Fault Identification in DFIG Wind Turbines

The provided text comprises a list of academic publications related to fault analysis and stability assessment in Doubly Fed Induction Generator (DFIG)-based wind turbine systems. The papers delve into various aspects, including fault identification methods (FFT, Neural Networks), grid integration challenges, transient stability impact, voltage stability analysis, and the influence of intermittent wind generation on power system stability. The focus is on understanding how DFIG wind turbines interact with power grids under both normal and faulty conditions.

Short circuit calculations in networks with large
penetration of distributed generation
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Table of Contents
Table of Contents...........................................................................................................................1
1. Introduction.........................................................................................................................1
2. Literature review................................................................................................................2
3. Aim and Objective..............................................................................................................8
4. Methodology......................................................................................................................14
4.1 Grid Component Model...............................................................................................15
4.2 Modelling of Wind turbine..........................................................................................16
4.3 Variable Speed Wind Turbine.....................................................................................17
4.4 Variable speed DFIG wind turbine.............................................................................17
4.5 Variable speed wind turbine with synchronizer generator..........................................19
4.6 Variable speed DFIG wind turbines- fault analysis....................................................21
4.7 DFIG protection system during grid faults..................................................................24
4.8 Fixed speed wind turbine............................................................................................25
5. Expected Outcome............................................................................................................30
6. Work Plan..........................................................................................................................51
7. Conclusion.........................................................................................................................53
8. Bibliography......................................................................................................................55
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List of Figures
Figure 1 Horizontal axis wind turbine...........................................................................................12
Figure 2 Co-axial, multi-rotor horizontal axis...............................................................................13
Figure 3 Vertical axis wind turbine...............................................................................................14
Figure 4 Giromill wind turbine......................................................................................................15
Figure 5 Onshore...........................................................................................................................15
Figure 6 Offshore...........................................................................................................................16
Figure 7 Grid Component Model..................................................................................................18
Figure 8 Configuration..................................................................................................................25
Figure 9 Gain scheduling control..................................................................................................26
Figure 10 SVC control...................................................................................................................29
Figure 11 Gantt chart.....................................................................................................................51
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1. Introduction
The Electric power will be generated from the renewable energy, an example of which is
wind energy. The DigSilient software will simulate the power system. Electric Power Systems is
a complicated and complex structure. The electricity grid will be inserted into the whole
structure. At current situation, the requirement for the electric power is increased in the world.
For providing the power with low Carbon Emissions, this renewable energy is utilized. Electric
Power System comprises of many functions like the evaluation of the flow of load flow,
evaluation of the short path and fault, earthlings revisions, switchover voltages and insulation
organization. It is normally utilized for the production of the electrical energy. The power system
creates efficient and low-cost electricity. It has the components for the distribution and
transmission of electricity to the consumers. This power system has some of the major
components like transformers, power stations, alternators, circuit breakers, bus bars and auxiliary
devices. Nowadays, the power is generated by utilizing renewable energy like sunlight, wind,
tides, rain, waves and various type of biomass. This renewable energy helps in the reduction of
the carbon segregations, purification of the air, protection of the health of human from the
pollution and saving the functions of earth. Being inexhaustible in nature, the energy is produced
from the natural resources and is never depleted. It can also be used instead of fossil fuels and
thus can be termed as eco friendly in nature. Power generation is done by one of the important
renewable energy, wind. Apart from being eco friendly, wind energy is inexpensive and follows
a simple procedure for power generation. Moreover, this energy is also utilized for all types of
practical uses like charging batteries, pushing water and crushing grain. The kinetic energy from
the wind is utilized for the generation of mechanical power, which also provides benefits to both
economy and environment. Power analysis is performed by utilizing inexpensive software
known as Dig SILENT. The main functions of this software include handling of data, better
improved workflow and modeling capabilities. Moreover, it also helps in the reduction of the
execution cost of project and training requirement. The operating process of Dig SILENT is
extremely easy. It is also used in high-end applications like circulated generation, wind power
and handling process of large Power Systems. The electricity grid acts as a mediator network for
delivering electricity from producers to the consumers. For the production of electrical power
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generator stations are present. The High Voltage Transmission Lines are utilized for carrying the
power from the reserved sources to the requested centers. The combination of minor wind
systems does not make any major operational complications, which regularly maintains the
energy and reliability of supply network. When the large combination of the wind system is
pointed at the network the critical operational complications is created. When one connects many
wind farmhouses into similar substation, the created topology will be more critical and complex.
For the reduction of this problem, the analysis will be made on the troubles. The disturbances
that are created at the large wind farm will be short circuits and wind gusts.
2. Literature review
According to the author (Amora and Bezerra, 2017), VSCF i.e. DFIG speed idle frequency
wind power transmission system is modeled. It involves wind wheel dynamic, generator
dynamic, wind variation, power system and drive train. The DFIG wind power system design
parameters simulate the entire system. For simulating the entire system, mat lab Simulink tools
are used. The DFIG wind power system design parameters are simulated by the prototype FD61-
1000. In power system, the variable speed idle frequency, the functional feature is revealed.
Under the wind variation condition, the influence of another load is also revealed. The
integration of wind energy into the grid is the major aspect of power generation of wind. The
undesired fluctuation of power into the grid is produced by wind resource. It is produced during
the utilization of fixed speed wind turbine. The stall wind turbine is extremely popular. We have
used two types of wind turbines. The two types of VSCF namely direct drive gearless permanent
magnetic generation system and generator system. Because of the low cost of the control system,
the former machine is famous. Enhancement of power capacity is the advantage in the offshore
wind park. The rotor blade drives the wounded rotor asynchronous machine via the gearbox.
Through the pad mount transformer and main circuit contractor, generator stator winding
connects to the grid. For regulating the output power, it provides excitation to rotor winding.
Based on IGBT, the regulation of output power is done by utilizing Pulse Width Modulation
Converter. In the overrated field of output power, hydraulic unit driven pitch system behaves like
a power limiter. Lastly, under the wind variation condition, we got the output for speed idle
frequency wind turbines impacts on the power system as well as load.
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According to the author (Chen, 2017), the development of wind power industry is increased.
This is increased because many wind farms are linked into the power system. Some of the
challenges of this system include system control and operation, power quality, and system
stability. The wind farm combination into the power system introduces these significant
challenges. The modern power system of wind proposes the wind turbine requirements.
The author (Boutsika, Stavros, and Papathanassiou, 2017) states that, for the distributed
generation interconnection, consideration of fault level might be an inhibiting factor especially at
the medium level of voltage. For the calculation of the fault level result, IEC 60909 latest edition
standard is applied. This standard is applied to distributed generation in the network of low and
medium voltage level distribution. For the case studies of distributed generation, IEC calculation
methods normally involve entire related equations. The fault of grid contribution of several
distributed generation types is discussed. It involves the entire relative types of distributed
generation sources. For the reduction in the level of fault, the potential measure is included. The
system has some leading features for short circuit current. The emphasis is fixed on upstream
system contribution. The networks for distribution are featured by short circuit capacity design.
We are used desirable peak fault current relates to switchgear, construction and the equipment
mechanical and thermal withstand capacity. The net level of fault is calculated by blended short
circuit contribution of distributed generation and upstream grid. For the newly distributed
generation installation interconnection, the control is usually the most preventing factor. The
voltage transformer short circuit impedance calculates the upstream grid fault current
contribution and the determination of the low voltage and medium voltage radial network. For
improving the network overall power quality performance and voltage regulation, low voltage
should be selected. Therefore, the existing distribution network short circuit capacity is close to
design value. For the protection and coordination of switchgear, the short circuit calculations are
performed. The performance is based on the establishment of international and national
practices. The accepted standards are ANSI or IEEE and IEC. In this paper, we have applied
60909 IEC standard. This standard encompasses the configurations, several network voltage
levels, load equipment and functioning conditions. Although it focuses on conventional power,
system paradigm has large centralized traditional generators. No specific guidelines are provided
on fault contribution of medium and small size distributed generation installation. The twofold
one is the main objective. It gives concise and easy output. It is utilized for evaluating the fault
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level in low voltage and medium voltage radial distribution network and the point where the
distributed generator is connected. This even includes recommendations, which are used for the
purpose of fault current input for the several kinds of distributed generations.
The author (Afifi et al., 2017) states that in the network of distribution, the generation has
varied conventional short circuit capacity and downstream power flow concept. The distribution
generation can be connected even without implications. There are various disadvantages of this
distributed generation connection like the enhancement of voltage profile, overreaching network
short circuit level. It might restrict the link to the grid. Evaluation of the network is done on the
basis of IEEE thirteen bus test system by software called ETAP. The unbalanced and balanced
faults are included.
The author (Bazilian, Denny and O’Malley, 2017) tells that due to its relative isolation, the
dependency of fuel import, size, and infrastructure of the grid, Ireland facing the critical period
in the form of robust RE policy. The colloquium title on the technical challenge of enhancing
wind energy dispersion is followed. It encompassed discussion on the studies of the requirements
of grid, wind penetration and wind farm design and modeling. The electricity system present
state the status of electricity market and imposes into the view of the technical problems that are
required to be solved for the enhancement of the wind penetration.
According to the author (El-Zonkoly, 2017) in distribution power system, the distributed
generation penetration could affect the characteristics and the conventional fault current level.
The conventional arrangements for protection, which is developed in the distribution utilities, are
complex. The reclosing procedure could be influenced. In the distribution system, reclosing
scheme and the protection coordination based on data exchange and communication and
automation technology could be realized with rapid developments. In the power distribution
networks, for fault diagnosis, the multi-agent on the basis of the scheme has given. The
distribution network is provided by various sections. Relay agents measure the bus current. It can
classify and detect the faults. It even determines the location of the faults. The wavelet
coefficients entropy techniques are used. The proposed protection producer’s performance is
tested via simulations. There are two systems. One is practice sixty-six-kilo volt system and the
other one is benchmark MV distribution system.
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According to the author (Das and Santoso, 2017), the wind speed variation effected by the
wind turbine is investigated. The wind turbine provides fault current, which is six times higher
the limited current. The speed of the wind variation impacts the generator internal voltage. When
the inner voltage of the generator is high, fault current becomes high while the fault happens.
When the internal voltage is low, the corresponding short-circuit current is also low. The main
objective is to investigate the importance of the fault current variation in corresponding to the
security device setting. It is even calculated from the standard IEC60909.We conducted 5
comprehensive studies. The minimum and the maximum fault current are determined by 60909
IEC standards for each of the case studies. At various wind speeds, it is compared with the
simulation output.
According to the author (Safigianni, Koutroumpezis, and Spyridopoulos, 2017), in large-
scale MV power distribution networks, the DG penetration results are examined. The 3 power
substations feed 21 lines. From the photovoltaic units, the injected power came. According to the
national and international standards, DG influence on network branch I (current), V (voltage)
profile, losses and in feeding substations short circuit range at MV bus bar, is examined. We
proposed the technical solutions. We explored arising issues. This is related to the application for
the pilot. The conclusion concerned about extended DG penetration is set out in real power
network distribution.
According to the author (Muljadi et al., 2017), WPP consisting of many turbines, which is
interconnected through the underground cable. Each turbine is linked to the transformer, which
increases the generating voltage and has the range of 690 V to MV. In wind power plant, under
fault conditions, the effect of current on transmission network is evaluated. It is an extremely
challenging task to protect the engineers because of the differences in topology. These topology
differences are in between the typical generating units and wind turbine generators. For various
types of fault conditions, the wind power plant behavior is investigated. It also investigates
configuration of the transformer, relative compensation capacitor, and the impact of wind turbine
type. We discovered the response of voltage at the various buses. Along with the symmetrical
