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CHAPTER1

INTRODUCTION

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1.1INTRODUCTION

Nowadays, modern industrial devices are mostly based on electronic devices

such as programmable logic controllers and electronic drives. The electronic devices

are very sensitive to disturbances and become less tolerant to power quality problems

such as voltage sags, swells and harmonics. Voltage dips are considered to be one of

the most severe disturbances to the industrial equipments.

Voltage support at a load can be achieved by reactive power injection at the

load point of common coupling. The common method for this is to install

mechanically switched shunt capacitors in the primary terminal of the distribution

transformer. The mechanical switching may be on a schedule, via signals from a

supervisory control and data acquisition (SCADA) system, with some timing

schedule, or with no switching at all. The disadvantage is that, high speed transients

cannot be compensated. Some sags are not corrected within the limited time frame of

mechanical switching devices. Transformer taps may be used, but tap changing under

load is costly.

Another power electronic solution to the voltage regulation is the use of a

dynamic voltage restorer (DVR). DVRs are a class of custom power devices for

providing reliable distribution power quality. They employ a series of voltage boost

technology using solid state switches for compensating voltage sags/swells. The DVR

applications are mainly for sensitive loads that may be drastically affected by

fluctuations in system voltage.

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CHAPTER2

LITERATURE REVIEW

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2.1 SOURCES AND EFFECTS OF POWER QUALITY PROBLEMS

Fig 2.1 Single Line Diagram of Power Supply System

Power distribution systems, ideally, should provide their customers with an

uninterrupted flow of energy at smooth sinusoidal voltage at the contracted magnitude

level and frequency. However, in practice, power systems, especially the distribution

systems, have numerous nonlinear loads, which significantly affect the quality of

power supplies. As a result of the nonlinear loads, the purity of the waveform of

supplies is lost. This ends up producing many power quality problems.

The Consumers

Secondary Distribution

Secondary Transmission

Primar Transmission

Primary Distribution

Medium Scale

Industries

Small Scale

Industries

Step-up Transformer: 11/220 kV

Step-down Transformer: 220/33 kV

Step-down Transformer: 33/11 kV

Step-down Transformer: 11/0.4 kV

G 11 kV

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While power disturbances occur on all electrical systems, the sensitivity of

todays sophisticated electronic devices makes them more susceptible to the quality of

power supply. For some sensitive devices, a momentary disturbance can cause

scrambled data, interrupted communications, a frozen mouse, system crashes and

equipment failure etc. A power voltage spike can damage valuable components. Power

Quality problems encompass a wide range of disturbances such as voltage sags/swells,

flicker, harmonics distortion, impulse transient, and interruptions.

Voltage Dip: A voltage dip is used to refer to short-term reduction in voltage ofless than half a second.

Voltage Sag: Voltage sags can occur at any instant of time, with amplitudesranging from 1090% and a duration lasting for half a cycle to one minute.

Voltage Swell: Voltage swell is defined as an increase in rms voltage or currentat the power frequency for durations from 0.5 cycles to 1 min.

Voltage 'Spikes', 'Impulses' Or 'Surges': These are terms used to describeabrupt, very brief increases in voltage value.

Voltage Transients: They are temporary, undesirable voltages that appear onthe power supply line. Transients are high over-voltage disturbances (up to

20KV) that last for a very short time.

Harmonics: The fundamental frequency of the AC electric power distributionsystem is 50 Hz. A harmonic frequency is any sinusoidal frequency, which is a

multiple of the fundamental frequency. Harmonic frequencies can be even or

odd multiples of the sinusoidal fundamental frequency. Flickers: Visual irritation and introduction of many harmonic components in

the supply power and their associated ill effects.

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2.1.1 Causes Of Dips, Sags And Surges:

1. Rural location remote from power source

2. Unbalanced load on a three phase system

3. Switching of heavy loads

4. Long distance from a distribution transformer with interposed loads

5. Unreliable grid systems

6. Equipments not suitable for local supply

2.1.2 Causes Of Transients And Spikes:

1. Lightening2. Arc welding3. Switching on heavy or reactive equipments such as motors, transformers, motor

drives

4. Electric grade switching2.2 STANDARDS ASSOCIATED WITH VOLTAGE SAGS

Standards associated with voltage sags are intended to be used as reference

documents describing single components and systems in a power system. Both the

manufacturers and the buyers use these standards to meet better power qualityrequirements. Manufactures develop products meeting the requirements of a standard,

and buyers demand from the manufactures that the product comply with the standard.

The most common standards dealing with power quality are the ones issued by

IEEE, IEC, CBEMA, and SEMI.

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2.2.1 IEEE Standard

The Technical Committees of the IEEE societies and the Standards

Coordinating Committees of IEEE Standards Board develop IEEE standards. The

IEEE standards associated with voltage sags are given below.

IEEE 446-1995, IEEE recommended practice for emergency and standby

power systems for industrial and commercial applications range of sensibility loads

The standard discusses the effect of voltage sags on sensitive equipment, motor

starting, etc. It shows principles and examples on how systems shall be designed to

avoid voltage sags and other power quality problems when backup system operates.

IEEE 493-1990, Recommended practice for the design of reliable industrial and

commercialpower systems

The standard proposes different techniques to predict voltage sagcharacteristics, magnitude duration and frequency. There are mainly three areas of

interest for voltage sags.

The different areas can be summarized as follows:

Calculating voltage sag magnitude by calculating voltage drop at critical loadwith knowledge of the network impedance, fault impedance and location of

fault.

By studying protection equipment and fault clearing time it is possible toestimate the duration of the voltage sag.

Based on reliable data for the neighbourhood and knowledge of the systemParameters an estimation of frequency of occurrence can be made.

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IEEE 1100-1999, IEEE recommended practice for powering and grounding

Electronic equipment

This standard presents different monitoring criteria for voltage sags and has a

chapter explaining the basics of voltage sags. It also explains the background and

application of the CBEMA (ITI) curves. It is in some parts very similar to Std. 1159

but not as specific in defining different types of disturbances.

IEEE 1159-1995, IEEE recommended practice for monitoring electric power

quality

The purpose of this standard is to describe how to interpret and monitor

electromagnetic phenomena properly. It provides unique definitions for each type of

disturbance.

