Power System Stability with Renewable Energy

This assignment delves into the complexities of maintaining power system stability in the face of increasing renewable energy integration. It examines the inherent variability of sources like wind and solar, their impact on grid frequency and voltage, and potential solutions to ensure reliable power supply. Topics covered likely include control strategies, energy storage, grid modernization, and the role of ancillary services.

Power systems with renewable generation
Renewable Energy Integration into the Grid
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Abstract— Renewable energy is discontinuous as a
result of climate conditions and land highlights. The
change of the yield of the renewable energy generation
must be alleviated in light of the fact that it forces strain
on the framework and antagonistically influences control
quality
Keywords—photo voltaic, solar, grid,
I. INTRODUCTION
Distributed generations (DG) including renewable energy
are the arrangements for the preventing the consistently
expanding issue of greenhouse gasses. Be that as it may, the
power created by wind turbine and photovoltaic framework has
vast vacillations due to climate conditions and geological
highlights. In this way, it can have terrible effects on control
framework and electric power quality. With a specific end goal
to take care of these issues, the battery energy capacity system
(BESS) is a noteworthy instrument. It helps to keep the power
balance by reducing the radical output. Grid-associated PV
generation must be sent out to control utilities when
coordinated yield meets the direction conditions. One of the
direction conditions is identified with variance rate. The
vacillation rate changes relying upon the nation or district and
there are different strategies to balance out the yield utilizing
BESS. Methods like Normal Ramp Rate (NRR), Continuous
Moving Average (CMA) and Step Ramp Rate (SRR).
A synchronous power controller for grid-associated
converters is proposed as a decent answer for the sustainable
age frameworks with vitality stockpiling. It gives latency,
damping and adaptable hang qualities. Not quite the same as
the reliable replication of the swing condition of synchronous
machines, an option control structure is proposed, by which the
damping and natural hang slant can be arranged freely to meet
the prerequisites in the two progression and recurrence
directions. In view of the general control structure, the idleness
can be basically fused in the electromechanical control circle
by appropriately outlining the power circle controller.
The synchronous power controller with inertia, damping
and adaptable hang qualities for grid-associated control
converters. The proposed controller demonstrates greater
adaptability contrasted and the current latency copying
systems, since it stays away from the limitation between the
damping and hang attributes in the power directing circle. In
this way, an external P-f hang controller joined by a devoted
PLL isn't required for any operation arrange, and the exchange
off in outlining the transfer speed of the hang circle low-pass
channel is kept away from. Additionally, the settled power
control can be effortlessly accomplished despite grid
recurrence varieties.
The idea of RTDA of energy frameworks with VER
generations. The physical translation of RTDA is the maximal
capacity of the power framework to suit dubious VER changes
in RTD, or a security district in the vulnerability space, which
is like the dispatch-capable area proposed. We depict the
contrasts amongst RTDA and the dispatchable district
underneath. In the essential setting of the dispatchable area, the
current generation and save portfolio are given by a joint
vitality and save dispatch issue. In the event that a generator
does not offer save limit, its yield is a consistent in RTD. Note
that the ideal save limit offered by each generator relies upon
the foreseen vulnerability in the vitality and save dispatch
issue, say the vulnerability set or some examined situations,
which are some way or another subjective. In addition, in the
dispatchable locale issue, the corrective activities are thought to
be for nothing out of pocket. In this paper, the RTDA expands
the dispatchable district in two ways. From one viewpoint, all
generators are thought to have the capacity to change their
yield in RTD subjecting to their sloping breaking points and
producing limits. Also, RTDA explicitly considers the cost of
RTD, which is disregarded.
The principal expansion makes RTDA not to depend on
subjective suppositions on the basic vulnerabilities of VER
ages. The second augmentation joins financial contemplations,
which is imperative in assessing flexibilities. They make
RTDA all the more near the genuine circumstance of RTD. Be
that as it may, the previous expansion will present more choice
factors in RTD; the last augmentation will, by and large,
present a greater number of limits in RTDA than the
dispatchable area. Along these lines, the necessity on the
computational productivity is all the more requesting.
