Wind turbines operate under great turbulence with consequences for grid stability

first_img PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen Play A movie of the trajectory of power output vs. wind speed signals for a wind turbine reveals very turbulent fluctuations. Credit: Patrick Milan, et al. ©2013 American Physical Society “Looking at an operating wind turbine, one may get the impression that the turbine turns smoothly, but looking at the power output, which is the consequence of the forces and torques inside the machinery, we see that the fluctuations are very turbulent,” Peinke told Phys.org. “Changes of MW (more than one thousand horsepower) in seconds become obvious. Thus one may compare a wind turbine with an airplane in the landing phase during a very windy situation. From outside, the airplane may look it’s going quite smoothly, but inside there is another impression caused by turbulent dynamics. One should also note that a wind turbine has to operate permanently in this ‘turbulent landing’ condition.” Citation: Wind turbines operate under great turbulence, with consequences for grid stability (2013, April 19) retrieved 18 August 2019 from https://phys.org/news/2013-04-turbines-great-turbulence-consequences-grid.html Journal information: Physical Review Letters Copyright 2013 Phys.org All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of Phys.org. The model also reveals that moderately intermittent wind power is converted to highly intermittent power output. In other words, wind turbines do not only transfer wind intermittency to the grid, but they also amplify it. For instance, the researchers observed that changes in wind speed of about 11 m/s within 8 seconds may cause nearby wind turbines to change their power output by about 80%. The researchers attribute this amplification to the nonlinear conversion process and fast reaction time of the output to changes in wind speed.”The features of small-scale turbulence are mapped by the wind turbines directly into the electric grid,” Peinke said. “As turbulence and in particular the statistics of small-scale wind fluctuations are still considered to be an unresolved problem, this lack of knowledge may become important in the power grids, especially if such power grid are dominated by wind power. As these phenomena take place in the range of seconds, the dynamics of the power grid in these time scales have to be investigated in detail. One has clearly to state that the first step to solve a problem is to be aware of it and to understand it.”The data also shows that wind power intermittency does not only affect the output of individual turbines, as previous research has shown, but it also extends to entire wind farms, which has not been observed before. The researchers explain that wind farm intermittency is somewhat counterintuitive, since it might be expected that summing the output of wind turbines will average out their turbulent fluctuations. However, wind farm intermittency may be explained by long-range correlations observed in winds. While the wind farm the scientists observed covered an area of about 4 km2, wind correlations have previously been observed to extend to lengths of hundreds of kilometers. Based on these observations, the researchers expect that wind farm intermittency effects may persist up to these large scales.Overall, the physicists conclude that their results stress the importance of accounting for the intermittent and multifractal nature of wind power when designing components for wind power, including energy storage technologies. They note that the situation is similar to the findings from many years ago of the intermittent and multifractal nature of the stock market. In both areas, frequent occurrences of fluctuations must be understood and accounted for in order to maintain stability and avoid widespread disruption.In the future, the researchers plan to further investigate the consequence of wind turbulence on grid stability and develop methods to minimize the negative effects. New turbulence models may help lead to new concepts that reduce the power and load fluctuations on the grid.”For all of these topics, a deep and comprehensive understanding of the complexity of turbulence is indispensable,” Peinke said. Explore further Using fluctuating wind power (Phys.org) —While previous research has shown that wind turbulence causes the power output of wind turbines to be intermittent, a new study has found that wind turbulence may have an even greater impact on power output than previously thought. The researchers modeled the conversion of wind speed to power output using data from a rural wind farm. The results showed that the intermittent properties of wind persist on the scale of an entire wind farm, and that wind turbines do not only transfer wind intermittency to the grid, but also increase it. The findings highlight the importance of fully understanding the physics of wind turbulence in order to ensure future grid stability. The researchers, Patrick Milan, Matthias Wachter, and Joachim Peinke, at the ForWind—Center for Wind Energy Research at the University of Oldenburg in Germany, have published their study “Turbulent Character of Wind Energy” in a recent issue of Physical Review Letters.In their paper, the researchers address the challenges that large-scale wind energy production may bring to future power grids. They explain that today’s grids are powered mainly by a few large generators with controllable input (mostly gas, coal, hydraulic, and nuclear power plants). Power generation from these sources can be modified automatically in order to balance power generation and consumption, and thus ensure grid stability. But while today’s power sources are largely controllable, wind power is uncontrollable and highly intermittent. For time scales larger than several minutes, the conversion of wind speed into electrical power can be modeled by a standard average power curve. But at smaller time scales, the researchers found that the conversion process diverges from this curve. Instead, short-scale conversion follows a more complex pattern involving multifractal scaling that is reminiscent of a 1962 theory of turbulence developed by mathematician Andrey Kolmogorov. Screenshot of a movie (see below) showing the power output vs. wind speed signals for a wind turbine. Credit: Patrick Milan, et al. ©2013 American Physical Society More information: Patrick Milan, et al. “Turbulent Character of Wind Energy.” PRL 110, 138701 (2013). DOI: 10.1103/PhysRevLett.110.138701 This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Hope in colours and canvas