IEEE 1250-1995, IEEE guide for service to equipment sensitive to momentaryvoltage disturbances

This standard describes the effect of voltage sags on computers and sensitive

equipment using solid-state power conversion. The primary purpose is to help identify

potential problems. It also aims to suggest methods for voltage sag sensitive devices to

operate safely during disturbances. It tries to categorize the voltage-related problemsthat can be fixed by the utility and those which have to be addressed by the user or

equipment designer. The second goal is to help designers of equipment to better

understand the environment in which their devices will operate. The standard explains

different causes of sags, lists of examples of sensitive loads, and offers solutions to the

problems.

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2.2.2 SEMI International Standards

The SEMI International Standards Program is a service offered by

Semiconductor Equipment and Materials International (SEMI). Its purpose is to

provide the semiconductor and flat panel display industries with standards and

recommendations to improve productivity and business. SEMI standards are written

documents in the form of specifications, guides, test methods, terminology, and

practices. The standards are voluntary technical agreements between equipment

manufacturer and end-user.

The standards ensure compatibility and interoperability of goods and services.

Considering voltage sags, two standards address the problem for the equipment.

SEMI F47-0200, Specification for semiconductor processing equipment

voltage sag immunity. The standard addresses specifications for semiconductor

processing equipment voltage sag immunity. It only specifies voltage sags withduration from 50ms up to 1s. It is also limited to phase-to-phase and phase-to-neutral

voltage incidents, and presents a voltage-duration graph, shown in Figure 2.2. SEMI

F42-0999, Test method for semiconductor processing equipment voltage sag

immunity

This standard defines a test methodology used to determine the susceptibility ofsemiconductor processing equipment and how to qualify it against the specifications.

It further describes test apparatus, test set-up, test procedure to determine the

susceptibility of semiconductor processing equipment, and finally how to report and

interpret the results.

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2.3 SOLUTIONS TO POWER QUALITY PROBLEMS:

There are two approaches to the mitigation of power quality problems. The

solution to the power quality can be done from customer side or from utility side Firstapproach is called load conditioning, which ensures that the equipment is less sensitive

to power disturbances, allowing the operation even under significant voltage

distortion. The other solution is to install line conditioning systems that suppress or

counteracts the power system disturbances. Currently they are based on PWM

converters and connect to low and medium voltage distribution system in shunt or in

series. Series active power filters must operate in conjunction with shunt passive filters

in order to compensate load current harmonics. Shunt active power filters operate as a

controllable current source and series active power filters operates as a controllable

voltage source. Both schemes are implemented preferable with voltage source PWM

inverters, with a dc bus having a reactive element such as a capacitor. However, with

the restructuring of power sector and with shifting trend towards distributed and

dispersed generation, the line conditioning systems or utility side solutions will play a

major role in improving the inherent supply quality; some of the effective and

economic measures can be identified as following:

2.3.1 Lightening and Surge Arresters:

Arresters are designed for lightening protection of transformers, but are not

sufficiently voltage limiting for protecting sensitive electronic control circuits from

voltage surges.

2.3.2 Thyristor Based Static Switches:

The static switch is a versatile device for switching a new element into the

circuit when the voltage support is needed. It has a dynamic response time of about

one cycle. To correct quickly for voltage spikes, sags or interruptions, the static switch

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can used to switch one or more of devices such as capacitor, filter, alternate power

line, energy storage systems etc. The static switch can be used in the alternate power

line applications.

2.3.3 Energy Storage Systems:

Storage systems can be used to protect sensitive production equipments from

shutdowns caused by voltage sags or momentary interruptions. These are usually DC

storage systems such as UPS, batteries, superconducting magnet energy storage

(SMES), storage capacitors or even fly wheels driving DC generators .The output of

these devices can be supplied to the system through an inverter on a momentary basis

by a fast acting electronic switch. Enough energy is fed to the system to compensate

for the energy that would be lost by the voltage sag or interruption.

Though there are many different methods to mitigate voltage sags and swells,

but the use of a custom Power device is considered to be the most efficient method.

For example, Flexible AC Transmission Systems (FACTS) for transmission systems,

the term custom power pertains to the use of power electronics controllers in a

distribution system, specially, to deal with various power quality problems. Just as

FACTS improves the power transfer capabilities and stability margins, custom power

makes sure customers get pre-specified quality and reliability of supply. This pre-

specified quality may contain a combination of specifications of the following: low

phase unbalance, no power interruptions, low flicker at the load voltage, low harmonic

distortion in load voltage, magnitude and duration of overvoltage and under voltages

within specified limits, acceptance of fluctuations, and poor factor loads without

significant effect on the terminal voltage There are many types of Custom Power

devices. Some of these devices include: Active Power Filters (APF), Battery Energy

Storage Systems (BESS), Distribution STATic synchronous COMpensators

(DSTATCOM), Distribution Series Capacitors (DSC), Dynamic Voltage Restorer

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(DVR), Surge Arresters (SA), Super conducting Magnetic Energy Systems (SMES),

Static Electronic Tap Changers (SETC), Solid-State Transfer Switches (SSTS), Solid

State Fault Current Limiter (SSFCL), Static Var Compensator (SVC), Thyristor

Switched Capacitors (TSC), and Uninterruptible Power Supplies (UPS).

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CHAPTER3

DYNAMIC VOLTAGE RESTORER

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3.1 INTRODUCTION

Among the power quality problems (sags, swells, harmonics) voltage sags are

the most severe disturbances. In order to overcome these problems the concept of

custom power devices is introduced recently. One of those devices is the Dynamic

Voltage Restorer (DVR), which is the most efficient and effective modern custom

power device used in power distribution networks. DVR is a recently proposed series

connected solid state device that injects voltage into the system in order to regulate the

load side voltage. It is normally installed in a distribution system between the supply

and the critical load feeder at the point of common coupling (PCC). Other than voltage

sags and swells compensation, DVR can also added other features like: line voltage

harmonics compensation, reduction of transients in voltage and fault current

limitations.

Fig 3.1 Location of DVR

Load 1

Sensitive

loadAC Source Step-down

Transformer

Step-down

Transformer

Step-down

Transformer

DVR

Transmission

lineDistribution

line

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3.2 BASIC CONFIGURATION OF DVR:

The general configuration of the DVR consists of:

i. An Injection/ Booster transformer

ii. A Harmonic filter

iii. Storage Devices

iv. A Voltage Source Converter (VSC)

v. DC charging circuit

vi. A Control and Protection system

Fig 3.2 Schematic Diagram of DVR

Impedance

Supply

VS VL

VDVR Load

Filter

VSCControl

System

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3.2.1 Injection/ Booster transformer:

The Injection / Booster transformer is a specially designed transformer that

attempts to limit the coupling of noise and transient energy from the primary side to

the secondary side. Its main tasks are:

It connects the DVR to the distribution network via the HV-windings andtransforms and couples the injected compensating voltages generated by the

voltage source converters to the incoming supply voltage.