components, the short-circuit line I (current) is proposed.
The author (Chen, 2017) states that the rapid development of wind power industry many
wind farms IS are combined together with the power systems. Few challenges are presented
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because of the wind farm combination with the power system. The challenges are listed as power
quality, the stability of system and system control and operation. The modern wind power device
is described. The wind turbine connection requirements and control methods for meeting the
specifications are discussed below.
The author (Amora and Bezerra, 2017) states that the attained transient stability results while
computing wind farm connection effects in the power system. The software is developed for the
stability simulation in MATLAB, which is a user friendly interface. It permits to execute in
various cases such as conventional generation loss, SC in the network, function under wind gust,
load reduction, operation under turbulent wind and sudden wind farm disconnection. The
simulation results used to evaluate stability effects of wind farm integration, test power system
into the electric grid.
The author (Potamianakis and Vournas, 2017) states that the methodology for the
simplification of the distribution network is presented. This methodology consists of a number of
wind farms provided with medium voltage lines and induction generators. The methodology is
created for the indefinite equivalent network. It even consists of equivalent medium voltage
feeder and equivalent wind farm. The analyzed power system complexity is reduced by the
methodology, which is proposed. It leads to accelerating simulation time and permitting several
applications. The applications are listed with limited resources, stability analysis, and security
assessment. Through its application, methodology validation is determined by karystos
distribution network in Evia Island and entire network of Evia Island. We simulated the response
as well as minimized the network under same contingency. We compared the results of
simulation. By utilizing MATLAB or Simulink, the performance of the simulation is checked. In
NTUA, the software package is developed. It is suitable for stability analysis and simulation of
the small-interconnected power system.
According to the author (Afifi et al., 2017), in distribution networks, DG penetration has
changed the conventional concept of SC capacity and downstream power flow. Without
implications, DG can be connected in some instant. Connection of DG even has some of the
major disadvantages. The main disadvantages include exceeding SC level in network and voltage
profile enhancement. It even restricts the DG connection to the network. The DFIG wind
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turbines impact on IEEE thirteen bus distribution test system SC level by the software is known
as ETAP. It involves unbalance and balance faults.
The author (Gohil, Mehta and Vora, 2017) states that, in power system, the SC current
calculation of the equipment is most significant. The calculation of SC current is for suitable
relay features selection and CB for system protection. The power system is changed because of
RE source large-scale penetration on the conventional system,. The solar and the wind energy
sources are the RE sources that are involved in the turbine. The various types of generator supply
the wind energy. When compared to the conventional synchronous generator, the DFIG is the
common type generator that provides different behavior. The DFIG SC current contribution is
determined analytically. It is validated by EMTDC or PSCAD software under different wind
speed. It is even validated concerning distinct output of the generator voltage drop.
The author (Margossian and Sachau, 2017) states that SC programs with typical calculation
are not considered as the general behavior of inverter based on DG. With the combination of the
techniques, various tools are to be developed. The technique that is used accommodates inverter,
which is based on distributed generator having various fault response and standard SC
calculation tools. By using model named realistic test distribution network, the technique is
compared with other techniques and evaluated.
According to the author (Kazachkov, Feltes and Zavadil, 2017), the wind energy conversion
system includes electrical and mechanical equipment as well as their control. For the simulation
of power system stability, the system modeling needs the cautious examination of equipment. It
also requires control to evaluate the characteristics which his significant in bandwidth and
timeframe. The characteristics are most significant for the design of wind or turbine farm. For
simulation package for stability and for effective PS load flow. The electrical, air-dynamical and
mechanical factors are modeled. Dynamic models with their control represent the various types
of variable speed and constant speed technologies. The load flow model permits the wind farm
aggregation consisting of 10-100's of the wind turbine unit.
According to the author (Huda and Živanović, 2017), in recent years, the DG integration into
distribution network has obtained in terms of efficiency and reliability improvement. Various
technical problems might occur because of the enhancing distributed generation penetration.
These challenges include power quality, protection problems, and voltage control. In order to
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examine the distributed generation impacts on the distribution system, extra components required
to model with the typical component of the distribution system. The aim is to analysis distributed
system impacts on system function, challenges mitigation; system components needed model,
associated regulation and standard for distributed systems successful function. The number of
open source and typical tools is presented for distribution systems analysis and model. For
analyzing the enhanced distribution generation penetration impacts, the conceptual
computational tool is involved.
3. Aim and Objective
To generate the electrical power at the wind farm, the wind is used as a source. The wind is
supplied to the electrical generator to generate the higher voltage. The electrical generators used
at the wind farm are to be induction generators. Wind is used instead of the diesel engine, to
produce the higher voltage. The transformer helps in improving the wind farm voltage. The
transmission and distribution voltage depends on the interconnection type. The voltage produced
at the wind farm depends on the wind speed. Due to the high speed of the wind, the higher
voltage is created. Sometimes the high wind short-circuits the network. It creates the much
amount of heat and mechanical damage to human beings. The short circuit is also occurred by
increasing current in the system. It provides damage to the system. The short circuit is present in
the form arc. It breaks the conductor for a long time. Many types of fault occurred due to the
short-circuiting. The fault creates the variety of responses for the wind turbine types. The fault
occurred at wind turbine due to the short-circuiting. The faults are to be the 3LG fault, SLG fault,
and LL and LLG faults.
Wind Turbines
Wind turbines ride on a pinnacle to get energy from the breeze. The higher the edges are, the
more they can exploit speedier and less turbulent breeze. The breeze turbine includes 3 portions.
They are sharp edges, shaft, and generator:
1) Blades: It drives boundaries to a breeze. When the breeze powers cutting edge to move, a part
of breeze vitality is exchanged to the rotor in that portion.
2) Shaft: The pole is additionally twisted during rotor turns and exchanges the mechanical energy
into rotational energy.
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3) Generator: It utilizes the difference in electrical charge to provide alteration in voltage. The
voltage leads the electric current by the cables for appropriation. The Horizontal axis is one
type of wind turbines. It is commonly used one. The blades, generator, and shaft are placed at
the top of the tower. Blades face the wind. The shaft is placed to be horizontal to the ground.
Advantages
1) It provides the stability to the system because the blades are placed in the center of gravity at
the turbines side (Tsai, Lin, and Tseng, 2017).
2) It has the Skill to arm warp that provides the blades to take the best angle of attack
3) Tall pinnacle allows access to grounded breeze with wind shear
4) Tall pinnacle permits situation on uneven land or in seaward areas
5) Can be sited in woods above tree-line
6) Most are self-beginning
Disadvantages
1) Trouble operating in nearby ground breezes
2) Problematic to carriage (20% of equipment costs)
3) Problematic to fix (require tall cranes and skilled operators)
4) Effect sensor on nearness
5) Local obstruction to aesthetics
6) Problematic in maintenance
The impact of creating electric power at the wind turbine are Emissions Reduction,
Electricity Amount and Energy balances are perfect, It provides security and reliability of
supply, It requires high power, The mixing of fuel is affected, It provides the effect on the
electricity market. It affects the Inter-TSOs electricity trading due to excess of wind power (Pillai
et al., 2017). Totally three types of wind turbines are present there. The horizontal axis turbine is
commonly used one. The components of that turbine are pitch, shaft, gearbox, generator,
controller, Anemometer, nacelle, wind vane, high-speed shaft, tower, blades, yaw motor, Yaw
drive, Brake, Rotor (Zheng and Kezunovic, 2017).
Types of wind farm
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Wind turbines are mainly classified into three types as following
1. Horizontal axis
• Co-axial, multi-rotor horizontal axis
• Counter-rotating axis turbine
2. Vertical axis
• Darrius turbine
• Giromill turbine
3. Location
• Onshore
• Offshore
Horizontal axis wind turbine
HAWT has the electrical generator at the top of the tower and main rotor shaft. Wind sensor
coupled with a servo motor is generally utilized in the large wind turbine, while simple wind
vanes are utilized in the small wind turbine. The gearbox is used for change of slow rotation into
a quick rotation for driving an electrical generator (Cai, Erlich and Fortmann, 2017).
Figure 1 Horizontal axis wind turbine
Co-axial, multi-rotor horizontal axis
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More power is producing in the co-axial, multi-rotor wind turbines while compared to the
same diameter of the single rotor (Subbu Lakshmi, 2017). Coaxial multi-turbine windmills are
more useful in the area of predominantly unidirectional wind resource. Critical speed can be
raised by placing the driver shaft under tension and the number of intermediate support is
reduced.
Figure 2 Co-axial, multi-rotor horizontal axis
Horizontal axis turbine in rotation
It is used in the concept of a tidal turbine. Blade element momentum theory (BEMT) is used
to design the original blade profile (Hossain et al., 2017).
Vertical axis wind turbine
Vertical axis wind turbine is used for catching the wind from all direction. VAWT do not
need rudders, yaw mechanism and downwind coming. Their generator is placed close to the
ground; hence it is easy to access. A disadvantage of the vertical axis wind turbine is some
designs are not self-starting (Wang et al., 2017) (Vittal et al., 2017).
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Figure 3 Vertical axis wind turbine
Darrius wind turbine
It is the turbine that contains a number of airfoils, which are vertically attached to a
framework or rotating shaft. The Darrius type uses curved or straight bladed rotor blades are
used. And the rotating axes are perpendicular to the wind stream (Liu et al., 2017).
Giromill wind turbine
In the Giromill wind turbine, two or three vertical airfoils mounted on a central mast by
horizontal supports. In Giromill wind turbine is cheaper and easier to build. In turbulent wind
condition, Giromill can work well (Anaya-Lara et al., 2017).
Figure 4 Giromill wind turbine
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Location
The land where the windmills are located.
Onshore
Turbines which located on land refers the onshore type
Figure 5 Onshore
Offshore
Wind farms that are constructed at the sea are known as offshore wind turbine (Heising and
Remler, 2017). When comparing tool and land higher wind speeds are available in offshore. This
type wind farm includes inshore water area such as sheltered coastal area and lakes (Zhang and
Yuan, 2017).
Figure 6 Offshore
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4. Methodology
In our day-to-day life, the increase in the capacity of Wind Turbine becomes the most
challenging concept in controlling method. The simulation is used to study the load flow, voltage
regulation, the transient and dynamic behavior of the model. Nowadays the tools have been
modeled to extensively utilize advanced power applications. Dig SILENT is such a tool that
could be used for Wind power applications (Sharma, Bhargava and Gajrani, 2017).
Dig SILENT is used in simulating the flow of the load, RMS fluctuations and the transient
event in software surroundings. It gives various level models and fuses the transient simulations
of instant values with the models of electromechanical simulations of RMS values (Kazachkov
and Stapleton, 2017) (Dolan, 2017). This is the most useful tool for the study of grid fault and
power quality. Dig SILENT has set measures and patterns in control framework displaying,
examination and recreation for over 24 years (Morel, Obara, and Morizane, 2017). The
demonstrated favorable circumstances of the Power Factory programming are its general
practical mix, its pertinence to the displaying of age, transmission-, dissemination and modern
lattices, and the examination of these networks' communications. With the rendition Power
Factory 2017, Dig SILENT presents a further advance towards the consistent combination of
usefulness and information administration inside a multi-client condition (Tung Linh and
Chuong, 2017). Dig SILENT Power Factory is the most prudent arrangement, as information
taking care of, displaying capacities and general usefulness supplant an arrangement of other
programming frameworks, in this way limiting task execution expenses and preparing
prerequisites (Kalyan Kumar, 2017). The across the board Power Factory arrangement advances
very streamlined work process (Honrubia-Escribano et al., 2017). Dig SILENT Power Factory is
difficult to utilize and provides food for all standard power framework investigation needs,
incorporating top of the line applications in new advances, for example, wind control and
dispersed age and the treatment of expensive power frameworks. Notwithstanding the solitary
arrangement, the Power Factory motor can be easily incorporated into GIS, DMS and EMS
supporting open framework measures (Poller, Achilles and Moodley, 2017).
Power Factory Highlights
1) Sparing across the board arrangement with wide scope of cutting-edge control framework
applications
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2) Broad and adaptable displaying capacities with rich suite of influence gear models and
libraries
3) Backings all system portrayals and stage advancements, that is any sort of outspread or
coincided 1-, 2-, 3-and 4-wire AC and DC systems (Guan-yang et al., 2017).
4) Capable system charts and realistic/perception highlights
5) Single-and multi-client condition with full help of team working, client bookkeeping, profiles
and adaptable customization
6) Exceptional information administration idea including venture forming and filing
components, ace/determined ideas to analyze and consolidate instruments
7) Boundless opportunities for process improvement in light of coordinated scripting usefulness
8) Rich interfacing and framework mix alternatives for instant EMS, GIS, SCADA, etc.
9) Proficient help through client entry or hotline, and additionally nonstop item support and
improvement.
Dig SILENT power factor Calculations
1. High voltage grids and low voltage grids
2. Between the grids, the interaction occurs
3. Short circuit analysis
4. Transients
5. Grid impedance
6. Load flow analysis
7. Harmonics
8. Switching ripple
9. Inter harmonics
10. Switching
4.1 Grid Component Model
The component model is created in the graphical programming environment. They are
basically a in built model with standard input values (Boutsika and Papathanassiou, 2017). The
components are dragged and dropped as shown in the figure.
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In Dig SILENT all the in built models of electrical components standard exist. The internal
details of the wind turbine models are used as predefined inputs and outputs as black boxes as
they can't be used directly. For grid components, different models are used at the time of
implementation of the wind turbine in the Dig SILENT(Mishra et al., 2017). The grid is modeled
under a graphics-programming environment (Odgaard and Stoustrup, 2017). To define the
parameters different equivalent circuits are used to indicate the induction generator model in the
Dig SILENT (Williams and Karlson, 2017). The electrical machinery includes the following
models
1. Squirrel cage induction generator model
2. Synchronous generator
3. DFIG model
The squirrel cage rotor is of three types
1. Double cage rotor
2. Squirrel cage rotor without current displacement
3. Squirrel cage rotor with current displacement
The inputs can be entered directly by specifying the reactance or along with the specific
resistances (Müfit et al., 2017).
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Figure 7 Grid Component Model

