We rely on different energy sources for producing electricity to our national grid. Some of these, such as wind and solar power, cannot generate a steady flow of electricity. In order to maintain a steady voltage in the power grid, it is the Francis turbine used in hydropower that compensates for the fluctuations that occur.
– The start-stop sequence creates huge forces on the turbine runner. We have to stop the turbine in a controlled manner to reduce wear and thereby increasing the life of the turbine, says Chirag Trivedi, researcher at Luleå University of Technology.
Chirag Trivedi conducts research on how Francis turbines are being affected by the start-stop sequence that occurs becauseof fluctuations in the national power grid. To highlight the problems caused by fluctuations in the power grid, Chirag mentions one of the world’s biggest-ever blackouts that recently occurred in his home country India
- In July 2012 the North and Northeast power grid of India collapsed due to a sudden fall of frequency and voltage. This resulted in an emergency shutdown of all connected power plants including hydroelectric turbines. More than 19 states and 600 million people were affected for hours. For instance, trains and metro were stopped, causing huge problems.
Develops an optimized scheme
Fluctuations may also come from varying demand for electricity and faults on power lines. Hydroelectric power plants (turbines) are used to balance the electricity flowing through the power grid according to variations in supply and demand. This is unfavourable since the turbine is not designed to generate variable electricity, leading to increased wear. By examining how a turbine is affected during the ten seconds of a start-stop sequence, Chirag will be able to develop a scheme that will optimize how the turbine stops and starts.
Collaboration between India, Sweden and Norway
Chirag Trivedi belongs to the Indian Institute of Technology, Roorkee (IIT Roorkee), one of India's top universities. His research is a collaboration between IIT Roorkee, Luleå University of Technology (LTU), and the Norwegian University of Science and Technology in Trondheim (NTNU). At NTNU Chirag will conduct experimental measurements on a Francis turbine and at LTU he will carry out Computational Fluid Dynamics (CFD) simulations on the complete turbine, which requires huge computational power. Chirag is grateful for the opportunity of coming to LTU for conducting his research:
– Everything is perfect here. I have access to cutting-edge equipment, it is a nice working environment and my colleagues are friendly and very much helpful. The library is great and I have access to all literature needed for my research. I think Luleå is a very beautiful place and I have really enjoyed the summer here, Chirag says.