In addition, the Injection / Booster transformer serves the purpose of isolatingthe load from the system (VSC and control mechanism).

3.2.2 Harmonic Filter:

The main task of harmonic filter is to keep the harmonic voltage content

generated by the VSC to the permissible level.

3.2.3 Voltage Source Inverter:

A VSI is a power electronic system consists of a storage device and switching

devices, which can generate a sinusoidal voltage at any required frequency,

magnitude, and phase angle. In the DVR application, the VSC is used to temporarilyreplace the supply voltage or to generate the part of the supply voltage which is

missing.

There are four main types of switching devices: Metal Oxide Semiconductor

Field Effect Transistors (MOSFET), Gate Turn-Off thyristors (GTO), Insulated Gate

Bipolar Transistors (IGBT), and Integrated Gate Commutated Thyristors (IGCT).

Each type has its own benefits and drawbacks. The IGCT is a recent compact device

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with enhanced performance and reliability that allows building VSC with very

large power ratings. Because of the highly sophisticated converter design with IGCTs,

the DVR can compensate dips which are beyond the capability of the past DVRs using

conventional devices.

The purpose of storage devices is to supply the necessary energy to the VSC via

a dc link for the generation of injected voltages. The different kinds of energy storage

devices are Superconductive magnetic energy storage (SMES), batteries and

capacitance.

3.2.4 DC Charging Circuit:

The dc charging circuit has two main tasks.

The first task is to charge the energy source after a sag compensation event. The second task is to maintain dc link voltage at the nominal dc link voltage.

3.2.5 Control And Protection:

The control mechanism of the general configuration typically consists of

hardware with programmable logic. All protective functions of the DVR should beimplemented in the software. Differential current protection of the transformer, or

short circuit current on the customer load side are only two examples of many

protection functions possibility.

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3.3 EQUATIONS RELATED TO DVR

The system impedance Zth depends on the fault level of the load bus. When the

system voltage (Vth) drops, the DVR injects a series voltage VDVR through the injection

transformer so that the desired load voltage magnitude VL can be maintained. The

series injected voltage of the DVR can be written as

VDVR= VL +ZTHIL- VTH (3.1)

Where

VL = The desired load voltage magnitude

ZTH = The load impedance

IL = The load current

VTH = The system voltage during fault condition

The load current IL is given by,

IL=

(3.2)

When VL is considered as a reference equation can be written as,

VDVR

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() (3.4)

The complex power injection of the DVR can be written as,

SDVR = VDVR IL* (3.5)

It requires the injection of only reactive power and the D

VR itself is capable of generating the reactive power.

3.4 OPERATING MODES OF DVR:

The basic function of the DVR is to inject a dynamically controlled voltage

VDVR generated by a forced commutated converter in series to the bus voltage by

means of a booster transformer. The momentary amplitudes of the three injected phase

voltages are controlled such as to eliminate any detrimental effects of a bus fault to the

load voltage VL. This means that any differential voltages caused by transient

disturbances in the ac feeder will be compensated by an equivalent voltage generated

by the converter and injected on the medium voltage level through the booster

transformer. The DVR has three modes of operation which are: protection mode,

standby mode, injection/boost mode.

3.4.1 Protection mode:

If the over current on the load side exceeds a permissible limit due to short

circuit on the load or large inrush current, the DVR will be isolated from the systems

by using the bypass switches (S2 and S3 will open) and supplying another path for

current (S1 will be closed).

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3.4.2 Standby Mode: (VDVR= 0)

In the standby mode the booster transformers low voltage winding is shorted

through the converter. No switching of semiconductors occurs in this mode of

operation and the full load current will pass through the primary.

3.4.3 Injection/Boost Mode: (VDVR>0)

In the Injection/Boost mode the DVR is injecting a compensating voltage

through the booster transformer due to the detection of a disturbance in the supply

voltage.

Fig 3.4 Protection Mode (Creating another path for current)

Fig 3.5 Standby Mode

Source Sensitive Load

Booster Transformer

Bypass

Switche

s

S1

S2S3

Source Sensitive load

Booster TransformerLV winding

Bypass Converter

Switches

Filter

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3.5 VOLTAGE INJECTION METHODS OF DVR:

Voltage injection or compensation methods by means of a DVR depend upon

the limiting factors such as; DVR power ratings, various conditions of load, and

different types of voltage sags. Some loads are sensitive towards phase angel jump and

some are sensitive towards change in magnitude and others are tolerant to these.

Therefore the control strategies depend upon the

type of load characteristics.

There are four different methods of DVR voltage injection which are

i. Pre-sag compensation method

ii. In-phase compensation method

iii. In-phase advanced compensation method

iv. Voltage tolerance method with minimum energy injection

3.5.1 Pre-Sag/Dip Compensation Method:

The pre-sag method tracks the supply voltage continuously and if it detects any

disturbances in supply voltage it will inject the difference voltage between the sag or

voltage at PCC and pre-fault condition, so that the load voltage can be restored back to

the pre-fault condition. Compensation of voltage sags in the both phase angle and

amplitude sensitive loads would be achieved by pre-sag compensation method. In thismethod the injected active power cannot be controlled and it is determined by external

conditions such as the type of faults and load conditions

VDVR=Vprefault - Vsag (3.6)

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3.5.2 In-Phase Compensation Method:

This is the most straight forward method. In this method the injected voltage is

in phase with the supply side voltage irrespective of the load current and pre-fault

voltage.The phase angles of pre-sag and load voltage are different but the most

important criteria for power quality that is the constant magnitude of load voltage are

satisfied

.

Fig 3.6 Pre Sag Compensation

Fig 3.7 In Phase Compensation Method

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|VL|=|Vprefault| (3.7)

One of the advantages of this method is that the amplitude of DVR injection

voltage is minimum for a certain voltage sag in comparison with other strategies.

Practical application of this method is in non-sensitive loads to phase angle jump.

3.5.3 In-Phase Advanced Compensation Method:

In this method the real power spent by the DVR is decreased by minimizing the

power angle between the sag voltage and load current. In case of pre-sag and in-phase

compensation method the active power is injected into the system during disturbances.

The active power supply is limited stored energy in the DC links and this part is one of

the most expensive parts of DVR. The minimization of injected energy is achieved by

making the active power component zero by having the injection voltage phasor

perpendicular to the load current phasor.