4.2 Modeling of Wind turbine
These models are basically of two types. They are the Variable Speed Wind Turbines and
Fixed Speed Wind Turbines. In the recent trends, the variable speed wind turbine is most widely
used model (Gohil, Mehta and Vora, 2017).
4.3 Variable Speed Wind Turbine
The Variable wind turbine has a most complicated electrical system compared to the other
type. They are usually embedded in the generator and a power converter (Cossent, Go´mez and
Frı´as, 2017).
4.4 Variable speed DFIG wind turbine
Here, the response is given to the variable speed DFIG wind turbine in order to get the
control strategies and performance calculations. The initial stage of this paper related to the
doubly fed induction generator. After that, the whole variable speed of the wind turbine can be
explained. In motivation to control strategies in various types of control levels (Chen, 2017).
The important terms of DFIG are the power handled by power converter is simply the portion
of entire wind turbine power. Along with that, the cost, loss, and size are very tiny when related
to the full-scale power converter. That can be used in full variable speed concept.
The characteristics of the DFIG configuration have a wound rotor induction generator. Along
with stator windings. That can be directly linked to the three-phase grid. Along with that, the
rotor winding can be linked to the continuous incomplete scale power converter. The continuous
converter is bi-directional power converter. That has the autonomously controlled voltage basis
converter. That can be linked to the bus. The rotor side converter and the grid side converter rule
the character of the generator. That has the ability to control in usual and fault situation. Here the
rotor voltage can be controlled by converter magnitude and phase angle for the active and
reactive power control (Eping et al., 2017).
Due to the decrease in optimal voltage in the rotor is normally lower than the optimal voltage
in the stator. The system grid can be linked to the transformer. That has two secondary they are
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1. Winding that can be linked to the stator
2. Winding that can be linked to the rotor
Here the DFIG device can permit the flexible speed that can be in the limited range. The
range of the speed can be controlled is given be the certain limit that is - 31% to + 31%. The
ranking of the converter is less than 35%. The generator power is not linked to the size of the
converter. But it can be the choice the range of the speed and the slip power. When it permits the
dynamic speed range increased about the synchronous speed increases, the charge of the power
converter can be increased.
When the speed can be limited to the certain range, the slip-induced voltage is simply the
portion of the grid voltage. That can depend on the turn ratio. The voltage of the dc bus can be
quite little (Azmy and Erlich, 2017) (Muljadi et al., 2017) (Bazilian, Denny and O’Malley,
2017). The process in the lower dc bus is performed due to the decrease in voltage rotor that can
be gathered by the three winding transform.
The DFIG has the ability to perform in sub synchronous generator and over the synchronous
generator. The power converter has the ability to perform power stream and that is why the
continuous bi-directional converter can be used in it (Cossent, Go´mez and Frı´as, 2017).
Figure 8 Variable speed DFIG wind turbine
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Here,
nsyn – synchronous speed in rpm
ngen – generator speed in rpm
It is the symbol of electrical torque in the DFIG machine. It is autonomous of the slip.
That can be used to direct the machine is working in motor or generator (Amora and Bezerra,
2017). Let us consider that entire loss in can be neglected from the stator and the rotor circuit.
The power over the rotor is termed as the slip power. That is defined as slip s. which is
multiplied by the stator power Pstator. In addition, the delivered stator power can be given
grounded on the grid power Pgrid or on the mechanical power:
Here,
ngen – generator efficiency
Compared to the squirrel cage induction machine the power converter permits DFIG more
multipurpose and bendable process (Potamianakis and Vournas, 2017). The alteration among the
various frequencies by vaccinating a rotor current that can be with flexible frequency in order to
power converter recompenses for to the shaft speed. The power converter supplies through
collector ring. That supplies the rotor winding with changing voltage with flexible magnitude
and frequency. That can be used for improving the manageable capabilities
1. It gives the DFG the capability to responsive the power control.
2. It has the capability to magnetize the DFIG over the rotor circuit, autonomously of
the grid voltage.
3. The power control and reactive power control are combined.
4. Autonomous control of the rotor excitation current (Gohil, Mehta and Vora, 2017).
4.5 Variable speed wind turbine with synchronizer generator
This deals with the variable speed of the wind turbine with the synchronous generator and its
control when normal operation and during grid faults are studied. Generally, wind turbines
19

