HARDWARE AND SIMULATION OF HVDC WITH REAL TIME USER INTERFACE BATCH: 2013-2014 SECTION: A GROUP NO: 20 GROUP MEMBERS: Zahoor Hassan EE- 023 Syed… [617280]

Final Year Project

HARDWARE AND SIMULATION OF HVDC WITH REAL
TIME USER INTERFACE

BATCH: 2013-2014

SECTION: A

GROUP NO: 20

GROUP MEMBERS:

Zahoor Hassan EE- 023
Syed Hassan Afsar EE- 029
Umerullah Khan Shirazi EE- 059
Khubbab Ejaz EE- 085

Department of Electrical Engineering
NED University of Engineering & Technology

i

TABLE OF CONTENTS
Page
TABLE OF CONTENTS ii
LIST OF FIGURES iv
LIST OF TABLES v
ACKNOWLEDGEMENT vi
ABSTRACT vii
CHAPTER ONE : INTRODUCTION
1.0 Overview 1
1.1 Generation Substation 1
1.2 Three Phase Rectifier 2
1.3 HVDC Transmission Line 2
1.4 Three Phase Inverter 2
1.5 Transmission Substation 2
CHAPTER TWO :
2.0 Introduction to HVDC 4
2.1 HVDC Advantages Over HVAC 5
2.2 Types of HVDC Systems 7
2.2.1 MONO Polar Link 7
2.2.2 Bipolar Link 8
2.2.3 Homo Polar Link 9
2.3 Practical Examples of HVDC System 9
2.3.1 Biswanth – AGRA India 9
2.3.2 Three Gorges China 10
2.3.3 Xiangjiaba – Shanghai HVDC System 10
CHAPTER THREE: METHODOLOGY
3.0 Electrical Circuit Design 11
3.1 Mechanical Design 11
3.2 Gantt Chart 12
CHAPTER FOUR: MODULE DESCRIPTION

ii

4.0 General Calculations 13
4.0.1 Power 13
4.0.2 Transformer 13
4.0.3 Rectifier 14
4.0.4 DC Transmission Line 15
4.0.5 Three Phase Inverter 15
4.0.6 Load 15
4.0.7 Voltage & Current at Different Points 16
4.1 Generation Substation 16
4.1.1 Mechanical Design 17
4.2 Three Phase Rectifier 18
4.2.1 Electrical Design 18
4.2.2 DC Filter 20
4.2.3 Mechanical Design 24
4.3 Transmission Line 25
4.3.1 Mechanical Design 25
4.5 Three Phase Inverter 26
4.5.1 Electrical Design 26
4.5.2 Mechanical Design 27
4.5.4 Filter Design for PWM Inverter 28
4.6 Transmission Substation 29
4.6.1 Voltage & Current Ratings 29
4.6.2 Mechanical Design 29
4.7 Load 30
4.7.1 Mechanical Design 30

CHAPTER FIVE : TESTING
5.0 Test 1 31
5.1 Test 2 32

CHAPTER SIX – COST 33
CHAPTER SEVEN – CONCLUSION 34
CHAPTER EIGHT – RECOMENDATIONS 35

REFERENCE 36

iii

LIST OF FIGURES

1.1 Single Line Diagram of the HVDC System 3
1.2 MONO Polar HVDC Link 3
2.1 HVAC vs. HVDC Cost Compared 7
2.2 MONO Polar Link Line Diagram 7
2.3 Bipolar Link Line Diagram 8
2.4 Homo Polar Link Line Diagram 9
2.5 Biswanath India HVDC Line Diagram 9
2.6 Three Gorges China HVDC 10
4.1 HVDC Link Line Diagram 16
4.2 Acrylic Design of Generation Substation 17
4.3 Proteus Circuit Design of Three Phase Rectifier 18
4.4 MULTISIM Simulation of Three Phase Rectifier 18
4.5 PCB Layout of Three Phase Rectifier 19
4.6 PCB of Three Phase Rectifier 19
4.7 LC Filter 20
4.8 RLC Filter 21
4.9 Three Phase Rectifier with RLC Filter 23
4.10 Three Phase Rectifier Testing 23
4.11 Acrylic Design of Three Phase Rectifier 24
4.12 Acrylic Design of Transmission Line 25
4.13 PROTEUS Circuit Design of Three Phase Inverter 26
4.14 Acrylic Design of Three Phase Inverter 27
4.15 Acrylic Design of Transmission Substation 29
4.16 Acrylic Design of Three Phase Load 30
5.0 Transformer Testing (i) 31
5.1 Transformer Testing (ii) 32
5.2 Rectifier Testing 32

iv

LIST OF TABLES

3.1 Gantt Chart 12
4.1 Voltage & Current Values 16
6.1 Total Cost 33

v

ACKNOWLEDGEMENT

First and foremost we are grateful to the almighty Allah, the Most Gracious and Most
Merciful for ensuring our health to carry out our studies, and to complete this project with
the best of our abilities.
We would like to take this opportunity to express our heartfelt gratitude for our project
advisor Sir Saddam Hussain, who provided us with valuable inputs at the critical stages of
this project execution. He inspired us greatly and his willingness to motivate us contributed
tremendously to our project. We are highly indebted to Sir Furqan, Sir Mohsin Aman and
all the members of the final year project committee for having faith in our abilities and
giving us the opportunity to execute our idea. The project would not have taken shape
without their guidance, constant supervision and direction. We are also grateful to the
Department of Electrical Engineering,