In this method the values of load current and voltage are fixed in the system so

we can change only the phase of the sag voltage. IPAC method uses only reactive

power and unfortunately, not al1 the sags can be mitigated without real power, as a

consequence, this method is only suitable for a limited range of sags.

3.5.4 Voltage Tolerance Method with Minimum Energy Injection:

A small drop in voltage and small jump in phase angle can be tolerated by the

load itself. If the voltage magnitude lies between 90%-110% of nominal voltage and

5%-10% of nominal state that will not disturb the operation characteristics of loads.

Both magnitude and phase are the control parameter for this method which can be

achieved by small energy injection.

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Fig 3.8 Voltage Tolerance Method with Minimum Energy

Injection

Load

Voltage

Tolerance

Pre-sag

Voltage

Vload

Vsag

VDVR

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CHAPTER -4

REALIZATION OF COMPENSATION TECHNIQUE

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4.1 SOFTWARE USED

Software usedMATLAB 7.04.1.1 MATLAB Introduction

MATLAB is a high-level technical computing language and interactive

environment for algorithm development, data visualization, data analysis, and

numerical computation. Using MATLAB, you can solve technical computing

problems faster than with traditional programming languages, such as C, C++, and

FORTRAN. You can use MATLAB in a wide range of applications, including signal

and image processing, communications, control design, test and measurement,

financial modelling and analysis, and computational biology. Add-on toolboxes

(collections of special-purpose MATLAB functions) extend the MATLAB

environment to solve particular classes of problems in these application areas.

MATLAB provides a number of features for documenting and sharing your

work. You can integrate your MATLAB code with other languages and applications,

and distribute your MATLAB algorithms and applications.

4.1.2 SIMULINK Introduction

Simulink is a software package for modelling, simulating, and analyzing

dynamical systems. It supports linear and nonlinear systems, modelled in continuous

time, sampled time, or a hybrid of the two. Systems can also be multirate, i.e., have

different parts that are sampled or updated at different rates.

For modelling, Simulink provides a graphical user interface (GUI) for building

models as block diagrams, using click-and-drag mouse operations. With this interface,

you can draw the models just as you would with pencil and paper (or as most

textbooks depict them). Simulink includes a comprehensive block library of sinks,

sources, linear and nonlinear components, and connectors. You can also customize

and create your own blocks Models are hierarchical. This approach provides insight

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into how a model is organized and how its parts interact. After you define a model,

you can simulate it, using a choice of integration methods, either from the Simulink

menus or by entering commands in MATLAB's command window. The menus are

particularly convenient for interactive work, while the command-line approach is very

useful for running a batch of simulations (for example, if you are doing Monte Carlo

simulations or want to sweep a parameter across a range of values). Using scopes and

other display blocks, you can see the simulation results while the simulation is

running. In addition, you can change parameters and immediately see what happens,

for "what if" exploration. The simulation results can be put in the MATLAB

workspace for post processing and visualization. And because MATLAB and

Simulink are integrated, you can simulate, analyze, and revise your models in either

environment at any point.

4.2 ARTIFICIAL NEURAL NETWORK BASED CONTROL SCHEME

The input-output data necessary for the off-line training of the neural network

have been obtained in the present work using the voltage transfer ratio of the chosen

inverter. The data set is made sufficiently rich to ensure stable operation since no

additional learning will take place after training. A back-propagation algorithm is used

for training of the created network. The LEARNGDM function which has a gradient

descent with momentum weight / bias learning is used in this work.

Learning occurs according to the learning parameters:

Learning rate=0.01 and momentum constant t= 0.9

The neural network weights are:

After load disturbances:

w1= -4.3396

1.0328

-0.9796

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-4.1411

b1= 4.5387

-0.6714

-0.7780

-4.1621

w2= 0.0259 -0.5370 1.0723 0.0682

b2 = 0.2595

After supply disturbances:

w1= 4.2698-1.0492

0.8594

4.1234

b1= -4.3006

0.7756

0.6985

4.0341

w2= -0.0172 0.4589 -1.2668 -0.0568

b2 = 0.3386

MSE is the performance criteria used in this work that evaluates the network

according to the mean of the square of the error between the target and computed

output. The minimum MSE that can be achieved in this work is 1e-7.

For a back-propagation training algorithm, the derivative of the activation

function is needed. Therefore, the activation function selected must be differentiable.

The sigmoid function satisfies this requirement and it is the commonly used soft-

limiting activation function. It is also quite common to use linear output nodes to make

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learning easier and using a linear activation function in the output layer does not

squash (compress) the range of output.

Hence, a bipolar sigmoid activation function and a linear activation function are

used for the hidden and output layers, respectively. Trials have been carried out to

obtain maximum accuracy with a minimum number of neurons per layer. The feed

forward neural network developed consists of one neuron in the input layer, four

neurons in the hidden layer and one neuron in the output layer. The optimum number

of neurons for the hidden layer is chosen as four since the number of epochs for

training the neural network is reduced considerably. The tansig function is found to be

better than the logsig activation function for the hidden layer since the logsig function

takes approximately 200 more epochs than the tansig function. The input to the neuro

controller is voltage error (e). The output of the controller is the corrected duty ratio

(dk)

Fig 4.1 Simulink Model of DVR Controller

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4.3 TEST SYSTEM FOR DVR

Fig 4.2 Single Line Diagram of Test System of DVR

Single line diagram of the test system for DVR is composed by a 13 kV, 50 Hz

generation system, feeding two transmission lines through a 3- winding transformer

connected in Y//, 13/115/115 kV. Such transmission lines feed two distributionnetworks through two transformers connected in /Y,115/11 kV. To verify the

working of DVR for voltage compensation a fault is applied at point X at resistance

0.66 U for time duration of 200 ms. The DVR is simulated to be in operation only for

the duration of the fault.

