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
Scientists print sensors on gummi candy: creating microelectrode arrays on soft materials
21.06.2018 | Technische Universität München
Electron sandwich doubles thermoelectric performance
20.06.2018 | Hokkaido University
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
22.06.2018 | Materials Sciences
22.06.2018 | Earth Sciences
22.06.2018 | Life Sciences