Contact

After defending my thesis here in Norway, I will come back to Spain to study a masters in Renewable Energies in Madrid, you can contact me to my email:

pedrocamun@hotmail.com

 

Conclusions

An initial theoretical approach of the topologies of the plants studied in this thesis has been necessary to been able to develop the model and understand the response of them to different situations, a modelling process of electrical devices also requires advanced knowledge on electrical engineering and control engineering in the case of the controller.

Equivalent circuits have proven to be a successful tool for modelling techniques by simplifying the electrical processes taking part in the devices presented in this thesis, the development of the models has been done quickly thanks to this tool and oers a useful way to explain how the devices work to general public.

Matlab© Simulink works perfectly for modelling since it is an advanced software with a wide range of tools that allows the user to get into high level of details of the models designed in this thesis and in future works. The availability of import data and manipulate it with exibility increases the
applications of the software in hardware-in-the-loop simulations like the ones performed in the Smart Energies laboratory.

The availability of a laboratory in the Fredrikstad campus for hardware-int-the-loop simulations has enriched this thesis and allowed the verication of the reliability of the models developed, despite of the devices especially in the wind turbine setup were exactly the same than the developed on the
model, the PV setup has validate the PV models as a very precise approach to the real devices, since the curves drawn when adapted the model to the devices on the laboratory had a close relationship with the measurements taken in the experiment.

Models have been proven to be an approach with high level of detail to the behaviours of the systems studied in this thesis, oering a proper response in terms of generated power very useful for the industry. Still, the competences required for a bachelor thesis have limited the level of detail of this thesis, not making able to develop models that considering more physical processes like aging in the chase of batteries, partial shading in the case of PV panels and pitch control or different wind speeds in each blade in the case of the wind turbine.

 

Simulations

One wind scenario and other sunlight scenario has been applied to the simulation models.

Low wind speed scenario

For this scenario, a wind that gets oscillating softly around the value of 10m/s has been implemented.

 

The plant injects a steady active power of around 1MW when wind stabilizes, the wind turbine works better when approaching the nominal wind speed of 12m/s producing less oscillations in the wave of the output active power.

Sunny day scenario

For this scenario, the typical curve of daily irradiance has been implemented.

 

 

Experiments

With the help of the laboratory of Smart Energies , I performed some experiments, here I present the two main ones.

Wind profile

For this experiment, a wind prole has been implemented in the wind turbine setup, with the help of the DFIG Control virtual tool, dierent measurements has been made and are displayed .Pitch angle control on the setup is increasing the angle of attack of the blades in order to reduce
mechanical stress on the turbine and allow the system to work over the nominal speed.

Hybrid solution with BESS

For this experiment, the battery that is part of the setup has been used in order to display the behaviour of a hybrid solution of PV and BESS for a power plant and the grid. A solar prole will be created on the Solar Panel software and the battery will be controlled via SCADA Viewer to make it charge and discharge when the PV system is injecting different powers.

 

A complete day has been scaled in 12 minutes (720 seconds), so one hour corresponds to 30 seconds in the simulation. The solar prole generated in the Solar Panel software is an average generation curve with a partial shading around 13:00. The battery have been controlled from the grid in order inject power on the grid, use part of the PV power and supply power in case of no sunlight.

 

During the rst hours of the day, the battery is injecting power on the grid, discharging at nominal power (1500 W), when the sun starts to rise, the battery starts decreasing the power until the power injected to the grid is around zero (since these hours are considered when the price of electricity is minimum), when sunlight starts to become more intense, the battery starts to charge, taking the PV power and maintaining zero total power.

 

Wind and solar plants

Wind energy power plants

A wind turbine power plant is a system that converts the kinetic energy of the wind into electrical energy by using rotating mechanism attached to a generator, they can vary the scale from small microturbines capable to support the demand of a small installation to big turbines of 10MW that put together can conform big power plants that play an important role in the grid.

Fixed speeds turbines have the advantage that they can use synchronous motors and they can be connected directly to the grid since they produce a  fixed frequency, adjustable speed generators need the implementation of a frequency converter before connecting them to the grid but they can work with variable wind speed without producing stresses in the mechanical parts of the turbine. Since the wind speed is variable and highly unpredictable, it is more desired the implementation of an adjustable speed generator that can work with different wind speeds.

There are two types of wind turbines, depending on the orientation of the rotatory axes they can be horizontal and vertical, in my thesis I´m working with the horizontal since they provide more energy.

 

PV Plants

Photovoltaic (PV) power plants use semiconductor to convert the energy from the solar irradiation directly into electricity, actually is one of the most used renewable energy sources since they are portableand easy to install.
One of the main disadvantages of a PV power plant is that the generation can’t be controlled, it depends entirely on the atmospheric conditions of each day, the implementation with technologies of energy storage makes them more exible and avoid the energy surplus.

Unlike wind power plants, part of the atmospheric conditions like irradiance and daylight hours are constant and fully predictable, PV plants have to be prepared only to situations of partial shading. The PV panels are the most important component of a PV plant, those devices are responsible of the
energy generation, PV panels use semiconducting materials like silicon to generate electricity from the sunlight, the amount of electricity generated is directly proportional to the irradiance at the moment, making he energy generated variable through the day.

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About this thesis

Hi! I am Pedro Luis Camuñas García-Miguel, and I am an electrical engineering undergraduate. I am finishing my degree in Østfold University College as an exchange student, here I am doing my bachelor thesis. I come from Spain, where renewable energies have a bright future, and my goal is to increase and deepen my knowledge in this interesting technology and in its implementation in the Smart Grids scenario.

In this page I will present the development and results of my thesis, with the help of Matlab®  I am going to model the physical behavior of the elements of a distribution grid with storage systems, this will be:

  • A 2 megawatts wind turbine
  • A PV plant
  • A battery system

I will build a high detailed model with all the power electronics converters involved in the subsystems and all the processes that occurs in them, then I will perform diverse scenarios where I will monitor the response of my model. Then, with the help of the Smart Energies laboratory present at the campus in Fredrikstad I will compare the different models with scenarios in the setups available there.

A manufacturer company or a researcher will be able to use this models as tools by implementing technical specifications of the devices involved in the systems and study the response of then at different preset situations, this models also can be integrated in a SCADA system for further research in Smart Grids technologies.

But first, I’m going to explain to you some of the key concepts of this thesis:

 

What’s the deal with renewable energies?

The main deal with renewable energies it´s that they are not able to be controlled, a carbon plant or a nuclear power plant can be (more or less) put on service when required while wind and sunlight can´t be controlled by humans. This means that is humans, and not the nature, who has to be able to adapt to different situations, changing radically the paradigm in the design of the plants.

Especially atention has to be put on power converters, since the quality of the power and the efficiency of the plant in every operation point on the plant is their responsability. Also, energy storage systems are necessary in order to provide a power backup in case sun and wind are not in the mood of providing enough power on a grid.

 

Why Matlab?

Matlab is one of the most tools an engineer can ever have, this program allows to perform a wide range of calculations in a relatively easy way, the Simulink platform present in this software makes possible to emulate even the smallest detail of a system, and study its response.

 

What is SCADA? What are Smart Grids?

SCADA means Supervisory Control and Data Acquisition, this softwares are being implemented in the grid in order to improve communications between generators, consumers and transmision lines, making the electrical grid more secure, efficient and controllable.

A grid that has a high impact in communications technologies, and that can be controlled with relatively ease is called a Smart Grid, in Europe and along the world this new concept of electrical grid is being more and more spread.