simulation of HVDC system.. and make reliable of HVDC.. fault clearing in monitering system

1. L.E. COLLEGE-MORBI I
L. E. College, Morbi
GUJARAT TECHNOLOGICAL UNIVERSITY
“SIMULATION AND ANALYSIS OF HVDC”
A Project Report On
SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
AWARD OF THE DEGREE OF
BACHELOR OF ENGINEERING
Electrical Engineering
SUBMITTED TO:
L. E. COLLEGE, MORBI
SUBMITTED BY:
Student Name Enrollment No.
Bhimani Vishal R. 100310109056
Patel Priyesh B. 100310109059
GUIDED BY:-
Prof. S. N. Purohit
Electrical Department
October 2013

2. L.E. COLLEGE-MORBI II
Lukhdhirji Engineering College, Morbi
Gujarat Technological University
CERTIFICATE
This is to certify that
1. Bhimani Vishal R. (100310109056)
2. Patel Priyesh B. (100310109059)
of final year Electrical Engineering students have satisfactorily and accurately completed
their project work entitled “Project on Simulation And Analysis of HVDC system” for
the subject code 170001 Project I in the 7th semester of academic year 2013-14 for the
partial fulfilment of the award of the Bachelor of Engineering in Electrical Engineering at
Gujarat Technological University.
DATE:-
PROF. S. N. PUROHIT PROF. A. K. JOSHI
PROJECT GUIDE HEAD OF DEPARTMENT

3. L.E. COLLEGE-MORBI III
ACKNOWLEDGEMENT
We owe a great many thanks to a great many people who helped and supported us during the
writing of this report. Our deepest thanks to S.N.Purohit the Guide of the project for guiding and
correcting various documents of ours with attention and care. He has taken pain to go through the
project and make necessary correction as and when needed. We express our gratitude to our head
of the Department Prof A.K.JOSHI for his invaluable support and encouragement at every stage.
We also express our thanks to the Principal Prof. P. C. Vasani , Lukhdhirji Engineering College,
Morbi-2, for his constant support and encouragement. We would also thank our Institution and the
faculty members without whom this project would have been a distant reality.
Name Sign
Bhimani Vishal R.
Patel Priyesh B.

4. L.E. COLLEGE-MORBI IV
ABSTRACT:
In HVDC system, transmission simulation causes controlling active and reactive power
flow control.
And transmission line under fault condition to located a fault part location. And solve the
fault in transmission line.
In HVDC system VSC controlling a thyrister valve temperature. Then better performance
working thyrister cooling system.
After HVDC simulation making a transmission line in steady state condition. And also
system make a steady state condition. And in HVDC system harmonics filter controlling
to monitor system.
When harmonics high that time automatic shown a signal in monitor. And HVDC system
stability making better. Controlling frequency in HVDC system.
We are controlling HVDC system use through simulation. And using a different type of
simulation software MATLAB, PSCAD. In HVDC we are take different-different
condition and making a simulation.

5. L.E. COLLEGE-MORBI V
TABLE OF CONTENTS
ABSTRACT……………………………………………………………………………….iv
TABLE OF CONTENTS…………………………………………………………………...v
LIST OF FIGURES………………………………………………………………………...vii
LIST OF TABLES………………………………………………………………………….vii
GLOSSARY OF TERMS…………………………………………………………………..viii
TABLE OF CONTENTS:
NO. NAME PAGE
NO.
1 INTRODUCTION 9
2 HVDC SYSTEM AND SIMULATION
2.1:-TYPE OF LINK
2.1.1:-MONOPILAR LINK
2.1.2:-BIPOLAR LINK
2.1.3:-HOMOPOLAR LINK
2.2:-HVDC COMPOONANT
2.2.1:- VOLTAGE-SOURCE CONVERTERS (VSC)
2.2.2:- CONVERTER TRANSFORMERS
2.2.3:- FILTER
2.2.4:-SHUNT CAPACITOR
2.2.5:- DC CABLE
2.3:-HVDC SIMULATION
2.3.1:-WHY NEED HVDC SIMULATION
11
3 SIMULATION OF HVDC TRANSMISSION LINE ON
MATLB
3.1:-DISCRIPITION OF HVDC LINK
3.2:-BLOCK DIAGRAM
3.3:-SIMULATED DYNAMIC MODEL
14