An effective calculation to figure RTDA. RTDA is an
arrangement of dubious nodal infusions that won't cause
infeasibility in RTD. Processing such an area is variant from
tackling an enhancement issue. We give an express polyhedral

type of RTDA. The dispatchable locale is a polytope, yet does
not uncover its shut frame. To satisfy the necessity on the
computational productivity, we propose an Ad-CG calculation
to recover the limits of RTDA. The Ad-CG calculation in this
paper has diverse scientific foundation contrasted and the
calculation. The upside of the Ad-CG calculation is that it
never again requires finding the limit point in every emphasis,
in this manner the computational productivity can be upgraded
surprisingly. A MILP-based prophet, and additionally an
iterative direct genius gram (ITLP)- based prophet, is
recommended to execute the Ad-CG technique.
To enhance the change proficiency and accomplish a high
advance up voltage increase, many single power organize
topologies have been revealed as of late. One such class is the
exchanged capacitor converter (SCC). The fundamental
weaknesses of the SCC topology are that the info current is
throbbing, the dc voltage change proportion is fundamentally
controlled by the circuit structure, and the voltage direction
capacity is frail and troublesome within the sight of wide load
varieties.
Coupled inductor innovation is used in another class of
converters. Be that as it may, the spillage inductance of the
coupled inductor and the parasitic capacitor of the yield diode
will reverberate together, and an appropriate censure circuit is
required to assimilate the voltage ringing on the yield diode,
and the utilization of extra security circuits with two dynamic
switches increments both the cost and multifaceted nature of
the circuit. Furthermore, the throbbing info present and high
pinnacle current that course through the cinch capacitor
realizes more power misfortune.
There are two broadly received ac– dc converter topologies
in SWTs outfitted with PMSGs: a diode rectifier with dc– dc
support converter and a two-level voltage source converter
(2L-VSC). The first is the most well-known and minimal effort
arrangement, yet it permits just unidirectional power stream.
This infers extensive consonant substance in generator current,
causing higher copper misfortune and torque swell. Then again,
the control structure and its execution are straightforward. It by
and large comprises of an external rotational speed circle with
a proportional– necessary (PI) controller and an interior
inductor current circle with a moment PI controller. The 2L-
VSC is portrayed by a more perplexing control and higher cost.
In any case, the unwavering quality and proficiency of the
generator are expanded because of sinusoidal winding streams.
Also, bidirectional power stream guaranteed by the 2L-VSC
makes it conceivable to use a minimal effort IG.
Field-arranged control is the most advantageous control
plot connected for a 2L-VSC. The square plan of a control
calculation. In this plan, the reference speed is contrasted and
assessed rakish speed. The speed mistake is the info motion for
the PI controller that figures the reference an incentive for the
present in charge of electromagnetic torque. Reference current
id ref is set to zero. The PI current controllers in the inward
control circles set converter reference voltage segments. These
voltages, after change from synchronous turning to stationary
directions framework, are voltage reference esteems for PWM.
HASWTs, because of their great harmony between
execution, cost, and dynamic properties, are overwhelming,
which is additionally noticeable in the exhibited examination.
Be that as it may, VASWTs have been picking up fame as of
late since the new class of urban WTs is requested by the
market.
The plan of SWT geometry is a multi-objective procedure,
be that as it may, the most essential factor is the vitality yield
over a long time scale. This implies turbine outlines for bring
down breeze speeds are significantly more critical as far as
potential vitality pick up.
The multipole low-speed PMSG is the most as often as
possible utilized sort of generator in SWTs because of its high
effectiveness. Nonetheless, a critical issue amid development is
the minimization of cogging torque, which has a critical impact
on the aggregate effectiveness of the framework, especially at a
low breeze speeds. The most critical minimization of cogging
torque is gotten through the use of an uneven number of stator
grooves and magnets in the rotor.