operate at high speed and it needs a gearbox. Since, this gearbox is high in cost and produces
noise when utilized the gearless is preferred nowadays. Therefore, direct driven wind system is
utilized. The rotors and the generators will be used directly in the directly driven wind turbine
system. For the purpose of the effective efficiency and decreased weight reduction of the
components of the wind turbine, the directly driven turbine is used (Jeevajothi, 2017).
Normally asynchronous generators having many poles and each pole pitch which is small in
size has very less magnetizing reactivity. Therefore, the multi-pole asynchronous needs higher
magnetic reactance than these asynchronous generators. Since the multi-pole asynchronous
generator has larger reactivity, it is preferred for the wind turbines. These multi-pole generators
are excited electrically with the use of permanent magnets (Milano, 2017). These permanent
magnets are most suitable for the low-speed wind turbine because of the presence of many pole
numbers. Not only the poll numbers are higher, the efficiency and the excitation of DC are less.
So the multi-pole permanent magnets are utilized for the wind turbine operation (Shi et al.,
2017).
Multi-pole generators are divided into two factors. They are fixed speed, linked directly to
grid of AC and variable speed, and linked to the grid of the AC through the frequency converter.
Fixed speed generators are used often in the applications of the hydropower. These generators
are linked straight to grid and have terminal voltage with the electrical frequency. The variable
speed generators are more concentrated because of vast usage in the wind farms. This has a
characteristic of more efficient and low in cost. This generator when used with the wind farms, is
controlled by the electronic equipment. The electrical frequency of generator and power system
are separated since the generator is grid connected through the frequency inverter (Feynman,
2017). These are the normal operations of the variable speed generator used with the wind
turbine.
20