4.4 PARAMETERS USED IN SIMULINK MODEL OF DVR

3-PHASE SOURCE

Phase To Phase Rms Voltage: 13KV

Frequrency: 50HzSource Resistance: 0.1 Ohms

3-PHASE 3-WINDING

TRANSFORMER

Winding 1: 13KV, Resistance

0.002pu, Inductance 0.08puDelta Connected

Winding 2: 115KV, Resistance0.002pu, Inductance 0.08puDelta ConnectedWinding 3: 115KV, Resistance0.002pu, Inductance 0.08pu

Impedance

Impedance

115/11 kV

115/11 kV 3phase fault Breaker

Load 1

13/115/115 kV

Controller

Vs 13 kV

Load 2

Vs

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3-PHASE RLC SERIES

ELEMENTS

ParametersResistance: 0.05 Ohms

Inductance: 0.4806 HCapacitance: 1e-6 F

3-PHASE RLC SERIES

ELEMENTS

ParametersResistance: 20 OhmsInductance: 0.5 H

Capacitance: 1e-6 F

3-PHASE 2-WINDING

TRANSFORMER

Winding 1: 115KV, Resistance0.002pu, Inductance 0.08pu

Star ConnectedWinding 2: 11KV, Resistance

0.002pu, Inductance 0.08puDelta Connected

3-PHASE 2-WINDING

TRANSFORMER

Winding 1: 115KV, Resistance0.002pu, Inductance 0.08puDelta ConnectedWinding 2: 11KV, Resistance

0.002pu, Inductance 0.08puStar Connected

LOADS CONNECTED

1) 3-PHASE RLC SERIESELEMENTS

ParametersResistance: 0.001 Ohms

Inductance: 0.005 HCapacitance: 1e-6 F

2) 3-PHASE RLC SERIESELEMENTS

ParametersResistance: 150 OhmsInductance: 1e-3 HCapacitance: 1e-6 F

FAULT CREATED

Three Phase FaultTime Duration 0.2-0.3sFault Resistance 0.66 Ohm

SUBSYSTEM PARAMETERS

PWM GENERATOR

3-Arm Bridge (6 Pulses)

Carrier Frequency 1080Hz

Sample Time 50-6

UNIVERSAL BRIDGE

No. Of Arms 3Snubber Resistance: 148.4 OhmsSnubber Capacitance: InfinityPower Electronic Devices Used:IGBT/Diodes

DC Voltage5KV DC Supply

Table 4.1 Simulation Parameters

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Powergui

-Continuous

+

-v

Voltage Measurement7

+

-v


+

-v

Voltage M easurement5

+

-v


+

-v


+

-v


+

-v


+

-v

Voltage Measurement

A

B

C

a

b

c

Three-phase

Transformer

(Two Windings)1

A

B

C

a

b

c

Three-phase

Transformer

(Two Windings)

A

B

C

A

B

C

Vabc

Three-Phase

V-I Measurement

A

B

C

a2

b2

c2

a3

b3

c3

Three-Phase

Transformer

(Three Windings)

Scope9

Scope8

Scope7

Scope6

Scope5

Scope4

Scope3

Scope2

Scope1

Linear Transformer2Linear Transformer1Linear Transformer

In1

In2

In3

In4

DVR

+i

-

+i

-

+i

-

Breaker2

Breaker1

Breaker

A

B

C

3-Phase SourceA

B

C

Fault

ABC

3-Phase Fault

A

B

C

A

B

C

3-Phase

SeriesRLC Branch 3

A

B

C

A

B

C

3-Phase

SeriesRLC Branch 2

A

B

C

A

B

C

3-Phase

SeriesRLC Branch 1

A

B

C

A

B

C

3-Phase

Series RLC Branch

Fig 4.3 Simulink Model of Dynamic Voltage Restorer

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CHAPTER5

HARDWARE DESCRIPTION

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5.1 COMPONENTS USED IN HARDWARE

5.1.1 PIC Microcontroller 16F870

Fig 5.1 Pin Diagram Of 16F870 Microcontroller

5.1.1.1 Pin configuration and description of PIC16F870

PIN NAME DIPPIN#

SOIC

PIN#

I/O/P

TYPE

BUFFER

TYPE

DESCRIPTION

OSC1/CLKI 9 9 1 ST/CMOS Oscillator crystal

input/external clocksource

OSC2/CLKO 10 10 O - Oscillator crystal outputin crystal oscillatormode. In RC mode, theOSC2pin outputsCLKO, which has the frequency of OSC1,and denotes the

instruction cycle

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MCLR/VPP/THV

1 1 I/P ST Master Clear (Reset)input or programmingvoltage input or highvoltage test mode

control. This pin is anactive low RESET tothe device.

RA0/AN0

RA1/AN1

RA2/AN2/VREF-

RA3/AN3/VREF+

RA4/T0CKI

RA5/AN4

2

3

4

5

6

7

2

3

4

5

6

7

I/O

I/O

I/O

I/O

I/O

I/O

TTL

TTL

TTL

TTL

ST/OD

TTL

RA0 can also be analoginput 0.RA1 can also be analoginput 1.RA2 can also be analoginput 2 or negative

analog referencevoltage.RA3 can also be analoginput 3or positiveanalog referencevoltage.RA4 can also be theclock input to the Timer0 module. Output isopen drain type.RA5 can also be analoginput 4

RB0/INT

RB1RB2RB3/PGM

RB4

RB5

RB6/PGC

21

222324

25

26

27

21

222324

25

26

27

I/O

I/OI/OI/O

I/O

I/O

I/O

TTL/ST

TTLTTLTTL/ST

TTL

TTL

TTL/ST

RB0 can also be theexternal interrupt pin.

RB3 can be the lowvoltage programming

input.

Interrupt-on-changepin.Interrupt-on-changepin.Interrupt-on-change pinor In-circuit Debuggerpin.Serial programming

data.

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RB7/PGD 28 28 I/O TTL/ST Interrupt-on-change pinor In-circuit Debuggerpin.Serial programmingdata.

RC0/T1OSO/T1CKI

RC1/T1OSI

RC2/CCP1

RC3RC4RC5RC6/TX/CK

RC7/RX/RT

11

12

13

14151617

18

11

12

13

14151617

18

I/O

I/O

I/O

I/OI/OI/OI/O

I/O

ST

ST

ST

STSTSTST

ST

RC0 can also be theTimer1oscillator outputor Timer 1 clock input.

RC1 can also be theTimer1 oscillator input.

RC2 can also be theCapture1input/Compare

1 output/PWM1 output.

RC6 can also be theUSART AsynchronousTransmit orSynchronous Clock.RC7 can also be theUSART AsynchronousReceive orSynchronous Data.

VSS 8,19 8,19 P - Ground reference forlogic and I/O pins

VDD 20 20 P - Positive supply forlogic and I/O pins.

TABLE 5.1 PIC16F870 Pin Configuration and Description

Legend: I = input O = output input/output P = powerOD = OpenDrain

= Notused

TTL = TTLinput

ST = Schmitt

Trigger input

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5.1.2 7085 Voltage Regulator IC

Fig 5.2 7085 Voltage Regulator

7805 is a voltage regulator integrated circuit. It is a member of 78xx

series of fixed linear voltage regulator ICs. Voltage source in a circuit may have

fluctuations and would not give the fixed voltage output. The voltage regulator IC

maintains the output voltage at a constant value. The xx in the 78xx indicates the fixedoutput voltage it is designed to provide. 7805 provides +5V regulated power supply.