The flow research and industry patterns for control
hardware converters utilized as a part of SWTs concentrate on
a few imperative viewpoints, including cost, misfortunes,
disappointment rate, weight, what's more, volume. The ac– dc
converters are most as often as possible collected by a diode
rectifier and dc– dc support converter, which is a basic and
shoddy arrangement. Nonetheless, suitable dependable control
with a lessened number of sensors is likewise an extremely
vital issue for this situation since generator rotational speed
must be controlled by a MPPT calculation to separate most
extreme vitality. The errand is accomplished by incremental
MPPT, where the calculation is self-altering (no earlier
learning of the turbine parameters is required).
The most every now and again utilized dc– air conditioning
converters are single phase H-scaffold and three-stage 2L-VSC
with an extra delta-wye transformer, which takes into account
providing the topsy-turvy stack in the remain solitary method
of operation. Be that as it may, such a transformer altogether
expands the cost of establishment. In this way, present day
arrangements ought to incorporate a four-leg converter.
Another critical piece of the superior dc– air conditioning
vitality transformation framework is the control calculation.
The most astounding execution, particularly with twisted grid
voltage, is acquired with DPC-SVM and VOC in SCS, where
PR controllers are utilized with numerous PR compensators in
parallel, which are tuned at particular high order harmonics,
e.g., fifth and seventh.
Grid-associated wind control and photovoltaic (PV)
sources, which are as a rule progressively retained into regular
power frameworks, are alluring sustainable power source
choices for huge scale applications. Associating these sources
to the grid has implied huge effect on control framework flow
and operational qualities, including little flag soundness. A few
examinations exploring the effect of wind age [3]– [6] and PV
age [7]– [9] on control framework little flag solidness have
reasoned that the trademark change of sustainable power
source assets is a basic factor impacting the solidness of the
control framework. Specifically, the high entrance of

inexhaustible vitality asset age changes the dependability amid
the dynamic operational process. As of now, there are few
investigations that inspect the web based following of the
changing dependability of a control framework that
consolidates sustainable power source age.
Web based following, a critical choice apparatus for
framework administrators, can propose ideal healing activities
that can be taken for any close shakiness or precarious
electromechanical motions in transmission systems. The
improvement of this device, in this way, is basic for an
enhanced investigation of the little flag solidness of energy
frameworks that join sustainable wellsprings of age [5].
Hybrid powers systems offer a state of the art systems with
renewable energy hence are yet another fundamental aspect
that would give finer insight into this task. In a broader sense,
hybrid power systems can be defined as a power system that
makes use of a renewable and a conventional source of energy
or even more than a single renewable energy source and no
conventional source of energy working in a grid connected
mode or as a stand-alone. The main characteristics of
renewable energy sources are variability and random
behaviour in as much as there exist certain cyclic recurrence
and regularity in their behaviour. Normally, there is no
similarity in the intensity of the various sources of energy
since as a source becomes more intensive, another is found to
be more extensive. The meteorological conditions of a given
areas are an integral part in the intensity and the distribution
time of the sources of renewable energy.
HSRES are normally used in the generation of energy objects
that are a distant from the energy source and are not connected
to common distribution system of electricity [14]. An example
of such a case scenario is the distribution of electrical energy
to an island, houses, villages, hotels or even the supply of
energy to other stations such as telecommunication, research
laboratories and meteorological stations among other stations.
Hybrid powers systems have found wider applications as grid
connected systems and this is attributed to the efficiency in the
usage of disposable renewable energy as an advantage.