NED University of Engineering and Technology, for providing us with a good environment
and facilities to complete this project.
Words cannot express how grateful we are to our parents for providing continuous guidance
and wholehearted support throughout the project and for all of the sacrifices that they have
made on our behalf. Their prayer for us was what sustained us this far. Finally, an
honorable mention goes to all the staff of electrical engineering department. We would like
to express our deepest appreciation to Sir Saddam Hussain for cooperating with us during
the course of our project.
Zahoor Hassan EE-023
Syed Hassan Afsar EE-029
Umerullah Khan Shirazi EE-059
Khubbab Ejaz EE-085

vi

HARDWARE AND SIMULATION OF HVDC WITH REAL
TIME USER INTERFACE

ABSTRACT

The HVDC Transmission training system is designed to provide students with an in-depth
understanding of the fundamentals of three-phase DC power transmission, as it allow fast
and precise control of the amount of power transmitted between critical nodes of the grids.
Comprising of an integrated modular interface, it can provide hands-on experience and
familiarize engineering students with the power losses involved, practical working, and
operation of DC power circuits, power transformer along with modern power electronic
devices based on preferred pedagogical practices

vii

CHAPTER ONE

INTRODUCTION

1.0 OVERVIEW

HVDC trainer is meant for students to help them understand the concept of HVDC
transmission by modeling it on a trainer. This project mainly consists of seven units
Generation, Three Phase Rectifier, DC transmission line, Three Phase Sinusoidal Inverter,
Transmission substation, Instrumentation & Three Phase Load. It signifies the importance
of low losses in DC transmission rather than AC transmission over long distances.

We have designed our trainer at 500VA rating. Due to safety reasons we have scaled do wn
voltage levels and subsequent current levels by a factor of 2500. Hence if the transmission
line was transmitting at 25KV then applying the scaling factor we get 25K/2500=10V and
so on for other values.

In our project we have six individual units which can be used as an individual entities, and
when all integrated in order they model a HVDC transmission system. These six units are:

 Generation Substation
 Three phase rectifier
 HVDC transmission line
 Buck Boost Converter
 Three phase inverter
 Substation
 Load
 Instrumentation box

1

Chapter 1 Introduction

1.1 GENERATION SUBSTATION
This unit is followed by the power generation. The Generation substation steps up the
voltage level for transmission. In our project this is modeled by a three phase transformer
which takes normal three phase supply from KE (Karachi Electric) at 380V and steps out at
150V, in principle it means that when power was produced at 25KV which when stepped
down by 2500 factor represents 10V then comes the primary substation which steps it up by
a ratio of 15 i.e. 25KV stepped up to 375KV and subsequently on a scaled down level 10V
to 150V.

1.2 THREE PHASE RECTIFIER
This section represents the converter station, which rectifies 375KV AC to 500KV DC.
This on a scaled down version seems like 150V AC to 200V DC.

1.3 HVDC TRANSMISSION LINE
This unit depicts a mono-polar HVDC link carrying 200V DC, it is passed through different
specifically designed circuits which represent different distance of transmission line s
mapping over thousands of kilometers by each having a specific resistance.

1.4 BUCK BOOST
We will be using a buck boost converter in this circuit to make the input side more
controllable by the user in real time user can increase and decrease the voltage leve l
according to its requirements.

1.5 THREE PHASE INVERTER
Three phase inverter inverts the DC to AC. This is achieved by the pulse width modulation
(PWM) technique. It models the converter installed at the distribution end. It converts 200V
DC back to 150V AC.

1.5 TRANSMISSION SUBSTATION
This substation is used to step down the AC voltage to a level which is safely usable by the
end user. In this case this is 380V AC.

2

Chapter 1 Introduction

The following figure shows a single line diagram of the HVDC System, which is
modeled in our project.

Figure 1.1: SINGLE LINE DIAGRAM OF THE HVDC SYSTEM

The following diagram represents a mono-polar HVDC link as it is implemented
practically.