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3.4:-SIMULATION DIAGRAM
4 SIMULATION OF HARMONICS FILTER
4.1:- DESCRIPTION
4.2:- BLOCK DIAGRAM
4.3:- SIMULATION
16
5 SIMULATION OF LINE FAULT LOCATOR ON HVDC
LIGHT ELECTRODE LINE ON PSCAD
5.1:-SUMMERY
5.2:-SUMMERY OF SIMULATION
5.3:-SIMULATION DIAGRAM
5.4:-SIMULATIONS
18
6 ADVANTAGES, DISADVANTAGES AND APPLICATION
OF HVDC SIMULATION
6.1:-ADVANTAGES
6.2:-DISADVANTAGES
6.3:-APPLICATION
21
CONCLUSION
REFERENCE

7. L.E. COLLEGE-MORBI VII
LIST OF FIGURES
SR.NO FIGURE
NO.
CONTENT PAGE
NO
1 Fig.2.1 Monopolar link 11
2 Fig.2.2 Bipolar link 11
3 Fig.2.3 Homopolar link 12
4 Fig.3.1 Schematics of the dynamic model 14
5 Fig.3.2 The DC Circuit Arrangement Simulated by the
Dynamic Model
14
6 Fig.3.3 Simulation of HVDC transmission line on MATLAB 15
7 Fig.4.1 Three-phase harmonics filters 17
8 Fig.5.1 The PSCAD simulation environment 19
LIST OF TABLES
SR.NO TABLE NO. CONTENT PAGE
NO.
1. TABLE 6.1 list of simulation 20

8. L.E. COLLEGE-MORBI VIII
GLOSSARY OF TERMS
AC - Alternating Current
IGBT - Insulated Gate Bipolar Junction Transistor
VCS - Voltage source converter
HVDC - High voltage direct current
DC - Direct Current
TDR - Time domain refeltomerer
LCC - line-commutated converters

9. L.E. COLLEGE-MORBI 9
CHAPTER 1: INTRODUCTION
INTRODUCTION:
The rapid increase in electricity consumption all over the world is pushing the high-voltage
alternating-current (HVAC) grid to operate very close to its limits. In addition to that, the
Increased penetration of wind energy is presenting new challenges before the existing
HVAC grid. In this new scenario, the idea of high-voltage direct-current (HVDC) grid
is emerging to provide a backbone to the existing AC networks and to facilitate the
integration of bulk amount of power.
Due to the lower losses in DC cables, HVDC transmission has become more popular than
HVAC for long distance. The HVDC transmission can be based on either line-commutated
converters (LCCs) or voltage-source converters (VSCs). Among them, VSC-HVDC
technology is particularly suitable for DC grid formation and integration of power station
because it does not need any additional reactive-power support and does not depend on
external voltage sources for commutation.
In this project we introduced to you how work HVDC system by using MATLAB and
PSCAD. And in HVDC system we introduced to simulation of transmission line,
simulation of clearing fault, simulation of detecting harmonics waves and control,
simulation of VSC, simulation of light line fault located, etc.
Generally speaking, a DC grid can be defined as a VSC based multi-terminal HVDC grid,
where several converter terminals are connected in parallel with the DC buses. The
advantages of such a DC grid can be summarized as follows:
a) Reduction in the number of converters compared to several point-to-point HVDC
connections,
b) Improved power flow control and energy trading,
c) Reduction in the effect of intermittency for HVDC connections.
The successful operation of a VSC-HVDC link depends heavily on the control of grid-
connected VSCs. Out of different control strategies; vector-current control is most
commonly used by the industries due to its current limiting capability and efficient
decoupling of active and reactive powers. However, for a very weak network, the vector

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current control finds it difficult to produce expected results .As an alternative, a new
approach called power synchronization control has been proposed recently where, instead
of conventional PLL, the synchronization of the VSC with the grid is done through the
active power control loop. Due to this feature, the control strategy is capable of connecting
to a very weak ac system as well as island system. In this paper power synchronization
control has been applied for integrating to the three-terminal DC grid.
HVDC converter build through a thyrister bridge then cause HVDC system circuit more
complex.
HVDC system is very useful in the latest electrical world because HVDC have a great
reliability and lower losses.