Classification of HSRES
Various criteria are used in the classification of HSRES
systems among them;
Presences of conventional sources of energy: it is found that
hybrid systems that have convention sources of energy are
more responsible and powerful while those without the
conventional energy sources have relatively low power even
though they are as well responsible. With proper design of the
systems without conventional sources of energy, sustainable
energy can still be generated
Number of sources: The complexity of a hybrid system is
determined by the number of sources of energy it has besides
its efficiency and sustainability. Whereas numerous sources
complicates the system, the sources as well make the system
more efficient in terms of energy as well as sustainable.
Energy type produced: Various types of energy are produced
by various hybrid systems. Such energy types include
mechanical, thermal, light, electrical, fuel production as well
as mixed. Mixed typed of energy could the case of a system
comprising of both wind turbines combined with solar thermal
collector and photovoltaic [10]. Light is used in the provision
of daylight in various buildings by the use of optic cable and
concentric collector. Thermal energy is important in the
warming and heating up of water. This system can run on both
geothermal energy and solar thermal collectors. Electrical
sources of energy allow for ease of distribution and storage to
any type of choice. It is possible to store it and be used in case
need arises. Fuel production occurs in cases where hydrogen
is being produced by means of electrolysis.
According to the power rating: systems whose ratings are
lower than 1kW are normally used in stations such as
telecommunication and meteorological while middle power
i.e. ratings greater than 1kW but less than 10kW are used in
supplying houses and hotels[7]. Still, high power ratings i.e.
ratings more than 10kW are efficient in supplying isles,
villages and towns specifically those that are in remote areas
not easily accessible by electricity distribution systems.
According to amount of energy stored: Whereas some systems
have storages for energy, others do not. Those without energy
storages are found to be less profitable as their needs may not
necessarily be consistent with the availability of energy. In
this case, some amounts of energy usually remain unused and
chances of load remaining without supply are high. As for the
case of those with energy storages, the excess electric power is
normally stored and dispensed should there need be [15]. That
way, the fluctuating nature of the RES is controlled hence
improving the efficiency of the hybrid system. The energy
can be stored in such forms as thermal e.g. in boilers,
mechanical as in flywheels, electrical as in batteries, potential
for the case of water towers or even as fuel conversion as in
hydrogen.
Fuel cells are important in the provision of clean technology
that deploys oxygen from the air and hydrogen from fuel
sources in the generation of heat and electricity. An operation
temperature range of between 800 to 1000⁰C is ideal for fuel
cells which are suited for DP and can deliver up to 80%
efficiency in CHP modes
The last criterion of classification of HSRES is on the basis of
the connection to the distribution grid. Those connected to the
grid must be synchronized with the channel of distribution
whereas the stand alone systems are used in supplying remote
areas that electricity distributions systems may not be able to
access.
Electrical HSRES
Hybrid systems are defined as either AC, DC or mixed
depending on the configuration and type of power buses
installed on them. Still they can be classified as parallel and
serial. In a serial nybrid system, flow of energy is
unidirectional i.e. energy flows in one directional only and
passes throughout the system structure as illustrated in the
figure below.

For the case of a parallel structure of hybrid system, the flow
of energy is in either direction. A parallel structure of a hybrid
system is as illustrated.
A number of challenges are faced by HSRES as a result of
their characteristics of the renewable sources of energy more
specifically with their variability. Modular HSRES has been
created as a result of the need to unification. Modular HSRES
are of stand information bus and possess standard power and
are always subjected to uniform supervisory control [16].
These units are always connected in parallel. Among the
advantages of the modular systems highly levels. They are
designed in such a way that they show stable parameters as
well as very sustainable of the energy produced from the
system. Using modular technology, local micro-grids and
mini-grids can be created in which the most widely used
Flexible AC Transmission Systems that are commonly used
are of different types among them SPS, STATCOM, UPFC,
TCSC and SVC. These systems have increased stability as
well as flexibility. It is expected that FACTS functions and
inverters may be integrated into these modular systems.