Figure 1.2: MONO POLAR HVDC LINK

3

Chapter 2 Literature Review

CHAPTER TWO

LITERATURE REVIEW

2.0 INTRODUCTION TO HVDC TRANSMISSION

High Voltage, Direct Current is a kind of electric power transmission. In this system direct
current (DC) is used for transmission rather than the conventional alternating current (AC).
As compared to the AC transmission HVDC is of low cost and suffers low electrical losses
after a threshold distance. In AC transmission systems when power is transmitted under
water, the current needs to be high in order to overcome the charging and discharging of
the cables in each cycle, while in DC transmission that is not necessary due to the nature of
DC.

HVDC transmission basically comprises of six units that are:

 Primary substation
 Three phase rectifier
 Transmission
 Buck Boost Converter
 Three phase inverter
 Secondary substation

4

Chapter 2 Literature Review

2.1 HVDC ADVANTAGES OVER HVAC

 HVDC is more feasible for longer distances as compared to HVAC, because
when these cables are undergrounded for longer than 65 KM different factors
act up and increase the losses in HVAC. Whenever wires are installed
capacitance is a factor that acts, while a wire suspended in air has much less
capacitance (by about a factor of 50-100) than a cable in which it is surrounded
by soil and polymeric insulation. The capacitance commands the time the cable
takes to deliver voltage at the other end of cable when voltage is applied, and so
the case that when DC is transmitted it is a constant voltage which does not vary
and hence the charging and discharging of the cable does not take place due to
the which is seen in the AC. At 50Hz the voltage reverses 100 times per second
(10 milliseconds for per reversal), and every time this happens the line
capacitance needs to be charged up to make any power flow through the cable.
Hence an AC underground transmission cable can be only placed for a shorter
distance while a DC underground transmission cable can be placed for a longer
distance without any problem with respect to power flow.
 When cables are selected for HVAC transmission there is only a certain range
for the wire diameter till which it can be selected due to “Skin Effect ” that
prevents an AC current flowing from center of a large diameter wire, whereas
DC line can be thick. Wires that are greater than an inch have a greater skin
effect at 50Hz. Due to this multiple wires are arranged in a circular design and
are separated by polymer spacers in HVAC transmission line. Hence overhead
HVDC power lines can transmit more power efficiently on longer distances
rather than HVAC.
 In HVAC transmission voltage can be taken up to as high as 765KV but above
that power dissipation becomes significant by dielectric losses. Dielectric loss

5

Chapter 2 Literature Review

quantifies a dielectric material ’s inherent dissipation of electromagnetic energy
into, e.g., heat. It can be parameterized in terms of either the loss angle δ or the
corresponding loss tangent tan δ. Both refer to the phasor in the complex plane
whose real and imaginary parts are the resistive (lossy) component of an
electromagnetic field and its reactive (lossless) counterpart. This is the basic
principle of microwave ovens. At high AC voltage, dielectric losses of non-
resistive power dissipation and corona discharge become significant. As far as
DC is concerned HVDC overhead power lines can have higher voltage levels as
compared to AC, currently the maximum HVDC lines voltage is 800KV. This
shows that HVDC can transmit twice as high as HVAC voltage.
 For AC power to be transmitted over different power networks there is an
important aspect which cannot be ignored that is the synchronization of power
and frequency, while HVDC can be used to link two different synchronized AC
grids that are not synchronized with each other. In HVAC the line power must
be synchronized with the local AC grid. Now HVDC is helpful in cases of
linking two different power networks, a practical example of this is in Japan,
where there are different regions of 50Hz & 60Hz power network. HVDC
power flow between separate AC systems can be automatically controlled to
provide support for either network during transient conditions, but without the
risk that a major power system collapse in one network will lead to a collapse in
the second.
 Depending on voltage level and construction details, HVDC transmission losses
are quoted to be about 3% per 1000km, which is less than typical losses in an
AC transmission system.
 If we consider the cost involved in making both systems HVAC & HVDC, then
we know that after a particular distance (break even distance) HVDC

6

Chapter 2 Literature Review

Transmission is the best choice. The following figure shows a comparison of the two:

Figure 2.1: HVAC VS HVDC COST COMPARED

2.2 TYPES OF HVDC SYSTEMS

2.2.1 MONO POLAR LINK
Mono polar link uses only a single conductor, while using ground in case of overhead lines
and sea in case of underwater cables as a return path.

Figure 2.2: MONO POLAR LINK LINE DIAGRAM

7

Chapter 2 Literature Review

2.2.2 BIPOLAR LINK

In Bipolar link we use two conductors one being the positive and second is negative. It is
expensive than Mono polar link as it has a return conductor, but Bipolar link has several
advantages over mono polar link:

 When there is normal load over the system, a negligible amount of current
flows through the return conductor. This reduces the losses that mono polar
faces due to earth return conductor and environmental effects.