Figure 9 Variable speed wind turbine with synchronizer generator
4.6 Variable speed DFIG wind turbines- fault analysis
Wind turbines are not used in assisting the power system in case of the grid disturbance, for
the grid codes. Wind turbines are used to be disconnected from the grid, if any unusual grid is
noticed. Due to increase in the wind power capacity in power system, an abrupt change in the
power loss in the grid faults is created due to the wind turbines disconnection. This leads to the
control problems of frequency and voltage in the system and which leads to the failure of the
entire system. For the purpose of safe and secure operation of wind turbines, the design of wind
turbine is addressed by the fault so that the turbine is made to be connected to the network during
the time of the grid faults (Afifi et al., 2017). Sustainable advances are being viewed as what's to
come vitality advancements of the decision. In years to come, more breeze control plants will be
coordinated to the framework and subsequently exact figuring of energy framework streams,
what's more, voltages under blame conditions are basic to guarantee framework insurance is very
much planned and that the abilities of hardware for withstanding the short out current are most
certainly not surpassed. Albeit produced for a customary power framework with traditional age,
it is standard practice to utilize the Standard for computing the blame level in systems. Be that as
it may wind control plants have particular highlights that recognize them from regular
generators, the essential contrast being that the essential drive source, i.e. the breeze speed, is
variable and discontinuous (Patel et al., 2017). Notwithstanding these stochastic varieties in
21

wind, the 3p impact in twist turbines because of tower shadow and wind shear additionally result
in occasional variances in twist speed at the rotor sharp edges of a breeze turbine. This
investigation is persuaded by the way that the short out current commitment from a breeze
turbine is a component of the inner voltage of the generator at the moment of blame and the
impedance to blame, the last being a consistent amount. The inner voltage of the generator
increments with the expansion of wind speed. For stochastic varieties in wind speed, this
increment would be little and will not bring about a huge variety in the blame current level, as
appeared by reproduction. In any case, if the breeze turbine is associated with a feeble network,
the 3p recurrence in the scope of 0.5-2 Hz result in changes in framework RMS voltage at the
purpose of basic coupling. These voltage vacillations will be additionally articulated when all the
breeze turbines in a breeze cultivate are in synchronism. Accordingly, the inner voltage of the
breeze turbine generator encounters extreme changes and the most extreme and least blame
current level at the moment inside voltage is greatest and least might be influenced. This is
examined and they infer that under an intensely stacked condition, wind speed vacillation in
every unit may have a generous impact on resultant short out current. Be that as it may, no rules
have been given with respect to how it impacts the defensive transfer coordination and electrical
switch appraisals. In view of the previously mentioned foundation, the goal of this paper is to
show how the breeze speed variety influences the blame current levels of a wind turbine and
what effect it has on the framework insurance settings. Five contextual analyses of a settled
speed wind turbine associated with the lattice have been exhibited in PSCAD. The concentrate is
on settled speed twist turbines since the commitment of sort I twist turbines amid the underlying
cycle of the blame can be as high as at least 6 times the evaluated current. The first three
contextual analyses think about the effect of stochastic variation in twist speed on blame levels
while the rest of the contextual analyses examine the effect of wind speed variety due to 3p
impact on hamper commitment of the breeze turbine. For each contextual analysis, the greatest
and least conceivable beginning symmetrical current has been ascertained. Utilizing these
qualities, a range for the pinnacle current is developed. Next, adjusted symmetrical shortcomings
are recreated in the PSCAD display and the pinnacle blame current at various breeze speeds is
noted. The objective is to contrast the reenactment comes about and the hypothetically figured
breaking points for the pinnacle current; decide if there is a critical distinction in blame streams
at various breeze speeds and if the change is sufficiently noteworthy for thought in cut off.
22

Control and protection of DFIG wind turbine system configuration under grid faults
The wind turbine can be controlled and protected by two ways of fault operation. They are
1. Wind turbine with the drive train, the aerodynamics and the pitch angle control system.
2. DFIG protection and control system during grid faults.
Figure 10 Configuration
The stability level of the DFIG is maintained and used in the grid fault.
Drive train, the aerodynamics, and the pitch angle control system
The drive train method is made equal to the two-mass model when the system response to the
high disturbances is analyzed. By using this two-mass model, the result of the wind turbine will
be much accurate in the grid faults and to get more accurate results in the prediction of the effect
on the power systems.
23

In this two-mass model, it is connected by the shaft having damping c and the stiffness k.
these damping and the stiffness are mentioned as a low-speed shaft. The high speed is considered
to be the stiff.
In the dynamic effect, the speed of the wind is kept consistent when the time frames are
observed since it is compared to the variations in the wind speed. The pitch angle control is
understood clearly by the PI controller. For the purpose of getting the actual response output
from the pitch angle control the servo mechanism is followed which explains about the servo
meter. In the non-linear aerodynamics features the gain scheduling control of the pitch angle
control is implemented.
Figure 11 Gain scheduling control
The generator speed that is the input given in the controller in the error signal between the
speed of the measured generator and the speed of the reference generator, is controlled by the
pitch angle control. In this way, the pitch angle control is implemented. During the high speed,
the speed is controlled by to the rated range and by increasing the pitch angle the aerodynamic
power is decreased (Vulin, Miličević and Burulic, 2017). Hence, this leads in the increment in
the stability of the generator. This type of control is used for the control of high speed in normal
condition as well as during the fault in the grid. The pitch angle directly controls the speed of the
generator. Here the rate of change of limitation plays a vital role in this speed control since the
high speed is controlled and protected by decreasing the aerodynamic power. The rate of the
pitch limit is set to the value of ten degrees per second (Coughlan, Smith and Mullane, 2017).
4.7 DFIG protection system during grid faults
24

The utilization of the incomplete scale converter to the generator rotor makes this idea, on
one hand alluring from a sparing perspective. Then again, this converter plan requires a propelled
assurance framework, as it is exceptionally delicate to unsettling influences on the network.
Without such insurance, high transient streams instigated in the rotor can harm the power
converter gadget (Saad, Mostafa, and Abderrahmane, 2017).
The control execution of the DFIG is extremely great in ordinary matrix conditions
permitting dynamic and receptive power changes in the scope of a couple of line periods. DFIG
control can, inside cutoff points, hold the electrical control consistent notwithstanding fluctuating
breeze, putting away subsequently briefly the quick variances in control as dynamic vitality. The
worry with DFIG is normally the way that huge aggravations prompt expansive blame streams in
the stator because of the stator's immediate association with the matrix (Tran-Quoc et al., 2017).
A reasonable assurance framework for the DFIG converter is subsequently fundamental to
break the high streams and the wild vitality move through the RSC to the DC connection and
subsequently to limit the impacts of conceivable strange working conditions (Zhao et al., 2017).
The assurance framework screens diverse flags, suppose, the rotor current and the DC interface
voltage; when no less than one of the observed signs surpasses its particular transfer settings, the
security is enacted. A basic assurance technique is to cut off rotor through a gadget called
crowbar. The crowbar assurance, particular to DFIG, is an outer rotor impedance, coupled by
means of the slip rings to the generator rotor rather than the converter. The capacity of the
crowbar is to constrain the rotor current (Infield and Wu, 2017).
4.8 Fixed speed wind turbine
With HVDC or VSC connection, fixed speed active stall wind turbine concept:
HVDC transmission system with VSC has been developed due to some particular attributes
namely continuous frequency and voltage regulation, independent control of active and reactive
power and black-start capacity (Muljadi et al., 2017). There are 2 main concepts are there. The
two main concepts are listed below.
1. HNDC plus which is improved by Siemens. To form twelve pulse bipolar group, 2 single
six pulse converters are used.
2. HVDC light which is based on six pulses bipolar voltage system controller having the
ratings up to three hundred and thirty megawatts.It is improved by ABB.
25

Figure 12 Bipolar HVDC plus transmission system circuit diagram
The bipolar HVDC plus transmission system is applicable for the power ratings of the
values up to two hundred megawatts for 1 bipolar unit having DC voltage of the ratings up to one
hundred and fifty-kilo volt.
Figure 13 HVDC light transmission system circuit diagram
The HVDC light transmission system having the power ratings in the range of three
hundred and thirty megawatts with DC voltage of one hundred and fifty-kilo volt for 1 bipolar
unit.
HVDC light and HVDC plus transmission system have 4 quadrant function in the plane
P-Q as well as decoupled control for the reactive and active power. At variable frequency, each
converter does function as inverter or converter as well as to deliver or absorb reactive power to
an alternating current grid.
Station A control
26