Types of Hybrid Systems
A Wind-Diesel system is one of the typical representatives of
high power hybrid system. Wind Diesel system is in most
cases used in supplying power to buildings and villages which
are not reachable by electricity distribution system. In places
where solar and wind energy are found to be having balanced
potentials, wind photovoltaic diesel system is found to be the
most suitable in such terrains. This system is of very high
effectiveness besides its complex nature [9].
The resources of wind photovoltaic systems have more of
favourable distribution into time. This is such that under such
circumstances as when wind becomes stronger, solar radiation
is found to reduce while when winds weaken the solar
radiation is increased [3]. This has been an observed trend
throughout the yearly round of the earth. In order to improve
the efficiency and steadiness of operation of the system it
should be correctly designed and proper energy storage
provided.
A combination of solar thermal collector and wind
photovoltaic system provide a more profitable system. In such
a combination, the electrical power generated by the RES is
consumed from one end by the loads and on the other by the
solar circulating paths. Any surplus energy produced by the
wind turbines may be useful in additional heating up the water
as opposed to an alternative of losing it dump load. This
complex system is most suitable for use in mountain chalets,
hotels and villas. This configuration may not reveal all the
available possibilities of HSRES structure but instead the
structure to be chosen depends on a number of factors
including energy needs, price, and potential of renewable
energy as well as the purpose of the system.
Design of Hybrid Systems
In the design of hybrid systems, the first and most important
consideration is given to the potential of the renewable energy
which is usually external to the system. The most appropriate
configurations of the HSRES is then sought based on factors
that are internal to the system As well as information on
measurements received from a meteorological department.
The configuration should be such that it ensures highest return
on investment, sustainability of the system while working,
highest attainable efficiency as well as the lowest knockdown
price. Some of the internal factors include;
Energy storage: This is normally done by batteries. it is
important to ensure intensive consumption and picking out
correctly of the battery capacity. Failure to observe such may
result into the interruption of the supply of power in the
system. In cases of very high capacity, the battery may not be
exhaustively used. A stored energy range of between 30 to
85% of the rated capacity is most appropriate in the choice of
the battery.
Energy consumption: the consumption should be checked
besides its distribution into the system to ascertain that the
energy supply is such that is uniformly distributed in the
hybrid system.

Unit selection: This is done in line with the provided specific
methodologies of the type of unit used in the system. The
various unit types include turbine and photovoltaic among
other unit types. From the above internal factors, it can be
deduced that the design of a hybrid system is nit any simple
task but instead a complex and multifactor task that aims at
achieving optimum output. In order to successfully achieve
this task, it is of importance to take into account technological,
economical as well as technical criteria and considerations [8].
The design process is ascended and made more effective
through the creation of a computer model and the use of
computing machinery in coming up with the system.
Control
In the control of the energy systems with RES, it is important
to note that it is not possible to control the input indicators. As
a result of this, there is, limited control thereby raising the
need to introduce feedbacks into the system so as to enhance
its stability. The control can either be scattered, centralized or
even combined. Generators with conventional fuel, batteries
and their joint work are mostly subjected to control but such
controls can at times be quite complicated.
Control systems are either passive or active depending on their
course of action. Active control systems are used with hybrid
systems made up of a great number of components [13]. These
systems measure and calculate input data such as energy
flows. Due to their flexibility, they are able to work in various
modes. Passive systems on the other hand works best with
simple HSRES and mostly work on an on/off principle.
Optimization and Modelling
An analysis of the multifactor target function is done in order
to identity an optimal configuration. Some of the functions
considered include:
Fuel consumption: This aims at finding a configuration that
gives maximum utilization of renewable energy as well as
minimizing the consumption of fuel. Such an optimization
aims at increasing the conformity of the system with the
ecolodge as well as reducing the stability and resulting into the
increase of the overall cost [16].
Cost of energy: The return on the investment is inversely
proportional to the energy costs thereby minimizing the cost of
energy results into maximization of the yield from the
investment
System sustainability: This aims at ensuring maximum
stability of the system such that there are as few interruptions
in the system as possible.