 For a given power rating transmission system each conductor of a bipolar
line, it carries only half the current of mono polar lines, hence the cost of the
second conductor is reduced compared to a mono-polar line of the same
rating.

 In case of a fault in which one of the conductors fails in a bipolar link, we
can use the second conductor to in a mono polar configuration and still keep
the system running.

Figure 2.3: BIPOLAR LINK LINE DIAGRAM

8

Chapter 2 Literature Review

2.2.3 HOMO POLAR LINK

Homo polar links have two conductors having the same polarity. The return path for such a
system is through ground. Since the corona effect in DC transmission lines is less for
negative polarity, homo polar link is usually operated with negative polarity.

Figure 2.4: HOMO POLAR LINK LINE DIAGRAM

2.3 PRACTICAL EXAMPLES OF HVDC SYSTEM

2.3.1 BISWANA TH – AGRA, INDIA

This project has a transmission line voltage of 800KV, and a power capacity of 8000MW.
This system is mapped from North Eastern and Eastern region of India to Agra covering a
distance of 1728KM.

Figure 2.5: BISWANATH INDIA HVDC LINE DIAGRAM

9

Chapter 2 Literature Review

2.3.2THREE GORGES CHINA

This HVDC system uses a bipolar transmission line. It transmits electric power from Three
Gorges power plant to Changzhou it covers an approximate distance of 940 Km. The
transmission line voltages are 500KV and has a power rating of 3000MW.

Figure 2.6: THREE GORGES CHINA HVDC

2.3.3 XIANGJIABA – SHANGAI HVDC SYSTEM

It has an 800KV transmission line voltage and a power rating of 6400MW. It is mapped
over a distance of 1907 Km. It is a bipolar system with overhead lines. It transmits power
from Xiangjiaba Dam to Shanghai.

10

Chapter 3 Methodology

CHAPTER THREE

METHODOLOGY

Our project is basically divided in three parts

 Electrical design
 Mechanical design

These are further elaborated in this Chapter.

3.0 ELECTRICAL CIRCUIT DESIGN
Following steps were followed to complete this:
 Application diagram
 Line diagram
 Schematic Diagram
 Simulation using Proteus
 Components procurement
 Prototype Development
 Hardware Manufacture
 Initial testing
 Testing on load

3.1 MECHANICAL DESIGN
Mechanical design involves the following steps:
 Designing the body of trainer
 Designing individual modules

11

Chapter 3 Methodology

3.2 GANTT CHART

Task1: HVDC Basic Study 4 weeks
Task2: Study of software ’s 4 weeks
Task3: System designing 4 weeks
Task4: Body manufacturing 8 weeks
Task5: System integration 4 weeks
Task6: Testing and finalization 4 weeks
Report writing 2 weeks

TABLE 3.1: GANTT CHART

12Tasks Jan Feb March April May June July August Sept
Task1

EXAMS
Task2

Task3

Task4

Task5

Task6

Report Writing

Chapter 4 Project Description

CHAPTER FOUR

MODULE DESCRIPTION

4.0 GENERAL

4.0.1 POWER CALCULATIONS
As discussed earlier in Chapter 1 we have set our HVDC trainer at 500 watt at 0.8 power
factor. Now to accomplish this desired value of power we have to calculate values of
voltage and current at different levels throughout the system. We got custom made three
phase transformer of 625VA to achieve this.

4.0.2 TRANSFORMER
For a 625 VA transformer the following parameters were considered while designing them:

 Primary side input of 380V to secondary of 150V
 Y to Y connection at primary side while a delta connection at secondary
Side

𝐼 = 𝜇
ሺଵ.଻ଷ×௏× cosሺଷ଺ሻሻ 4.1

Input:
Vrms line =380 V rms
Vm line = 538.89 V m

Output:
Vrms line = 150 V rms
Vm line = (150 ×√ʹ) = 212.13 V m

13

Chapter 4 Project Description

Vrms phase = ଵହ଴
√ଷ = 86.6 V rms
Vm phase = 86.6 ×√ʹ = 122.47 V m

4.0.3 RECTIFIER
This is installed just before the transmission line, it is 6 pulse rectifier which rectifies from
150V line to line to 200V DC (150/0.707=212.6404, ~200V DC). So if the power was
generated at 10KV and transmitted at 200KV DC (High voltage DC transmission). To find
the current at input side.

𝐼s = ହ଴଴ ௐ
ሺଵ.଻ଷ×଴.଼× ଵହ଴ ሻ 4.2

Is=2.408 A line current and 2.5 A DC current.

