Summer/Adder (X-OR) gate: They provide the system designer with a means for implementation of the EXCLUSIVE OR function. Logic gates utilize silicon gate CMOS technology to achieve operating speeds similar to LSTTL gates with the low power consumption of standard CMOS integrated circuits. All devices have the ability to drive STTL loads. The HCT logic family is functionally pin compatible with the standard LS logic family.

12

Fig:3.4.5 X-OR gate 3.4.6 Relay Driver: The ULN2003A are high voltage, high current Darlington arrays each containing seven open collector Darlington pairs with common emitters. Each channel rated at 500mA and can withstand peak currents of 600mA. Suppression diodes are included for inductive load driving and the inputs are pinned opposite the outputs to simplify board layout. The four versions interface to all common logic families:

Fig:3.4.6 ULN 2003A

These versatile devices are useful for driving a wide range of loads including solenoids, relays, DC motors, LED displays filament lamps, thermal print heads and high power buffers. The ULN2001A/2002A/2003A and 2004A are supplied in 16 pin plastic DIP

13

packages with a copper lead frame to reduce thermal resistance. They are available also in small outline package (SO-16) as ULN2001D/2002D/2003D/2004D

Fig:3.4.6 Pinout of uln2003a 3.4.7 RELAY

The relays used in the control circuit are high-quality Single Pole-Double Throw (SPDT), sealed 6V Sugar Cube Relays. These relays operate by virtue of an electromagnetic field generated in a solenoid as current is made to flow in its winding. The control circuit of the relay is usually low power (here, a 6V supply is used) and the controlled circuit is a power circuit with voltage around 230V ac. The relays are individually driven by the relay driver through a 6V power supply. Initially the relay contacts are in the Normally Open ‘state. When a relay operates, the electromagnetic field forces the solenoid to move up and thus the contacts of the external power circuit are made. As the contact is made, the associated capacitor is connected in parallel with the load and across the line. The relay coil is rated up to 8V,

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with a minimum switching voltage of 5V. The contacts of the relay are rated up to 7A @ 270C AC and 7A @ 24V DC.

Fig:3.4.7 relay 3.4.8 LCD (Liquid Crystal Display) LCD panel consist of two patterned glass panels in which crystal is filled under vacuum. The thickness of glass varies according to end use. Most of the LCD modules have glass thickness in the range of 0.70 to 1.1mm. Normally these liquid crystal molecules are placed between glass plates to form a spiral stair case to twist the light. These LCD cannot display any information directly. These act as an interface between electronics and electronics circuit to give a visual output. The values are displayed in the 2x16 LCD modules after converting suitably. The liquid crystal display (LCD), as the name suggests is a technology based on the use of liquid crystal. It is a transparent material but after applying voltage it becomes opaque. This property is the fundamental operating principle of LCDs.

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Fig:3.4.8 Liquid Crystal Display

3.4.9 Arduino Uno

Fig:3.4.9 Arduino Uno The Arduino Uno is a microcontroller board based on the ATmega328. It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic resonator, a USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started.

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The Uno differs from all preceding boards in that it does not use the FTDI USB-toserial driver chip. Instead, it features the Atmega16U2 (Atmega8U2 up to version R2) programmed as a USB-to-serial converter. The Arduino Uno can be powered via the USB connection or with an external power supply. The power source is selected automatically. External (non-USB) power can come either from an AC-to-DC adapter (wall-wart) or battery. Microcontroller

ATmega328

Operating Voltage

5V

Input Voltage (recommended)

7-12V

Input Voltage (limits)

6-20V

Digital I/O Pins

14 (of which 6 provide PWM output)