Implementing control scheme is the main target. For Micro Grid controller the control
scheme should have frequency and voltage set points. For Pulse modulation width converter
model, frequency and pulse width modulation index magnitude is utilized as control variables.
Every wind turbine has various values because of wind speed. Therefore, for frequency and
voltage, various function points the droop control. According to the variations of wind speed,
every wind turbine can absorb the reactive power and deliver the active power. Therefore, for
reactive power, voltage stability is not dependent on demand.
The value of voltage reference is determined by using the formula as
Here, kp means voltage droop coefficient
Figure 14 Sending end station control structure for wind farm
27

Figure 15 Graph of Voltage set point
With droop characteristics, voltage set point graph
For frequency, references is calculated as
Here, kf means, for frequency, the droop coefficient,
Station B control
Generally, pulse width modulation converter from grid side should control the reactive
power and DC link voltage in a grid-connected application. By using Dig SILENT, we
implement the control scheme in the transmission system.
Depends on applications, various DC link voltage control scheme is there. Droop control
or master or slave topology is used generally. For converter's parallel function, master or slave
control is utilized.
28

Figure 16 Receiving end station control structure
By using actual active power, we calculate the DC link voltage from droop characteristics
and DC link. In DC link voltage 5 percent variation is permitted. We measure the error signal in
between the set points. The measured value is fed to the PI controller. The error restoration is the
advantage of PI controller in droop control. The reference for current is the DC link voltage
controller output in d axis. The Error, which is in between the actual value and the reactive
power set point, is given to PI controller.
29

Figure 17 SVC control
5. Expected Outcome
Fixed speed active stall wind turbine with VSC or HVDC connection
The Matlab model of the fixed wind turbine is given with a three-phase programmable
source, Transformer and the wind turbine of induction type a capacitive load has been given the
circuit are modeled with a gain as shown in the figure. The turbine is given a step input.
30

The output of this wind farm can be shown as
First case
In the1st case, various events are there in the system.
1. In the interval of time period 60 to 120 seconds, the average speed of wind is enhanced from
11 meters per seconds to 16 meters per seconds. Hence, the wind turbine is process via active
stall controller three modes of operation.
2. At the period of time t=50 seconds, 100 percent increase in load. The value of load is 2.5
Mega Watt rated power.
3. At 0.8 power factor and turbine power of 0.7 p.u, CHP functions. The turbine's power set
point is enhanced to one p.u at the period of time t=300 sec.
For B station, reactive power set point will be 0.
In the sending end station, kf i.e. frequency drop coefficient is 0. So, fixed reference for 50
HZ frequency is utilized. For every wind turbine, wind turbine series and pitch angles are
illustrated in the below figure.
31

For every wind turbine, wind turbine series and pitch angles
The active stall controller performs because of produced power and wind speed which is
higher than that of rated value. Increase the pitch angle in order to limit power output. 300-
kilowatt overpower is permitted. For every turbine, the reactive and active power is illustrated in
below figure.
32

For every turbine, the reactive and active power
Power balance at connection point
This has to be seen that at 0 reactive power, the receiving end station functions.
33

DC transmission's frequency and voltage for station A and station B
The figure given below shows the DC link voltage. For DC link voltage, 1.5 percent
overshoot is there while the wind farm begins to transmit rated power. In DC link voltage,
control scheme permits 5 percent variation. The outcome represents that DC link voltage control
function properly.
DC link voltage
CHP output which in term of power factor and power will get finally which is shown in
below graph.
34

CHP output
It is noted that at constant power factor CHP functions even the turbine power setpoint
differ. The plant power factor is not exactly 0.8. This is because of the generator rated voltage
and parameters for excitation system.
2nd case
In the 2nd case, for sending endpoint, frequency droop coefficient is 0.02. The value of
frequency droop coefficient relates with ca. frequency 50.2 Hertz for wind farm maximum power
output. According to the active power produced, the frequency at wind farm bus bar differs.
35

For every wind turbine, the pitch angle and wind time series
For wind turbine, reactive and real power
36

In connection point, the reactive and active power
For DC transmission system, frequency, and voltage
It is to be noted that deviations from rated values are less than 0.5 percent for voltage and
frequency.
37

DC link voltage
CHP output
The results show that DC connection control functions properly.
38

Various frequency drop coefficient:
The various pitch angles are determined by the initial condition calculation for every turbine.
Hence, the fixed pitch angle is utilized for an entire wind turbine in order to determine droop
control for the sending end station.
Average frequency enhances with 0.4 percent corresponds to 50.2 Hertz frequency.
39

Using various droop coefficient, shaft speed for wind turbine
The shaft speed power spectral density of the wind turbine 1
40

For a wide range of wind speeds, additional examinations are required in order to find
control practice.
Variable speed doubly fed induction generator wind turbine at normal operation:
DFIG control:
The variable speed doubly fed induction generator is given a circuit shown in the figure
The reactive and active power is controlled by rotor current which is in the stator flux
reference frame. Via controlling I q ,rotor
means which is orthogonal to stator flux, the active power is
obtained. Via controlling d-component I d , rotor
means , the reactive power is obtained.
The overall output of the given circuit is shown as
41

The circuit consists of the wind farm with doubly fed induction generator the overall
output of the circuit in Matlab is shown, whereas the output using Dig SILENT is also given.
Reactive and active power decoupled control of doubly fed induction generator.
The step response of active power is measured on 30 Kilovolt grid shows better dynamic
performance.
The power flow inside the doubly fed induction generator
The simulation purpose is to show.
1. In electrical power, mechanical 3p fluctuation filter effect.
2. When DFIG varies in between over synchronous and synchronous operation, power flow via
rotor, grid, and stator.
42

In over synchronous and asynchronous functions, the simulated power via rotor, grid and
stator.
The wind speed 3p fluctuations are existing in system's mechanical part. In electric power, 3p
fluctuations in wind are invisible. By DFIF control, it can be reduced.
43

Electrical torque, generator speed, pitch angle and aerodynamic torque simulation
Wind turbine overall control
44

Turbulent wind speed, 10 percent turbulence intensity and mean 7 meters per second simulation
The speed controller is the major turbine controller in power optimization. To seek to
maximum power, the speed controller has fast and strong. It confirms that in order to absorb
maximum power, the speed of generator follows well the variable speed generator reference.
Turbulence wind speed, gusts, 10 percent turbulence intensity, mean speed 18 meters per second
simulation
Variable speed multi-pole PMSG wind turbine:
The circuit for the variable synchronous generator is given, it consists of a three-phase
programmable source, transformer, synchronous generator and feeder line which connects the
wind turbine to the source.
45

Under deterministic wind speeds, performance of the system
The overall output of the system is shown
With deterministic wind speed, simulation of a set of step response is performed in order to
determine the variable speed PMSG wind turbine controller performance.
46

Pitch angle, active power for step in wind of one meter per second from 12 meters per second
down to 5 meters per second, speed of generator and wind speed
Stator voltage, DC link voltage, reactive power for the grid for step in wind of one meter per
second from 12 meters per second down to 5 meters per second and generator reactive power.
47

It is observed that the grid side converter and generator reactive power production is controlled
independently. When the reactive power production of grid side converter is 0 then the
generator's reactive power requirement varied.
Pitch angle, wind speed, active power for step in one meter per second from 12 meters per
second up to 20 meters per second wind and generator speed.
48

Stator voltage, DC link voltage, reactive power of the grid for step in one meter per second from
12 meters per second up to 20 meters per second.
The three types of wind turbine are
Turbine-1
WTG – 2MW
Turbine-2
Doubly Fed Induction Generator – 2MW
Turbine-3
DFIG with variable rotor resistance – 2MW
The combined model in DigSILENT Software with three different windfarm is shown in below.
49