first_imgSome extra faith can never be a bad thing. The core theme of Ekta Jain’s paintings is  ‘Hope and never to despair’. The illuminated niches , rays of sun lighting up the dark crevices, beams of radiance dispelling the gloom are subtle statements occupying the focal point in her creations.Jain’s artwork is autobiographical and bears a close resemblance to her ‘never say die’ spirit and cheerful demeanor, finding vivid translation in her  formations and fabrications on the canvas. Her abstracts are reflective of hope and faith; of assurance and conviction of trust and optimism. Also Read – ‘Playing Jojo was emotionally exhausting’There is a symmetrical oneness in her apparently diversified expressions like her name ‘Ekta’ which implies unity, uniformity, solidarity and homogeneity. Her play with colours started at a tender age till it metamorphosed into emphatic narrations. Her journey to urban spaces is punctuated by her desire to discover layers upon layers of soul’s responses to civility or lack of it. The innate desire led her to formulate and execute her concept without any formal exercise in art.Her paintings are like palimpsest. Elusive at times and evasive but at the end of it the works come across as strokes of hope and happiness.last_img read more

Bengal in sight as part of our move to boost bilateral ties

first_imgKolkata: Vietnam is looking at Bengal as a major gateway in its stride for developing trade relations with the Eastern states of the country, Ambassador, Embassy of Vietnam in India, Ton Sinh Thanh said on Wednesday.”Vietnam has received investment of 320 billion US dollars from across the world for 25,000 projects. But investment from India has been only 1 billion US dollars for 130 projects. This is a small amount and we want things to move. We want to attract more tourists to Vietnam from India as well as Bengal,” Thanh said at an interactive session on “Bila-teral Trade between India and Vietnam: Prospects and Way Ahead” at MCCI. Also Read – Heavy rain hits traffic, flightsSadhan Pande , state minister for Consumer Affairs, Self Help Group and Self Employment, who was the special guest at the event, urged the Ambassador to consider making Bengal a hub for the country. “Bengal is at the crossroad of South East Asia and you can move to any Eastern state from here. So, you may consider making Bengal a hub as part of your efforts to develop relationship between the two countries,” Pande said.He added that Vietnam needs to play a more positive role in attracting tourists from the country. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killed”People from the country as well as Bengal travel a lot to Bangkok and Bali. Vietnam should also come in the picture of wooing tourists from here,” he added.According to the Ambassador, only 1,10,000 Indians visited Vietnam, while a little over 1 million Indians went to Thailand. Pointing out connectivity as a constraint, he said, “We are working on improving connectivity between the two countries. A direct flight from Delhi to Vietnam is going to commence in September 2018. Bengal is also very much on our radar. The Indian government is promoting a Look East policy and developing closer business ties with South East Asia and Bengal is the gateway to the Eastern states,” Thanh said.last_img read more

1 more arrested for smuggling arms from RFI to Maoists

first_imgKolkata: The Special Task Force (STF) of Kolkata Police today arrested a man from Bihar on the charge of being involved in an arms smuggling racket that was busted here last week, the police said. Rajesh Kumar (35) alias Munna, was arrested from his residence in in Bihar’s Nalanda district a senior officer of the Kolkata Police’s STF unit said. Six people, including two Rifle Factory Ishapore (RFI) officials, were arrested by the Kolkata Police last week from the city’s Babughat area for their alleged involvement in smuggling arms to Maoists. Also Read – Heavy rain hits traffic, flightsRajesh’s name cropped up while interrogating the six accused, the officer said, adding, “He has been given transit remand by Bihar Sharif Court. He will be brought to Kolkata tomorrow.” Preliminary investigation revealed that the arms were smuggled out of Ichapur Rifle Factory with the help of its two officers.The racket was probably active since 2008 and supplying the arms and ammunition to Maoists in Bihar. STF sleuths were also probing whether they had supplied arms to insurgent groups in Nepal also.Charges of criminal conspiracy and habitually dealing in stolen property, along with the Arms Act has been slapped against the arrested six accused.The Kolkata Police STF had in September last year arrested a junior works manager of RFI for allegedly smuggling parts of SLR and INSAS rifles out of the factory and selling them to illegal arms manufacturers.last_img read more