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CHAPTER 2: HVDC SYSTEM AND SIMULATION
2.1:-TYPE OF LINK:
 Monopolar link
 Biopolar link
 Homopolar link
2.1.1:-MONOPOLAR LINK
A monopolar system has only one conductor with ground as return conductor, and it is
usefully of a negative polarity. It is suitable in submarine systems where sea water can be
used as a return conductor.
Fig.2.1 Monopolar link

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2.1.2:-BIPOLAR LINK
A bipolar system has a two conductor, one of positive and other of negative polarity. The
mutual or ground point is maintain at a midpotential. Each terminal of a bipoalar system
has two converter of equal voltage rating connected in series.
Fig.2.2 bipolar link
2.1.3:-HOMOPOLAR LINK
Homopolar system has two or more conductor with the same polarity. Additional
advantages is lower corona loss and radio interference due to negative polarity on the line.
Fig.2.3 homopolar link

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2.2:-HVDC COMPONANT
2.2.1:-VOLTAGE-SOURCE CONVERTERS (VSC)
Only thyrister valve are being using converter. This has increase a power handling
capacity of the devices.
2.2.2:-CONVERTER TRANSFORMERS
The transformer use in hvdc system before rectification of ac are term as converter
transformer. The contain of harmonics in a converter transformer is much higher than
conventional ac transformer.
2.2.3:-FILTER
Harmonics are generated in HVDC transmission line due to respective firing of thyrister
this are transmitted to the as network in which a dc link is embedded.
2.2.4:-SHUNT CAPACITORS (REACTIVE COMPENSATION)
Reactive volt-ampere are generated in the process of conversion, due to delay in the firing
angle of the converter station.
2.2.5:-DC CABLE
In dc transmission there is no skin effect in the conductor because there is no variation of
the current in the time for the same power handling capacity the size of the conductor
required in DC transmission is small
2.3:-WHY NEEDS HVDC SIMULATION
Increase efficiency
Increase capability
Increase stability
System work long life
Located any type of fault
Active and reactive power flow control

14. L.E. COLLEGE-MORBI 14
CHAPTER 3: SIMULATION OF HVDC
TRANSMISSION LINE ON MATLAB
3.1:-DESCRIPTION OF THE HVDC LINK
The principal characteristic of VSC-HVDC transmission is its ability to independently
control the reactive and real power flow at each of the AC systems to which it is
connected, at the Point of Common Coupling (PCC). In contrast to line-commutated
HVDC transmission, the polarity of the DC link voltage remains the same with the DC
current being reversed to change the direction of power flow.
This model shown on VSC-HVDC Transmission System Model represents a 10000
MVA, +/- 500 kV VSC-HVDC transmission link
3.2:-BLOCK DIAGRAM
Fig.3.1 schematics of the dynamic model
3.3:-SIMULATED DYNAMIC MODEL
Fig. 3.2 The DC Circuit Arrangement Simulated by the Dynamic Model

15. L.E. COLLEGE-MORBI 15
3.4:-SIMULATION BLOCK DIAGRAM
Fig.3.3 simulation of HVDC on MATLAB

16. L.E. COLLEGE-MORBI 16
CHAPTER 4: SIMULATION OF THREE-PHASE
HARMONIC FILTERS
4.1:-DESCRIPTION
In HVDC installations, AC harmonic shunt filters are used to:
1) reduce harmonic voltages and currents in the power system,
2) supply the reactive power consumed by the converter. To illustrate these concepts,a 1000-MW
(500 kV, 2kA) HVDC rectifier is simulated.
The HVDC rectifier is built up from two 6-pulse thyristor bridges connected in series. The
converter is connected to the system with a 1200-MVA Three-Phase transformer (three
windings). A 1000-MW resistive load is connected to the DC side through a 0.5 H smoothing
reactor. The filters set is made of the following four components of the powerlib/Elements library:
- one capacitor banks (C1) of 150 Mvar modeled by a "Three-Phase Series RLC Load",
- three filters modeled using the "Three-Phase Harmonic Filter"
(1) One C-type high-pass filter tuned to the 3rd (F1) of 150 Mvar
(2) one double-tuned filter 11/13 th (F2) of 150 Mvar
(3) one high-pass filter tuned to the 24th (F3) of 150 Mvar
The total Mvar rating of the filters set is then 600 Mvar. A three-phase circuit breaker (Brk1) is
used to connect the filters set on the AC bus.