The output of short circuit calculation when three turbines are ON.
50

51

PQ curve diagram when three turbines are ON.
52

VQ curve diagram when three turbines are ON
53

VQ cosphi curve diagram when three turbines are ON
54

When turbine 1 is ON, and 2 and 3 are OFF,
Circuit diagram
55

Short circuit calculation
56

57

When 2nd turbine is ON, and 1 and 3 are OFF
Circuit diagram
58

Short circuit calculation
59

60

When 3rd Turbine is ON, and 1 and 2 are OFF,
Circuit diagram
Short circuit calculation
61

62

6. Work Plan
The project involves the distribution of the network energy incorporate renewable energy
source and to represent that network by a specialized Power system simulation with the help of
Dig SILENT. The work plan for Short circuit calculations in networks with large penetration of
distributed generation is divided into seven tasks. Its time duration is from 15th May 2017 to 6th
September 2017. The seven tasks of the dissertation are
1. Literature Review
63

2. Study of WT configurations and large WP penetration
3. Components specification data collection
4. Modeling in Dig SILENT
5. Analyze all the results
6. Compile the report
7. Proofread and Submit Work
In the task one Literature review, a lot of research is been done in the papers related to faults
in the short circuit and the impact of wind farms on the distribution network. Literature review is
made on the papers like Assessment of the Effects of Wind Farms Connected in a Power System,
Issues of Connecting Wind Farms into Power Systems, Short-circuit calculations in networks
with distributed generation, Impact of DFIG Wind Turbines on Short Circuit Levels in
Distribution Networks Using ETAP, Challenges of Increased Wind Energy Penetration in
Ireland.
In the second task, the study is made of the wind turbines and wind power. In this study, all
the technical challenges in the wind turbine and wind power are done. It aims at studying a large
penetration of the high voltage that is been generated from the wind farms and their impact on
the distribution network in case of short circuit.
In task three, all the components that are required for the project are collected. During the
data collection, the following factors confirm whether all the access are got for the relevant data,
share the reliability of the data, to develop a wind-specific standard according to the project
standard, to develop equipment according to the specification.
The fourth tasks are modeling the wind turbine with the Dig SILENT software. Dig SILENT
provides the wind turbine models in a different level and in a well-structured manner, this
combines the electromagnetic transient, a simulation tool. The modeling of the wind turbines
includes the mechanical, electrical and aerodynamics models. This software enables simulation
in the between the wind turbines and wind farm.
The fifth task is to analyze the results of the project. The results are to reduce the cost in the
industries and to reduce the technical problems, to analyze all the challenges that are related to
64

the failure of the short circuits. This also improves the protection of the power in the network
industry.
The sixth one is to compile the report, this helps to analyze the capability of the project. And
finally, the seventh task is to complete the proofreading and to submit the work
Figure 18 Gantt chart
65

Task Name Duration Start Finish
Literature Review 7 days Mon 5/15/17 Tue 5/23/17
Study of WT configurations and large WP
penetration 15 days Tue 5/23/17 Mon 6/12/17
Components specification data collection 14 days Thu 6/8/17 Tue 6/27/17
Modelling in DIgSILENT 21 days Fri 6/23/17 Fri 7/21/17
Analyze all the results 23 days Sat 7/15/17 Tue 8/15/17
Compile the report 21 days Tue 8/8/17 Tue 9/5/17
Proofread and Submit Work 7 days Wed 8/30/17 Thu 9/7/17
7. Conclusion
This research project deals with the wind turbines that are connected to a grid and generate
wind power in the network of wind turbines or farms. The effect of the wind farms depends on
the type of generator utilized. The wind farms that are linked to a network when any fault occurs
is analyzed. The effect of the fault in the farms is studied. Different types of elements utilized in
the wind turbines are identified. Simulation of turbines that are connected to the network of
distribution is done using Matlab. The effect of the wind turbines combined with the network in
the power system based on stability and power control is achieved. The effect of the wind energy
during the normal operation varies from the effect of wind energy during the short-circuit fault.
DFIG is utilized for the wind turbine for use in the grid connected wind farms. Variable speed of
the DFIG wind turbine when short circuit arises is analyzed and the process of operation is
defined. Then the fixed speed of the DFIG wind turbine when the short circuit arises is
calculated and the process is defined. Even the synchronizing generator is also utilized for the
grid in which wind turbines are linked. The variable and the fixed speed of the wind turbines
when short circuit arises are analyzed and simulated. The stability of the system is maintained
constant and the power generation is improved. The generator utilized here is the DFIG, which is
66