Govt to develop Gandhi Bhavan into major tourist destination

first_imgKolkata: Following the direction of Chief Minister Mamata Banerjee, the state Government is taking a major step in developing Gandhi Bhavan in Beliaghata as one of the favourite tourist destinations in Kolkata.It may be recalled that the state government has set up a 46-member committee with the Chief Minister as its chairperson to celebrate the 150th birth anniversary of Mahatma Gandhi. The first meeting of the committee was held on April 23 and decision to undertake necessary task for proper renovation of the heritage structure was also taken. The state Public Works Department (PWD) carries out the maintenance work of the structure at present. A programme is also scheduled to be held at Gandhi Bhavan in Beliaghata on October 2. It may be mentioned that the structure in Beliaghata is of immense importance as Gandhiji had spent around 25 days in that bhavan. Also Read – Heavy rain hits traffic, flightsSources said Vivek Kumar, Principal Secretary of the Information and Cultural Affairs department, visited the place last week and held a high-level meeting with concerned officials. A senior official from the state PWD was also present in the meeting, where detailed discussions on tasks that need to be carried out were held.An official said foreign tourists often visit the place. Hence, initiative has been taken to ensure that it gets a proper place on the state’s tourism map. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedA roadmap will be chalked out and based on the same, task will be carried out to develop the place as a destination for people visiting Bengal from different parts of the country and abroad.There is garden all around the house and it is properly maintained. Now, steps will be taken to develop the area around Gandhi Bhavan. Since a lot of foreign tourists often visit the place, steps will also be taken to ensure that they reach the place easily without facing any trouble, sources said. All the tasks will be taken up only after the roadmap is prepared. According to an officer, the work of preparing the same has already started. Help of the concerned PWD officials would also be taken, if needed, to prepare the roadmap. It may be mentioned that to celebrate the 150th birth anniversary of mahatma Gandhi, the state government will publish a booklet named as “Father of the Nation” containing speeches of Gandhiji.last_img read more

Nazi train with 200 million worth of treasure discovered

first_imgTwo treasure hunters claim to have found a mysterious Nazi train which disappeared on its way to Germany from Hungary in 1945 carrying guns, gems and other valuable items, including paintings estimated to be worth up to USD 200 million.A Pole and a German claim to have located the train and are seeking 10 per cent of the value of the findings.The 150-metre-long train disappeared in 1945, packed with guns, industrial equipment, gems and other valuable treasure. Also Read – Nine hurt in accident at fireworks show in French resortThe loot was from the then East Germany city of Breslau, now called Wroclaw and part of Poland, as the Red Army closed in at the end of World War II.It is believed that the train entered a tunnel near Ksiaz Castle in the mountainous Lower Silesian region and never emerged. The tunnel was later closed and its location long forgotten.Local authorities in Poland’s southwestern district of Walbrzych said they have been contacted by a law firm representing the two treasure hunters, ‘express.co.uk’ reported. Also Read – Pakistan Army ‘fully prepared’ to face any challenge: Army spokesman“Lawyers, the army, the police and the fire brigade are dealing with this. The area has never been excavated before and we don’t know what we might find,” Markia Tokarska, a Walbrzych council officer said.Trains were used to spirit Nazi loot back to Berlin as US-led Allied and Soviet forces surged towards the German capital from the west and the east in 1945.In the case of the so-called “Gold Train”, Nazi forces sent 24 freight carriages from Budapest towards Germany, filled with family treasures.  These included gold, silver and paintings seized from Hungarian Jews and estimated to be worth up to$200 mn.last_img read more

Two arrested in Bagdogra murder case

first_imgSiliguri: Two persons have been arrested in connection with the murder of a couple at Bagdogra near here, a senior police officer said. The two persons were identified as Sanjay Tamang and Bhumika Sheva and the latter was an employee of the victim, Ajay Kushwah, who used to supply staff for catering service. Both of them were arrested from the couple’s house at Sukantanagar locality yesterday, DCP Tarun Haldar said. Old enmity and greed for money had led to the killing of the couple — Ajay Kushwah and Meena Kushwah, DCP Tarun Haldar said. Also Read – Rain batters Kolkata, cripples normal life Ajay Kushwah had received payment from a customer on that day and Bhumika Sheva, who used to stay in the third floor of his house, had seen him keeping the money, the DCP said. She had told Sanjay Tamang, with whom she was in a relationship, about it and Tamang decamped with the money. Bhumika’s room was found locked from outside on that day while the rooms of other tenants were not locked from outside, the DCP said. During inquiry, the police came to know that Bhumika Sheva was present in the third floor of the house and she was awake when the incident had occurred. Money kept in the house was also found to have been stolen. This made the police suspicious and they started questioning her following which the duo were arrested. When the employees had come to the couple’s house after completing their work on Saturday, they had found the bodies lying in a pool of blood.last_img read more