Analog Input Pins

6

DC Current per I/O Pin

40 mA

DC Current for 3.3V Pin

50 mA

Flash Memory

32 KB (ATmega328) of which 0.5 KB used by bootloader

SRAM

2 KB (ATmega328)

EEPROM

1 KB (ATmega328)

Clock Speed

16 MHz

The Arduino Uno can be programmed with the Arduino software (download). Select "Arduino Uno from the Tools > Board menu (according to the microcontroller on your board). For details, see the reference and tutorials. The ATmega328 on the Arduino Uno comes pre burned with a bootloader that allows you to upload new code to it without the use of an external hardware programmer. It communicates using the original STK500 protocol (reference, C header files).You can also bypass the bootloader and program the microcontroller through the ICSP (In-Circuit Serial Programming) header; see these instructions for details. 17

3.5 COST ANALYSIS

COMPONENTS

SPECIFICATION

QUANTITY

AMOUNT

ARDUINO UNO

1

300

74LS86 XOR

1

8

ULN2003A

1

10

LM358

1

30

LCD

2*16

1

120

CAPACITOR

2.5uf

4

20

RESISTOR

4.7K

4

1

CAPACITOR

.1uf

3

3

240/9V

1

55

7805,7812

2

10

CERAMIC

CERAMIC TRANSFORMER PT REGULATOR

RELAY

6V ,240V 5A

4

15

TRANSFORMER

5A

1

35

CT DIODE

IN4007

4

2

Table 3.1 Cost Analysis

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4.RESULT ANALYSIS 4.1 RESULT The expected outcome of this project is to measuring the power factor value displaying it in the LCD and to improve power factor using capacitor bank and reduce current draw by the load using microcontroller and proper algorithm to turn on capacitor automatically, determine and trigger sufficient switching of capacitor in order to compensate excessive reactive components, thus bringing power factor near to unity ,there by improving the efficiency of the system and reducing the electricity bill. To verify the performance of the automatic power factor correction using microcontroller a prototype is developed and tested. Figure shows the system setup for the automatic power correction using microcontroller. The power supply is of 126V using step down transformer. And it contains a microcontroller, LCD module which is displaying correct power factor and relays which help to include capacitor banks to the circuit as per the necessity. Prototype is verified using, an inductive load. Which initially gives a lagging power factor, which by than gives an improved power factor close to unity by the proper working of the APFC unit.

Fig:4.1

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4.2 WORKING MODEL

Fig:4.2 Project Model

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4.3 PROTEUS SIMULATION

Fig:4.3.1 ZCD Simulation in Multisim Software

Fig:4.3.2 ZCD outputs of current and voltage as inputs to the X-OR

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5.FUTURE SCOPE The automotive power factor correction using capacitive load banks is very efficient as it reduces the cost by decreasing the power drawn from the supply. As it operates automatically, manpower is not required and this Automated Power Factor Correction using capacitive load banks can be used for the industries purpose in the future

5.1 ADVERSE EFFECT OF OVER CORRECTION 1. Power system becomes unstable 2. Resonant frequency is below the line frequency 3. Current and voltage increases

1. 2. 3. 4. 5. 6. 7.

5.2 ADVANTAGES OF CORRECTED 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

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6.CONCLUSION

The Automatic Power Factor Detection and Correction provides 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. However, this system makes use of 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. It can be concluded that power factor correction techniques can be applied to the industries, power systems and also households 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.

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REFERENCE 

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 311-317 

J.G. Cho, J.W. Won, H.S. Lee, ―Reduced conduction loss zero-voltage-transition power factor correction converter with low cost, IEEE Trans. Industrial Electron.

 

vol.45, no 3, Jun. 2000, pp395-400 



V.K Mehta and Rohit Mehta, ―Principles of power system‖, S. Chand & Company Ltd, International Journal of Engineering and Innovative Technology (IJEIT) Volume

3, Issue 4, October 2013 272 Power Factor Correction Using PIC Microcontroller

 

www.arduino.cc Design and Implementation of Microcontroller-Based Controlling of Power Factor Using Capacitor Banks with Load Monitoring, Global Journal of Researches in Engineering Electrical and Electronics Engineering, Volume 13, Issue 2, Version 1.0 Year 2013 Type: Double Blind Peer Reviewed International Research Journal Publisher: Global Journals Inc. (USA) Online ISSN: 2249-4596



& Print ISSN: 0975-5861 

Electric power industry reconstructing in India, Present scenario and future prospects, S.N. Singh, senior member, IEEE and S.C. Srivastava, Senior Member, IEEE.

