Control valves in Hydro power plants

Who is in control?

Christian Borrmann - 2 April 2015

Control valves are crucial components that contribute to a sustainable concept of hydropower.

About the author

Mr Christian Borrmann
Christian Borrmann is the Editor-in-Chief of Valve World magazine and is the coordinator for the Valve World Conference in Europe.
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Control valves are a key element to the flow control industry. In a recent article that I read, I learnt about an ongoing project in Brazil. The project is scheduled to be completed in 2016 and needless to say, valves are going to be a vital part of it.

The project is located in Santo Antônio in Rondônia and it is a hydropower plant expansion. The project on the river Madeira will consist of 50 turbines delivering a maximum power of 3,568 megawatts by the end of the year 2016 – enough to supply electricity to 45 million people.

In the article, the valve manufacturer states that for the 50 turbines only two control valves per turbine will be needed for the hydraulic cylinders to move the runner blades and the distributor wicket gates in each Turbine.

The valves have a piston diameter size of 80mm and works as follows: the piston actuated by a servo valve glides within a spheroidal graphite iron housing up and down. If, for instance, the wicket gates or the runner blades should be closed, the correspondent piston moves downwards with accurate precision. As soon as the gates or blades are supposed to be open again, the piston moves up. The assigned pressure pushes the oil towards the hydraulic cylinder at the turbine. As a result, the actuators move the huge turbine blades and the wicket gates.

According to the author the system at Santo Antônio is a unique system and the valves used in the plant are designed to fit in. The manufacturer uses a simplified design in order to avoid potential errors in the system and explain that this design comes from collecting experiences for more than 150 years in this field of application.

A challenge that many suppliers have when it comes to supplying to Brazil is that the government regulation says that industrial goods have to be local. Hence a lot of companies open offices and plants in the country in order to keep their place on the Brazilian market or get into it. However, whereas most of the hydroelectric components for the plant are assembled at the plant, the control valves for this project are manufactured in Germany and then shipped to Brazil and then onsite, the manufacturer supplies the service and installation of the valves which will then support the power units and keep at Santo Antônio online for future decades.

Header image copyright: Voith Hydro

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