Err=f (Li, RE, PiSEmin, SEmax….)
The energy behaviour simulation has been used in the
optimization of sizing method in which is always incorporated
with a cost optimization. This simulation makes use of
numerical methods that are based on the energy balance as
well as the equations of storage continuity responding to
various configurations for the HSERS system. The inflation
rates are considered while doing the calculations of the
production costs during which a configuration with the lowest
rating is settled on [11].
The strategy flow controls, the size of the components of the
system, the threshold of the generator of the engine run off or
on are just but a few of the parameters that are optimized in
the design of a hybrid system. Various products can be used in
the simulation and optimization of hybrid systems. Among the
products include:
Hybrid Optimization Model for Electric Renewables: This
product models the system which is connected to the grid
power system as well as those that are not collected to the
grid. It can be used in modelling both for remote, distributed
and stand-alone generation systems. Sensitivity algorithms and
optimization are performed by this product thereby allowing
the designer to choose the best configuration of the system to
be designed.
Hybrid2: Designed for the study of the various types of hybrid
systems composed of various components. This program
allows for analysis using the economic analysis tool
configured with it. It provides results in two levels of output, a
summary as well as an elaborate time step by time step
describing the flow of power in the system [1].
Remote Area Power Supply Simulator: Designed in such a
way that it stimulates alternative options for the supply of
power. It is used in the sizing of wind, photovoltaic and diesel
stand-alone and hybrid systems.
In order to improve on the efficiency of the hybrid system,
they can be made more flexible. Flexible hybrid systems can
have their structure, control and mode changed depending on
the prevailing circumstances [4]. An experimental flexible
hybrid power system could be compromising of lead acid
battery, wind generator, inverter rectifier, photovoltaic and
digital meteorological station. In such a system the disposal
units can perform in different combinations. Monitoring
systems have been developed that allow for ease of monitoring
of the operations of the system besides the prevailing
meteorological conditions. The information collected from the
monitoring process is important in the analysis of how the
hybrid system would work when exposed to various weather
conditions thereby enabling the choice of the most suitable
strategy of control.
The wind generator is simulated using a motor-generator
group which has asynchronous generator of the same power
rating. This is done to increase the possibilities of the wind
diesel hybrid system. In so doing, it would be possible to
explore the behaviour of the system having had wind energy
potential as the preliminarily defined energy source. Charging
powers are treated as positive while discharging powers are
assumed to be negative [17].
Conclusion
Power systems with renewable energy sources are becoming
an increasing fast spreading trend. Hybrid systems with
renewable sources of energy are classified and the special
features and challenges that come with their design reviewed
and amicable solutions proposed. There has been a continuous
trend of decrease in the cost of renewable energy technologies
that has been attributed to a rise in the gravitation towards
distributed generation of energy. It is of importance to
consideration the configuration of the various types of HSRES
to ascertain the number of sources as well as the generation of
heat and electricity. Through the use of computer modelling it

is possible to design various hybrid systems under various
configurations and conditions.
REFERENCES
[1] Hyung-Joo Lee, Jin-Young Choi, Gun-Soo Park, Kyo-
Sun Oh and Dong-Jun Won, "Renewable integration
algorithm to compensate PV power using battery energy
storage system," 2017 6th International Youth Conference
on Energy (IYCE), Budapest, 2017, pp. 1-6.
[2] W. Zhang, A. M. Cantarellas, J. Rocabert, A. Luna and P.
Rodriguez, "Synchronous Power Controller With Flexible
Droop Characteristics for Renewable Power Generation
Systems," in IEEE Transactions on Sustainable Energy,
vol. 7, no. 4, pp. 1572-1582, Oct. 2016.
[3] W. Wei, F. Liu and S. Mei, "Real-Time Dispatchability of
Bulk Power Systems With Volatile Renewable
Generations," in IEEE Transactions on
Sustainable Energy, vol. 6, no. 3, pp. 738-747, July
2015.
