To provide a solution to the problems caused to wind turbines by sudden dips in voltage in a part of the electric grid. This was the objective of industrial engineer and member of INGEPER Research Team at the Public University of Navarre, Jesús López Taberna.
The fruit of his research is a rotor model which enables anticipating how the wind power unit will behave in these situations. Mr López has patented two techniques of protection, one of which has already been transferred to a manufacturer who will exploit it at international level. This system allows the generator turbine to remain in operation during these voltage dips and thus prevent the wind energy converter from ceasing to function.
The title of the PhD is: “The behaviour of wind-powered generators with double-fed asynchronous motor during voltage dips”.
Over the past few years, the growth and development of wind energy converters has been slowed by problems that have arisen from the increase in the number of these connected to the electric grid. One of the most important problems is precisely the manner in which the wind generators behave during these voltage dips.
A voltage dip is a sudden reduction in potential in the electric grid, followed by a rapid return to its normal value. This, at times, can be caused by lightening or a tree falling on power cables but also due to a large company consuming a lot of energy in one go. This drop in voltage happens in a matter of milliseconds; “we are aware of it because the lights begin to flicker or because they go off and on momentarily – but, for a machine, this can be an eternity”, explained Mr López. In fact, an interruption of half a second in a productive process can cause the whole process to block and it may have to be reinitiated.
With wind generators, in the case of a voltage dip, the electronic part of the unit can burn out or otherwise be destroyed, unless a protection system is installed “The current system of protection, known as Crowbar, has the advantage of being able to protect the machine but the disadvantage of the machine coming to a halt”, pointed out Mr López. “For example, if a large company suddenly consumes a lot of current, the voltage drops. This causes the wind power units at El Perdon (Navarre) to disconnect and cease producing electricity. As a result, the power dip is even more accentuated and, consequently, it is even more difficult to bring the voltage up to its normal operating value”.
Taking into account that, in Spain, there are days that wind-powered energy can account for one third of electricity production, the problem can prove to be a serious one. The idea being worked on currently is focused on the generator behaving more as a conventional power station and not disconnecting during a voltage dip/power failure but helping to bring the grid voltage back up. This is why wind generator manufacturers are currently working on finding a new system of protection that is efficient and efficacious.
Two new protection techniques patented
“Before looking for a solution, the problem has to be studied from a theoretical perspective, i.e. why does this machine behave as it does when there is a voltage dip? And why, if we do not install a protection system, the machine starts to burn out”? The research produced a rotor model which was “sufficiently simple to be able to deal with without having to carry out simulations. A model in which we can see what role each parameter of the machine plays, how they interact, how the current drops if we increase the leak inductances, etc”.
Once this model was developed, it was more or less easy to propose solutions. “The most important thing is that we have achieved solutions that enhance the behaviour of the machine without any need to change anything, except the control. It’s like changing the version of a text treatment programme on the computer, without needing to change the PC. There a number of computers inside a wind energy converter and one of these – that which controls the electrical machinery – is the one the control of which we have proposed to modify in order to enhance the behaviour of the machine”.
Jesús López Taberna specifically proposed in his PhD thesis two systems of protection and both have been patented. The first, only requiring changing the control of the machine converter, has been transferred to a manufacturer for introduction into wind parks worldwide; the other requires changing elements inside the machine and continues to be developed for applications in new creation wind generators.
Irati Kortabitarte | alfa
Researchers use light to remotely control curvature of plastics
23.03.2017 | North Carolina State University
TU Graz researchers show that enzyme function inhibits battery ageing
21.03.2017 | Technische Universität Graz
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
23.03.2017 | Life Sciences
23.03.2017 | Power and Electrical Engineering
23.03.2017 | Earth Sciences