Inputs:
Vm phase =122.47 V m
Vrms phase =86.6 V rms
Vrms line = 150 V rm
Vm line = 212.13 V m

Output:
Maximum output Voltage (average DC) for delay angle, α=0 is

𝑉݀𝑚 = ଷ√ଷ௏𝑚
𝜋 = = ଷ√ଷ
𝜋 (122.47) =202.56V 4.3

The RMS output of output voltage is

𝑉ݎ𝑚ݏ = √͵𝑉𝑚 ቀଵ
ଶ+ ଷ√ଷ
ସ𝜋cosʹ ∝ሻቁభ
మ = 202.74 𝑉 4.4

The system is designed at 500W. Thus average load current will be

14

Chapter 4 Project Description

𝑃ܥܦ = 𝐼ܥܦ × 𝑉ܥܦ 4.5
Rearranging
𝐼DC = 𝑃ವ಴
௏ವ಴= ହ଴଴
ଶ଴ଶ .଻ସ = 2.47 𝐴 4.6

Thus the average current through Thyristor is
𝐼A = ଶ.ସ଻
ଷ = 0.822 𝐴 4.7

The RMS current through a Thyristors
𝐼R = 0.822 √ଶ
଺ = 0.47 𝐴 4.8

The peak current through a Thyristor
𝐼PI = 0.822 𝐴 4.9

The peak inverse voltage is the peak amplitude of line to line voltage
𝑃𝐼𝑉 = √͵(122.47) = 212.12 𝑉 4.10

4.0.4 DC TRANSMISSION LINE
The line is a mono polar link. As it is 200V DC all the losses like corona, skin effect,
inductance & capacitance effects are ignored.

4.0.5 THREE PHASE INVERTER
This module comes after the transmission line where the DC is inverted by 3 – phase 120
degree conduction type inverter. The resultant voltage at the output of inverter is
Vout = (200/1.4141) = 145V line 3 phase. The frequency of the output is controlled by the
PWM provided to the MOSFET driver.

4.0.6 LOAD
The load that we have used is a 100W bulb on each phase in Y-configuration.

15

Chapter 4 Project Description

4.0.7 VOLTAGE & CURRENT AT DIFFERENT POINTS

TABLE 4.1: VOLTAGE & CURRENT VALUES

Point Voltage Current

A 380V 0.9507 A

B 10 V 28.9 A

C 10 V 28.9 A

D 150 V 2.408 A

E 150V 2.408 A

F 200 V DC 2.5 A

G 200 V DC 2.5 A

H 145 V 2.48 A

I 145 V 2.48 A

J 10 V 28.9 A

The table above is in correspondence with the diagram given below:

FIGURE 4.1: HVDC LINK LINE DIAGRAM

4.1 Generation Substation

From main board 380V line to line is received in Y configuration and give it to the
generation substation, which in terms represent a substation where power is generated. This
transformer is designed to step down primary side 380 V line to line to 150V line to line.
This module is only connected to external power.

16

Chapter 4 Project Description

4.1.1 Mechanical Design

We designed the face plate for the Generation Substation on Photoshop, following is its
diagram.

FIGURE 4.2: ACRYLIC DESIGN OF GENERATION SUBSTATION

17

Chapter 4 Project Description

4.2 Three Phase Rectifier
After the generation substation comes the second module that is the three phase rectifier.
This rectifies three phase 150V line to line into DC.

4.2.1 ELECTRICAL DESIGN
Following diagram represents the simulation of three phase rectifier:

FIGURE 4.3: PROTEUS CIRCUIT DESIGN OF THREE PHASE RECTIFIER

FIGURE 4.4: MULTISIM SIMULATION OF THREE PHASE RECTIFIER

18

Chapter 4 Project Description

FIGURE 4.5: PCB LAYOUT OF THREE PHASE RECTIFIER

FIGURE 4.6: PCB OF THREE PHASE RECTIFIER

19

Chapter 4 Project Description

4.2.2 DC FILTER

In order to smooth out the DC output of the rectifier a filter is required. We choose a LC
filter as in an RLC filter the resistor will cause a loss in power, and that is something we do
not desire.

DESIGN 1

FIGURE 4.7: LC FILTER

The input voltage is defined as VIN (t) =L

Vin(t) = L ௗ𝑖ሺ௧ሻ
ௗ௧+ଵ
𝐶∫𝑖ሺݐሻ ݐ݀ 4.11

Taking Laplace of this equation on both sides

Vin(S) = ( ݏ + )𝐼ሺௌሻ
𝐶௦ 4.12

VIN(S) = 200/s
(ݐ = )200 √𝐶
𝐿sin௧
√𝐿𝐶 4.13

Hence it is proved that current will keep on reversing its polarity. Current in the reverse
direction cannot flow from a rectifier diode and it will blow the circuit, so we cannot use
this LC filter and will have to use RLC filter.