17. L.E. COLLEGE-MORBI 17
4.2:-BLOCK DIAGRAM:
Fig.4.1 three-phase harmonics filters

18. L.E. COLLEGE-MORBI 18
CHAPTER 5: SIMULATION OF LINE FAULT
LOCATOR ON HVDC LIGHT ELECTRODE LINE
ON PSCAD:
5.1:-SUMMERY
In this bachelor thesis, cable fault locators are studied for use on the overhead electrode
lines in the HVDC (High Voltage Direct Current) Light project Caprivi Link. The cable
fault locators studied operates with the principle of travelling waves, where a pulse is sent
in the tested conductor. The time difference is measured from the injection moment to the
reflection is received. If the propagation speed of the pulse is known the distance to the
fault can be calculated. This type of unit is typically referred to as a TDR (Time Domain
Reflectometer). The study is performed as a computer simulation where a simplified
model of a TDR unit is created and applied to an electrode line model by using
PSCAD/EMTDC. Staged faults of open circuit and ground fault types are placed at three
distances on the electrode line model, different parameters of the TDR units such as pulse
width and pulse amplitude along with its connection to the electrode line are then studied
and evaluated.
The results of the simulations show that it is possible to detect faults of both open circuit
and ground fault types with a suitable TDR unit. Ground faults with high resistance
occurring at long distances can be hard to detect due to low reflection amplitudes from
the injections. This problem can somewhat be resolved with a function that lets the user
compare an old trace of a “healthy” line with the new trace. The study shows that most of
the faults can be detected and a distance to the fault can be calculated within an accuracy
of ± 250 m.
The pulse width of the TDR needs to be at least 10 μs, preferable 20 μs to deliver high
enough energy to the fault to create a detectable reflection. The pulse amplitude seems to
be of less significance in this simulation, although higher pulse amplitude is likely to be
more suitable in a real measurement due to the higher energy delivered to the fault. The
Hypotonic TDR 1150 is a unit that fulfil these requirements and should therefore be able
to work as a line fault locator on the electrode line.

19. L.E. COLLEGE-MORBI 19
5.2:-SUMMERY OF SIMULATION
A fault on the pole line can be detected on-line by detecting the incoming travelling
waves in each station, by comparing the arrival time of waves in the two stations the
location can be determined. However, as the voltage on the electrode lines is
approximately zero or very low, this method is not applicable.
The aim of this study is to find equipment that can detect the location of the fault along
the electrode line.
It can be off-line equipment, i.e. does not need to locate the fault when the link is in
operation. The fault locator will inject a pulse into the line and detect the time when the
reflected pulse comes back.
The simulations should answer a number of issues which affect the ability to locate a
fault. How different types of faults, distances to faults, pulse amplitude, pulse width affect
the ability to locate a fault. The simulation should also elucidate the existence of any
interference from parallel lines.
5.3:-SIMULATION DIAGRAM
Fig.5.1 The PSCAD simulation environment

20. L.E. COLLEGE-MORBI 20
5.4:-SIMULATIONS
Table 1 shows a list of the simulations. The simulations are done by changing one
parameter at a time to be able to study changes.
Table 5.1, list of simulation
No. Item Issue Simulations
1 Fault type High resistance faults may be
hard to detect.
Is the amplitude of the
reflection big enough to detect?
2 Distance to fault How does the distance from the
measuring point to the fault
affect the result?
3 Pulse width How do different pulse widths
affect the result?
4 Pulse amplitude How do different pulse
amplitudes affect the result?
5 Connection How does the connection of the
TDR to the line affect the
result?
6 Parallel line How does a parallel line in
operation affect the result?
7 Electrode station
Configuration
How does the connection of the
line to the electrode affect the
result?
8
Arc reflection
Does a high voltage pulse
increase the performance of the
TDR?

21. L.E. COLLEGE-MORBI 21
CHAPTER 6: ADVANTAGES, DISADVANTAGES
AND APPLICATION
6.1:-ADVANTAGES
System stability.
Lesser corona loss and radio interference.
Greater reliability.
Bulk power long distance transmission.
Tower size and cost.
Control harmonics.
Independent control of active and reactive power
Capability to perform the AC voltage or reactive power flow control at points of
interconnection to the power system
No need for heavy reactive power compensation
Significantly smaller footprint
Reliable operation with a weak or even passive system, including black start
6.2:-DISADVANTAGES
Cost of converting station.
Reactive power requirement.
Less overload capacity.
Loss in cooling system.
Absence of suitable circuit breakers

22. L.E. COLLEGE-MORBI 22
6.3:-APPLICATION
Power station work reliable
System gives dynamic controlling
System controlling as a monitoring system

23. L.E. COLLEGE-MORBI 23
CONCLUSIONS:
We can control the HVDC active and reactive power Controlling the harmonics and give
protection of HVDC system. And simulation of HVDC transmission line located any
type of fault. Also controlling frequency and other dynamics characteristics HVDC
simulation software are MATLAB, PSCAD.

24. L.E. COLLEGE-MORBI 24
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