Capacitors of suitable values can be connected at input and output pins depending

upon the respective voltage levels.

5.1.3 IRF840 MOSFET

Fig 5.3 IRF840

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5.1.3.1 Features

Dynamic dV/dt Rating

Repetitive Avalanche Rated

Fast Switching

Ease of Paralleling

Simple Drive Requirements

Compliant to RoHS Directive 2002/95/EC

5.1.3.2 Description

Third generation Power MOSFETs provide the designer with the best

combination of fast switching, ruggedized device design, low on-resistance and cost-

effectiveness. The TO-220AB package is universally preferred for all commercial-

industrial applications at power dissipation levels to approximately 50 W. The low

thermal resistance and low package cost of the TO-220AB contribute to its wideacceptance throughout the industry.

5.1.4 SK 100B Transistor

Fig 5.4 SK 100B

DEVICE SPECIFICATION

Type : SK100 Polarity : P N P Application : General

Purpose Medium Power

Transistor

PACKAGE : TO-39

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5.1.5 Optocoupler MCT2E

Fig 5.5 MCT2E

5.1.6 Transistor 2N2222A

Fig 5.6 2N2222A

Gallium Arsenide DiodeInfrared Source. OpticallyCoupled to a Silicon npnPhototransistor.

High Direct-CurrentTransfer Ratio. Base LeadProvided forConventional TransistorBiasing.

High-Voltage ElectricalIsolation 1.5-kV, or 3.55-kV Rating. Plastic Dual-In-Line Package.

High-Speed Switching: tr= 5 s, tf = 5 s

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PIN DESCRIPTION

1 emitter

2 base

3 collector, connected to case

Table 5.2 Pin Description of 2N2222A

5.1.7 Liquid Crystal Display (LCD)

Fig 5.7 LCD Display JHD 162A

5.1.7.1 Pin Configuration

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

VS

S

VC

C

VE

E

R

S

R/

W

E

DB

0

DB

1

DB

2

DB

3

DB

4

DB

5

DB

6

DB

7

LE

D+

LE

D-

Table 5.3 Pin Configuration of JHD 162A

A general purpose alphanumeric LCD, with two lines of 16 characters.LCDs

with a small number of segments, such as those used in digital watches and pocket

calculators, have individual electrical contacts for each segment. An external
http://en.wikipedia.org/wiki/Alphanumerichttp://en.wikipedia.org/wiki/Digital_watchhttp://en.wikipedia.org/wiki/Pocket_calculatorhttp://en.wikipedia.org/wiki/Pocket_calculatorhttp://en.wikipedia.org/wiki/Pocket_calculatorhttp://en.wikipedia.org/wiki/Pocket_calculatorhttp://en.wikipedia.org/wiki/Digital_watchhttp://en.wikipedia.org/wiki/Alphanumeric

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dedicated circuit supplies an electric charge to control each segment. This display

structure is unwieldy for more than a few display elements.

Small monochrome displays such as those found in personal organizers, or olderlaptop screens have a passive-matrix structure employing super-twisted nematic (STN)

or double-layer STN (DSTN) technologythe latter of which addresses a color-

shifting problem with the formerand color-STN (CSTN)wherein color is added

by using an internal filter. Each row or column of the display has a single electrical

circuit. The pixels are addressed one at a time by row and column addresses. This type

of display is called passive-matrix addressedbecause the pixel must retain its state

between refreshes without the benefit of a steady electrical charge. As the number of

pixels (and, correspondingly, columns and rows) increases, this type of display

becomes less feasible. Very slow response times and poor contrast are typical of

passive-matrix addressed LCDs

5.2 BLOCK DIAGRAM

Fig 5.8 Block diagram of DVR hardware
http://en.wikipedia.org/wiki/Electronic_circuithttp://en.wikipedia.org/wiki/Laptophttp://en.wikipedia.org/wiki/Super-twisted_nematic_displayhttp://en.wikipedia.org/wiki/Response_time_%28technology%29http://en.wikipedia.org/wiki/Display_contrasthttp://en.wikipedia.org/wiki/Display_contrasthttp://en.wikipedia.org/wiki/Response_time_%28technology%29http://en.wikipedia.org/wiki/Super-twisted_nematic_displayhttp://en.wikipedia.org/wiki/Laptophttp://en.wikipedia.org/wiki/Electronic_circuit

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As shown in the block diagram the line voltage is sensed by the potential

transformer and the sensed voltage is then given to the signal conditioning circuit in

which sensor signals must be normalized and filtered to levels suitable for analog-to-

digital conversion so they can be read by computerized devices.

After the passing through the signal conditioning circuit the sensed signal is given to

the microcontroller in which the artificial neural networks algorithm takes care of the

PWM signal which is the output of the microcontroller. These PWM signals are used

as the gate trigger pulses. Before they are used for the mosfet gate the PWM pulses are

given to the gate driver circuit for amplification purpose. These pulses are then used as

the firing pulses for the gates of the mosfet devices used in the inverter circuit. The

output from the inverter circuit is then given to the injection/boost transformer which

is in series with the line. The necessary voltage is then injected into the line.

5.3 HARDWARE DESCRIPTION

Fig 5.9 Hardware Snapshot of DVR

POWER SUPPLY

FOR INVERTER

POWERSUPPLY TO

DRIVE CKT AND

MICROCONTROLLER

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5.3.1 Signal Conditioning Circuit

Fig 5.10 Signal Conditoning Circuit

In electronics, signal conditioning means manipulating an analogue signal in

such a way that it meets the requirements of the next stage for further processing.

Most common use is in analog-to-digital converters. In control engineering

applications, it is common to have a sensing stage (which consists of a sensor), a

signal conditioning stage (where usually amplification of the signal is done) and a

processing stage (normally carried out by an ADC and a micro-controller).

Operational amplifiers (op-amps) are commonly employed to carry out the

amplification of the signal in the signal conditioning stage.

5.3.1.1 Signal Conditioning Circuit Inputs

The input to the signal conditioning circuit is an AC voltage which produces the

respective output voltage.