[4] L. He and Y. Liao, "An Advanced Current-Autobalance
High Step-Up Converter With a Multicoupled Inductor
and Voltage Multiplier for a Renewable Power
Generation System," in IEEE Transactions on
Power Electronics, vol. 31, no. 10, pp. 6992-7005,
Oct. 2016.
[5] M. Malinowski, A. Milczarek, R. Kot, Z. Goryca and J. T.
Szuster, "Optimized Energy-Conversion Systems for
Small Wind Turbines: Renewable energy sources in
modern distributed power generation systems," in IEEE
Power Electronics Magazine, vol. 2, no. 3, pp. 16-
30, Sept. 2015.
[6] T. Wang, T. Bi, H. Wang and J. Liu, "Decision tree based
online stability assessment scheme for power systems
with renewable generations," in CSEE Journal of
Power and Energy Systems, vol. 1, no. 2, pp. 53-
61, June 2015.
[7] A. Tani, M. B. Camara and B. Dakyo, "Energy
Management in the Decentralized Generation Systems
Based on Renewable Energy—Ultracapacitors and
Battery to Compensate the Wind/Load Power
Fluctuations," in IEEE Transactions on Industry
Applications, vol. 51, no. 2, pp. 1817-1827, March-
April 2015.
[8] J. Pegueroles-Queralt, F. D. Bianchi and O. Gomis-
Bellmunt, "A Power Smoothing System Based on
Supercapacitors for Renewable Distributed Generation,"
in IEEE Transactions on Industrial Electronics,
vol. 62, no. 1, pp. 343-350, Jan. 2015.
[9] J. C. Wu, K. D. Wu, H. L. Jou and S. K. Chang, "Seven-
level active power conditioner for a renewable power
generation system," in IET Renewable Power
Generation, vol. 8, no. 7, pp. 807-816, September
2014.
[10] P. Acuña, L. Morán, M. Rivera, J. Dixon and J.
Rodriguez, "Improved Active Power Filter Performance
for Renewable Power Generation Systems," in IEEE
Transactions on Power Electronics, vol. 29, no. 2,
pp. 687-694, Feb. 2014.
[11] J. Liang, D. D. Molina, G. K. Venayagamoorthy and R.
G. Harley, "Two-Level Dynamic Stochastic Optimal
Power Flow Control for Power Systems With Intermittent
Renewable Generation," in IEEE Transactions on
Power Systems, vol. 28, no. 3, pp. 2670-2678, Aug.
2013.
[12] J. M. Shen, H. L. Jou, J. C. Wu and K. D. Wu, "Five-
Level Inverter for Renewable Power Generation System,"
in IEEE Transactions on Energy Conversion, vol.
28, no. 2, pp. 257-266, June 2013.
[13] J. Skea, D. Anderson, T. Green, R. Gross, P. Heptonstall
and M. Leach, "Intermittent renewable generation and
maintaining power system reliability," in IET
Generation, Transmission & Distribution, vol. 2,
no. 1, pp. 82-89, January 2008.
[14] A. Dysko, C. Booth, O. Anaya-Lara and G. M. Burt,
"Reducing unnecessary disconnection of renewable
generation from the power system," in IET Renewable
Power Generation, vol. 1, no. 1, pp. 41-48, March
2007.
[15] X. Xiong, C. K. Tse and X. Ruan, "Bifurcation Analysis
of Standalone Photovoltaic-Battery Hybrid Power
System," in IEEE Transactions on Circuits and
Systems I: Regular Papers, vol. 60, no. 5, pp. 1354-
1365, May 2013.
[16] X. Liu, Y. Han and C. Wang, "Second-order sliding mode
control for power optimisation of DFIG-based variable
speed wind turbine," in IET Renewable Power
Generation, vol. 11, no. 2, pp. 408-418, 2 8 2017.
[17]