Promoting JK Tourism

first_imgIn an initiative to strengthen tourism and to promote the culture of Jammu and Kashmir, Tourism Department organised a massive road show at Lalit Hotel in the national Capital. North India’s prominent travel trade representatives were invited to witness the impressive presentation from the department which showcased Jammu and Kashmir as one of the best destinations for its natural beauty, landscapes, gushing water streams, adventure tourism, crafts and cuisine, history and heritage, adventure tourism, lake tourism, MiCE and golf tourism. Also Read – ‘Playing Jojo was emotionally exhausting’Farooq Ahmed Shah, Secretary, Tourism  briefed the gathering about the 5500 year old history of Kashmir, the heritage and hospitality of the state for which Jammu and Kashmir is famous all over the world. He assured to provide best and upgraded services to visitors in 2016.RK Verma, Director, Tourism, Jammu; Mahmood A Shah, Director, Tourism, Kashmir and other officials of Tourism, JKTDC and SKICC were present at the road show.last_img read more

Govt taking all steps to aid growth of teleindustry CM

first_imgKolkata: Chief Minister Mamata Banerjee tweeted on World Television Day, mentioning the initiatives taken by her government for further growth of the tele-industry and benefit of television artistes and technicians.In a tweet on Wednesday, the Chief Minister stated: “Today is #WorldTelevisionDay. To give more support to the television industry, we are building the tele academy (complex) at Baruipur, #Bangla.” It may be recalled that on January 18, the Chief Minister had addressed the Tele Academy Awards 2017-18 that was held at Najrul Mancha. In the same programme, Banerjee had stressed upon the need of setting up the tele academy at Baruipur in South 24-Parganas. She had maintained that construction of the tele academy will be completed within a year. Also Read – Rain batters Kolkata, cripples normal lifeIt may be mentioned that setting up the tele academy will be of great help for the people involved in the industry. It will also inspire more people to get involved in the industry. The tele academy at Baruipur will be a state-of-the-art one, with all sorts of facilities available in it. Moreover, it will open a new arena for the tele-industry in the state. In the tweet, Banerjee has also maintained: “We have also raised the mediclaim for television artistes and technicians from Rs 1.5 lakh to Rs 2.5 lakh annually.” Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedIt may be recalled that the announcement regarding the increase in the amount of medical insurance was made by the Chief Minister in a January 18 programme. She had said while addressing the programme: “Television has become one of the most important medium now-adays. Many TV serials have become popular. A large number of people are involved in the profession. The artistes toil hard to do a serial. They often work till late night. We have decided to increase the medical insurance for the television artistes from Rs 1.5 lakh to 2.5 lakh per annum, in addition to the Rs 1 lakh accident benefit that they get.” Besides announcing the medical insurance, the Chief Minister also took a series of other initiatives to support the television artistes and technicians.last_img read more

State to raise issue with NIOS over DEIEd exams new dates

first_imgKolkata: State Education minister Partha Chatterjee on Monday expressed his displeasure over the National Institute of Open Schooling (NIOS)’s decision in cancelling the D.El. Ed examination in Bengal, citing leakage.”The test has been cancelled only in Bengal but not in any other state where the examination was held. When an examination is cancelled for alleged leakage, it should be done in all the states where the examinations are supposed to be held. Why only in Bengal? Is the NIOS regulated by the Centre,” Chatterjee questioned. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedThe rescheduling of the examination on February 3 in which candidates have to appear for two subjects each of three hours’ duration has also been an area of concern for those who have already sat for the examination held on December 20 and 21 respectively. The state Education secretary has already written a letter to the concerned authorities either to revoke its decision of cancellation or reconsider the rescheduled date. “The teachers have submitted a deputation to me citing their difficulty to appear for two papers on a single day. So we have decided to raise the issue with the NIOS,” Chatterjee said. Also Read – Bose & Gandhi: More similar than apart, says Sugata BoseThe teachers who have been already teaching in institutions but do not have B.Ed degree can clear D.El. Ed examination and accordingly meet the requisite criteria for teaching as mandated by the National Council of Teacher Education (NCTE). Meanwhile, the state Education department has decided to raise the salary of Siksha Bandhus from Rs 5,994 to Rs 8,392 a month. There are presently 3,925 Siksha Bandhus working at the grass-root level of Sarba Siksha Abhiyan (SSA). “The salary of those associated with project management related work under the SSA will also be enhanced by 40 percent on an average,” Chatterjee said. The minister expressed his optimism that induction of Class V in primary education will be completed by 2020 with some areas to be worked upon.last_img read more