1

2 3

4

1. Diodes IN40042. Potentiometer 10K3.

Capacitor 1000uf

4. Zener Diode
http://en.wikipedia.org/wiki/Analogue_signalhttp://en.wikipedia.org/wiki/Analog-to-digital_converterhttp://en.wikipedia.org/wiki/Control_engineeringhttp://en.wikipedia.org/wiki/Sensorhttp://en.wikipedia.org/wiki/Analog-to-digital_converterhttp://en.wikipedia.org/wiki/Micro-controllerhttp://en.wikipedia.org/wiki/Operational_amplifiershttp://en.wikipedia.org/wiki/Operational_amplifiershttp://en.wikipedia.org/wiki/Micro-controllerhttp://en.wikipedia.org/wiki/Analog-to-digital_converterhttp://en.wikipedia.org/wiki/Sensorhttp://en.wikipedia.org/wiki/Control_engineeringhttp://en.wikipedia.org/wiki/Analog-to-digital_converterhttp://en.wikipedia.org/wiki/Analogue_signal

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5.3.1.2 Applications of Signal Conditioning Circuit

It is primarily utilized for data acquisition, in which sensor signals must be

normalized and filtered to levels suitable for analog-to-digital conversion so they canbe read by computerized devices. Other uses include preprocessing signals in order to

reduce computing time, converting ranged data to boolean values, for example when

knowing when a sensor has reached certain value. Types of devices that use signal

conditioning include signal filters, instrument amplifiers, sample-and-hold amplifiers,

isolation amplifiers, signal isolators, multiplexers, bridge conditioners, analog-to-

digital converters, digital-to-analog converters, frequency converters or translators,

voltage converters or inverters, frequency-to-voltage converters, voltage-to-frequency

converters, current-to-voltage converters, current loop converters, and charge

converters.

5.3.2 Gate Driver Circuit

Fig 5.11 Gate Driver Circuit

1 2 34

2

1 2 3

4

2

1. MCT 2E Optocoupler2. SK 100B Transistor3. 2N2222A Transistor4. 1000uF capacitor
http://en.wikipedia.org/wiki/Data_acquisitionhttp://en.wikipedia.org/wiki/Instrument_amplifierhttp://en.wikipedia.org/wiki/Sample-and-holdhttp://en.wikipedia.org/wiki/Isolation_amplifierhttp://en.wikipedia.org/w/index.php?title=Signal_isolator&action=edit&redlink=1http://en.wikipedia.org/wiki/Multiplexerhttp://en.wikipedia.org/w/index.php?title=Bridge_conditioner&action=edit&redlink=1http://en.wikipedia.org/wiki/Analog-to-digital_converterhttp://en.wikipedia.org/wiki/Analog-to-digital_converterhttp://en.wikipedia.org/wiki/Digital-to-analog_converterhttp://en.wikipedia.org/wiki/Frequency_converterhttp://en.wikipedia.org/wiki/Voltage_converterhttp://en.wikipedia.org/wiki/Inverter_%28electrical%29http://en.wikipedia.org/w/index.php?title=Frequency-to-voltage_converter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Voltage-to-frequency_converter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Voltage-to-frequency_converter&action=edit&redlink=1http://en.wikipedia.org/wiki/Current-to-voltage_converterhttp://en.wikipedia.org/w/index.php?title=Current_loop_converter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Charge_converter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Charge_converter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Charge_converter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Charge_converter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Current_loop_converter&action=edit&redlink=1http://en.wikipedia.org/wiki/Current-to-voltage_converterhttp://en.wikipedia.org/w/index.php?title=Voltage-to-frequency_converter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Voltage-to-frequency_converter&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Frequency-to-voltage_converter&action=edit&redlink=1http://en.wikipedia.org/wiki/Inverter_%28electrical%29http://en.wikipedia.org/wiki/Voltage_converterhttp://en.wikipedia.org/wiki/Frequency_converterhttp://en.wikipedia.org/wiki/Digital-to-analog_converterhttp://en.wikipedia.org/wiki/Analog-to-digital_converterhttp://en.wikipedia.org/wiki/Analog-to-digital_converterhttp://en.wikipedia.org/w/index.php?title=Bridge_conditioner&action=edit&redlink=1http://en.wikipedia.org/wiki/Multiplexerhttp://en.wikipedia.org/w/index.php?title=Signal_isolator&action=edit&redlink=1http://en.wikipedia.org/wiki/Isolation_amplifierhttp://en.wikipedia.org/wiki/Sample-and-holdhttp://en.wikipedia.org/wiki/Instrument_amplifierhttp://en.wikipedia.org/wiki/Data_acquisition

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The gate driver circuit is used for the amplification of the PWM output obtained

from the microprocessor. Since the PWM output is of low magnitude the gate driver

circuit is used with transistors in amplification mode to give the required firing angle

pulses to the MOSFET gate.

5.3.3 Microcontroller and PWM Generator Circuit

Fig 5.12 Snap Shot of Microcontroller and PWM Generator Circuit

This circuit is the main part of DVR hardware the PIC controller is used to

sense the PT voltage and produce PWM pulses of the required width to ensure that the

line voltage is compensated. The crystal oscillator is used for constant 4MHz

operation of the PIC controller. The 7805 IC is used to give a constant 5V supply to

the PIC microcontroller for working.

1

2 3

4 7 5

6

8

1. RESET SWITCH2. IC 78053. PIC16F8704. 1000uF Capacitor5. 0.01pF Capacitor6. POT7. Crystal Oscillator 4MHz8. JHD162A LCD Display

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CHAPTER 6

SIMULATION AND HARDWARE RESULTS AND DISCUSSION

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6.1 SIMULATION RESULTS

6.1.1 VOLTAGE SAG

Fig 6.1.1 (a) Output of system with Sag

Fig 6.1.1 (b) Injected Voltage from DVR

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Fig 6.1.1 (c) System Output After Sag Compensation By DVR

The first simulation shows three phase voltage sag. The Figure 6.1.1 (a) shows a

15% voltage sag initiated at 0.20s and it is kept until 0.30s, with total voltage sag

duration of 0.10s. Figure 6.1.1 (b) shows the voltage injected by the DVR to

compensate the voltage sag produce in the system. The DVR injects a voltage of

0.15pu, during the time 0.20s to 0.30s, in phase with the line voltage. Figure 6.1.1 (c)

shows the load voltage with compensation. As a result of DVR, the load voltage is

kept at 1 pu.