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ANNEXURES

25 DEPARTMENT OF ELECTRICAL AND ELECTRONICS, SCET

PROJECT’17

Automatic Power Factor Correction

ANNEXURE 1 (ARDUINO PROGRAMMING)

PROGRAM Introduced in 2005, at the Interaction Design Institute Ivrea, in Ivrea, Italy, it was designed to give students an inexpensive and easy way to program interactive objects. It comes with a simple Integrated Development Environment (IDE) that runs on regular personal computers and allows writing programs for Arduino using a combination of simple Java and C or C++

int x,y,r=0; float z;//time,angle,pf,radians,pf2 relay #define echoPin 11 // Echo Pin #define pf1 9 #define pf2 8 #include LiquidCrystal lcd(3, 4, 5, 6, 7, 8);//LCD RS-12,En-11,D4-5,D5- 4,D63,D7-2, void setup() { relayinit(); usinit(); lcdstart(); digitalWrite(pf1,LOW); } void loop() { uscheck(); } void usinit(void) {

26 DEPARTMENT OF ELECTRICAL AND ELECTRONICS, SCET

PROJECT’17

Automatic Power Factor Correction

pinMode(echoPin, INPUT); } void uscheck(void) { x = pulseIn(echoPin,LOW);//reads duartion pulse in Microseconds y = (x*9)/1000; z=cos(y*.01745); if(y>10 && r==0){digitalWrite(pf1,LOW);r=1;} else if (r==1 && y>10){digitalWrite(pf1,LOW); r=0;} if(x>500) { delay(500); lcd.setCursor(0, 0); lcd.print("THE BEST PROJECT"); lcd.setCursor(0, 1); lcd.print("POWERFACTOR="); lcd.print(z); } } void relayinit(void) { pinMode(pf1,OUTPUT); pinMode(pf2,OUTPUT); // pinMode(overvoltrelay,OUTPUT); } void lcdstart(void) { lcd.begin(16, 2);// set up the LCD's number of columns and rows: lcd.clear(); } 27 DEPARTMENT OF ELECTRICAL AND ELECTRONICS, SCET

PROJECT’17

Automatic Power Factor Correction

ANNEXURE 2

PCB DESIGN We are here using the software "gEDA" for designing the PCB. gEDA is a powerful package for designing single-sided and double sided PCBs. It provides a comprehensive range of tools including schematic drawing, schematic capture, component placement, automatic routing, Bill of Materials reporting and file generation for manufacturing

RELAY MODULE PCB DESIGN

ZERO CROSSING DETECTOR 28 DEPARTMENT OF ELECTRICAL AND ELECTRONICS, SCET

PROJECT’17

Automatic Power Factor Correction

ANNEXURE 3 (ATmega 328P)

29 DEPARTMENT OF ELECTRICAL AND ELECTRONICS, SCET

PROJECT’17

Automatic Power Factor Correction

30 DEPARTMENT OF ELECTRICAL AND ELECTRONICS, SCET

PROJECT’17

Automatic Power Factor Correction

31 DEPARTMENT OF ELECTRICAL AND ELECTRONICS, SCET

PROJECT’17

Automatic Power Factor Correction

ANNEXURE 4 (LM 358)

32 DEPARTMENT OF ELECTRICAL AND ELECTRONICS, SCET

PROJECT’17

Automatic Power Factor Correction

33 DEPARTMENT OF ELECTRICAL AND ELECTRONICS, SCET

PROJECT’17

Automatic Power Factor Correction

ANNEXURE 4 (ULN 2003A)

34 DEPARTMENT OF ELECTRICAL AND ELECTRONICS, SCET

PROJECT’17

Automatic Power Factor Correction

35 DEPARTMENT OF ELECTRICAL AND ELECTRONICS, SCET