very easy for the wind turbines to achieve the result. DFIG is widely utilized nowadays due to its
variation of the operations. DFIG is better than any other generator utilized in wind turbines. The
control during the grid fault is identified. The mechanism of the wind turbine is done by
supporting the stability of the grid and protecting the wind turbine. The short circuit calculations
in networks with the distributed generator are done. The power protection of the distributed
network is improved by using the DFIG wind turbine. The information related to the different
configurations of turbines and information of distributed wind turbines are gathered together and
analyzed. The network interconnected to several wind farms are simulated using the Matlab.
Short circuit and the load flow analysis are performed and achieved. The result of different
generators utilized is compared and the result is obtained.
8. Bibliography
Abdelbar, F., Alaboudy, A., El-Zohri, E. and Mahmoud, H. (2017). Improved Protection
Schemes for DFIG Based Wind Turbines during the Grid Faults.
Afifi, S., Wang, H., Taylor, G. and Irving, M. (2017). Impact of DFIG Wind Turbines on
Short Circuit Levels in Distribution Networks Using ETAP.
Alluri, H., Tummala, A. and Ramanarao, P. (2017). Performance of the Wind Farm for
Various Faults.
Amora, M. and Bezerra, U. (2017). Assessment of the Effects of Wind Farms Connected in a
Power System.
Anaya-Lara, O., Hughes, F., Jenkins, N. and Strbac, G. (2017). Influence of Windfarms on
Power System Dynamic and Transient Stability.
Azmy, A. and Erlich, I. (2017). Impact of Distributed Generation on the Stability of
Electrical Power Systems.
Babaie Lajimi, A., Asghar Gholamian, S. and Shahabi, M. (2017). Modeling and Control of a
DFIG-Based Wind Turbine During a Grid Voltage Drop.
Bazilian, M., Denny, E. and O’Malley, M. (2017). Challenges of Increased Wind Energy
Penetration in Ireland.
Boutsika, T. and Papathanassiou, S. (2017). Short-circuit calculations in networks with
distributed generation.
Cai, L., Erlich, I. and Fortmann, J. (2017). Dynamic Voltage Stability Analysis for Power
Systems with Wind Power Plants using Relative Gain Array (RGA).
Chaudhary, A., Gupta, S. and Rizwan Khan, M. (2017). Fault Analysis of DFIG under Grid
Disturbances.
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Chen, Z. (2017). Issues of Connecting Wind Farms into Power Systems.
Cossent, R., Go´mez, T. and Frı´as, P. (2017). Towards a future with large penetration of
distributed generation: Is the current regulation of electricity distribution ready? Regulatory
recommendations under a European perspective.
Coughlan, Y., Smith, P. and Mullane, A. (2017). Wind Turbine Modelling for Power System
Stability Analysis—A System Operator Perspective.
Davoudi, M., Cecchi, V. and Agüero, J. (2017). Increasing Penetration of Distributed
Generation with Meshed Operation of Distribution Systems.
Dolan, B. (2017). Wind Turbine Modelling, Control and Fault Detection.
El-Naggar, A. (2017). Standard Calculation of Fault Current Contribution of Doubly Fed
Induction Generator-Based Wind Turbine.
EL-Tamally, H., Sultan, H. and Azzam, M. (2017). Performance of DFIG Variable Speed
Wind Turbines under Grid Fault Conditions.
Eping, C., Stenzel, J., P¨oller, M. and Muller, H. (2017). Impact of Large Scale Wind Power
on Power System Stability.
Feynman, R. (2017). Transient Stability Analysis for Power System Networks with
Asynchronous Generation.
Gevorgian, V. and Muljadi, E. (2017). Wind Power Plant Short Circuit Current Contribution
for Different Fault and Wind Turbine Topologies.
Giaourakis, D., Safacas, A. and Tsotoulidis, S. (2017). Dynamic Behaviour of a Wind
Energy Conversion System including Doubly-Fed Induction Generator in Fault Conditions.
Gohil, H., Mehta, C. and Vora, S. (2017). Short Circuit Current Comparison ofDFIG during
Symmetrical Faults with Different Wind Speeds.
Gohil, H., Mehta, C. and Vora, S. (2017). Short Circuit Current Comparison ofDFIG during
Symmetrical Faults with Different Wind Speeds.
Guan-yang, L., Hongzhao, W., Guanglei, L., Yamei, C., Hong-zheng, L. and Yi, S. (2017).
Security and Stability Analysis of Wind Farms Integration into Distribution Network.
Hansen, A., Cutululis, N., Markou, H., Sørensen, P. and Iov, F. (2017). Grid fault and
design-basis for wind turbines - Final report.
Heising, K. and Remler, S. (2017). Analysis of System Stability in Developing and Emerging
Countries.
Holdsworth, L., Wu, X., Ekanayake, J. and Jenkins, N. (2017). Comparison of fixed speed
and doubly-fed induction wind turbines during power system disturbances.
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Honrubia-Escribano, A., Jiménez-Buendía, F., Molina-García, A., Fuentes-Moreno, J.,
Muljadi, E. and Gómez-Lázaro, E. (2017). Analysis of Wind Turbine Simulation Models:
Assessment of Simplified versus Complete Methodologies.
Hossain, M., Pota, H., Mahmud, M. and Ramos, R. (2017). Investigation of the Impacts of
Large-Scale Wind Power Penetration on the Angle and Voltage Stability of Power Systems.
Huda, A. and Živanović, R. (2017). Large-scale integration of distributed generation into
distribution networks: Study objectives, review of models and computational tools.
Infield, D. and Wu, L. (2017). The Challenges of High Wind Energy Penetration in the UK
Power System.
Jeevajothi, r. (2017). Impact of wind turbine generators on power system stability.
Kalyan Kumar, B. (2017). Power System Stability and Control.
Kazachkov, Y. and Stapleton, S. (2017). Modeling wind farms for power system stability
studies.
Kazachkov, Y., Feltes, J. and Zavadil, R. (2017). Modeling Wind Farms for Power System
Stability Studies.
Liu, W., Ge, R., Li, H. and Ge, J. (2017). Impact of Large-Scale Wind Power Integration on
Small Signal Stability Based on Stability Region Boundary.
Margossian, H. and Sachau, J. (2017). Short Circuit Calculation in Networks with a High
Share of Inverter Based Distributed Generation.
Milano, F. (2017). Assessing Adequate Voltage Stability Analysis Tools for Networks with
High Wind Power Penetration.
Mishra, S., Shukla, S. and S.L, S. (2017). Performance Analysis and Limitations of Grid
Connected DFIG Wind Turbine under Voltage Sag and 3-Phase Fault.
Mishra, Y., Mishra, S., Li, F., Dong, Z. and Bansal, R. (2017). Small-Signal Stability
Analysis of a DFIG-Based Wind Power System Under Different Modes of Operation.
Morel, J., Obara, S. and Morizane, Y. (2017). Stability Enhancement of a Power System
Containing High-Penetration Intermittent Renewable Generation.
Müfit, A., Anca Daniela, H., Ömer, G., Nicolaos Antonio, C. and Poul Ejnar, S. (2017).
Wind Turbine and Wind Power Plant Modelling Aspects for Power System Stability Studies.
Muljadi, E., Samaan, N., Gevorgian, V., Li, J. and Pasupulati, S. (2017). Different Factors
Affecting Short Circuit Behavior of a Wind Power Plant.
Muljadi, E., Samaan, N., Gevorgian, V., Li, J. and Pasupulati, S. (2017). Short Circuit
Current Contribution for Different Wind Turbine Generator Types.
Noureldeen, O. (2017). Behavior of DFIG Wind Turbines with Crowbar Protection under
Short Circuit.
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Odgaard, P. and Stoustrup, J. (2017). Frequency Based Fault Detection in Wind Turbines.
Patel, D., Varma, R., Seethapathy, R. and Dang, M. (2017). Impact of wind turbine
generators on network resonance and harmonic distortion.
Pillai, A., P C, T., K, S., Baby, S., Sreedharan, S. and Joseph, T. (2017). Transient Stability
Analysis of Wind Integrated Power Systems with Central Area Controller.
Poller, M., Achilles, S. and Moodley, G. (2017). Variable-Speed Wind-Generator Models for
Power System Stability Analysis.
Potamianakis, E. and Vournas, C. (2017). Aggregation of Wind Farms in Distribution
Networks.
Prusty, B., Panigrahi, C. and Ali, S. (2017). Study of fault analysis in a doubly fed induction
generator wind energy conversion system.
Saad, c., Mostafa, b. and Abderrahmane, h. (2017). Performance analysis of faults detection
in wind turbine generator based on high-resolution frequency estimation methods.
Santana, M., Almeida Monteiro, J., Paula, G., Almeida, T., Romero, G. and Faracco1, J.
(2017). Fault Identification in Doubly Fed Induction Generator Using FFT and Neural
Networks.
Sasi, C. and Mohan, G. (2017). Performance Analysis of Grid connected Wind Energy
Conversion System with a DFIG during Fault Condition.
Sharma, K., Bhargava, A. and Gajrani, K. (2017). Stability Analysis of DFIG based Wind
Turbines Connected to Electric Grid.
Shi, L., Dai, S., Yao, L., Ni, Y. and Bazargan, M. (2017). Impact of Wind Farms of DFIG
Type on Power System Transient Stability*.
Shi, L., Xu, Z., Wang, C., Yao, L. and Ni, Y. (2017). Impact of Intermittent Wind Generation
on Power System Small Signal Stability.
Subbu Lakshmi, S. (2017). Voltage Stability Assessment of a Power System Incorporating
Wind Turbine Using Power System Analysis Toolbox (Psat).
Sulla, F. (2017). Fault Behavior of Wind Turbines.
Tran-Quoc, T., Le Thanh, L., Andrieu, C., Hadjsaid, N., Kieny, C., Sabonnadière, J., Le, K.,
Devaux, O. and Chilard, O. (2017). Stability analysis for the distribution networks with
distributed generation.
Tsai, S., Lin, C. and Tseng, Y. (2017). Small Signal Stability Analysis of the Wind Farm
Integrated Power System in Penghu Island.
Tung Linh, N. and Chuong, T. (2017). Voltage stability analysis of grids connected wind
generators.
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Vittal, E., Keane, A., Slootweg, J. and Kling, W. (2017). Impacts of Wind Power on Power
System Stability.
Vulin, d., Miličević, k. and Burulic, z. (2017). Simulation of impact of a wind farm on the
grid stability using powerworld simulator.
Wang, X., Chiang, H., Wang, J., Liu, H. and Wang, T. (2017). Long-Term Stability Analysis
of Power Systems with Wind Power Based on Stochastic Differential Equations: Model
Development and Foundations.
Williams, J. and Karlson, B. (2017). Wind Power Plant Short-Circuit Modeling Guide.
Yasa, Y., Isen, E., Sozer, Y., Mese, E. and Gurleyen, H. (2017). Analysis of doubly fed
induction generator wind turbine system during one phase-to-ground fault.
Zerzouri, N., Labar, H. and Kechida, S. (2017). Simulation Study of DFIG Wind Turbine
under Grid Fault.
Zhang, D. and Yuan, X. (2017). Optimization of Active Current for Large-Scale Wind
Turbines Integrated into Weak Grids for Power System Transient Stability Improvement.
Zhao, Y., Li, D., Dong, A., Kang, D., Lv, Q. and Shang, L. (2017). Fault Prediction and
Diagnosis of Wind Turbine Generators Using SCADA Data.
Zheng, C. and Kezunovic, M. (2017). Impact of wind generation uncertainty on power
system small disturbance voltage stability: A PCM-based approach.
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