The voltage parameters before and after compensation are as follows:

Parameters Before Compensation

Voltage Of Normal System15.55KV Voltage At Time 0.20s To 0.30s13KV Voltage Sag Value2.55KV

Parameters Of Injected Voltage

Voltage During Time 0.20s < Time > 0.30s0KV Voltage During Time 0.20s To 0.30s2.55KV

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Parameters After Compensation

Voltage Of The System For Time > 015.55KV6.1.2 VOLTAGE SWELL

Fig 6.1.2 (a) Output of system with Swell

Fig 6.1.2 (b) Injected Voltage from DVR

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Fig 6.1.1 (c) System Output After Swell Compensation By DVR

The first simulation shows three phase voltage sag. The Figure 6.1.2 (a) shows a

16% voltage swell initiated at 0.20s and it is kept until 0.30s, with total voltage swell

duration of 0.10s. Figure 6.1.2 (b) shows the voltage injected by the DVR to

compensate the voltage swell produce in the system. The DVR injects a voltage of

0.6pu, during the time 0.20s to 0.30s, which is opposite to the line voltage. Figure6.1.2 (c) shows the load voltage with compensation. As a result of DVR, the load

voltage is kept at 1 pu.

The voltage parameters before and after compensation are as follows:

Parameters Before Compensation

Voltage Of Normal System15.55KV Voltage At Time 0.20s To 0.30s25.55KV Voltage Swell Value10KV

Parameters Of Injected Voltage

Voltage During Time 0.20s < Time > 0.30s0KV

Voltage During Time 0.20s To 0.30s10KV

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Parameters After Compensation

Voltage Of The System For Time > 015.55KV6.2 HARDWARE RESULTS

Fig 6.2 (a) PWM Pulses Generated by The PIC Microcontroller

Fig 6.2 (b) Voltage Output With Sag

1 PU

0.56

0.0

-0.56

-1.0

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0s

1V

0

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9s

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Fig 6.2 (c) Voltage Injected by the DVR

Fig 6.2 (d) Compensated Voltage Output

The figure 6.2 (a) shows the PWM pulses which are the output of the PIC

microcontroller for the corresponding sag produced in the system as shown in figure

6.2 (b) .The figure 6.2 (b) shows the output voltage of hardware as 0.56pu. This is due

to the sag produced in the system. The DVR then injects a voltage of 0.44pu to make

the output as 1pu. The injected voltage is shown in the figure 6.2 (c) indicating voltage

of 0.44pu. the figure 6.2 (d) shows the compensated normal voltage of the system with

1pu voltage output

0.44pu

0

-0.44

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9s

1 pu

0

-1pu

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9s

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CHAPTER 7

CONCLUSION AND FUTURE WORK

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CONCLUSION

The power quality problems prevalent in the industries have been discussed and

a custom power device called Dynamic Voltage Restorer is simulated and

implemented. The control technique adopted has been discussed. This Dynamic

Voltage Restorer is more efficient in mitigating the voltage sags and swells. From the

simulation and hardware results it is found that the DVR can handle both sag and

swell very effectively and respond in a faster manner.

FUTURE WORK

To design a neural network controller with un-supervised learning. To enhance the performance of DVR with better energy storage devices. To implement multi level inverter in the existing system.

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APPENDIX - I

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BLOCK DIAGRAM OF MICRO CONTROLLER

PIC 16F870

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PIC 16F870 Register File Map

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PIC 16F870 Key Features

ELECTRICAL CHARACTERISTICS

Absolute Maximum Ratings Ambient temperature under bias : -55 to +125C

Storage temperature : 65C to +150C

Voltage on any pin with respect to VSS (except VDD, MCLR. and RA4) : 0.3V to

(VDD + 0.3V)

Voltage on VDD with respect to VSS : -0.3 to +7.5V

Voltage on MCLR with respect to VSS (Note 2) : 0 to +13.25V

Voltage on RA4 with respect to Vss : 0 to +8.5V

Total power dissipation (Note 1) : 1.0W

Maximum current out of VSS pin : 300 mA

Maximum current into VDD pin : 250 mA

Input clamp current, IIK (VI < 0 or VI > VDD): 20 mA

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Output clamp current, IOK (VO < 0 or VO > VDD) : 20 mA

Maximum output current sunk by any I/O pin : 25 mA

Maximum output current sourced by any I/O pin : 25 mA

Maximum current sunk by PORTA, PORTB : 200 mA

Maximum current sourced by PORTA, PORTB : 200 mA

Maximum current sunk by PORTC : 200 mA

Maximum current sourced by PORTC : 200 Ma

PERIPHERAL FEATURES:

Timer 0: 8-bit timer / counter with 8-bit prescaler

Timer 1: 16 bit timer / counter with prescaler, can be incremented during sleep via

external crystal/clock

Timer 2: 8 bit timer / counter with 8 bit period register, prescaler and postscaler

Two capture, compare, PWM modules

Capture is 16 bit, max. resolution is 12.5 ns

Compare is 16 bit, max. resolution is 200 ns,PWM max. resolution is 10 bit

12 bit multi channel Analog-to Digital converter

On-chip absolute band gap voltage reference generator

Synchronous Serial Port (SSP) with SPI (Master Mode) and I 2 C

Universal Synchronous Asynchronous Receiver Transmitter, supports high / low

speeds and 9 bit address mode (USART/SCI)Parallel Slave Port (PSP) 8 bits wide, with external RD, WR and CS controls

Programmable Brown out detection circuitry for Brownout Reset (BOR)

Programmable Low-voltage detection circuitry

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MOSFET IRF840 RATINGS

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TRANSISTOR 2N2222A SPECIFICATIONS

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ELECTRICAL CHARATERISTICS OF MCT2E OPTOCOUPLER

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APPENDIX II

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PROGRAM TO CREATE AND TRAIN NEURAL NETWORK CONTROLLER

load po;

load pon;load pond;

a1=po1(2,:);a2=pon1(2,:);

b1=pond1(2,:);

P=[a1; a2]; % Input to NNT=b1; % Output to NN

% input1=input1(:,1);% output=output(:,1);

vl=[min(a1) max(a1)]; % min and max values of above datasv2=[min(a2) max(a2)];

net=newff([vl; v2],[2 1],{ 'tansig' 'purelin'}); % new feed forward network

net.trainparam.show=10; % Display show of epochsnet.trainparam.lr=0.01; % learning ratenet.trainparam.mc=0.9; % momentum of BPnet.trainparam.epochs=1000; % No. of training epochsnet.trainparam.goal=1e-5; % Error goalnet=train(net,P,T); % Training of NNy=sim(net,P); % simulation of trained NNgensim(net,.01)%,'trainscg'

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REFERENCES

1. R. H. Salimin, M. S. A. Rahim, Simulation Analysis of DVR Performance forVoltage Sag Mitigation, The 5th International Power Engineering and

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