20

Chapter 4 Project Description

DESIGN 2

FIGURE 4.8: RLC FILTER

As you can see a resistor has been introduced in this design but the load current does not
has to pass through the resistor, therefore reducing the power loss as compared to when the
resistor would be in series with the inductor.
According to KVL

Vin(t) = Lௗ𝑖ሺ௧ሻ
ௗ௧+𝑅𝑖ሺݐሻ+ଵ
𝐶∫𝑖ሺݐሻ ݐ݀ 4.14

Taking Laplace of this equation on both sides
Vin( ݏ = )𝐿ݏ𝐼(ݏ + )𝑅𝐼(ݏ + )𝐼ሺ௦ሻ
𝐶௦ 4.15

Assuming Vin(s) a step input function with peak value 200V so
VIN(s) = 200/s
ଶ଴଴
௦= {𝐿+ݏ 𝑅 +ଵ
𝐶௦} 𝐼ሺݏሻ 4.16

Simplifying
I(s) = ଶ଴଴
𝐿ቆଵ
ௌమ+𝑅
𝐿ௌ+భ
𝐿಴ቇ 4.17

To make the system critically damped, we have to consider its poles. By equating the
denominator to 0 and using quadratic formula, we find roots of s as follows:
S = −𝑅
𝐿±√𝑅మ
𝐿మ−ସభ
𝐿಴
ଶ 4.18

21

Chapter 4 Project Description

For making critically damped system, we equate
ோమ
𝐿 = ସ
𝐶 4.19

=ܥ ସ𝐿
ோమ 4.20
Substituting this value of C in the original equation of I(s) and simplifying

(ݏ = )ଶ଴଴
𝐿×ଵ
ቀௌ+𝑅
మ𝐿ቁమ 4.21
Taking Inverse Laplace Transform
𝑖ሺݐሻ= ଶ଴଴
𝐿݁ݐ−𝑅𝑡
మ𝐿 4.22

This equation shows that the current is not reversing its direction its direction so the
previous problem is solved. Now we find the peak value of by taking derivative of above
equation and equating it to 0.
𝑖ሺݐሻ= ଶ଴଴
𝐿݁ݐ−𝑅𝑡
మ𝐿ቀͳ −ோ௧
ଶ𝐿ቁ 4.23

Therefore t=2L/R is the value of time at which the peak occurs. Put this value of time to
find the peak value
Imax = ସ଴଴
ோ௘ 4.24

To limit the peak value of current to 1A, we found
𝑅 = 147Ω 4.25

Now the value of L can be calculated from the value of C
𝐿 = 𝐶ோమ
ସ 4.26

R=147Ω let C=10µF
L = 54.13 mH 4.27

22

Chapter 4 Project Description

The components we require for our filter are
L=54.13mH
C=10µF
R=147Ω

We have tested this design on Multisim Circuit Simulation Software and the results
matched our design as can be seen:

FIGURE 4.9: THREE PHASE RECTIFIER WITH RLC FILTER

FIGURE 4.10: THREE PHASE RECTIFIER TESTING

23

Chapter 4 Project Description

4.2.3 MECHANICAL DESIGN

Following is the application diagram and internal design that was followed in project.
Three phase rectifier will take supply via jumper connections from the generation
substation output.

FIGURE 4.11: ACRYLIC DESIGN OF THREE PHASE RECTIFIER

24

Chapter 4 Project Description

4.3 TRANSMISSION LINE
Once the three phase are rectified the DC bus is run through a number of resistors to model
the losses which a DC transmission line will face over a number of KMs.

4.3.1 MECHANICAL DESIGN

FIGURE 4.12: ACRYLIC DESIGN OF TRANSMISSION LINE

25

Chapter 4 Project Description

4.5 THREE PHASE INVERTER

The three phase inverter converts back the DC power to three phase AC power using s-
pulse bipolar scheme of PWM to switch the mosfets.

4.5.1 ELECTRICAL DESIGN

FIGURE 4.13: PROTEUS CIRCUIT DESIGN OF THREE PHASE INVERTER

26 Q1
IRC740
Q2
IRC740Q3
IRC740
Q4
IRC740Q5
IRC740
Q6
IRC740Q5(D)
R4
DC7Q3GND1VCC8
TR2TH6CV5U1
555R1
2.2k
C1
100nF
C2
10nFU1(VCC)
U1(R) L1
470uH3
214 11U1:A
LM3245
674 11U1:B
LM324
10
984 11U1:C
LM324
12
13144 11U1:D
LM324R1
10k
R2
10kR3
10k
R4
10k
R5
10k
R6
10kR7
10k
R8
10kR9
10kR10
5.6k
C1
1000nFU1:B(V+)
U1:C(V+)
U1:D(V+)U1:A(V+)
U1:A(V-)
U1:B(V-)
U1:D(V-)U1:C(V-)

Chapter 4 Project Description

4.5.2 MECHANICAL DESIGN

FIGURE 4.14: ACRYLIC DESIGN OF THREE PHASE INVERTER

27

Chapter 4 Project Description

4.5.4 Filter Design for Pulse Width Modulated Inverter

Basically, a filter, in this case has to have as low loss in power as possible and meet the
total harmonic distortion of five per cent maximum under 10% to 100% of full load voltage
applied to the load. Through mathematical calculations, designers are able to come up with
a low pass filter that far meets the specifications given. However, there are other factors to
consider like the use of readily available components to form the filter, cost optimization
and size minimization. When such factors are considered, designers are left with
compromises, which will influence their design and downplay the performance of the filter.
The first factor- meeting the specifications is on top of the priority list that affects the filter
design. Just consider the two main parameters that are of vital use to designers – maximum
total harmonic distortion as well as voltage output to the load. Now, the formula for total
harmonic distortion is as follows, THD in (%) = √(Vn2 + Vn+12 + Vn+22 + … )/ Vi x

100%, where Vn is the nth harmonic (exclude fundamental) voltage in RMS. Vi is
the fundamental harmonic voltage in RMS.

From the formula, we know that if the magnitude of fundamental harmonic voltage is
changed, THD will increase for a filter used in the inverter application. The remaining
harmonics will be roughly the same regardless of the magnitude of fundamental harmonic
voltage. This is vital when output voltage is variable from 10% to 100% of full-scale
voltage. Although the power loss of the filter is not mentioned in the specifications,
designers have to assume that the filter consumes power that is negligible relative to the
loads ’ due to the internal resistance of the inductor that forms the LC filter. Power loss of a
filter is related to its Q or quality factor and low power loss would indicate a high Q filter.
A Q factor of 20 is used in the filter design. Hence by calculating the values we arrived at
the calculated values of inductor=14.3mH & capacitor=4.5µF.

28

Chapter 4 Project Description

4.6 TRANSMISSION SUBSTATION

The transmission substation comprises of a three phase transformer which is designed to
step up voltage to a usable AC voltage of 380V line to line.

4.6.1 Voltage & Current Ratings

As this trainer is designed for 625VA power rating, so the transformer is designed with the
following ratings:

 150V/380V

 Y to Y connection

0.950/2.408A (i=p/(1.73V*cos 36))

4.6.2 MECHANICAL DESIGN

FIGURE 4.15: ACRYLIC DESIGN OF TRANSMISSION SUBSTATION

29

Chapter 4 Project Description

4.7 Load

Load that has been used in this module is Resistive Load, which are three, hundred watt
bulbs on each phase.

4.7.1 MECHANICAL DESIGN

FIGURE 4.16: ACRYLIC DESIGN OF THREE PHASE LOAD

30

Chapter 5 Testing

CHAPTER FIVE

TESTING

5.0 Test 1

The first test was conducted on the Generation Station module and the Transformer, which
went successful in the first try. Following images show the results:

In the following image it is shown that the input side line to line voltage of the transformer
is 408V.

FIGURE 5.1: TRANSFORMER TESTING (i)

31

Chapter 5 Testing

Following image shows that the output voltage of the transformer is 135.8V line to line

FIGURE 5.2: TRANSFORMER TESTING (ii)

5.1 Test 2
The second test was conducted on the Rectifier which was successful the output obtained
from the rectifier is shown in the following image:

FIGURE 5.3: RECTIFIER TESTING

32

Chapter 6 Cost

CHAPTER SIX

COST

TABLE 6.1 TOTAL COST

SR.NO HARDWARE COST

1 TRANSFORMERS 14,000

2 RECTIFIER 1500

3 INVERTER 3000

4 SHEET PRINTING 3500

5 CONNECTORS 1000

6 MISC 2000

TOTAL COST 25000

33

Chapter 7 Conclusion

CHAPTER SEVEN

CONCLUSION

The project is a trainer to be used in electrical machines Lab as reflecting the equipment
like:

 3-Phase Sinusoidal Inverter and its programming
 3-Phase Rectifier
 DC Transmission Lines
 3-Phase transformer
 Instrumentation Panel

It can also be used to demonstrate the concept of HVDC transmission system. It consist of

7 Modules:

 Generating Station
 3-Phase Rectifier
 DC transmission Line
 3-Phase Sinusoidal Inverter
 Transmission substation
 3-Phase load
 Instrumentation Module

The project has been made like Lab Volt trainer, but Lab Volt Trainer costs around $5000
while our project total cost is around 25000 Rs. Hence this project can be used by industry
personnel and by students to familiarize with the concept of HVDC and it is cost effective.

34

Chapter 8 Recommendations

CHAPTER EIGHT

RECOMMENDATIONS

Some of the recommendations to improve this project are:

 A data acquisition system should be integrated with this trainer to make it a
mini SCADA to acquire values like Voltage, Current, and Temperature should be
monitored continuously even from a remote area.

 The inverter in this trainer can be tweaked to become a 3-Phase Controlled
Rectifier. Which will allow the user to experiment more and it also broadens the
scope of the project.

 Instead of constantly switching wires from one line to another in the
transmission line module, simply a LCD could be interfaced with a keypad to
enter the desired distance to map on the DC transmission line.

 By the addition of Zero Crossing Detector, a tachometer, and a little
modification in the software, the Inverter Module can be used to connect Solar
Panels to Grid as well as it can be used to connect a very large Wind Turbine
coupled to a Wound Rotor Motor by feeding the rotor through a Rectifier and
Inverter by adjusting the rotor frequency such that the combined rotor frequency
and rotor speed equals the line frequency.

 By the addition of a potentiometer and a little modification in the software,
it can be used as a Variable Frequency Drive for Synchronous and Induction motor
with Feedback control System.

35

REFERENCES

 HVDC Transmission, Michael Bahrman P.E, ABB grid systems, WECC
transmission planning seminar, February 2-3, 2009
 HVDC with Voltage Source Converters – A Desirable Solution for Connecting
Renewable Energies, Ying Jiang-Häfner, Rolf Ottersten, Energynautics conference

“Large-scale integration of wind power into power systems ”, Bremen, Germany,

2009.
 Power System Interconnections Using HVDC Links, John Graham, Geir Biledt and
Jan Johansson, IX SEPOPE Conference 2004.
 HVDC Grid Feasibility Study, Study Committee B4, Cigré.

 Advantage of HVDC transmission, Gunnar Asplund, Urban Åström and Dong Wu,
Keynote Lecture, Beijing, China, August 25-28, 2005.
 J. Holtz, “Pulse width modulation for electronic power conversion, ” Proc. IEEE,
vol. 82, pp. 1194 –1214, Aug. 1994.

 O. Ogasawara, H. Akagi, and A. Nabel, “A novel PWM scheme of voltage source
inverters based on space vector theory, ” in Proc. EPE European Conf. Power
Electronics and Applications, 1989, pp. 1197 –1202.

 M. Depenbrock, “Pulsewidth control of a 3-phase inverter with nonsinusoidal
phase voltages, ” in Proc. IEEE-IAS Int. Semiconductor Power Conversion Conf.,
Orlando, FL, 1975, pp. 389 –398.
 Modern Power Electronics and AC Drives, by Bimal K. Bose. Prentice
Hall Publishers, 2001

 Power Electronics by Dr. P.S. Bimbhra. Khanna Publishers, New Delhi, 2003. 3rd
Edition.

 A Power Electronics Handbook by M.H. Rashid. Academic Press 2001.

36

 MathWorks, Inc. 1998. The student edition of Simulink: dynamic system simulation
for MATLAB: user's guide. Upper Saddle River, N.J. : Prentice Hall.

 Zhou Yuanshen, AC and DC speed control system and MATLAB simulation, China
Electric Power Press, 2011.

37

MUR1510, MUR1515,
MUR1520, MUR1540,
MUR1560

Preferred Devices
SWITCHMODE
Power Rectifiers

. . . designed for use in switching power supplies, inverters and as
free wheeling diodes, these state –of–the–art devices hav e the
following features:
Ultrafast 35 and 60 Nanosecond Recovery Time
175C Operating Junction Temperature
Popular TO –220 Package
High V oltage Capability to 600 V olts
Low Forward Drop
Low Leakage Specified @ 150C Case Temperature

http://onsemi.com

ULTRAFAST
RECTIFIERS
15 AMPERES
100–600 VOLTS

1

Current Derating Specified @ Both Case and Ambient Temperatures

Mechanical Characteristics:
Case: Epoxy, Molded
Weight: 1.9 grams (approximately)
Finish: All External Surfaces Corrosion Resistant and Terminal
Leads are Readily Solderable
Lead Temperature for Soldering Purposes: 260C Max. for
10 Seconds
Shipped 50 units per plastic tube
Marking: U1510, U1515, U1520, U1540, U1560

MAXIMUM RATINGS

Please See the T able on the Following Page
3

4

1
3

TO–220AC
CASE 221B
PLASTIC 4

MARKING DIAGRAM

U15xx

U15xx = Device Code
xx = 10, 15, 20,
40 or 60

ORDERING INFORMATION

Device Package Shipping
MUR1510 TO–220 50 Units/Rail
MUR1515 TO–220 50 Units/Rail
MUR1520 TO–220 50 Units/Rail
MUR1540 TO–220 50 Units/Rail
MUR1560 TO–220 50 Units/Rail

Preferred devices are recommended choices for future use
and best overall value.

Semiconductor Components Industries, LLC, 2000
October, 2000 – Rev. 2 Publication Order Number:
MUR1520